Documents published in 2009 : Scipedia

The use of taborr as a heavy oil upgrader
N. Brecher, N. Mones

Collection of open reports in transport research (2009). 4

Abstract
Preliminary testing has shown that Western Research Institute's (WRI) Tank Bottom Recovery and Remediation (TaBoRR{reg_sign}) technology shows promise for heavy oil upgrading. Approximately 70 to 75 wt% of a Canadian Cold Lake bitumen feed was converted to a partially upgraded overhead product that could be transported directly by pipeline or blended with the parent bitumen to produce transportable crude. TaBoRR{reg_sign} was originally developed to remediate tank bottom wastes by producing a distillate product and solid waste. TaBoRR{reg_sign}'s processing steps include breaking a water-oil emulsion, recovering a light hydrocarbon fraction by distillation in a stripper unit, and pyrolyzing the residua reducing it to additional overhead and a benign coke for disposal. Cold Lake bitumen was tested in WRI's bench-scale equipment to evaluate the potential use of TaBoRR{reg_sign} technology for heavy oil upgrading to produce a stable, partially (or fully) upgraded product that will allow diluent-reduced or diluent-free transportation of bitumen or ultra-heavy crudes to market. Runs were conducted at temperatures of low, intermediate and high severity in the stripper to produce stripper overhead and bottoms. The bottoms from each of these runs were processed further in a 6-inch screw pyrolyzer to produce pyrolyzer overhead for blending with the corresponding stripper overheads.moreÂ Â» Proceeding in this fashion yielded three partially upgraded crudes. The products from TaBoRR{reg_sign} processing, the parent bitumen, and bitumen blends were subjected to stability and compatibility testing at the National Centre for Upgrading Technology (NCUT). Chemical analyses of the overhead product blends have met pipeline specifications for viscosity and density; however the bromine number does not, which might indicate the need for mild hydrotreating. Storage stability tests showed the blends to be stable. The blends were also soluble and compatible with most other Alberta crudes.Â«Â le Document type: Report
Abstract
Preliminary testing has shown that Western Research Institute's (WRI) Tank Bottom Recovery and Remediation (TaBoRR{reg_sign}) technology shows promise for heavy oil upgrading. [...]
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A qualitative investigation of deposition velocities of a non newtonian slurry in complex pipeline geometries
S. Yokuda, A. Poloski, H. Adkins, A. Casella, R. Hohimer, N. Karri, M. Luna, M. Minette, J. Tingey

Collection of open reports in transport research (2009). 3

Abstract
The External Flowsheet Review Team (EFRT) has identified the issues relating to the Waste Treatment and Immobilization Plant (WTP) pipe plugging. Per the reviewÂs executive summary, ÂPiping that transports slurries will plug unless it is properly designed to minimize this risk. This design approach has not been followed consistently, which will lead to frequent shutdowns due to line plugging.Â To evaluate the potential for plugging, testing was performed to determine critical velocities for the complex WTP piping layout. Critical velocity is defined as the point at which a moving bed of particles begins to form on the pipe bottom during slurry-transport operations. Pressure drops across the fittings of the test pipeline were measured with differential pressure transducers, from which the critical velocities were determined. A WTP prototype flush system was installed and tested upon the completion of the pressure-drop measurements. We also provide the data for the overflow relief system represented by a WTP complex piping geometry with a non-Newtonian slurry. A waste simulant composed of alumina (nominally 50 ?m in diameter) suspended in a kaolin clay slurry was used for this testing. The target composition of the simulant was 10 vol% alumina in a suspending medium with a yieldmoreÂ Â» stress of 3 Pa. No publications or reports are available to confirm the critical velocities for the complex geometry evaluated in this testing; therefore, for this assessment, the results were compared to those reported by Poloski et al. (2008) for which testing was performed for a straight horizontal pipe. The results of the flush test are compared to the WTP design guide 24590-WTP-GPG-M-0058, Rev. 0 (Hall 2006) in an effort to confirm flushing-velocity requirements.Â«Â le Document type: Report
Abstract
The External Flowsheet Review Team (EFRT) has identified the issues relating to the Waste Treatment and Immobilization Plant (WTP) pipe plugging. Per the reviewÂs executive [...]
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Distributed data flow for in situ visualization and analysis at petascale
D. Laney, H. Childs

Collection of open reports in transport research (2009). 2

Abstract
We conducted a feasibility study to research modifications to data-flow architectures to enable data-flow to be distributed across multiple machines automatically. Distributed data-flow is a crucial technology to ensure that tools like the VisIt visualization application can provide in-situ data analysis and post-processing for simulations on peta-scale machines. We modified a version of VisIt to study load-balancing trade-offs between light-weight kernel compute environments and dedicated post-processing cluster nodes. Our research focused on memory overheads for contouring operations, which involves variable amounts of generated geometry on each node and computation of normal vectors for all generated vertices. Each compute node independently decided whether to send data to dedicated post-processing nodes at each stage of pipeline execution, depending on available memory. We instrumented the code to allow user settable available memory amounts to test extremely low-overhead compute environments. We performed initial testing of this prototype distributed streaming framework, but did not have time to perform scaling studies at and beyond 1000 compute-nodes. Document type: Report
Abstract
We conducted a feasibility study to research modifications to data-flow architectures to enable data-flow to be distributed across multiple machines automatically. Distributed [...]
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The physics of galaxy evolution with EAGLE.
M. Puech, M. Lehnert, Y. Yang, J. Cuby, S. Morris, C. Evans, B. Neichel, T. Fusco, G. Rousset, H. Flores

Collection of open chapters of books in transport research (2009). Vol. 2009, 42

Abstract
One of the prominent science goal of the ELTs will be to study the physics and mass assembly of galaxies at very high redshifts. Here, we present the galaxy evolution science case for EAGLE, which is a NIR multi-integral field spectrograph for the E-ELT currently under phase A study. We summarize results of simulations conducted to derive high-level requirements. In particular, we show how we have derived the specifications for the ensquared energy that the AO system needs to provide to reach the scientific goals of the instrument. Finally, we present future strategies to conduct galaxy surveys with EAGLE. Document type: Part of book or chapter of book
Abstract
One of the prominent science goal of the ELTs will be to study the physics and mass assembly of galaxies at very high redshifts. Here, we present the galaxy evolution science [...]
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Cordon pricing consistent with the physics of overcrowding
N. Geroliminis, D. Levinson

Collection of open chapters of books in transport research (2009). Vol. 2009, 39

Abstract
This paper describes the modeling of recurring congestion in a network. It is shown that the standard economic models of marginal cost cannot describe precisely traffic congestion in networks during time-dependent conditions. Following a macroscopic traffic approach, we describe the equilibrium solution for a congested network in the no-toll case. A dynamic model of cordon-based congestion pricing (such as for the morning commute) for networks is developed consistent with the physics of traffic.Ê The paper combines VickreyÕs theory with a macroscopic traffic model, which is readily observable with existing monitoring technologies. The paper also examines some policy implications of the cordon-based pricing to treat equity and reliability issues, i.e. in what mobility level a city should choose to operate. An application of the model in a downtown area shows that these schemes can improve mobility and relieve congestion in cities. Document type: Part of book or chapter of book
Abstract
This paper describes the modeling of recurring congestion in a network. It is shown that the standard economic models of marginal cost cannot describe precisely traffic congestion [...]
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Enhancing application identification by means of sequential testing
M. Jaber, C. Barakat

Collection of open chapters of books in transport research (2009). Vol. 2009, 37

Abstract
One of the most important challenges for network administrators is the identification of applications behind the Internet traffic. This identification serves for many purposes as in network security, traffic engineering and monitoring. The classical methods based on standard port numbers or deep packet inspection are unfortunately becoming less and less efficient because of encryption and the utilization of non standard ports. In this paper we come up with an online iterative probabilistic method that identifies applications quickly and accurately by only using the size of packets. Our method associates a configurable confidence level to the port number carried in the transport header and is able to consider a variable number of packets at the beginning of a flow. By verification on real traces we observe that even in the case of no confidence in the port number, a very high accuracy can be obtained for well known applications after few packets were examined. Document type: Part of book or chapter of book
Abstract
One of the most important challenges for network administrators is the identification of applications behind the Internet traffic. This identification serves for many purposes [...]
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Looking for the 3d picture the spatio temporal realm of student controllers
M. Tavanti, M. Cooper

Collection of open chapters of books in transport research (2009). Vol. 2009, 35

Abstract
Employing three-dimensional displays in Air Traffic Control (ATC) has been the object of study and debates for numerous years. Although empirical studies have often led to mixed results, some preliminary evidence suggests that training could be a suitable domain of application for 3D interfaces. Little evidence, however, is available to fully support this claim. We attempted to fill this gap with a project that aims at studying and evaluating 3D displays for ATC training purposes. This paper describes the first steps of this project, by reporting and discussing the results of a study aiming at understanding whether ATC trainees form a three-dimensional image of air traffic and at comprehending what the nature of this `3D picture' is. Document type: Part of book or chapter of book
Abstract
Employing three-dimensional displays in Air Traffic Control (ATC) has been the object of study and debates for numerous years. Although empirical studies have often led to [...]
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Detection of linear structures in remote sensed images
R. Gao, W. Bischof

Collection of open chapters of books in transport research (2009). Vol. 2009, 34

Abstract
Over the past decades, considerable progress had been made in developing automatic image interpretation tools for remote sensing. There is, however, still a gap between the requirements of applications and system capabilities. Interpretation of noisy aerial images, especially in low resolution, is still difficult. We present a system aimed at detecting faint linear structures, such as pipelines and access roads, in aerial images. We introduce an orientation-weighted Hough transform for the detection of line segments and a Markov Random Field model for combining line segments into linear structures. Empirical results show that the proposed method yields good detection performance. Document type: Part of book or chapter of book
Abstract
Over the past decades, considerable progress had been made in developing automatic image interpretation tools for remote sensing. There is, however, still a gap between the [...]
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Minimum delay load balancing through non parametric regression
F. Larroca, J. Rougier

Collection of open chapters of books in transport research (2009). Vol. 2009, 33

Abstract
Network convergence and new applications running on end-hosts result in increasingly variable and unpredictable traffic patterns. By providing origin-destination pairs with several possible paths, load-balancing has proved itself an excellent tool to face this uncertainty. Formally, load-balancing is defined in terms of a convex link cost function of its load, where the objective is to minimize the total cost. Typically, the link queueing delay is used as this cost since it measures its congestion. Over-simplistic models are used to calculate it, which have been observed to result in suboptimal resource usage and total delay. In this paper we investigate the possibility of learning the delay function from measurements, thus converging to the actual minimum. A novel regression method is used to make the estimation, restricting the assumptions to the minimum (e.g. delay should increase with load). The framework is relatively simple to implement, and we discuss some possible variants. Document type: Part of book or chapter of book
Abstract
Network convergence and new applications running on end-hosts result in increasingly variable and unpredictable traffic patterns. By providing origin-destination pairs with [...]
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Evolutionary and preferential attachment models of demand growth
T. Friesz, C. Kwon, D. Bernstein

Collection of open chapters of books in transport research (2009). Vol. 2009, 32

Abstract
It is widely acknowledged that, to create models for transportation planning that recognize the essential dynamic character of passenger network flows, one must consider two time scales: the so-called within-day time scale and the day-to-day time scale. Substantial progress has been made in modelling within-day dynamic flows for fixed trip matrices; one of the most widely acknowledged models for this purpose is the dynamic user equilibrium model proposed by Friesz et al. (1993) and studied by Xu et al. (1999), Wu et al. (1998), Friesz et al. (2001), Bliemer and Bovy (2003), and Friesz and Mookherjee (2006). In this chapter we propose two day-to-day models of demand growth compatible with a differential variational inequality formulation of the Friesz et al. (1993) model. The first of these employs dynamics inspired by evolutionary game theory, while the second uses the perspective of preferential attachment familiar from the network science and social network literature to create a model of demand growth. Additionally, numerical experiments to compare and contrast the two proposed theories of demand growth are described, along with hypotheses that one might address via such experiments. Document type: Part of book or chapter of book
Abstract
It is widely acknowledged that, to create models for transportation planning that recognize the essential dynamic character of passenger network flows, one must consider two [...]
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Computational fluid dynamics methods for gas pipeline system control
V. Seleznev

Collection of open chapters of books in transport research (2010). Vol. 2010, 49

Abstract
At the present level of development of long, branched gas transmission networks (GTN), solving the problems of improving safety, efficiency and environmental soundness of operation of industrial pipeline systems calls for the application of methods of numerical simulation. The development of automated devices for technical inspection and process control, and availability of high-performance computer hardware have created a solid technical basis to introduce numerical simulation methods into the industrial practice of GTN analysis and operation. One of the promising approaches for numerical analysis of GTN operating is the development and application of high-accuracy computational fluid dynamics (CFD) simulators of modes of gas mixture transmission through long, branched pipeline systems (CFD-simulator) (Seleznev, 2007). Actually, a CFD-simulator is a special-purpose software simulating, in online and real time modes with a high similarity and in sufficient detail, the physical processes of gas mixture transmission through a particular GTN. The development of a CFD-simulator focuses much attention to correctness of simulation of gas flows in the pipelines and to the impact produced by operation of relevant GTN gas pumping equipment (including gas compressor unit (GCU), valves, gas pressure reducers, etc.) and the environment upon the physical processes under study. From the standpoint of mathematical physics, a CFD-simulator performs numerical simulation of steady and transient, non-isothermal processes of a gas mixture flow in long, branched, multi-line, multi-section gas pipeline network. Such simulation is aimed at obtaining high-accuracy estimates of the actual distribution (over time and space) of fluid dynamics parameters for the full range of modes of gas mixture transmission through the specific GTN in normal and emergency conditions of its operation, as well as of the actual (temporal) distribution of main parameters of GTN equipment operation, which can be Document type: Part of book or chapter of book
Abstract
At the present level of development of long, branched gas transmission networks (GTN), solving the problems of improving safety, efficiency and environmental soundness of [...]
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The Taxation Of Motor Fuel : International Comparison
L. Eduardo, B. Jessica

Collection of open chapters of books in transport research (2009). Vol. 2009, 31

Abstract
This paper assesses whether the level of taxation of motor fuel is broadly appropriate in a group of countries (OECD, BRICs and South Africa) accounting for more than 80 percent of world greenhouse gas emissions. The analysis deals with emissions from oil combustion in transport, which account for about 40 percent of carbon dioxide emissions. In the benchmark specification, six countries (responsible, in turn, for more than 40 percent of worldwide motor-fuel greenhouse gas world emissions) would be undertaxing motor fuel. The authors evaluate the sensitivity of the results to the values of the elasticities and externalities that used in the analysis. They find that varying the values of these parameters (within the level of uncertainty reasonably associated with them) significantly affects the results. This implies that, while informative, the results must be taken as indicative. Further analysis for a particular country must rely on a well-informed choice for the values of the country-specific parameters. Document type: Book
Abstract
This paper assesses whether the level of taxation of motor fuel is broadly appropriate in a group of countries (OECD, BRICs and South Africa) accounting for more than 80 percent [...]
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Impacts Of Policy Instruments To Reduce Congestion And Emissions From Urban Transportation : The Case Of Sao Paulo, Brazil
A. Anas, G. Timilsina

Collection of open chapters of books in transport research (2009). Vol. 2009, 30

Abstract
This study examines impacts on net social benefits or economic welfare of alternative policy instruments for reducing traffic congestion and atmospheric emissions in São Paulo, Brazil. The study shows that expanding road networks, subsidizing public transit, and improving automobile fuel economy may not be as effective as suggested by economic theories because these policies could cause significant rebound effects. Although pricing instruments such as congestion tolls and fuel taxes would certainly reduce congestion and emissions, the optimal level of these instruments would steeply increase the monetary cost of travel per trip and are therefore politically difficult to implement. However, a noticeable finding is that even smaller tolls, which are more likely to be politically acceptable, have substantial benefits in terms of reducing congestion and emissions. Among the various policy instruments examined in the study, the most socially preferable policy option for São Paulo would be to introduce a mix of congestion toll and fuel taxes on automobiles and use the revenues to improve public transit systems. Document type: Book
Abstract
This study examines impacts on net social benefits or economic welfare of alternative policy instruments for reducing traffic congestion and atmospheric emissions in São [...]
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The impact of automation assisted aircraft separation on situation awareness
A. Dao, S. Brandt, V. Battiste, K. Vu, T. Strybel, W. Johnson

Collection of open chapters of books in transport research (2009). Vol. 2009, 28

Abstract
This study compared situation awareness across three flight deck decision aiding modes. Pilots resolved air traffic conflicts using a click and drag software tool. In the automated aiding condition, pilots executed all resolutions generated by the automation. In the interactive condition, automation suggested a maneuver, but pilots had the choice of accepting or modifying the provided resolution. In the manual condition pilots generated resolutions independently. A technique that combines both Situation Global Assessment Technique and Situation Present Awareness Method was used to assess situation awareness. Results showed that situation awareness was better in the Manual and Interactive conditions when compared to the Automated condition. The finding suggests that pilots are able to maintain greater situation awareness when they are actively engaged in the conflict resolution process. Document type: Part of book or chapter of book
Abstract
This study compared situation awareness across three flight deck decision aiding modes. Pilots resolved air traffic conflicts using a click and drag software tool. In the [...]
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Lessons from an overview of national transport surveys, from working group 3 of COST 355: Changing behavior toward a more sustainable transport system
J. Armoogum, K. Axhausen, J. Madre

Collection of open chapters of books in transport research (2009). Vol. 2009, 27

Abstract
Abstract\r This chapter summarizes some of the results from the Working Group National Travel Surveys in COST Action 355. All 50 presentations could not be reviewed here; thus, we focus on three crucial topics: \r \r the periodicity of data collection, but also its longitudinal aspects (advantages of continuous surveying, repeated cross-sections vs. panel surveys, etc.),\r \r \r new technologies for improving the efficiency and accuracy of mobility surveys (computer-assisted telephone, Web-based, interviews, GPS, GSM, RDS, etc.),\r \r \r innovative approaches, exemplified by qualitative surveys combined with conventional quantitative ones, and by biographical approaches. Document type: Part of book or chapter of book
Abstract
Abstract\r This chapter summarizes some of the results from the Working Group National Travel Surveys in COST Action 355. All 50 presentations could not be reviewed here; [...]
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Hierarchical modelling and model adaptivity for gas flow on networks
P. Bales, O. Kolb, J. Lang

Collection of open chapters of books in transport research (2009). Vol. 2009, 26

Abstract
We are interested in the simulation and optimization of gas transport in networks. Different regions of the network may be modelled by different equations. There are three models based on the Euler equations that describe the gas flow in pipelines qualitatively different: a nonlinear model, a semilinear model and a stationary also called algebraic model. For the whole network, adequate initial and boundary values as well as coupling conditions at the junctions are needed. Using adjoint techniques, one can specify model error estimators for the simplified models. A strategy to adaptively apply the different models in different regions of the network while maintaining the accuracy of the solution is presented. Document type: Part of book or chapter of book
Abstract
We are interested in the simulation and optimization of gas transport in networks. Different regions of the network may be modelled by different equations. There are three [...]
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Natural gas and geopolitics natural gas pipelines in the southern cone
D. Mares

Collection of open chapters of books in transport research (2009). Vol. 2009, 25

Abstract
Document type: Part of book or chapter of book
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An analysis of various policy instruments to reduce congestion, fuel consumption and CO2 emissions in Beijing
A. Anas, G. Timilsina, S. Zheng

Collection of open chapters of books in transport research (2009). Vol. 2009, 23

Abstract
Using a nested multinomial logit model of car ownership and personal travel in Beijing circa 2005, this paper compares the effectiveness of different policy instruments to reduce traffic congestion and CO2 emissions. The study shows that a congestion toll is more efficient than a fuel tax in reducing traffic congestion, whereas a fuel tax is more effective as a policy instrument for reducing gasoline consumption and emissions. An improvement in car efficiency would also reduce congestion, fuel consumption, and CO2 emissions significantly; however, this policy benefits only richer households that own a car. Low-income households do better under the fuel tax policy than under the efficiency improvement and congestion toll policies. The congestion toll and fuel tax require the travel cost per mile to more than triple. The responsiveness of aggregate fuel and CO2 are, approximately, a 1 percent drop for each 10 percent rise in the money cost of a car trip. Document type: Book
Abstract
Using a nested multinomial logit model of car ownership and personal travel in Beijing circa 2005, this paper compares the effectiveness of different policy instruments to [...]
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Developing a framework of common information space cis grounded theory analysis of airport cis
N. Selvaraj, B. Fields

Collection of open chapters of books in transport research (2010). Vol. 2010, 42

Abstract
The notion of Common Information Space (CIS) has been proposed in the field of Computer Supported Cooperative Work (CSCW) as a conceptual framework for analyzing cooperative work processes. The area is still in its formative years and requires more research to contribute to its development. This paper presents findings from an investigation undertaken for such an endeavor. Three perceptions of CIS are presented, which are, CIS as a sociotechnical arrangement, dynamic arrangement, and dependency management arrangement. These have been derived from review of existing research contributing to CIS notion development and Grounded Theory analysis of collaborative work process in air traffic control setting. The findings presented in this paper provide a comprehensive and consolidated view of the notion development. The paper contributes to the ongoing discussion of CIS notion development by making theoretical as well as methodological contribution. Document type: Part of book or chapter of book
Abstract
The notion of Common Information Space (CIS) has been proposed in the field of Computer Supported Cooperative Work (CSCW) as a conceptual framework for analyzing cooperative [...]
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Static timing analysis for hard real-time systems
R. Wilhelm, S. Altmeyer, C. Burguière, D. Grund, J. Herter, J. Reineke, B. Wachter, S. Wilhelm

Collection of open chapters of books in transport research (2010). Vol. 2010, 41

Abstract
Hard real-time systems have to satisfy strict timing constraints. To prove that these constraints are met, timing analyses aim to derive safe upper bounds on tasks execution times. Processor components such as caches, out-of-order pipelines, and speculation cause a large variation of the execution time of instructions, which may induce a large variability of a tasks execution time. The architectural platform also determines the precision and the complexity of timing analysis.\r \r This paper provides an overview of our timing-analysis technique and in particular the methodological aspects of interest to the verification community. Document type: Part of book or chapter of book
Abstract
Hard real-time systems have to satisfy strict timing constraints. To prove that these constraints are met, timing analyses aim to derive safe upper bounds on tasks execution [...]
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The Elite Brain Drain
R. Hunter, A. Oswald, B. Charlton

Collection of open chapters of books in transport research (2009). Vol. 2009, 22

Abstract
We collect data on the movement and productivity of elite scientists. Their mobility is remarkable: nearly half of the world's most-cited physicists work outside their country of birth. We show they migrate systematically towards nations with large R & D spending. Our study cannot adjudicate on whether migration improves scientists' productivity, but we find that movers and stayers have identical h-index citations scores. Immigrants in the UK and US now win Nobel Prizes proportionately less often than earlier. US residents' h-indexes are relatively high. We describe a framework where a key role is played by low mobility costs in the modern world. Copyright © The Author(s). Journal compilation © Royal Economic Society 2009. Document type: Book
Abstract
We collect data on the movement and productivity of elite scientists. Their mobility is remarkable: nearly half of the world's most-cited physicists work outside their country [...]
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Alleine wohnen empirische befunde zu einer weit verbreiteten lebensform
G. Sturm

Collection of open chapters of books in transport research (2010). Vol. 2010, 40

Abstract
Die im Zuge des sozialen Wandels zu beobachtende Ausdifferenzierung von Lebens- und Wohnformen wird verbreitet als Ausdruck von Individualisierung und erweiterten Wahlmöglichkeiten gedeutet. Laut diesem Denkzusammenhang ist die Zunahme von Einpersonenhaushalten vor allem den großstädtischen Singles zuzuschreiben. Der Beitrag liefert - basierend auf Auswertungen der laufenden Bevölkerungsumfrage des BBSR - empirische Befunde zur Wohn- und Lebenssituation allein wohnender Frauen und Männer in Deutschland. Als theoretische Orientierung werden vier Charakteristika heutigen Wohnens von Hartmut Häußermann und Walter Siebel zugrunde gelegt. Document type: Part of book or chapter of book
Abstract
Die im Zuge des sozialen Wandels zu beobachtende Ausdifferenzierung von Lebens- und Wohnformen wird verbreitet als Ausdruck von Individualisierung und erweiterten Wahlmöglichkeiten [...]
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Air traffic control a local approach to the trajectory segmentation issue
J. Guerrero Madrid, J. García, J. Molina

Collection of open chapters of books in transport research (2010). Vol. 2010, 39

Abstract
Proceedings of: 23rd International Conference on Industrial, Engineering & Other Applications of Applied Intelligent Systems (IEA-AIE 2010) Córdoba-Spain, June 04-06, 2010 This paper presents a new approach for trajectory segmentation in the area of Air Traffic Control, as a basic tool for offline validation with recorded opportunity traffic data. Our approach uses local information to classify each measurement individually, constructing the final segments over these classified samples as the final solution of the process. This local classification is based on a domain transformation using motion models to identify the deviations at a local scale, as an alternative to other global approaches based on combinatorial analysis over the trajectory segmentation domain. This work was supported in part by Projects CICYT TIN2008-06742-C02-02/TSI, CICYT TEC2008-06732-C02-02/TEC, CAM CONTEXTS (S2009/TIC-1485) and DPS2008-07029-C02-02. Publicado Document type: Part of book or chapter of book
Abstract
Proceedings of: 23rd International Conference on Industrial, Engineering & Other Applications of Applied Intelligent Systems (IEA-AIE 2010) Córdoba-Spain, June 04-06, 2010 [...]
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Verkennende ecologische gebiedsvisie voor het leopoldkanaal en omgeving
A. Kerckvoorde, K. Decleer

Collection of open chapters of books in transport research (2009). Vol. 2009, 21

Abstract
Document type: Book
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Let it flow building mashups with data processing pipelines
B. Biörnstad, C. Pautasso

Collection of open chapters of books in transport research (2009). Vol. 2009, 20

Abstract
Mashups are a new kind of interactive Web application, built out of the composition of two or more existing Web service APIs and data sources. Whereas "pure" mashups are built relying entirely on the Web browser as a platform for integration at the presentation layer, this approach is not always feasible and part of the mashup integration logic must be deployed on the Web server instead. In the case study presented in this paper, we explore a novel approach to build mashups out of heterogeneous sources of streaming data. In particular, we introduce a layered mashup architecture, with a clear separation between the mashup user interface and the mashup integration logic run by a mashup engine. To do so, we show how to build a mashup application that displays in real time the location of visitors connecting to a Website. The integration logic feeding a map widget by processing the Web site logs is developed using a data flow model that connects a set of reusable and heterogeneous components into a data processing pipeline. We conduct a brief performance evaluation of the mashup showing that the pipeline introduces minimal delay and discuss several extensions of the mashup. Document type: Part of book or chapter of book
Abstract
Mashups are a new kind of interactive Web application, built out of the composition of two or more existing Web service APIs and data sources. Whereas "pure" mashups are built [...]
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Solar Energy
C. Fell, J. Hinkley, A. Imenes, W. Stein

Collection of open chapters of books in transport research (2010). Vol. 2010, 30

Abstract
This thesis is about Photovoltaic (PV) cells and its stresses in various directions by calculating the power generated using solar cells under different conditions to improve its efficiency. Our research studies found that using multi-junction cells with larger substrates can increase the efficiency to some extent which in practice is limited to 43 percent. The experiment was conducted using ten solar cells each with an area of 20.9?cm? ^2, where each cell gives 0.5 V and 0.4 A and a 1.25 ? resistor was used. The cells were connected in series. Once, the PV cells were fixed horizontally and the other time tested in tilted position under same outdoor condition. The purpose of testing PV cells was to investigate the efficiency under above mentioned conditions. The data collected from the readings was used in calculation, and we have obtained from the calculations that horizontally fixed cells gave 4.8 percent efficiency whereas tilted cells gave 6.6 percent efficiency. Hence, the ratio showed that fixed cells produced 37.5 percent more power compared to horizontally fixed cells. Our other experiment consisted of testing PV cells under different temperature conditions that was done using a freezer and an oven for temperature variation and a tungsten bulb was used as a light source. The purpose of performing this experiment was to investigate how the efficiency of PV cells is affected under extreme conditions. Part of our thesis was also including studies and analysis of produced energy by the solar panel installed on the roof of BTH building in Karlskrona, Sweden. The data consisted of energy produced from February up to August 2014. The investigation also included finding the highest produced energy during these months. We have found that the highest energy was generated on the 1st of July which was 12.86 kWh. Furthermore, we went deep into investigation of the 1st of July to know exactly which hour of that day the highest energy was produced. The data showed that the highest produced energy was at 12:19 and 13:19 which was 2.03 kWh. Ramzi: +46723231353, +966561993488 Zain Document type: Part of book or chapter of book
Abstract
This thesis is about Photovoltaic (PV) cells and its stresses in various directions by calculating the power generated using solar cells under different conditions to improve [...]
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Some observations on the air transport of animals
I. Diederiks-Verschoor

Collection of open chapters of books in transport research (2010). Vol. 2010, 28

Abstract
With the increase in air transport, the transport of animals has grown, too. According to the International Association for Transport Companies, more than 500,000 animals are transported by airlines annually. Problems are caused by inadequate cages, an absence of health certificates, differences in temperature, insufficient oxygen and bad treatment. The European Convention for Protection of Animals during International Transport is divided into two parts: general rules and special rules. The latter include items such as means of transport, the same sort of animals being together and no overcrowding. National rules also exist and may include special rules for animals which are taken into the cabin. The US Federal Aviation Administration (FAA) allows each airline to decide whether or not to allow a person to travel with a pet in the passenger cabin. The rules are similar to the above European Convention of 1968. Keywords: animals; federal aviation administration (FAA); international transpor Document type: Part of book or chapter of book
Abstract
With the increase in air transport, the transport of animals has grown, too. According to the International Association for Transport Companies, more than 500,000 animals [...]
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Evaluation of Automatically Extracted Landmarks for Future Driver Assistance Systems
C. Brenner, S. Hofmann

Collection of open chapters of books in transport research (2010). Vol. 2010, 27

Abstract
In the future, vehicles will gather more and more spatial information about their environment, using on-board sensors such as cameras and laser scanners. Using this data, e.g. for localization, requires highly accurate maps with a higher level of detail than provided by today's maps. Producing those maps can only be realized economically if the information is obtained fully automatically. It is our goal to investigate the creation of intermediate level maps containing geo-referenced landmarks, which are suitable for the specific purpose of localization. To evaluate this approach, we acquired a dense laser scan of a 22 km scene, using a mobile mapping system. From this scan, we automatically extracted pole-like structures, such as street and traffic lights, which form our pole database. To assess the accuracy, ground truth was obtained for a selected inner-city junction by a terrestrial survey. In order to evaluate the usefulness of this database for localization purposes, we obtained a second scan, using a robotic vehicle equipped with an automotive-grade laser scanner. We extracted poles from this scan as well and employed a local pole matching algorithm to improve the vehicle's position. Document type: Part of book or chapter of book
Abstract
In the future, vehicles will gather more and more spatial information about their environment, using on-board sensors such as cameras and laser scanners. Using this data, [...]
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Perceptions of risk and control understanding acceptance of advanced driver assistance systems
S. Joshi, T. Bellet, V. Bodard, A. Amditis

Collection of open chapters of books in transport research (2009). Vol. 2009, 18

Abstract
With a marked increase in advanced driver assistance systems (ADAS) being designed and deployed for cars, there is a logical emergence of studies that critically examine the influence these have on driver behavior and attitudes towards risk and safety. The research question addressed within this paper asks to what extent the level of perceived criticality or risk on the part of drivers influences their acceptance of advanced assistance. Document type: Part of book or chapter of book
Abstract
With a marked increase in advanced driver assistance systems (ADAS) being designed and deployed for cars, there is a logical emergence of studies that critically examine the [...]
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Jbig for printer pipelines a compression test
D. Ravì, T. Meccio, G. Messina, M. Guarnera

Collection of open chapters of books in transport research (2009). Vol. 2009, 17

Abstract
The proposed paper describes a compression test analysis of JBIG standard algorithm. The aim of such work is to proof the effectiveness of this standard for images acquired through scanners and processed into a printer pipeline. The main issue of printer pipelines is the necessity to use a memory buffer to store scanned images for multiple prints. This work demonstrates that for very large scales the buffer can be fixed using medium compression case, using multiple scans in case of uncommon random patterns. Document type: Part of book or chapter of book
Abstract
The proposed paper describes a compression test analysis of JBIG standard algorithm. The aim of such work is to proof the effectiveness of this standard for images acquired [...]
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Moving Object Segmentation Using Optical Flow and Depth Information
J. Klappstein, T. Vaudrey, C. Rabe, A. Wedel, R. Klette

Collection of open chapters of books in transport research (2009). Vol. 2009, 16

Abstract
This paper discusses the detection of moving objects (being a crucial part of driver assistance systems) using monocular or stereoscopic computer vision. In both cases, object detection is based on motion analysis of individually tracked image points (optical flow), providing a motion metric which corresponds to the likelihood that the tracked point is moving. Based on this metric, points are segmented into objects by employing a globally optimal graph-cut algorithm. Both approaches are comparatively evaluated using real-world vehicle image sequences. Document type: Part of book or chapter of book
Abstract
This paper discusses the detection of moving objects (being a crucial part of driver assistance systems) using monocular or stereoscopic computer vision. In both cases, object [...]
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Cause and effect in user interface development
E. Hvannberg

Collection of open chapters of books in transport research (2009). Vol. 2009, 14

Abstract
There is a lack of means of translating work products of elicitation to design and using results of evaluation as feedback to design. This paper lays the foundation of a model of evaluation to be built concurrently with the design activity. The evaluation model describes the implications which work models have on design and records the cause/effect relationship between design and the problem domain. The paper presents two case studies from air traffic control that are meant to motivate the need for such an evaluation model and serve as input to its design. Document type: Part of book or chapter of book
Abstract
There is a lack of means of translating work products of elicitation to design and using results of evaluation as feedback to design. This paper lays the foundation of a model [...]
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Lock in effects of road expansion on co2 emissions results from a core periphery model of beijing
A. Anas, G. Timilsina

Collection of open chapters of books in transport research (2009). Vol. 2009, 11

Abstract
In the urban planning literature, it is frequently explicitly asserted or strongly implied that ongoing urban sprawl and decentralization can lead to development patterns that are unsustainable in the long run. One manifestation of such an outcome is that if extensive road investments occur, urban sprawl and decentralization are advanced and locked-in, making subsequent investments in public transit less effective in reducing vehicle kilometers traveled by car, gasoline use and carbon dioxide emissions. Using a simple core-periphery model of Beijing, the authors numerically assess this effect. The analysis confirms that improving the transit travel time in Beijing?s core would reduce the city?s overall carbon dioxide emissions, whereas the opposite would be the case if peripheral road capacity were expanded. This effect is robust to perturbations in the model?s calibrated parameters. In particular, the effect persists for a wide range of assumptions about how location choice depends on travel time and a wide range of assumptions about other aspects of consumer preferences. Document type: Book
Abstract
In the urban planning literature, it is frequently explicitly asserted or strongly implied that ongoing urban sprawl and decentralization can lead to development patterns [...]
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Computing Differential Invariants of Hybrid Systems as Fixedpoints
A. Platzer, E. Clarke

Collection of open chapters of books in transport research (2009). Vol. 2009, 10

Abstract
We introduce a fixedpoint algorithm for verifying safety properties of hybrid systems with differential equations whose right-hand sides are polynomials in the state variables. In order to verify nontrivial systems without solving their differential equations and without numerical errors, we use a continuous generalization of induction, for which our algorithm computes the required differential invariants. As a means for combining local differential invariants into global system invariants in a sound way, our fixedpoint algorithm works with a compositional verification logic for hybrid systems. With this compositional approach we exploit locality in system designs. To improve the verification power, we further introduce a saturation procedure that refines the system dynamics successively with differential invariants until safety becomes provable. By complementing our symbolic verification algorithm with a robust version of numerical falsification, we obtain a fast and sound verification procedure. We verify roundabout maneuvers in air traffic management and collision avoidance in train control and car control. Document type: Part of book or chapter of book
Abstract
We introduce a fixedpoint algorithm for verifying safety properties of hybrid systems with differential equations whose right-hand sides are polynomials in the state variables. [...]
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Internationale Kompetenzen in der Berufsbildung: Stand der Wissenschaft und praktische Anforderungen
P. Wordelmann

Collection of open chapters of books in transport research (2010). Vol. 2010, 15

Abstract
In dieser Einleitung wird ein Überblick über den Stand der Wissenschaft sowie die praktischen Anforderungen im Hinblick auf internationale Kompetenzen in der Berufsbildung gegeben: Zunächst werden unter der Perspektive von der Exportorientierung über den Binnenmarkt zur Globalisierung die Bedarfsseiten der internationalen Qualifikationen sowie die Feststellung von internationalen Kompetenzen und ihre Verankerung in den Ausbildungsvorschriften beleuchtet. Danach wird auf den Erwerb internationaler Kompetenzen durch transnationale Mobilität insbesondere in Form von Auslandspraktika eingegangen. Zuletzt werden die Forschung über internationale Berufsbildung sowie die internationale berufliche Handlungskompetenz thematisiert. (DIPF/paul) Document type: Part of book or chapter of book
Abstract
In dieser Einleitung wird ein Überblick über den Stand der Wissenschaft sowie die praktischen Anforderungen im Hinblick auf internationale Kompetenzen in der Berufsbildung [...]
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Environmental costs account a base for measuring sustainability in transport plans
A. Monzón de Cáceres, Á. Fernández Heredia, P. Jordá Lope

Collection of open chapters of books in transport research (2009). Vol. 2009, 9

Abstract
Each city need to develop sustainable transport plans according to its future developments. This means identifying the best policy package of transport measures that could produce more sustainable future scenarios: lowest environmental impact, but also better social standards and at minimum cost. To that end, it is necessary to measure the environmental and social costs of each alternative transport mode. This paper proposes a methodology to calculate those costs in different city contexts: city centre and metropolitan suburbs. It provides a measure of the following environmental costs: pollution, noise, green house gasses and land taken. Then the social costs as congestion and accident costs. These two cost categories are calculated for each mean of transport: metro, bus, private car and taxi. The methodology has been applied to Madrid Region through modeling its mobility demand in 2004. The outputs are costs per passenger-km in each mode and Area: city centre and metropolitan ring. Therefore it is possible to assign monetary costs to environmental and social costs of each transport option; for example, car environmental costs are four times higher than buses on average, but it differs a lot from city centre to outskirt areas. Finally, some guidelines can be extracted to develop a more sustainable transport policy for Madrid Region. No data (2010) UEM Document type: Part of book or chapter of book
Abstract
Each city need to develop sustainable transport plans according to its future developments. This means identifying the best policy package of transport measures that could [...]
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Pricing externalities from passenger transportation in mexico city
I. Parry, G. Timilsina

Collection of open chapters of books in transport research (2009). Vol. 2009, 5

Abstract
The Mexico City Metropolitan Area has been suffering severely from transportation externalities such as accidents, air pollution, and traffic congestion. This study examines pricing instruments to reduce these externalities using an analytical and numerical model. The study shows that the optimal levels of a gasoline tax and a congestion toll on automobiles could generate social benefits, measured in terms of welfare gain, of US$132 and US$109 per capita, respectively, through the reduction of externalities. The largest component of the welfare gains comes from reduced congestion, followed by local air pollution reduction. The optimal toll and tax would, however, double the cost of driving and could be politically sensitive. Still, more than half of those welfare gains could be obtained through a more modest tax or toll, equivalent to $1 per gallon of gasoline. The welfare gains from reforming the pricing of public transportation are small relative to those from reforming the taxation of automobiles. Although the choice among travel modes depends on specific circumstances, in the absence of road travel pricing that accounts for externalities, there will be potential for higher investment in roads relative to mass transit. Given the rapidly increasing demand for transportation infrastructure in Mexico City, careful efforts should be made to include the full social costs of travel in evaluating alternative infrastructure investments. Document type: Book
Abstract
The Mexico City Metropolitan Area has been suffering severely from transportation externalities such as accidents, air pollution, and traffic congestion. This study examines [...]
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A grounded theory approach towards conceptualizing CIS for heterogeneous work communities
N. Selvaraj, B. Fields

Collection of open chapters of books in transport research (2009). Vol. 2009, 4

Abstract
The notion of Common Information Space (CIS) is an area that has been gaining attention in the field of Computer Supported Cooperative Work (CSCW) over the last few years. This paper discusses one aspect of the investigation being undertaken to develop the conceptualization of CIS pertaining to heterogeneous work communities. This is based on empirical study of collaborative decision making involving different work communities in an airport of the air traffic control setting. The theory development is founded on the Grounded Theory approach. We present some of the findings of the ongoing analysis. In particular we discuss how the Grounded Theory methodological process has been adapted to this investigation by presenting illustrations of emergent theory development at the theoretical coding phase of the process. Document type: Part of book or chapter of book
Abstract
The notion of Common Information Space (CIS) is an area that has been gaining attention in the field of Computer Supported Cooperative Work (CSCW) over the last few years. [...]
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How to Improve the Capture of Urban Goods Movement Data?
D. Patier, J. Routhier

Collection of open chapters of books in transport research (2009). Vol. 2009, 3

Abstract
Paper presented at the Session: Urban goods surveys; The surveys specifically focused on the thorough knowledge of urban freight transport appeared about ten years ago. The local problematic of goods transport at local level was partially taken into account by the city planners and by the researchers: until recent years, the integration of goods transport in the total urban flows models was estimated applying a multiplying factor to car traffic. Delivering goods was not considered like a concern."br /"Because of the quick growth of car traffic in the cities, the main stakes changed too: the fight against traffic congestion, the management of the lack of space (shipment consolidation and storage), the attempts to reduce local environmental impacts and global externalities (energy saving, reduction of greenhouse gas emissions), and economic valuation of city centres (under the pressure of a slowed down economic growth)."br /"All these changes were taking place in a context in which available rooms for manoeuvre were limited by factors such as congestion, concerns about the quality of urban life and budget restriction. It resulted in a growing unease on the freight transport industry and the city authorities, the latter having little or no data, methods and references in order to elaborate a satisfactory policy framework. Document type: Part of book or chapter of book
Abstract
Paper presented at the Session: Urban goods surveys; The surveys specifically focused on the thorough knowledge of urban freight transport appeared about ten years ago. [...]
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Road projects cost benefit analysis scenario analysis of the effect of varying inputs
K. Tsunokawa

Collection of open chapters of books in transport research (2010). Vol. 2010, 7

Abstract
Six projects from six countries were selected as the cases for detailed analysis in this study. They are from Argentina, Botswana, India, Kenya, Lao PDR and Paraguay, representing a wide range of geographical distribution. Also, the extent of the effect of economic downturn which these countries experienced ranges a wide variety. In an economic downturn, uncertainties increase with many inputs of road projects Cost Benefit Analysis (CBA), including fuel prices, levels of demand, investment costs and maintenance availability. Also, important parameters of project evaluation such as discount rate and value of time need to be more carefully scrutinized. Therefore, it is very important for the developing countries to have good understanding about the effects of the variability of these inputs/parameters on project viability and the ranking of road investments. It is a role of the developing agencies to conduct a systematic analysis of these effects and disseminate the findings and knowledge obtained. The objective of the study is to obtain insights regarding the effects of varying inputs and parameters on the viability of road projects through case studies using Highway Development and Management Model (HDM-4), thereby to facilitate the formulation and implementation of road projects that increase the welfare of the society under the environment of increased uncertainty in an economic downturn. The results of the study will be summarized in a transport note as a discrete knowledge product and disseminated among various stakeholders including developing agencies staff, government officials and donor communities. To assess the effects of increased uncertainty with inputs of cost benefit analysis on the economic viability of road projects, this study first investigated the range of variability of the inputs for the six selected projects/countries. It was found that the variability ranges differ by country reflecting the degree of decrease in transport demand and relative change in factor prices due to economic downturn. Document type: Book
Abstract
Six projects from six countries were selected as the cases for detailed analysis in this study. They are from Argentina, Botswana, India, Kenya, Lao PDR and Paraguay, representing [...]
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Institutional Development and Good Governance in the Highway Sector
A. Bandyopadhyay, N. Stankevich

Collection of open chapters of books in transport research (2010). Vol. 2010, 6

Abstract
The World Bank financed the Gujarat State Highway Project (GSHP) during 2001-07. The project development objective was to enhance the capacity of the Government of Gujarat (GOG) for effective and efficient planning and management of road infrastructure, while concurrently maximizing existing road infrastructure asset productivity through priority investments and increased maintenance funding. The project not only achieved its objective and targets successfully, but also was implemented with a significant cost reduction (about 23 percent). The GSHP resulted in a reduction in the backlog of major maintenance and an improved network to meet rapidly growing transport demand in the state. The project had the unique distinction of no contract disputes, a rarity among the highway development projects in India. The project also set best practices in developing and managing a very comprehensive asset management system, state of the art quality assurance framework and a very comprehensive training and capacity building program. The annual road sector allocation has grown from USD 30 million in 1995-1996 to an impressive USD 610 million in 2010-11, currently the second largest among all the Indian states. This study attempts to identify the key elements of the Gujarat road sector reforms and explores whether and, if so, how such reforms can be replicated across other Indian states and possibly even in other countries in the region. Document type: Book
Abstract
The World Bank financed the Gujarat State Highway Project (GSHP) during 2001-07. The project development objective was to enhance the capacity of the Government of Gujarat [...]
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Die Europäisierung der Berufsbildung und ihre Auswirkungen auf die deutsche Trägerlandschaft
H. Loebe

Collection of open chapters of books in transport research (2010). Vol. 2010, 5

Abstract
Der Autor stellt zunächst einige allgemeine Überlegungen zum Thema „Mobilität und berufliche Bildung“ sowie zur Europäisierung und Internationalisierung der Berufsbildung an. Dabei nennt er insbesondere den EQF (den Europäischen Qualifikationsrahmen) und das ECVET (das Europäische Credit-System für die Berufsbildung) als Instrumente und Maßnahmen, mehr Transparenz und Vergleichbarkeit, mehr Mobilität und mehr Durchlässigkeit in den und zwischen den Bildungssystemen durchzusetzen. Anschließend geht er zu den Folgerungen über, die sich daraus für Anbieter beruflicher Bildung in Deutschland ergeben. Exemplarisch zeigt er dabei an einigen Aktivitäten der bbw Group auf, was das für den Bereich der beruflichen Bildung konkret bedeuten kann. (DIPF/ ssch) Document type: Part of book or chapter of book
Abstract
Der Autor stellt zunächst einige allgemeine Überlegungen zum Thema „Mobilität und berufliche Bildung“ sowie zur Europäisierung und Internationalisierung der Berufsbildung [...]
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Contingency Plans for Air Traffic Management
K. Blomdahl, P. Flener, J. Pearson

Collection of open chapters of books in transport research (2010). Vol. 2010, 2

Abstract
We present two heuristics based on constraint technology that solve the problem of generating air traffic management contingency plans, which are used in the case of a catastrophic infrastructure failure within EUROCONTROL, the European Organisation for the Safety of Air Navigation. Of the heuristics presented, one is based on constraint-based local search and tabu search, and the other one is a constraint programming and large neighbourhood search hybrid algorithm. The heuristics show that it is feasible to automate the development of contingency plans, which is currently done by human experts; this is desirable for several reasons, for example it would allow the contingency plans to be generated with an increased frequency. The generated plans were evaluated, by EUROCONTROL, to be at least as good as the human-made ones. Document type: Part of book or chapter of book
Abstract
We present two heuristics based on constraint technology that solve the problem of generating air traffic management contingency plans, which are used in the case of a catastrophic [...]
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Olgierd Cecil Zienkiewicz obituary
M. Kleiber, E. Oñate

Archives of Comp. Meths. Engng. (2009). Vol. 16, pp. 465
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Control of the finite element discretization error during the convergence of structural shape optimization algorithms
G. Bugeda, J. Ródenas, J. Albelda, E. Oñate

Int. J. Simul. Multidisci. Des. Optim. (2009). Vol. 3 (3), pp. 363-369

Abstract
This work analyzes the influence of the discretization error contained in the Finite Element (FE) analyses of each design configuration proposed by structural shape optimization algorithms over the behaviour of the algorithm. If the FE analyses are not accurate enough, the final solution will neither be optimal nor satisfy the constraints. The need for the use of adaptive FE analysis techniques in shape optimum design will be shown. The paper also proposes the use of the algorithm described in [1] in order to reduce the computational cost associated to the adaptive FE analysis of each geometrical configuration when evolutive optimization algorithms are used.
Abstract
This work analyzes the influence of the discretization error contained in the Finite Element (FE) analyses of each design configuration proposed by structural shape optimization [...]
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Guaranteed energy error bounds for the Poisson equation using a flux-free approach: solving the local problems in subdomains
N. Parés, H. Santos, P. Diez

Int. J. Numer. Meth. Engng. (2009). Vol. 79 (10), pp. 1203-1244

Abstract
A method to compute guaranteed upper bounds for the energy norm of the exact error in the finite element solution of the Poisson equation is presented. The bounds are guaranteed for any finite element mesh however coarse it may be, not just in the asymptotic regime. The bounds are constructed by employing a subdomain based a posteriori error estimate which yields self-equilibrated residual loads in stars (patches of elements). The proposed approach is an alternative to standard equilibrated residual methods providing sharper bounds. The use of a flux-free error estimator improves the effectivities of the upper bounds for the energy while retaining the certainty of the bounds.
Abstract
A method to compute guaranteed upper bounds for the energy norm of the exact error in the finite element solution of the Poisson equation is presented. The bounds are guaranteed [...]
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Exact bounds for linear outputs of the advection-diffusion-reaction equation using flux-free error estimates
N. Parés, P. Diez, A. Huerta

Journal on Scientific Computing (SIAM) (2009). Vol. 31 (4), pp. 3064-3089

Abstract
The paper introduces a methodology to compute strict upper and lower bounds for linear-functional outputs of the exact solutions of the advection-reaction-diffusion equation. The proposed approach is an alternative to the standard residual type estimators (hybrid-flux), circumventing the need of flux-equilibration following a fluxfree error estimation strategy. The presented estimator provides sharper estimates than the ones provided by both the standard hybrid-flux techniques and other flux-free techniques.
Abstract
The paper introduces a methodology to compute strict upper and lower bounds for linear-functional outputs of the exact solutions of the advection-reaction-diffusion equation. [...]
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Hierarchical X-FEM for n-phase flow (n>2)
S. Zlotnik, P. Diez

Comput. Methods Appl. Mech. Engrg., (2009). Vol. 198 (30-32), pp. 2329-2338

Abstract
The eXtended Finite Element Method (X-FEM) has been successfully used in two-phase flow problems involving a moving interface. In order to simulate problems involving more than two phases, the X-FEM has to be further eXtended. The proposed approach is presented in the case of a quasi-static Stokes n-phase flow and it is based on using an ordered collection of level set functions to describe the location of the phases. A level set hierarchy allows describing triple junctions avoiding overlapping or “voids” between materials. Moreover, an enriched solution accounting for several simultaneous phases inside one element is proposed. The interpolation functions corresponding to the enriched degrees of freedom require redefining the associated ridge function accounting for all the level sets. The computational implementation of this scheme involves calculating integrals in elements having several materials inside. An adaptive quadrature accounting for the interfaces locations is proposed to accurately compute these integrals. Examples of the hierarchical X-FEM approach are given for a n-phase Stokes problem in 2 and 3 dimensions.
Abstract
The eXtended Finite Element Method (X-FEM) has been successfully used in two-phase flow problems involving a moving interface. In order to simulate problems involving more [...]
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Strict error bounds for linear solid mechanics problems using a subdomain-based flux-free method
R. Cottereau, P. Diez, A. Huerta

Computational Mechanics (2009). Vol. 44 (4), pp. 533-547

Abstract
We discuss, in this paper, a flux-free method for the computation of strict upper bounds of the energy norm of the error in a Finite Element (FE) computation. The bounds are strict in the sense that they refer to the difference between the displacement computed on the FE mesh and the exact displacement, solution of the continuous equations, rather than to the difference between the displacements computed on two FE meshes, one coarse and one refined. This method is based on the resolution of a series of local problems on patches of elements and does not require the resolution of a previous problem of flux equilibration, as happens with other methods. The paper concentrates more specifically on linear solid mechanics issues, and on the assessment of the energy norm of the error, seen as a necessary tool for the estimation of the error in arbitrary quantities of interest (linear functional outputs). Applications in both 2D and 3D are presented
Abstract
We discuss, in this paper, a flux-free method for the computation of strict upper bounds of the energy norm of the error in a Finite Element (FE) computation. The bounds are [...]
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A simple strategy to assess the error in the numerical wave number of the finite element solution of the Helmholtz equation
L. Steffens, P. Diez

Comput. Methods Appl. Mech. Engrg., (2009). Vol. 198 (15-16), pp. 1389-1400

Abstract
The standard approach for goal oriented error estimation and adaptivity uses an error representation via an adjoint problem, based on the linear functional output representing the quantity of interest. For the assessment of the error in the approximation of the wave number for the Helmholtz problem (also referred to as dispersion or pollution error), this strategy cannot be applied. This is because there is no linear extractor producing the wave number from the solution of the acoustic problem. Moreover, in this context, the error assessment paradigm is reverted in the sense that the exact value of the wave number, κ, is known (it is part of the problem data) and the effort produced in the error assessment technique aims at obtaining the numerical wave number, κH, as a postprocess of the numerical solution, uH. The strategy introduced in this paper is based on the ideas used in the a priori analysis. A modified equation corresponding to a modified wave number κm is introduced. Then, the value of κm such that the modified problem better accommodates the numerical solution uH is taken as the estimate of the numerical wave number κH. Thus, both global and local versions of the error estimator are proposed. The obtained estimates of the dispersion error match the a priori predicted dispersion error and, in academical examples, the actual values of the error in the wave number.
Abstract
The standard approach for goal oriented error estimation and adaptivity uses an error representation via an adjoint problem, based on the linear functional output representing [...]
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The fixed‐mesh ALE approach applied to solid mechanics and fluid–structure interaction problems
J. Baiges, R. Codina

Int. J. Numer. Meth. Engng. (2009). Vol. 81 (12), pp. 1529-1557

Abstract
In this paper we propose a method to solve Solid Mechanics and fluid–structure interaction problems using always a fixed background mesh for the spatial discretization. The main feature of the method is that it properly accounts for the advection of information as the domain boundary evolves. To achieve this, we use an Arbitrary Lagrangian–Eulerian (ALE) framework, the distinctive characteristic being that at each time step results are projected onto a fixed, background mesh. For solid mechanics problems subject to large strains, the fixed‐mesh (FM)‐ALE method avoids the element stretching found in fully Lagrangian approaches. For FSI problems, FM‐ALE allows for the use of a single background mesh to solve both the fluid and the structure.
Abstract
In this paper we propose a method to solve Solid Mechanics and fluid–structure interaction problems using always a fixed background mesh for the spatial discretization. [...]
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Approximate imposition of boundary conditions in immersed boundary methods
R. Codina, J. Baiges

Int. J. Numer. Meth. Engng. (2009). Vol. 80 (11), pp. 1379-1405

Abstract
We analyze several possibilities to prescribe boundary conditions in the context of immersed boundary methods. As basic approximation technique we consider the finite element method with a mesh that does not match the boundary of the computational domain, and therefore Dirichlet boundary conditions need to be prescribed in an approximate way. As starting variational approach we consider Nitsche's methods, and we then move to two options that yield non‐symmetric problems but that turned out to be robust and efficient. The essential idea is to use the degrees of freedom of certain nodes of the finite element mesh to minimize the difference between the exact and the approximated boundary condition
Abstract
We analyze several possibilities to prescribe boundary conditions in the context of immersed boundary methods. As basic approximation technique we consider the finite element [...]
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Computational aeroacoustics of viscous low speed flows using subgrid scale finite element methods
O. Guasch, R. Codina

Journal of Computational Acoustics (2009). Vol. 17 (3), pp. 309-330

Abstract
A methodology to perform computational aeroacoustics (CAA) of viscous low speed flows in the framework of stabilized finite element methods is presented. A hybrid CAA procedure is followed that makes use of Lighthill's acoustic analogy in the frequency domain. The procedure has been conceptually divided into three steps. In the first one, the incompressible Navier–Stokes equations are solved to obtain the flow velocity field. In the second step, Lighthill's acoustic source term is computed from this velocity field and then Fourier transformed to the frequency domain. Finally, the acoustic pressure field is obtained by solving the corresponding inhomogeneous Helmholtz equation. All equations in the formulation are solved using subgrid scale stabilized finite element methods. The main ideas of the subgrid scale numerical strategy are outlined and its benefits when compared to the Galerkin approach are described. As numerical examples, the aerodynamic noise generated by flow past a two-dimensional cylinder and by flow past two cylinders in parallel arrangement are addressed.
Abstract
A methodology to perform computational aeroacoustics (CAA) of viscous low speed flows in the framework of stabilized finite element methods is presented. A hybrid CAA procedure [...]
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Mathematical models for thermally coupled low speed flows
J. Principe, R. Codina

Adv. Theor. Appl. Mech. (2009). Vol. 2 (2), pp. 93-112

Abstract
In this paper we review and clarify some aspects of the asymptotic analysis of the compressible Navier Stokes equations in the low Mach number limit. In the absence of heat exchange (the isentropic regime) this limit is well understood and rigorous results are available. When heat exchange is considered different simplified models can be obtained, the most famous being the Boussinesq approximation. Here a unified formal justification of these models is presented, paying special attention to the relation between the low Mach number and the Boussinesq approximations. Precise conditions for their validity are given for classical problems in bounded domains.
Abstract
In this paper we review and clarify some aspects of the asymptotic analysis of the compressible Navier Stokes equations in the low Mach number limit. In the absence of heat [...]
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Unified Stabilized Finite Element Formulations for the Stokes and the Darcy Problems
S. Badia, R. Codina

SIAM J. Numer. Anal. (2009). Vol. 47 (3), pp. 1971-2000

Abstract
In this paper we propose stabilized finite element methods for both Stokes' and Darcy's problems that accommodate any interpolation of velocities and pressures. Apart from the interest of this fact, the important issue is that we are able to deal with both problems at the same time, in a completely unified manner, in spite of the fact that the functional setting is different. Concerning the stabilization formulation, we discuss the effect of the choice of the length scale appearing in the expression of the stabilization parameters, both in what refers to stability and to accuracy. This choice is shown to be crucial in the case of Darcy's problem. As an additional feature of this work, we treat two types of stabilized formulations, showing that they have a very similar behavior
Abstract
In this paper we propose stabilized finite element methods for both Stokes' and Darcy's problems that accommodate any interpolation of velocities and pressures. Apart [...]
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A numerical approximation of the thermal coupling of fluids and solids
J. Principe, R. Codina

Int. J. Numer. Meth. Fluids (2009). Vol. 59 (11), pp. 1181-1201

Abstract
In this article we analyze the problem of the thermal coupling of fluids and solids through a common interface. We state the global thermal problem in the whole domain, including the fluid part and the solid part. This global thermal problem presents discontinuous physical properties that depend on the solution of auxiliary problems on each part of the domain (a fluid flow problem and a solid state problem). We present a domain decomposition strategy to iteratively solve problems posed in both subdomains and discuss some implementation aspects of the algorithm. This domain decomposition framework is also used to revisit the use of wall function approaches used in this context.
Abstract
In this article we analyze the problem of the thermal coupling of fluids and solids through a common interface. We state the global thermal problem in the whole domain, including [...]
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On a multiscale approach to the transient Stokes problem: Dynamic subscales and anisotropic space–time discretization
S. Badia, R. Codina

Applied Mathematics and Computation (2009). Vol. 207 (2), pp. 415-433

Abstract
In this article, we analyze some residual-based stabilization techniques for the transient Stokes problem when considering anisotropic time–space discretizations. We define an anisotropic time–space discretization as a family of time–space partitions that does not satisfy the condition h2⩽Cδt with C uniform with respect to h and δt. Standard residual-based stabilization techniques are motivated by a multiscale approach, approximating the effect of the subscales onto the large scales. One of the approximations is to consider the subscales quasi-static (neglecting their time derivative). It is well known that these techniques are unstable for anisotropic time–space discretizations. We show that the use of dynamic subscales (where the subscales time derivatives are not neglected) solves the problem, and prove optimal convergence and stability results that are valid for anisotropic time–space discretizations. Also the improvements related to the use of orthogonal subscales are addressed.
Abstract
In this article, we analyze some residual-based stabilization techniques for the transient Stokes problem when considering anisotropic time–space discretizations. [...]
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The fixed-mesh ALE approach for the numerical approximation of flows in moving domains
R. Codina, G. Houzeaux, H. Coppola-Owen, J. Baiges

Journal of Computational Physics (2009). Vol. 228 (5), pp. 1591-1611

Abstract
In this paper we propose a method to approximate flow problems in moving domains using always a given grid for the spatial discretization, and therefore the formulation to be presented falls within the category of fixed-grid methods. Even though the imposition of boundary conditions is a key ingredient that is very often used to classify the fixed-grid method, our approach can be applied together with any technique to impose approximately boundary conditions, although we also describe the one we actually favor. Our main concern is to properly account for the advection of information as the domain boundary evolves. To achieve this, we use an arbitrary Lagrangian–Eulerian framework, the distinctive feature being that at each time step results are projected onto a fixed, background mesh, that is where the problem is actually solved.
Abstract
In this paper we propose a method to approximate flow problems in moving domains using always a given grid for the spatial discretization, and therefore the formulation [...]
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Finite element approximation of the three field formulation of the Stokes problem using arbitrary interpolations
R. Codina

SIAM J. Numer. Anal. (2009). Vol. 47 (1), pp. 699-718

Abstract
The stress-displacement-pressure formulation of the elasticity problem may suffer from two types of numerical instabilities related to the finite element interpolation of the unknowns. The first is the classical pressure instability that occurs when the solid is incompressible, whereas the second is the lack of stability in the stresses. To overcome these instabilities, there are two options. The first is to use different interpolation for all the unknowns satisfying two inf-sup conditions. Whereas there are several displacement-pressure interpolations that render the pressure stable, less possibilities are known for the stress interpolation. The second option is to use a stabilized finite element formulation instead of the plain Galerkin approach. If this formulation is properly designed, it is possible to use arbitrary interpolation for all the unknowns. The purpose of this paper is precisely to present one of such formulations. In particular, it is based on the decomposition of the unknowns into their finite element component and a subscale, which will be approximated and whose goal is to yield a stable formulation. A singular feature of the method to be presented is that the subscales will be considered orthogonal to the finite element space. We describe the design of the formulation and present the results of its numerical analysis.
Abstract
The stress-displacement-pressure formulation of the elasticity problem may suffer from two types of numerical instabilities related to the finite element interpolation of [...]
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Subscales on the element boundaries in the variational two-scale finite element method
R. Codina, J. Principe, J. Baiges

Comput. Methods Appl. Mech. Engrg., (2009). Vol. 198 (5-8), pp. 838-852

Abstract
In this paper, we introduce a way to approximate the subscales on the boundaries of the elements in a variational two-scale finite element approximation to flow problems. The key idea is that the subscales on the element boundaries must be such that the transmission conditions for the unknown, split as its finite element contribution and the subscale, hold. In particular, we consider the scalar convection–diffusion–reaction equation, the Stokes problem and Darcy’s problem. For these problems the transmission conditions are the continuity of the unknown and its fluxes through element boundaries. The former is automatically achieved by introducing a single valued subscale on the boundaries (for the conforming approximations we consider), whereas the latter provides the effective condition for approximating these values. The final result is that the subscale on the interelement boundaries must be proportional to the jump of the flux of the finite element component and the average of the subscale calculated in the element interiors.
Abstract
In this paper, we introduce a way to approximate the subscales on the boundaries of the elements in a variational two-scale finite element approximation to flow problems. [...]
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La ciencia a l'enginyeria. El llegat de l'école polytechnique
X. Oliver

(2009). Research Report, Nº PI338
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Size effect and localization in J2 plasticity
M. Cervera, M. Chiumenti

(2009). Research Report, Nº PI331

Abstract
This paper studies the phenomenon of structural size effect and strain localization in J2 plasticity. Size effect is here understood as the change in the response of a given structure when the spatial dimensions are scaled up or down while the geometry and other relevant properties of the structure are preserved. The work exploits the advantages of the mixed displacement–pressure formulation in incompressible or quasi-incompressible situations. Elasto-J2-plastic constitutive behaviour with regularized softening is considered. Stability issues are discussed to ensure existence and uniqueness of the solution of the corresponding discrete finite element formulation. Numerical examples show that the formulation derived is able to solve a wide range of structural scales, including real life engineering applications. The results obtained do not suffer from spurious mesh dependence. Furthermore, the formulation includes the classical theories of perfect plasticity and linear fracture mechanics as limit cases.
Abstract
This paper studies the phenomenon of structural size effect and strain localization in J2 plasticity. Size effect is here understood as the change in the response of a given [...]
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Fuel cells state of the art
A. Jarauta, J. Pons Prats

(2009). Research Report, Nº PI340
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Las ingenierias: Unas profesiones de largo recorrido
B. Suarez

(2009). Research Report, Nº PI339
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A finite point method to solve shallow water equations.
C. Buachart, E. Ortega, E. Oñate

(2009). Research Report, Nº PI337
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Optimizing rock cutting through computer simulation
J. Rojek, E. Oñate, C. Labra, H. Kazal, J. Akerman

(2009). Research Report, Nº PI336

Abstract
This paper presents an original thermomechanical model of rock cutting with evaluation of tool wear. The model has been developed within the framework of the discrete element method, which is a suitable numerical method to study problems of multiple material fractures likes those of rock cutting. The paper presents brief overview of the theoretical formulation, calibration of the discrete element model, and a number of numerical results obtained in simulation of rock cutting processes typical for underground excavation, using both roadheaders and TBMs.
Abstract
This paper presents an original thermomechanical model of rock cutting with evaluation of tool wear. The model has been developed within the framework of the discrete element [...]
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A neural networks approach to aerofoil noise prediction
K. Lau, R. López, E. Oñate

(2009). Research Report, Nº PI335

Abstract
A neural network noise prediction model for a turbulent boundary layer noise mechanism has been created using a feed forward multilayer perceptron and a noise spectrum database collected from a family of NACA 0012 areofoils. The results of the neural network model were compared against the Brooks model and it was found that the quality of the prediction was improved was improved over the entire range of the data. The model was also validated against experimental data not utilized the training of the neural, with positive results.
Abstract
A neural network noise prediction model for a turbulent boundary layer noise mechanism has been created using a feed forward multilayer perceptron and a noise spectrum database [...]
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Melting and spread of polymer in fire with the particle finite element method
E. Oñate, R. Rossi, K. Butler, S. Idelsohn

(2009). Research Report, Nº PI333

Abstract
A new computational procedure for analysis of the melting and flame spread of polymers under fire conditions is presented. The method, termed Particle Finite Element Method (PFEM), combines concepts from particle-based techniques with those of the standard finite element method (FEM). The key feature of the PFEM is the use of an updated Lagrangian description to model the motion of nodes (particles) in the thermoplastic material. Nodes are viewed as material points which can freely move and even separate from the main analysis domain representing, for instance, the effect of melting and dripping of polymer particles. A mesh connects the nodes defining the discretized domain where the governing equations are solved as in the standard FEM. An incremental iterative scheme for the solution of the nonlinear transient coupled thermal-flow problem, including loss of mass by gasification, is used. Examples of the possibilities of the PFEM for the modelling and simulation of the melting and flame spread of polymers under different fire conditions are described. Numerical results are compared with experimental data provided by NIST.
Abstract
A new computational procedure for analysis of the melting and flame spread of polymers under fire conditions is presented. The method, termed Particle Finite Element Method [...]
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A numerical investigation of wind tunnel model deformations caused by the twin-sting support system
R. Flores, E. Ortega, E. Oñate

(2009). Research Report, Nº PI334

Abstract
This work presents a wing deformation analysis of a twin-sting-mounted commercial aircraft model. Twin-sting arrangements minimize flow disturbances around the model fuselage and tail; on the other hand, they cause important changes in the flow field around the wing and also increase aerodynamic interference at the wing and aeroelastic effects on the wing. In some cases, these effects can alter the normal downwash developed behind the wing, modifying the flow pattern at the tail. Consequently, when tail aerodynamics is a major concern, this kind of support interference should be carefully evaluated. The methodology developed in this work employs an unstructured FEM-based flow solver for computing aerodynamic loads. These loads are then transferred to a finite element structural model in order to assess the geometrical deformation of the wing caused by torsional moment exerted by supporting mechanism. The analysis described involves three different twin-sting support configurations taking into account angle of attack variations and Mach numbers spanning from subsonic of high transonic ranges.
Abstract
This work presents a wing deformation analysis of a twin-sting-mounted commercial aircraft model. Twin-sting arrangements minimize flow disturbances around the model fuselage [...]
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New computational challenges in fluid-structure interactions problems
S. Idelsohn, E. Oñate, R. Rossi, J. Marti, F. Del Pin

(2009). ECCOMAS Multidisciplinary Jubilee Symposium, J. Eberhardsteiner, Ch. Hellmich, H. Mang and J. Périaux (Eds.)

Abstract
In this paper the so-called added-mass effect is investigated from a different point of view of previous publications. The monolithic fluid structure problem is partitioned using a static condensation of the velocity terms. Following this procedure the classical stabilized projection method for incompressible fluid flows is introduced. The procedure allows obtaining a new pressure segregated scheme for fluid-structure interaction problems which has good convergent characteristics even for biomechanical application, where the added mass effect is strong. The procedure reveals its power when it is shown that the same projection technique must be implemented in staggered FSI methods.
Abstract
In this paper the so-called added-mass effect is investigated from a different point of view of previous publications. The monolithic fluid structure problem is partitioned [...]
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Wireless sensor networks for strain monitoring during steel bridges launching
R. Chacón, F. Guzmán, E. Mirabell, E. Real, E. Oñate

Structural Health Monitoring (2009). Vol. 8 (3), pp. 195-205

Abstract
n this paper, an experimental test performed on a hybrid steel plate girder was subjected to concentrated loads at the end of an unstiffened panel is presented. This load was intended to produce a typical reaction of the piers while launching steel girders in bridges. In this test, strain measurements were taken with conventional pre-wired gauges as well as with newly developed wirelessly connected strain-measuring system. Both measurements were carefully compared and the accuracy of the developed system was demonstrated. Results were also compared with numerical simulations deployed with FE models and on such a basis; the reliability of the developed wireless system was proven. Finally, suggestions of potential research trends in this area are provided
Abstract
n this paper, an experimental test performed on a hybrid steel plate girder was subjected to concentrated loads at the end of an unstiffened panel is presented. This load [...]
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A monolithic FE formulation for the analysis of membranes in fluids
R. Rossi, P. Ryzhakov, E. Oñate

International Journal of Space Structures (2009). Vol. 24 (4), pp. 205-210

Abstract
We propose here an efficient approach for treating the interaction between membranes and fluids. Slight compressibility of the fluid is assumed. Classical total Lagrangian formulation including wrinkling is adopted for the membrane representation, whereas fluid is treated in an updated Lagrangian manner, developed in the current work. Assumption of slight compressibility of the fluid enables one to define the monolithic fluid-membrane system in a natural way. The displacements are the primary variables of both the fluid and the membrane domains. The formulation adopts the Particle Finite Element Method (PFEM) philosophy for free-surface identification and mesh regeneration. Three examples illustrate the functionality of the formulation in application to FSI problems involving motion of membranes in water
Abstract
We propose here an efficient approach for treating the interaction between membranes and fluids. Slight compressibility of the fluid is assumed. Classical total Lagrangian [...]
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Nonlinear Formulations of a Four-Node Quasi-Conforming Shell Element
G. Lomboy, S. Suthasupradit, K. Kim, E. Oñate

Archives of Comp. Meths. Engng. (2009). Vol. 16 (2), pp. 189-250

Abstract
The quasi-conforming technique was introduced in the 1980’s to meet the challenge of inter-elements conforming problems and give a unified treatment of both conforming and nonconforming elements. While the linear formulation is well established, the nonlinear formulation based on the quasi-conforming technique that includes geometric and material nonlinearity is presented in this paper. The formulation is derived in the framework of an updated Lagrangian stress resultant, co-rotational approach. The geometric nonlinear formulation provides solutions to buckling and postbuckling behaviour while the material nonlinear formulation considers the spread of plasticity within the element while maintaining an explicit construction of element matrices. Aside from the elasto-plastic constitutive relation, formulations on laminate composites and reinforced concrete are also presented. The formulations of laminate composite and reinforced concrete material are present based on the layer concept, the material properties can vary throughout the thickness and across the surface of a shell element. The various failure criteria for laminate composite are included in the formulation which makes it possible to analyses the progressive failure of fibre and matrix. For the reinforced concrete material, the nonlinearities as a result of tensile cracking, tension stiffening between cracks, the nonlinear response of concrete in compression, and the yielding of the reinforcement are considered. The steel reinforcement is modeled as a bilinear material with strain hardening.
Abstract
The quasi-conforming technique was introduced in the 1980’s to meet the challenge of inter-elements conforming problems and give a unified treatment of both conforming [...]
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Advances in discrete element modelling of underground excavations
C. Labra, J. Rojek, E. Oñate, F. Zárate

Acta Geotechnica (2009). Vol. 3 (4), pp. 317-322

Abstract
The paper presents advances in the discrete element modelling of underground excavation processes extending modelling possibilities as well as increasing computational efficiency. Efficient numerical models have been obtained using techniques of parallel computing and coupling the discrete element method with finite element method. The discrete element algorithm has been applied to simulation of different excavation processes, using different tools, TBMs and roadheaders. Numerical examples of tunnelling process are included in the paper, showing results in the form of rock failure, damage in the material, cutting forces and tool wear. Efficiency of the code for solving large scale geomechanical problems is also shown
Abstract
The paper presents advances in the discrete element modelling of underground excavation processes extending modelling possibilities as well as increasing computational efficiency. [...]
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Personal information “management” (PIM), not just personal information “retrieval”
D. Barreu

El profesional de la información (2009). Vol. 18, (4), 90

Abstract
Comparison of the characteristics and behaviour of people who are sorting and archiving physical and digital objects. There is limited selection –and also little interest– in tools for classifying digital objects that subsequently allow easy interaction with them or mental reflection while reviewing them. Thanks to the availability of inexpensive computer memory, people tend to save everything without categorizing, and trust –erroneously– only in good retrieval skills. Much more research in personal information management systems (PIM) is needed.
Abstract
Comparison of the characteristics and behaviour of people who are sorting and archiving physical and digital objects. There is limited selection –and also little interest– [...]
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Wikipedia as controlled vocabulary: has the traditional authority control been surpassed?
J. Jiménez-Pelayo

El profesional de la información (2009). Vol. 18, (4), 89

Abstract
Wikipedia, the free encyclopaedia, is the first project to have been born specifically from and for the web and which has developed an authority control system for access to their information. Here, the different elements, procedures and principles which make up the Wikipedia authority control system is analysed, and a critical analogy is traced between them and those that meet the traditional authority control applied to bibliographical catalogues. From the critical comparison of both models, one wonders up to what point the authority control, constrained by the weight of tradition and by its hopeless adaptation to technology, has been surpassed by developments such as Wikipedia which are based on a philosophy of flexibility and common sense and where the rules are decided by and for the user. The enormous potential and reach of the Wikipedia authority model make it a true contender to become the normal system of access to the Semantic Web
Abstract
Wikipedia, the free encyclopaedia, is the first project to have been born specifically from and for the web and which has developed an authority control system for access [...]
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Bibliometric assessment of universities with Scival of Elsevier
D. Torres-Salinas

El profesional de la información (2009). Vol. 18, (4), 88

Abstract
Research, its management and its policies represent a major effort for Spanish universities but few of these institutions have a scientific information system with bibliometric indicators for decision making. Aware of this gap, Elsevier has launched Scival. It is a web platform intended to assess institutions through maps and indicators calculated from the Scopus database. In this article we review this new product. We first describe the scientific basis of the platform that is based on the works of Klavan and Bojack about co-citation maps of science and the identification of paradigms. Secondly we describe its interface and its utilities, paying particular attention to the so-called Wheel of science. Finally, we discuss some critical aspects of Scival
Abstract
Research, its management and its policies represent a major effort for Spanish universities but few of these institutions have a scientific information system with bibliometric [...]
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Evaluation of national libraries: creation of an international standard and its application to the National Library of Spain
M. De-la-Mano, B. Albelda-Esteban

El profesional de la información (2009). Vol. 18, (4), 87

Abstract
National libraries have recently adopted a quality assessment culture using performance indicators. The project for devising Technical Report ISO/TR 28118 regarding performance indicators for national libraries is explained from its beginnings. This is a specific common standard that permit benchmarking among similar institutions at the international level. The involvement of the international bodies IFLA, ISO and CENL in this initiative is described based on observation of the situations common to all national libraries. The technical process of drawing up the report is likewise described, along with its structure and contents. Also dealt with is the recent experience of the National Library of Spain in incorporating performance indicators to its evaluation processes and applying the ISO report indicators.
Abstract
National libraries have recently adopted a quality assessment culture using performance indicators. The project for devising Technical Report ISO/TR 28118 regarding performance [...]
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Integrating digital reference services into library management: experiences based on Koha
N. Lloret-Romero, A. Sellés-Carot, M. Mañas-Carbonell, F. Canet-Centellas

El profesional de la información (2009). Vol. 18, (4), 86

Abstract
The digital environment and information and communication technologies open up new ways of providing library services, including the reference service, the principal aim of which is to address users’ queries and information needs. Putting the reference service in place in this new environment requires redesigning the policies, procedures and resources applied to it and therefore an analysis of the services and functions of the computing tools available must be undertaken. Integrated library management systems which involve multiple functionalities for delivering services, or which expand the capacity for their delivery, must also respond to the requirements for putting this type of service in place. This article sets out the results obtained in a study carried out on several examples of integrating new reference services into a library management system (Koha), which not only enables these services to be delivered but also expands the options for using the data for their improvement and development.
Abstract
The digital environment and information and communication technologies open up new ways of providing library services, including the reference service, the principal aim [...]
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InfoSud Digital: a virtual reference service for cooperative development
F. Ginés-Huertas

El profesional de la información (2009). Vol. 18, (4), 85

Abstract
InfoSud Digital promotes social awareness of international development collaborations. A VRS (Virtual Reference Service) using the Question Point tool from OCLC was created for this purpose. The ultimate goal is to create a network of information and documentation on cooperation for development. InfoSud Digital is a project developed by InfoSud, the information centre of the Patronat Sud-Nord of the University of Valencia.
Abstract
InfoSud Digital promotes social awareness of international development collaborations. A VRS (Virtual Reference Service) using the Question Point tool from OCLC was created [...]
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Pregunte: las bibliotecas responden (Ask a librarian). Virtual reference services in Spain’s public libraries
M. Cuadrado-Fernández, E. Rivera-Díaz

El profesional de la información (2009). Vol. 18, (4), 84

Abstract
Review and development of the Spanish virtual reference service Pregunte: las bibliotecas responden (Ask a librarian). Description of main characteristics, workflows and statistical analysis. Description of the recently established chat service
Abstract
Review and development of the Spanish virtual reference service Pregunte: las bibliotecas responden (Ask a librarian). Description of main characteristics, workflows and statistical [...]
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Virtual reference in Seville University Library: a shared experience
N. González-Fernández-Villavicencio, J. Barrera-Gómez, M. Gómez-Fernández, M. Moscoso-Castillo, V. Santos-Flores, M. Suárez-Samaniego

El profesional de la información (2009). Vol. 18, (4), 83

Abstract
Reference services in academic libraries are far from dead and technologies of the social web are facilitating and encouraging an ever increasing demand for virtual reference with applications available to everyone. The open source software LibraryH3lp has enabled the Library of the University of Seville to establish a virtual reference service shared among 19 libraries to answer common and specialized questions and explain the use of the Fama library catalog. We present a first assessment of the service that will go live in the academic year 2009-2010.
Abstract
Reference services in academic libraries are far from dead and technologies of the social web are facilitating and encouraging an ever increasing demand for virtual reference [...]
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The use of robots.txt and sitemaps in the Spanish public administration
B. Martín-Galán, T. Hernández-Pérez, D. Rodríguez-Mateos, D. Peña-Gil

El profesional de la información (2009). Vol. 18, (4), 82

Abstract
Robots.txt and sitemaps files are the main methods to regulate search engine crawler access to its content. This article explain the importance of such files and analyze robots.txt and sitemaps from more than 4,000 web sites belonging to spanish public administration to determine the use of these files as a medium of optimization for crawlers.
Abstract
Robots.txt and sitemaps files are the main methods to regulate search engine crawler access to its content. This article explain the importance of such files and analyze robots.txt [...]
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Research and development in digital preservation: an international review
M. Térmens

El profesional de la información (2009). Vol. 18, (4), 81

Abstract
The article presents a survey of international research studies and development in digital preservation, devoting a section to the situation in Spain. The author outlines applications in areas such as institutional repositories, administrative records, personal archives, aerospace industry and museum archives, but the greatest attention is given to digital preservation applications in libraries and archives. The pre-eminent role of certain libraries and the national archives and records of certain countries is evident in an analysis of the protagonists of this research, as well as the emerging role of software companies. The major lines of research include the integration of tools to create integrated preservation systems.
Abstract
The article presents a survey of international research studies and development in digital preservation, devoting a section to the situation in Spain. The author outlines [...]
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Personal information management using concept mapping software
J. Tramullas, A. Sánchez-Casabón, P. Garrido-Picazo

El profesional de la información (2009). Vol. 18, (4), 80

Abstract
Personal information management (PIM) raises some problems because the software tools that are used don’t adequately respond to user behaviour and activities. The concept and personal information management problems are reviewed, along with the software tools used for this task. A qualitative assessment explores whether an approach based on software tools for conceptual maps can address the problems discussed.
Abstract
Personal information management (PIM) raises some problems because the software tools that are used don’t adequately respond to user behaviour and activities. The concept [...]
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Digital reference: concept, technologies, and implementation in information centres
J. Merlo-Vega

El profesional de la información (2009). Vol. 18, (4), 79

Abstract
Digital reference is the service offered by libraries and information centres so that users can ask questions through the Internet. The concept of digital reference is described, along with the different typologies based on various criteria. The technologies used today for receiving questions and sending answers are presented. Guidelines are suggested for implementing a digital reference service, based on four criteria: the actors involved, the techniques used, the available resources and the management of the service. It concludes by highlighting the value of digital reference as an online service that expands the range of patrons.
Abstract
Digital reference is the service offered by libraries and information centres so that users can ask questions through the Internet. The concept of digital reference is described, [...]
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Reference services for a digital society
J. Merlo-Vega

El profesional de la información (2009). Vol. 18, (4), 78

Abstract
Reference services have developed at the same pace as technology. Different aspects of the information society related to reference services provided by libraries and information centres are presented, including a description of the ubiquity, immediacy and participation that define the digital society. Digital reference is part of the information society and reflects the evolution of reference services offered by information centres. The characteristics of digital reference are described: telematic services, hybrid collections and skilled professionals.
Abstract
Reference services have developed at the same pace as technology. Different aspects of the information society related to reference services provided by libraries and information [...]
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Prácticas de las bibliotecas universitarias argentinas (Mercedes Patalano)
L. Ramos-Simón

El profesional de la información (2009). Vol. 18, (4), 77

Abstract
Patalano, Mercedes (2008). Prácticas de las bibliotecas universitarias argentinas. Reflexiones críticas en el contexto de la comunicación académica y sus representaciones en la Web. Editorial Teseo, Buenos Aires, 160 pp. ISBN: 978 9871354191
Abstract
Patalano, Mercedes (2008). Prácticas de las bibliotecas universitarias argentinas. Reflexiones críticas en el contexto de la comunicación académica y sus representaciones [...]
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Manual de indización: teoría y práctica (Isidoro Gil-Leiva)
A. Alonso-Arroyo

El profesional de la información (2009). Vol. 18, (4), 76

Abstract
Gil-Leiva, Isidoro (2008). Manual de indización: teoría y práctica. Gijón: Trea, 432 p. (Biblioteca y administración cultural; 193). ISBN: 978 84 9704 367 0
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OSTI-DOE, the source of energy information. Interview with Karen Spence
F. Peset, T. Baiget

El profesional de la información (2009). Vol. 18, (4), 75

Abstract
An interview with Karen Spence, assistant director of Information Systems, Office of Scientific and Technical Information (OSTI), United States Department of Energy, describes the major OSTI databases, repositories and scientific and technical information co-operation projects (especially on energy and environment).
Abstract
An interview with Karen Spence, assistant director of Information Systems, Office of Scientific and Technical Information (OSTI), United States Department of Energy, describes [...]
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Aggregation of bibliometric indices to evaluate the scientific production of researchers
F. Herrera, E. Herrera-Viedma, S. Alonso, F. Cabrerizo

El profesional de la información (2009). Vol. 18, (4), 74

Abstract
In this paper we show that the aggregation of bibliometric indices is an appropriate way to evaluate scientific production of researchers because it allows us to develop much more precise new bibliometric indices that combine the advantages of each index that is aggregated.
Abstract
In this paper we show that the aggregation of bibliometric indices is an appropriate way to evaluate scientific production of researchers because it allows us to develop much [...]
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Evolution of social network services
M. Ros-Martín

El profesional de la información (2009). Vol. 18, (4), 73

Abstract
The paper exposes a brief history of social network services on the Web that have evolved under the concept of Web 2.0, along with the most significant examples of these platforms. The concept of social networking and the main tests used to study them are explained, as well as their implications within different kinds of social capital (weak and strong ties) and the impact that the different web services can have on the relationship among their users.
Abstract
The paper exposes a brief history of social network services on the Web that have evolved under the concept of Web 2.0, along with the most significant examples of these platforms. [...]
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The VideoActive project: Television as public service and audiovisual patrimony
D. Fernández-Quijada, M. Fortino

El profesional de la información (2009). Vol. 18, (4), 72

Abstract
The need to preserve audiovisual archives and the possibilities for their dissemination resulting from digitisation have generated a growing interest in the development of platforms to provide access to their content. One of these platforms is VideoActive, a pan-European collaborative project that has developed a thematic approach to European history through TV and to the history of European TV. One of its key objectives is to encourage collaboration with the academic world. The consortium has developed its own technical infrastructure to offer at least 10,000 items from 10 different European archives, including that of Televisió de Catalunya, the Catalan public service broadcaster that seeks to contribute to international awareness of Catalan culture.
Abstract
The need to preserve audiovisual archives and the possibilities for their dissemination resulting from digitisation have generated a growing interest in the development of [...]
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Meridià: a web portal to disseminate science from a comprehensive and cooperative view
L. Arguimbau, A. Cervera, R. Latorre, M. Martí

El profesional de la información (2009). Vol. 18, (4), 71

Abstract
The proper functioning of the Research, Development and Innovation (R&D&I) cycle requires an efficient processing of scientific information. The Institute for Catalan Studies (IEC) possesses a scientific observatory which recently presented the web portal Meridià. From a global point of view, this project aims to be a cooperative initiative to integrate and share information with other agents of the scientific system, providing a thorough understanding of their environment and the evolution of the different areas in science and technology.
Abstract
The proper functioning of the Research, Development and Innovation (R&D&I) cycle requires an efficient processing of scientific information. The Institute for Catalan Studies [...]
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Strategies to improve the dissemination of research results with the Web 2.0
D. Torres-Salinas, E. Delgado-López-Cózar

El profesional de la información (2009). Vol. 18, (4), 70

Abstract
Scientific communication is being enriched by the introduction of new ways of storage, publication and dissemination of the results. These include the services of the Web 2.0 which are still largely unknown to researchers. In this context the objective of this paper is to illustrate how we can strategically use Web Services 2.0 to disseminate and give greater visibility to scientific publications. To this end we present a series of services of interest to scientific communication (Blogger, Twitter, Facebook, Slideshare y E-Lis) and explain the role they can play in communicating scientific results. It also shows how these services should be logically interrelated, which we call the strategic dissemination cycle. In the last section, the authors collected a set of webmetric indicators classified into three groups (social influence, use, recognition) to evaluate the success of the dissemination strategy and the visibility of a work in the Web 2.0.
Abstract
Scientific communication is being enriched by the introduction of new ways of storage, publication and dissemination of the results. These include the services of the Web [...]
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Retrieval of very large numbers of items in the Web of Science: an exercise to develop accurate search strategies
R. Arencibia-Jorge, L. Leydesdorff, Z. Chinchilla-Rodríguez, R. Rousseau, S. Paris

El profesional de la información (2009). Vol. 18, (4), 69

Abstract
The Web of Science interface counts at most 100,000 retrieved items from a single query. If the query results in a dataset containing more than 100,000 items the number of retrieved items is indicated as >100,000. The problem studied here is how to find the exact number of items in a query that leads to more than 100,000 items. One way to achieve this objective is presented. The retrieval of the entire scientific production from the United States in a specific year (2007) is counted and an advanced search strategy is designed. Different sections of items can be retrieved using the Source field of the database. A Boolean statement was created with the aim of eliminating overlapped sections and improving the accuracy of this search strategy.
Abstract
The Web of Science interface counts at most 100,000 retrieved items from a single query. If the query results in a dataset containing more than 100,000 items the number of [...]
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ISOC database as information system: a major source for the analysis of Human and Social Sciences in Spain
T. Abejón-Peña, Á. Maldonado-Martínez, L. Rodríguez-Yunta, M. Rubio-Liniers

El profesional de la información (2009). Vol. 18, (4), 68

Abstract
The ISOC database is presented as an information system that is very useful for the dissemination and the study of scientific production in human and social sciences in Spain since 1975. First of all, an historical overview is proposed. Secondly, quality elements that distinguish ISOC from other documentary systems are described. Thirdly, its suitability for bibliometric studies on the scientific production of these subjects published in Spain is discussed. Finally, some data about its use by the scientific and scholarly community are presented.
Abstract
The ISOC database is presented as an information system that is very useful for the dissemination and the study of scientific production in human and social sciences in Spain [...]
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Use of patent databases as a tool for technology watch
A. Hidalgo-Nuchera, S. Iglesias-Pradas, Á. Hernández-García

El profesional de la información (2009). Vol. 18, (4), 67

Abstract
Given the importance of innovation and technology development in a country’s economy, there has been an increasing need for selecting indicators to measure the degree of innovation of its companies. The indicators related to patents offer an excellent measure of this capability and can be used as an important source of information by innovative organizations, although the studies assessing this utility are scarce. This study, conducted throughout 2007, proposes a technology watch oriented analysis of the level of use of patent databases from more than 500 Spanish companies that have issued at least one patent in the period 1988-1998, followed by discussion of the study results. The analysis took into account global data, company size and sector of activity
Abstract
Given the importance of innovation and technology development in a country’s economy, there has been an increasing need for selecting indicators to measure the degree of [...]
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Google Scholar as a tool for research assessment
D. Torres-Salinas, R. Ruiz-Pérez, E. Delgado-López-Cózar

El profesional de la información (2009). Vol. 18, (4), 66

Abstract
Google Scholar is a search engine that specializes in scientific information and in the identification of the citations that academic papers receive, making it a strong competitor for other citations indexes. For this reason, several studies have attempted to evaluate its capacity as a bibliometric tool. Due to this interest, we present an introduction to its use and the advantages and disadvantages versus Scopus and Web of Science. First, its way of collecting information and features of its interface are analyzed. The following section describes the results that Google Scholar generates. Thirdly, we analyze the coverage of information sources and the different document types to be found, showing how this coverage universe offers different citations versus other products. Finally, we specify the standardization problems of Google Scholar and offer a number of precautions that must be taken into account when using Google Scholar as an evaluation tool.
Abstract
Google Scholar is a search engine that specializes in scientific information and in the identification of the citations that academic papers receive, making it a strong competitor [...]
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Spanish public universities in Google Scholar: presence, evolution and coverage of their scientific output
E. Orduña-Malea, J. Serrano-Cobos, N. Lloret-Romero

El profesional de la información (2009). Vol. 18, (4), 65

Abstract
The validity of Google Scholar as a service that reflects properly the scientific output of a university is analyzed, comparing its coverage of Spanish public universities with that of Scopus. The presence and evolution of scientific documentation on the websites of the Spanish public universities from January to July (both months inclusive) 2009 is also studied. The results show that, despite finding some interrelationship between Scholar and Scopus concerning the productivity of institutions, there are large differences in the total results that override the latter as a valid reflection of university productivity. Finally, Scholar shows positive, albeit modest, growth during the studied period for most university websites analyzed
Abstract
The validity of Google Scholar as a service that reflects properly the scientific output of a university is analyzed, comparing its coverage of Spanish public universities [...]
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