Abstract

 

The computer simulation of forced vibrations induced on a water pool is presented in this paper. The complexity of the seismic fluid-structure interaction problem is accentuated by the large free surface motion. To overcome this difficulty, the arbitrary Lagrangian Eulerian (ALE) finite element formulation is employed. Moreover, the nonlinear behavior of the free surface motion is also taken into account. The results of the numerical simulation are compared with published experimental data and the effectiveness of the ALE algorithm is demonstrated

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

This project studies the aggravating problem of road traffic and congestion, and some of its solutions: autonomous cars and traffic simulation software. Unreal Engine is presented as a new option for simulating a traffic environment. An application is programmed that allows the user to create and edit roadtracks by clicking and dragging in the editor, along with autonomous vehicle models to populate them with. The simulator is tested using different scenarios and obtaining relevant data. Finally, the obtained conclusions are mentioned, along with ideas and guidelines for future developmen

Abstract

The main objective of this project is to design an automation control system for a new arrival procedure at Palma de Mallorca airport, which is the Point Merge System (PMS). This new system, suggested by Cercle d’Economia de Mallorca, allows performing Continuous Descent Approach (CDA), reducing fuel consumption, CO2 and acoustic emissions, while safety levels are enhanced and arrival capacity is increased. Additionally, the fact of introducing the automation control would remove the air traffic controllers presence, only needing one person to monitor the system. The PMS concept was developed by Eurocontrol and is based on the merging of two arrival flows in one single entry point, which is afterwards linked to the airport runway. Nowadays, these flows are managed by controllers who give the “direct-to” instruction to pilots to fly towards the merge point, whereas in this project this will be done by the system. In order to achieve the aim of the project, the Network Strategic Tool (NEST) from Eurocontrol has been used, which allows traffic simulations, together with Matlab, in which the NEST files have been read and different time computations have been performed to determine when the aircraft gets the “direct-to” and in this way ensure safety. The obtained results are for two diferent scenarios. On one hand, real traffic data from summer 2018 has been considered, which are used to know the current behavior of the system. On the other hand, with the webpage Demand Data Repository (DDR) of Eurocontrol a traffic forecast for summer 2024 has been generated, which is used to estimate the behaviour and capacity of the system in a future with more traffic. With the results analysis, it is possible to check that nowadays most aircraft would be authorized with a direct entry to the merge point, without waiting. For the 2024 case, most aircraft would have to stay inside the system with a waiting time due to the increase of flights. Lastly, in both scenarios route length increases, while it is possible to perform CDA thanks to the predictability obtained with the system. L’objectiu principal d’aquest projecte és dissenyar un sistema de control automàtic per un nou procediment d’arribades a l’aeroport de Palma de Mallorca, el Point Merge System (PMS). Aquest nou sistema, proposat pel Cercle d’Economia de Mallorca, permet realitzar Continuous Descent Approach (CDA), reduint el consum de fuel, les emissions de CO2 i l’impacte acústic, mentre que es milloren els nivells de seguretat i s’augmenta la capacitat de trànsit d’arribada. A més a més, el fet d’introduir el control automàtic eliminaria la presència dels controladors, necessitant únicament una persona que supervisés el sistema. El concepte de PMS va ser desenvolupat per Eurocontrol i es basa en la fusió de dos fluxos d’arribada en un únic punt d’entrada, que després s’enllaça amb la pista de l’aeroport. Actualment aquests fluxos són gestionats pels controladors que donen la instrucció “direct-to” als pilots perquè es puguin dirigir cap al punt final, mentre que en aquest projecte ho farà el propi sistema. Per aconseguir l’objectiu del projecte s’ha utilitzat el programa Network Strategic Tool (NEST) d’Eurocontrol, que permet fer simulacions de trànsit aeri, juntament amb Matlab, amb el qual s’han llegit els arxius del NEST i s’han realitzat diferents càlculs de temps per determinar quan l’avió obté el “direct-to” i així garantir la seguretat. Els resultats obtinguts són per dos escenaris diferents. Per una banda, s’han considerat dades de trànsit real de l’estiu de 2018, amb les quals sabem el comportament del sistema a dia d’avui. Per altra banda, a través de la pàgina web Demand Data Repository (DDR) d’Eurocontrol s’ha generat una previsió de trànsit per l’estiu de 2024, amb la qual s’estima el comportament i la capacitat del sistema en un futur amb més trànsit. Amb l’anàlisi dels resultats, es comprova que actualment la majoria d’avions serien autoritzats amb una entrada directa al punt final, sense necessitat d’esperar. En el cas de l’any 2024, la majoria d’avions hauria d’estar dins del sistema amb un temps d’espera degut a l’augment dels vols. Per últim, en els dos escenaris la distància recorreguda augmenta, mentre que es pot fer una aproximació CDA gràcies a la predictibilitat obtinguda amb el sistem

Abstract

English: road safety has become a main issue for governments and car manufacturers in the last twenty years. Thus, the concept of Intelligent Transportation Systems (ITS) appeared. This concept is used when talking about communication technologies between vehicles and infrastructure that improve transport safety, its management, environmental performance etc. Due to the high economic cost of real-life tests and experimentation, the use of simulators becomes really useful when developing ITS. Nonetheless, simulators not always include all the capabilities needed to simulate these kinds of networks. Thus, in this project the NCTUns simulator is modified in order to add new capabilities that allow users simulate ITS. Furthermore, urban and interurban scenarios are simulated in order to evaluate how the use of these networks decreases the drivers reaction time when an unexpected situation occurs and how modifications made in NCTUns work. Castellano: la seguridad en la carretera se ha convertido en un problema principal para gobiernos y fabricantes de automóviles en los últimos años. De esta forma, se creó el concepto de Sistema de Transporte Inteligente (STI), concepto utilizado al hablar sobre las tecnologías de comunicación entre vehículos e infraestructura que mejoran la seguridad vial en el transporte, su mejor gestión, su eficiencia medioambiental, etc. Debido al alto coste económico de probar STI en situaciones reales, el uso de simuladores es realmente útil a la hora de desarrollar STI. Así, en este proyecto el simulador NCTUns ha sido modificado con el objetivo de añadir nuevas posibilidades al simulador que ayuden a diseñar STI. Además, un escenario urbano y otro interurbano han sido simulados con el objetivo de evaluar como el uso de estas redes hace disminuir el tiempo de reacción del conductor cuando una situación inesperada ocurre y comprobar cómo funcionan los cambios realizados en el simulador. Català: la seguretat a la carretera ha esdevingut un problema principal pels governs i pels fabricants d'automòbils en els últims anys. D'aquesta manera, es crea el concepte de Sistema de Transport Intel'ligent (STI), concepte utilitzat en parlar sobre les tecnologies de comunicació entre vehicles i infraestructura que milloren la seguretat vial en el transport, la seva millor gestió, l'eficiència mediambiental, etc. A causa de l'alt cost econòmic de provar STI en situacions reals, l'ús de simuladors és realment útil a l'hora de desenvolupar STI. Així, en aquest projecte el simulador NCTUns ha estat modificat amb l'objectiu d'afegir noves possibilitats al simulador que ajudin a dissenyar STI a futurs usuaris. A més, un escenari urbà i un altre interurbà han estat simulats amb l'objectiu d'avaluar com l'ús d'aquestes xarxes fa disminuir el temps de reacció del conductor quan una situació inesperada succeeix i comprovar com funcionen els canvis realitzats en el simulador.

Abstract

We present an approach for validation of advanced driver assistance systems, based on randomized algorithms. The new method consists of an iterative randomized simulation using adaptive importance sampling. The randomized algorithm is more efficient than conventional simulation techniques. The importance sampling pdf is estimated by a kernel density estimate, based on the results from the previous iteration. The concept is illustrated with a simple adaptive cruise control problem.

Abstract

the level of traffic congestion rises and the complexity of traffic networks increases, the development of effective transportation strategies becomes the most challenging task for every transport authority. Meanwhile, advancements in computer technology and especially the technique of computer simulation offer a new effective way for testing plausible solutions prior to their implementation. Based on a microscopic traffic simulation model this paper presents an evaluation of the effectiveness of alternative traffic solution interventions on a main arterial in Nicosia, Cyprus. In particular, computer experiments are carried out to test various plausible scenario solutions. The scenarios under evaluation, involve the use of dedicated bus lanes, high occupancy vehicle lanes and road enhancement interventions. The simulation results show that an attractive scenario such as the use of dedicated bus lanes, if not designed properly, could bring disastrous results not only to the private car transport mode but also to the bus transport mode as coupling effects cause buses to get stuck with the rest of the traffic. By going through a computer experimentation process and scenario analysis a viable solution is derived, where restricted lanes for buses and high occupancy vehicles are introduced in combination with road geometry redesign and traffic re-direction at key points. 96 177 187 "p"Sponsors: WIT Transactions on The Built Environment Conference code: 71376

Abstract

present, gas pipeline networks in Europe are routinely monitored by vehicle and air patrols to protect them against damage by soil movement and third part interference. Because of the expenses, pipeline operators are investigating the possibilities to replace these traditional monitoring methods by remote sensing from space. A preliminary analysis shows that considerable savings can be achieved by deploying a user network of ground stations to receive the Synthetic Aperture Radar (SAR) data of the ENVISAT, RADARSAT-2. ALOS and TerraSAR satellite

Abstract

The number of private vehicles increased dramatically during the last two decades in the island of Cyprus. This phenomenon had a negative effect on the bus transport mode which over the years its use has been considerably reduced. As traffic congestion increased considerably during the same period the need for a high quality public transportation system became clear. This need is also supported by the demand for public transportation by the aging and disadvantaged population. The best way to attract people back to public transportation is to have a reliable bus system with a high quality of service which can compensate for the lack of freedom and exibility a private vehicle can provide. However such a system should not have a negative effect on the traffic network in terms of congestion and travel times but should coexist serving both the needs of people who do not drive and those who use the public transport mode. The purpose of this paper is to present the development and evaluation of a number of scenarios aiming at attracting commuters back to public transportation. This idea stems from the fact that surveys among the Cypriot commuters show that people will use buses if buses provide a fast and reliable service. For this purpose, microscopic simulation models are developed in order to examine several scenarios of dedicated bus lanes and bus priority schemes so that the buses can provide the desired level of service with the minimal impact on the rest of the traffic. © 2009 IFAC. 434 441 "p"Sponsors: IFAC Technical Committee on Transportation Systems TC 7.4 Conference code: 85831 Cited By :3

Abstract

Heterogeneous multicore systems have gained momentum, specially for embedded applications, thanks to the performance and energy consumption trade-offs provided by inorder and out-of-order cores. Micro-architectural simulation models the behavior of pipeline structures and caches with configurable parameters. This level of abstraction is well known for being flexible enough to quickly evaluate the performance of new hardware implementations, such as future heterogeneous multicore platforms. However, currently, there is no open-source micro-architectural simulator supporting both in-order and out-of-order ARM cores. This article describes the implementation and accuracy evaluation of a micro-architectural simulator of Cortex-A cores, supporting in-order and out-of-order pipelines and based on the open-source gem5 simulator. We explain how to simulate CortexA8 and Cortex-A9 cores in gem5, and compare the execution time of ten benchmarks with real hardware. Both models, with average absolute errors of only 7 %, are more accurate than similar microarchitectural simulators, which show average absolute errors greater than 15 %.