Abstract

The call for papers resulted in a high number of submis- sions, from which we have been able to select 12 excellent papers dealing with the different aspects of satellite commu- nications and navigation. Multiple-input multiple-output (MIMO) techniques are attracting a considerable amount of attention from within the terrestrial wireless community. The first paper of this spe- cial issue, “Multisatellite MIMO communications at Ku band and above: investigations on spatial multiplexing for capac- ity improvement and selection diversity for interference mit- igation,” considers the application of such technology over a satellite platform operating in the Ku band and above. The paper considers how MIMO can be used to increase capac- ity by using a satellite spatial multiplexing system and how antenna selection can be used to mitigate interference. The next paper “Investigations in satellite MIMO channel model- ing: accent on polarization” looks at MIMO systems from the polarization diversity point of view and dwells on the satellite cooperative communication concepts. Switch and stay combining (SSC) is a form of diversity technique used in digital receivers to compensate for fade events introduced by the mobile channel. The third paper “Performance analysis of SSC diversity receivers over corre- lated Ricean fading satellite channels” investigates the per- formance of dual-branch SSC receivers for different fading channel characteristics. The next four papers deal with the emerging scenario of mobile digital video broadcasting (DVB-S2 and RCS mo- bile). Alternative approaches to counteracting fading chan- nels introduced when operating in a train environment re- ceiving satellite DVB-S2 are presented in the paper “Ad- vanced fade countermeasures for DVB-S2 systems in railway scenarios.” Here, as a result of simulation analysis, antenna diversity and packet-level forward error correction mecha- nisms are proposed and their impact is evaluated with respect to the receiver design and system complexity. The theme of DVB-S2 is continued with the paper “Capacity versus bit er- ror rate trade-off in the DVB-S2 forward link,” which inves- tigates how satellite capacity can be optimised for DVB-S2 transmissions. The DVB return channel via satellite (DVB- RCS) is then addressed in “Frequency estimation in iterative interference cancellation applied to multibeam satellite sys- tems,” which considers the application of interference cancel- lation on the reverse link of a multibeam satellite system, us- ing DVB-RCS with convolutional coding as an example. The paper “A QoS architecture for DVB-RCS next-generation satellite networks” proceeds to design and emulate a quality- of-service (QoS) architecture that demonstrates using real multimedia applications how QoS can be supported over a DVB-RCS network. 2 EURASIP Journal on Wireless Communications and Networking Synchronization aspects are dealt with in “Maximum likelihood timing and carrier synchronization in burst-mode satellite transmissions.” The paper addresses the problem of achieving synchronisation for a burst-mode satellite trans- mission over an AWGN channel. The subject of burst trans- mission continues with the paper “Burst format design for optimum joint estimation of Doppler-shift and Doppler- rate in packet satellite communications,” which considers optimising the burst-format of packet-oriented transmis- sions by proposing very-low-complexity algorithms for car- rier Doppler-shift and Doppler-rate estimation. A network comprising satellite and high-altitude plat- forms is considered in the paper “TCP-call admission con- trol interaction in multiplatform space architectures.” Cross- layer techniques are implemented by means of TCP feeding back into call admission control (CAC) procedures for the purpose of prevention of congestion and improvement in QoS. Finally, since navigation is an extremely important part of the satellite system family, we have included two papers. The first paper “Efficient delay tracking methods with side- lobes cancellation for BOC-modulated signals” deals with bi- nary offset carrier (BOC) modulation, which is adopted in typical navigation systems. The paper considers how to improve the tracking of the main lobe of the BOC-modulated signal by using sidelobe suppression techniques. An alternative approach based on filter bank processing is presented in “Analysis of filter-bank-based methods for fast serial acqui- sition of BOC-modulated signals” to conclude the special issue. Document type: Part of book or chapter of book

Abstract

Civil aviation air traffic undergoes many random disturbances. Air traffic controllers watch the real traffic and ensure that it is free from collision hazards in the whole airspace — the ATC sector — under their control. The ATFM service takes care that the flow capacity in each sector, called capacity of the air traffic sector, is not exceeded. In the paper an original method of model estimation of the capacity of the designed ATC sectors is described. In this method an experimentally established statistical relationship between the random variables of control load and the air traffic density is used. The capacity of a sector was found from the joint probability distribution of such a two-dimensional random variable model determined as a quanti le of adequate order. This method was verified in practice by determining the capacity of the designed new ATC sectors in FIR Warsaw. Document type: Book

Abstract

This chapter discusses man-machine interface. PLC has to “connect” to human operators, accepting commands from them and displaying the status of the plant in a form that can readily and easily be understood. A digital display driven in BCD normally uses one of the unused binary codes, 1010 to 1111, to generate a blank display. Simple digital inputs (pushbuttons, joysticks, switches) are normally allocated one input per motion and do not require anything particularly special. Concerning PLC with analog signals, flows, temperatures, pressures, etc., these will usually be displayed to the operator. A graphics terminal has just two connections to the outside world, a serial link connection and a power supply. The Allen Bradley Panelview family was designed to replace switches, pushbuttons, numeric displays, and similar devices. The Panelview built up a graphics screen with semigraphic characters placed on a screen with a “pick and place” menu approach. Siemens provides a vast range of operator terminals from simple text-only message displays to complete computer-based Scada systems. One major advantage of graphical displays is that mistakes can be rectified without leaving scars, albeit at some cost. The operator will need to input data and initiate actions. Where a simple text message is to be displayed, possibly with embedded data, message displays driven by a simple serial link carrying ASCII coded characters can be used. PCs have much better graphics capability than the average PLC, so it is not surprising that PCs are increasingly being used as the link between humans and PLC systems. Document type: Part of book or chapter of book

Abstract

The paper reports the development and application of a SPH (smoothed particle hydrodynamics) based simulation of rapid filling of pipelines, for which the rigid-column model is commonly used. In this paper the water-hammer equations with a moving boundary are used to model the pipe filling process, and a mesh-less Lagrangian particle approach is employed to solve the governing equations. To assign boundary conditions with time-dependent (upstream) and constant (downstream) pressure, the SPH pressure boundary concept proposed recently in literature is used and extended. Except for imposing boundary conditions, this concept also ensures completeness of the kernels associated with particles close to the boundaries. As a consequence, the boundary deficiency problem encountered in conventional SPH is remedied. The employed particle method with the SPH pressure boundary concept aims to predict the transients occurring during rapid pipe filling. It is validated against laboratory tests, rigid-column solutions and numerical results from literature. Results obtained with the present approach show better agreement with the test data than those from rigid-column theory and the elastic model solved by the box scheme. It is concluded that SPH is a promising tool for the simulation of rapid filling of pipelines with undulating elevation profiles. Keywords: Rapid filling of pipelines; Undulating elevation profile; SPH

Abstract

Study of interactions between two consecutive layers of ATM under increased traffic.Results highlight an exponential growth in delay costs if constant network capacity.Results highlight an unmanageable controller workload if network capacity is high.We find a compromise by controlling delay costs growth with a sector capacity growth.We quantify research objectives for future work on air traffic control optimization. Air traffic in Europe is predicted to increase considerably over the next decades. In this context, we present a study of the interactions between the costs due to ground-holding regulations and the costs due to en-route air traffic control. We dulator that considers the regulation delays, aircraft trajectories, and air conflict resolution. Through intensive simulations based on traffic forecasts extrapolated from French traffic data for 2012, we compute the regulation delays and avoidance maneuvers according to two scenarios: the current regulations and no regulations. The resulting cost analysis highlights the exponential growth in regulation costs that can be expected if the procedures and the airspace capacity do not change. Compared to the delay costs, the costs of the air traffic control are negligible with or without regulation. The analysis reveals the heavy controller workloads when there are no regulations, suggesting the need for regulations that are appropriate for large traffic volumes and an improved ATC system. These observations motivate the design of a third scenario that computes the sector capacities to find a compromise between the increase in the delay costs due to ground-holding regulations and the increase in the controller workload. The results reveal the sensitivity of the delay costs to the sector capacity; this information will be useful for further research into ATM sector capacity and ATC automated tool design. Finally, because of the growing interest in the free flight paradigm, we also perform a traffic and cost analysis for aircraft following direct routes. The results obtained highlight the fuel and time savings and the spatial restrictions that companies use to avoid congested areas. Document type: Article

Abstract

More and more interfaces are designed for ‘everybody’, instead of with a specific user-group in mind. In practice, most of them are still used by the ‘typical Internet-user’, the highly educated, white young male with extensive computer and Internet-experience. Amsterdam-based digital city DDS is no exception to this rule. In this article, the interface of DDS is studied with the help of ten first-time users with a more diverse background. Did they face any barriers in using DDS? And what kind of work did they need to perform to use the interface? This study shows that the most serious problems the first-time users faced were not caused by a lack of skill, but by the different technological frame they had. Thus, a script-analysis with the help of ‘outsiders’ seems to be an effective way to uncover some exclusion-processes of a digital city.

Abstract

Designed a DNA-based genetic algorithm under the universal architecture of organic computing, combined particle swarm optimization algorithm, introduced a crossover operation for the particle location, can interfere with the particles speed, make inert particles escape the local optimum points, enhanced PSO algorithm's ability to get rid of local extreme point. Utilized improved algorithms to train the RBF neural network models, predict short-time traffic flow of a region intelligent traffic control. Simulation and error analysis of experimental results showed that, the designed algorithms can accurately forecast short-time traffic flow of the regional intelligent transportation control, forecasting effects is better, can be effectively applied to actual traffic engineering.

Abstract

This paper presents a new approach for automated merging multiple aircraft flows in a busy Terminal Maneuvering Area (TMA). This work is motivated by the current overloaded airspace in the Beijing Capital international airport, the highlighted delay in the China air transportation and the need of more efficient methods to help air traffic controllers. Present research consists of a new approach to optimize a set of aircraft planned to land at a given airport based on multi-agents technique, which is automated generating comprehensive sequencing plan and conflicts-free trajectories.The architecture of the system is based on a Point Merge (PM) route structure to enable expediting or delaying aircraft while staying on lateral navigation mode.The whole system is designed by two main models to manage the process of arriving flows: Sequencing leg and Link. And then, 4 kinds of agents are designed to support the implementation of this automated system: aircraft agent, flow manager agent, conflict detection and resolution agent and 4D trajectory planning agent. We consider the 4D trajectory-based operation situation in TMA and apply different wake turbulence constraint in these two models. Finally, aconclusion is made and future work is outlined. Refereed/Peer-reviewed

Abstract

Hot-potato routing is commonly used to break tie among multiple equally-good exit points associating with inter-domain BGP routes. However, hot-potato routing only takes the network control plane into consideration, where it provides the routers the possibility of enabling early exit of traffic using barely protocol-related information of IGP distance. In this paper, we argue that egress selection of inter-domain routing should pay more attention to traffic forwarding, because the large traffic migration caused by egress change, although not quite often, can degrade the network performance or even make the network crash. We propose Egress Selection based on Traffic Migration Prediction (ES-TMP). We use traffic demand to predict the traffic migration, which is used as important criteria for egress selection. If the volume of traffic migration is large, ES-TMP keeps the egress unchanged. Otherwise, the small traffic migration enables the routers use the closest egress without apparent influence on network performance. ES-TMP can either be implemented with standard BGP protocol or by dedicated servers to perform global routing optimization.

Abstract

Under an increasing maritime transport in the Baltic Sea, and especially in the Gulf of Finland, the possibility of environmental harm and accidents due to shipping pressure is growing. To counteract increasing risks, adequate measures for accident prevention and mitigation of environmental consequences are critically important. The Gulf of Finland Mandatory Ship Reporting System (GOFREP) is a the complex socio-technical maritime transport safety management system that has been in efficient operation since 2004 and it is open to further improvement and development. However, environmental safety is not explicitly covered by the GOFREP so far. According to our working hypothesis, the Systems Theoretic Accident Models and Processes (STAMP) can be extended beyond the area of socio-technical system safety into realm of complex eco-socio-technical systems safety. This paper attempts to demonstrate the conceptual potential of STAMP based on adaptive management of the Maritime Spatial Planning processes and integrated safety management of eco-socio-technical maritime transport system.