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Flexible triangular formation keeping of marine robotic vehicles using range measurements 1

IFAC Proceedings Volumes 2014年第3期47卷 5145-5150页

作者： Francisco Rego Jorge M. Soares António Pascoal A. Pedro Aguiar Colin Jones Laboratory of Robotics and Systems in Engineering and Science Instituto Superior Técnico University of Lisbon Lisbon Portugal Department of Electrical and Computer Engineering Faculty of Engineering University of Porto Porto Portugal Institute of Mechanical Engineering School of Engineering École Polytechnique Fédérale de Lausanne Lausanne Switzerland Distributed Intelligent Systems and Algorithms Laboratory School of Architecture Civil and Environmental Engineering École Polytechnique Fédérale de Lausanne Lausanne Switzerland National Institute of Oceanography Dona Paula Goa India

This paper addresses the problem of keeping an autonomous marine vehicle in a moving triangular formation by regulating its position with respect to two leader vehicles. The follower vehicle has no prior knowledge of the path described by the leaders but has access to their heading angle and is able to measure inter-vehicle ranges. It is assumed that the distance between the leaders is constant and known. A control strategy is adopted that generates speed and heading commands so as to drive suitably defined along track and cross track errors to zero. The commands are used as input to local inner loops for yaw and speed control. The paper describes the algorithms derived for range-based control and assesses their performance in simulations using realistic models of the vehicles involved. Tests with three autonomous marine vehicles equipped with acoustic modems and ranging devices allow for the evaluation of the performance of the algorithms in a real-world situation.

关键词： Autonomous Vehicles Marine systems Control Laws Formation Control Station Keeping Triangular Formations

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Opportunities and pitfalls of multi-core scaling using hardware transaction memory 13

Opportunities and pitfalls of multi-core scaling using hardw...

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4th Asia-Pacific Workshop on systems, APSys 2013

作者： Wang, Zhaoguo Qian, Hao Chen, Haibo Li, Jinyang School of Computer Science Fudan University China Institute of Parallel and Distributed Systems Shanghai Jiao Tong University China Department of Computer Science New York University United States

ISBN: (纸本)9781450323161

Hardware transactional memory, which holds the promise to simplify and scale up multicore synchronization, has recently become available in main stream processors in the form of Intel's restricted transactional memory (RTM). Will RTM be a panacea for multicore scaling? This paper tries to shed some light on this question by studying the performance scalability of a concurrent skip list using competing synchronization techniques, including fine-grained locking, lock-free and RTM (using both Intel's RTM emulator and a real RTM machine). Our experience suggests that RTM indeed simplifies the implementation, however, a lot of care must be taken to get good performance. Specifically, to avoid excessive aborts due to RTM capacity miss or conflicts, programmers should move memory allocation/deallocation out of RTM region, tuning fallback functions, and use compiler optimization. Copyright 2013 ACM.

关键词： Storage allocation (computer)

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Real-Time Environmental Monitoring for Cloud-Based Hydrogeological Modeling with HydroGeoSphere

Real-Time Environmental Monitoring for Cloud-Based Hydrogeol...

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IEEE International Conference on High Performance Computing and Communications (HPCC)

作者： Andrei Lapin Eryk Schiller Peter Kropf Oliver Schilling Philip Brunner Almerima Jamakovic Kapic Torsten Braun Sergio Maffioletti Computer Science Department (IIUN) Université de Neuchâtel Neuchâtel Switzerland Centre for Hydrogeology and Geothermics (CHYN) Université de Neuchâtel Neuchâtel Switzerland Universitat Bern Bern BE CH Communication and Distributed Systems Group (CDS) Universität Bern Bern Switzerland Universitat Zurich Zurich ZH CH

This paper describes an architecture for real-time environmental modeling. It consists of a wireless mesh network equipped with sensors and a cloud-based infrastructure to perform real-time environmental simulations using a physics-based model combined with an Ensemble Kalman Filter. The purpose of the system is to optimize groundwater abstraction close to a river. These initial studies demonstrate that the cloud infrastructure can simultaneously compute a large number of simulations, thus allowing for the implementation of Ensemble Kalman Filters in real-time.

关键词： Computational modeling Sensors Real-time systems Data models Predictive models Wireless sensor networks computer architecture

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A search-based approach for architectural design of feedback control concerns in Self-Adaptive systems

A search-based approach for architectural design of feedback...

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2013 IEEE 7th International Conference on Self-Adaptive and Self-Organizing systems, SASO 2013

作者： Andrade, Sandro S. De A. Macedo, Raimundo Jose GSORT Distributed Systems Group Federal Institute of Education Science and Technology of Bahia Salvador-Ba Brazil Department of Computer Science Federal University of Bahia Salvador-Ba Brazil

ISBN: (纸本)9780769551296

A number of approaches for endowing systems with self-Adaptive behavior have been proposed over the past years. Among such efforts, architecture-centric solutions with explicit representation of feedback loops have currently been advocated as a promising research landscape. Although noteworthy results have been achieved on some fronts, the lack of systematic representations of architectural knowledge and effective support for well-informed trade-off decisions still poses significant challenges when designing modern self-Adaptive systems. In this paper, we present a systematic and flexible representation of design dimensions related to feedback control concerns, a set of metrics which estimate quality attributes of resulting automated designs, and a search-based approach to find out a set of Pareto-optimal candidate architectures. The proposed approach has been fully implemented in a supporting tool and a case study with a self-Adaptive cloud computing environment has been undertaken. The results indicate that our approach effectively captures the most prominent degrees of freedom when designing self-Adaptive systems, helps to elicit effective subtle designs, and provides useful support for early analysis of trade-off decisions. © 2013 IEEE.

关键词： Economic and social effects

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Supporting environmental modelling with Taverna workflows, web services and desktop grid technology 7

Supporting environmental modelling with Taverna workflows, w...

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7th International Congress on Environmental Modelling and Software, iEMSs 2014

作者： Horváth, Ferenc Ittzés, Péter Ittzés, Dóra Barcza, Zoltán Dobor, Laura Hidy, Dóra Marosi, Attila Hardisty, Alex Institute of Ecology and Botany Centre for Ecological Research Hungarian Academy of Sciences Alkotmány u. 2-4. Vácrátót2163 Hungary Department of Meteorology Eötvös Loránd University Pázmány sétány 1/A Budapest1117 Hungary Institute of Botany and Ecophysiology Szent Istvan University Páter K. u.1. Gödöllo2100 Hungary Laboratory of Parallel and Distributed Systems Institute for Computer Science and Control Hungarian Academy of Sciences P.O. Box 63 Budapest1518 Hungary School of Computer Science and Informatics Cardiff University Queen's Buildings 5 The Parade Roath CardiffCF24 3AA United Kingdom

Ecosystem functioning, climate change, and multiple interactions among biogeochemical cycles, climate system, site conditions and land use options are leading-edge topics in recent environmental modelling. Terrestrial ecosystem models are widely used to support carbon sequestration and ecosystem studies under various ecological circumstances. Our team uses the Biome-BGC model (Numerical Terradynamic Simulation Group, University of Montana), and develops an improved model version of it, called Biome-BGC MuSo. Both the original and the improved model estimate the ecosystem scale storage and fluxes of energy, carbon, nitrogen and water, controlled by various physical and biological processes on a daily time-scale. Web services were also developed and integrated with parallel processing desktop grid technology. Taverna workflow management system was used to build up and carry out elaborated workflows like seamless data flow to model simulation, Monte Carlo experiment, model sensitivity analysis, model-data fusion, estimation of ecosystem service indicators or extensive spatial modelling. Straightforward management of complex data analysis tasks, organized into appropriately documented, shared and reusable scientific workflows enables researchers to carry out detailed and scientifically challenging 'in silico' experiments and applications that could open new directions in ecosystem research and in a broader sense it supports progress in environmental modelling. The workflow approach built upon these web services allows even the most complicated computations to be initiated without the need of programming skills and deep understanding of model structure and initialization. The developments enable a wider array of scientists to perform ecosystem scale simulations, and to perform analyses not previously possible due to high complexity and computational demand.

关键词： Web services

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Locality in continuous fitness-valued cases and genetic programming difficulty

Advances in Intelligent Systems and Computing

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Advances in Intelligent systems and Computing 2013年 175 ADVANCES卷 41-56页

作者： Galvan, Edgar Trujillo, Leonardo McDermott, James Kattan, Ahmed Distributed Systems Group School of Computer Science and Statistics Trinity College Dublin Ireland Departamento de Ingeniería Eléctrica y Electrónica Instituto Tecnológico de Tijuana Tijuana BC Mexico EvoDesignOpt MIT CSAIL Cambridge MA United States Computer Science Department Loughborough University Loughborough United Kingdom

ISBN: (纸本)9783642315183

It is commonly accepted that a mapping is local if it preserves neighbourhood. In Evolutionary Computation, locality is generally described as the property that neighbouring genotypes correspond to neighbouring phenotypes. Locality has been classified in one of two categories: high and low locality. It is said that a representation has high locality if most genotypic neighbours correspond to phenotypic neighbours. The opposite is true for a representation that has low locality. It is argued that a representation with high locality performs better in evolutionary search compared to a representation that has low locality. In this work, we explore, for the first time, a study on Genetic Programming (GP) locality in continuous fitnessvalued cases. For this, we extended the original definition of locality (first defined and used in Genetic Algorithms using bitstrings) from genotype-phenotype mapping to the genotype-fitness mapping. Then, we defined three possible variants of locality in GP regarding neighbourhood. The experimental tests presented here use a set of symbolic regression problems, two different encoding and two different mutation operators. We show how locality can be studied in this type of scenarios (continuous fitness-valued cases) and that locality can successfully been used as a performance prediction tool. © Springer-Verlag Berlin Heidelberg 2013.

关键词： Genetic programming

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IibARA: A framework for simulation and testbed based studies on ant routing algorithms in wireless multi-hop networks 7

IibARA: A framework for simulation and testbed based studies...

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7th International Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS 2013

作者： Frey, Michael Große, Friedrich Günes, Mesut Department of Computer Science Humboldt-Universität zu Berlin Unter den Linden 6 Berlin10099 Germany Distributed Embedded Systems Institute of Computer Science Freie Universität Berlin Takustrasse 9 Berlin14195 Germany

ISBN: (纸本)9781936968480

Routing in wireless multi-hop networks has been an active area of research over the last decade. Although, many test-beds were setup recently, the knowledge about the dynamic behavior of routing algorithms and the performance evaluation were mainly done via simulation. Simulation studies are imperative to understand important aspects of the algorithms, but are limited in certain aspects of the physical environment. Therefore, it is necessary to study routing algorithms also in a more realistic environment, in a testbed. Unfortunately, studying algorithms both in simulation and testbed raises multiple challenges. Particularly, the code base of the routing algorithm differ in both environments, which may lead to different behavior of the same routing algorithm. In this paper we introduce libARA, a framework that supports simulation and testbed experiments to study ant routing algorithms on the very same code base. Thus, the logic of the routing algorithm is the same, but works on two different environments. This is important to keep the results from both environments comparable and thus to increase the insight into the behavior of the algorithm. The main goal of the framework is to investigate the scalability and adaptability of ant routing algorithms. Copyright © 2013 ICST.

关键词： Routing algorithms

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On confidentiality-preserving real-time locking protocols

On confidentiality-preserving real-time locking protocols

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IEEE Symposium on Real-Time and Embedded Technology and Applications

作者： Marcus Völp Benjamin Engel Claude-Joachim Hamann Hermann Härtig Department of Computer Science Operating Systems Group Technische Universität Dresden Germany

Coordinating access to shared resources is a challenging task, in particular if real-time and security aspects have to be integrated into the same system. However, rather than exacerbating the problem, we found that considering real-time guarantees actually simplifies the security problem of preventing information leakage over shared-resource covert channels. We introduce a transformation for standard real-time resource locking protocols and show that protocols transformed in this way preserve the confidentiality guarantees of the schedulers on which they are based. Through this transformation, we were able to prove that four out of the seven investigated protocols are information-flow secure.

关键词： Protocols Schedules Real-time systems Timing Program processors Security Observers

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Approximating the geographical area of a wireless ad-hoc network

Approximating the geographical area of a wireless ad-hoc net...

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IEEE International Conference on Wireless and Mobile Computing, Networking And Communications (WiMob)

作者： Joanna Geibig Bratislav Milic Department of Parallel and Distributed Systems Zuse Institute Berlin Germany Department of Computer Science Humboldt University of Berlin Germany

Wireless ad-hoc networks are typically deployed in a decentralized way, without an authority that determines the location of nodes or the time they join the network. Additionally, existing nodes may fail during network lifetime. Consequently, the geographical span (area) of the network is irregular and unknown. However, if known, this information can be used to improve efficiency of many wireless applications; in some existing applications this information is necessary for their operation in the real use cases. For this purpose, we propose a distributed algorithm that determines the geographical network area. It is the first algorithm that simultaneously discovers network border, approximates the network area with a data structure of a constant size, and disseminates this information to all network nodes. Our algorithm uses only the nodes' local information, has a constant computational complexity and is resilient to link unreliability. The algorithm is evaluated by simulation on realistic network topologies of different sizes. The simulations demonstrate that the algorithm has high accuracy in its estimation of the network area, scales well with the number of nodes, and that it creates a low communication overhead.

关键词： Decision support systems Conferences Mobile communication Wireless communication Handheld computers

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Using an Agent-based Simulation for Predicting the Effects of Patients Derivation Policies in Emergency departments

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Procedia computer science 2013年 18卷 641-650页

作者： Manel Taboada Eduardo Cabrera Francisco Epelde Ma Luisa Iglesias Emilio Luque Tomas Cerda Computer Science School University Autonoma of Barcelona(UAB) Spain Computer Architecture and Operating Systems Department (CAOS) UAB Spain Hospital of Sabadell Consorci Sanitari Parc Taulí Barcelona Spain

The increasing demand of urgent care, overcrowding of hospital emergency departments (ED) and limited economic resources are phenomena shared by health systems around the world. It is estimated that up to 50% of patients that are attended in ED have non complex conditions that could be resolved in ambulatory care services. The derivation of less complex cases from the ED to other health care devices seems an essential measure to allocate properly the demand of care service between the different care units. This paper presents the results of an experiment carried out with the objective of analyzing the effects on the ED (patients’ Length of Stay, the number of patients attended and the level of activity of ED Staff) of different derivation policies. The experiment has been done with data of the Hospital of Sabadell (a big hospital, one of the most important in Catalonia, Spain), making use of an Agent-Based model and simulation formed entirely of the rules governing the behaviour of the individual agents which populate the ED, and due to the great amount of data that should be computed, using High Performance Computing.

关键词： Healthcare operational management Agent-based modelling Individual oriented simulation Emergency department Decision support systems

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