55 research outputs found

    Radio frequency communication and fault detection for railway signalling

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    The continuous and swift progression of both wireless and wired communication technologies in today's world owes its success to the foundational systems established earlier. These systems serve as the building blocks that enable the enhancement of services to cater to evolving requirements. Studying the vulnerabilities of previously designed systems and their current usage leads to the development of new communication technologies replacing the old ones such as GSM-R in the railway field. The current industrial research has a specific focus on finding an appropriate telecommunication solution for railway communications that will replace the GSM-R standard which will be switched off in the next years. Various standardization organizations are currently exploring and designing a radiofrequency technology based standard solution to serve railway communications in the form of FRMCS (Future Railway Mobile Communication System) to substitute the current GSM-R. Bearing on this topic, the primary strategic objective of the research is to assess the feasibility to leverage on the current public network technologies such as LTE to cater to mission and safety critical communication for low density lines. The research aims to identify the constraints, define a service level agreement with telecom operators, and establish the necessary implementations to make the system as reliable as possible over an open and public network, while considering safety and cybersecurity aspects. The LTE infrastructure would be utilized to transmit the vital data for the communication of a railway system and to gather and transmit all the field measurements to the control room for maintenance purposes. Given the significance of maintenance activities in the railway sector, the ongoing research includes the implementation of a machine learning algorithm to detect railway equipment faults, reducing time and human analysis errors due to the large volume of measurements from the field

    Computer Aided Verification

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    This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency

    Recent Development of Hybrid Renewable Energy Systems

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    Abstract: The use of renewable energies continues to increase. However, the energy obtained from renewable resources is variable over time. The amount of energy produced from the renewable energy sources (RES) over time depends on the meteorological conditions of the region chosen, the season, the relief, etc. So, variable power and nonguaranteed energy produced by renewable sources implies intermittence of the grid. The key lies in supply sources integrated to a hybrid system (HS)

    Using a PVS embedding of CSP to verify authentication protocols

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    Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm

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    Abstract— Online transportation has become a basic requirement of the general public in support of all activities to go to work, school or vacation to the sights. Public transportation services compete to provide the best service so that consumers feel comfortable using the services offered, so that all activities are noticed, one of them is the search for the shortest route in picking the buyer or delivering to the destination. Node Combination method can minimize memory usage and this methode is more optimal when compared to A* and Ant Colony in the shortest route search like Dijkstra algorithm, but can’t store the history node that has been passed. Therefore, using node combination algorithm is very good in searching the shortest distance is not the shortest route. This paper is structured to modify the node combination algorithm to solve the problem of finding the shortest route at the dynamic location obtained from the transport fleet by displaying the nodes that have the shortest distance and will be implemented in the geographic information system in the form of map to facilitate the use of the system. Keywords— Shortest Path, Algorithm Dijkstra, Node Combination, Dynamic Location (key words

    A UTP semantics for communicating processes with shared variables and its formal encoding in PVS

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    CSP# (communicating sequential programs) is a modelling language designed for specifying concurrent systems by integrating CSP-like compositional operators with sequential programs updating shared variables. In this work, we define an observation-oriented denotational semantics in an open environment for the CSP# language based on the UTP framework. To deal with shared variables, we lift traditional event-based traces into mixed traces which consist of state-event pairs for recording process behaviours. To capture all possible concurrency behaviours between action/channel-based communications and global shared variables, we construct a comprehensive set of rules on merging traces from processes which run in parallel/interleaving. We also define refinement to check process equivalence and present a set of algebraic laws which are established based on our denotational semantics. We further encode our proposed denotational semantics into the PVS theorem prover. The encoding not only ensures the semantic consistency, but also builds up a theoretic foundation for machine-assisted verification of CSP# specifications.Full Tex

    Verifying a signature architecture: a comparative case study

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    We report on a case study in applying different formal methods to model and verify an architecture for administrating digital signatures. The architecture comprises several concurrently executing systems that authenticate users and generate and store digital signatures by passing security relevant data through a tightly controlled interface. The architecture is interesting from a formal-methods perspective as it involves complex operations on data as well as process coordination and hence is a candidate for both data-oriented and process-oriented formal methods. We have built and verified two models of the signature architecture using two representative formal methods. In the first, we specify a data model of the architecture in Z that we extend to a trace model and interactively verify by theorem proving. In the second, we model the architecture as a system of communicating processes that we verify by finite-state model checking. We provide a detailed comparison of these two different approaches to formalization (infinite state with rich data types versus finite state) and verification (theorem proving versus model checking). Contrary to common belief, our case study suggests that Z is well suited for temporal reasoning about process models with complex operations on data. Moreover, our comparison highlights the advantages of proving theorems about such models and provides evidence that, in the hands of an experienced user, theorem proving may be neither substantially more time-consuming nor more complex than model checkin

    Export regulation, import safety? EU public and private motivations to influence China’s food safety regulation

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    The globalization of food production has increased the probability for markets to import unsafe food. Against this backdrop, in December 2001 China joined the World Trade Organisation (WTO). With this step the country effectively became part of the globalized food production. This study analyses how the European Union (EU) – understood as an entity comprising public as well as private actors – responded to this challenge. More specifically, the objective is to understand the motivation behind the EU’s observed activities to influence China’s food safety regulation. Two hypotheses are deduced from theories of regulatory interdependence. The first assumes a supply safety hypothesis. With its massive food safety problems, China quickly posed risks to global food safety and thus also to EU’s food safety. This happened at a time, when the EU itself had reinforced its food safety regulation with a stronger focus on consumer interests. Any influence by EU actors on China’s food safety regulation thus could be the result of heightened import safety concerns. The second hypothesis offers an alternative explanation. China presents an attractive export market for EU companies. Although lagging behind the internationally established benchmark for safety, China’s food safety regulation still potentially created market entry barriers for EU food exports. Activities to influence China’s food safety regulation hence could be based on the interest to reduce such regulatory barriers to trade. Based on a mechanistic understanding of causality and the method of process tracing, this study specifies which combination of both motivations explains the observed activities by EU actors to influence China’s food safety regulation between 2001 and 2014
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