3,320 research outputs found

    Process evaluation of five integrated offender management pioneer areas

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    A qualitative process evaluation of five Integrated Offender Management (IOM) pioneer areas was undertaken to assess implementation of IOM, identify approaches to implementation and capture the lessons learnt. The findings indicated that IOM enabled structural changes, transforming the delivery of offender management. There was considerable commitment and enthusiasm for IOM at the sites, whilst acknowledging barriers to development such as definition, resourcing, governance and clarity of agency roles. Since the evaluation took place, the political and criminal justice landscape has changed somewhat, supporting a more locally driven approach which can draw on the learning directly from the pioneers which were shaped and delivered locally

    Modelling Smart Card Security Protocols in SystemC TLM

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    Smart cards are an example of advanced chip technology. They allow information transfer between the card holder and the system over secure networks, but they contain sensitive data related to both the card holder and the system, that has to be kept private and confidential. The objective of this work is to create an executable model of a smart card system, including the security protocols and transactions, and to examine the strengths and determine the weaknesses by running tests on the model. The security objectives have to be considered during the early stages of systems development and design, an executable model will give the designer the advantage of exploring the vulnerabilities early, and therefore enhancing the system security. The Unified Modeling Language (UML) 2.0 is used to model the smart card security protocol. The executable model is programmed in SystemC with the Transaction Level Modeling (TLM) extensions. The final model was used to examine the effectiveness of a number of authentication mechanisms with different probabilities of failure. In addition, a number of probable attacks on the current security protocol were modeled to examine the vulnerabilities. The executable model shows that the smart card system security protocols and transactions need further improvement to withstand different types of security attacks

    On Asynchronous Session Semantics

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    This paper studies a behavioural theory of the π-calculus with session types under the fundamental principles of the practice of distributed computing — asynchronous communication which is order-preserving inside each connection (session), augmented with asynchronous inspection of events (message arrivals). A new theory of bisimulations is introduced, distinct from either standard asynchronous or synchronous bisimilarity, accurately capturing the semantic nature of session-based asynchronously communicating processes augmented with event primitives. The bisimilarity coincides with the reduction-closed barbed congruence. We examine its properties and compare them with existing semantics. Using the behavioural theory, we verify that the program transformation of multithreaded into event-driven session based processes, using Lauer-Needham duality, is type and semantic preserving

    Correct and Efficient Antichain Algorithms for Refinement Checking

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    The notion of refinement plays an important role in software engineering. It is the basis of a stepwise development methodology in which the correctness of a system can be established by proving, or computing, that a system refines its specification. Wang et al. describe algorithms based on antichains for efficiently deciding trace refinement, stable failures refinement and failures-divergences refinement. We identify several issues pertaining to the soundness and performance in these algorithms and propose new, correct, antichain-based algorithms. Using a number of experiments we show that our algorithms outperform the original ones in terms of running time and memory usage. Furthermore, we show that additional run time improvements can be obtained by applying divergence-preserving branching bisimulation minimisation

    Automated reasoning on feature models

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    Software Product Line (SPL) Engineering has proved to be an effective method for software production. However, in the SPL community it is well recognized that variability in SPLs is increasing by the thousands. Hence, an automatic support is needed to deal with variability in SPL. Most of the current proposals for automatic reasoning on SPL are not devised to cope with extra– functional features. In this paper we introduce a proposal to model and reason on an SPL using constraint programming. We take into account functional and extra–functional features, improve current proposals and present a running, yet feasible implementation

    Developing a distributed electronic health-record store for India

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    The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India

    Impact of an interatrial shunt device on survival and heart failure hospitalization in patients with preserved ejection fraction

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    Aims: Impaired left ventricular diastolic function leading to elevated left atrial pressures, particularly during exertion, is a key driver of symptoms and outcomes in heart failure with preserved ejection fraction (HFpEF). Insertion of an interatrial shunt device (IASD) to reduce left atrial pressure in HFpEF has been shown to be associated with short‐term haemodynamic and symptomatic benefit. We aimed to investigate the potential effects of IASD placement on HFpEF survival and heart failure hospitalization (HFH). Methods and results: Heart failure with preserved ejection fraction patients participating in the Reduce Elevated Left Atrial Pressure in Patients with Heart Failure study (Corvia Medical) of an IASD were followed for a median duration of 739 days. The theoretical impact of IASD implantation on HFpEF mortality was investigated by comparing the observed survival of the study cohort with the survival predicted from baseline data using the Meta‐analysis Global Group in Chronic Heart Failure heart failure risk survival score. Baseline and post‐IASD implant parameters associated with HFH were also investigated. Based upon the individual baseline demographic and cardiovascular profile of the study cohort, the Meta‐analysis Global Group in Chronic Heart Failure score‐predicted mortality was 10.2/100 pt years. The observed mortality rate of the IASD‐treated cohort was 3.4/100 pt years, representing a 33% lower rate (P = 0.02). By Kaplan–Meier analysis, the observed survival in IASD patients was greater than predicted (P = 0.014). Baseline parameters were not predictive of future HFH events; however, poorer exercise tolerance and a higher workload‐corrected exercise pulmonary capillary wedge pressure at the 6 months post‐IASD study were associated with HFH. Conclusions: The current study suggests IASD implantation may be associated with a reduction in mortality in HFpEF. Large‐scale ongoing randomized studies are required to confirm the potential benefit of this therapy
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