777 research outputs found

    Effects of freezing on ram and boar sperm

    Get PDF
    Sperm survival in frozen semen appears to be determined largely by the amount of intracellular enzymes during freezing and thawing. Data is presented to show the effects of different diluents, temperature and glycerol as well as egg yolk concentrations, on glutamic-oxaloacetic-transaminase release.Thesis (M.Ag.Sc.) -- University of Adelaide, Dept. of Animal Physiology, 197

    Protecting Temporal Fingerprints with Synchronized Chaotic Circuits

    Get PDF
    In recent years, connected autonomous vehicles (CAVs) feature an increasing number of Ethernet-enabled electronic control units (ECUs), thereby creating more threat vectors that provide access to the Controller Area Network (CAN) Bus. Currently, mitigation techniques to protect the CAN bus from compromised ECU units in vehicle ad hoc networks (VANET) often utilize classical cryptographic techniques. However, ECUs often have temporal signatures that leak internal state information to eavesdropping attackers who can leverage temporal properties for longitudinal attacks. Unfortunately, these types of attacks are difficult to defend against using classical encryption schemes and intrusion detection systems (IDS) due to their high computational demands and ineffectiveness at protecting CAVs throughout the duration of their long lifespans. In order to address these problems, we propose a novel cryptographic framework that protects information embedded in ECU network communications by delivering an encryption system that periodically salts the temporal dynamics of individual ECU units with chaotic signals that are difficult to learn. We demonstrate the framework on two datasets, and our results show that the underlying temporal signatures cannot be approximated by state-of-the-art learning algorithms over finite time horizons

    Measuring Confidence of Assurance Cases in Safety-Critical Domains

    Get PDF
    Evaluation of assurance cases typically requires certifiers’ domain knowledge and experience, and, as such, most software certification has been conducted manually. Given the advancement in uncertainty theories and software traceability, we envision that these technologies can synergistically be combined and leveraged to offer some degree of automation to improve the certifiers’ capability to perform software certification. To this end, we present DS4AC, a novel confidence calculation framework that 1) applies the Dempster-Shafer theory to calculate the confidence between a parent claim and its children claims; and 2) uses the vector space model to evaluate the confidence for the evidence items using traceability information. We illustrate our approach on two different applications, where safety is the key property of interest for both systems. In both cases, we use the Goal Structuring Notation to represent the respective assurance cases and provide proof of concept results that demonstrate the DS4AC framework can automate portions of the evaluation of assurance cases, thereby reducing the burden of manual certification process

    08031 Abstracts Collection -- Software Engineering for Self-Adaptive Systems

    Get PDF
    From 13.01. to 18.01.2008, the Dagstuhl Seminar 08031 ``Software Engineering for Self-Adaptive Systems\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

    RELAX:a language to address uncertainty in self-adaptive systems requirement

    Get PDF
    Self-adaptive systems have the capability to autonomously modify their behavior at run-time in response to changes in their environment. Self-adaptation is particularly necessary for applications that must run continuously, even under adverse conditions and changing requirements; sample domains include automotive systems, telecommunications, and environmental monitoring systems. While a few techniques have been developed to support the monitoring and analysis of requirements for adaptive systems, limited attention has been paid to the actual creation and specication of requirements of self-adaptive systems. As a result, self-adaptivity is often constructed in an ad-hoc manner. In order to support the rigorous specication of adaptive systems requirements, this paper introduces RELAX, a new requirements language for self- adaptive systems that explicitly addresses uncertainty inherent in adaptive systems. We present the formal semantics for RELAX in terms of fuzzy logic, thus enabling a rigorous treatment of requirements that include uncertainty. RELAX enables developers to identify uncertainty in the requirements, thereby facilitating the design of systems that are, by denition, more exible and amenable to adaptation in a systematic fashion. We illustrate the use of RELAX on smart home applications, including an adaptive assisted living system

    Automatically generating adaptive logic to balance non-functional tradeoffs during reconfiguration

    Get PDF
    Increasingly, high-assurance software systems apply selfreconfiguration in order to satisfy changing functional and non-functional requirements. Most self-reconfiguration approaches identify a target system configuration to provide the desired system behavior, then apply a series of reconfiguration instructions to reach the desired target configuration. Collectively, these reconfiguration instructions define an adaptation path. Although multiple satisfying adaptation paths may exist, most self-reconfiguration approaches select adaptation paths based on a single criterion, such as minimizing reconfiguration cost. However, different adaptation paths may represent tradeoffs between reconfiguration costs and other criteria, such as performance and reliability. This paper introduces an evolutionary computationbased approach to automatically evolve adaptation paths that safely transition an executing system from its current configuration to its desired target configuration, while balancing tradeoffs between functional and non-functional requirements. The proposed approach can be applied both at design time to generate suites of adaptation paths, as well as at run time to evolve safe adaptation paths to handle changing system and environmental conditions. We demonstrate the effectiveness of this approach by applying it to the dynamic reconfiguration of a collection of remote data mirrors, with the goal of minimizing reconfiguration costs while maximizing reconfiguration performance and reliability

    User Experience for Model-Driven Engineering : Challenges and Future Directions

    Get PDF
    Since its infancy, Model Driven Engineering (MDE) research has primarily focused on technical issues. Although it is becoming increasingly common for MDE research papers to evaluate their theoretical and practical solutions, extensive usability studies are still uncommon. We observe a scarcity of User eXperience (UX)-related research in the MDE community, and posit that many existing tools and languages have room for improvement with respect to UX [26], [44], [37], where UX is a key focus area in the software development industry. We consider this gap a fundamental problem that needs to be addressed by the community if MDE is to gain widespread use. In this vision paper, we explore how and where UX fits into MDE by considering motivating use cases that revolve around different dimensions of integration: model integration, tool integration, and integration between process and tool support. Based on the literature and our collective experience in research and industrial collaborations, we propose future directions for addressing these challenges

    Addressing the Uncertainty Interaction Problem in Software-intensive Systems: Challenges and Desiderata. (Summary).

    Get PDF
    Software-intensive systems are increasingly used to support tasks that are typically characterized by high degrees of uncertainty. The modeling notations employed to design, verify, and operate such systems have increasingly started to capture different types of uncertainty, so that they can be explicitly considered when systems are developed and deployed. While these modeling paradigms consider different sources of uncertainty individually, these sources are rarely independent, and their interactions affect the achievement of system goals in subtle and often unpredictable ways. This vision paper describes the problem of uncertainty interaction in software-intensive systems, illustrating it on examples from relevant application domains. We then identify key open challenges that require further exploration, and define desiderata that future modeling notations and model-driven engineering research should consider to address these challenges.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech

    Hepatitis C Virus Genotype 4 in Ugandan Children and Their Mothers

    Get PDF
    In Kampala, Uganda, in 2001, hepatitis C virus antibodies were found in 27 (4%) of 603 children and in 62 (12%) of 525 of their mothers. However, only ≈10% of positive results were confirmed by reverse transcription–PCR, which suggests frequent false-positive results or viral clearance. All sequenced types were genotype 4
    • 

    corecore