28 research outputs found

    Spring 2015 Vol. 14 No. 1

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    Spring 2015 Vol. 14 No. 1

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    https://surface.syr.edu/ischool_news/1018/thumbnail.jp

    Hardware Error Detection Using AN-Codes

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    Due to the continuously decreasing feature sizes and the increasing complexity of integrated circuits, commercial off-the-shelf (COTS) hardware is becoming less and less reliable. However, dedicated reliable hardware is expensive and usually slower than commodity hardware. Thus, economic pressure will most likely result in the usage of unreliable COTS hardware in safety-critical systems. The usage of unreliable, COTS hardware in safety-critical systems results in the need for software-implemented solutions for handling execution errors caused by this unreliable hardware. In this thesis, we provide techniques for detecting hardware errors that disturb the execution of a program. The detection provided facilitates handling of these errors, for example, by retry or graceful degradation. We realize the error detection by transforming unsafe programs that are not guaranteed to detect execution errors into safe programs that detect execution errors with a high probability. Therefore, we use arithmetic AN-, ANB-, ANBD-, and ANBDmem-codes. These codes detect errors that modify data during storage or transport and errors that disturb computations as well. Furthermore, the error detection provided is independent of the hardware used. We present the following novel encoding approaches: - Software Encoded Processing (SEP) that transforms an unsafe binary into a safe execution at runtime by applying an ANB-code, and - Compiler Encoded Processing (CEP) that applies encoding at compile time and provides different levels of safety by using different arithmetic codes. In contrast to existing encoding solutions, SEP and CEP allow to encode applications whose data and control flow is not completely predictable at compile time. For encoding, SEP and CEP use our set of encoded operations also presented in this thesis. To the best of our knowledge, we are the first ones that present the encoding of a complete RISC instruction set including boolean and bitwise logical operations, casts, unaligned loads and stores, shifts and arithmetic operations. Our evaluations show that encoding with SEP and CEP significantly reduces the amount of erroneous output caused by hardware errors. Furthermore, our evaluations show that, in contrast to replication-based approaches for detecting errors, arithmetic encoding facilitates the detection of permanent hardware errors. This increased reliability does not come for free. However, unexpectedly the runtime costs for the different arithmetic codes supported by CEP compared to redundancy increase only linearly, while the gained safety increases exponentially

    A Sensing Platform to Monitor Sleep Efficiency

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    Sleep plays a fundamental role in the human life. Sleep research is mainly focused on the understanding of the sleep patterns, stages and duration. An accurate sleep monitoring can detect early signs of sleep deprivation and insomnia consequentially implementing mechanisms for preventing and overcoming these problems. Recently, sleep monitoring has been achieved using wearable technologies, able to analyse also the body movements, but old people can encounter some difficulties in using and maintaining these devices. In this paper, we propose an unobtrusive sensing platform able to analyze body movements, infer sleep duration and awakenings occurred along the night, and evaluating the sleep efficiency index. To prove the feasibility of the suggested method we did a pilot trial in which several healthy users have been involved. The sensors were installed within the bed and, on each day, each user was administered with the Groningen Sleep Quality Scale questionnaire to evaluate the user’s perceived sleep quality. Finally, we show potential correlation between a perceived evaluation with an objective index as the sleep efficiency.</p

    LDEF Materials Results for Spacecraft Applications

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    These proceedings describe the application of LDEF data to spacecraft and payload design, and emphasize where space environmental effects on materials research and development is needed as defined by LDEF data. The LDEF six years of exposure of materials has proven to be by far the most comprehensive source of information ever obtained on the long-term performance of materials in the space environment. The conference provided a forum for materials scientists and engineers to review and critically assess the LDEF results from the standpoint of their relevance, significance, and impact on spacecraft design practice. The impact of the LDEF findings on materials selection and qualification, and the needs and plans for further study, were addressed from several perspectives. Many timely and needed changes and modifications in external spacecraft materials selection have occurred as a result of LDEF investigations

    Towards cooperative software verification with test generation and formal verification

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    There are two major methods for software verification: testing and formal verification. To increase our confidence in software on a large scale, we require tools that apply these methods automatically and reliably. Testing with manually written tests is widespread, but for automatically generated tests for the C programming language there is no standardized format. This makes the use and comparison of automated test generators expensive. In addition, testing can never provide full confidence in software—it can show the presence of bugs, but not their absence. In contrast, formal verification uses established, standardized formats and can prove the absence of bugs. Unfortunately, even successful formal-verification techniques suffer from different weaknesses. Compositions of multiple techniques try to combine the strengths of complementing techniques, but such combinations are often designed as cohesive, monolithic units. This makes them inflexible and it is costly to replace components. To improve on this state of the art, we work towards an off-the-shelf cooperation between verification tools through standardized exchange formats. First, we work towards standardization of automated test generation for C. We increase the comparability of test generators through a common benchmarking framework and reliable tooling, and provide means to reliably compare the bug-finding capabilities of test generators and formal verifiers. Second, we introduce new concepts for the off-the-shelf cooperation between verifiers (both test generators and formal verifiers). We show the flexibility of these concepts through an array of combinations and through an application to incremental verification. We also show how existing, strongly coupled techniques in software verification can be decomposed into stand-alone components that cooperate through clearly defined interfaces and standardized exchange formats. All our work is backed by rigorous implementation of the proposed concepts and thorough experimental evaluations that demonstrate the benefits of our work. Through these means we are able to improve the comparability of automated verifiers, allow the cooperation between a large array of existing verifiers, increase the effectiveness of software verification, and create new opportunities for further research on cooperative verification

    UNVEILING SENSORY MECHANISMS FOR THE CONTROL OF TWO INSECT PESTS: FROM BEHAVIOR TO MOLECULAR INTERACTIONS

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    Pest control strategies targeting insect olfaction represent a promising venue for control of tortricid insects (Lepidoptera: Tortricidae). Among tortricids, the grapevine moth Lobesia botrana (Denis and Schifferm\ufcller) and the codling moth Cydia pomonella (L.) are serious pests for worldwide production of fruit crops. We employed several approaches to the olfactory system, from electrophysiological and behavioral studies in the grapevine moth, to bioinformatic and molecular studies of olfactory sensory proteins in the codling moth. At the receptor level, we studied both the Olfactory Receptors (ORs), the most common class of sensory proteins mediating detection of odors in insect antennae, and the Transient Receptor Potential (TRP) channels, a novel family of receptor, that recently were also found in the antennae of lepidopterous species. We demonstrated electrophysiological and behavioral responses of the grapevine moth to volatiles emitted by a non-host, Perilla frutescens, previously known to activate TRPs in the rat, Rattus norvegicus. In the codling moth, we characterized a novel TRP channel (TRPA pyrexia-like) and we confirmed activation of its human orthologue to the same non-host compounds active on the olfactory system of the grapevine moth. ORs were heterologously expressed in vivo and in vitro, for identification of their ligands among host and non-host plant volatiles and pheromones (deorphanization). Among several ORs of codling moth, we deorphanized a candidate pheromone receptor (PR) to plant synergists, an OR to non-host volatiles and another PR candidate to a pheromone antagonist of the insect. Our study thus opens for refinement of existing pest control, or novel applications. The behavioral response of the grapevine moth to volatiles from a nonhost plant, and the identification of a novel TRP channel in the codling moth may have perspectives for application in agriculture, targeting the somatosensory system of these tortricids. The evolutionary implications of the responses of the human orthologue of TRPA pyrexia-like to volatiles active on the grapevine moth olfactory system could imply a large degree of conservation of the receptor function. In the codling moth, identification of synergist and antagonist ligands for candidate PRs and deorphanization of an OR to non-host plant volatiles suggest a possible role of these receptors in reproductive and ecological isolation. This could lead to further refinement of existing semiochemicalbased control techniques, by enabling a better understanding of mate- and host-finding in this species
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