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Particulate matter (PM) pollution is responsible for hundreds of thousands of deaths worldwide, the majority due to cardiovascular disease (CVD). While many potential pathophysiological mechanisms have been proposed, there is not yet a consensus as to which are most important in causing pollution-related morbidity/mortality. Nor is there consensus regarding which specific types of PM are most likely to affect public health in this regard. One toxicological mechanism linking exposure to airborne PM with CVD outcomes is oxidative stress, a contributor to the development of CVD risk factors including atherosclerosis. Recent work suggests that accelerated shortening of telomeres and, thus, early senescence of cells may be an important pathway by which oxidative stress may accelerate biological aging and the resultant development of age-related morbidity. This pathway may explain a significant proportion of PM-related adverse health outcomes, since shortened telomeres accelerate the progression of many diseases. There is limited but consistent evidence that vehicular emissions produce oxidative stress in humans. Given that oxidative stress is associated with accelerated erosion of telomeres, and that shortened telomeres are linked with acceleration of biological ageing and greater incidence of various age-related pathology, including CVD, it is hypothesized that associations noted between certain pollution types and sources and oxidative stress may reflect a mechanism by which these pollutants result in CVD-related morbidity and mortality, namely accelerated aging via enhanced erosion of telomeres. This paper reviews the literature providing links among oxidative stress, accelerated erosion of telomeres, CVD, and specific sources and types of air pollutants. If certain PM species/sources might be responsible for adverse health outcomes via the proposed mechanism, perhaps the pathway to reducing mortality/morbidity from PM would become clearer. Not only would pollution reduction imperatives be more focused, but interventions which could reduce oxidative stress would become all the more important.  相似文献   
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In an earlier work, aThreshold Scheduling Algorithmwas proposed to schedule the functional (DAG) parallelism in a program on distributed memory systems. In this work, we address the issue of adapting the schedule for a set of distributed memory architectures with the same computation costs but higher communication costs. We introduce a new concept ofdominant edgesof a schedule to denote those edges which dictate the schedule time of the destination nodes due to the changes in their communication costs. Using this concept, we derive the conditions under which schedule on the whole or at least part of the graph can be reused for a different architecture keeping the cost of program repartitioning and rescheduling to a minimum. We demonstrate the practical significance of the method by incorporating it in the compiler backend for targeting Sisal (Streams and Iterations in a Single Assignment Language) on a family of Intel i860 architectures, Gamma, Delta, and Paragon, which vary in their communication costs. It is shown that almost 30 to 65% of the schedule can be reused unchanged, thereby avoiding program repartitioning to a large degree. The remainder of the schedule can beregeneratedthrough a linear algorithm at run time.  相似文献   
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The GCD test and the Banerjee–Wolfe test are the two tests traditionally used to determine statement data dependence, subject to direction vectors, in automatic vectorization/parallelization of loops. In an earlier study, a sufficient condition for the accuracy of the Banerjee–Wolfe test was stated and proved. In that work, we only considered the case of general data dependence, i.e., the case of data dependence without direction vector information. In this paper, we extend the previous result to the case of data dependence subject to an arbitrary direction vector. We also state and prove a sufficient condition for the accuracy of a combination of the GCD and Banerjee–Wolfe tests. Furthermore, we show that the sufficient conditions, for the accuracy of the Banerjee–Wolfe test and the accuracy of a combination of the GCD and Banerjee–Wolfe tests are necessary conditions as well. Finally, we demonstrate how these results can be used in actual practice to obtain exact data dependence information.  相似文献   
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The function block (FB) concept has been adopted by recent International Electrotechnical Commission (IEC) standards to define a methodology for the development of modular, re-usable, open, and vendor-independent distributed control applications. Control engineers are already familiar with the FB construct, and field devices and fieldbuses are expected to be compliant with this approach in the near future. New generation FB-oriented CASE tools are required to support the whole development process. This paper presents an approach to the design and development of an IEC-compliant CASE tool (ICT). The proposed approach is based on a four-layer architecture that successfully unifies the FB concept with the Unified Modelling Language. During the development of our prototype ICT, this architecture proved to be very significant for the identification of the key abstractions that the ICT must provide as building blocks of its various diagrams used during the modelling process of control systems.  相似文献   
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Advances in information technology and knowledge management change the way that e-negotiations, which constitute an important aspect of worldwide e-trading, can be structured and represented. In this paper, a novel approach that focuses on knowledge modeling, formalization, representation and management in the domain of e-negotiation is described. The proposed approach exploits Ontologies, Service Oriented Architectures, Semantic Web Services, software agent platforms, and Knowledge-Bases to construct a framework that favors dynamically adapted negotiation protocols, negotiation process visualization and management, modeling and preference elicitation of the negotiated object and automatic deployment of negotiation interfaces. Negotiation process, protocol and strategy are examined, and a hybrid approach that integrates rules and workflow diagrams to describe and represent them is introduced.  相似文献   
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Verification of IEC 61131-3 based safety applications is a challenge in the industrial automation domain. In this paper, the transformation of FBD diagrams to UPPAAL formal models was adopted to address this challenge. A set of transformation rules are defined for the automatic transformation of IEC 61131-3 Function Block based safety applications to UPPAAL timed automata models. These models are next used for the verification of the safety application. Both the source and the target domain models have been formally defined and these definitions are used for the definition of the transformation rules. Based on this a prototype model transformer was developed using Java. The transformer was used with various safety applications to check the efficiency of the transformation process. A laboratory system is presented as a case study to highlight the proposed approach.  相似文献   
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