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991.
在目前的版本管理系统中,主要提供面向文件的版本管理,把文件作为管理对象的核心,管理产品零件某个版本相关的各种数据,包括CAD模型、各种文档等。版本属性主要反映产品的外部属性信息,不能提供版本的内部知识以及文件之间在内容上的区别和联系。设计知识共享是企业开发新产品、增强竞争力的关键。根据版本设计信息,采用面向对象记述,建立版本知识体系和获取机制,并实现了一种基于设计知识的版本管理方法。 相似文献
992.
993.
J. Fuhrer 《臭氧:科学与工程》2002,24(1):69-74
During the past 50 years, phytotoxic effects of tropospheric ozone on plants have been observed over large areas of the northern hemisphere. The present review highlights some important aspects of the interaction between tropospheric ozone and plants. These include the transfer of ozone from the air to the site of action inside the leaves, primary reactions at the cell membrane, metabolic disturbances, and resulting effects on plant growth. Based on experimental exposure-response relationships, the ozone risk for vegetation can be assessed; in Europe, these assessments suggest widespread impacts of short-term and long-term ozone exposure on plants under well-irrigated conditions. 相似文献
994.
Along with the explosive increase of product data management systems (PDMs),integrating polymorphic PDMs is becoming one of the focuses in the field. Aner brief describing several features of PDM, and market requirements and required performance for integrating the polymorphic PDMs, the paper specializes in discussing some key technologies involved in virtual enterprise oriented integrated development. Some implementing strategies and procedures are proposed. 相似文献
995.
According to the Environmental Protection Agency (EPA) and other public health agencies in the United States, radon may be the leading cause (along with passive smoking) of lung cancer deaths among nonsmokers. Radon is estimated to be the second leading cause of lung cancer death in smokers behind smoking-related lung cancer. EPA estimates that 7,000 to 30,000 lung cancer deaths each year are due to radon exposure. (It is implied that radon-related lung cancer deaths can be prevented by reducing radon levels below EPA's guideline levels.) Current EPA radon policy is based on a strategy of education, the transfer of testing and remediation technologies to the public and private sectors, and recently proposed radon-resistant construction standards for new homes. This paper models the effectiveness of current, proposed, and alternative policies for reducing radon risks in U.S. residential construction. The results of our analysis suggest that EPA's projections of 2,200 “lives saved annually” as a result of its current action level of 4 pCi/l will not be achieved with its current policy in the near future. Overall, the response of radon-related mortality to most policy options is delayed and flat due in pan to the large number of houses with low radon levels and the long latency period between radon exposure and the development of cancer. The modeling results suggest that more aggressive smoking reduction programs may yield greater benefits in overall lung cancer mortality (but not reduced radon exposure) than most radon-related policies. 相似文献
996.
本文讨论了建立科学的辐射防护管理体系问题。科学的辐射防护管理体系包括:明确的管理目标,完整的数据登记、统计和报告制度,严格的监督制度和科学的管理方法学。 相似文献
997.
Richard Wood 《河流研究与利用》1988,2(3):471-477
Integrated river basin management has been the backcloth against which river regulation has been practiced in England and Wales for the past 14 years. Its success is reviewed and the forthcoming changes in legislation are critically examined. A number of problems facing the emergent National Rivers Authority are discussed. The need for co-operation rather than conflict is advocated wherever environment is to be protected and when competing pressures impact on river resources. A number of technical issues remain unresolved and the need for continuing work is recognized. 相似文献
998.
This paper presents practical experience in planning, implementing, and adopting a Quality Management System (QMS) for embedded systems development at VTT Electronics. The main objective for the development of the QMS was to make it practical for real-life embedded systems research and development (R&D) projects. We have applied the ISO 9001 standard and ISO 9000–3 guidelines in building the quality system. From our personnel's point of view, the most important parts of the system have been document skeletons and plan templates that were made accessible to everyone. One of the major quality improvement resulting from the use of the QMS has been the enhanced predictability of R&D projects. This makes it possible for the organization to concentrate on essential matters. From our clients' point of view, we have clearly improved the quality of our R&D services in terms of the customer satisfaction index. Based on QMS auditing activities, we have been able to evaluate and tune our R&D procedures in a systematic manner. We have decided to use Total Quality Management and Quality Award frameworks in the further development of the QMS. Customer service and human resources management are examples of important areas for further quality improvement. 相似文献
999.
Ball DJ 《Accident; analysis and prevention》2004,36(4):661-670
The case for the universal application of 'safer surfacing' in playgrounds is assessed in terms of absolute risk, cost-benefit, and qualitative factors, and found to be open to question on each front. In parallel, it is noted that members of the child welfare and play communities are increasingly of the view that playgrounds are losing their appeal for children, which in turn has its own health, safety and developmental consequences. In part, this loss of attractiveness may have linkages with the recent concern over play safety and the imposition of measures such as 'safer surfacing'. It is proposed that the drive for play safety, which has existed for some 20 years, should be succeeded by a more holistic approach which, rather than considering play safety in isolation, acknowledges the importance of all attributes of play including child safety both on and off playgrounds, potential beneficial aspects of childhood risk exposure, adventure, and play value. 相似文献
1000.