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一种适合于网络专家系统的通用理论(英文)   总被引:1,自引:0,他引:1  
描述运用于工业自动化的一种自适应自学习方法。基于此方法,Aptronix公司开发出一套通用软件工具-STIMTM,并应用于不同工业领域。STIM可用于构造各类专家系统。基于因素空间理论,STIM具有一系列独特之处,比如自动化、自学习,以及自翻译。如果与因特网,嵌入式控制器以及可编程逻辑控制器等结合使用,STIM则成为一个十分有效的工具,可应用于远程连通与控制、模式识别、机器故障诊断,以及自动化加工过程中的传感器数据融合  相似文献   
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The main purpose of this paper is to exposit two very different, but very general, motivational schemes in the art of parameterization and a concrete example connecting them. We introduce a dynamic version of the DOMINATING SET problem and prove that it is fixed-parameter tractable(FPT). The problem is motivated by settings where problem instances evolve. It also arises in the quest to improve a natural greedy heuristic for the DOMINATING SET problem.  相似文献   
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The floristic composition of the Lee Creek valley in southwestern Alberta, Canada, is presented. The valley flora consists of 299 species of vascular plants representing 173 genera and 46 families. The flora is dominated by forbs (73 percent), followed by grasses (24 percent), shrubs (12 percent), and trees (11 percent). The valley of Lee Creek is divided into upper and lower sections on the basis of elevational, climatic, and biotic differences. Floristic richness of the Lee Creek valley is quite evenly divided between the upper and lower valleys: 105 species limited to the upper valley, 95 to the lower valley, and 99 species shared by both upper and lower valleys.  相似文献   
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The 2004-based national population projections, carried out by the Government Actuary in consultation with the Registrars General, show the population of the United Kingdom (UK) rising from 59.8 million in 2004, passing 60 million in 2005 and 65 million in 2023, to reach 67.0 million by 2031. In the longer-term, the projections suggest that the population will continue rising beyond 2031 but at a much lower rate of growth. The population will become older with the median age expected to rise from 38.6 years in 2004 to 42.9 years by 2031. With the current plans for a common state pension age of 65 for both sexes from 2020, the number of people of working age for every person of state pensionable age is projected to fall from 3.33 in 2004 to 2.62 by 2031.  相似文献   
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Human infection by genetically diverse SIVSM-related HIV-2 in west Africa.   总被引:41,自引:0,他引:41  
Our understanding of the biology and origins of human immunodeficiency virus type 2 (HIV-2) derives from studies of cultured isolates from urban populations experiencing epidemic infection and disease. To test the hypothesis that such isolates might represent only a subset of a larger, genetically more diverse group of viruses, we used nested polymerase chain reactions to characterize HIV-2 sequences in uncultured mononuclear blood cells of two healthy Liberian agricultural workers, from whom virus isolation was repeatedly unsuccessful, and from a culture-positive symptomatic urban dweller. Analysis of pol, env and long terminal repeat regions revealed the presence of three highly divergent HIV-2 strains, one of which (from one of the healthy subjects) was significantly more closely related to simian immunodeficiency viruses infecting sooty mangabeys and rhesus macaques (SIVSM/SIVMAC) than to any virus of human derivation. This subject also harboured multiply defective viral genotypes that resulted from hypermutation of G to A bases. Our results indicate that HIV-2, SIVSM and SIVMAC comprise a single, highly diverse group of lentiviruses which cannot be separated into distinct phylogenetic lineages according to species of origin.  相似文献   
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The HLA-D region of the human major histocompatibility complex (MHC) has been shown to be homologous to the murine I region in terms of both structure and function. Both regions encode class II MHC molecules which restrict T-lymphocyte interactions with antigen-presenting cells. We have recently described the MHC restriction and antigen specificities of human T-lymphocyte clones directed at strain A influenza virus. The majority of T-lymphocyte clones recognized antigen in the context of cell surface interaction products encoded by HLA-D/DR genes. However, a few clones recognized antigen presented by cells histoincompatible for D/DR antigens. We report here that some of these clones recognized viral antigens in association with antigens encoded by genes identical with or closely linked to the recently described secondary B-cell (SB) locus of the MHC. This is the first report that SB-restricted antigen recognition may form an integral part of normal, human immune responses.  相似文献   
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