As service oriented architecture （SOA） matures, service consumption demand leads to an urgent requirement for service discovery. Unlike Web documents, services are intended to be executed to achieve objectives and/o...As service oriented architecture （SOA） matures, service consumption demand leads to an urgent requirement for service discovery. Unlike Web documents, services are intended to be executed to achieve objectives and/or desired goals of users. This leads to the notion that service discovery should take the ＂usage context＂ of service into account as well as service content （descriptions） which have been well explored. In this paper, we introduce the concept of service context which is used to represent service usage. In query processing, both service content and service context are ex- amined to identify services. We propose to represent ser- vice context by a weighted bipartite graph model. Based on the bipartite graph model, we reduce the gap between query space and service space by query expansion to improve re- call. We also design an iteration algorithm for result ranking by considering service contextsefulness as well as contentrelevance to improve precision. Finally, we develop a service search engine implementing this mechanism, and conduct some experiments to verify our idea.展开更多
Due to inherent heterogeneity, multi-domain characteristic and highly dynamic nature, authorization is a critical concern in grid computing. This paper proposes a general authorization and access control architecture,...Due to inherent heterogeneity, multi-domain characteristic and highly dynamic nature, authorization is a critical concern in grid computing. This paper proposes a general authorization and access control architecture, grid usage control （GUCON）, for grid computing. It＇s based on the next generation access control mechanism usage control （UCON） model. The GUCON Framework dynamic grants and adapts permission to the subject based on a set of contextual information collected from the system environments; while retaining the authorization by evaluating access requests based on subject attributes, object attributes and requests. In general, GUCON model provides very flexible approaches to adapt the dynamically security request. GUCON model is being implemented in our experiment prototype.展开更多
The relationship between the codon usage bias, gene expression level and the AUG context(from -20 to +6 positions relative to the initiator AUG codon) was examined in 541unigene sequences of rice. A significant correl...The relationship between the codon usage bias, gene expression level and the AUG context(from -20 to +6 positions relative to the initiator AUG codon) was examined in 541unigene sequences of rice. A significant correlation for CAI values (codon adaptationindex) was observed at five nucleotide positions (-19, -18, -9, -4, +5), eight (-19, -18,-14, -9, -6, -4, -1, +5) for CPP (codon preference parameter), and seven (-18, -16, -15,-9, -7, -1, +6) for mRNA abundance in the flanking sequence of the initiator AUG codonrespectively, but a significantly positive correlation for both CAI and CPP at twopositions (-4 and +5), indicating that both those positions are evolutionally under thenatural selection constraint at the translational level. By site-directed mutagenesis atseven specific positions (-18, -16, -15, -9, -7, -1 and +6) for allergenic protein thathad the highest mRNA abundance in this study, its expression level decreased dramatically63.3 and 72.5% respectively, indicating the importance of those 7 positions for geneexpression. A highly positive correlation (r=0.625, P<0.01) between AUGCAI and GCcontent in the flanking sequence of the initiator AUG codon showed a more effectivehigher GC content on translation initiation efficiency. The strong preference for G orC at those 8 positions (-6, -5, -3, -2, -1, +4, +5 and +6) in the AUG context suggestedthat an important factor in modulation of the translation efficiency, as well assynonymous codon usage bias, particularly in highly expressed genes.展开更多
文摘As service oriented architecture （SOA） matures, service consumption demand leads to an urgent requirement for service discovery. Unlike Web documents, services are intended to be executed to achieve objectives and/or desired goals of users. This leads to the notion that service discovery should take the ＂usage context＂ of service into account as well as service content （descriptions） which have been well explored. In this paper, we introduce the concept of service context which is used to represent service usage. In query processing, both service content and service context are ex- amined to identify services. We propose to represent ser- vice context by a weighted bipartite graph model. Based on the bipartite graph model, we reduce the gap between query space and service space by query expansion to improve re- call. We also design an iteration algorithm for result ranking by considering service contextsefulness as well as contentrelevance to improve precision. Finally, we develop a service search engine implementing this mechanism, and conduct some experiments to verify our idea.
基金Supported by the National Natural Science Foun-dation of China (60403027)
文摘Due to inherent heterogeneity, multi-domain characteristic and highly dynamic nature, authorization is a critical concern in grid computing. This paper proposes a general authorization and access control architecture, grid usage control （GUCON）, for grid computing. It＇s based on the next generation access control mechanism usage control （UCON） model. The GUCON Framework dynamic grants and adapts permission to the subject based on a set of contextual information collected from the system environments; while retaining the authorization by evaluating access requests based on subject attributes, object attributes and requests. In general, GUCON model provides very flexible approaches to adapt the dynamically security request. GUCON model is being implemented in our experiment prototype.
基金This work was supported by the National Natural Science Foundation of China(39870421)the Key Research Project of Zhejiang Province,China(2003C22007).
文摘The relationship between the codon usage bias, gene expression level and the AUG context(from -20 to +6 positions relative to the initiator AUG codon) was examined in 541unigene sequences of rice. A significant correlation for CAI values (codon adaptationindex) was observed at five nucleotide positions (-19, -18, -9, -4, +5), eight (-19, -18,-14, -9, -6, -4, -1, +5) for CPP (codon preference parameter), and seven (-18, -16, -15,-9, -7, -1, +6) for mRNA abundance in the flanking sequence of the initiator AUG codonrespectively, but a significantly positive correlation for both CAI and CPP at twopositions (-4 and +5), indicating that both those positions are evolutionally under thenatural selection constraint at the translational level. By site-directed mutagenesis atseven specific positions (-18, -16, -15, -9, -7, -1 and +6) for allergenic protein thathad the highest mRNA abundance in this study, its expression level decreased dramatically63.3 and 72.5% respectively, indicating the importance of those 7 positions for geneexpression. A highly positive correlation (r=0.625, P<0.01) between AUGCAI and GCcontent in the flanking sequence of the initiator AUG codon showed a more effectivehigher GC content on translation initiation efficiency. The strong preference for G orC at those 8 positions (-6, -5, -3, -2, -1, +4, +5 and +6) in the AUG context suggestedthat an important factor in modulation of the translation efficiency, as well assynonymous codon usage bias, particularly in highly expressed genes.
