To meet the requirements of modeling the new modality of peer-to-peer（P2P）network applications which have been rapidly developing in the Internet recently, a formal description method for modeling multiparty concurr...To meet the requirements of modeling the new modality of peer-to-peer（P2P）network applications which have been rapidly developing in the Internet recently, a formal description method for modeling multiparty concurrent network interactions is studied. The main characteristics and the classifications of P2P systems are discussed. Considering the requirements of P2P application modeling and referring to the component-based modeling thought, a description method based on communicating sequential processes （CSP）is proposed for the P2P network models. By using a CSP process group, this method can describe the dynamic interactive relationship which focuses on multiparty concurrent interaction of P2P systems more advantageously and accurately. The application of nondeterministic semantemes of CSP in describing the interactive relationship of P2P networks is discussed. The advantages and description abilities of the proposed method are demonstrated through the modeling of a new P2P media-on-demand system.展开更多
Introduction of species evolutionary sequence into the quantitative biostratigraphy is a significant work, either for studying biologic evolution or for making stratigraphic correlation and reconstructing geologic his...Introduction of species evolutionary sequence into the quantitative biostratigraphy is a significant work, either for studying biologic evolution or for making stratigraphic correlation and reconstructing geologic history. The quantitative biostratigraphy is to determine biostratigraphic event sequences by using probabilistic analysis. The evolutionary sequence systematics can efficiently ascertain species evolutionary sequences. Two methods have been proposed to determine the sequence of species-disappearance events: (1) species extinction events can be closed by last occurrence events using quantitative biostratigraphic analysis; (2) the duration of a species may be approximately replaced by the duration of its parent species. To combine these two methods for determining the sequence of species disappearance is the best way up to now. A consulting standard sequence that consists of the speciation sequence of Permian waagenophylloid corals and the biostratigraphic event sequence of other important fossils in Permian is used as an example. The group spearman rank-correlation test is used to test the consulting standard sequence by comparing four types of calculations and two kinds of sequences and to find abnormal events. Based on the found abnormal events in the test, the consulting standard sequence is revised to deal with different conditions. Sequences of speciation and species-disappearance, and species duration are determined. Application of species evolutionary sequence to quantitative biostratigraphy can largely improve the quality of biostratigraphic event sequence. In stratigraphic correlation, furthermore, event sequences have higher precision than range biozones.展开更多
基金The National Basic Research Program of China (973 Program)(No.2003CB314801,2009CB320501)
文摘To meet the requirements of modeling the new modality of peer-to-peer（P2P）network applications which have been rapidly developing in the Internet recently, a formal description method for modeling multiparty concurrent network interactions is studied. The main characteristics and the classifications of P2P systems are discussed. Considering the requirements of P2P application modeling and referring to the component-based modeling thought, a description method based on communicating sequential processes （CSP）is proposed for the P2P network models. By using a CSP process group, this method can describe the dynamic interactive relationship which focuses on multiparty concurrent interaction of P2P systems more advantageously and accurately. The application of nondeterministic semantemes of CSP in describing the interactive relationship of P2P networks is discussed. The advantages and description abilities of the proposed method are demonstrated through the modeling of a new P2P media-on-demand system.
基金by the National Natural Science Foundation of China (Grant No. 49872014) and the Doctoral Program of Higher Education of China (Grant No. 97014001).
文摘Introduction of species evolutionary sequence into the quantitative biostratigraphy is a significant work, either for studying biologic evolution or for making stratigraphic correlation and reconstructing geologic history. The quantitative biostratigraphy is to determine biostratigraphic event sequences by using probabilistic analysis. The evolutionary sequence systematics can efficiently ascertain species evolutionary sequences. Two methods have been proposed to determine the sequence of species-disappearance events: (1) species extinction events can be closed by last occurrence events using quantitative biostratigraphic analysis; (2) the duration of a species may be approximately replaced by the duration of its parent species. To combine these two methods for determining the sequence of species disappearance is the best way up to now. A consulting standard sequence that consists of the speciation sequence of Permian waagenophylloid corals and the biostratigraphic event sequence of other important fossils in Permian is used as an example. The group spearman rank-correlation test is used to test the consulting standard sequence by comparing four types of calculations and two kinds of sequences and to find abnormal events. Based on the found abnormal events in the test, the consulting standard sequence is revised to deal with different conditions. Sequences of speciation and species-disappearance, and species duration are determined. Application of species evolutionary sequence to quantitative biostratigraphy can largely improve the quality of biostratigraphic event sequence. In stratigraphic correlation, furthermore, event sequences have higher precision than range biozones.
