We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms lim...We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.展开更多
Mining frequent patterns has been studied popularly in data mining area. However, little work has been done on mining patterns when the database has an influx of fresh data constantly. In these dynamic scenarios, effi...Mining frequent patterns has been studied popularly in data mining area. However, little work has been done on mining patterns when the database has an influx of fresh data constantly. In these dynamic scenarios, efficient maintenance of the discovered patterns is crucial. Most existing methods need to scan the entire database repeatedly, which is an obvious disadvantage. In this paper, an efficient incremental mining algorithm, Incremental-Mining (IM), is proposed for maintenance of the frequent patterns when incremental data come. Based on the frequent pattern tree (FP-tree) structure, IM gives a way to make the most of the things from the previous mining process, and requires scanning the original data once at most. Furthermore, IM can identify directly the differential set of frequent patterns, which may be more informative to users. Moreover, IM can deal with changing thresholds as well as changing data, thus provide a full maintenance scheme. IM has been implemented and the performance study shows it outperforms three other incremental algorithms: FUP, DB-tree and re-running frequent pattern growth (FP-growth). Keywords data mining - association rule mining - frequent pattern mining - incremental mining Supported by the National Basic Research 973 Program of China under Grant No.G1999032705.Xiu-Li Ma received the Ph.D. degree in computer science from Peking University in 2003. She is currently a postdoctoral researcher at National Lab on Machine Perception of Peking University. Her main research interests include data warehousing, data mining, intelligent online analysis, and sensor network.Yun-Hai Tong received the Ph.D. degree in computer software from Peking University in 2002. He is currently an assistant professor at School of Electronics Engineering and Computer Science of Peking University. His research interests include data warehousing, online analysis processing and data mining.Shi-Wei Tang received the B.S. degree in mathematics from Peking University in 1964. Now, he is a professor and Ph.D. supervisor at School of Electronics Engineering and Computer Science of Peking University. His research interests include DBMS, information integration, data warehousing. OLAP, and data mining, database technology in specific application fields. He is the vice chair of the Database Society of China Computer Federation.Dong-Qing Yang received the B.S. degree in mathematics from Peking University in 1969. Now, she is a professor and Ph.D supervisor at School of Electronics Engineering and Computer Science of Peking University. Her research interests include database design methodology, database system implementation techniques, data warehousing and data mining, information integration and sharing in Web environment. She is a member of academic committee of Database Society of China Computer Federation.展开更多
There exists a consensus that software architecture (SA) plays a central role in software development and also plays an important role in the lifecycle phases after software delivery. Particularly, SA can be used to r...There exists a consensus that software architecture (SA) plays a central role in software development and also plays an important role in the lifecycle phases after software delivery. Particularly, SA can be used to reduce the great difficulty and cost of software maintenance and evolution. In this paper, runtime software architecture (RSA) based on reflective middleware is proposed to support architecture-based software maintenance and evolution. In this approach, the actual states and behaviors of the runtime system can be observed and manipulated in a consistent and understandable way through its architectural view. Being an accurate, up-to-date, semantic and operable view of SA, RSA looks components and connectors as white-box entities to accurately and thoroughly describe the runtime system, extends traditional architecture description languages to formally describe itself and naturally inherit plentiful semantics in traditional views of SA, and utilizes reflective middleware to observe and manipulate the runtime system. In order to demonstrate the feasibility of this approach, a reflective J2EE application server, called PKUAS, is implemented to observe and manipulate the components, connectors and constraints in the runtime system. Finally, the performance evaluation proves that making RSA explicit and operable at runtime has little effect on the runtime system.展开更多
To solve the problems of the interleaving assumption and the single resource inPUNITY (Petri net and UNITY) and Petri net respectively, this paper proposes a set of mappingrules from PUNITY to UniNet. Based on these r...To solve the problems of the interleaving assumption and the single resource inPUNITY (Petri net and UNITY) and Petri net respectively, this paper proposes a set of mappingrules from PUNITY to UniNet. Based on these rules, problems of one field can be transformed toproblems of the other field and powerful tools of Petri net and UNITY can be used. The papergives a sketch of the mapping rules and applies the rules to an example. Meanwhile, the mappingrules can help computer to translate PUNITY to UniNet easily.展开更多
文摘We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.
文摘Mining frequent patterns has been studied popularly in data mining area. However, little work has been done on mining patterns when the database has an influx of fresh data constantly. In these dynamic scenarios, efficient maintenance of the discovered patterns is crucial. Most existing methods need to scan the entire database repeatedly, which is an obvious disadvantage. In this paper, an efficient incremental mining algorithm, Incremental-Mining (IM), is proposed for maintenance of the frequent patterns when incremental data come. Based on the frequent pattern tree (FP-tree) structure, IM gives a way to make the most of the things from the previous mining process, and requires scanning the original data once at most. Furthermore, IM can identify directly the differential set of frequent patterns, which may be more informative to users. Moreover, IM can deal with changing thresholds as well as changing data, thus provide a full maintenance scheme. IM has been implemented and the performance study shows it outperforms three other incremental algorithms: FUP, DB-tree and re-running frequent pattern growth (FP-growth). Keywords data mining - association rule mining - frequent pattern mining - incremental mining Supported by the National Basic Research 973 Program of China under Grant No.G1999032705.Xiu-Li Ma received the Ph.D. degree in computer science from Peking University in 2003. She is currently a postdoctoral researcher at National Lab on Machine Perception of Peking University. Her main research interests include data warehousing, data mining, intelligent online analysis, and sensor network.Yun-Hai Tong received the Ph.D. degree in computer software from Peking University in 2002. He is currently an assistant professor at School of Electronics Engineering and Computer Science of Peking University. His research interests include data warehousing, online analysis processing and data mining.Shi-Wei Tang received the B.S. degree in mathematics from Peking University in 1964. Now, he is a professor and Ph.D. supervisor at School of Electronics Engineering and Computer Science of Peking University. His research interests include DBMS, information integration, data warehousing. OLAP, and data mining, database technology in specific application fields. He is the vice chair of the Database Society of China Computer Federation.Dong-Qing Yang received the B.S. degree in mathematics from Peking University in 1969. Now, she is a professor and Ph.D supervisor at School of Electronics Engineering and Computer Science of Peking University. Her research interests include database design methodology, database system implementation techniques, data warehousing and data mining, information integration and sharing in Web environment. She is a member of academic committee of Database Society of China Computer Federation.
文摘There exists a consensus that software architecture (SA) plays a central role in software development and also plays an important role in the lifecycle phases after software delivery. Particularly, SA can be used to reduce the great difficulty and cost of software maintenance and evolution. In this paper, runtime software architecture (RSA) based on reflective middleware is proposed to support architecture-based software maintenance and evolution. In this approach, the actual states and behaviors of the runtime system can be observed and manipulated in a consistent and understandable way through its architectural view. Being an accurate, up-to-date, semantic and operable view of SA, RSA looks components and connectors as white-box entities to accurately and thoroughly describe the runtime system, extends traditional architecture description languages to formally describe itself and naturally inherit plentiful semantics in traditional views of SA, and utilizes reflective middleware to observe and manipulate the runtime system. In order to demonstrate the feasibility of this approach, a reflective J2EE application server, called PKUAS, is implemented to observe and manipulate the components, connectors and constraints in the runtime system. Finally, the performance evaluation proves that making RSA explicit and operable at runtime has little effect on the runtime system.
文摘To solve the problems of the interleaving assumption and the single resource inPUNITY (Petri net and UNITY) and Petri net respectively, this paper proposes a set of mappingrules from PUNITY to UniNet. Based on these rules, problems of one field can be transformed toproblems of the other field and powerful tools of Petri net and UNITY can be used. The papergives a sketch of the mapping rules and applies the rules to an example. Meanwhile, the mappingrules can help computer to translate PUNITY to UniNet easily.
