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Towards a degradation-based mechanism for adaptive overload control

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Science china(Information Sciences) 2012年第12期55卷 2708-2722页

作者： WANG ZiYou 1,2,ZHOU MingHui 1,2 & MEI Hong 1,2 1 software Institute,School of Electronics Engineering and Computer Science,Peking University,beijing 100871,china 2.key laboratory of high confidence software technologies(Peking University),ministry of education,beijing 100871,china software Institute School of Electronics Engineering and Computer Science Peking University Beijing China ministry of education Key Laboratory of High Confidence Software Technologies (Peking University) Beijing China

Uncontrolled overload is one of the major causes of the system's decline in reliability and performance for web *** also harms the construction of trustworthy *** paper presents a degradationbased mechanism to adaptively control overload in complex,dynamic web *** our mechanism,the bottlenecks in the application's performance are determined by internally monitoring the performance and resource utilization state of the application,which is decomposed into a set of *** locating the bottlenecks,two decision algorithms are proposed to dynamically and adaptively generate proper degradation plans without *** degrading the service which consumes critical resources and has a low priority from the perspective of business logic,the application can keep providing key services even when overload *** implement a prototype and conduct a case study on a wiki *** also evaluate our approach and demonstrate its effectiveness in simulated overload *** handling overload,we make a breakthrough in building trustworthy software in an open,dynamic and rapidly changing environment.

关键词： overload service degradation resource monitoring performance management

A community-centric approach to automated service composition

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Science china(Information Sciences) 2010年第1期53卷 50-63页

作者： LIU XuanZhe1,2, HUANG Gang1,2 & MEI Hong1,2 1School of Electronics Engineering and Computer Science, Peking University, beijing 100871, china 2key laboratory of high confidence software technologies, ministry of education, Peking University, beijing 100871, china School of Electronics Engineering and Computer Science Peking University Beijing China key laboratory of high confidence software technologies Ministry of Education Peking University Beijing China

In the recent years, the web has kept growing rapidly and undergone tremendous changes towards a user-centric environment. With the proliferation of services available on the Internet, millions of users are able to voluntarily participate in and collaborate for their own interests and benefits by means of service composition. However, due to the ever increasing number of services, it then becomes a challenging issue to enable the users to rapidly select and compose the proper services. In this paper, we propose an approach which utilizes service communities for automated service composition. This paper makes three contributions. Firstly, we propose the service community architecture and identify two key components to facilitate service discovery and composition. Secondly, assisted by the service community, we provide two composition types to help users explore the space of potential composition opportunities without having to understand too many details of individual candidate services. Finally, we evaluate our approach by performance analysis and provide a web-based prototype that lowers the entry barrier for the users.

关键词： services computing service composition service community

A novel computing model of the maximum clique problem based on circular DNA

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Science china(Information Sciences) 2010年第7期53卷 1409-1416页

作者： YANG Jing, ZHANG Cheng, XU Jin*, LIU XiangRong & QIANG XiaoLi Institute of software, School of Electronics Engineering and Computer Science, key laboratory of high confidence software technologies, ministry of education, Peking University, beijing 100871, china Institute of software School of Electronics Engineering and Computer Science Key Laboratory of High Confidence Software Technologies Ministry of Education Peking University Beijing China

A novel DNA-based model is developed to calculate NP-complete problems, which is made of circular DNA molecules, streptavidin-coated magnetic beads and DNA circligase. To test the feasibility of the model, we apply it to compute a five-node maximum clique problem (MCP). During the computation, DNA molecule structures were transformed between linear DNA and circular DNA by streptavidin-coated magnetic beads and circligase, in order to search for the truth solutions. This greatly reduces the quantity of time and space consumed in calculation, and its time and space complexity both are O(n + m). Compared with the brute force method, using this algorithm searching process at most needs in n + 1 test tubes for an MCP with n vertices, while brute force method requires 2n test tubes. Furthermore, the constructed unenumerable initial solution space greatly improved the processing ability of the DNA computer. This novel model indicates that it may be a powerful DNA-based computer for solving some NP-complete problems.

关键词： DNA-based computing model circular DNA molecules NP-complete problem circligase streptavidin-coated magnetic beads

Online approach to feature interaction problems in middleware based system

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Science in china(Series F) 2008年第3期51卷 225-239页

作者： HUANG Gang1,2 LIU XuanZhe1,2 & MEI Hong1,2 1 key laboratory of high confidence software technologies, ministry of education, Peking University, beijing 1000871, china 2 School of Electronics Engineering and Computer Science, Peking University, beijing 100871, china key laboratory of high confidence software technologies Ministry of Education Peking University Beijing China School of Electronics Engineering and Computer Science Peking University Beijing China

As a popular infrastructure for distributed systems running on the Internet, middleware has to support much more diverse and complex interactions for coping with the drastically increasing demand on information technology and the extremely open and dynamic nature of the Internet. These supporting mechanisms facilitate the development, deployment, and integration of distributed systems, as well as increase the occasions for distributed systems to interact in an undesired way. The undesired interactions may cause serious problems, such as quality violation, function loss, and even system crash. In this paper, the problem is studied from the perspective of the feature interaction problem （FIP） in telecom, and an online approach to the detection and solution on runtime systems is proposed. Based on a classification of middleware enabled interactions, the existence of FIP in middleware based systems is illustrated by four real cases and a conceptual comparison between middleware based systems and telecom systems. After that, runtime software architecture is employed to facilitate the online detection and solution of FIP. The approach is demonstrated on J2EE （Java 2 Platform Enterprise Edition） and applied to detect and resolve all of the four real cases.

关键词： feature interaction middleware reflective software architecture

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A software architecture centric self-adaptation approach for Internetware

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Science in china(Series F) 2008年第6期51卷 722-742页

作者： MEI Hong1,2, HUANG Gang1,2, LAN Ling1,2 & LI JunGuo1,2 1 key laboratory of high confidence software technologies (Peking University), ministry of education, beijing 100871, china 2 School of Electronics Engineering and Computer Science, Peking University, beijing 100871, china key laboratory of high confidence software technologies (Peking University) Ministry of Education Beijing China School of Electronics Engineering and Computer Science Peking University Beijing China

Being one of the basic features of Internetware, self-adaptation means that the software system can monitor its runtime state and behavior and adjust them when necessary according to pre-defined policies. Focusing on the three fundamental issues of self-adaptation, including the scope, operability and trustworthiness, a software architecture （SA） centric approach for Internetware＇s self-adaptation is presented in this paper. All of the self-adaptive actions, i.e. monitoring, analyzing, planning and executing, are performed based on SA. In detail, runtime state and behavior of Internetware are represented and changed in the form of runtime soft- ware architecture. The knowledge for self-adaptation is captured, organized and reasoned in the form of SA so that automatic analysis and decision-making are achieved.

关键词： Internetware self-adaptation software architecture middleware

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Capability description and discovery of Internetware entity

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Science china(Information Sciences) 2010年第4期53卷 685-703页

作者： WANG PuWei1*, JIN Zhi2,3* & LIU HongYan4 1key laboratory of Data Engineering and Knowledge Engineering of the ministry of education, Renmin University of china, beijing 100872, china 2key laboratory of high confidence software technologies of the ministry of education, Peking University, beijing 100871, china 3Academy of Mathematics and System Sciences, Chinese Academy of Sciences, beijing 100190, china 4Department of Management Science and Engineering, Tsinghua University, beijing 100084, china key laboratory of Data Engineering and Knowledge Engineering of the ministry of education Renmin University of China Beijing China key laboratory of high confidence software technologies of the ministry of education Peking University Beijing China Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China Department of Management Science and Engineering Tsinghua University Beijing China

Internetware can be formed through aggregation of Internetware entities bottom-up to satisfy the user's requirements. In the process, capability description of Internetware entity plays an important role. This paper proposes a capability description of Internetware entity based on environment ontology. The environment ontology includes environment entities and possible interactions with the environment entities in a particular domain. Tree-like hierarchical state machines are also included in the ontology to describe domain life-cycle of the environment entities. On the basis of the ideas, the capability of Internetware entity is embodied by interacting with environment entities and the changes of the environment entities during the interactions. Finally, this paper describes the matchmaking between capability descriptions of Internetware entities to support the discovery of Internetware entity. An example of online education course is given to illustrate the ideas.

关键词： Internetware capability description domain environment ontology tree-like hierarchical state machine

Technical framework for Internetware: An architecture centric approach

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Science in china(Series F) 2008年第6期51卷 610-622页

作者： YANG FuQing1,2, Lü Jian3,4 & MEI Hong1,2 1 key laboratory of high confidence software technologies (Peking University), ministry of education, beijing 100871, china 2 School of Electronics Engineering and Computer Science, Peking University, beijing 100871, china 3 State key laboratory for Novel software Technology, Nanjing 210093, china 4 Department of Computer Science and Technology, Nanjing University, Nanjing 210093, china key laboratory of high confidence software technologies (Peking University) Ministry of Education Beijing China School of Electronics Engineering and Computer Science Peking University Beijing China State key laboratory for Novel software Technology Nanjing China Department of Computer Science and Technology Nanjing University Nanjing China

Being a new software paradigm evolved by the Internet, Internetware brings many challenges to the traditional software methods and techniques. Sponsored by the national basic research program （973）, researchers in china have developed an architecture centric technical framework for the definition, incarnation and engineering of Internetware. First of all, a software model for Internetware is defined for what to be, including that Internetware entities should be packaged as components, behaving as agents, interoperating as services, collaborating in a structured and on demand manner, etc. Secondly, a middleware for Internetware is designed and implemented for how to be, including that Internetware entities are incarnated by runtime containers, structured collaborations are enabled by runtime software architecture, Internetware can be managed in a reflective and autonomic manner, etc. Thirdly, an engineering methodology for Internetware is proposed for how to do, including the way to develop Internetware entities and their collaborations by transforming and refining a set of software architectures which cover all the phases of software lifecycle, the way to identify and organize the disordered software assets by domain modeling, etc.

关键词： Internetware component software architecture agent middleware

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The (⊿+2,2)-incidence coloring of outerplanar graphs

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Progress in Natural Science:Materials International 2008年第5期18卷 575-578页

作者： Shudong Wanga,b,c, Jin Xu a,b, Fangfang Mac, Chunxiang Xua,b a Institute of software, School of Electronic Engineering and Computer Science, Peking University, beijing 100871, china b key laboratory of high Con dence software technologies, ministry of education, beijing 100871, china c College of Information Science and Engineering, Shandong University of Science and Technology, Qingdao 266510, china Institute of software School of Electronic Engineering and Computer Science Peking University Beijing 100871 China key laboratory of high confidence software technologies Ministry of Education Beijing 100871 China College of Information Science and Engineering Shandong University of Science and Technology Qingdao 266510 China

An incidence coloring of graph G is a coloring of its incidences in which neighborly incidences are assigned di erent colors. In this paper, the incidence coloring of outerplanar graphs is discussed using the techniques of exchanging colors and the double inductions from the aspect of con guration property. Results show that there exists a (D + 2,2)-incidence coloring in every outerplanar graph, where D is the maximum degree of outerplanar graph.

关键词： Incidence coloring Incidence chromatic number Outerplanar graph

Molecular Computations of the Maximal Clique Problem Using DNA Self-assembly

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Molecular Computations of the Maximal Clique Problem Using D...