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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., peking university, beijing 100871, china 2.ey Laboratory of High Confidence Software Technologies, Ministry of Education, peking university, beijing 100871, china school of electronics {2. 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 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 ({2. {2.), 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 {2. 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

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 {2. {2. 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 2. 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

A study of constraints on the constitutive relationships of electromagnetic medium based on generally acknowledged truths

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science china(Physics,Mechanics & Astronomy) 2005年第5期48卷 541-548页

作者： GUO Huiping1, liu Xueguan1,2. YIN Hongcheng2. CHAO Zengming2.& huang Peikang{2.. school of {2. and Information engineering, Soochow university, Suzhou 2.502., china 2. National Electromagnetic Scattering Laboratory, beijing 100854, china school of electronics and Information {2. Soochow University Suzhou China National Electromagnetic Scattering Laboratory Beijing China

The study of constraints on the constitutive relationships of electromagnetic media is of great importance in the aspects of the medium characteristics analysis, the new article material synthesis and the medium parameters reconstruction, etc. According to the fact that the constitutive relationships should not conflict with the general physical laws, the constraints that the constitutive relationships of electromagnetic medium must satisfy have been summarized in this paper. These constraints include determinacy principle, objectivity principle, causality principle and permission principle. And the parameter constraints of the arbitrary linear homogenous time-invariant medium are obtained following the minimum energy consumption principle. This work provides a new way of ascertaining the constitutive relationships of the electromagnetic medium.

关键词： electromagnetic medium, medium parameter constraint, generally acknowledged truths, energy conservation principle, minimum energy consumption principle.

Low-modal-crosstalk doped-fiber amplifiers in few-mode-fiber-based systems

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Photonics Research 2024年第08期12卷 1768-1775页

作者： SHUAILUO huang LEI SHEN gang QIAO YUANPENG DING YUYANG GAO JIAN CUI BAOLONG ZHU SIYUAN {2. MINGQING ZUO JINGLONG ZHU LEI ZHANG JIE LUO YONGQI HE ZHANGYUAN CHEN JUHAO LI State Key Laboratory of Advanced Optical Communication Systems and Networks Peking University State Key Laboratory of Optical Fiber and Cable Manufacture Technology Yangtze Optical Fibre and Cable Joint Stock Limited Company school of computer and Communication {2. University of Science and Technology Beijing Department of Networks China Mobile Communications Group Co. Ltd. Department of Fundamental Network Technology China Mobile Research Institute Pengcheng Laboratory

Independent light propagation through one or multiple modes is commonly considered as a basic demand for mode manipulation in few-mode fiber（FMF）-or multimode fiber（MMF）-based optical systems such as transmission links, optical fiber lasers, or distributed optical fiber sensors. However, the insertion of doped-fiber amplifiers always kills the entire effort by inducing significant modal crosstalk. In this paper, we propose the design of doped-fiber amplifiers in FMF-based systems adopting identical multiple-ring-core（MRC） index profiles for both passive and doped fibers to achieve low modal crosstalk. We develop the direct-glass-transition（DGT） modified chemical vapor deposition（MCVD） processing for precise fabrication of few-mode erbium-doped fibers（FM-EDFs） with MRC profiles of both refractive index and erbium-ion doping distribution. Then, a few-mode erbium-doped-fiber amplifier（FM-EDFA） with a maximum gain of 2..08 dB and differential modal gain（DMG） of 2.3 dB is realized based on fabricated FM-EDF matched with a transmission FMF supporting four linearly polarized（LP） modes. With the insertion of the FM-EDFA, 60 + 60 km simultaneous LP01∕LP11∕LP2.∕LP02.ransmission without inter-modal multiple-input multiple-output digital signal processing（MIMO-DSP） is successfully demonstrated. The proposed design of low-modal-crosstalk doped-fiber amplifiers provides, to our knowledge, new insights into mode manipulation methods in various applications. ? 2.2. Chinese Laser Press

关键词： Chemical vapor deposition Erbium fibers Few mode fibers High power fiber lasers Multimode fibers Signal processing

Spatio-Temporal Adaptive Super-Resolution Reconstruction Model Based on Zemike Moment for Spatial Video Sequences

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china Communications 2012年第12期9卷 93-107页

作者： Liang Meiyu Du Junping JangMyung Lee liu Honggang Zhang Yun beijing Key Laboratory of Intelligent Telecommunication Software and Multimedia School of Computer Science Beijing University of Posts and Telecommunications Beijing 100876 P. R. China Department of electronics engineering Pusan Nation University Busan Korea

Video Super-Resolution （SR） reconstruction produces video sequences with High Resolution （HR） via the fusion of several Low-Resolution （LR） video frames. Traditional methods rely on the accurate estimation of subpixel motion, which constrains their applicability to video sequences with relatively simple motions such as global translation. We propose an efficient iterative spatio-temporal adaptive SR reconstruction model based on Zemike Moment （ZM）, which is effective for spatial video sequences with arbitrary motion. The model uses region correlation judgment and self-adaptive threshold strategies to improve the effect and time efficiency of the ZM-based SR method. This leads to better mining of non-local self-similarity and local structural regularity, and is robust to noise and rotation. An efficient iterative curvature-based interpolation scheme is introduced to obtain the initial HR estimation of each LR video frame. Experimental results both on spatial and standard video sequences demonstrate that the proposed method outperforms existing methods in terms of both subjective visual and objective quantitative evaluations, and greatly improves the time efficiency.

关键词： video super-resolution fuzzy registration scheme Zemike moment non-local self-similarity self-adaptive threshold

Towards module-based automatic partitioning of Java applications

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Frontiers of computer science 2012年第6期6卷 725-740页

作者： Ying ZHANG gang huang Wei ZHANG {2. liu Hong MEI Key Laboratory of High Confidence Software Technologies(peking university) Ministry of EducationBeijing 100871China school of electronics {2. and computer science Peking UniversityBeijing 100871China

When reengineering a monolithic application to be a distributed one, programmers always have to decide how many distributed parts the application should be partitioned, and write many codes related to where a part will be placed on network nodes and how these parts communicate with each other through the network. These codes usually have nothing to do with the business functions of the application, and they are laborious to write. In addition, as the distribution architecture of the application is finalized beforehand, it may not adapt well to the everchanging execution environment. In this paper, we propose DPartner, an automatic partitioning system, to help programmers create a distributed Java application without explicitly writing the distribution-related codes. Unlike the other partitioning systems, DPartner does not partition an application directly into the coarse-grained client and server. Instead, it first partitions the application into several modules where each module performs a relatively independent business function of the application. Then it makes these modules be distributable through automatic bytecode rewriting. These modules can distribute in different nodes and cooperate to work just as the original monolithic application. Such a module-based partitioning approach enables a relatively easy reshaping of the distribution architecture of an application, which facilitates the application adapt to the environmental changes without manual recoding or repartitioning with regard to distribution. This paper gives the detailed design of DPartner, and evaluates it using real-world applications. The evaluation results demonstrate the effectiveness and efficiency of DPartner.

关键词： application partitioning distributed computing,DPartner

地理大数据揭示中国主要城市建成环境物质存量的空间格局

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engineering 2024年第3期34卷 143-153页

作者： Zhou huang Yi Bao Ruichang Mao Han Wang Ganmin Yin Lin Wan Houji Qi Qiaoxuan Li Hongzhao Tang Qiance liu Linna Li Bailang Yu Qinghua Guo Yu liu Huadong Guo gang liu Institute of Remote Sensing and Geographical Information Systems School of Earth and Space SciencesPeking UniversityBeijing 100871China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China SDU Life Cycle engineering Department of Green TechnologyUniversity of Southern DenmarkOdense 5230Denmark Department of Construction Management School of Civil EngineeringTsinghua UniversityBeijing 100084China school of computer {2. China University of GeosciencesWuhan 430074China school of Geographical sciences East China Normal UniversityShanghai 200062China Land Satellite Remote Sensing Application Center Ministry of Natural ResourcesBeijing 100048China Institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Department of Geography California State UniversityLong BeachCA 90840USA Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China College of Urban and Environmental sciences Peking UniversityBeijing 100871China

The patterns of material accumulation in buildings and infrastructure accompanied by rapid urbanization offer an important,yet hitherto largely missing stock perspective for facilitating urban system engineering and informing urban resources,waste,and climate ***,our existing knowledge on the patterns of built environment stocks across and particularly within cities is limited,largely owing to the lack of sufficient high spatial resolution *** study leveraged multi-source big geodata,machine learning,and bottom-up stock accounting to characterize the built environment stocks of 50 cities in china at 500 m fine-grained *** per capita built environment stock of many cities({2. tonnes per capita on average)is close to that in western cities,despite considerable disparities across cities owing to their varying socioeconomic,geomorphology,and urban form *** is mainly owing to the construction boom and the building and infrastructure-driven economy of china in the past ***’s urban expansion tends to be more“vertical”(with high-rise buildings)than“horizontal”(with expanded road networks).It trades skylines for space,and reflects a concentration-dispersion-concentration pathway for spatialized built environment stocks development within cities in *** results shed light on future urbanization in developing cities,inform spatial planning,and support circular and low-carbon transitions in cities.

关键词： Urban system engineering Built environment stock Spatial pattern Urban sustainability Big geodata

DelayD roid: an instrumented approach to reducing tail-time energy of Android apps

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science china(Information sciences) 2017年第1期60卷 84-99页

作者： gang huang Huaqian CAI Maciej SWIECH Ying ZHANG {2. liu Peter DINDA school of electronics {2. and computer science Peking University Department of Electrical engineering and computer {2. Northwestern University

Mobile devices with 3G/4G networking often waste energy in the so-called "tail time" during which the radio is kept on even though no communication is occurring. Prior work has proposed policies to reduce this energy waste by batching network requests. However, this work is challenging to apply in practice due to a lack of mechanisms. In response, we have developed DelayD roid, a framework that allows a developer to add the needed policy to existing, unmodified Android applications(apps) with no human effort as well as no SDK/OS changes. This allows such prior work(as well as our own policies) to be readily deployed and evaluated. The DelayD roid compile-time uses static analysis and bytecode refactoring to identify method calls that send network requests and modify such calls to detour them to the DelayD roid run-time. The run-time then applies a policy to batch them, avoiding the tail time energy waste. DelayD roid also includes a cross-app communication mechanism that supports policies that optimize across multiple apps running together, and we propose a policy that does so. We evaluated the correctness and universality of the DelayD roid mechanisms on14 popular Android apps chosen from the Google App Store. To evaluate our proposed policy, we studied three DelayD roid-enabled apps(weather forecasting, email client, and news client) running together, finding that the DelayD roid mechanisms combined with our policy can reduce 3G/4G tail time energy waste by 36%.

关键词： refactor Android optimization energy network scheduling