检索结果-南通市图书馆

Technical framework for Internetware: An architecture centric approach

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 school of electronics engineering and computer science Peking University State Key Laboratory for Novel Software Technology Department of computer Scien

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

A software architecture centric self-adaptation approach for Internetware

在线全文

学校读者我要写书评

暂无评论

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 school of electronics engineering and computer science Peking University

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

Online approach to feature interaction problems in middleware based system

在线全文

学校读者我要写书评

暂无评论

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 school of electronics engineering and computer science Peking University

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

Up-conversion emissions of Er^(3+)-Yb^(3+) codoped Al_2O_3 nanoparticles by the arc discharge synthesis method

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1043-1046页

作者： DONG Bin1, CAO BaoSheng1, FENG ZhiQing1, WANG XingJun2, LI ChengRen3 & HUA RuiNian4 1 school of science, Dalian Nationalities university, Dalian 116600, china 2 school of electronics engineering and computer science, peking university, beijing 100871, china 3 College of Physics and Electronic Technology, Liaoning Normal university, Dalian 116029, china 4 College of Life science, Dalian Nationalities university, Dalian 116600, china school of science Dalian Nationalities University Dalian China school of electronics engineering and computer science Peking University Beijing China College of Physics and Electronic Technology Liaoning Normal University Dalian China College of Life science Dalian Nationalities University Dalian China

The Er3+-Yb3+ codoped Al2O3 nanoparticles with an average particle size of about 50 nm have been synthesized by an arc discharge synthesis method. The green and red up-conversion emissions centered at about 526, 547 and 677 nm, corresponding respectively to the 2H11/2→4I15/2, 4S3/2→4I15/2 and 4 F9/2→4I15/2 transitions of Er3+, were detected by a 978-nm semiconductor laser diode excitation. The Annealing has evident effect on the up-conversion emissions of the samples: The red up-conversion emission is noticeable before annealing; however, the green up-conversion emission becomes predominant after annealing. The mixture of (Er,Yb)3Al5O12 and α-(Al,Er,Yb)2O3 phases is more favorable for green up-conversion emissions due to an enhancement of the ESA (I) of 4I11/2+a photon→4F7/2 and ET (III) of 2F5/2(Yb3+)+4I11/2(Er3+)→2F7/2(Yb3+)+4F7/2(Er3+) processes. The two-photon absorption up-conversion process is involved in the green and red up-conversion emissions. The results have proved that arc discharge synthesis is a new promising preparation technology for optical materials.

关键词： up-conversion Er3+-Yb3+ codoped Al2O3 arc discharge synthesis

在线全文

学校读者我要写书评

暂无评论

基于迭代技术的调零方法研究

通信对抗 2007年第4期26卷 25-28页

作者：乔丹尚勇梁斌田敏北京大学信息科学技术学院北京100871 石河子大学信息科学技术学院新疆石河子832003

卫星智能天线的一项核心技术是波束成形。传统调零算法是波束成形算法的一种，它对所有干扰置零，需要求导向矢量矩阵的逆矩阵，运算比较复杂。逐个调零算法和调零算法的目的基本一致，也是对干扰置零，它不必求矩阵的逆，但是对干扰的... 详细信息

卫星智能天线的一项核心技术是波束成形。传统调零算法是波束成形算法的一种，它对所有干扰置零，需要求导向矢量矩阵的逆矩阵，运算比较复杂。逐个调零算法和调零算法的目的基本一致，也是对干扰置零，它不必求矩阵的逆，但是对干扰的置零能力有限。文章提出基于迭代的逐个调零算法，是对逐个调零算法的改进，在不增加太多计算量的情形下，提高了干扰抑制能力，最后给出了仿真结果，验证了改进算法的可行性和有效性。

关键词：波束成形迭代技术卫星智能天线调零算法

Improved innovation-based adaptive Kalman filter for dual-frequency navigation using carrier phase

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第12期53卷 2653-2663页

作者： LU ChenXi,TAN YunHua ,ZHU BoCheng & ZHOU LeZhu school of electronics engineering and computer science,peking university,beijing 100871,china school of electronics engineering and computer science Peking University

A new adaptive Kalman filtering algorithm for dual-frequency navigation using carrier phase is *** algorithm gives consideration to both robustness and sensitivity by combining the two main approaches of adaptive Kalman filtering based on innovation-based adaptive estimation(IAE) and fading *** to the navigation using carrier phase measurements typically,this algorithm can balance the weights of observations and predicted states *** to both practical static data and kinetic simulations are presented to demonstrate the validity and efficiency of the algorithm.

关键词： navigation adaptive Kalman filter carrier phase

A malware detection model based on a negative selection algorithm with penalty factor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第12期53卷 2461-2471页

作者： ZHANG PengTao 1,2 , WANG Wei 1,2 & TAN Ying 1,2 1 Department of Machine Intelligence, school of electronics engineering and computer science, peking university, beijing 100871, china 2 Key Laboratory of Machine Perception, Ministry of Education, peking university, beijing 100871, china Department of Machine Intelligence School of Electronics Engineering and Computer Science Peking University Key Laboratory of Machine Perception Ministry of Education Peking University

A malware detection model based on a negative selection algorithm with penalty factor (NSAPF) is proposed in this paper. This model extracts a malware instruction library (MIL), containing instructions that tend to appear in malware, through deep instruction analysis with respect to instruction frequency and file frequency. From the MIL, the proposed model creates a malware candidate signature library (MCSL) and a benign program malware-like signature library (BPMSL) by splitting programs orderly into various short bit strings. Depending on whether a signature matches "self", the NSAPF further divides the MCSL into two malware detection signature libraries (MDSL1 and MDSL2), and uses these as a two-dimensional reference for detecting suspicious programs. The model classifies suspicious programs as malware and benign programs by matching values of the suspicious programs with MDSL1 and MDSL2. Introduction of a penalty factor C in the negative selection algorithm enables this model to overcome the drawback of traditional negative selection algorithms in defining the harmfulness of "self" and "nonself", and focus on the harmfulness of the code, thus greatly improving the effectiveness of the model and also enabling the model to satisfy the different requirements of users in terms of true positive and false positive rates. Experimental results confirm that the proposed model achieves a better true positive rate on completely unknown malware and a better generalization ability while keeping a low false positive rate. The model can balance and adjust the true positive and false positive rates by adjusting the penalty factor C to achieve better performance.

关键词： penalty factor negative selection algorithm signature extraction artificial immune system mal- ware detection

Singularity detection of the rabbit electrocardiogram:An evolutionary spectral method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2009年第10期19卷 1317-1326页

作者： Xinyuan Liua,Dingwu He a,Liuqing Pei b,Suming Zhanga a school of electronics engineering and computer science,peking university,beijing 100871,china b College of Information science and engineering,beijing Normal university,beijing 100875,china school of electronics engineering and computer science Peking University Beijing 100871 China College of Information science and engineering Beijing Normal University Beijing 100875 China

The time-frequency characteristics of the spectral density of non-stationary signals(NSS) in the neighborhood of an instant time point can be determined using the evolutionary spectral *** experimental rabbit model involving ligation of the left anterior descending coronary artery to simulate the physiology of early phase myocardial ischemia(EPMI) has been previously ***,EPMI derived from left coronary artery stenosis is the main symptom of coronary heart diseases including acute myocardial ***,we propose a new algorithm for estimating the evolutionary spectral density functions,which is an effective approach to determine the instantaneous frequency spectra(IFS) of NSS under the uncertainty principle in the time-frequency *** localization singularity information in the data recorded from a living system could be detected by means of the ***(ECG) data recorded from experimental rabbits were analyzed with the new *** showed that the Q’s value of the evolutionary spectral quality number of the QRS-complex data was the characteristic parameter of ECG,and there was a matched connection between the time-frequency characteristics of QRS-complex data and the myocardial ischemia symptoms of the *** results provide valuable information regarding features of the EPMI for use in clinical diagnoses.

关键词： Non-stationary signals Electrocardiogram(ECG) Evolutionary spectrum Instantaneous frequency spectrum(IFS) Myocardial ischemia

Towards a degradation-based mechanism for adaptive overload control

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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