The model of transfer line and an adaptive congestion-oriented routing algorithm

A transfer line can be modeled as a linear system on maximal algebra. The model is also suitable to ATM and other rate-based communication systems. In respect to the rate-based speciality, a periodical input is considered as the system' s controller. Then some results in utilization, stability and congestion have been obtained. By use of them, we design an algorithm which integrates routing, resource allocation and flow control into a closed-loop architecture. It is adaptive and solves the prob-lem of congestion and uneven resource utilization. It also succeeds in controlling delay and delay jitter.     

Learning by doing： Software project management course education

One of the key factors influencing project success or failure is project management. Unfortunately, effective management of software projects is not in practice. To meet the requirements of enterprises, majors in computer in more and more universities offer software project management course. However, as Reif and Marti put it, ＂successful software project management, like programming, is not a skill that students will master from a single course of instruction＂. In this work, we present a teaching mode based on project-driven for software project management course, and describe it from the aspects of training objectives, teaching implementation, the student＇s job, and assessment mechanism, and finally provide a summary and analysis of the characteristics of this teaching mode as well as the effect of the curriculum practice.     

On-Line Predicting Behaviors of Jobs in Dynamic Load Balancing

A key issue of dynamic load balancing in a lossely coupled distributed system is selecting appropriate jobs to transfer.In this paper,a job selection policy based on on-line predicting behaviors of jobs is proposed.Tracing is used at the beginning of execution of a job to predict the approximate execution time and resource requirements of th job so as to make a correct decision about whether transferring the job is worthwhil.A dynamic load balancer using the job selection policy has been implemented.Experimental measurement results show that the policy proposed is able to improve mean response time of jobs and resource utilization of systems substantially.     

Analysis of the virtual enterprise partner selection based on multi-agent system

Today, virtual enterprise is regarded as the most competitive management model of enterprises that faces the resource of the globe. This paper proposed an instructor of remote manufacturing system supporting dynamic alliance for virtual enterprises with the multi-agent technology to solve the problem of partner enterprise selection. Grounding on the virtual enterprise＇s cooperation framework, a model was given and in which we analyze the collaboration relation among different agents. The negotiation model will reduce the time and improve the efficiency of negotiation, so the appropriate partner can be selected in a short time.     

安全操作系统授权撤销机制的研究

Revoking operation is a very important component of access control. The lack of effective revoking operation impinges on supporting dynamic security policies in secure operation system. Analyzing authorization system,this paper presents a revoke policy which supports cascade and noncascade revocation. The policy adopts Hash authorization list and critical-based callback function to implement revocation of point to point and point to plane. Our experiments in security kernel show the mechanism is feasible ,which provides the basis of further researching dynamic security policies in secure operation system.     

A cross-layer fault tolerance management module for wireless sensor networks

It is a well-established fact that wireless sensor networks (WSNs) are very power constraint networks, but besides this, they are inherently more fault-prone than any other type of wireless network and their protocol design is very application specific. Major reasons for the faults are the unpredictable wireless communication channel, battery depletion, as well as fragility and mobility of the nodes. Furthermore, as traditional protocol design methods have proved inadequate, the cross-layer design (CLD) approach, which allows for interactions between different layers, providing more flexible and energy-efficient functionality, has emerged as a viable solution for WSNs. In this study we define a fault tolerance management module suitable to the requirements, limitations, and specifics of WSNs, encompassing methods for fault detection, fault prevention, fault management, and recovery. The suggested solution is in line with the CLD approach, which is an important factor in increasing the network performance. Through simulations the functionality of the network is evaluated, based on packet loss, delay, and energy consumption, and is compared with a similar solution not including fault management. The results achieved support the idea that the introduction of a unified approach to fault management improves the network performance as a whole.     

A novel approach to equipment health management based on auto-regressive hidden semi-Markov model （AR-HSMM）

As a new maintenance method, CBM （condition based maintenance） is becoming more and more important for the health management of complicated and costly equipment. A prerequisite to widespread deployment of CBM technology and prac- tice in industry is effective diagnostics and prognostics. Recently, a pattern recog- nition technique called HMM （hidden Markov model） was widely used in many fields. However, due to some unrealistic assumptions, diagnositic results from HMM were not so good, and it was difficult to use HMM directly for prognosis. By relaxing the unrealistic assumptions in HMM, this paper presents a novel approach to equip- ment health management based on auto-regressive hidden semi-Markov model （AR-HSMM）. Compared with HMM, AR-HSMM has three advantages： 1） It allows explicitly modeling the time duration of the hidden states and therefore is capable of prognosis. 2） It can relax observations＇ independence assumption by accom- modating a link between consecutive observations. 3） It does not follow the unre- alistic Markov chain＇s memoryless assumption and therefore provides more pow- erful modeling and analysis capability for real problems. To facilitate the computa- tion in the proposed AR-HSMM-based diagnostics and prognostics, new forward- backward variables are defined and a modified forward-backward algorithm is de- veloped. The evaluation of the proposed methodology was carried out through a real world application case study： health diagnosis and prognosis of hydraulic pumps in Caterpillar Inc. The testing results show that the proposed new approach based on AR-HSMM is effective and can provide useful support for the decision- making in equipment health management.     

Globus Toolkit Version 4: Software for Service-Oriented Systems

The Globus Toolkit （GT） has been developed since the late 1990s to support the development of serviceoriented distributed computing applications and infrastructures. Core GT components address, within a common framework, fundamental issues relating to security, resource access, resource management, data movement, resource discovery, and so forth. These components enable a broader ＂Globus ecosystem＂ of tools and components that build on, or interoperate with, GT functionality to provide a wide range of useful application-level functions. These tools have in turn been used to develop a wide range of both ＂Grid＂ infrastructures and distributed applications. I summarize here the principal characteristics of the recent Web Services-based GT4 release, which provides significant improvements over previous releases in terms of robustness, performance,, usability, documentation, standards compliance, and functionality. I also introduce the new ＂dev.globus＂ community development process, which allows a larger community to contribute to the development of Globus software.     

Pearson＇s Correlation Coefficient： A More Realistic Threshold for Applications on Autonomous Robotics

Many applications for control of autonomous platform are being developed and one important aspect is the excess of information, frequently redundant, that imposes a great computational cost in data processing. Taking into account the temporal coherence between consecutive frames, the PCC （Pearson＇s Correlation Coefficient） was proposed and applied as： discarding criteria methodology, dynamic power management solution, environment observer method which selects automatically only the regions-of-interest; and taking place in the obstacle avoidance context, as a method for collision risk estimation for vehicles in dynamic and unknown environments. Even if the PCC is a great tool to help the autonomous or semi-autonomous navigation, distortions in the imaging system, pixel noise, slight variations in the object＇s position relative to the camera, and other factors produce a false PCC threshold. Whereas there are homogeneous regions in the image, in order to obtain a more realistic Pearson＇s correlation, we propose to use some prior known environment information.     

Trustworthiness of Internet-based software

Recent years see an increasing concern over the trustworthiness of Inter- net-based software. By analyzing the trustworthiness of Internet-based software and the nature of the Internet applications, we point out that, on the one hand, due to the open- ness and dynamic nature of the Internet, the identity trustworthiness and the capability trustworthiness of the software are facing serious challenges; on the other hand, in order to ensure the trustworthiness of the whole system, emerging computing paradigms based on the collaboration of autonomous software need some impacts on the behavior of the software. Here we put forward a conceptual model for the trustworthiness of Inter- net-based software, and propose a trustworthy assurance framework for Internet-based virtual computing environment (iVCE). This framework deals with the trustworthy proper- ties of software on identity, capability and behavior in a combinated way. The authorization management in inter-domain computing environment, assurance on high availability of service and incentive mechanism for autonomic collaboration are taken as three core mechanisms of iVCE trustworthy assurance.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate