电子商品交易系统中间件的设计及应用

针对分布式网络环境中电子商品交易的特点，采用TCP／IP机制、消息队列、身份论证，数字签名及加密等技术，研究实现了一种适合于实时商品交易系统的中间件，较好地满足了电子交易的实时性、可靠性、安全性等性能要求。本文讨论了该中间件的结构模型、工作机制及应用层协议。     

交易中间件的基本实现原理

介绍了交易中间件的参考模型，以及遵循DTP模型对交易中间件的功能定位和接口定义，对交易中间件的交易完整性保证机制和流量控制机制作了说明，并总结了中间件的处理效率。     

基于三层结构交易中间件系统设计

介绍了三层结构交易中间件体系结构的系统实现模型，论述了在该模型下通信层和交易调度层的设计思路和实现方法，给出了交易调度层动态优先级算法的实现思路。     

DTP中交易完整性的研究与实现

本文通过DTP模型介绍了交易中间件在分布式交易处理系统中的工作机制.讨论了如何在分布式事务处理中实现交易的完整性,分析了几种交易处理方式以及完整性管理策略,提出了一种通用中间件模型,支持两阶段提交协议、快速XA、和锁与自动确认冲正机制相结合的交易处理方式,在控制交易风险的基础上,提高了系统的整体效率.     

交易中间件的研究与实现

文章设计了一个交易中间件模型，该模型主要由通信进程、交易进程和服务进程组成，同时介绍了应用层接口和数据库接口，重点描述了交易处理方式及完整性保护机制。为了有效地控制交易风险，提出了一种锁与自动确认／冲正相结合的处理方式。     

基于消息分拣和双级请求队列的交易引警模型

交易引擎的结构模型直接影响到交易引擎的引工作机制、计算能力和性能指标。通过分析多模式交易的交易机制，引入虚拟杂多处理机的概念，提出了虚拟混杂多处理机计算环境中基于消息分拣和双级请求队列的多模式交易引擎的软件结构模型。讨论了该模型中虚拟多处理机和分拣器的工作机制以及基于该模型的交易引擎的通信机制。     

基于消息分拣和双级请求队列的交易引擎模型

交易引擎的结构模型直接影响到交易引擎的工作机制、计算能力和性能指标。通过分析多模式交易的交易机制 ,引入虚拟混杂多处理机的概念 ,提出了虚拟混杂多处理机计算环境中基于消息分拣和双级请求队列的多模式交易引擎的软件结构模型。讨论了该模型中虚拟多处理机和分拣器的工作机制以及基于该模型的交易引擎的通信机制。     

商品交易系统中间件的设计与实现

论文设计了一个中间件,该中间件由通信进程、交易进程、认证和授权服务进程组成;详细介绍了该中间件的通信过程及安全策略;在此基础上,开发了运用该中间件的实际系统。     

基于发布订阅机制的实时中间件的设计与实现

针对分布式系统节点分布、数据异构、任务动态的特点,研究中间件在功能和性能方面的需求,设计并实现了一个基于发布/订阅机制的实时中间件。采用分层设计的思想,依次从模型层、通信层和支撑层三个方面完成中间件的构建,使之具有基于分布式对象的数据同步功能、基于以太网的发布订阅通信机制及基于分布式对象的实时性能保障机制。经实验测试表明,该中间件在功能上满足了分布式系统应用的需要,在性能上保证了端到端数据通信延迟小于1毫秒,满足了分布式应用中数据分发对实时性的要求。     

中间件技术在铁道部调度指挥管理信息系统DMIS的应用

简要分析了铁道部调度指挥管理系统中面临多级数据通信的问题，介绍了中间件的一些基础知识，基于消处队伍机制的中间件应用到DMIS中，实现了广域网中跨系统平台，大量数据的实时通信。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

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.