一种基于模糊神经网络的可靠流量控制模型

为控制P2P流量，本文从数据缓冲区使用的实时状态出发，提出了一种基于模糊神经网络的拥塞控制模型，该模型把缓冲区划分为两个队列分别存放P2P和非P2P的数据包，通过模糊神经网络预测评估缓冲区队列的拥塞状况，并建立一个评估函数对各队列的空间分配作出指导，使得能够控制各队列的拥塞状况，并动态的调整缓冲区队列的分配，在缓冲区溢出前主动丢包，避免缓冲区锁定。模拟实验的结果表明，该模型在保证网络资源分配的公平性方面取得了较好的效果，它降低了数据包排队延时和丢包率，提高了路由器处理网络拥塞的能力。     

基于累积时延的流媒体传输模糊拥塞控制

为保证网络流媒体传输质量,在流媒体的传输中需要采用有效的拥塞控制策略.结合流媒体数据对时延敏感的特点,提出了一种基于累积时延的模糊拥塞控制算法,该算法在流媒体数据流传输过程中检测和跟踪其时延,在转发分组数据前,根据容忍时延阈值,丢弃超时数据包,减少不必要的带宽浪费,并且对所到达的数据流按照累积时延进行优先级分类,把全局性缓冲区和各队列的局部性缓冲区按照正常、拥塞避免和拥塞的规则划分为3个具有交叉过渡域的阶段,然后采用整体和局部相结合的拥塞控制方法,实现队列调度过程中的模糊处理,从而对网络拥塞进行有效的控制.理论分析和实验结果表明,使用基于累积时延的模糊拥塞控制算法,能有效改善流媒体的传输性能,是解决流媒体传输拥塞控制的有效途径,并能对提高网络性能起到重要作用.     

基于模糊逻辑的拥塞控制研究

本文针对Internet拥塞控制提出一种新的基于模糊逻辑的主动队列管理策略。队列的状态转换成为语言变量输入，通过依据经验定义的模糊推理计算数据包的丢弃率。仿真结果表明采用模糊逻辑的主动队列管理策略具有良好的性能和鲁棒性。     

基于滑模变结构的无线传感器网络拥塞控制

为解决无线传感器网络逐跳节点拥塞控制问题,在节点网络层与链路层之间引入水槽流入与流出的数学模型,提出一种针对逐跳节点级链路层帧缓冲区队列长度的拥塞控制模型,并采用基于趋近律的离散滑模控制结构作为该模型的控制器,控制过程简便且易于实现。仿真结果表明,与常规的PID控制、模糊PID控制相比,该模型在响应速度、延迟时间等方面性能较好。     

自相似业务下拥塞避免机制的实现

传统拥塞避免机制所采用的随机早期检测（Random Early Detection,RED）算法是建立在网络流量按Poisson分布的基础上,因此不适应具有自相似业务流量特征的Internet网。针对自相似业务流量特点,对RED算法进行了改进,提出了一种基于时间间隔的随机早期检测（Based Interval Random Early Detection,BIRED）算法。BIRED算法能够在自相似业务流量特征下,通过控制平均队列长度,避免网络进入拥塞状态。通过仿真比较了BIRED和RED的动态性能,显示了BIRED具有更好的鲁棒性,证明了BIRED比RED、DropTail更能适应自相似业务流量,减小系统负担,有效稳定平均队列长度,改善系统的暂态特性。     

一种自适应的主动网络拥塞控制机制研究

传统的端到端的拥塞控制机制不适应主动网络,针对主动网络面临的拥塞问题,提出了一种自适应的主动网络拥塞控制解决方案.在中间节点为转发到相邻节点的主动信包建立缓冲队列,以缓冲区中队列长度来表明节点的拥塞程度,通过对前向节点计算单元进行控制来改变当前节点拥塞状况,网络中相关节点通过协作对网络进行拥塞控制.理论分析和模拟试验结果表明,不管网络初始状态如何,该方案均能使各节点迅速达到动态平衡,快速消除主动网络拥塞.     

互联网中的模糊滑模拥塞控制策略

针对互联网中的拥塞控制问题, 基于滑模控制理论及T-S（Takagi-Sugeno）模糊模型,提出了一种模糊滑模拥塞控制策略。考虑到互联网中存在的不确定和时变时滞因素,采用T-S模糊模型对网络系统进行了建模。利用线性矩阵不等式设计了一个渐近稳定的滑模面,有效地补偿了不确定及时滞因素的影响。基于趋近律的方法设计了控制器,有效地抑制了路由器中队列长度的振荡。多种情况下的仿真对比表明,所提出的控制策略具有更好的稳定性和鲁棒性。     

一种基于模糊理论的拥塞控制算法

路由器在处理拥塞时,通常把网络载荷分为正常、拥塞避免和拥塞三个阶段,并在拥塞避免阶段开始采取行动。由于各个阶段的描述存在一定的不确定性,因此一些传统的方法很难取得更好的效果。论文则充分利用模糊理论在处理不确定性问题上的优越性,采取整体和局部相结合的方法,从而在保证各TCP连接吞吐量的公平性方面,取得了比传统的方法更好的效果。实验仿真结果表明,模糊算法较传统方法更为合理,从而更好地改进了路由器的拥塞控制性能。     

一种针对TCP动态队列管理的控制算法

描述了一种新的TCP/IP动态队列管理控制算法, 对于传统的随机早期检测法(RED)来说, 它的主要目标之一就是稳定路由器队列的长度, 然而它实现此目标并不是很成功,主要因为它在平衡队列长度的过程中很强地依赖了动态TCP链接数. 而新的动态控制算法则使用了一种简单的控制方法, 当路由器缓冲区即将出现拥塞时, 它能够根据当前路由器缓冲区负载概率来随机地实施包丢弃. 该算法能够很好地稳定路由器缓冲区的队列占用数, 同时, 在实现过程中并不用评估动态TCP链接数以及分析网络流的状况.所给出的一个实验模型表明,该控制算法是有效可行的.     

一种支持优先级标记处理的主动队列管理机制

随着Internet流量的日益增加,依赖平均队列长度管理拥塞控制的RED(random early detection)队列管理算法有其内在的缺点,即使结合IETF(Internet engineering task force)明确的拥塞通知ECN(explicit congestion notification)也不能有效地阻止包丢失.在分析比较RED算法和BLUE算法的基础上,提出了一种加强的主动队列管理机制--EBLUE(enhanced BLUE),然后结合EBLUE研究了TCP的拥塞控制机制,     

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.