基于先验知识的自适应多叉树防碰撞算法

为提高无线射频识别(RFID)系统快速识别大量标签的能力,提出一种基于先验知识的自适应多叉树防碰撞算法。利用标签访问的规律性和标签分布的随机性,在不同的搜索深度,根据已有的先验知识和碰撞比特信息估计待识别的标签数量,从而动态地自适应选择搜索叉树。通过有效减少碰撞和空闲时隙数,大幅提高读写器搜索和识别标签的能力。理论分析与仿真实验结果表明,该算法能克服传统自适应多叉树防碰撞算法的缺点,合理选择初始搜索叉树,尤其在待识别标签数量较多的场合,可有效提高RFID系统的吞吐率。     

基于前缀分组的改进自适应多叉树防碰撞算法

针对自适应多叉树防碰撞算法在标签识别过程中存在空闲时隙过多、系统吞吐量较低的问题,提出一种基于前缀分组的改进自适应多叉树防碰撞算法.算法分为前缀分组与标签识别两个阶段,前缀分组阶段阅读器使用一个查询周期确定范围内标签的查询前缀,每个前缀代表一个分组.标签识别阶段采用一种改进自适应多叉树防碰撞算法,通过计算碰撞因子,动态...     

基于分组动态帧时隙的RFID防碰撞算法

为了解决射频识别(RFID)系统中的多标签防碰撞问题,在分析帧时隙ALOHA算法的基础上,提出一种基于分组动态帧时隙的RFID防碰撞算法。当标签数量庞大时,该算法可以通过分组限制响应标签数量达到较高的识别效率。仿真结果表明,当标签数为1 000时,与传统算法相比,该算法能使时隙利用率提高80%以上。     

一种基于二进制码调制的射频识别防碰撞算法

针对射频识别( RFID)标签防碰撞算法识别效率低的问题,提出一种基于二进制码调制的RFID标签防碰撞算法BCMA。对传统多叉树防碰撞算法进行改进,活动标签采用位编码技术把标签ID在多叉数中的位置信息调制到一个2m位的二进制数主控继电器(MCR)上,并把MCR回送给阅读器;阅读器采用位跟踪技术,定位MCR碰撞发生的数位,从而解调出活动标签的分组信息。阅读器对待识别标签的分组是确定性的,进而避免空闲时隙的产生,提高系统识别效率。仿真结果表明,与常见的八叉树算法相比,BCMA算法使系统吞吐率提高168%。     

基于搜索树的增强型RFID防碰撞算法

针对RFID系统中采用多叉树搜索时存在空闲时隙、对碰撞节点处理缓慢等不足,提出一种基于搜索树的增强型RFID防碰撞算法。新算法利用读写器检测相邻碰撞位的个数,在搜索过程中不断自适应调整子二叉树的分配个数,综合选择无空时隙八叉树或四叉树或二叉树搜索方式。为消除多叉树搜索中产生的空闲时隙,阅读器先发送一个获取前缀命令确定标签前缀。理论分析和仿真结果表明,新算法的性能优于其他常用的标签防碰撞算法,大幅度减少了搜索总时隙数,降低了标签功耗,提高了系统搜索效率。     

分类响应限制的RFID防碰撞方法及应用

无线射频识别(RFID)在校园一卡通系统中已获得普遍使用.因为校园学生众多,情况比较繁杂,读写器碰撞与标签碰撞问题会导致较低的系统识别率,也将成为一卡通系统应用中的突出问题.针对此问题,对RFID防碰撞的动态帧时隙算法进行了改进,该算法通过分类响应限制标签个数,进而能够在标签数量很多的情况下提升系统的识别率,尤其适合应用在短时间内需要大量识别标签的校园一卡通应用环境中.仿真实验结果证明,该算法在短时间内进行大量RFID标签识别比传统时隙算法具有更高的效率.     

一种基于混合树防碰撞算法的改进算法

由于无线射频识别技术RFID(Radio Frequency Identification)现广泛应用于各个领域中,标签的碰撞问题也成为一个待解决的重要问题。根据现有多叉树防碰撞算法提出一种动态自适应多叉树防碰撞算法(DIHQT)。该算法根据碰撞位最高三位的连续性自行调节算法的搜索叉数,在没有附加查询的条件下,动态自适应地选择二叉树、四叉树或八叉树来查询标签ID编码。通过对算法性能分析和仿真实验结果可以表明,DIHQT算法在时间复杂度上有约200次的减少,以及识别效率上较其他算法都有约5%提高。     

一种新的RFID混合防碰撞算法

针对射频识别（RFID）系统随机性防碰撞算法中标签识别效率低的问题,提出了一种新的RFID混合防碰撞算法。新算法采用帧时隙ALOHA（FSA）机制,根据碰撞时隙数直接估计出总的未识读标签数目,经多次动态调整帧长,获得最优帧长,然后使读写器按照最优帧长分配时隙以供标签响应,在碰撞时隙内调用自适应搜索矩阵（ASM）算法对响应标签进行识别。理论研究和仿真表明,新算法有效实用,可有效提高系统性能,使时隙吞吐量达到40%以上。     

多标签快速识别算法的研究

解决RFID多标签碰撞问题常用的时隙aloha方法效率较低,二进制树方法要求区域内标签数喇不变.以提高aloha法的标签识别效率为目的,分析不同时隙内标签的碰撞个数,构建了标签碰撞的分布数学模型,分析最大时隙利用率,提出了一种多标签快速识别算法.该算法以阅读器发出的Query命令决定的时隙数为一段观察时间,对期间的标签响应状况进行统计分析以便对下一轮识别做出正确的指导,是一种动态帧时隙aloha算法.Msdab仿真结果表明,物流射频识别系统中,算法比时隙aloha算法的识别效率提高近一倍.     

后退锁位式RFID自适应多叉树防碰撞算法

针对无线射频识别技术系统中的标签碰撞问题,采用对碰撞位锁定的方法,提出了一种后退锁位式自适应多叉树防碰撞算法。在自适应多叉树防碰撞算法的基础上,通过碰撞锁位指令判断标签碰撞信息并将碰撞位信息提出来,结合后退式寻呼机制,在减少碰撞时隙的基础上,同时也减少了传输的数据量。仿真结果显示,该算法有更快的识别速度和更少的传输数据量。     

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。     

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.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.