一种JPEG无损压缩算法的仿真与实现

研究图像压缩算法优化算法的效果,针对目前通用无损压缩算法都难以对JPEG文件进行压缩,提出了一种洗牌算法和无损压缩算法相结合的无损压缩方法。在将JPEG图像文件进行压缩前对文件进行有效规整,产生冗余,然后再结合通用无损压缩算法进行无损压缩进一步去除文件内部信息冗余。进行仿真实验验证,算法能够进一步将JPEG图像文件无损压缩1%-3%。结果表明,上述算法能进一步无损去除文件内部冗余,减小文件体积,算法简单,时间复杂度低,易于实现,是一种有效的快速图像压缩算法。算法已经获得专利保护。     

Recommendation systems for decision support: An editorial introduction

This special section is focused on recommendation systems, computer-based information systems that provide suggestions based on previous usage behavior. The papers included in this section were selected from the Pacific Asia Conference on Information Systems (PACIS) and Workshop on Electronic Business (WEB). The application domains include website browsing aids, knowledge recommendation, document clustering, and team staff selection. They provide a snapshot of current development in using recommendation systems for decision support.     

On technology for functional requirement-based reference design retrieval in engineering knowledge management

Engineering design is a knowledge-intensive process, and includes conceptual design, detailed design, engineering analysis, assembly design, process design, and performance evaluation. Each of these tasks involves various aspects of technical knowledge and experience. Whether this technical knowledge and experience can be effectively shared is key to increasing product development capability and quality, and also to reducing the duration and cost of the development cycle. Consequently, providing engineering designers various query methods for retrieving engineering knowledge is one of the most important tasks in engineering knowledge management.The study develops a technology for functional requirement-based reference design retrieval as a decision support mechanism, which can assist engineering designers to retrieve relevant design and associated knowledge for reference in conducting functional requirements of a product. This study involves the following tasks: (i) designing a functional requirement-based reference design retrieval process, (ii) developing techniques related to the technology for functional requirement-based reference design retrieval, and (iii) implementing a functional requirement-based reference design retrieval mechanism. The retrieval process includes the steps of functional requirement-based query, case searching and matching, and case ranking. The technology involves (i) a structured query model for functional requirements, (ii) an index structures for historical design cases, (iii) functional requirement-based case searching and matching mechanisms, (iv) a functional requirement-based case ranking mechanism, and (v) a case-based representation of designed entities. Finally, the experimental example with indexing and retrieving similar designed entities is conducted to demonstrate the proposed techniques worked efficiently.     

Typology of teacher perception toward distance education issues – A study of college information department teachers in Taiwan

The popularity of distance education has grown rapidly over the last decade in Taiwan’s higher education, yet many fundamental teaching–learning issues are still in debate. While teacher–student interaction is a key success factor in distance education, little work has been done on the teachers. The intent of this research was to clarify teacher’s perceptions on key distance education issues and to develop a discernible typology of different groups of teachers based on their perceptions. Because there may be a gulf between teachers and the technology used in distance education, the target of this study was teachers in information related departments in Taiwan’s colleges, who were more familiar with current technology. Factor analysis and cluster analysis were used to derive the typology. Five higher-level issue constructs emerged from the factor analysis: learning effect, customization, administrative challenges, geographic and resource integration, and instructional design challenges. Four groups of teachers, namely the skeptics, the optimists, the mild-promising group, and the outlier, were identified using cluster analysis of teachers’ perceptions on these five higher-level issue constructs. The profiles of the four groups of teachers were summarized and implications were discussed, which should provide useful insights to the policy makers of higher education on distance education decisions.     

Network traffic classification based on ensemble learning and co-training

Classification of network traffic is the essential step for many network researches. However,with the rapid evolution of Internet applications the effectiveness of the port-based or payload-based identifi-cation approaches has been greatly diminished in recent years. And many researchers begin to turn their attentions to an alternative machine learning based method. This paper presents a novel machine learning-based classification model,which combines ensemble learning paradigm with co-training tech-niques. Compared to previous approaches,most of which only employed single classifier,multiple clas-sifiers and semi-supervised learning are applied in our method and it mainly helps to overcome three shortcomings:limited flow accuracy rate,weak adaptability and huge demand of labeled training set. In this paper,statistical characteristics of IP flows are extracted from the packet level traces to establish the feature set,then the classification model is created and tested and the empirical results prove its feasibility and effectiveness.     

基于时空混沌的视频流加密算法

基于视频具有数据量大、实时性要求高等特点,在一维耦合映像格子模型的基础上,对耦合格点结构和动力学模型这两个方面进行了改进,在系统结构上采用一维链加二维网格再加上一维链的组合模型来构造驱动和响应系统及多级加密的方案.实验结果表明,系统在增强密钥序列复杂度的同时也提高了加密效率,使得系统的抗破译能力大大加强.     

基于可变染色体长度的遗传K均值聚类算法

针对传统K-均值聚类算法需要事先确定聚类数,以及对初始质心的选择具有敏感性,从而容易陷入局部极值点的缺点,使用了一种基于可变染色体编码长度的遗传算法对传统K-均值聚类进行改进.该算法可以在事先不确定K值的情况下,通过多次的选择、交叉.变异的遗传操作,最终得到最优的聚类数,以及最优的初始质心集.通过Reuters数据集的实验结果表明,基于该算法的聚类划分结果明显优于传统K-均值聚类算法,并且好过基于固定染色体编码长度遗传算法的K-均值聚类算法.     

Orthogonal Methods Based Ant Colony Search for Solving Continuous Optimization Problems

Research into ant colony algorithms for solving continuous optimization problems forms one of the most significant and promising areas in swarm computation. Although traditional ant algorithms are designed for combinatorial optimization, they have shown great potential in solving a wide range of optimization problems, including continuous optimization. Aimed at solving continuous problems effectively, this paper develops a novel ant algorithm termed ＂continuous orthogonal ant colony＂ （COAC）, whose pheromone deposit mechanisms would enable ants to search for solutions collaboratively and effectively. By using the orthogonal design method, ants in the feasible domain can explore their chosen regions rapidly and efficiently. By implementing an ＂adaptive regional radius＂ method, the proposed algorithm can reduce the probability of being trapped in local optima and therefore enhance the global search capability and accuracy. An elitist strategy is also employed to reserve the most valuable points. The performance of the COAC is compared with two other ant algorithms for continuous optimization -API and CACO by testing seventeen functions in the continuous domain. The results demonstrate that the proposed COAC algorithm outperforms the others.     

真空条件下辅酶Q_(10)的β-环糊精包合物的动力学模拟

首先通过分子力学法,确定辅酶Q10(CoQ10)的7个β-环糊精(β-CD)包合物(CoQ10-7-β-CDs)的最稳定优势构型.并进一步用分子动力学法模拟真空状态,一定时间内包合物的动态结构,并统计分析CoQ10包合前后结构的变化对性质的影响.结果表明CoQ10分子可以通过范德华力、库仑作用和氢键一起作用于β-CD分子形成1:7的稳定的D型包合结构.包合后,CoQ10分子的C=O双键和醌环上的C=C双键增长,侧链上的C=C双键缩短,其活性部位的抗氧化能力增大,而分子骨架的稳定性增强.     

用改进的竞争Hopfield神经网络求解多边形近似问题

多边形近似是提取曲线特征点和简化曲线描述的一种重要方法.提出一种改进的Hopfield神经网络多边形近似算法,该算法利用选择拐点策略减少了搜索空间,重新定义了神经网络的能量函数,使其更能反映优化目标;引?入合并拆分搜索策略,有效帮助神经网络脱离局部最小值.实验结果表明,提出的改进算法是有效的,比其它算法如关键点检测法、竞争Hopfield神经网络、混沌Hopfield神经网络、遗传算法等具有更优的性能.