结合EZW和AES的图像加密机制

随着图像或视频的网络应用日益普及,各种各样的新型应用不断涌现.由于图像或视频在网络中传输时,网络本身的安全措施并不能完全阻止非法截取事件的发生,因此人们对于图像数据传输的有效性和安全性提出新的要求.提出一种新的方法,其基本思想是通过结合使用离散小波变换(DWT)、嵌入式零树小波编码(EZW)和高级加密标准(AES),在对需要传输的图像充分压缩的基础上,对编码码流加密置乱,从而同时达到有效和安全传输的目的.实验结果表明,该方法在保持较高压缩效率的同时,增强了码流在传输过程中的安全性.     

大棚温湿度测控系统的设计

该系统由AT89S52单片机、温度检测电路、湿度检测电路、控制系统、报警电路、显示电路等组成,能够实现对大棚里植物生长温度及土壤和空气湿度的检测和监控,并对超过正常温度、湿度范围的状况进行实时处理,使大棚环境得到了良好的控制。该设计还具有对温度和湿度的显示功能,对大棚内环境温度和湿度的预设功能。     

Unique-order interpolative coding for fast querying and space-efficient indexing in information retrieval systems

This paper presents a size reduction method for the inverted file, the most suitable indexing structure for an information retrieval system (IRS). We notice that in an inverted file the document identifiers for a given word are usually clustered. While this clustering property can be used in reducing the size of the inverted file, good compression as well as fast decompression must both be available. In this paper, we present a method that can facilitate coding and decoding processes for interpolative coding using recursion elimination and loop unwinding. We call this method the unique-order interpolative coding. It can calculate the lower and upper bounds of every document identifier for a binary code without using a recursive process, hence the decompression time can be greatly reduced. Moreover, it also can exploit document identifier clustering to compress the inverted file efficiently. Compared with the other well-known compression methods, our method provides fast decoding speed and excellent compression. This method can also be used to support a self-indexing strategy. Therefore our research work in this paper provides a feasible way to build a fast and space-economical IRS.     

The Media and Educational Testing: In Pursuit of the Truth or in Pursuit of a Good Story?

The measurement community needs to better understand how to interact with the media to effectively disseminate important findings from educational testing efforts. To this end, the current paper will review media coverage of educational testing and related issues and elaborate on areas of concern and opportunities for improved communication between measurement professionals and the media. Common misinterpretations of test results and measurement concepts will be discussed and suggestions for the clearer presentation and explanation of such information will be offered. Also, practical advice and strategies for handling different types of interactions with the media will be provided. The implications of focusing on this topic in the measurement profession and the inherent public value of this focus are highlighted throughout the paper.     

Evaluating the Comparability of Paper‐ and Computer‐Based Science Tests Across Sex and SES Subgroups

As access and reliance on technology continue to increase, so does the use of computerized testing for admissions, licensure/certification, and accountability exams. Nonetheless, full computer‐based test (CBT) implementation can be difficult due to limited resources. As a result, some testing programs offer both CBT and paper‐based test (PBT) administration formats. In such situations, evidence that scores obtained from different formats are comparable must be gathered. In this study, we illustrate how contemporary statistical methods can be used to provide evidence regarding the comparability of CBT and PBT scores at the total test score and item levels. Specifically, we looked at the invariance of test structure and item functioning across test administration mode across subgroups of students defined by SES and sex. Multiple replications of both confirmatory factor analysis and Rasch differential item functioning analyses were used to assess invariance at the factorial and item levels. Results revealed a unidimensional construct with moderate statistical support for strong factorial‐level invariance across SES subgroups, and moderate support of invariance across sex. Issues involved in applying these analyses to future evaluations of the comparability of scores from different versions of a test are discussed.     

改革考核方式提高邓小平理论课教学质量

在高校的<邓小平理论概论>课教学中采取"多样化积分总评"考核新方式,能有效调动学生学习邓小平理论的自觉性和自主性,增强学生建设有中国特色社会主义的理想和信念.这是马克思主义理论课教学模式的改革与转换的有益尝试.     

船舶运动数据在字符与数值混合通信中的简易压缩方法

通过对船舶运动数据的分析,提出了在具体应用条件下一种船舶运动数据的简易压缩方法。     

基于小区域断点检测的P2P网络快速通行算法

提出一种自主感应分析算法,针对通信小区域内的断点,设计最优路径选取方法。计算路径中的相关断点权值,为每个路径的选择设计相关的阀值标准,选取最优路径,避免断点区域路径的选择,同时也避免了传统方法逐个遍历网络节点带来的通信效率过低的问题。实验证明,利用该方法能够快速选取通信最优路径,有效提高了P2P网络通信效率,取得了满意的结果。     

Equivalence of Population Variances: Synchronizing the Objective and Analysis

Researchers are often interested in establishing equivalence of population variances. Traditional difference-based procedures are appropriate to answer questions about differences in some statistic (e.g., variances, etc.). However, if a researcher is interested in evaluating the equivalence of population variances, it is more appropriate to use a procedure designed to determine equivalence. A simulation study was used to compare novel equivalence-based tests to traditional variance homogeneity tests under common data conditions. Results demonstrated that traditional difference-based tests assess equality of variances from the wrong perspective and that the proposed Levene-Wellek-Welch test for equivalence of group variances the best performing test for detecting equivalence. An R function is provided in order to facilitate use of this test for equivalence of population variances.     

基于指纹识别技术的实验室开放管理系统

介绍了指纹采集、比对在实验室开放管理系统中的用法，以及通过指纹的采集比对实现了学生的建档，实验台的分配、计时、控制及学生信息的查询、汇总。指纹技术的应用使得实验室开放管理更加方便、可靠、有效。