基于ACM/ICPC在线测评系统的设计

针对ACM国际大学生程序设计竞赛培训教学中程序评测的需求,开发程序在线测评系统。系统基于Apache服务器,采用PHP和MYSQL数据库技术运行于Windows Sever 2003平台。采用软件工程黑盒测试的思想对用户提交的程序进行测评,系统主要分为三个部分：网站部分,数据库部分及测评部分。数据库部分对系统提供数据存储支持;网站部分则是系统与用户的交互接口;测评部分则是对用户提交程序运行的主要控制部分,它将控制提交程序的运行时间以及内存,并对运行程序的结果进行判断。     

基于ACM/ICPC在线测评系统的设计

针对ACM国际大学生程序设计竞赛培训教学中程序评测的需求,开发程序在线测评系统。系统基于Apache服务器,采用PHP和MYSQL数据库技术运行于Windows Sever 2003平台。采用软件工程黑盒测试的思想对用户提交的程序进行测评,系统主要分为三个部分:网站部分,数据库部分及测评部分。数据库部分对系统提供数据存储支持;网站部分则是系统与用户的交互接口;测评部分则是对用户提交程序运行的主要控制部分,它将控制提交程序的运行时间以及内存,并对运行程序的结果进行判断。     

基于Linux的ACM在线评测系统研究

ACM竞赛是目前计算机水平最高的国际大学生程序设计竞赛,而ACM在线评测系统则是根据竞赛需求而提供的一个培训平台。由于Linux系统具有安全性高、稳定等优点,目前大部分服务器都是使用Linux系统。本文提出一个基于Linux的ACM在线评测系统,详述该系统中编译、测试、获取计算机消耗情况、返回测试结果这几种功能的具体实现。并分析该系统中可能出现恶意占用资源、恶意调用系统等不安全因素,提出相应的解决方案。该系统具有实用性强、安全性好等优点。     

一种基于ACM程序设计竞赛在线评测系统解决方案

分析了一种基于ACM程序设计竞赛在线评测系统的基本原理及系统的构成,重点阐述了程序性能评判原理及实现方法.对通信安全、资源占用等关键问题给出了相应的解决方案,主要模块给出了相应代码.     

基于竞赛模式的“算法分析与设计”教学探索与实践

本文分析了程序设计竞赛的特点及算法分析与设计课程教学中存在的问题,利用程序在线评测平台,提出了基于程序设计竞赛的教学模式,并在教学中进行了实践。     

基于Web的ACM/ICPC自动评测系统的设计与实现

针对现有ACM程序设计竞赛评判系统存在的缺陷,采用了新的架构模式,设计了用于大学生程序设计训练和竞赛的自动评测系统,实现了对用户提交的程序源代码进行自动编译、连接、运行、测试、评审等过程并返回测试结果,采用了多进程的并发处理、信号处理、进程通信、文件管理等技术,使得该自动测评系统在实际应用过程中发挥良好的性能,完成了日常编程训练和各类网上程序设计竞赛活动,体现了竞赛过程的自动化、高效率、公正性等特性。     

源程序在线评测系统的设计与实现

源程序在线评测系统是一个基于网络的通用程序设计语言的自动评测系统,该系统为学生学习基本的程序设计语言提供了良好的训练平台,培养学生程序设计的兴趣,提高学生程序设计的能力。     

一种新型的Online Judge的设计与实现

针对传统程序设计在线评测系统（online Judge）存在的缺陷,开创性地提出并设计了一种新型的评测系统。新的系统允许用户提交非完整的程序,能够更好地支持函数教学、面向对象程序设计的教学,全面满足程序设计课程的实际教学需要。     

《程序设计》课程教学方法新探

针对当前《程序设计》课程教学中存在的问题,根据多年来从事该课程教学的经验,同时结合指导学生参加ACM国际大学生程序设计竞赛的经验,提出相应的改革措施,包括淡化语法,重视解题思路、解题方法的培养,利用单步执行程序帮助学生理解程序设计的相关知识,利用在线评测系统加强实践环节,调动学生上机实践的积极性。     

对HUSTOJ在线评测系统的若干优化与创新

在原有HUSTOJ开源在线评测系统的基础之上,分别对系统的竞赛模式的类别、竞赛的权限设置、用户信息的处理、系统的数据库结构进行修改与创新。使得新的系统相比原有的系统竞赛方式更多样,竞赛和整个系统之间的数据更加的独立,不会产生相互的干扰;而且使得用户信息的统计更加科学和合理化。     

Coding behavior of authentication code on the internet

With the rapid growth of Internet services, virtual world has witnessed an increasingly large number of online users who have a variety of needs such as accessing various websites to gather information, easing business transactions, and sharing updates. As a result, information security has become a major concern among online users, and the verification of access codes is now the main practice used to keep information systems safe. However, some issues arise as the result of coding and managing behavior, and this research seeks to address these issues. After following the Focus Group method and interviewing 13 college students, this research finds that forgetting the access code is one of the biggest challenges to most online users simply because of the longer duration and the time when the users have a need to access the websites again, their memory will eclipse. In addition, online users usually develop self-constructed rules to cope with elusive code. These rules include: creating some sets of code that may not be meaningful to outsiders; taking different degrees of complex measures to register authentication codes, dependent upon the importance of the websites to the online users; writing the authentication codes on a scratchpad and sticking it on the computer screen; and keeping the codes in a notebook or computer file. The above practices nevertheless run the risk of being usurped by hackers, and it is found that hacking frequently takes place among closest friends, as they are quite familiar with the coding behavior of the victims. While assisting coding management does not help in this regard, as it is generally too expensive, online users troubled by the forgetting of access codes often end up with re-applying for a new set of authentication codes after unsuccessfully trying to login. All these self-constructed rules, nevertheless, constitute threat to information security. The research, in conclusion, calls for an education campaign to promote healthy coding behavior and effective coding management. The obtained findings provide valuable references for both academicians and practitioners to understand the online users’ coding behaviors and to effectively manage them accordingly to improve the resulting information security.     

基于镜像的在线文件系统检查工具的研究与实现

设计和实现了一种全新的在线文件系统检查工具-OnlineFSCK(On-Line File System Checker)。 OnlineFSCK可以对在线的文件系统进行一致性检查。利用OnlineFSCK对文件系统进行检查时,文件系统可以继续正常提供服务。提出和实现了一种对在线文件系统生成镜像的算法,并将这个算法与现有的文件系统检查工具相结合,最终达到对在线文件系统进行检查的目的。针对ext3文件系统实现了OnlineFSCK的原型,实验结果表明, OnlineFSCK 在满足对性能的要求的前提下,能够达到与传统文件系统检查工具相同的检查能力。 OnlineFSCK的实现中没有修改文件系统的内核源码,可以扩展支持多种文件系统。     

Crossing the Line or Making the Case?

Anyone who has searched the Internet for products and services has experienced the wonderful assortment of products, services and resources that can be found online. We are witnessing the rapid growth of truly global commerce with unparalleled opportunity for choice and selection, competition and more. However, when criminals operating in another nation attack, the operators of E-commerce systems confront one of the most serious downsides of global operations since there is little or no commonality on how police officials in various nations will respond. Possible conflicts can arise in the absence of common codes of criminal conduct, standards of collaboration and consensus as to how the “civilized” forces of law and order will proceed against the denizens of the “dark side”.     

联机手写笔画特征抽取的逼近-合并算法

为了对联机手写字符识别的笔画进行精确描述,提出了一种基于字符笔画特征抽取的＂逼近-合并＂算法.该算法分析了字符笔画的多边形逼近,求出偏离度最小的多边形逼近,并对该多边形的边进行合并,抽取出笔画方向码,实现了联机手写字符笔画的更有效合并.该方法应用在联机手写体字符识别实验系统中,其识别率为99.13%.     

Matlab/RTW EC面向MC9S12D64的自动代码生成

传统的电控软件开发模式已无法满足日益庞大、复杂的汽车电控系统的开发要求,基于模型的开发方法以及自动代码生成技术在汽车嵌入式软件开发中得到越来越广泛的应用。本文介绍使用Matlab/Real-Time Workshop Embedded Coder(Matlab/RTW EC)将Simulink控制模型生成C代码以及生成代码与Freescale MC9S12D64单片机底层代码的集成方法,通过测试验证了生成代码的有效性。     

存储系统中的纠删码研究综述

随着海量存储系统的发展和在复杂环境中的应用,存储系统的可靠性受到了严重的挑战.纠删码作为存储系统容错的主要方法越来越受到重视.首先介绍了当前典型和常见的纠删码技术的发展现状,从评价纠删码性能的各项重要指标的角度详细地对比和分析了现有的纠删码技术,给出了不同纠删码在容错能力与磁盘要求、空间利用率、编码效率、更新效率、重构效率等方面的不足和可能的改进见解,并讨论了磁盘阵列系统、P2P存储系统、分布式存储系统、归档存储系统等不同存储系统对于纠删码各类性能的差别要求,并进一步指明了当前存储系统纠删码研究中尚未解决的一些难题和未来纠删码可能的发展方向.通过分析得出,目前不同纠删码在容错能力、计算效率、存储利用率等方面都存在不同程度的缺陷,如何平衡这些影响纠删码性能的因素,设计出更高容错能力、更高计算效率及更高存储利用率的纠删码,仍是未来很长一段时间内值得不断深入研究的问题.     

减少重建数据量的冗余编码技术研究

为防止硬件故障或机器宕机导致的数据丢失,冗余编码技术被广泛应用于分布式存储系统中来保证数据的可靠性。然而,传统的冗余编码技术,如里德-所罗门码,存在着重建数据量大的问题。副本技术在重建丢失数据时只需要读取和传输丢失的数据,而冗余编码需要读取和传输更大的数据量,从而消耗更多的磁盘I/O带宽和网络带宽。因此,基于冗余编码的分布式存储系统在重建数据时将消耗更长的时间,从而将整个系统长时间暴露在一种降级的模式下,进而增加了发生永久性数据丢失的风险。为解决这个问题,减少重建数据量的冗余编码技术不断被提出,然而只有这些冗余编码与传统的里德-所罗门码的比较,缺少它们在存储系统的综合比较。系统地从减少重建数据量等几个重要方面研究了这些减少重建数据量的冗余编码技术,从而为实际系统中采用合适的编码提供重要参考和依据。     

Multiple level orthogonal codes and their application in MC-CDMA systems

This paper proposes the use of multiple level orthogonal (MLO) codes in multicarrier CDMA (MC-CDMA) systems. It is extremely challenging to improve system error probability performance of MC-CDMA systems with binary spreading codes in multi-user conditions, since attainable-diversity performance is severely degraged by multi-user interference (MUI) in frequency-selective fading channel conditions, even with the use of optimum multi-user detection (MUD) methods. MLO codes are shown to improve system error probability performance in heavily-loaded or fully-loaded systems, in comparison to binary codes. Some widely used MLO code generation methods are summarized, and a new generation method is also provided. The performance advantage of MLO codes over binary codes is analyzed by treating the spreading process in MC-CDMA as a coding process and via analysis of pair-wise sequence error probability. Rules for choosing desirable MLO codes for multi-user MC-CDMA are also given. Numerical results show that MLO codes can provide a substantial performance improvement in fully-loaded systems. For example, for a K = 4 user system with spreading gain L = 4, our system can obtain a diversity order of 3, whereas the binary code system diversity order is only slightly larger than 1. The MLO code application provides a new way to compensate for multi-user interference (MUI) and makes MC-CDMA more attractive for future high data-rate transmission systems.     

Exploring creative thinking in graphically mediated synchronous dialogues

This paper reports on an aspect of the EC funded Argunaut project which researched and developed awareness tools for moderators of online dialogues. In this study we report on an investigation into the nature of creative thinking in online dialogues and whether or not this creative thinking can be coded for and recognized automatically such that moderators can be alerted when creative thinking is occurring or when it has not occurred after a period of time. We outline a dialogic theory of creativity, as the emergence of new perspectives from the interplay of voices, and the testing of this theory using a range of methods including a coding scheme which combined coding for creative thinking with more established codes for critical thinking, artificial intelligence pattern-matching techniques to see if our codes could be read automatically from maps and ‘key event recall’ interviews to explore the experience of participants. Our findings are that: (1) the emergence of new perspectives in a graphical dialogue map can be recognized by our coding scheme supported by a machine pattern-matching algorithm in a way that can be used to provide awareness indicators for moderators; (2) that the trigger events leading to the emergence of new perspectives in the online dialogues studied were most commonly disagreements and (3) the spatial representation of messages in a graphically mediated synchronous dialogue environment such as Digalo may offer more affordance for creativity than the much more common scrolling text chat environments. All these findings support the usefulness of our new account of creativity in online dialogues based on dialogic theory and demonstrate that this account can be operationalised through machine coding in a way that can be turned into alerts for moderators.     

编码器自动监测与故障诊断系统的研究与实现

文中介绍了某大型机电设备编码器的实时监测与故障诊断系统的设计工作.系统采用在线和离线两种工作方式,实现了接触式编码器的监测和诊断.系统硬件主要电路板基于PC104总线结构,18路I/O通道(9路输入,9路输出)完成9位编码器的检测和诊断.系统软件界面友好,巧妙地实现了格雷码与角度值的转换.本系统对其他编码器自动监测和故障诊断系统具有重要的借鉴意义.