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在程序理解和软件逆向工程研究中,找到准确和快速地描述软件的设计模式和待识别源代码的方法,对于构建合理的设计模式识别框架和高效的识别算法是至关重要的。运用无向图的邻接表和连通分量的原理,提出类与类之间关联度的概念,由待识别源代码构建一个关联类集合,旨在减小设计模式识别算法的搜索空间;根据设计模式的特征,提出基于关联度和特征约束的设计模式识别算法。对Junit、JHotDraw和JreFactory 3个开源应用程序进行的设计模式识别表明,该算法能够准确高效地完成对源代码设计模式的识别。 相似文献
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在程序理解和逆向工程中,对软件设计模式的识别有助于软件技术人员从软件结构上理解系统的设计意图和实现功能。通常,采用UML类图表示的软件设计描述难以从特征上对设计模式进行准确的识别。提出一种基于XML Schema技术定义XML文档结构的设计模式定义语言——DPDLXS。通过运用DPDLXS语言描述特定设计模式的实例表明,该设计模式定义语言能够准确表述设计模式的特征,可以为设计模式的识别提供技术支持。 相似文献
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该文对维吾尔语的框架语义描述体系及内容进行了初步探讨和尝试,建立了维吾尔语框架语义文档的树型结构。根据维吾尔语框架语义知识库的描述内容及框架语义网络自身的特点,该文在数据库中以维吾尔语框架语义为核心进行信息存储,设计了语义知识库的概念模型。为创建基于认知的维吾尔语框架语义知识库建设探索了一条可行的技术路线、方法和思路。 相似文献
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设计模式对于构建可复用的软件框架有重要意义。本文用构造型说明法讨论了满足结构化要求的各种元设计模式应具备的语义特性。提出了用构造型说明来描述基于元模式的模式规约的思想。 相似文献
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本文研究面向语义检索的图像内容描述机制。首先提出图像语义检索整体框架,系统采用XML技术,将图像内容层式描述、图像语义对象自动获取、图像语义相似测度等功能模块加以融合,实现语义层面的图像检索。重点对系统框架中与图像内容描述相关的图像特征分层描述模型、空间位置算子定义、语义对象操作等关键技术进行讨论,并定义相应的XML语义描述框架。检索实验结果表明,该方法具有较好的语义检索性能。 相似文献
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基于抽象解释的代码迷惑有效性比较框架 总被引:8,自引:0,他引:8
代码迷惑是一种以增加理解难度为目的的程序变换技术,用来保护软件免遭逆向剖析.代码迷惑是否有效是代码迷惑研究中首要解决的问题.目前对有效性证明的研究大都是基于非语义的方式.文章将语义与有效性证明联系起来,建立了基于语义的代码迷惑有效性比较框架,该框架能够为迷惑算法在静态分析这样的限定环境下提供有效性证明,而且也能严格比较迷惑算法之间的有效性,最后使用实例描述比较框架如何应用到证明代码迷惑的有效性. 相似文献
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OBJECTIVE: To examine operator strategies for diagnosing and recovering from errors and disturbances as well as the impact of automation design and time pressure on these processes. BACKGROUND: Considerable efforts have been directed at error prevention through training and design. However, because errors cannot be eliminated completely, their detection, diagnosis, and recovery must also be supported. Research has focused almost exclusively on error detection. Little is known about error diagnosis and recovery, especially in the context of event-driven tasks and domains. METHOD: With a confederate pilot, 12 airline pilots flew a 1-hr simulator scenario that involved three challenging automation-related tasks and events that were likely to produce erroneous actions or assessments. Behavioral data were compared with a canonical path to examine pilots' error and disturbance management strategies. Debriefings were conducted to probe pilots' system knowledge. RESULTS: Pilots seldom followed the canonical path to cope with the scenario events. Detection of a disturbance was often delayed. Diagnostic episodes were rare because of pilots' knowledge gaps and time criticality. In many cases, generic inefficient recovery strategies were observed, and pilots relied on high levels of automation to manage the consequences of an error. CONCLUSION: Our findings describe and explain the nature and shortcomings of pilots' error management activities. They highlight the need for improved automation training and design to achieve more timely detection, accurate explanation, and effective recovery from errors and disturbances. APPLICATION: Our findings can inform the design of tools and techniques that support disturbance management in various complex, event-driven environments. 相似文献
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在高速串行接口芯片的设计中,高速串行数据恢复电路是设计中的一个难点,由于其高达千兆的传输频率,大多采用模拟电路方式实现·然而同数字电路相比,模拟电路在噪声影响、面积、功耗、工艺敏感度和可测性方面都存在较大的劣势·提出了一个应用于SATA1·0中1·5Gbps高速串行接口的高速串行数据恢复电路,它没有用PLL或DLL等模拟电路的方法,它采用完全数字电路的设计,并用标准单元实现·与用模拟电路实现的串行数据恢复电路相比,此电路设计更加简单易实现,数据恢复快速,而且面积小功耗低·电路被应用在PATA/SATA桥接芯片的设计中,并在标准0·18CMOS工艺下投片生产· 相似文献
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This paper applies the proportional-integral (PI) observer in connection with loop transfer recovery (LTR) design for continuous-time systems. We show that a PI observer makes it possible to obtain time recovery, i.e., exact recovery for t →∞, under mild conditions. Based on an extension of the LQG/LTR method of proportional (P) observers, a systematic LTR design method is derived for the PI observer. Our recovery design method allows time recovery and frequency (normal) recovery to be done independently. Furthermore, we give explicit expressions for the recovery error when asymptotic recovery cannot be obtained. A design example demonstrates the advantages of time recovery in the non-minimum phase case. 相似文献
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为除去DEM粗产品中的少量乙醇,获得高纯度DEM产品,测定乙醇-DEM体系的汽液平衡数据,采用间歇精馏法将体系分离精制.确定了精馏工艺条件,考查了原料组成、填料高度等因素对分离的影响,采用理论板数n≥28的填料蒸馏塔,当原料中乙醇含量等于2%时,产品DEM纯度町高于99.6%,回收率超过88%.为以后的工业装置设计及工业化生产提供了充足的实验依据. 相似文献
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This paper discusses a regenerative braking system for the electric motorcycle that performs regenerative energy recovery based on neural network control with a boost converter. A constant regenerative current control scheme is proposed, thereby providing improved performance and high energy recovery efficiency at minimum cost. The neural network controller is used to simulate the regenerative system in Matlab/Simulink and neural network toolbox. We can sieve out the suitable training samples to obtain good performance of the controllers, and the neural network with genetic algorithms is used to design the controller. Simulation results of neural network controller show a more steady quality and extended time of charging. The proposed scheme not only increases the traveling distance of the vehicle but also improves the performance and life-cycle of batteries, and the energy recovery of batteries becomes more stable. Therefore, the market of the electric vehicle will become more competitively. 相似文献
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一种持续数据保护系统的设计与实现 总被引:1,自引:0,他引:1
魏冰璐 《计算机应用与软件》2009,26(6):146-148
随着数据增长速度的不断加快,数据可用性变得比以往任何时候都更加重要。持续数据保护是一套数据灾难恢复方法,它可以捕获或跟踪数据的变化,并将数据恢复到任意时间点。在改进数据压缩算法和系统架构的基础上设计并实现一个基于iSCSI的持续数据保护系统。对系统进行数据测试结果显示该系统很好地解决了传统持续数据保护系统中数据占用空间大、恢复时间慢、可靠性低的缺点,能很好地将数据恢复到任何时间点,并给出简要的分析。 相似文献
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随着芯片密度的不断增加和对可靠性要求的不断提高,高性能处理器的容错设计越来越受到关注.对近年来高性能处理器的差错校正技术进行了分析和比较,它们被分为时钟级差错恢复、指令级差错恢复、线程级差错恢复以及重构等4类,研究对象包括研究方案、原型和产品.研究结果表明,以片上多处理器和/或同时多线程为特征的高性能处理器除了沿用传统的容错技术之外,多以固有的、旨在为改善性能而重复设置的硬件资源为基础来设计容错机制和调度方案. 相似文献
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一种工程数据库日志管理系统的设计与实现* 总被引:4,自引:0,他引:4
探讨了一种工程数据库管理系统中的日志管理子系统的设计和实现方法。该方法以LSN(Log Sequence Number)来组织日志记录,用于实现日志记录的高效存储和读取,提高数据库实例恢复和事务回滚的速度,在此基础上可以实现ARIES协议。 相似文献