14 resultados para 080303 Computer System Security

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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为解决当前系统环境中应用安全与系统安全互相独立而存在的问题,提出了安全管道和TCB扩展的概念,给出了安全管道的形式化描述,并抽象出一种基于安全管道的TCB扩展模型,说明如何利用TCB扩展构建安全机制间的信息交互机制,以实现不同安全机制之间的统一.通过对TCB扩展模型的安全性分析,进一步说明了模型的科学性和现实可行性.

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在总结前人工作的基础上,结合安全操作系统对测试的特殊需求,提出了简并测试集(degenerate test set,简称DTS)的概念,设计了一种使用模型检测的基于安全状态转移的高效测试集生成方法.该方法以状态转移为化简对象,在利用模型检测技术生成测试用例的同时,归并相同的状态转移并化简需求集中的冗余属性,从而最终达到化简测试集的目的.在此基础上,探讨了单个用例失败时用例集的有效性问题,并对DTS生成算法进行了改进.实验结果表明,该方法可以有效地对测试集中的冗余进行化简.

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There is a need to obtain the hydrologic data including ocean current, wave, temperature and so on in the South China Sea. A new profiling instrument which does not suffer from the damage due to nature forces or incidents caused by passing ships, is under development to acquire data from this area. This device is based on a taut single point mid-water mooring system. It incorporates a small, instrumented vertically profiling float attached via an electromechanical cable to a winch integral with the main subsurface flotation. On a pre-set schedule, the instrument float with sensors is winched up to the surface if there is no strip passing by, which is defined by an on-board miniature sonar. And it can be immediately winched down to a certain depth if the sonar sensor finds something is coming. Since, because Of logistics, the area can only be visited once for a long time and a minimum of 10 times per day profiles are desired, energy demands are severe. To respond to these concerns, the system has been designed to conserve a substantial portion of the potential energy lost during the ascent phase of each profile and subsequently use this energy to pull the instrument down. Compared with the previous single-point layered measuring mode, it is advanced and economical. At last the paper introduces the test in the South China Sea.

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In the paper through extensive study and design, the technical plan for establishing the exploration database center is made to combine imported and self developed techniques. By research and repeated experiment a modern database center has been set up with its hardware and network having advanced performance, its system well configured, its data store and management complete, and its data support being fast and direct. Through study on the theory, method and model of decision an exploration decision assistant schema is designed with one decision plan of well location decision support system being evaluated and put into action. 1. Study on the establishment of Shengli exploration database center Research is made on the hardware configuration of the database center including its workstations and all connected hardware and system. The hardware of the database center is formed by connecting workstations, microcomputer workstations, disk arrays, and those equipments used for seismic processing and interpretation. Research on the data store and management includes the analysis of the contents to be managed, data flow, data standard, data QC, data backup and restore policy, optimization of database system. A reasonable data management regulation and workflow is made and the scientific exploration data management system is created. Data load is done by working out a schedule firstly and at last 200 more projects of seismic surveys has been loaded amount to 25TB. 2. Exploration work support system and its application Seismic data processing system support has the following features, automatic extraction of seismic attributes, GIS navigation, data order, extraction of any sized data cube, pseudo huge capacity disk array, standard output exchange format etc. The prestack data can be accessed by the processing system or data can be transferred to other processing system through standard exchange format. For supporting seismic interpretation system the following features exist such as auto scan and store of interpretation result, internal data quality control etc. the interpretation system is connected directly with database center to get real time support of seismic data, formation data and well data. Comprehensive geological study support is done through intranet with the ability to query or display data graphically on the navigation system under some geological constraints. Production management support system is mainly used to collect, analyze and display production data with its core technology on the controlled data collection and creation of multiple standard forms. 3. exploration decision support system design By classification of workflow and data flow of all the exploration stages and study on decision theory and method, target of each decision step, decision model and requirement, three concept models has been formed for the Shengli exploration decision support system including the exploration distribution support system, the well location support system and production management support system. the well location decision support system has passed evaluation and been put into action. 4. Technical advance Hardware and software match with high performance for the database center. By combining parallel computer system, database server, huge capacity ATL, disk array, network and firewall together to create the first exploration database center in China with reasonable configuration, high performance and able to manage the whole data sets of exploration. Huge exploration data management technology is formed where exploration data standards and management regulations are made to guarantee data quality, safety and security. Multifunction query and support system for comprehensive exploration information support. It includes support system for geological study, seismic processing and interpretation and production management. In the system a lot of new database and computer technology have been used to provide real time information support for exploration work. Finally is the design of Shengli exploration decision support system. 5. Application and benefit Data storage has reached the amount of 25TB with thousand of users in Shengli oil field to access data to improve work efficiency multiple times. The technology has also been applied by many other units of SINOPEC. Its application of providing data to a project named Exploration achievements and Evaluation of Favorable Targets in Hekou Area shortened the data preparation period from 30 days to 2 days, enriching data abundance 15 percent and getting information support from the database center perfectly. Its application to provide former processed result for a project named Pre-stack depth migration in Guxi fracture zone reduced the amount of repeated process and shortened work period of one month and improved processing precision and quality, saving capital investment of data processing of 30 million yuan. It application by providing project database automatically in project named Geological and seismic study of southern slope zone of Dongying Sag shortened data preparation time so that researchers have more time to do research, thus to improve interpretation precision and quality.

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最小特权机制可为安全操作系统提供恰当的安全保证级.本文描述了一种支持动态调节的最小特权安全策略架构,它结合角色的职责隔离和域的功能隔离特性,通过一种基于进程上下文一角色、执行域和运行映像的权能控制机制,将每个进程始终约束在这些上下文允许的最小特权范围内.本文实例分析了该架构在安胜OS v4.0,一种自主开发的、符合GB17859-1999第四级--结构化保护级的安全操作系统中的实现.结果表明,它可支持安全操作系统实施动态调节的最小特权控制,并提供灵活有效的系统.

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多数支持POSIX权能机制的安全操作系统提出了各自的权能遗传算法,但这些算法都只适用于特定的最小特权控制策略,并且存在语义冲突、安全目标不明确等问题,不能有效支持多种安全需求不同的特权策略。通过对一些现有算法的深入分析,提出了一种新的权能遗传算法,该算法引入策略关联的权能控制变量以及可信应用属性。实例分析表明本算法具有策略适应性和可用性,形式化分析和验证表明它可使系统满足特权策略的基本安全定理。

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介绍了863智能机器人型号之一──以核工业为应用背景的“勇士号”遥控移动式机器人的作业内容及其主要功能指标,分析了该型号的总体设计思想,同时概括总结了其操作性能、移动性能及计算机系统等方面的技术特点。

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本文介绍遥控移动式作业机器人实时多任务管理系统.该系统是在多总线和位总线相结合的计算机系统上,利用iRMXⅡ实时多任务操作系统设计编制的实时多任务管理系统.该系统为遥控机器人提供了数据通讯,人机接口,任务作业等重要管理工作,使机器人能顺利地完成机械手操作和车体运动等重要控制功能。

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本文阐述了在小型计算机上建立的 GPSS-F/1000通用仿真软件包。该软件包不仅具有原 GPSS-F仿真软件的全部功能,并且使公用数组、系统参数的适配全部活化,通过子程序的形式参量传送赋给,从而,仿真时不必修改子程序的源程序。此外,增加了统计参数估计子程序集和图形绘制子程序集。

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Based on the computer integrated and flexible laser processing system, an intelligent measuring sub-system was developed. A novel model has been built up to compensate the deviations of the main frame-structure, and a new 3-D laser tracker system is applied to adjust the accuracy of the system. To analyze the characteristic of all kind surfaces of automobile outer penal moulds and dies, classification of types of the surface、brim and ridge(or vale) area to be measured and processed has been established, resulting in one of the main processing functions of the laser processing system. According to different type of surfaces, a 2-D adaptive measuring method based on B?zier curve was developed; furthermore a 3-D adaptive measuring method based on Spline curve was also developed. According to the laser materials processing characteristics and data characteristics, necessary methods have been developed to generate processing tracks, they are explained in details. Measuring experiments and laser processing experiments were carried out to testify the above mentioned methods, which have been applied in the computer integrated and flexible laser processing system developed by the Institute of Mechanics, CAS.

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Based on the computer integrated and flexible laser processing system, develop the intelligent measuring sub-system. A novel model has been built to compensate the deviations of the main frame, a new-developed 3-D laser tracker system is applied to adjust the accuracy of the system. Analyzing the characteristic of all kinds of automobile dies, which is the main processing object of the laser processing system, classify the types of the surface and border needed to be measured and be processed. According to different types of surface and border, develop 2-D adaptive measuring method based on B?zier curve and 3-D adaptive measuring method based on spline curve. During the data processing, a new 3-D probe compensation method has been described in details. Some measuring experiments and laser processing experiments are carried out to testify the methods. All the methods have been applied in the computer integrated and flexible laser processing system invented by the Institute of Mechanics, CAS.

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A complete set of match calculation methods for optimum sizing of PV/wind hybrid system is presented. In this method, the more accurate and practical mathematic models for characterizing PV module, wind generator and battery are adopted; combining with hourly measured meteorologic data and load data, the performance of a PV/wind hybrid system is determined on a hourly basis; by fixing the capacity of wind generators, the whole year's LPSP (loss of power supply probability) values of PV/wind hybrid systems with different capacity of PV array and battery bank are calculated, then the trade-off curve between battery bank and PV array capacity is drawn for the given LPSP value; the optimum configuration which can meet the energy demand with the minimum cost can be found by drawing a tangent to the trade-off curve with the slope representing the relationship between cost of PV module and that of the battery. According to this match calculation method, a set of match calculation programs for optimum sizing of PV/wind hybrid systems have been developed. Applying these match calculation programs to an assumed PV/wind hybrid system to be installed at Waglan island of Hong Kong, the optimum configuration and its hourly, daily, monthly and yearly performances are given. (C) 2003 Elsevier Science Ltd. All rights reserved.