基于Linux内核高速IP网络测量器的研究

With the rapid development in network technology field, the network IP packet measuring technology has become basis of the large-scale network's behavior analysis. The paper analyzes the function and performance requirement to high-speed network measure, and the construction of Linux's network subsystem. Based on these, the paper shows a proper framework design for a high-speed meter on Linux kernel and gives out an optimized quick sort arithmetic design, which gets good balance between space and time complication. At the end of the paper, a meter archetype according to the design is introduced. And any more there are several experiment data and figures of it under high-speed CERNET network environment, which show the correctness of the framework design and the high performance the arithmetic brines.     

Logical Object as a Basis of Knowledge Based Systems

This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs).LKO combines logic programming and object-oriented programming paradigms,where objects are viewed as abstractions with states,constraints,behaviors and inheritance.The operational semantics defined in the style of natural semantics is simple and clear.A hybrid knowledge representation amalgamating rule,frame,semantic network and blackboard is available for both most structured and flat knowledge.The management of knowledge bases has been formally specified.Accordingly,LKO is well suited for the formal representation of knowledge and requirements of KBSs.Based on the framework,verification techniques are also explored to enhance the analysis of requirement specifications and the validation of KBSs.In addition,LKO provides a methodology for the development of KBSs,applying the concepts of rapid prototyping and top-down design to deal with changing and incomplete requirements,and to provide multiple abstract models of the domain,where formal methods might be used at each abstract level.     

Managing Data-Objects in Dynamically Reconfigurable Caches

The widening gap between processor and memory speeds makes cache an important issue in the computer system design.Compared with work set of programs,cache resource is often rare.Therefore,it is very important for a computer system to use cache efficiently.Toward a dynamically reconfigurable cache proposed recently,DOOC(Data-Object Oriented Cache),this paper proposes a quantitative framework for analyzing the cache requirement of data-objects, which includes cache capacity,block size,associativity and coh...     

Secure System Modeling: Integrating Security Attacks with Statecharts

Software security is becoming an important concern as software applications are increasingly depending on the Internet, an untrustworthy computing environment. Vulnerabilities due to design errors, inconsistencies, incompleteness, and missing constraints in software design can be wrongly exploited by security attacks. Software functionality and security, however, are often handled separately in the development process. Software is designed with the mindset of its functionalities and cost, where the focus is mainly on the operational behavior. Security concerns, on the other hand, are often described in an imprecise way and open to subjective interpretations. This paper presents a threat driven approach that improves on the quality of software through the realization of a more secure model. The approach introduces systematic transformation rules and integration steps for integrating attack tree representations into statechart-based functional models. Through the focus on the behavior of an attack from the perspective of the system behavior, software engineers can clearly define and understand security concerns as software is designed. Security analysis and threat identification are then applied to the integrated model in order to identify and mitigate vulnerabilities at the design level.     

应用设计模式设计可移植的、可扩充、简单灵活的嵌入式GUIToolkit

The environments in which embedded software run are different in that they may run on different processors, have different input devices, and display graphics on a variety of video devices. In addition, it usually has limited computing and storing capability which require embedded GUI toolkit simple and flexible. According to the characteristics and the requirements of embedded environment, this story shows an embedded GUI toolkit and some design concerns, that is, applying design patters to design embedded GUI Toolkit to achieve high portability,extensibility and flexibility.     

Efficient Incremental Maintenance for Distributive and Non-Distributive Aggregate Functions

Data cube pre-computation is an important concept for supporting OLAP （Online Analytical Processing） and has been studied extensively. It is often not feasible to compute a complete data cube due to the huge storage requirement. Recently proposed quotient cube addressed this issue through a partitioning method that groups cube cells into equivalence partitions. Such an approach not only is useful for distributive aggregate functions such as SUM but also can be applied to the maintenance of holistic aggregate functions like MEDIAN which will require the storage of a set of tuples for each equivalence class. Unfortunately, as changes are made to the data sources, maintaining the quotient cube is non-trivial since the partitioning of the cube cells must also be updated. In this paper, the authors design incremental algorithms to update a quotient cube efficiently for both SUM and MEDIAN aggregate functions. For the aggregate function SUM, concepts are borrowed from the principle of Galois Lattice to develop CPU-efficient algorithms to update a quotient cube. For the aggregate function MEDIAN, the concept of a pseudo class is introduced to further reduce the size of the quotient cube, Coupled with a novel sliding window technique, an efficient algorithm is developed for maintaining a MEDIAN quotient cube that takes up reasonably small storage space. Performance study shows that the proposed algorithms are efficient and scalable over large databases.     

GaiaDoc： A Tool Focused on Business Requirements for Code Documentation with a CMMI Compliant and RUP Based on Requirement Flow

Aiming to fill a gap in traditional methods of source code documentation, which focus mainly on the API （application programming interface） documentation for other programmers, this article presents a new approach for business requirements, mapping them through a set of annotations. These annotations, in turn, are interpreted by the GaiaDoc tool, which is specified in this paper and is able to generate documentation in form of use case specifications in a language and format easily understandable by the project stakeholders. Along with the GaiaDoc tool proposal, a RUP （rational unified process） based requirements flow is developed to fit with its needs and it is validated through CMMI （capability maturity model integration） requirement process areas and a case study of the proposed methodology＇s application is presented before the final considerations.     

Computational Problem Solving in Spatial Substrates -- A Cognitive Systems Engineering Approach

The ability to perform spatial tasks is crucial for everyday life and of great importance to cognitive agents such as humans, animals, and autonomous robots. A common artificial intelligence approach to accomplish spatial tasks is to represent spatial configurations and tasks in form of detailed knowledge about various aspects of space and time. Suitable algorithms then use the representations to compute solutions to spatial problems. In comparison, natural embodied and situated agents often solve spatial tasks without detailed knowledge about geometric, topological, or mechanical laws; they directly relate actions to effects that are due to spatio-temporal affordances in their bodies and environments. Accordingly, we propose a paradigm that makes the spatio-temporal substrate an integral part of the engine that drives spatial problem solving. We argue that spatial and temporal structures in body and environment can substantially support (and even replace) reasoning effort in computational processes: physical manipulation and perception in spatial environments substitute formal computation. While the approach is well known – for example, we employ diagrams as spatial substrate for geometric problem solving and maps for wayfinding – the underlying principle has not been systematically investigated or formally analyzed as a paradigm of cognitive processing. Topology, distance, and orientation constraints are all integrated and interdependent in truly 2- or 3-dimensional space. Exploiting this fact may not only help overcome the need for acquiring detailed knowledge about the interrelationships between different aspects of space; it also can point to a way of avoiding exploding computational complexity that occurs when we deal with these aspects of space in complex real-world scenarios. Our approach employs affordance-based object-level problem solving to complement knowledge-level formal approaches. We will assess strengths and weaknesses of the new cognitive systems paradigm.     

Reduction of Unneccessary Dotted Rules in the Earley—Algorithm

With the high developed hardware from the PC‘s today,there arise possibilities to implement programming environments on such kind of computers.To rduces the amount of calculaiton time and required memory space from implemented algorithms.new optimization approaches in the algorithm design are demanded.The purpose of this work is to explore and analyse possibilities to reduce the required memory space through elimination of superfluonus grammar rules created during the process of recognition.     

Universal triple I fuzzy reasoning algorithm of function model based on quotient space

Aiming at the deficiencies of analysis capacity from different levels and fuzzy treating method in product function modeling of conceptual design,the theory of quotient space and universal triple I fuzzy reasoning method are introduced,and then the function modeling algorithm based on the universal triple I fuzzy reasoning method is proposed.Firstly,the product function granular model based on the quotient space theory is built,with its function granular representation and computing rules defined at the same time.Secondly,in order to quickly achieve function granular model from function requirement,the function modeling method based on universal triple I fuzzy reasoning is put forward.Within the fuzzy reasoning of universal triple I method,the small-distance-activating method is proposed as the kernel of fuzzy reasoning;how to change function requirements to fuzzy ones,fuzzy computing methods,and strategy of fuzzy reasoning are respectively investigated as well;the function modeling algorithm based on the universal triple I fuzzy reasoning method is achieved.Lastly,the validity of the function granular model and function modeling algorithm is validated.Through our method,the reasonable function granular model can be quickly achieved from function requirements,and the fuzzy character of conceptual design can be well handled,which greatly improves conceptual design.     

一种基于AOP的企业应用开发技术

面向方面的编程(Aspect-OrientedProgramming,AOP)是一种新的编程技术,它弥补了面向对象的编程(Object-OrientedProgramming,OOP)在跨越模块行为上的不足。AOP引进了Aspect,它将影响多个类的行为封装到一个可重用模块中,它允许程序员对横切关注点(crosscuttingconcerns,即跨越典型职责界限的行为,例如日志记录)进行模块化,从而消除了OOP引起的代码混乱和分散问题,增强了系统的可维护性和代码的重用性。该文首先分析了AOP与OOP的比较,然后给出了AOP的原理和AOP的JBoss实现,最后介绍AOP在设计模式中的应用,并说明了使用它所带来的设计益处以及在应用AOP中应注意的问题。     

基于AOP的Web系统事务管理的应用研究

面向方面的程序设计（Aspect—Oriented Programming,AOP）是在继承OOP基础之上进行改进而来的一种创新的软件设计方法,通过引入方面概念,将应用程序中的核心业务逻辑同其提供支持的通用服务分离开来,从而降低代码之间的耦合度,增加程序的灵活性和可重用性。通过简介AOP在事务处理中的应用,介绍了Spring框架和AOP相结合的事务处理方法。通过采用Spring的AOP框架,使系统的核心业务逻辑和事务管理逻辑分开,从而系统的藕合性大大降低且易于扩展,面向方面编程提高了系统的模块性。     

一种基于组件的aspect-oriented编程框架

面向方面的编程(AOP:aspect-oriented programming)是一种新的编程技术.它引进了aspect,将影响多个模块的行为封装到一个可重用模块中,允许程序员对横切(crosscutting concerns)进行模块化,从而消除了面向对象编程(OOP:object-oriented programming)引起的代码混乱和分散问题.本文讨论了在服务体模型上实现的一种aspect-oriented编程框架.这个编程框架使用aspect组件,定义了对OOP语言的扩展,可方便将模块化的aspect代码扩展到源程序中,解决了OOP模型在这方面的不足.     

从面向方面程序设计的定义到面向方面程序设计语言

目前无论在学术界还是工业界,很多人士简单地将面向方面程序设计理解为模块化横切关注点,狭隘地认为 面向方面程序设计构建在面向对象程序设计之上,是面向对象程序设计的扩展、有效的补充等。回顾了面向方面程序 设计的定义,分析了面向方面程序设计区别于其它程序设计方法的本质特征,并形式化了定义中的量化语句与方面, 给出了量化语句与方面的语义。重申了面向方面程序设计的本质特性是Quantification与()bliviousncss,模块化横切 关注点只是其带来的一个好处。同时指出了面向方面程序设计是一种新型的程序设计范式,独立于面向对象等其它 程序设计方法。并且,基于此定义,给出了面向方面程序设计语言需满足的最小条件集,并比较了主流的面向方面程 序设计语言,探讨了这些语言在面向方面程序设计理念上的差异。     

面向方面的编程的研究与实现

面向方面的编程(AOP）是一种新的编程技术,它弥补了面向对象的编程(OOP)在跨越模块行为上的不足。 AOP 引进了Aspect,它将影响多个类的行为封装到一个可重用模块中,它允许程序员对横切关注点进行模块化,从而消除了OOP引起的代码混乱和分散问题,增强了系统的可维护性和代码的重用性。首先进行了AOP与OOP的比较,给出了AOP的原理和AOP的JBoss实现,最后介绍AOP在设计模式中的应用,并说明了使用它所带来的设计益处以及在应用AOP中应注意的问题。     

基于本体和多Agent的面向任务协同编程

针对面向对象编程与面向方面编程存在的问题,提出一种基于本体和多Agent的面向任务协同编程方法,给出任务分解原则、任务描述方法及编程的9个阶段。通过实例验证该方法可以提高目标软件系统的模块化程度,使目标软件系统易于实现、理解、演化和复用。     

在AOP中使用标注改进日志功能的实现

面向方面编程(AOP)可避免横切关注点对核心代码的不良影响,但AOP中的方法签名匹配模式难以精确表达系统中的横切点,使得在大中型系统中直接使用连接点匹配方式捕获某些横切点,同样会降低系统的可读性和模块化。该文以日志功能为例,研究如何使用标注来辅助AspectJ改进与日志功能相关的横切点定义,从而改善代码的可阅读性,提高程序的可维护性,并实现日志内容的可配置性。     

基于AOP的信息管理系统的研究与实现

面向对象的编程OOP（Object Oriented Programming）能够有效地解决面向过程语言的缺陷,现有的软件项目大都采用面向对象的编程范型。但是OOP不能解决由于横切属性带来的代码混乱和代码分散等诸多问题,导致系统的可读性和复用性差,因此引入了面向方面的编程AOP（Aspect—Oriented Programming）思想。该编程思想可使开发者有效地将业务关注点与横切关注点分离,解决OOP的难题。介绍了AOP技术中较成熟的语言——AspectJ及其相关概念,通过一个信息管理系统,展示AOP技术在处理横切关注点时发挥的优势。     

Tool-Supported Refactoring of Existing Object-Oriented Code into Aspects

Aspect-oriented programming (AOP) provides mechanisms for the separation of crosscutting concerns - functionalities scattered through the system and tangled with the base code. Existing systems are a natural testbed for the AOP approach since they often contain several crosscutting concerns which could not be modularized using traditional programming constructs. This paper presents an automated approach to the problem of migrating systems developed according to the object-oriented programming (OOP) paradigm into aspect-oriented programming (AOP). A simple set of six refactorings has been defined to transform OOP to AOP and has been implemented in the AOP-migrator tool, an Eclipse plug-in. A set of enabling transformations from OOP to OOP complement the initial set of refactorings. The paper presents the results of four case studies, which use the approach to migrate selected crosscutting concerns from medium-sized Java programs (in the range of 10K to 40K lines of code) into equivalent programs in AspectJ. The case study results show the feasibility of the migration and indicate the importance of the enabling transformations as a preprocessing step     

基于AOP的程序状态可视化方法研究与实现

论述了面向方面的编程（AOP）概念及其在处理横切关注点方面的优势，研究了其在程序状态可视化方面的应用，并利用AOP技术实现了一个表达式求值时的程序状态可视化的实例。程序状态可视化功能常常表现为一种横切关注点，相比利用面向对象的编程（OOP）来实现程序状态可视化功能，AOP技术提供了一种更加松耦合且更具模块性的实现方式。