数字互动电视终端改造方案的研究

对当前数字电视网络双向改造的几种方案进行分析比较,以最小的代价来实现数字电视网络双向改造,同时对在改造过程中遇到的问题提出解决办法。该研究成果将能为广电以后顺利开展数字电视互动业务提供较好的参考价值和实际意义。     

分布式仿真多分辨率建模方法及一致性维护

在分布式仿真中,同一实体的多个分辨率模型并发以及不同实体的各个分辫率模型之间的交互会导致数据表现不一致的问题。在分析现有多分辨率建模方法的基础上,提出了适应分布式仿真环境的不同分辨率模型的树状结构建模方法,其主要由聚合级实体模型和平台级实体模型组成。为解决树状结构建模方法中不同分辫率模型的数据表现不一致问题,将不同分辨率模型间的交互看成分布式数据库中的事务,由此提出了一个嵌套两段式提交协议算法来有效解决不同分辨率模型的一致性维护问题。     

HMP在呼叫中心系统中的应用

随着通信技术、计算机技术和互联网技术不断的发展融合,产生了一种全新的CTI(Computer Telecommunication Integration)技术,利用CTI技术可以把语音和数据传输相结合,充分发挥各自的优点,而通信增值服务是在CTI技术的基础上迅速发展的一种全新增值服务方式,其中最重要的应用就是呼叫中心系统的发展,是未来通信领域中增值服务的发展趋势,具有很大的发展商机和研究价值。     

交互式远程教学系统的设计与实现

随着网络化技术的发展,基于网络的远程教学活动及教学系统逐渐成为学校教育的有效辅助手段。本文从远程教学系统的需求出发、分析了系统的结构和各组成部分的功能。重点介绍了考试管理模块的功能,以及该模块中部分功能的实现。     

AGAPIA v0.1: A Programming Language for Interactive Systems and Its Typing System

A model (consisting of rv-systems), a core programming language (for developing rv-programs), several specification and analysis techniques appropriate for modeling, programming and reasoning about interactive computing systems have been recently introduced by Stefanescu using register machines and space-time duality, see [Stefanescu, G. Interactive systems with registers and voices. Fundamenta Informaticae 73 (2006), 285–306. (Early draft, School of Computing, National University of Singapore, July 2004.)]. After that, Dragoi and Stefanescu have developed structured programming techniques for rv-systems and their verification, see, e.g., [Dragoi, C., and G. Stefanescu. Structured programming for interactive rv-systems. Institute of Mathematics of the Romanian Academy, IMAR Preprint 9/2006, Bucharest 2006. Dragoi, C., and G. Stefanescu. Towards a Hoare-like logic for structured rv-programs. Institute of Mathematics of the Romanian Academy, IMAR Preprint 10/2006, Bucharest, 2006. Dragoi, C., and G. Stefanescu. Implementation and verification of ring termination detection protocols using structured rv-programs. Annals of University of Bucharest, Mathematics-Informatics Series, 55 (2006), 129–138. Dragoi, C., and G. Stefanescu. Structured interactive programs with registers and voices and their verification. Draft, Bucharest, January 2007. Dragoi, C., and G. Stefanescu. On compiling structured interactive programs with registers and voices. In: “Proc. SOFSEM 2008,” 259–270. LNCS 4910, Springer, 2008.].In the present paper a kernel programming language AGAPIA v0.1 for interactive systems is introduced. The language contains definitions for complex spatial and temporal data, arithmetic and boolean expressions, modules, and while-programming statements with their temporal, spatial, and spatio-temporal versions. In AGAPIA v0.1 one can write programs for open processes located at various sites and having their temporal windows of adequate reaction to the environment. The main technical part of the paper describes a typing system for AGAPIA v0.1 programs.     

Educational virtual environments: design rationale and architecture

The use of collaborative virtual environments in e-learning is one of the most promising uses of virtual reality technology. While much research has been done in the area of networked virtual environments corresponding to the sharing of events, very little research has been done on specific services and functionality. However both the requirements and the kind of the offered services affect significantly the design of a system. In this paper we present the design and implementation of a platform suitable for educational virtual environments, which are collaborative virtual environments aiming at offering collaborative e-learning services to the users. Apart from the platform itself, we present the technological choices, and a new method for sharing virtual environments. Furthermore, we present an e-learning environment to support e-learning services using collaborative virtual environments from both the technical and functional point of view, along with the end-user evaluation results.

A Unified Subdivision Scheme for Polygonal Modeling

Subdivision rules have traditionally been designed to generate smooth surfaces from polygonal meshes. In this paper we propose to employ subdivision rules as a polygonal modeling tool, specifically to add additional level of detail to meshes. However, existing subdivision schemes have several undesirable properties making them ill suited for polygonal modeling. In this paper we propose a general set of subdivision rules which provides users with more control over the subdivision process. Most existing subdivision schemes are special cases. In particular, we provide subdivision rules which blend approximating spline based schemes with interpolatory ones. Also, we generalize subdivision to allow any number of refinements to be performed in a single step.     

Valence-Driven Connectivity Encoding for 3D Meshes

In this paper, we propose a valence-driven, single-resolution encoding technique for lossless compression of triangle mesh connectivity. Building upon a valence-based approach pioneered by Touma and Gotsman²² , we design a new valence-driven conquest for arbitrary meshes that always guarantees smaller compression rates than the original method. Furthermore, we provide a novel theoretical entropy study of our technique, hinting the optimality of the valence-driven approach. Finally, we demonstrate the practical efficiency of this approach (in agreement with the theoretical prediction) on a series of test meshes, resulting in the lowest compression ratios published so far, for both irregular and regular meshes, small or large.     

Windows NT的安全问题

本文从ＷｉｎｄｏｗｓＮＴ的交式登录过程、Ｗｉｎ３２ＷｉｎＬｏｇｏｎ进程进行用户信息登录、管理员利用域用户管理器用户建立帐号及设置安全属性、设置用户权限、目录访问权限类型、文件系统和打印机的安全性能、设置访问许可权、ＮＴＦＳ目录级别权限、对服务器系统进行物理性能方面的设置、审计、设置登录标语、注册表面的安全性,安全保障的几个方面、ＷｉｎｄｏｗｓＮＴ中的缺陷等诸多方面讨论了ＷｉｎｄｏｗｓＮＴ的安全问题     

What holds in a context?

In order to establish that [A] = [B] follows from a set of assumptions often one provesA =B and then invokes the principle of substitution of equals for equals. It has been observed that in the ancillary proof ofA =B one is allowed to use, in addition to those assumptions of which are free for , certain (open) sentencesP which may not be part of and may not follow from , but are related to the context . We show that in an appropriate formal system there is a closed form solution to the problem of determining precisely what sentencesP can be used. We say that those sentenceshold in the context under the set of assumptions . We suggest how the solution could be exploited in an interactive theorem prover.