教学质量与多媒体应用效果的提升对策

多媒体教学以它丰富的媒体表现形式、强大的交互功能等优势,已然成为现代课堂教学上提高教学质量,培养学生创新意识的有效手段。本文就如何提高多媒体应用效果的同时,提升教学质量,展开研究,并提出一些可行的建议及解决方案。     

Petri net based formal analysis for multimedia conferencing services orchestration

Development of services that span over the Internet and Telecom networks is driving significant efforts towards the integrated of services offered by Telecom operators. Service-oriented communication (SOC) is a new trend in the industry to enable communication through a service-oriented architecture (SOA) and thereby package communications as services. In this paper, we firstly introduce the design and implementation for business process execution language (BPEL) based multimedia conferencing communication services orchestration, and mainly focus on the issue of guaranteeing the correctness of such applications, we presents a Petri net-based approach to analyzing the BPEL based multimedian conferencing communication services orchestration correctness and also a set of translation rules is proposed to transform BPEL processes into Petri nets. Especially, we define the correctness of multimedia conferencing services orchestration and address the verification method based on Petri nets. The algorithms and corresponding reliable issues have been proposed, such as the coverability tree for detecting flow safeness, the incidence matrix & state equation for finding reachable issues, and a transitive matrix for detecting a deadlock problem. With the Petri Net Markup Language (PNML) are introduced to transform a orchestrated services into a Petri net model, and providing an automated support for the formal analysis of their behavior. Finally, we give the conclusions.     

CMMB系统中的符号与时钟同步方案

提出一种基于中国移动多媒体广播(CMMB)系统的符号同步与时钟同步方案,其中,CMMB系统是基于正交频分复用(OFDM)实现的。为正确获得CMMB系统中OFDM符号的起始位置,并消除采样时钟偏差对系统的影响,将信标符号与循环前缀相结合,给出基于OFDM的符号同步方案,包括获取与跟踪2个阶段,以解决系统符号同步问题,同时利用OFDM符号中的离散导频对采样时钟频率偏差进行估计,取其均方误差作为验证标准,从而实现系统的时钟同步。仿真结果表明,该方案有效可行。     

一种IMS网络信令异常处理检测方法

针对IMS网络中被入侵或劫持的网络实体可能对信令消息做出恶意篡改等异常处理的问题,提出一种基于信令处理规则的IMS 网络信令异常处理检测方法.该方法基于建立的信令处理规则库,模拟实体对信令消息的正常处理并生成一条预处理消息,通过判断预处理消息与经过实体处理后的信令消息是否匹配,检测IMS网络中是否存在信令异常处理.实验结果表明,该方法对信令异常处理的检测率达到了100％.     

支持多种终端的多媒体展示中间件

为了规范多媒体业务开发,首先分析传统信息展示系统的弊端,在此基础上,提出基于中间件技术的多媒体展示中间件,重点讨论中间件的系统架构和核心模块实现。为了验证展示中间件的跨平台性,使用展示中间件的验证系统IMPS对其进行实验,通过数据分析证明了中间件在不同平台运行稳定可靠。     

Cross-media retrieval using query dependent search methods

The content-based cross-media retrieval is a new type of multimedia retrieval in which the media types of query examples and the returned results can be different. In order to learn the semantic correlations among multimedia objects of different modalities, the heterogeneous multimedia objects are analyzed in the form of multimedia document (MMD), which is a set of multimedia objects that are of different media types but carry the same semantics. We first construct an MMD semi-semantic graph (MMDSSG) by jointly analyzing the heterogeneous multimedia data. After that, cross-media indexing space (CMIS) is constructed. For each query, the optimal dimension of CMIS is automatically determined and the cross-media retrieval is performed on a per-query basis. By doing this, the most appropriate retrieval approach for each query is selected, i.e. different search methods are used for different queries. The query dependent search methods make cross-media retrieval performance not only accurate but also stable. We also propose different learning methods of relevance feedback (RF) to improve the performance. Experiment is encouraging and validates the proposed methods.     

Promoting social network awareness: A social network monitoring system

To increase communication and collaboration opportunities, members of a community must be aware of the social networks that exist within that community. This paper describes a social network monitoring system – the KIWI system – that enables users to register their interactions and visualize their social networks. The system was implemented in a distributed research community and the results have shown that KIWI facilitates collecting information about social interactions. Furthermore, the visualization of the social networks, given as feedback, appeared to have a positive impact on the group, augmenting their social network awareness.     

The effect of multiple scaffolding tools on students’ understanding,consideration of different perspectives,and misconceptions of a complex problem

This study investigated the effectiveness of multiple scaffolding tools in helping students understand a complex problem. In order to support students with this task, a multimedia learning environment was developed based on the cognitive flexibility theory (CFT) and scaffolding through computer-based tools. Seventy-nine 10th-grade students in an urban high school participated in this study. A quasi-experimental method was used to compare the effectiveness of different scaffolding tools within this learning environment. Scaffolding used in conjunction with CFT principles did not affect students’ ability to consider multiple perspectives or their numbers of misconceptions. On the other hand, scaffolding tools had varying effects on students’ problem understanding, and a significant interaction was found between the different scaffolding tools used. This study raised questions about the effectiveness of combining multiple scaffolding tools within a multimedia environment.     

Exploring relations among college students’ prior knowledge,implicit theories of intelligence,and self-regulated learning in a hypermedia environment

Researchers and educators continue to explore how to assist students in the acquisition of conceptual understanding of complex science topics. While hypermedia learning environments (HLEs) afford unique opportunities to display multiple representations of these often abstract topics, students who do not engage in self-regulated learning (SRL) with HLEs often fail to achieve conceptual understanding. There is a lack of research regarding how student characteristics, such as prior knowledge and students’ implicit theory of intelligence (ITI), interact with SRL to influence academic performance. In this study, structural equation modeling was used to investigate these issues. It was found that prior knowledge and ITI were related to SRL and performance, and that SRL acted as a benevolent moderator, enhancing the positive effects of prior knowledge upon learning, and diminishing the negative effects of having a maladaptive ITI.