Proficiency-Adapted Information Browsing and Filtering in Hypermedia Educational Systems

We present a framework for proficiency-adapted information browsing and filtering in educational hypermedia systems. In hyperdocuments, information is acquired by browsing through highly interconnected sets of information nodes. In order to find specific information, users follow links to nodes they judge to be relevant. In order to help users find relevant information and new learning material that match their levels of domain knowledge, we present a framework for adapting the information nodes, and the links leading to them, to the user's proficiency in the subject matter. Such a proficiency-adapted, user-centered educational environment is intended to enhance learning. We believe that learning in educational hypertext-based applications cannot be reduced to traversing a static information space. Navigating through any space, be it a physical or an information space, normally requires that users have a prior degree of proficiency in the domain knowledge. Learning is an evolving dynamic process through which users progress from a situation of unfamiliarity to one of mastery of a knowledge corpus. Therefore, we propose a model of proficiency-adapted learning and information browsing in which the presented choices (links and the textual context of links) are selected based on the user's knowledge state. Ultimately, such an adaptive course not only guides the learning process of the student, but it gradually transforms itself into a reference guide. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Fuzzy-Based Approach to Stereotype Selection in Hypermedia

This paper presents a stereotype-based user model for adaptive hypermedia systems. We use a suitable algebraic fuzzy structure which can adequately reflect some features of the user in the model, and apply this model to adapt the navigation and the content of hypermedia nodes to the user's needs. The model includes temporal representations of the user and approximates every real user by a set of stereotypes, from which the one realizing the best approximation can always be extracted. The set of stereotypes is the support set of the structure and the operations defined therein may be supplied with adequate semantics which allow for the selection of the stereotype.     

Personalizing the Interaction in a Web-based Educational Hypermedia System: the case of INSPIRE

In this paper we present an Adaptive Educational Hypermedia prototype, named INSPIRE. The approach employed in INSPIRE emphasizes the fact that learners perceive and process information in very different ways, and integrates ideas from theories of instructional design and learning styles. Our aim is to make a shift towards a more 'learning-focused' paradigm of instruction by providing a sequence of authentic and meaningful tasks that matches learner' preferred way of studying. INSPIRE, throughout its interaction with the learner, dynamically generates learner-tailored lessons that gradually lead to the accomplishment of learner's learning goals. It supports several levels of adaptation: from full system-control to full learner-control, and offers learners the option to decide on the level of adaptation of the system by intervening in different stages of the lesson generation process and formulating the lesson contents and presentation. Both the adaptive and adaptable behavior of INSPIRE are guided by the learner model which provides information about the learner, such as knowledge level on the domain concepts and learning style. The learner model is exploited in multiple ways: curriculum sequencing, adaptive navigation support, adaptive presentation, and supports system's adaptable behavior. An empirical study has been performed to evaluate the adaptation framework and assess learners' attitudes towards the proposed instructional design.     

Collaborative Technology in the Classroom: A Review of the GSS Research and a Research Framework

Over the past several years, a number of research studies have investigated the application of group support system (GSS) technology to the classroom. The purpose of this paper is twofold: (1) to summarize and assess what has been learned from this emerging body of research, and (2) to draw on the GSS and cooperative learning literatures to construct a framework to guide future studies. The review of research studies reported in this paper focuses on comparative studies investigating the synchronous GSS classroom environment. While research findings regarding the impacts of GSS on learning performance are somewhat mixed, early indications are encouraging and suggest that GSS may have a positive impact under certain situations. A framework based on the GSS and cooperative learning research is introduced that identifies the contextual, group process, and outcome factors that researchers may wish to consider when designing and interpreting future research studies in this area.     

一种新的划分下钢结构节点图自动标注算法

文章介绍一种钢结构中节点图自动标注算法。首先介绍相关的背景知识,然后介绍节点图自动标注的关键技术及难点,接着提出对关键技术及难点的解决方案,是一种以符合工程需求为首要条件的基于区域划分的方案,最后给出算法实现的条件及实现过程。     

Virtual reality simulations and animations in a web-based interactive manufacturing engineering module

This paper presents a web-based interactive teaching package that provides a comprehensive and conducive yet dynamic and interactive environment for a module on automated machine tools in the Manufacturing Division at the National University of Singapore. The use of Internet technologies in this teaching tool makes it possible to conjure visualisations that cannot be achieved using traditional teaching materials such as transparencies. Virtual reality simulations and animations were developed and appropriately placed in the teaching materials to enhance the student understanding of complex concepts. This is especially useful in teaching automated machine tools, which deals primarily with the numerical control (NC) of the motions of automated machine tools. These virtual reality simulations and animations provide the capability of training students in NC programming and operations without the need to work on actual NC machines in the laboratory. The simulations are suitably placed in the package to engage the students and enhance their concentration, while at the same time generate interactions. Customised question types were also designed and implemented with a tutorial monitoring application.     

商品化CAD软件中基于二维视图的三维重建模块的设计与实现

探索出一种符合工程技术人员思维方式的基于二维视图的三维重建方法,并在商品化软件Solid2000中作为一个模块实现．解决了三维重建中DWG文件的数据转换、视图分离及视图的BOX显示、特征生成、重建结果验证、曲线拟合等问题．该模块以交互和自动结合的方式进行,设计完整实用,充分利用了二维视图信息,提高了三维建模的速度．     

The influence of collaboration styles to children’s cognitive performance in digital problem-solving game “William Adventure”: A comparative case study

Since a large variety of digital games have been used in many fields for educational purposes, their real functions in learning have caught much attention as well. This study first defines learning characteristics of problem-solving digital games and their corresponding cognitive levels, then designs and develops a problem-solving game in accordance to the criteria. Tasks in the game context are inter-related to each other so that players need to critically and creatively think about problem solutions. Learners’ task analyses are performed to observe four elementary learners’ gaming paths, behaviors and cognitive activities, individually and collaboratively. System documentation, video recording, researcher observation, and interviews are conducted to analyze learners’ learning strategies and their cognitive performance during the gaming process.     

Learning science in a virtual reality application: The impacts of animated-virtual actors’ visual complexity

As the technology in computer graphics advances, Animated-Virtual Actors (AVAs) in Virtual Reality (VR) applications become increasingly rich and complex. Cognitive Theory of Multimedia Learning (CTML) suggests that complex visual materials could hinder novice learners from attending to the lesson properly. On the other hand, previous studies have shown that visual complexity correlates with presence and may increase the perceived affective quality of the virtual world, towards an optimal experience or flow. Increasing these in VR applications may promote enjoyment and higher cognitive engagement for better learning outcomes. While visually complex materials could be motivating and pleasing to attend to, would they affect learning adversely? We developed a series of VR presentations to teach second-year psychology students about the navigational behaviour of Cataglyphis ants with flat, cartoon, or lifelike AVAs. To assess learning outcomes, we used Program Ratings, which measured perception of learning and perceived difficulty, and retention and transfer tests. The results from 200 students did not reveal any significant differences in presence, perceived affective quality, or learning outcomes as a function of the AVA’s visual complexity. While the results showed positive correlations between presence, perceived affective quality and perception of learning, none of these correlates with perceived difficulty, retention, or transfer scores. Nevertheless, our simulation produced significant improvements on retention and transfer scores in all conditions. We discuss possible explanations and future research directions.     

A task-centered approach for user modeling in a hypermedia office documentation system

The development of user-adaptive systems is of increasing importance for industrial applications. User modeling emerged from the need to represent in the system knowledge about the user in order to allow informed decisions on how to adapt to match the user's needs. Most of the research in this field, however, has been theoretical, top-down. Our approach, in contrast, was driven by the needs of the application and shows features of bottom-up, user-centered design.We have implemented a user modeling component supporting a task-based interface to a hypermedia information system for hospitals and tested it under realistic conditions. A new architecture for user modeling has been developed which focuses on the tasks performed by users. It allows adaptive browsing support for users with different level of experience, and a level of adaptability. The requirements analysis shows that the differences in the information needs of users with different levels of experience are not only quantitative, but qualitative. Experienced users are not only able to cope with a wider browsing space, but sometimes prefer to organize their search in a different way. That is why the user model and the interface of the system are designed to support a smooth transition in the access options provided to novice users and to expert users.     

基于规则的建筑结构图钢筋用量自动识别系统

传统的手工建筑工程量统计方法不仅费时而且容易出错,利用计算机自动完成工程量统计工作则可以很好地解决这一问题.介绍了一个基于规则的建筑结构图自动识别系统(automatic interpretation of structure drawings,简称AISD).该系统以矢量化后的电子图档为基础,通过总结建筑工程图结构特征及绘图规则,自动分析图中的各种图形元素、符号以及其关系,理解各种部件信息,并加以综合,以获取正确的建筑工程钢筋用量.通过对工程图的特征进行详细的研究,总结出一套基于规则的适应不同类型工程图     

A comprehensive approach to horizontal class fragmentation in a Distributed Object Based System

Optimal application performance on a Distributed Object Based System (DOBS) requires class fragmentation and the development of allocation schemes to place fragments at distributed sites so data transfer is minimized. Fragmentation enhances application performance by reducing the amount of irrelevant data accessed and the amount of data transferred unnecessarily between distributed sites. Algorithms for effecting horizontal and vertical fragmentation ofrelations exist, but fragmentation techniques for class objects in a distributed object based system are yet to appear in the literature. This paper first reviews a taxonomy of the fragmentation problem in a distributed object base. The paper then contributes by presenting a comprehensive set of algorithms for horizontally fragmenting the four realizable class models on the taxonomy. The fundamental approach is top-down, where the entity of fragmentation is the class object. Our approach consists of first generating primary horizontal fragments of a class based on only applications accessing this class, and secondly generating derived horizontal fragments of the class arising from primary fragments of its subclasses, its complex attributes (contained classes), and/or its complex methods classes. Finally, we combine the sets of primary and derived fragments of each class to produce the best possible fragments. Thus, these algorithms account for inheritance and class composition hierarchies as well as method nesting among objects, and are shown to be polynomial time. Recommended by: Patrick Valduriez     

一种嵌信式微机数据采集系统的实现

主要讨论一个嵌入式微处理机数据采集系统的软／硬件设计方案。     

A New Low Cost System for Autonomous Robot Heading and Position Localization in a Closed Area

A low cost system for the localization of mobile indoor robots is presented. The system is composed of an emitter located on a wall and a receptor on top of the robot. The emitter is a laser pointer acting like a beacon, and the receptor is a cylinder made out of 32 independent photovoltaic cells. The robot's position and orientation are obtained from the moments when the laser crosses each cell.     

提升风洞测力数据采集系统电磁兼容能力初步研究

随着风洞试验技术的不断进步,风洞现场的电磁设备越来越多,电磁干扰对风洞测力试验数据的准确性可靠性带来了挑战。研究风洞测力数据采集系统电磁兼容性问题是有效解决电磁干扰保障测力试验顺利进行的前提,是提高风洞试验精度、改善测量数据质量、提升试验能力的重要手段。文章以某主力风洞测力数据采集系统为研究对象,从电磁干扰途径和自身电磁敏感度两个方面对采集系统进行了电磁兼容分析,并结合分析结果通过采取合理有效的电磁兼容措施,提高了风洞测力数据采集系统抗电磁干扰能力,确保了测力试验数据质量的可靠性和稳定性。     

Using Hybrid Automata to Support Human Factors Analysis in a Critical System

A characteristic that many emerging technologies and interaction techniques have in common is a shift towards tighter coupling between human and computer. In addition to traditional discrete interaction, more continuous interaction techniques, such as gesture recognition, haptic feedback and animation, play an increasingly important role. Additionally, many supervisory control systems (such as flight deck systems) already have a strong continuous element. The complexity of these systems and the need for rigorous analysis of the human factors involved in their operation leads us to examine formal and possibly automated support for their analysis. The fact that these systems have important temporal aspects and potentially involve continuous variables, besides discrete events, motivates the application of hybrid systems modelling, which has the expressive power to encompass these issues. Essentially, we are concerned with human-factors related questions whose answers are dependent on interactions between the user and a complex, dynamic system.In this paper we explore the use of hybrid automata, a formalism for hybrid systems, for the specification and analysis of interactive systems. To illustrate the approach we apply it to the analysis of an existing flight deck instrument for monitoring and controlling the hydraulics subsystem.     

A Case Study on Applying a Tool for Automated System Analysis Based on Modular Specifications Written in TRIO

An effective means for analyzing and reasoning on software systems is to use formal specifications to simulate their execution. The simulation traces can be used for specification testing and reused for functional testing of the system later in the development process. It is widely acknowledged that, to deal with the complexity of industrial-size systems, specifications must be structured into modules providing abstraction mechanisms and clear interfaces. In our past work, we defined and implemented a method for simulating specifications written in the TRIO temporal logic language, and applied it to functional testing of time-critical industrial systems. In the present paper, we report on a case study with a tool that analyzes TRIO specifications by taking advantage of their modular structure, so as to overcome the well-known state-explosion problem and make the proposed method really scalable. We discuss the fundamental operations and the algorithms on which the tool is based. Then, we illustrate its use in a realistic case study, inspired from an industrial application. Finally, we comment on the overall results in terms of usability of the tool and effectiveness of the approach, and we outline future improvements.     

工作流管理系统中一种概率性分析和调整时间约束的方法

时间管理是工作流管理系统应提供的重要功能,其中一个关键问题是分析时间约束的可行性,并调整时间约束以避免可能出现的违反.然而,在高度不确定的工作流环境下,传统定性的时间约束分析结果过于严格.因此,提出概率时间约束工作流网来描述时间约束下的工作流流程.基于该网提出一种方法,以随机的形式分析活动满足时间约束的概率.该概率能帮助流程管理者灵活地分析时间约束的可行性,进一步为时间约束调整提供精确的指导.此外,用一个实际工作流管理系统中的例子验证工作的有效性.     

一种新的全镇定控制器的参数设计法研究

Youla参数化方法广泛应用于控制系统的分析和设计;此方法使得系统闭环稳定的全部的镇定控制器均以一个稳定传递函数作为待定参数来表达;建立另外一种不同的参数化方法,这种方法尤其适用于主动振动控制系统:它不仅参数化所有镇定控制器,同时能够给控制性能变量以非常直观的几何图形解释;讨论这种新方法的特性及其设计,并将该设计方法应用于一个三自由度的主动振动隔离系统中,仿真结果表明,所提出的方法可以有效地达到主动振动隔离的设计目的。