分布式网络机器人的设计与实现

为了改善网络机器人的爬行性能以及提高系统体系结构的通用性,提出了基于Web Service的新型分布式网络机器人体系架构.分析了分布式网络机器人软件中的关键数据操作,并将这些功能封装在Web Service中,基于Web向网络机器人客户结点提供统一的数据服务,降低了网络机器人爬行客户端对网络环境的依赖性.设计了分布式爬行所需的均衡负载、URL队列操纵和网页消重等算法,实现了分布式网络机器人软件原型.实验结果表明,该原型的性能明显优于单机模式下的网络爬行,且网页消重、均衡负载算法是可行的.     

基于WinXP的实时控制在某舵机电动缸加载中的研究和应用

以Windows XP为系统平台,采用双核计算机,实现了对电动缸输出载荷的实时控制,提出了Windows XP下实时控制的具体实现方法和对其实时性能的要求。经多次试验验证,介绍的方案在实时控制方面,运行稳定、结构简单、成本低廉,具有广泛应用前景。     

多型号变加载磨合试验装置测控系统研究

针对多型号某传动机构的变加载磨合试验需求,研究了变加载磨合试验的相关技术,给出了一种双路传动链的磨合试验装置的构建及其实现方法。测控系统采用主从式控制模式,主机为工控机辅以多功能数据采集卡,用于磨合作业的调度、数据处理及人机交互等;从机为西门子Simotion D410运动控制系统,通过TCP/IP通信方式接收主机的数据指令,完成对磨合作业运动任务的控制。     

Integrating cognitive load theory and concepts of human–computer interaction

With the continually increasing complexity of e-learning environments, there is a need for integrating concepts of cognitive load theory (CLT) with concepts of human–computer interaction (HCI). Basic concepts of both fields were reviewed and contrasted. A literature review was conducted within the literature database “The Guide to Computing Literature,” searching for “cognitive load theory” and “Sweller.” Sixty-five publications contained “cognitive load” in their titles or abstracts. Each publication was checked to see whether it contained the concepts of intrinsic, extraneous, or germane cognitive load. The review showed that CLT concepts have been adopted in HCI. However, the concept of germane cognitive load has attracted less attention up to the present time. Two conceptual models are proposed. The first model divides extraneous cognitive load into load induced by the instructional design and load caused by software usage. The model clarifies the focus of traditional usability principles and of existing instructional design principles derived from CLT. The second model fits CLT concepts into the basic components of user-centered design. The concept of germane cognitive load illustrates that an increase of cognitive load can be desirable when designing e-learning environments. Areas for future interdisciplinary research are sketched.     

基于覆盖网络的海上信息栅格无线传输系统研究

文章在通信资源的形式化描述基础上,设计了一种信息栅格的传输体系,为一体化信息系统提供透明的传输服务。针对多重网络传输服务与网络性能的多样性,提出了一种基于作战任务的层次覆盖网络模型,以及实现网络负载均衡的QoS路由算法。     

Models to predict the deformation modulus and the coefficient of subgrade reaction for earth filling structures

Determination of deformation modulus and coefficient of subgrade reaction of soils have major importance, whether the projects are in design, and construction or compaction assessment stage of earth filling structures. Plate load test is one of the frequently used method to directly determine the parameters but the method is both costly and time consuming. For this reason, this paper is concerned with the applications of artificial neural networks (ANN) and simple-multiple regression analysis to predict deformation modulus and coefficient of subgrade reaction of compacted soils from compaction parameters (such as maximum dry density (MDD) and optimum moisture content (OMC), field dry density (FDD), and field moisture content (FMC)). Regression analysis and artificial neural network estimation indicated that there are acceptable correlations between deformation modulus and coefficient of subgrade reaction and these parameters. Artificial neural networks model exhibits higher performance than traditional statistical model for predicting deformation modulus and coefficient of subgrade reaction.     

一种面向连续数据保护的分布式存储模型研究

一个典型的连续数据保护(CDP,Continuous Data Protection)系统必须具有一个高效的存储系统来支撑.本文提出了一种分布式的存储模型,在此基础之上设计了一个面向CDP应用的分布式存储系统.同传统CDP系统相比,本文提出了分布式存储应用于CDP应用,将文件级和块级的数据存储都归纳到一个存储系统中;通过引入了元数据和数据分离的思想,并且把数据分级存储.根据原型系统的理论论证以及测试,结果表明,论文所提存储模型很好的解决了CDP服务器低效率,高负荷的问题,并且具有低成本的优势.     

Evaluating learners’ motivational and cognitive processing in an online game-based learning environment

This paper describes the process and results of an evaluation on an online game-based learning environment (GBLE) by focusing on learners’ motivational processing and cognitive processing. The goal is to explore how online GBLE might initiate and support learners’ goal-setting activities and impact learners’ cognitive loads. The study surveyed 144 undergraduate students after their autonomous participation in the online game available at the Nobel Prize Foundation website teaching the Heckscher-Ohlin Theory on international trade. Grounded in the integrative theory of motivation, volition, and performance (MVP), the evaluation indicated that participants felt significantly confident in learning the subject. The perceived satisfaction, however, was lower than the rest of motivational components possibly due to heavy cognitive processing. The finding of cognitive load reported that learners perceived a significantly higher level of intrinsic load than the germane load due to the novelty of the subject matter. Data analysis further indicated a significant canonical correlation between learners’ motivational and cognitive processing. This particular finding could inform future research to investigate specific motivational processing components’ effects on learners’ cognitive load levels in online GBLEs.     

Examining different types of collaborative learning in a complex computer-based environment: A cognitive load approach

This study compared the effects of two collaborative learning strategies (Open-ended and Task-based) with an individualized learning strategy on individual learning in a computer-based environment. The experiment sought ecological validity by conducting it under real teaching and homework conditions. Ninety-four students from grade 9 participated in a webpage design task. Cognitive load theory was used to predict that the collaborative approaches would outperform the individualized approach due to reduced cognitive load. This hypothesis was confirmed by performance scores and cognitive load only in the case of the Open-ended collaborative learning condition. Evidence was also found that the Open-ended collaborative learning condition outperformed the Task-based collaborative one. It was concluded that in collaborative learning a more Open-ended task design together with moderate independent sub-task requirements leads to more effective learning.     

The double-edged effects of explanation prompts

Explanation prompts usually foster conceptual understanding. However, it has been claimed within cognitive load theory that prompts can take cognitive load to the upper limit when learning complex contents. Under such circumstances, prompts focusing the learners’ attention on specific aspects (e.g., conceptual aspects such as elaborations on domain principles) might have some costs: Other important aspects (e.g., procedural aspects such as how to calculate) cannot be processed deeply. Thus, we expected that conceptually-oriented explanation prompts would foster the detailedness of explanations, the number of elaborations on domain principles, and conceptual knowledge. In addition, we tested the influence of such prompts on the number of calculations performed during learning and procedural knowledge. We conducted an experiment in which we employed conceptually-oriented explanation prompts in a complex e-learning module on tax law. Tax law university students (N = 40) worked on this e-learning module under two conditions: (a) conceptually-oriented explanation prompts, (b) no prompts. The prompts led to double-edged effects: positive effects on the detailedness of explanations and on the number of elaborations on domain principles, as well as on conceptual knowledge and simultaneously negative effects on the number of calculations performed during learning as well as on procedural knowledge.