基于网络的科学问题求解环境研究

科学问题求解环境以一套高效的科学计算工具集为基础,为求解科学问题提供了一个方便易用的平台。把传统的科学问题求解环境同网络的共享与协同特征相结合,为满足科学问题求解过程中普遍存在的知识复用与大规模计算的需求提供了新的机遇。该文介绍了科学问题求解环境的发展历史及存在的问题,在此基础上提出了一种解决方案——基于网络的科学问题求解环境(Grid-PSE)。     

科学数据网格中面向天文应用的问题求解环境设计与实现*

通过对虚拟天文台中科学课题的需求分析,提出一种基于数据网格针对天文应用的问题求解环境的框架;以"2MASS巡天星表搜寻OB星协候选体研究银河系的旋臂结构"科学课题为例,在科学数据网格上设计和实现了面向天文应用的问题求解环境,并对实现中的关键技术进行研究.     

运输问题的神经网络解法

给出了利用Hopfield连续模型求解运输问题的数值算法,是对运筹学知识的补充和完善,是借助人工神经网络计算机原理解决组合优化问题的一个成功范例。     

可扩展的桌面问题求解环境计算加速中间件

为利用多种高性能计算资源的计算能力,设计一种可扩展的桌面问题求解环境计算加速中间件,采用应用层、中间层和计算层 3层结构,以降低系统设计的复杂度,支持多种并行后端、分布式扩展以及并行后端的即插即用。用该加速中间件进行Matlab中的LU分解实验,结果证明了其有效性。     

可扩展的桌面问题求解环境计算加速中间件

为利用多种高性能计算资源的计算能力,设计一种可扩展的桌面问题求解环境计算加速中间件,采用应用层、中间层和计算层3层结构,以降低系统设计的复杂度,支持多种并行后端、分布式扩展以及并行后端的即插即用。用该加速中间件进行Matlab中的LU分解实验,结果证明了其有效性。     

半在线调度中约束求解算法研究

很多实际调度问题是半在线的. 尝试运用人工智能方法来求解半在线调度问题, 首先简要介绍了半在线调度问题并对其约束模型进行了分类, 通过引入单调性约束扩展的相关概念, 从约束建模角度形式化描述 了一类动态约束扩展, 并在此基础上设计了一个完备动态约束求解算法, 最后给出该算法在半在线离散资源约束调度求解的应用算例. 测试结果表明, 该算法是可行有效的.     

Problem solving through digital game design: A quantitative content analysis

Project Tech engages secondary students (ages 14 to 17) in the process of digital game design in a variety of in-school, after-school, and secure settings. The goal of Project Tech is to leverage students’ interests in games and design to foster their problem-solving in a supportive environment where they learn to create games about a social issue they have experienced personally. The present study compares the in-school special needs version of Project Tech (n = 11) to examine problem solving. Students enrolled in Project Tech were guided in the process of designing digital games aimed at teaching younger students (ages 12–15) about social issues facing teenagers. A quantitative content analysis was conducted on 35 iterations of a directed design game and 35 iterations of a free design game created by special needs young people and director notes. The purpose of the study was to draw from the game iterations a list of empirically grounded problem solving attributes that are associated with digital game design in a special needs classroom. The findings of the study resulted in the understanding of problem solving with special needs young people in four areas: representative characteristics, planning characteristics, executing characteristics and evaluation characteristics.     

Easily too difficult: Estimating item difficulty in computer simulated microworlds

Dealing with complexity and dynamics is increasingly becoming part of people's everyday lives. The necessity of dealing with complex systems has instigated the use of computer simulations, so-called microworlds (MWs), to assess and study human behavior in complex situations. Although these MWs enjoy great popularity with both practitioners and researchers, their psychometric qualities have been questioned, and studies that have investigated these qualities have been sparse. In particular, only a few studies have investigated the factors that contribute to item difficulty in MWs. To fill this gap, we analyzed data from 3128 Finnish students with a linear logistic test model. Our results suggest that item difficulty in MWs can be almost perfectly predicted by six basic item characteristics, namely, (a) the use and number of eigendynamics, the numbers of (b) input and (c) output variables, the numbers of (d) input and (e) output variables not related to any other variables, and (f) the total number of relations between all variables. In addition, we provide evidence for the necessity of differentiating between the difficulty of controlling an MW (knowledge application) and understanding its underlying structure (knowledge acquisition). Finally, we discuss further theoretical and practical implications of an increased understanding of MWs for their use as assessment instruments.     

A problem-solving based computer-assisted tutorial for the earth sciences

Abstract This study investigated the effects of a Problem-Solving based Computer-Assisted Tutorial (PSCAT) on earth science achievement and attitudes toward earth science of tenth graders (16-year olds) in a senior high school in Taiwan. A total of 137 students who were enrolled in four earth science classes participated in this pre-test/post-test control-group experiment. The experimental groups received the PSCAT; whereas the comparison groups received a Lecture-Internet-Discussion (LID) teaching approach. A multivariate analysis of covariance on the post-test scores of the Earth Science Achievement Test and Attitudes Toward Earth Science Inventory, with students' pre-test scores as the covariates, suggested that PSCAT produced (almost) significantly greater gains on students' earth science achievement than did the LID approach and that no statistically significant increase or decrease in student attitudes toward earth science was found for either group.     

货郎担问题的几何分块算法及ChinaTSP问题的最终解决

本文提出了货郎问题后一种新的求解方法，即几何分块算法，用该方法找到了ＣｈｉａｎＴＳＰ问题的最短路径，并分析了求解中的一些策略问题。     

Unpopping: Solving the Image-Space Blend Problem for Smooth Discrete LOD Transitions

This paper presents a new, simple and practical algorithm to avoid artifacts when switching between discrete levels of detail (LOD) by smoothly blending LOD representations in image space. We analyse the alternatives of conventional alpha‐blending and so‐called late‐switching (the switching of LODs ‘far enough’ from the eye‐point), widely thought to solve the LOD switching discontinuity problem, and conclude that they either do not work in practice, or defeat the concept of LODs. In contrast we show that our algorithm produces visually pleasing blends for static and animated discrete LODs, for discrete LODs with different types of LOD representations (e.g. billboards and meshes) and even to some extent totally different objects with similar spatial extent, with a very small runtime overhead.     

一种解偏微分方程逆问题的并行算法

论述一种偏微分方程逆问题的数值解法和阵列机与 PVM平台上实现的并行算法。     

分布式问题求解方案的模糊综合评价模型及其算法实现

为解决现阶段大型复杂工程方案评价缺少实用理论分析工具的问题,文章应用“主因素突出型”和“因素加权型”两种多阶段模糊评判模型,实现了一种适合大型工程分布式协同设计的方案模糊综合评价算法。文中首先分析了大型工程分布式问题求解过程,提出了一种面向工程的分布式问题求解逻辑结构;其次详细分析了多阶段方案模糊评价模型以及模糊综合评价算法的流程框图及其实现过程。     

Simulated Annealing and the Generation of the Objective Function: A Model of Learning During Problem Solving

A computational model of problem solving based on significant aspects of human problem solving is introduced. It is observed that during problem solving humans often start searching more or less randomly, becoming more deterministic over time as they learn more about the problem. This two‐phase aspect of problem‐solving behavior and its relation to learning is one of the important features this model accounts for. The model uses an accelerated simulated annealing technique as a search mechanism within a real‐time dynamic programming‐like framework upon a connected graph of neighboring problem states. The objective value of each node is adjusted as the model moves between nodes, learning more accurate values for the nodes and also compensating for misleading heuristic information as it does so. In this manner the model is shown to learn to more effectively solve isomorphs of the Balls and Boxes and Tower of Hanoi problems. The major issues investigated with the model are (a) whether such a simulated annealing‐based model exhibits the kind of random‐to‐directed transition in behavior exhibited by people, and (b) whether the progressive discovery of the objective function, even when given very little or poor initial information, is a plausible method for representing the learning that occurs during problem solving and the knowledge that results from that learning.     

EPPOD: A Problem Solving Environment for Parallel Electronic Prototyping of Physical Object Design

One of the grand challenges for computer applications is the creation of a system that will provide accurate computer simulations of physical objects coupled with powerful design optimization tools to allow optimum prototyping and the final design of a broad range of physical objects. We refer to such a software environment aselectronic prototyping for physical object design (EPPOD). The research challenges in building such systems are in softwareintegration, in utilizingmassive parallelismto satisfy their large computational requirements, in incorporatingknowledgeinto the entire electronic prototyping process, in creatingintelligentuser interfaces for such systems, and in advancing thealgorithmic infrastructureneeded to support the desired functionality. In this paper we address issues related to the parallel processing of the computationally intensive components of the EPPOD problem solving environment on message passing parallel machines and present its software architecture. The parallel methodology adopted to map the underlying computations to parallel machines is based on the optimal decomposition of continuous and discrete geometric data associated with the physical object. One of the main goals of this methodology is thereuseof existing software parts while implementing various components of the EPPOD system on parallel computational environments. Finally, some performance data of the parallel algorithmic infrastructured developed are listed and discussed.     

PEARD: A Prototype Environment for Active Rule Debugging

This research has investigated dynamic, execution-based rule analysis through the development of a Prototype Environment for Active Rule Debugging, called PEARD. PEARD simulates the execution of active database rules, supporting the Event-Condition-Action rule paradigm. Rule definition is flexible, where changes to rules can be applied immediately during a debugging session without recompiling the system. A breakpoint debugging tool allows breakpoints to be set so that the state of variables may be inspected and changed anytime a breakpoint is reached during rule execution. A rule visualization tool displays the rule triggering process in graph form, supporting different visualization granularities to help the user to understand rule execution. Color coding is also used as part of the visualization tool to help the user see where the different parts of an ECA rule are executed due to deferred coupling modes. Users can examine different parts of the rule graph display to inspect the state of a transaction at different rule execution points. Other debugging features include a means for detecting potential cycles in rule execution and a utility to examine different rule execution paths from the same point in the rule triggering process. Our experience with PEARD has helped to identify some of the useful functional components of an active rule debugging tool and to identify research directions for future active rule development environments.This research was partially supported by NSF Grant No. IRI-9410993.     

一种电影推荐模型：解决冷启动问题

推荐系统数据库的评分数据稀少,对电影推荐的质量有所限制。为解决这个问题,提出一种同时将用户和电影元数据纳入改进的隐语义模型的模型。构造用户元数据-分类矩阵与电影元数据-分类矩阵,将分类域与隐因子空间进行映射,以此获取新用户与新电影的隐因子,进行推荐。实验结果表明,这种模型在提高预测准确率的同时,有效地解决了冷启动问题。     

A Parallel Genetic Algorithm for Solving the Container Loading Problem

This paper presents a parallel genetic algorithm (PGA) for the container loading problem with a single container to be loaded. The emphasis is on the case of a strongly heterogeneous load. The PGA follows a migration model. Several separate sub-populations are subjected to an evolutionary process independently of each other. At the same time the best individuals are exchanged between the sub-populations. The evolution of the different sub-populations is carried out on a corresponding number of LAN workstations. The quality of the PGA is demonstrated by an extensive comparative test including well-known reference problems and loading procedures from other authors.     

EH—GRBAC：遍在计算环境中基于知识的访问控制原型

In pervasive computing environment, users can access to various information, resources and services at anytime and anywhere, so access control has become an exigent security problem. In the traditional access control modes, the decisions o[ access control are entirely dependent on the results of authentication. The access control can-not provide the security-relevant fault-tolerant function. But in pervasive computing environment, because of the var-ious reasons, security system can't assure the results of the authentication are absolutely correct. So we propose touse the knowledge-based access control, which can discovery some rules and knowledge from the previous process ofaccess control and combine these rules with traditional access controls to perfect the security system. The essence ofknowledge-based access control is to add some intelligent authentication function into the process of access control. In the paper, we expatiate the idea and principle of knowledge-based access control, as well as the advances of this method. Furthermore, we implement a prototype, called EH-GRBAC, which can discovery historical knowledge from the history of users' using resources to reinforce GRBAC. In the paper, we also explain the architecture and the details of EH_GRBAC.