Demystifying computational thinking

This paper examines the growing field of computational thinking (CT) in education. A review of the relevant literature shows a diversity in definitions, interventions, assessments, and models. After synthesizing various approaches used to develop the construct in K-16 settings, we have created the following working definition of CT: The conceptual foundation required to solve problems effectively and efficiently (i.e., algorithmically, with or without the assistance of computers) with solutions that are reusable in different contexts. This definition highlights that CT is primarily a way of thinking and acting, which can be exhibited through the use particular skills, which then can become the basis for performance-based assessments of CT skills. Based on the literature, we categorized CT into six main facets: decomposition, abstraction, algorithm design, debugging, iteration, and generalization. This paper shows examples of CT definitions, interventions, assessments, and models across a variety of disciplines, with a call for more extensive research in this area.     

城市建设系统的动力学模型研究

本文以复杂系统论和系统动力学为指导,从宏观和微观两个角度综合考虑,给出了城市建设系统的动力学模型,以探寻城市建设过程中的基本规律,促进城市建设同社会经济的协调发展和城市建设模式的进一步合理化,为城市建设质量的提高提供支持。     

Off line simulation system of machining processes

The primary objective for modeling of machining processes is to develop a predictive capability of machining performance in order to facilitate effective planning of machining operations. This capability leads to faster implementation, higher performance, quality at a lower cost. This comes about due to improved selection of machining parameters, optimal fixture design and the avoidance of tool failure. The simulation system presented simultaneously considers the effect of cutter geometry, the cutter's initial position errors, workpiece geometry, machine tool dynamics, and workpiece/fixture system dynamics on the machining process.The integration of all of the above in one model provides an off-line tool to simulate and optimize the machining parameters and the fixture configuration cutting both lead and production time. The modular nature of the simulation system presented allows for the study of many different machining processes. The cutting forces in this system are modeled using a mechanistic approach. NURBS curves and surfaces are utilized for the geometric modeling and simulation of the machining process. While a finite element method is used to model and analyze the workpiece/fixture dynamics. Two case studies are presented to demonstrate the practical application of the presented simulation. The first case presents the optimization of the fixture configuration of a generic automotive component. While the second case presents the results of simulations performed on a novel mill/grind machining process. This process is a combination of face milling and grinding in one operation. Some simulated results are presented along with experimental validation.     

系统生物学研究进展

人类基因组计划把生物学由分子生物学时代推向系统生物学时代,生物学由分解转向整合,由叙述科学转变为定量预测科学。     

基于企业战略路径系统演化的动态能力体系

围绕企业战略路径的演化全周期,提出并剖析动态能力在各个阶段发挥作用的主要维度,提出相关假设;在此基础上,限定战略路径演化的系统边界,根据理论分析建立系统动力学模型并进行仿真,最后通过灵敏性测试证明并构建感知判断能力、学习吸收能力、试错匹配能力、学习应用能力和战略柔性能力为维度的动态能力体系。     

基于SD的技术标准化与技术创新交互模型构建

在分析技术标准化和技术创新运行机理的基础上,明晰两大系统之间的交互作用,运用系统动力学方法构建随过程发展演变的技术标准化与技术创新交互模型,以更好地挖掘两大系统之间的交互关系,为完善技术标准化体系和提升技术创新能力提供理论依据,为有效联结两大系统、构建协调的技术基础结构、共同促进经济增长提供一个新思路。     

产业集群演进的系统动力学分析

本文将企业在特定地区内的进入、退出和增长模型化，进而对该地区产业集群的演进进行了研究．结果表明：无论何种产业首先出现，一个产业集群的区位影响其他产业发展。     

进度视角下地铁项目施工安全风险的系统动力学分析

在分析地铁施工安全风险影响因素的基础上,从进度的视角构建了地铁项目施工安全风险的系统动力学模型,并收集数据进行模型仿真。通过调整影响进度压力的三个关键变量——期望劳动力、工作强度和加班时间的权重赋值来进行政策模拟。研究结果表明:增加劳动力是降低系统安全和进度风险水平最有效的方式;增加工作强度的方式不可作为首要策略;在不同的系统目标优先度下,管理者对这三个变量应给予差异化的管理排序。     

企业创新氛围、双元组织学习与创新绩效——环境动态性的调节效应

创新氛围作为企业创新活动的“软环境”,对双元组织学习以及创新绩效具有重要影响。以高新技术企业为对象,根据大样本问卷调查数据,运用结构方程模型,实证研究了企业创新氛围、双元组织学习与创新绩效之间的关系,并重点分析了双元组织学习的中介作用以及环境动态性的调节效应。结果表明：企业创新氛围对创新绩效具有显著正向影响,双元组织学习在企业创新氛围与创新绩效之间具有完全中介作用；环境动态性负向影响创新绩效,但对企业创新氛围与创新绩效关系的调节效应并不显著。研究结果不仅对企业创新氛围与双元组织学习的深入研究具有重要理论启示,同时对我国企业在经营管理实践中重视创新氛围和双元组织学习具有重要的现实指导意义。     

Study of adenosine deaminase activity in various arthritic conditions

Aim of present study was to compare the adenosine deaminase (ADA) activity in various types of arthritis conditions with synovial effusion. No. significant difference was observed in ADA activity in serum of control and study groups but results have shown a definite pattern of ADA activity in synovial fluid in various arthritic conditions. The highest value of ADA activity was observed in synovial fluid of patients with tubercular arthritis followed by rheumatoid, septic, osteo and post traumatic arthritis. Thus measurement of ADA activity in synovial fluid can be used as a parameter of differential diagnosis of arthritis specially tubercular in initial stages.