Understanding how student-constructed stop-motion animations promote mechanistic reasoning: A theoretical framework and empirical evidence

Previous studies have documented the promising results from student-constructed representations, including stop-motion animation (SMA), in supporting mechanistic reasoning (MR), which is considered an essential thinking skill in science education. Our current study presents theoretically and empirically how student-constructed SMA contributes to promoting MR. As a theoretical perspective, we propose a framework hypothesizing the link between elements of MR and the construction nature of SMA, that is, chunking and sequencing. We then examined the extent to which this framework was consistent with a multiple-case study in the domain of static electricity involving five secondary school students constructing and using their own SMA creation for reasoning. In addition, students' reasoning in pre- and postconstruction of an SMA was examined. Our empirical findings confirmed our framework by showing that all students identified the basic elements of MR, that is, entities and activities of entities, when engaging in chunking and sequencing. Chunking played a role in facilitating students to identify entities responsible for electrostatic phenomena, and sequencing seemed to elicit students to specify activities of these entities. The analysis of students' reasoning in pre- and postconstruction of SMA found that student-generated SMA has a potential effect on students' retention of the use of MR. Implications for instruction with SMA construction to support MR are discussed.     

电信机房综合管控系统设计

本文针对当前机房管理系统存在的不足,设计开发了一套电信机房综合管控系统软件,并构建了统一的网维机房综合监管平台。该系统可实现机房合同以及缴费数据等信息的自动化管理;提供能耗分析手段,为机房能耗改造提供依据;制定巡检模板和巡检流程,为代维人员制订明确的巡检任务要求,为考核代维人员提供明确的依据。     

Observer design for constrained nonlinear systems with application to secure communication

In this paper, a constrained regularized least square (RLS) state estimator is developed for deterministic discrete-time nonlinear dynamical systems subject to a set of equality and/or inequality constraints. The stability of the estimation error is rigorously analyzed. The proposed estimator is then used to handle the important problem of secure communication. At the transmitting end, the output of the constrained unified chaotic system is used as a chaotic mask to achieve a satisfactory and typical secure communication scheme. The encrypted data signal is injected into the transmitter and simultaneously transmitted to the receiver through a public channel. At the receiving end, the constrained RLS estimator is used to reconstruct the states of the constrained unified chaotic system. Simulation results are presented to show the impact of the imposed constraints on the waveform and the pattern of the generated chaotic signal as well as the ability of the proposed estimator to synchronize the actual and estimated states of the constrained unified chaotic system. Moreover, the proposed estimator is applied to recover discrete signals such as digital images where computer simulation results are provided to show the effectiveness of the proposed estimation scheme.     

Stabilization of positive constrained T–S fuzzy systems: Application to a Buck converter

This paper deals with the problem of constrained stability and tracking of Takagi–Sugeno (T–S) fuzzy positive systems. Linear programming (LP) is used to insert the constraints in the design phase while imposing positivity in closed-loop. The theoretical results are applied to the buck DC–DC converter which is widely used in the photovoltaic generators. Based on the simulation results success of the method is shown for this application.     

“P53 Codon 72 Single Base Substitution in Viral Hepatitis C and Hepatocarcinoma Incidences”

Viral infection with hepatitis C virus (HCV) has a high propensity in becoming chronic and it is the major cause of hepatocellular carcinoma (HCC) worldwide. This review was basically established to illustrate the putative role of the P53 gene Arg72Pro polymorphism on various cancer models and viral infections, focusing on HCV and HCC incidences. Authors studied the 72 G/C single base substitution of P53 gene at codon 72 using various polymorphic techniques. Intriguingly, authors investigated that the P53 codon 72 plays a crucial role as risk factor in several cancer models. Others found that there is no association between codon 72 genotypes and HCV disease severity or liver cancer. Moreover, the lack of a significant relationship between this polymorphism and risk of HCC shows that it does not predispose towards hepatocarcinogenesis and the frequent loss of the proline allele in HCV-associated carcinogenesis of the liver plays some critical role in hepatocarcinogenesis. Amazingly, there is a significant correlation between male homozygotes for P53 72Pro with HCV type 1b infection. However, there was no significant difference between the P53 polymorphism and HCV genotypes 2a and 2b. It was concluded that the P53 gene polymorphism at codon 72 has been investigated as potential risk factor in several cancer models and HCV infections.     

家族性因素对家族企业绩效影响的实证研究

家族企业在世界经济中占有重要的地位,研究者相信家族企业具有不同于非家族企业的独特性,于是将其区分出来进行单独研究。但目前的研究多只是简单地探讨家族企业独有的企业特征与非家族企业相比较所具有的优势或劣势,较少研究家族性因素对企业绩效的影响。本文通过文献研究及访谈调研,提出了家族性因素的四个维度,在此基础上构建了家族性因素与企业绩效的关系的研究框架,提出各因素与企业绩效的关系假设。最后,通过问卷调查获取家族性因素及企业绩效的数据,用SPSS13.0软件系统对各个因素与企业绩效之间进行相关性分析,偏相关分析,回归分析,以检验假设。研究表明"家族性因素"中信任度、家族成员间的交流、职业经理模式、愿景共享与企业成功和家族成功均有显著的正相关关系,而人情取向、柔性治理模式、多元化经营与企业成功和家族成功显著负相关关系。     

基于知识图谱的国际搜索引擎研究历程与热点演进

对国际上搜索引擎领域的研究文献进行比较细致、深入的考察,采用可视化方法进行定量分析并制作有关知识图谱,明晰国际搜索引擎研究的总体趋势和发展脉络。通过对高被引文献的深入解读和定性分析,以及近几年相关文献的共词分析,揭示国际上搜索引擎研究的起源和发展,以及从进入快速发展期至今四个阶段的研究热点演进历程。最后,总结和展望国际搜索引擎研究的热点方向。     

我国高校许可专利与专利权转让专利的对比分析

通过对许可专利与转让专利的总体情况、专利的地域特征、专利技术年龄以及专利技术领域等进行对比分析,结果显示:(1)我国高校许可专利数量远大于转让专利数量,主要是发明专利,集中分布在作业运输类以及化学冶金部类;(2)许可与转让专利输出和输入地区主要分布在经济较发达和高校资源较丰富的地区;(3)转让专利的技术年龄大于许可专利的技术年龄;(4)许可专利比转让专利的技术领域分布更加广泛,不同技术领域的专利适合不同的技术转移模式。     

压力与学习的互惠:对积极塑造者假说的纵贯实证检验

引入积极塑造者假说阐释工作压力与员工学习间的互惠关系,构建二者的良性循环,并据此提出两项中介假设;以研究院所、管理咨询机构的知识型员工为样本,采用两期107份纵贯样本进行回归分析;结果显示,员工学习中介工作压力与工作资源之间的正向关系,工作资源中介员工学习与工作压力之间的负向关系,压力与学习构成良性循环;研究表明,面对压力,积极塑造者将展开适应学习,习得知识后,积极塑造者将改变工作、获取资源以缓解压力,工作压力与员工学习良性互惠、员工福祉和技能螺旋上升。