Learning statistics with interactive pictures using R Shiny: Generally preferred,but not generally advantageous

Constructing interactive web apps has become more accessible for instructors, for example, by using the R package Shiny. Here we explored learners' preferences and the efficiency of interactive simulations versus static pictures in acquiring statistics knowledge of Cohen's d and standard normal distribution. Results revealed that students' spontaneous interaction with pictures was infrequent (pilot study, N = 26). While prompts (Exp. 1, N = 152) effectively ensured the manipulation of simulations, student exposure to interactive simulations led to longer learning times though similar test performance compared with student exposure to static pictures. Multiple interactive representations led to lower test performance than single interactive and static representations (Exp. 2, N = 117). Though no advantage was gained regarding learning outcomes, participants preferred the interactive variant (Exp. 3, N = 119). Taken together, this study demonstrates that the superiority of interactive pictures cannot be assumed to hold in general. Further work should evaluate how mental model construction can be effectively scaffolded by interactive simulations.     

协同创新视角下高职院校图书馆构建社会化信息服务平台的探索与研究

协同创新是高职院校图书馆开展社会化服务的新动力.高职院校图书馆的社会化服务对象主要面向行业产业和地方区域,具有自己独特的优势和特色.高职院校图书馆构建基于协同创新的社会化信息服务平台要实现可持续发展,需要相应的保障机制.     

Multi-objective output feedback control for autonomous spacecraft rendezvous

In this paper, the problem of robust output feedback control for a class of spacecraft rendezvous systems is investigated, which contains parameter uncertainty, external disturbance, poles assignment, _H∞-norm$H_{\infty }\mathrm{-}\mathrm{norm}$, variance and input constraints. The aim of this problem is to design a dynamic output feedback controller such that the closed-loop poles are placed within a specified disc, the _H∞$H_{\infty }$ norm of the transfer function from disturbance to output is ensured to be less than a prespecified disturbance attenuation level, the steady-state variance for each state of spacecraft rendezvous system is guaranteed to be less than the prespecified individual upper bound, and the actual control input is confined into a certain range simultaneously. Based on the Lyapunov theory, the existence conditions of such controller are derived in terms of linear matrix inequalities (LMIs). An illustrative example is given to demonstrate the effectiveness of the proposed control design method.     

Further result on H∞ filter design for continuous-time Markovian jump systems with time-varying delay

This paper investigates the problem of _H∞$H_{\infty }$ filtering for Markovian jump linear systems with time-varying delay. The aim of this problem is to design an _H∞$H_{\infty }$ filter that ensures stochastic stability of the filtering error system and a prescribed L₂-induced gain from the noise signals to the estimation error, for all admissible uncertainties. For solving the problem, we transform the system under consideration into an interconnection system. Based on the system transformation and the stochastic scaled small gain theorem, stochastic stability of the original system is examined via the stochastic stability version of the bounded realness of the transformed forward system. The merit of the proposed approach lies in its reduced conservatism, which is made possible by a precise approximation of the time-varying delay and the stochastic scaled small gain theorem. The proposed _H∞$H_{\infty }$ filtering condition is demonstrated to be less conservative than most existing results. Moreover, the _H∞$H_{\infty }$ filter design condition is further presented via convex optimizations, whose effectiveness are also illustrated via numerical examples.     

An evaluation framework for cross-lingual link discovery

Cross-Lingual Link Discovery (CLLD) is a new problem in Information Retrieval. The aim is to automatically identify meaningful and relevant hypertext links between documents in different languages. This is particularly helpful in knowledge discovery if a multi-lingual knowledge base is sparse in one language or another, or the topical coverage in each language is different; such is the case with Wikipedia. Techniques for identifying new and topically relevant cross-lingual links are a current topic of interest at NTCIR where the CrossLink task has been running since the 2011 NTCIR-9. This paper presents the evaluation framework for benchmarking algorithms for cross-lingual link discovery evaluated in the context of NTCIR-9.     

动态环境下组织冗余对企业探索的影响研究

以往学者往往关注组织冗余对企业绩效的最终影响,而对更为微观的企业探索的影响关注的较少。本文基于资源基础理论和惰性理论,以中国187个高科技制造企业为研究对象,检验了组织冗余与企业探索之间的关系。研究发现:(1)组织冗余对企业探索有显著的积极影响;(2)环境动态性对上述关系具有显著的负向调节作用。这一结果表明单一的理论视角难以全面解释组织冗余对企业探索的影响,将资源基础理论和惰性理论结合起来能增进我们对这一现象的理解。     

高技术产业与区域经济共同演化水平研究

高技术产业与区域经济之间共同演化水平的高低直接关系到经济的可持续发展。本文基于共同演化理论,构建我国高技术产业系统与所在区域经济系统的演化模型;并运用协同学的分析方法,选取相应的序变量,形成两系统共同演化水平评价指标体系,采用全国30个省市(西藏除外)的数据,对我国各地区两系统的演化水平进行实证分析。研究发现:不同地区两系统的共同演化水平呈现显著的四梯度分布,演化过程表现为持续提升和往复波动并存,总体演化水平较低且东西部差距明显。     

制冷剂循环性能的标准化检测方法及其应用研究

为了满足制冷剂产品的替代工作要求,解决产品替代研究和质量监管中缺少循环性能的标准化检测方法问题,填补制冷剂循环性能标准化检测领域的空白,本文基于电量热器原理提出了一种制冷剂循环性能的标准化检测方法,通过对循环系统中蒸发温度、冷凝温度、过冷度以及过热度的调节实现制冷剂试验工况的控制。搭建标准化检测装置,建立系统漏热标定和补偿计算方法,实现对制冷剂制冷量、单位质量制冷量、单位容积制冷量等循环性能参数的检测计算。并针对汽车空调中常用的制冷剂产品R134a进行了变工况试验应用研究,结果表明,该检测系统具有系统简单,调节方便,运行稳定,可靠性高等优点,易于标准化推广。     

基于RSSI差值加权的质心定位算法

由于RSSI值随机变化较大,使得直接利用RSSI值作为依据来计算信标节点的权值的加权质心定位算法在定位过程中存在较大误差。针对这一问题,提出基于RSSI差值加权的定位算法,利用网络中信标节点之间的距离和相应的RSSI值作为参考,并将测得的RSSI值与信标节点之间的RSSI值作为差值,根据差值的大小判断所测距离与信标节点之间距离的接近程度,以此来减小实际环境对加权质心定位算法的影响。仿真结果表明,与基于RSSI校验的定位算法相比,该方法进一步减小了定位误差。