功率键合图在液压系统动态特性数字仿真研究中的应用

本文以直动式溢流阀调压系统动态特性的数字仿真研究为例，详细地介绍了功率健合图的符号规则；以及按照其规则由物理模型建立健图模型和由键图模型建立数字仿真模型──状态方程的步骤和方法，对于机电系统的数字仿真研究具有一定的借鉴意义。     

Distance education and international social work education

As a result of the development of new communication technology, distance education has become a rapidly growing area over the last few decades. Market and commercial pressures are major factors in its developing impact. Distance education has also been applied to social work education. Because it is a small field it may be both positively and negatively affected. Social work education requires face-to-face communication training. Educators need to respond to the limitations of distance education technologies and processes to provide for cultural and linguistic diversity, through openness to joint work across different cultures, anti-standardisation and -discrimination, reflexivity, user control and resources, and cultural and language translation.     

干线战术通信网的抗毁模型研究

介绍了抗毁通信网分析与设计的原理和方法、针对干线战术通信网中节点移动会导致网络拓扑结构发生变化的特点,提出了动态网络拓扑设计模型和衡量干线战术通信网的抗毁性能的数学模型—随机图模型和齐次随机图模型、计算机模拟结果验证了随机图模型和齐次随机图模型的正确性.     

地理距离、方言文化与劳动力空间流动

本文基于百度迁徙大数据研究中国劳动力的空间流动，系统考察地理和文化对劳动力流动的影响。通过构造流动机会比率，基于引力模型和普通最小二乘法的研究表明地理距离和方言距离阻碍劳动力流动。在空间距离上，劳动力偏好邻近城市，地理距离每增加1%，劳动力的流动机会比率降低约0.6%。在空间位置上，劳动力倾向于在方言文化相近地域范围流动，方言距离每增加1%，劳动力的流动机会比率下降2%左右。通过构造两地年均降水量差距和小麦种植适宜度差距作为方言距离的工具变量，以两阶段最小二乘法估计缓解内生性问题，估计显示结论稳健。考虑普通话因素后方言距离的抑制影响依然稳健，但目的地的高普通话普及率显著发挥促进劳动力流动的引力作用。最后，本文得出持续推广普通话、加强交通建设和深化中等教育的政策建议。     

A case-based distance method for screening in multiple-criteria decision aid

Screening is a process of multiple-criteria decision aid (MCDA) in which a large set of alternatives is reduced to a smaller set that most likely contains the best choice. We propose screening using a distance model calibrated on the basis of the decision-maker's own judgement. Viewing MCDA as preference aggregation based on consequence data, we define consequence and preference expressions (values and weights) and describe how they are aggregated. Then we define screening and explain some of its properties. Using an appropriate definition of distance, our case-based distance method screens a set of alternatives using criterion weights and a distance threshold obtained by quadratic optimization using the decision-maker's selection of alternatives from a test set. This case-based method can elicit the decision maker's preferences more expeditiously and accurately than direct inquiry. An application in water supply planning is used to demonstrate the procedure.     

依存距离最小化是人类语言的普遍规律吗？

麻省理工学院（ MIT ）大脑与认知科学系的弗特勒尔等人对 37 种自然语言的进行了基于语料库的大数据分析,为人类语言中的依存距离最小化倾向提供了最新的实证依据,在科学研究领域引起广泛关注。 MIT 这项研究可能是迄今为止含有语言最多的依存距离研究,在普遍性的验证上较先前研究更为全面,在方法上也有自身的一些特点。但其结论与看法有多处值得商榷。早在八年前,浙江大学刘海涛团队对依存距离最小化倾向进行了较为深入的研究,推动了人们了解人类语言如何在普遍认知机制制约下形成与演化,也帮助人们更深入地认识人类的认知机制。这些研究充分体现了语言研究是一个具有交叉学科特点的研究领域,是多语言、大数据技术、语言的普遍规律、认知科学充分融合的学科。这四大因素结合起来的研究将会展现当代科学研究的光芒,并将对当代语言科学的发展起到重要的推动作用。     

Combinatorial Equivalence of Fractional Factorial Designs

Two symmetrical fractional factorial designs are said to be combinatorially equivalent if one design can be obtained from another by reordering the runs, relabeling the factors and relabeling the levels of one or more factors. This article presents concepts of ordered distance frequency matrix, distance frequency vector, and reduced distance frequency vector for a design. Necessary conditions for two designs to be combinatorial equivalent based on these concepts are presented. A new algorithm based on the results obtained is proposed to check combinatorial non-equivalence of two factorial designs and several illustrating examples are provided.     

基于CiteSpace的品牌营销国内研究的可视化分析

新媒体时代背景下,品牌营销研究迎来新的机遇与平台,为系统梳理国内品牌营销领域研究的发展阶段、前沿热点及营销方式,文章以中国知网数据库收录的品牌营销CSSCI期刊论文为样本,借助CiteSpace软件对文献作者、文献机构、关键词等方面进行可视化分析,并绘制知识图谱。研究发现,国内品牌营销经历了缓慢发展、繁荣发展、稳定发展三个阶段,研究成果更加丰富;当前,新媒体环境下社交媒体营销、大数据时代品牌传播及价值共创是研究热点;营销模式升级下品牌营销与新媒体融合的研究、品牌价值共创对品牌形象及品牌资产的研究、品牌营销研究方法创新性的研究、全球化背景下品牌国际营销的研究等是未来研究重点。     

关于圈C4的St(r+1)-冠的优美性

给出了圈C4的St(r+1)-冠的定义,讨论了圈C4的St(r+1)-冠的优美性,用构造性的方法,给出了圈C4的St(r+1)-冠的优美标号.同时,证明了圈C4的St(r+1)-冠是交错图.     

Impact of the tariff concessions of the RCEP agreement on the structure and evolution mechanism of manufacturing trade networks

In the world’s largest free trade area, the Regional Comprehensive Economic Partnership (RCEP) agreement will gradually eliminate tariffs on over 90% of member countries’ goods over the next 36 years. We construct a tariff policy effects evaluation framework based on the complex network theory. In this framework, the standard Global Trade Analysis Project (GTAP) model is recursively extended to generate forecasted data of bilateral trade. Based on this, we model the RCEP manufacturing trade networks and analyze the response of its core–periphery structure to the tariff concessions. Then, we evaluate policy effects on the evolution of trade patterns based on motif analysis. Finally, we construct separable temporal exponential family random graph models (STERGM) to explore the influence path and degree of the new tariff agreement on the evolutionary mechanisms of trade networks.