基于熵权-TOPSIS模型的大风浪条件下引航员登船水域选址     

周宁  范中洲  赵羿 《上海海事大学学报》2020,41(1):46-50

为保障大风浪条件下引航员登船安全、周边船和被引船的安全以及港口的安全高效运营,选取合理的引航员登船水域至关重要。综合考虑熵权法和TOPSIS法的优点,基于熵权-TOPSIS模型对大风浪条件下引航员登船水域进行优选研究。以大风浪条件下广州港引航员登船水域选址为例,运用该模型对3个备选方案进行评价,求得方案2的相对贴近度最大。该方案所述的引航员登船水域为大风浪条件下最优登船水域,且与实际选址一致。经实例验证,该模型较为可靠,实用性强。  相似文献   

安全情报概念的由来、演进趋势及涵义——来自安全科学学理角度的思辨     

王秉  吴超 《图书情报工作》2019,63(3):45-53

[目的/意义]安全问题是当前国家、政府、企业、社会、大众及学界广泛关注的一个重要现实问题，而安全情报是保障安全的必用之宝，故安全情报研究具有十分重要的理论与现实意义。[方法/过程]运用文献分析法和思辨法，从安全科学学理角度出发，论证基于安全科学视角解读与界定安全情报概念的必要性、重要性与紧迫性，探讨安全情报概念的由来与演进趋势，并分析安全情报的涵义。[结果/结论]从安全科学学理角度看，从安全信息到安全情报的安全管理新认识是提出安全情报概念的根本动力，安全情报概念的总体演进趋势是从分散到统一。同时，从系统安全学角度看，安全情报是指所有影响系统安全行为的安全信息。  相似文献   

Location extraction from tweets     

Thi Bich Ngoc Hoang  Josiane Mothe 《Information processing & management》2018,54(2):129-144

Five hundred million tweets are posted daily, making Twitter a major social media platform from which topical information on events can be extracted. These events are represented by three main dimensions: time, location and entity-related information. The focus of this paper is location, which is an essential dimension for geo-spatial applications, either when helping rescue operations during a disaster or when used for contextual recommendations. While the first type of application needs high recall, the second is more precision-oriented. This paper studies the recall/precision trade-off, combining different methods to extract locations. In the context of short posts, applying tools that have been developed for natural language is not sufficient given the nature of tweets which are generally too short to be linguistically correct. Also bearing in mind the high number of posts that need to be handled, we hypothesize that predicting whether a post contains a location or not could make the location extractors more focused and thus more effective. We introduce a model to predict whether a tweet contains a location or not and show that location prediction is a useful pre-processing step for location extraction. We define a number of new tweet features and we conduct an intensive evaluation. Our findings are that (1) combining existing location extraction tools is effective for precision-oriented or recall-oriented results, (2) enriching tweet representation is effective for predicting whether a tweet contains a location or not, (3) words appearing in a geography gazetteer and the occurrence of a preposition just before a proper noun are the two most important features for predicting the occurrence of a location in tweets, and (4) the accuracy of location extraction improves when it is possible to predict that there is a location in a tweet.  相似文献   

The determinants of the intention to continue voluntary football refereeing     

《Sport Management Review》2020,23(2):242-255

Competitive sports require a regulating body of referees to enforce the rules for the effective operation of the game. However, the number of referees is generally decreasing, leading to organisational problems at the amateur level. The purpose of this research is to identify the factors that determine the intention to continue voluntary refereeing in the context of football in Germany. Combining several concepts as predictors, including both the antecedents and the experience of volunteering, in this study, the authors extend the understanding about volunteers’ intentions to continue their activity and address the research gap regarding the analyses of specific volunteer groups such as referees. By means of an online questionnaire, the authors surveyed voluntary football referees in Germany (n = 4541). Regression analysis reveals the motive of self-orientation, respect shown by athletes, coaches, and spectators towards referees, compatibility of refereeing with one’s occupational and private life, perceived organisational support, and referees’ satisfaction to predict referees’ positive intention to continue with their activity. Simultaneously, experiences of offences during refereeing negatively influence this intention, and younger referees show higher intentions to continue their activity than do older referees. Because volunteer recruitment and retention are expensive, the findings of this study facilitate the improvement of effective retention strategies for the federations responsible for referees.  相似文献   

新媒体用户的内容消费特征与媒介使用模式——以百度百家号的调研分析结论为例(2)     

喻国明学术工作室  喻国明  刘淼  韩婷 《传媒观察》2020,(5):32-38

本文把视线聚焦在新媒体的媒体语境当中,以百度百家号为例,考察了新媒体用户在内容层面、认知层面和行为层面上的认知与使用模式。基于对百度百家号用户媒介认知与媒介使用情况的网络问卷调查数据,本研究从新媒体用户重点关注的文章类型、内容来源的关注度以及网络内容的信任度三个方面分析了新媒体用户的内容消费特征并提出了优化网络内容平台内容建设机制及信息扩散机制的策略与建议。在用户层面,需重点培养激活核心用户以提升内容生态的活跃度;在平台层面,需纳入优质内容资源,重视品牌建设。  相似文献   

体育产业高质量发展系统动力机制模型建构与现实考察     

薛昭铭  刘东升  马德浩 《沈阳体育学院学报》2020,(2):116-124

通过文献资料法和案例分析法,以系统论为视角对体育产业高质量发展进行动力机制模型建构,并以江苏体育产业发展经验作为现实考察。研究认为:体育产业高质量发展作为政策性议题,其实践取向应围绕产业的商业性效益逻辑和体育的人文性功能价值进行有机融合,进而推动体育产业在社会主要矛盾、资源配置方式、产业结构模式、经济增长状态4个维度中积极寻求转向。推进体育产业转向高质量发展是一个系统问题,系统运转的关键在于形成运动项目内涵丰富的内生机制、社会进步和经济发展环境的外发机制以及业态载体和空间载体充沛的内外联动机制。当前运动项目产业化内在张力不足、外部环境要素缺位、空间载体培育良莠不齐是现实挑战。提出注重深度内涵式发展、强化务实载体建设、营造适宜外部环境3个由意识理念引领到具体工作抓手的发展思路。  相似文献   

Towards a Framework for Evaluating the Research Performance of Chinese Double First-Class Universities     

XU Changqing 《Frontiers of Education in China》2020,15(3):369

The study focuses on the research performance of Double First-Class (DFC) universities in China. A theoretical framework based on economic theory and the Analytic Hierarchy Process (AHP) method for a novel evaluation model is proposed. The model is performed on a sample of 41 participant DFC universities in China. Using data collected from these universities, it was found that there is no consistency between performance ranking, input ranking, and output ranking, with the best ranked universities far from the most efficient. These findings provide empirical evidence of DFC universities’ research performance situation and suggest strategies that the government can use to propel their sustainable development.  相似文献   

基于短时交通流量预测对路网微观交通仿真的研究     

张虎 《苏州市职业大学学报》2021,(1)

针对早高峰短时交通流量预测数据少、波动大的特点,提出用灰色模型进行预测。将灰色GM(2,1)改进为灰色GM(2,1,λ,ρ)预测模型,以提高预测精度。针对粒子群算法(PSO)的早熟现象,将Logistic混沌搜索嵌入到PSO算法,应用混沌粒子群算法(CPSO)寻找灰色GM(2,1,λ,ρ)预测模型最优的参数λ和ρ。结合两者提出了基于CPSO–GM(2,1,λ,ρ)的早高峰短时交通流预测模型。利用VISSIM对研究路网进行微观交通仿真,通过VISSIM–Excel、VBA–Matlab平台实现了短时交通流量预测和路网微观交通仿真数据的交互,对集成交通控制系统的架构进行了方案设计。仿真结果表明,结合流量预测的路网优于固定信号配时下的路网仿真。  相似文献   

Diagnosing Teachers’ Understandings of Rational Numbers: Building a Multidimensional Test Within the Diagnostic Classification Framework     

Laine Bradshaw  Andrew Izsák  Jonathan Templin  Erik Jacobson 《Educational Measurement》2014,33(1):2-14

We report a multidimensional test that examines middle grades teachers’ understanding of fraction arithmetic, especially multiplication and division. The test is based on four attributes identified through an analysis of the extensive mathematics education research literature on teachers’ and students’ reasoning in this content area. We administered the test to a national sample of 990 in‐service middle grades teachers and analyzed the item responses using the log‐linear cognitive diagnosis model. We report the diagnostic quality of the test at the item level, mastery classifications for teachers, and attribute relationships. Our results demonstrate that, when a test is grounded in research on cognition and is designed to be multidimensional from the onset, it is possible to use diagnostic classification models to detect distinct patterns of attribute mastery.  相似文献   

An NCME Instructional Module on Polytomous Item Response Theory Models     

Randall David Penfield 《Educational Measurement》2014,33(1):36-48

A polytomous item is one for which the responses are scored according to three or more categories. Given the increasing use of polytomous items in assessment practices, item response theory (IRT) models specialized for polytomous items are becoming increasingly common. The purpose of this ITEMS module is to provide an accessible overview of polytomous IRT models. The module presents commonly encountered polytomous IRT models, describes their properties, and contrasts their defining principles and assumptions. After completing this module, the reader should have a sound understating of what a polytomous IRT model is, the manner in which the equations of the models are generated from the model's underlying step functions, how widely used polytomous IRT models differ with respect to their definitional properties, and how to interpret the parameters of polytomous IRT models.  相似文献