Tracking user-role evolution via topic modeling in community question answering     

Chaogang Fu 《Information processing & management》2019,56(6):102075

Community question answering (CQA) services that enable users to ask and answer questions are popular on the internet. Each user can simultaneously play the roles of asker and answerer. Some work has aimed to model the roles of users for potential applications in CQA. However, the dynamic characteristics of user roles have not been addressed. User roles vary over time. This paper explores user representation by tracking user-role evolution, which could enable several potential applications in CQA, such as question recommendation. We believe this paper is the first to track user-role evolution and investigate its influence on the performance of question recommendation in CQA. Moreover, we propose a time-aware role model (TRM) to effectively track user-role evolution. With different independence assumptions, two variants of TRM are developed. Finally, we present the TRM-based approach to question recommendation, which provides a mechanism to naturally integrate the user-role evolution with content relevance between the answerer and the question into a unified probabilistic framework. Experiments using real-world data from Stack Overflow show that (1) the TRM is valid for tracking user-role evolution, and (2) compared with baselines utilizing role based methods, our TRM-based approach consistently and significantly improves the performance of question recommendation. Hence, our approach could enable several potential applications in CQA.  相似文献   

基于多系数保角变换法的船舶垂荡纵摇运动仿真     

张腾  任俊生  范小晴  张秀凤 《上海海事大学学报》2019,40(3):51-56

为给航海模拟器建立实用可靠的船舶在波浪中运动的数学模型,基于二维线性势流理论,采用多系数保角变换法对每个船舶横剖面进行高精度拟合,计算各个横剖面的水动力系数和波浪激励力,利用Visual Studio自主开发出船舶在规则波中的纵向运动数值模拟程序。为验证这个数值模拟程序的可靠性,对S175集装箱船在迎浪中运动的幅值响应因子(response amplitude operator, RAO)进行数值计算。结果表明:当弗劳德数为0.275时,RAO计算结果在大部分频率范围内与试验结果吻合良好。因此,这个数值模拟程序能准确地对船舶在波浪中的运动时历进行仿真。  相似文献   

Effect of different loading conditions on running mechanics at different velocities     

Germán Carretero-Navarro  Doménico Cherubini  Wolfgang Taube 《European Journal of Sport Science》2019,19(5):595-602

Weighted vests are widely used to improve running economy and performance. However, it is not well-studied how running mechanics are adapted to counteract the higher peak vertical ground reaction forces (Fpeak) while running with such a device. Therefore, the present study aimed to investigate the effects of different loading conditions on running mechanics at different velocities. Thirteen subjects participated in two separate sessions one week apart. In the first session, maximal aerobic speed (MAS) was determined through a maximal incremental running test while in the second session, they were instructed to run during one minute under different loading (0%, +10% and +20% of body mass [BM]) and velocity (60%, 80% and 100% of MAS) conditions in a random order. Spatiotemporal data were recorded and then running mechanics modelled using the spring-mass model. The main results indicated that vertical and leg stiffness (Kvert and Kleg, respectively) were increased (P?P?>?.05) when load was changed. At the same time, alterations of the running kinematics were observed such as longer contact times, reduced flight times, stride frequencies and step lengths, as well as an increase of the centre of mass dynamics. Based on these results it is assumed that runners maintain a certain stiffness level for each velocity despite different loading conditions. As a consequence, Fpeak increases and this probably causes spatiotemporal adjustments in the movement kinematics.  相似文献   

掺混生物柴油对6135Aca型柴油机NO_x排放的影响机理     

刘杰  魏立江  魏海军 《上海海事大学学报》2019,40(3):111-115

为探究船舶柴油机排放的NO_x中各成分的主要生成机理,基于6135Aca型柴油机,利用AVL Fire建立仿真模型,探究掺混生物柴油在不同负荷下对NO_x成分之间转换的影响机理。结果显示:柴油机排放的NO_2主要通过HO_2氧化NO生成,且高温和氧质量分数会影响NO_2的生成,其中高温会抑制NO_2的生成,氧质量分数增加会促进NO_2的生成;掺混生物柴油和增加负荷会使喷雾贯穿距增大,高温区域增加,从而抑制NO_2生成;掺混生物柴油使得燃烧室内氧含量增加,进而HO_2量增加促进NO_2生成;掺混比例较小时,NO_2主要受高温区域影响,当掺混到达一定比例时贯穿距不再增大,这时NO_2主要受氧含量影响。本文得到的NO_2生成机理,对降低NO_x中NO_2的排放比例有一定指导意义。  相似文献   

Reliably Assessing Growth with Longitudinal Diagnostic Classification Models     

Matthew J. Madison 《Educational Measurement》2019,38(2):68-78

Recent advances have enabled diagnostic classification models (DCMs) to accommodate longitudinal data. These longitudinal DCMs were developed to study how examinees change, or transition, between different attribute mastery statuses over time. This study examines using longitudinal DCMs as an approach to assessing growth and serves three purposes: (1) to define and evaluate two reliability measures to be used in the application of longitudinal DCMs; (2) through simulation, demonstrate that longitudinal DCM growth estimates have increased reliability compared to longitudinal item response theory models; and (3) through an empirical analysis, illustrate the practical and interpretive benefits of longitudinal DCMs. A discussion describes how longitudinal DCMs can be used as practical and reliable psychometric models when categorical and criterion‐referenced interpretations of growth are desired.  相似文献   

Paternal support for child sexual abuse victims: A qualitative study     

《Child abuse & neglect》2019

BackgroundThe current state of knowledge regarding the role of non-offending fathers in supporting their sexually abused children is very scarce.ObjectiveThe objective of this study is to further our understanding of fathers’ roles following disclosure of their children’s sexual abuse (SA) by evaluating fathers’ perceptions of the impact of disclosure on their involvement and support of their children.Participants and methodThis qualitative study relies on individual semi-structured interviews conducted with 17 fathers of allegedly abused children.ResultsInductive thematic analysis first highlighted that some reported a period of disengagement from the child during which they put into question their role and attitudes, followed by a period of re-involvement. This period of difficulties experienced by some fathers in regard to their involvement towards their children was due to either their own important psychological distress, their ambivalence towards their child or even because of feelings of uneasiness experienced during physical contact with them. Despite this, findings indicate the presence of thoughts and attitudes that suggest children are a source of concern for fathers. The four forms of abuse-specific support previously observed among mothers (believing the child, seeking out professional services, protecting him/her from the offender, supporting him/her emotionally) were also observed among fathers. In accordance with the activation theory, a form of support specific to fathers, namely, encouraging the child to open up to and explore the world outside the family, thereby, fostering the child’s self-esteem development, was observed and constitutes a relevant finding.ConclusionClinical and empirical implications are discussed.  相似文献   

石膏/蚯蚓粪肥对赤泥团聚体结构稳定性的影响     

王琼丽  叶羽真  薛生国  江钧  朱锋  田桃 《中国科学院大学学报》2019,36(4):530-536

赤泥是氧化铝工业生产过程中排放的高碱性固体废弃物，迄今尚无经济有效的处置方法。以华中地区某堆场赤泥为研究对象，通过土培实验研究改良剂（石膏、蚯蚓粪肥、石膏+蚯蚓粪肥）对赤泥团聚体稳定性的影响。结果表明：石膏的添加能显著降低赤泥pH，而蚯蚓粪肥能显著增加赤泥有机碳含量。土培60 d时，石膏添加后赤泥pH由10.54降到8.75，蚯蚓粪肥添加后赤泥有机碳含量由3.54 g·kg^-1增加至14.31 g·kg^-1。土培180 d时，石膏、蚯蚓粪肥、石膏+蚯蚓粪肥添加后赤泥水稳性团聚体含量由12.04%分别增加到23.49%、29.24%、33.94%；团聚体平均重量直径由0.15 mm分别增加到0.26、0.30、0.34 mm；可蚀性因子由0.36分别降低到0.31、0.30、0.29。石膏和蚯蚓粪肥的添加促进水稳性团聚体形成，提高赤泥团聚体稳定性。基质改良对赤泥团聚体稳定性的影响效果依次为：石膏+蚯蚓粪肥 > 蚯蚓粪肥 > 石膏。研究结果对赤泥土壤化处置和规模化消纳研究有科学参考意义。  相似文献   

工作资源对高校图书馆员敬业度影响机制的实证研究     

康超群  杨晴 《图书情报工作》2019,63(17):69-76

[目的/意义]探讨工作资源对高校图书馆员敬业度的影响与机制，以期为高校图书馆实施人力资源管理和提升图书馆员的敬业度提供参考。[方法/过程]选取湖南各高校图书馆的358名馆员为研究对象，考察工作资源对高校图书馆员敬业度的预测作用以及心理资本与组织承诺在两者之间的中介作用。[结果/结论]描述性统计与差异分析、相关分析和逐步回归分析的结果表明，不同性别的高校图书馆员在组织承诺量表得分上存在显著性差异，男性馆员组织承诺得分显著高于女性，不同性别馆员在其余得分上均不存在显著性差异。不同婚姻、年龄、学历、职位、职称者在各量表得分上均不存在显著性差异。高校图书馆员工作资源、心理资本、组织承诺与敬业度的两两相关都达到统计显著性水平。工作资源对高校图书馆员的敬业度具有正向预测作用，心理资本和组织承诺能够在工作资源对高校图书馆员敬业度的影响中起部分中介作用。丰富高校图书馆员工作资源，增进其组织支持感，增强其心理资本和组织承诺，是促进高校图书馆员敬业度提升的有效路径。  相似文献   

An extension of the technology acceptance model in the big data analytics system implementation environment     

Surabhi Verma  Som Sekhar Bhattacharyya  Saurav Kumar 《Information processing & management》2018,54(5):791-806

Research on the adoption of systems for big data analytics has drawn enormous attention in Information Systems research. This study extends big data analytics adoption research by examining the effects of system characteristics on the attitude of managers towards the usage of big data analytics systems. A research model has been proposed in this study based on an extensive review of literature pertaining to the Technology Acceptance Model, with further validation by a survey of 150 big data analytics users. Results of this survey confirm that characteristics of the big data analytics system have significant direct and indirect effects on belief in the benefits of big data analytics systems and perceived usefulness, attitude and adoption. Moreover, there are mediation effects that exist among the system characteristics, benefits of big data analytics systems, perceived usefulness and the attitude towards using big data analytics system. This study expands the existing body of knowledge on the adoption of big data analytics systems, and benefits big data analytics providers and vendors while helping in the formulation of their business models.  相似文献   

Online social viewing: Cross-cultural adoption and uses of bullet-screen videos     

Anan Wan  Leigh Moscowitz  Linwan Wu 《Journal of International and Intercultural Communication》2020,13(3):197-215

ABSTRACT

Bullet-screen technology, an innovative way of interacting with online videos, allows viewers to contribute comments that simultaneously appear over videos. Popular in East Asia, the technology is making its way to American audiences. This study employed a comparative qualitative focus group approach to explore how American and Chinese viewers responded to and interacted with this new format of online videos. Three themes emerge from this investigation: (1) the unique affordances of this technology; (2) barriers to adoption and usage; and (3) cultural differences that impact the user experience. The theoretical and practical implications for bullet-screen technologies are discussed.  相似文献