Topic-independent modeling of user knowledge in informational search sessions     

Yu  Ran  Tang  Rui  Rokicki  Markus  Gadiraju  Ujwal  Dietze  Stefan 《Information Retrieval》2021,24(3):240-268

Information Retrieval Journal - Web search is among the most frequent online activities. In this context, widespread informational queries entail user intentions to obtain knowledge with respect to...  相似文献   

The impact of graph symmetry on the number of driver nodes in complex networks     

Hossein Parastvand  Airlie Chapman  Octavian Bass  Stefan Lachowicz 《Journal of The Franklin Institute》2021,358(7):3919-3942

This study investigates on a strong correlation between complex network (CN) controllability (characterized by the number of required driver nodes) and graph symmetry (described by automorphism groups) in undirected and unweighted networks. Based on the properties of permutation products of elementary automorphisms, novel necessary conditions for CN controllability are presented which are computationally more effective than previous method. In addition, a novel index of symmetry is proposed upon which a more meaningful understanding of symmetry impact on CN controllability can be comprehended. Based on this new index, a modification strategy is suggested aiming to satisfy CN controllability with a lower number of driver nodes. The study shows that the proposed modification approach can result in a minimal set of driver nodes with a reasonable computational complexity. Further, the critical components of complex networks, in terms of their impact on the number of required driver nodes, are identified. The results of the proposed methodologies have been verified for several synthetic and real test systems including small, medium, and large power networks.  相似文献   

Introduction to special issue on the second international conference on the theory of information retrieval     

Leif Azzopardi  Dawei Song  Gabriella Kazai  Stephen Robertson  Stefan Rüger  Milad Shokouhi  Emine Yilmaz 《Information Retrieval》2011,14(1):1-4

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Manfred Broy und Stefan J?hnichen 《Informatik - Forschung und Entwicklung》1997,12(3):157-160

Zusammenfassung. Von Februar 1990 bis Juni 1994 arbeiteten 15 Partner im Bmft-Verbundprojekt Korso an der Weiterentwicklung und Umsetzung formaler Software-Entwicklungsmethoden. Dieser Artikel gibt einen überblick über die Ziele und die wesentlichen Ergebnisse des Projekts.  相似文献   

Explaining Constraint Interaction: How to Interpret Estimated Model Parameters Under Alternative Scaling Methods     

Stefan Klößner 《Structural equation modeling》2019,26(1):143-155

In this paper, we explain the reasons behind constraint interaction, which is the phenomenon that the results of testing equality constraints may depend heavily on the scaling method used. We find that the scaling methods interfere with the testing procedures because scaling methods determine which transformations of population quantities model parameters actually estimate. We therefore also develop rules on how to correctly interpret estimates of model parameters under alternative scaling methods.  相似文献   

Procedure and reliability of conditioned respiratory suppression     

S. Stefan Soltysik  Nancy K. Dess  W. Jeffrey Wilson  John A. Matochik  Steve Berg 《Learning & behavior》1988,16(2):177-184

Changes in respiration amplitude, respiration rate, and heart rate in response to a conditioned signal for shock were measured concurrently in kittens and adult cats. The data were analyzed with respect to qualitative and quantitative variability across trials and subjects; correlation among measures; skewness; and kurtosis. Suppression of respiration amplitude was the most reliable response across trials and subjects, with increases in respiration rate second and heart rate by far the least reliable. Correlations between each pair of measures were moderate. Respiration-amplitude responses were negatively skewed, but this deviation from normality was moderate and consistent across subjects. The measurement of conditioned respiratory suppression is a viable addition or alternative to the conditioned emotional response procedure in studies of classically conditioned fear.  相似文献   

Critically Reflecting on the Origins,Evolution, and Impact of the Cattell-Horn-Carroll (CHC) Model     

Ryan J. McGill  Stefan C. Dombrowski 《教育实用测度》2019,32(3):216-231

ABSTRACT

The Cattell-Horn-Carroll (CHC) model presently serves as a blueprint for both test development and a taxonomy for clinical interpretation of modern tests of cognitive ability. Accordingly, the trend among test publishers has been toward creating tests that provide users with an ever-increasing array of scores that comport with CHC. However, an accumulating body of independent research on modern intelligence tests has questioned many instruments’ alignment with the CHC model. To shed potential insight on these discrepancies, we review the developmental history of CHC and its numerous modifications from 1997 to the present. Next, we identify and discuss several potential limitations in the CHC literature that may be responsible for this discrepancy. Finally, we encourage clinicians to consider the extant evidence currently available for engaging in CHC-inspired assessment applications (e.g., XBA, PSW).  相似文献   

The student,the private and the professional role: Students’ social media use     

Pernilla Josefsson  Stefan Hrastinski  Daniel Pargman  Teresa C. Pargman 《Education and Information Technologies》2016,21(6):1583-1594

Research has shown that students perceive a distinct divide between educational and private use of social media. The present study explores this divide by focusing on master students’ perception of roles when using social media in a higher education context. A qualitative method has been used, mainly comprising of analyses of home exams and interviews, which were conducted with students enrolled in the master’s course “Social media technologies”. Results support previous research stating that students perceived a distinct divide between educational and private use of social media, and furthermore provide a more detailed understanding of this divide. The results from the study also indicate that there is yet another type of use: social media as a tool for career-building purposes, or what is labeled as professional use. Implications of social media for use in higher education are described through the analysis of three roles as performed by the individual: the student role in educational settings, the professional role for career-building, and the private role.  相似文献   

A black technician and blue babies     

Timmermans S 《Social studies of science》2003,33(2):197-229

In this paper, I discuss the many contributions of a versatile black technician, Vivien Thomas, to surgical animal research between 1930 and 1979 at Vanderbilt University and Johns Hopkins University. Thomas' experimental work led to a surgical solution for a life-threatening heart defect, called tetralogy of Fallot. Children with this condition lack sufficient oxygenation and were referred to as 'blue babies'. Following Thomas' research trajectory and his relationship with surgeon Dr Alfred Blalock, I review the conditions under which differing expectations towards race and occupation clashed, creating a status dilemma for Thomas. While the torsion originated in the laboratory where technical skills are valued, the research locale also facilitated a temporary, fragile solution for the status dilemma, because it separated Thomas from public view. Yet, Thomas' dexterity as a laboratory researcher enhanced his dilemma, because credit kept eluding him. In order to track the dynamics of race and occupational subordination as lived experience in the laboratory, I argue for an analysis of the process of crediting people for their scientific accomplishments.  相似文献   

Motivational interference in learning: The impact of leisure alternatives on subsequent self-regulation     

Stefan Fries  Franziska Dietz  Sebastian Schmid 《Contemporary educational psychology》2008,33(2):119-133

Students are often obliged to fulfill home assignments for school. While being engaged into such compulsory schooling, learners may be tempted to switch to a leisure alternative. Whenever students pursue the learning task although attractive leisure alternatives are present, thoughts about the missed activity can lead to motivational interference. Thus, self-regulation in learning does not only depend on the learning task itself but also on the dismissed alternatives. In a questionnaire study 704 students (mean age: 13.5) were confronted with hypothetical conflicts between a school activity and a leisure activity. The students envisioned themselves in the course of both activities after the decision. As predicted, self-reported self-regulation depended on the valences of both activities. High valence of the performed activity was related to better self-regulation, whereas high valence of the alternative activity resulted in worse self-regulation.  相似文献