Revisiting the cluster-based paradigm for implicit search result diversification     

Hai-Tao Yu  Adam Jatowt  Roi Blanco  Hideo Joho  Joemon M. Jose  Long Chen  Fajie Yuan 《Information processing & management》2018,54(4):507-528

To cope with ambiguous and/or underspecified queries, search result diversification (SRD) is a key technique that has attracted a lot of attention. This paper focuses on implicit SRD, where the subtopics underlying a query are unknown. Many existing methods appeal to the greedy strategy for generating diversified results. A common practice is using a heuristic criterion for making the locally optimal choice at each round. As a result, it is difficult to know whether the failures are caused by the optimization criterion or the setting of parameters. Different from previous studies, we formulate implicit SRD as a process of selecting and ranking k exemplar documents through integer linear programming (ILP). The key idea is that: for a specific query, we expect to maximize the overall relevance of the k exemplar documents. Meanwhile, we wish to maximize the representativeness of the selected exemplar documents with respect to the non-selected documents. Intuitively, if the selected exemplar documents concisely represent the entire set of documents, the novelty and diversity will naturally arise. Moreover, we propose two approaches ILP4ID (Integer Linear Programming for Implicit SRD) and AP4ID (Affinity Propagation for Implicit SRD) for solving the proposed formulation of implicit SRD. In particular, ILP4ID appeals to the strategy of bound-and-branch and is able to obtain the optimal solution. AP4ID being an approximate method transforms the target problem as a maximum-a-posteriori inference problem, and the message passing algorithm is adopted to find the solution. Furthermore, we investigate the differences and connections between the proposed models and prior models by casting them as different variants of the cluster-based paradigm for implicit SRD. To validate the effectiveness and efficiency of the proposed approaches, we conduct a series of experiments on four benchmark TREC diversity collections. The experimental results demonstrate that: (1) The proposed methods, especially ILP4ID, can achieve substantially improved performance over the state-of-the-art unsupervised methods for implicit SRD. (2) The initial runs, the number of input documents, query types, the ways of computing document similarity, the pre-defined cluster number and the optimization algorithm significantly affect the performance of diversification models. Careful examinations of these factors are highly recommended in the development of implicit SRD methods. Based on the in-depth study of different types of methods for implicit SRD, we provide additional insight into the cluster-based paradigm for implicit SRD. In particular, how the methods relying on greedy strategies impact the performance of implicit SRD, and how a particular diversification model should be fine-tuned.  相似文献   

Optimised force-velocity training during pre-season enhances physical performance in professional rugby league players     

Adam Simpson  Mark Waldron  Emily Cushion  Jamie Tallent 《Journal of sports sciences》2021,39(1):91-100

ABSTRACT

The effectiveness of 8-week force-velocity optimised training was assessed in highly trained professional rugby league athletes. Players (age 24 ± 3 years; body mass 94.9 ± 21.6 kg; height 181.3 ± 6.0 cm) were strength-matched and assigned to a force-velocity optimised group (OP; n = 15) or a general strength-power group (GP; n = 14). Tests included 10-m, 20-m sprints, 3 repetition-maximum squat and squat jumps over five load conditions to ascertain vertical force-velocity relationship. ANCOVA revealed there was a group effect for force-velocity deficit (P < 0.001), with the OP two-fold greater than the GP group (OP pre: 51.13 ± 31.42%, post: 62.26 ± 31.45%, GP pre: 33.00 ± 19.60%, post: 31.14 ± 31.45%, P < 0.001). There were further group effects for 3RM squat (OP pre: 151.17 ± 22.95 kg, post: 162.17 ± 24.16 kg, GP pre: 156.43 ± 25.07 kg, post: 163.39 ± 25.39 kg, P < 0.001), peak power (OP pre: 3195 ± 949 W, post: 3552 ± 1033 W, GP pre: 3468 ± 911 W, post: 3591 ± 936 W, P < 0.001), and SJ (OP pre: 39.79 ± 7.80 cm, post: 42.69 ± 7.83 cm, GP pre: 40.44 ± 6.23 cm, post: 41.14 ± 5.66 cm, P < 0.001). Prescribing F-V deficit training is superior for improving physical performance within highly trained RL players.  相似文献   

Coming Back from Disaster: Progress to Date and Next Steps at Elliot Lake Public Library     

Adam Stewart 《Public Library Quarterly》2017,36(3):228-243

In this article, I do two things. First, I describe and evaluate progress that has been made to date on implementing five recommendations made by the author to the leadership of Elliot Lake Public Library in 2014, intended to assist in disaster recovery efforts following the destruction of the library in an anthropogenic disaster in 2012. Second, I provide three revised recommendations, this time intended to assist library leadership address some continuing challenges that are preventing the complete recovery of the library, and ultimately, negatively impacting the effectiveness of the library within the community.  相似文献   

Relationships between Media Freedom and Social Capital,Evaluating Newspaper Responses to Internet Competition,and Audience Demand for Television Broadcasts of International Football Games     

Hugh J. Martin  Adam D. Rennhoff 《Journal of Media Economics》2017,30(1):1-2

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Toward collaborator selection and determination of data ownership and publication authorship in research collaborations     

Besiki Stvilia  Charles C. Hinnant  Shuheng Wu  Adam Worrall  Dong Joon Lee  Kathleen Burnett  Gary Burnett  Michelle M. Kazmer  Paul F. Marty 《Library & information science research》2017,39(2):85-97

This study examined factors that might affect researchers' willingness to collaborate with a specific researcher and the priorities given to those factors. In addition, it investigated how researchers determined the ownership of collaborative project data and how they determined the order of authorship on collaborative publications in condensed matter physics. In general, researchers rated their intrinsic motivations the highest, such as the quality of ideas a potential collaborator might have and their satisfaction with a past collaboration, followed by their extrinsic motivations, such as the complementary knowledge, skills, or resources the collaborator could provide. In addition, researchers who had a greater number of collaborative projects and researchers who had served as a project PI or co-PI valued the deep-level, personality-related characteristics of a collaborator higher than did those who had not. Younger researchers were more risk averse and more concerned with a collaborator's reputation and the possible cost of a collaboration decision. Additionally, younger researchers indicated more often than older researchers that they did not know whether their project teams followed any rules or norms or engaged in negotiation to determine the order of authorship on collaborative publications.  相似文献   

Working Together: Integrating Computational Modeling Approaches to Investigate Complex Phenomena     

Bielik  Tom  Fonio  Ehud  Feinerman  Ofer  Duncan  Ravit Golan  Levy  Sharona T. 《Journal of Science Education and Technology》2021,30(1):40-57

Journal of Science Education and Technology - Complex systems are made up of many entities, whose interactions emerge into distinct collective patterns. Computational modeling platforms can provide...  相似文献   

Phil Foster at Albany     

Daniel C. Levy 《Prospects》2008,38(4):565-567

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University Counselling Service Utilisation by Local and International Students and User Characteristics: A Review     

Adam Raunic  Sophia Xenos 《International journal for the advancement of counseling》2008,30(4):262-267

This paper reviews research on students’ usage of university counselling services across countries and their demographic and psychological characteristics. In doing so, emphasis is given to reported distinctions between local and international university students. Utilisation rates, encouraging factors and barriers to utilisation, presenting problems, and methodological problems with existing studies are each examined. The findings suggest that only a minority of between 2% and 4% of university students access such services, with females being more likely to use them than males. International students in particular underutilise these services, and this is primarily due to such students’ preference for seeking help from family or friends over outside sources. When students do seek assistance, their presenting issues most commonly involve symptoms of depression or anxiety, as well as academic and relationship difficulties.  相似文献   

The antecedents of teacher satisfaction with professional development programs     

Adam E. Nir  Ronit Bogler 《Teaching and Teacher Education》2008

Literature has shown that on-the-job professional development programs are most beneficial when they are long-term, focused on students’ learning, and linked to the curricula. We hypothesized that the higher the control teachers have over job professional development processes, and the greater the resemblance of these processes to the typical teaching culture in classrooms, the greater the teachers’ satisfaction with job professional development processes. The findings of this study demonstrate that the main factors affecting teachers’ satisfaction with the instructional programs are related to their desire to maintain instructional processes “close to home”, and to shape these processes in accordance with their needs and expectations. The implications of the study are discussed with relation to decision-makers in the school setting and at the local authorities’ level.  相似文献   

Incorporating Uncertainty Into Parallel Analysis for Choosing the Number of Factors via Bayesian Methods     

Roy Levy  Yan Xia  Samuel B. Green 《Educational and psychological measurement》2021,81(3):466

A number of psychometricians have suggested that parallel analysis (PA) tends to yield more accurate results in determining the number of factors in comparison with other statistical methods. Nevertheless, all too often PA can suggest an incorrect number of factors, particularly in statistically unfavorable conditions (e.g., small sample sizes and low factor loadings). Because of this, researchers have recommended using multiple methods to make judgments about the number of factors to extract. Implicit in this recommendation is that, when the number of factors is chosen based on PA, uncertainty nevertheless exists. We propose a Bayesian parallel analysis (B-PA) method to incorporate the uncertainty with decisions about the number of factors. B-PA yields a probability distribution for the various possible numbers of factors. We implement and compare B-PA with a frequentist approach, revised parallel analysis (R-PA), in the contexts of real and simulated data. Results show that B-PA provides relevant information regarding the uncertainty in determining the number of factors, particularly under conditions with small sample sizes, low factor loadings, and less distinguishable factors. Even if the indicated number of factors with the highest probability is incorrect, B-PA can show a sizable probability of retaining the correct number of factors. Interestingly, when the mode of the distribution of the probabilities associated with different numbers of factors was treated as the number of factors to retain, B-PA was somewhat more accurate than R-PA in a majority of the conditions.  相似文献