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   

Promoting a participatory convergence in a Spanish context: an inter-university action research project using visual narrative     

Elia Fernández-Díaz  Carlos Rodríguez-Hoyos  Adelina Calvo Salvador  Gloria Braga Blanco  Lorea Fernández-Olaskoaga  Prudencia Gutiérrez-Esteban 《Educational Action Research》2019,27(3):362-378

ABSTRACT

This article focuses on the deconstruction of an inter-university action research project that has allowed us to rethink our teaching and research, questioning the social, political and ethical dimensions of the university. Following the pre-assembly proposal to promote participatory convergence, organized within the framework of the 1^st Global Assembly for Knowledge Democracy (2017), an action research process was implemented in order to generate systematic inquiry around the current situation of the university and the need to act and rethink our commitment to promoting changes in this context. We have reflected on the meaning of democratization, rethinking the pedagogical relationship with our students and how we critically commit them to promote activism. We generated an environment where we look for the meaning of our practices by means of a visual narrative which has enabled us to weave and identify our own biography and become aware of where we are and why we act in one way or another. We have also focused on the search for the meaning of our actions in relation to the community we belong to and how to deal with the challenges of social justice, encouraging collaboration with other networks in a wider inter-university framework.  相似文献   

Addressing quality challenges in the private university sector in Bangladesh: from policy formulation to institutional implementation     

Gerardo Blanco Ramírez  H. M. Jahirul Haque 《Quality in Higher Education》2016,22(2):139-151

Private higher education is growing, especially in developing and transitioning countries. Rapid growth frequently comes with concerns about quality. This article explores challenges and opportunities for higher education quality among private universities in Bangladesh. By presenting a vertical case study that explores interactions among actors at the institutional, national and global spheres, the authors argue for the need of developing quality standards that respond to the local realities of developing and transitioning countries. It is also argued that self-regulation among private universities is likely the most effective pathway for improvement. Bangladesh presents an ideal case for analysis given the rapid growth that higher education has experienced in the last 20 years in that country and given the current policy junction as Bangladesh begins to implement a newly developed quality assurance system. Other countries in the region in early stages of developing quality assurance and accountability systems may benefit from the findings of this study.  相似文献   

The chimera of the competency-based approach to teaching mathematics: a study of carpentry purchases for home projects     

Diego-Mantecón  José Manuel  Haro  Elena  Blanco  Teresa F.  Romo-Vázquez  Avenilde 《Educational Studies in Mathematics》2021,107(2):339-357

Educational Studies in Mathematics - The competency-based approach conceives mathematics as a necessary tool for dealing with daily-life tasks. Many studies have focused on examining the low math...  相似文献   

Pawns in a Chess Game     

Gloria García González 《Media History》2015,21(4):412-425

The Spanish Service was established in June 1939, two months after the end of the civil war in Spain and shortly before the start of the Second World War. Its implementation was strongly affected by these conflicts in the context of new international relations. Therefore, this study of the Spanish Service during 1939–1945 allows not only a better understanding of the communicational strategies developed by the BBC, but also of the complex Anglo-Spanish relations and the important role played by the Spanish-language broadcasts therein. The study is mainly based on archival documents from the National Archives in London and memoirs.  相似文献   

Family dynamics and cochlear implant: a case study / Dinámica familiar e implante coclear: estudio de casos     

José Mª Fernández-Batanero  Gema Blanco 《Infancia y Aprendizaje》2015,38(1):30-66

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Translating quality in higher education: US approaches to accreditation of institutions from around the world     

Gerardo Blanco Ramírez 《Assessment & Evaluation in Higher Education》2015,40(7):943-957

This article reports on findings from a sociolinguistic qualitative study exploring inter-discursive relations manifested in the approaches and strategies that regional accrediting agencies in the United States utilise when recognising foreign universities. Even as most countries have developed national quality assurance systems and whilst international rankings comparing institutions globally are available, a growing number of universities around the world seek recognition from American regional agencies. By comparing policy statements, manuals, guidelines and other documents, and after interviewing top-level officers at US accrediting agencies, this study makes explicit the assumptions and central discourses associated with US accreditation of non-US institutions of higher education, from the accreditors’ perspective. Following constant comparison and cultural critical discourse analysis, the study reveals concerns about the equivalency of quality, emphasis on capacity building and reluctance toward adapting US standards. An interest in building international partnerships, in order to respond to globalisation, is also identified.  相似文献   

The Impact of an Erasmus Placement in Students’ Perception of their Intercultural Communicative Competence     

Ramiro Durán Martínez  Gloria Gutiérrez  Fernando Beltrán Llavador  Fernando Martínez Abad 《Journal of Intercultural Communication Research》2016,45(4):338-354

Pre- and post-questionnaires answered by UK Nottingham Trent University (NTU) and Spain’s University of Salamanca (USAL) students on their placement abroad support a comparative analysis of its impact on their intercultural communicative competence, comprising the awareness, attitude, skills and knowledge dimensions. NTU students started their placements with better results in them all. Yet, while both groups completed their stay with a similarly increased awareness, the knowledge and skills of the USAL group matched the results of NTU students and, whereas the scores of the attitude dimension towards the host country of NTU students did not increase significantly, those of USAL students decreased.  相似文献   

Inaccuracy as a privacy-enhancing tool     

Gloria González Fuster 《Ethics and Information Technology》2010,12(1):87-95

The accuracy principle is one of the key standards of informational privacy. It epitomises the obligation for those processing personal data to keep their records accurate and up-to-date, with the aim of protecting individuals from unfair decisions. Currently, however, different practices being put in place in order to enhance the protection of individuals appear to deliberately rely on the use of ‘inaccurate’ personal information. This article explores such practices and tries to assess their potential for privacy protection, giving particular attention to their legal implications and to related ethical issues. Ultimately, it suggests that the use of ‘inaccurate’ data can potentially play a useful role to preserve the informational autonomy of the individual, and that any understandings of privacy or personal data protection that would tend to unduly limit such potential should be critically questioned.  相似文献   

Teaching Prospect Theory with the Deal or No Deal Game Show     

Ardith Baker  Teresa Bittner  Christos Makrigeorgis  Gloria Johnson  Joseph Haefner 《Teaching Statistics》2010,32(3):81-87

Recent evidence indicates that decision makers are more sensitive to potential losses than gains. Loss aversion psychology has led behavioural economists to look beyond expected utility by developing prospect theory. We demonstrate this theory using the Deal or No Deal game show.  相似文献