Variational bayes for modeling score distributions

Empirical modeling of the score distributions associated with retrieved documents is an essential task for many retrieval applications. In this work, we propose modeling the relevant documents’ scores by a mixture of Gaussians and the non-relevant scores by a Gamma distribution. Applying Variational Bayes we automatically trade-off the goodness-of-fit with the complexity of the model. We test our model on traditional retrieval functions and actual search engines submitted to TREC. We demonstrate the utility of our model in inferring precision-recall curves. In all experiments our model outperforms the dominant exponential-Gaussian model.     

Statistical learning for OCR error correction

Modern OCR engines incorporate some form of error correction, typically based on dictionaries. However, there are still residual errors that decrease performance of natural language processing algorithms applied to OCR text. In this paper, we present a statistical learning model for post-processing OCR errors, either in a fully automatic manner or followed by minimal user interaction to further reduce error rate. Our model employs web-scale corpora and integrates a rich set of linguistic features. Through an interdependent learning pipeline, our model produces and continuously refines the error detection and suggestion of candidate corrections. Evaluated on a historical biology book with complex error patterns, our model outperforms various baseline methods in the automatic mode and shows an even greater advantage when involving minimal user interaction. Quantitative analysis of each computational step further suggests that our proposed model is well-suited for handling volatile and complex OCR error patterns, which are beyond the capabilities of error correction incorporated in OCR engines.     

Organised Military Sports of the Hellenic Armed Forces for the Period 1948–1968

The year 1948, as a starting point both of this study and of the organised military sport for Greece, was particularly hectic, since the newly liberated country was embroiled in the Civil War while, simultaneously, it was trying to reconstitute itself. The next two decades were marked by the foundation and the activities of the Higher Coordinating Committee for Sport in the Armed Forces (Anotera Syntonistiki Epitropi Athlitismou Enoplon Dynameon – A.S.E.A.E.D.). This Committee organised and materialised the first steps of the newly established organised sports activities of the Hellenic Armed Forces and evolved as a result, into the Supreme Council for Sport in the Armed Forces (Anotato Symvoulio Athlitismou Enoplon Dynameon) in year 1968. Due to the lack of specific and thorough research on the topic during this era, the purpose of this study was to identify references and the original sources (archives both of the A.S.E.A.E.D. and of the Hellenic National Defense General Staff) and to highlight and reveal the activities of organised Greek military sport, in the organisational field, and the Hellenic Armed Forces' participation in international sports tournaments.     

Incorporating Poeticality into the Teaching of Physics

This study examines how focusing on the notion of ‘poeticality’ (poetical forms) can provide functional insights with respect to the narrativeness of physics teaching. From this perspective, through both a meaning-making and aesthetic approach, this article explores how vehicles such as verse and rhetorical figures—metaphor, irony, litotes, hyperbole, antithesis and paradox—can create written and oral texts for the teaching of physics, using a language with poetic significance. This standpoint exists in parallel with an increasingly acknowledged fact in the field of science education, i.e., that the context and particularly the modes of representation potentially affect students’ comprehension. In this way, science education is allowed to escape the dominance of the cognitive paradigm and to concentrate on the study of students’ conceptualisations in relation to the modalities used to shape meanings.     

A Voyage of Mathematical and Cultural Awareness for Students of Upper Secondary School

Many papers have emphasized the need for and importance of particular examples and the underlying rationale for introducing a historical dimension in mathematics education. This article presents the development and implementation of a project, based on original sources, in a situation where the existing curriculum does not include history. The subject was conic sections and the motivating problems and original work which eventually found resolution in modern concepts. The project was carried out during the school year 2006–2007 with 18 students of a Greek experimental high school 2nd class (11th degree). It was devised as a series of worksheets, separate readings and oral presentations and written essays so that students might appreciate that mathematics evolves under the influence of factors intrinsic and extrinsic to it. Both epistemological and disciplinary issues are taken into account. Even though this work is just one case study, we have found that exposing students directly to primary sources in mathematics contributes greatly to motivation and understanding, and illustrates the nature of mathematics as a discipline and as a human endeavour.     

Using History to Teach Mathematics: The Case of Logarithms

Many authors have discussed the question why we should use the history of mathematics to mathematics education. For example, Fauvel (For Learn Math, 11(2): 3–6, 1991) mentions at least fifteen arguments for applying the history of mathematics in teaching and learning mathematics. Knowing how to introduce history into mathematics lessons is a more difficult step. We found, however, that only a limited number of articles contain instructions on how to use the material, as opposed to numerous general articles suggesting the use of the history of mathematics as a didactical tool. The present article focuses on converting the history of logarithms into material appropriate for teaching students of 11th grade, without any knowledge of calculus. History uncovers that logarithms were invented prior of the exponential function and shows that the logarithms are not an arbitrary product, as is the case when we leap straight in the definition given in all modern textbooks, but they are a response to a problem. We describe step by step the historical evolution of the concept, in a way appropriate for use in class, until the definition of the logarithm as area under the hyperbola. Next, we present the formal development of the theory and define the exponential function. The teaching sequence has been successfully undertaken in two high school classrooms.     

Evaluation parameters for computer-adaptive testing

With the proliferation of computers in test delivery today, adaptive testing has become quite popular, especially when examinees must be classified into two categories (pass/fail, master/nonmaster). Several well‐established organisations have provided standards and guidelines for the design and evaluation of educational and psychological testing. The purpose of this paper was not to repeat the guidelines and standards that exist in the literature but to identify and discuss the main evaluation parameters for a computer‐adaptive test (CAT). A number of parameters should be taken into account when evaluating CAT. Key parameters include utility, validity, reliability, satisfaction, usability, reporting, administration, security, and thoseassociated with adaptivity, item pool, and psychometric theory. These parameters are presented and discussed below and form a proposed evaluation model, Evaluation Model of Computer‐Adaptive Testing.