Longitudinal resistance performance of granular ballast beds under cyclic symmetric displacement loading

The longitudinal resistance performance of a granular ballast bed under cyclic symmetric displacement loading was studied based on a full-scale test model of ballast track structures. The change law of the longitudinal resistance characteristics of the ballast bed under variable displacement amplitudes was analyzed. The results show that: the resistance-displacement curves of a granular ballast bed are a set of closed hysteretic curves, indicating obvious energy consumption; a granular ballast bed softens gradually during the cyclic process with constant displacement amplitude, and the residual deformation rate increases nonlinearly with increasing cycle number; the peak value of the longitudinal resistance of lines decreases with increasing cycle number; the cyclic softening of a granular ballast bed is dependent on the displacement amplitude–the higher the displacement, the more severe the cyclic softening will become; after cyclic displacement loading is applied several times, the longitudinal resistance of the bed will degenerate obviously, and the higher the displacement amplitude, the higher the longitudinal resistance attenuation rate of the ballast bed will become.     

Different ways in which students handle chance encounters in the explorative setting of a dice game

The purpose of this study is to investigate the ways in which Swedish seventh grade students (12 and 13 years old) handle chance encounters. Four groups of students working in pairs participated in the study. In the group discussions, which were tape-recorded and fully transcribed, the students were encouraged to explore strategies for winning a specifically designed dice game based on the sum of two dice. The dice game included four different set-ups of dice designed to bring to the fore different aspects of probability modelling and to offer the student the opportunity to encounter small differences in the mathematical structure of the sample space and of the probability distribution between the four different set-ups. The study describes strategies that the students use when confronted with these different set-ups, what their activities imply in terms of resources in handling random phenomena and what the dice game offers in terms of opportunities for learning probability. In order to explain such meaning-making processes the students’ activities are viewed from a perspective that takes into consideration how the students’ understanding varies with their interpretations of the situation they are confronted with, i.e., how they contextualize the different set-ups of the dice game. The results show how the students, during the course of the game, reorganize their interpretations of the mathematical content confronting them, and how a variation of guiding principles becomes the object of exploration. Approaches of extremes and a number model are described as a means for the students to identify and assign probabilities for the total of two dice.     

A novel dependency language model for information retrieval

This paper explores the application of term dependency in information retrieval (IR) and proposes a novel dependency retrieval model. This retrieval model suggests an extension to the existing language modeling (LM) approach to IR by introducing dependency models for both query and document. Relevance between document and query is then evaluated by reference to the Kullback-Leibler divergence between their dependency models. This paper introduces a novel hybrid dependency structure, which allows integration of various forms of dependency within a single framework. A pseudo relevance feedback based method is also introduced for constructing query dependency model. The basic idea is to use query-relevant top-ranking sentences extracted from the top documents at retrieval time as the augmented representation of query, from which the relationships between query terms are identified. A Markov Random Field (MRF) based approach is presented to ensure the relevance of the extracted sentences, which utilizes the association features between query terms within a sentence to evaluate the relevance of each sentence. This dependency retrieval model was compared with other traditional retrieval models. Experiments indicated that it produces significant improvements in retrieval effectiveness.     

Design,development, and implementation of electronic learning environments for collaborative learning

Developments in society and business, and related changes in higher education and lifelong learning, require educators and educational designers or technologists to rethink education. Examples of such changes are the growing importance of achieving complex learning, the integration of learning and work in education, and the need for improved flexibility with regard to time, place, and individual needs. These changes cannot simply be responded to by adding technological solutions implemented according to existing educational approaches. Instead, an integrated view of e-learning is necessary, characterized by the combination of pedagogical, technical, social, and organizational factors. This two-part special issue elaborates on the different characteristics of integrated e-learning, from design through future topics for research. He would like to give special thanks to Jan Elen and Brent Wilson, who took on the task of reviewing and discussing all of the contributions, both at AECT 2003 in Anaheim and for this issue, and J. Michael Spector, Development Editor of this journal, for his faith in all of us.     

Moderators of the interest congruence-occupational outcome relation

Several reasons for the modest relation between interest congruence and occupational outcomes are discussed, but focus is placed on possible moderators of this relation. Specifically individual differences, environmental differences and time are proposed as potential moderators. Overall, it is important to investigate theoretically driven moderators of the congruence-outcome relation to further our knowledge of this area.     

Integrating synchronous and asynchronous internet distributed education for maximum effectiveness

Distributed education delivered via the Internet is a growing practice, with most institutions offering at least course websites and many expanding to full course offerings and even online degree progams. There are two schools of thought with regard to delivery mode: the larger group has focused on asynchronous delivery, accessible at any time via webpages and interactive tutorials and quizzes, while a smaller group advocates synchronous delivery where students are online and interact during class time. This paper summarizes the advantages and disadvantages of the two delivery modes and describes our successful and growing experience of more than a decade using an open source synchronous delivery tool blended with a variety of asynchronous capabilities and classroom instruction. We conclude that a synergistic combination of the two modes with in-person instruction, designed to provide maximum flexibility to the student within the constraints of the subject, offers the best support for student learning. www:     

A Systematic Literature Review of Funding for Higher Education Institutions in Developed Countries

Resource allocation and funding in higher education is crucial to the success of reform and transformation of our higher education system. With a view to identifying trends and best practices in the area, utilizing a method of systematic literature review, we have critically reviewed relevant theories and practices from developed counties that are covered in the scholarly literature published in English in the past 10 years. Our review has revealed: (1) Several universal trends have exerted a decisive impact on resource allocation in higher education, for example, funding reduction and tuition fee increases, performancebased funding, privatization, corporatization, and internationalization; (2) Several theories underpin key research in the area, for example, new institutional economics, resource dependence theory, and political economy; (3) Several controversial issues have made their way into public debate, for example, higher education as a public good or private good, academic capitalism, educational equity, and the role of econometrics.