Proposal for a cross layer scheme for real-time wireless video

INTRODUCTION Increase in wireless system capacity through 3G services and innovative low bit rate video coding techniques have made it possible to have mobile multimedia services on hand-held systems. High quality real-time multimedia services are slowly be- ing deployed on hand-held systems. However large scale deployment at low cost is still to be realized due to technological challenges such as stringent power control under severely fading environments and the susceptibility of high qu…     

Algebraic Generalization Strategies Used by Kuwaiti Pre-service Teachers

This study reports on the algebraic generalization strategies used by elementary and middle/high school pre-service mathematics teachers in Kuwait. They were presented with 9 tasks that involved linear, exponential, and quadratic situations. The results showed that these pre-service teachers had difficulty in generalizing algebraic rules in all 3 types of tasks. The most difficult problems were those involving exponents; they seemed to confuse exponential growth with the multiplication of n. Although they used several strategies such as explicit, recursive, and chunking, they tended to rely on explicit reasoning. They saw the explicit rule as a quick and easy rule to be used. In order to improve students’ understanding of algebraic reasoning, we must improve the understating of generalization. Teachers’ programs should put more emphasis on the type of content that teachers need to learn rather than on how much mathematics credits teachers need.     

The influence of history of science courses on students' views of nature of science

This study (a) assessed the influence of three history of science (HOS) courses on college students' and preservice science teachers' conceptions of nature of science (NOS), (b) examined whether participants who entered the investigated courses with a conceptual framework consistent with contemporary NOS views achieved more elaborate NOS understandings, and (c) explored the aspects of the participant HOS courses that rendered them more “effective” in influencing students' views. Participants were 166 undergraduate and graduate students and 15 preservice secondary science teachers. An open‐ended questionnaire in conjunction with individual interviews, was used to assess participants' pre‐ and postinstruction NOS views. Almost all participants held inadequate views of several NOS aspects at the outset of the study. Very few and limited changes in participants' views were evident at the conclusion of the courses. Change was evident in the views of relatively more participants, especially preservice science teachers, who entered the HOS courses with frameworks that were somewhat consistent with current NOS views. Moreover, explicitly addressing certain NOS aspects rendered the HOS courses relatively more effective in enhancing participants' NOS views. The results of this study do not lend empirical support to the intuitively appealing assumption held by many science educators that coursework in HOS will necessarily enhance students' and preservice science teachers' NOS views. However, explicitly addressing specific NOS aspects might enhance the effectiveness of HOS courses in this regard. Moreover, the study suggests that exposing preservice science teachers to explicit NOS instruction in science methods courses prior to their enrollment in HOS courses might increase the likelihood that their NOS views will be changed or enriched as a result of their experiences with HOS. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 1057–1095, 2000     

Towards a competency model: A review of the literature and the competency standards

Competency-based approaches using information and communication technologies have been the main solution of the organization’s expectations in all fields (public and private) to increase the products’ quality and employees’ capacity. Furthermore, the concept of competency can have several different definitions, which may make it difficult to model. As a result, without a good representation of the knowledge and competency and reusable definitions of competence, an e- Learning system will be unable to adapt to its users, to personalize learning activities. In this paper, we present a view of some important competency definitions and the main competency specifications, like the HR-XML specification (Human Resources XML), and the IMS Reusable Definition of Competency or Educational Objective (IMS RDCEO). Moreover, we suggest a competency model for training and education based on these specifications.     

Why We Watch: Factors Affecting Exposure to Tragic Television News

This study explored the reasons people expose themselves to news depicting tragic events. A total of 376 undergraduates completed anonymous questionnaires about their responses to news coverage of the events of September 11. The study examined the extent to which individual differences in empathy gave rise to news viewing motives (surveillance, reassurance, curiosity), and how these variables, as well as negative emotional responses (anger, sadness, fear), were related to news interest and exposure. Both empathy and emotional responses were associated in predictable ways with interest in news coverage and selective exposure to specific types of news stories (e.g., casualty news, positive news). The results demonstrate that considering affective motivations can enrich our understanding of how and why people use news media. Limitations and suggestions for future research are discussed.     

Factors Influencing Schoolchildren's Responses to a Questionnaire in Wildlife Conservation Education

Questionnaires are important tools for assessing attitudes regarding conservation issues. However, they are not easily comparable and their reliability has been insufficiently assessed. We examined factors influencing responses to open- and closed-ended questions about animal conservation to more than 600 schoolchildren (9 years old on average). We analysed the level of understanding, controllable (e.g. sample size) and less controllable factors (e.g. affectivity). Most children responded appropriately to the questions, but subtle changes in the phrasing influenced the answers. Affectivity towards endearing species and spontaneity also influenced the responses whereas small sample sizes (～50 children) provided relatively stable patterns. Overall, we suggest that standardization of questionnaires administered over large spatial and time scales is needed to accurately assess children's attitudes towards conservation issues.