Group presence in virtual worlds: Supporting collaborative e-learning

Even though e-learning endeavors have significantly proliferated in recent years, current e-learning technologies provide poor support for group-oriented learning. The now popular virtual world's technologies offer a possible solution. Virtual worlds provide the users with a 3D - computer generated shared space in which they can meet and interact through their virtual representations. Virtual worlds are very successful in developing high levels of engagement, presence and group presence in the users. These elements are also desired in educational settings since they are expected to enhance performance. The goal of this research is to test the hypothesis that a virtual world learning environment provides better support for group-oriented collaborative e-learning than other learning environments, because it facilitates the emergence of group presence. To achieve this, a quasi-experimental study was conducted and data was gathered through the use of various survey instruments and a set of collaborative tasks assigned to the participants. Data was gathered on the dependent variables: Engagement, Group Presence, Individual Presence, Perceived Individual Presence, Perceived Group Presence and Performance. The data was analyzed using the statistical procedures of Factor Analysis, Path Analysis, Analysis of Variance (ANOVA) and Multivariate Analysis of Variance (MANOVA). The study provides support for the hypothesis. The results also show that virtual world learning environments are better than other learning environments in supporting the development of all the dependent variables. It also shows that while only Individual Presence has a significant direct effect on Performance; it is highly correlated with both Engagement and Group Presence. This suggests that these are also important in regards to performance. Developers of e-learning endeavors and educators should incorporate virtual world technologies in their efforts in order to take advantage of the benefit they provide for e-learning group collaboration.

Instructional change through collaboration and reflection

The purpose of this study was to investigate the effectiveness of the Facilitator-Collaborative-Reflective Model, a strategic plan for changing teachers' practices and beliefs, on a selected group of middle school teachers. This model of staff development training was based on Corey's (1953) Cooperative-Action-Research Model and Anders and Richardson (1994) Collaborative-Reflective Model. It supports the notion that earning a teachers' commitment to change by focusing on collaboration, reflection and the normative-re-educative process aids in altering teachers' beliefs and practices especially crucial to the change process. The year-long training provided for reflection, inquiry, and learning that was useful to teachers as they pursued their goals with their students. The lead teacher, as a change agent and transformational leader, assisted in this commitment to change by improving the teachers' self-concepts as they slowly changed. The collaborative and receptive environment of the staff development fostered acceptance and stimulation of ideas.^ Given the collaborative nature of the change process, qualitative research methods were used in the investigation. The research process was based on Stufflebeam's Context, Input, Process and Product (CIPP) Evaluation Model (Madaus, Scriven & Stufflebeam, 1983). This allowed for all three factors of the staff development model to be evaluated. The case studies and focus group were effective in discerning any actual change in practices or beliefs.^ The findings of the qualitative evaluation, consisting of a baseline survey, case studies, questionnaire and modified focus group interviews, concluded that all of the teachers were strongly influenced by the intervention model which was the subject of this study. From this evaluation, three distinct indicators were looked at to determine if any change in the teachers' practices and beliefs emerged: (1) change in practice and belief, (2) reflective feedback and (3) collaborative reflection. These indicators were common throughout the teacher responses thus substantiating the infusion of the Facilitator-Collaborative-Reflective Model at the school level for effective staff development. ^

Directionality based preventive link maintenance scheme for mobile ad hoc networks

The purpose of this study was to design a preventive scheme using directional antennas to improve the performance of mobile ad hoc networks. In this dissertation, a novel Directionality based Preventive Link Maintenance (DPLM) Scheme is proposed to characterize the performance gain [JaY06a, JaY06b, JCY06] by extending the life of link. In order to maintain the link and take preventive action, signal strength of data packets is measured. Moreover, location information or angle of arrival information is collected during communication and saved in the table. When measured signal strength is below orientation threshold , an orientation warning is generated towards the previous hop node. Once orientation warning is received by previous hop (adjacent) node, it verifies the correctness of orientation warning with few hello pings and initiates high quality directional link (a link above the threshold) and immediately switches to it, avoiding a link break altogether. The location information is utilized to create a directional link by orienting neighboring nodes antennas towards each other. We call this operation an orientation handoff, which is similar to soft-handoff in cellular networks. ^ Signal strength is the indicating factor, which represents the health of the link and helps to predict the link failure. In other words, link breakage happens due to node movement and subsequently reducing signal strength of receiving packets. DPLM scheme helps ad hoc networks to avoid or postpone costly operation of route rediscovery in on-demand routing protocols by taking above-mentioned preventive action. ^ This dissertation advocates close but simple collaboration between the routing, medium access control and physical layers. In order to extend the link, the Dynamic Source Routing (DSR) and IEEE 802.11 MAC protocols were modified to use the ability of directional antennas to transmit over longer distance. A directional antenna module is implemented in OPNET simulator with two separate modes of operations: omnidirectional and directional. The antenna module has been incorporated in wireless node model and simulations are performed to characterize the performance improvement of mobile ad hoc networks. Extensive simulations have shown that without affecting the behavior of the routing protocol noticeably, aggregate throughput, packet delivery ratio, end-to-end delay (latency), routing overhead, number of data packets dropped, and number of path breaks are improved considerably. We have done the analysis of the results in different scenarios to evaluate that the use of directional antennas with proposed DPLM scheme has been found promising to improve the performance of mobile ad hoc networks. ^