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Group Communication (group + communication)

Distribution by Scientific Domains
Humanities and Social Sciences18%
Engineering18%

Selected Abstracts

Cooperative Strategy Training and Oral Interaction: Enhancing Small Group Communication in the Language Classroom

MODERN LANGUAGE JOURNAL, Issue 2 2006
DIANE NAUGHTON
This study focused on the effect of a cooperative strategy training program on the patterns of interaction that arose as small groups of students participated in an oral discussion task. The underlying assumption was that students could be taught to engage with each other and with the task in a way that would foster the creation and exploitation of learning opportunities. Intact classes were randomly assigned to the experimental or control condition, and triads from within each group were videotaped at the beginning and end of the experimental intervention. Data taken from the videotapes were analyzed in order to measure changes in overall participation, strategic participation, and the use of the individual strategies included in the program. The pretest showed that prior to strategy training, interaction patterns frequently did not reflect those interactions deemed important for language acquisition as identified within both traditional second language acquisition (SLA) and sociocultural research. The posttest revealed, however, that the strategy training program was largely successful in encouraging students to engage in these types of interactional sequences. [source]

Power aware scalable multicast routing protocol for MANETs

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2006
R. Manoharan
Abstract Multicasting is an effective way to provide group communication. In mobile ad hoc networks (MANETs), multicasting can support a wide variety of applications that are characterized by a close degree of collaboration. Since MANETs exhibit severe resource constraints such as battery power, limited bandwidth, dynamic network topology and lack of centralized administration, multicasting in MANETs become complex. The existing multicast routing protocols concentrate more on quality of service parameters like end-to-end delay, jitter, bandwidth and power. They do not stress on the scalability factor of the multicast. In this paper, we address the problem of multicast scalability and propose an efficient scalable multicast routing protocol called ,Power Aware Scalable Multicast Routing Protocol (PASMRP)' for MANETs. PASMRP uses the concept of class of service with three priority levels and local re-routing to provide scalability. The protocol also ensures fair utilization of the resources among the nodes through re-routing and hence the lifetime of the network is increased. The protocol has been simulated and the results show that PASMRP has better scalability and enhanced lifetime than the existing multicast routing protocols. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Scalable and fault-tolerant key agreement protocol for dynamic groups

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2006
A. Abdel-Hafez
With the widespread use of the Internet, the popularity of group communication-based applications has grown considerably. Since most communications over the Internet involve the traversal of insecure networks, basic security services are necessary for these collaborative applications. These security services can be facilitated if the authorized group members share a common secret. In such distributed applications, key agreement protocols are preferred to key distribution protocols. In the past two decades, there have been many proposals for key agreement protocols. Most of these protocols are not efficient and limit the size of the underlying group. In this paper, we consider the scalability problem in group key agreement protocols. We propose a novel framework based on extension of the Diffie,Hellman key exchange protocol. The efficiency of our protocol comes from the clustering of the group members, where the common session key is established collaboratively by all participants. We present the auxiliary protocols needed when the membership changes. We show that our protocol is superior in complexity in both communication and computation overheads required to generate the session key. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Using group communication to monitor web-based group learning

JOURNAL OF COMPUTER ASSISTED LEARNING, Issue 4 2003
G.D. Chen
Abstract, In a web group-learning environment, students must communicate with other group members on the Internet to accomplish group projects and share knowledge. Communication is likely to affect performance and so analysing the relationship between communicative relationships and group performance may help teachers to monitor groups effectively. Certain tasks are necessary to perform such an analysis , recording group communication, extracting communication relationships and determining the relationship between group communication and group performance. This study developed a method for determining relationships and rules for predicting performance to enable teachers to take act appropriately according to the predicted performance of the group. Four group performance indicators are considered , average grades within a group, project grade, frequency of resource-sharing and drop-out rate. Experimental results are presented, concerning the application of the methodology to a web class of 706 students, divided into 70 groups. The experimental results show that group communication patterns significantly affect group performance. [source]

The impact of group interaction on shared cognition: An analysis of small group communication

PROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2007
Miriam Matteson
First page of article [source]

Analytical modelling of users' behaviour and performance metrics in key distribution schemes

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2010
Massimo Tornatore
Access control for group communications must ensure that only legitimate users can access the authorised data streams. This could be done by distributing an encrypting key to each member of the group to be secured. To achieve a high level of security, the group key should be changed every time a user joins or leaves the group, so that a former group member has no access to current communications and a new member has no access to previous communications. Since group memberships could be very dynamic, the group key should be changed frequently. So far, different schemes for efficient key distribution have been proposed to limit the key-distribution overhead. In previous works, the performance comparison among these different schemes have been based on simulative experiments, where users join and leave secure groups according to a basic statistical model of users' behaviour. In this paper, we propose a new statistical model to account for the behaviour of users and compare it to the modelling approach so far adopted in the literature. Our new model is able to to lead the system to a steady state (allowing a superior statistical confidence of the results), as opposed to current models in which the system is permanently in a transient and diverging state. We also provide analytical formulations of the main performance metrics usually adopted to evaluate key distribution systems, such as rekey overheads and storage overheads. Then, we validate our simulative outcomes with results obtained by analytical formulations. Copyright © 2009 John Wiley & Sons, Ltd. [source]

An efficient dynamic group key agreement protocol for imbalanced wireless networks

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2010
Yun-Hsin Chuang
Owing to the popularity of wireless networks, the group key agreement (GKA) design is critical for providing secure group communications over an insecure wireless channel. In 2005, Nam et al. proposed a GKA protocol for imbalanced wireless networks in which an imbalanced wireless network consists of many mobile nodes with limited computing capability and a powerful node with less restriction. In 2007, Tseng showed that Nam et al.'s protocol is not a contributory GKA, while he also proposed a new GKA protocol. However, neither GKA protocol is concerned with dynamic member joining/leaving. This is an important functionality of GKA, especially for a wireless network environment. In this paper, we propose a dynamic group key agreement protocol for imbalanced wireless networks, and show that it requires less computation cost for dynamic member joining/leaving as compared to the previously proposed protocols. We also show that the proposed protocol is provably secure against passive attacks under the decision Diffie,Hellman problem and the hash function assumptions. Furthermore, by the pre-shared two-party key between a mobile node and the powerful node in the existing imbalanced wireless networks, we propose a generalized GKA protocol that requires only several hash functions. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Scalable and lightweight key distribution for secure group communications

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 3 2004
Fu-Yuan Lee
Securing group communications in dynamic and large-scale groups is more complex than securing one-to-one communications due to the inherent scalability issue of group key management. In particular, cost for key establishment and key renewing is usually relevant to the group size and subsequently becomes a performance bottleneck in achieving scalability. To address this problem, this paper proposes a new approach that features decoupling of group size and computation cost for group key management. By using a hierarchical key distribution architecture and load sharing, the load of key management can be shared by a cluster of third parties without revealing group messages to them. The proposed scheme provides better scalability because the cost for key management of each component is independent of the group size. Specifically, our scheme incurs constant computation and communication overheads for key renewing. In this paper, we present the detailed design of the proposed scheme and performance comparisons with other schemes. Briefly, our scheme provides better scalability than existing group key distribution approaches.,Copyright © 2004 John Wiley & Sons, Ltd. [source]