The emerging Grid is extending the scope of resources to mobile devices and sensors that are connected through loosely connected networks. Nowadays, the number of mobile device users is increasing dramatically and the mobile devices provide various capabilities such as location awareness that are not normally incorporated in fixed Grid resources. Nevertheless, mobile devices exhibit inferior characteristics such as poor performance, limited battery life, and unreliable communication, compared with fixed Grid resources. Especially, the intermittent disconnection from network owing to users’ movements adversely affects performance, and this characteristic makes it inefficient and troublesome to adopt the synchronous message delivery in mobile Grid. This paper presents a mobile Grid system architecture based on mobile agents that support the location management and the asynchronous message delivery in a multi-domain proxy environment. We propose a novel balanced scheduling algorithm that takes users’ mobility into account in scheduling. We analyzed users mobility patterns to quantitatively measure the resource availability, which is classified into three types: full availability, partial availability, and unavailability. We also propose an adaptive load-balancing technique by classifying mobile devices into nine groups depending on availability and by utilizing adaptability based on the multi-level feedback queue to handle the job type change. The experimental results show that our scheduling algorithm provides a superior performance in terms of execution times to the one without considering mobility and adaptive load-balancing.

System adaptivity is increasingly demanded in high-performance embedded systems, particularly in multimedia system-on-chip (SoC), owing to growing quality-of-service requirements. This paper presents a reactive control model that has been introduced in Gaspard, our framework dedicated to SoC hardware/software co-design. This model aims at expressing adaptivity as well as reconfigurability in systems performing data-intensive computations. It is generic enough to be used for description in the different parts of an embedded system, for example, specification of how different data-intensive algorithms can be chosen according to some computation modes at the functional level; and expression of how hardware components can be selected via the usage of a library of intellectual properties according to execution performances. The transformation of this model toward synchronous languages is also presented, in order to allow an automatic code generation usable for formal verification, based on techniques such as model checking and controller synthesis, as illustrated in the paper. This work, based on Model-Driven Engineering and the standard UML MARTE profile, has been implemented in Gaspard.

WiMAX was proposed as the new wireless network standard in recent years. In the wide cover area of WiMAX environment, there are many nodes and interference. In order to obtain the efficiency, the avoidance to the interference is important. In this paper, we propose a two-tier cluster-based route scheduling mechanism on WiMAX Mesh mode. It achieves both fairness and efficiency inside and outside the cluster. The simulation result shows that our mechanism provides great improvement in average delay time and throughput than other research.

The need for reputation assessment is particularly strong in peer-to-peer (P2P) systems because the peers’ personal site autonomy is amplified by the inherent technological decentralization of the environment. However, the decentralization notion makes the problem of designing a P2P-based reputation assessment substantially harder in P2P networks than in centralized settings. Existing reputation systems tackle the reputation assessment process in an ad hoc manner. There is no systematic and coherent way to derive measures and analyze the current reputation systems. In this paper, we propose a reputation assessment process and use it to classify the existing reputation systems. Simulation experiments are conducted and focused on the different methods in selecting the recommendation sources and collecting the recommendations. These two phases can contribute significantly to the overall performance owing to precision, recall, and communication cost.

Video streaming over mobile wireless networks is getting popular in recent years. High video quality relies on large bandwidth provisioning, however, it decreases the number of supported users in wireless networks. Thus, effective bandwidth utilization becomes a crucial issue in wireless network as the bandwidth resource in wireless environment is precious and limited. The NGN quality of service mechanisms should be designed to reduce the impact of traffic burstiness on buffer management. For this reason, we propose an active dropping mechanism to deal with the effective bandwidth utilization in this paper. We use scalable video coding extension of H.264/AVC standard to provide different video quality for users of different levels. In the proposed dropping mechanism, when the network loading exceeds the threshold, the dropping mechanism starts to drop data of the enhancement layers for users of low service level. The dropping probability alters according to the change in network loading. With the dropping mechanism, the base station increases the system capability and users are able to obtain better service quality when the system is under heavy loading. We also design several methods to adjust the threshold value dynamically. By using the proposed mechanism, better quality can be provided when the network is in congestion.

Agile software development (ASD) has emerged as a result of consolidated values proposed under the lightweight methods of software engineering. Despite bearing some criticisms, the initial deployment and results observed in the practice environment represents its increasing domination over the traditional software development practices. Any ASD method, in particular, requires knowledge-intensive practices and typically employs multi-disciplinary expert team working extended periods of time for weeks on a nearly continuous basis. A huge amount of tacit knowledge creation and exchange happens in the entire process over the project lifecycle, which attracts the attention of research in the domain of knowledge management (KM). In this paper, first, we have mapped the agile values and agile principles, and in its support, we have argued upon and the need for integrated KM infrastructure and proposed a KM model that can be employed within the organization. We have also developed a conceptual framework for knowledge sharing and learning for the individual practitioners for the sustainability of agile team. We attempt to create an organizational learning framework for knowledge creation and exchange among the involved entities in a collaborative practice environment.