Bluetooth networks can be constructed as piconets or scatternets depending on the number of nodes in the network. Although piconet construction is a well-defined process specified in Bluetooth standards, scatternet formation policies and algorithms are not well specified. Among many solution proposals for this problem, only a few of them focus on efficient usage of bandwidth in the resulting scatternets. In this paper, we propose a distributed algorithm for the scatternet formation problem that dynamically constructs and maintains a scatternet based on estimated traffic flow rates between nodes. The algorithm is adaptive to changes and maintains a constructed scatternet for bandwidth-efficiency when nodes come and go or when traffic flow rates change. Based on simulations, the paper also presents the improvements in bandwidth-efficiency and reduction in energy consumption provided by the proposed algorithm.

Abstract-Cloud computing has emerged as a new computing paradigm that impacts several different research fields, including software testing. Testing cloud applications has its own peculiarities that demand for novel testing methods and tools. On the other hand, cloud computing also facilitates and provides opportunities for the development of more effective and scalable software testing techniques. This paper reports on a systematic survey of published results attained by the synergy of these two research fields. We provide an overview regarding main contributions, trends, gaps, opportunities, challenges and possible research directions. We provide a review of software testing over the cloud literature and categorize the body of work in the field.

The increasing size and complexity of software systems has led to an amplified number of potential failures and as such makes it harder to ensure software reliability. Since it is usually hard to prevent all the failures, fault tolerance techniques have become more important. An essential element of fault tolerance is the recovery from failures. Local recovery is an effective approach whereby only the erroneous parts of the system are recovered while the other parts remain available. For achieving local recovery, the architecture needs to be decomposed into separate units that can be recovered in isolation. Usually, there are many different alternative ways to decompose the system into recoverable units. It appears that each of these decomposition alternatives performs differently with respect to availability and performance metrics. We propose a systematic approach dedicated to optimizing the decomposition of software architecture for local recovery. The approach provides systematic guidelines to depict the design space of the possible decomposition alternatives, to reduce the design space with respect to domain and stakeholder constraints and to balance the feasible alternatives with respect to availability and performance. The approach is supported by an integrated set of tools and illustrated for the open-source MPlayer software.

An analysis of the existing approaches for representing architectural views reveals that they focus mainly on functional concerns and are limited when considering quality concerns. We introduce the recovery style for modeling the structure of the system related to the recovery concern. The recovery style is a specialization of the module viewtype in the Views&Beyond approach. It is used to communicate and analyze architectural design decisions and to support detailed design with respect to recovery. We illustrate the style for modeling the recovery views for the open-source software, MPlayer.

CTIT Ph.D. thesis series no. 09-135.