Glêdson Elias

Performance Issues of Ad Hoc Routing Protocols in a Network Scenario used for Videophone Applications

In ad hoc mobile networks, the user mobility level, the range of possible network scenarios, and the traffic load generated by their typical applications are key aspects that make challenging to select a given routing protocol. In such a context, this paper presents a simulation-based performance analysis of ad hoc routing protocols in a hybrid ad hoc network scenario, which is used by mobile users to estabilish videophone sessions. The average packet delivery rate, end-to-end delay and routing load are measured and evaluated by varying the routing protocols, network range, number of nodes and user mobility.

A recommendation framework for allocating global software teams in software product line projects

In order to improve software quality and reduce costs and deadlines, many companies are adopting Software Product Line approaches. As a consequence of globalization, another common practice is the adoption of Global Software Development approaches, which seek to find more qualified workforce and more attractive costs in companies distributed around the world. Taking into account the benefits of both approaches, the ramework proposed in this paper has the goal of aiding the management of global software teams involved in the implementation phase of an SPL project, providing recommendations on how to allocate the teams to the set of software components, which are initially specified in the SPL architecture and must be subsequently implemented.

X-ARM: an asset representation model for component repository systems

Nowadays, one of the most challenging tasks in component-based software development processes is to discover suitable reusable assets that fulfill the requirements of a particular software system under development. In such a context, this paper presents an XML-based asset representation model for describing all kinds of software assets that can be produced or reused within component-based software development processes. The proposed model is based on asset metadata that provides effective means for developing universal repository systems that can deal with discovery, retrieval and composition of software components.

A Layered Routing Architecture for Infrastructure Wireless Mesh Networks

Due to architectural similarities, routing protocols designed for ad hoc networks have been applied to wireless mesh networks (WMNs). However, such routing protocols do not scale well in WMNs, requiring considerable research efforts for enhancing them. In order to scale up WMNs, this paper introduces a three-layered routing architecture designed for infrastructure WMNs, which explores a hybrid routing approach to reduce signaling overhead, power consumption and delay. The main strengths and innovations of the proposed architecture are the separation of routing concerns in three independent layers and the differentiation of routing strategies for static and mobile nodes.

QoS Specification and Management in a Middleware for Distributed Multimedia Systems

Multimedia systems should deal with critical issues such as real-time requirements of audio and video. Such requirements can become more complex when applications are executed in different platforms including different technologies, such as Internet and interactive digital television systems. In such a context, this paper proposes a QoS management and specification model to support adaptation in middleware for distributed multimedia systems

Integrating Communication Paradigms in a Mobile Middleware Product Line

Several middleware solutions have been proposed for supporting development of networked mobile applications, which are often designed with different distribution requirements and for various application scenarios. In this sense, a middleware that offers only a single communication paradigm (e.g., publish/subscribe) cannot cope with the diversity of applications and its reuse becomes very limited. In this context, this paper goal is to propose a mobile middleware solution which offers a set of communication paradigms, ranging from the traditional synchronous model to different variations of the so-called asynchronous models. In order to optimize memory footprint, common features in distributed communication are shared among all communication paradigms. Additionally, by means of a product line-based design, features can be selected and thus the middleware can be customized to better fit in more constrained devices.

Simulation-Based Performance Evaluation of the MLSD Protocol for Infrastructure WMNs

An Infrastructure Wireless Mesh Network (IWMN) is a multi-hop network that consists of stationary mesh routers, strategically positioned to provide a distributed wireless infrastructure for stationary or mobile mesh clients over a mesh topology. In this paper, we evaluate a network topology discovery protocol, called MLSD, which has been specifically designed considering IWMNs features. MLSD adopts a proactive, reliable, incremental, controlled and event-based delivery strategy, which avoids periodic messages and coordinates how information is propagated for enhancing efficiency and reducing network resource consumption. The performance evaluation is conducted based on simulation results. Performance is evaluated with respect to the total number of signaling messages and the signaling overhead. By contrasting MLSD and OSLR, it is observed that MLSD has the potential to become a better choice than the current project IEEE 802.11s, which adopts the OLSR approach as a basis for disseminating link state updates.

A component-based configuration and management framework for open, distributed multimedia systems

Distributed multimedia systems should deal with a diversity of hardware devices and operating systems issues. In such a context, we present a component-based framework for configuration and management of resources of open, distributed multimedia systems. In order to provide a generic and reusable approach, the framework explores the concept of properties to establish configuration agreements among component requirements and platform features.

A Search Service for Software Components Based on a Semi-Structured Data Representation Model

In order to make reuse practices effective, developers must find required components easily. In such a direction, representation models based on semi-structured data have been adopted to facilitate the discovery of required components. Following such a trend, this paper presents the architecture, functionalities and implementation of a search service that adopts techniques for indexing semistructured data, making possible the discovery of software assets through regular path expression queries.

A Scalable Neighborhood Discovery Protocol for Infrastructure Wireless Mesh Networks

Infrastructure Wireless Mesh Networks (IWMNs) have emerged as a promising technology for dynamic selfconfigurable and self-healing networks that provide large coverage, connectivity and resilience based on routing capabilities supported by their constituting nodes. In order to scale up IWMNs, it is an interesting approach to split routing capabilities into a layered routing architecture, in which the base layer is defined by a neighborhood discovery protocol employed to detect the presence and status of neighbor nodes. In such a context, this paper presents SNDP, a scalable neighborhood discovery protocol that has been specifically designed for IWMNs. SNDP adopts a hybrid, collaborative signaling strategy, in which different types of nodes adopt distinct signaling approaches that work together to manage neighborhood concerns. By reducing signaling load, power consumption and neighborhood discovery time, SNDP has the potential to become a better choice than the current work-in progress proposed by the IETF MANET working group.