Marcel Karam

Unit-level test adequacy criteria for visual dataflow languages and a testing methodology

Visual dataflow languages (VDFLs), which include commercial and research systems, have had a substantial impact on end-user programming. Like any other programming languages, whether visual or textual, VDFLs often contain faults. A desire to provide programmers of these languages with some of the benefits of traditional testing methodologies has been the driving force behind our effort in this work. In this article we introduce, in the context of prograph, a testing methodology for VDFLs based on structural test adequacy criteria and coverage. This article also reports on the results of two empirical studies. The first study was conducted to obtain meaningful information about, in particular, the effectiveness of our all-Dus criteria in detecting a reasonable percentage of faults in VDFLs. The second study was conducted to evaluate, under the same criterion, the effectiveness of our methodology in assisting users to visually localize faults by reducing their search space. Both studies were conducted using a testing system that we have implemented in Prographs IDE.

New Scheduling Architecture for IEEE 802.16 Wireless Metropolitan Area Network

IEEE 802.16 standard defines the specifications for emerging WiMAX networks. It did not however define the scheduling algorithms that determine the uplink and downlink bandwidth allocation. This paper proposes a preemptive deficit fair priority queue (PDFPQ) scheduling architecture for QoS management for the IEEE 802.16 standard. The proposed scheduling architecture is an extension of the DFPQ scheduling technique found in the literature. It enhances the QoS requirements of real time polling service (rtPS) flow class, and improves its delay and throughput. Compared to DFPQ, preliminary results show that a significant rtPS delay reduction and throughput increase can be realized with our new scheduling technique.

PHAODV: Power aware heterogeneous routing protocol for MANETs

Abstract Devices in mobile ad hoc networks (MANETs) have limited power resources and may be equipped with different transmission technologies. These characteristics make MANET traditional routing protocols inconvenient in a heterogeneous environment. Hence, the need for designing routing protocols that support interoperability between heterogeneous nodes and efficiently uses the available resources. In this paper, we propose a power aware routing protocol for a MANET formed of heterogeneous nodes. The proposed approach takes into consideration the battery status of nodes when building the routing table; in addition, in case of the existence of multiple routes between two nodes, the route that consumes least power is selected and the nodes falling on this route will be added to the routing table. Also, the proposed approach ensures fair distribution of routing load among the nodes and avoids exhausting nodes that are falling on optimal routes across the network, thus providing better connectivity and extending the network lifetime. We implemented the protocol as an extension to JiST/SWANS network simulator, and compared its performance to other heterogeneous and power aware routing protocols found in the literature.

A product-line architecture for web service-based visual composition of web applications

A web service-based web application (WSbWA) is a collection of web services or reusable proven software parts that can be discovered and invoked using standard Internet protocols. The use of these web services in the development process of WSbWAs can help overcome many problems of software use, deployment and evolution. Although the cost-effective software engineering of WSbWAs is potentially a very rewarding area, not much work has been done to accomplish short time to market conditions by viewing and dealing with WSbWAs as software products that can be derived from a common infrastructure and assets with a captured specific abstraction in the domain. Both Product Line Engineering (PLE) and Agile Methods (AMs), albeit with different philosophies, are software engineering approaches that can significantly shorten the time to market and increase the quality of products. Using the PLE approach we built, at the domain engineering level, a WSbWA-specific lightweight product-line architecture and combined it, at the application engineering level, with an Agile Method that uses a domain-specific visual language with direct manipulation and extraction capabilities of web services to perform customization and calibration of a product or WSBWA for a specific customer. To assess the effectiveness of our approach we designed and implemented a tool that we used to investigate the return on investment of the activities related to PLE and AMs. Details of our proposed approach, the related tool developed, and the experimental study performed are presented in this article together with a discussion of planned directions of future work.

HAODV: a New Routing Protocol to Support Interoperability in Heterogeneous MANET

In todays MANET, nodes can be equipped with one or more wireless communications interfaces that support different wireless technologies such as WIFI IEEE 802.11 and Bluetooth. Each technology implements distinct hardware and logical specifications. Current AODV routing protocol becomes inefficient when used in a network formed of heterogeneous devices. Indeed AODV in its nature search the paths between homogeneous devices and ignore the ones between heterogeneous devices. In this paper, we propose a heterogeneous AODV protocol that interoperates between WIFI and Bluetooth technologies in a single MANET. The extended algorithm takes into consideration several factors when building the routes such as network stability, traffic, conversion rate; in addition to the shortest path.

An Abstract Workflow-Based Framework for Testing Composed Web Services

Testing web services impose many challenges to existing testing methods, techniques, and tools; especially those available to traditional applications. Composed web services increase these challenges by requiring additional validation and verification efforts. Structural-based testing approaches have been thoroughly researched for traditional applications; however, they have not yet been examined, as a methodology, for testing composed web services. In this work, we introduce a formal model for an abstract-based workflow framework that can be used to capture a composed web service under test. We then define a set of applicable structural-based testing criteria to the framework. Finally we outline a promising line of testing criteria that can be applied to this framework.

An Abstract Model for Testing MVC and Workflow Based Web Applications

In this paper, we examine the classes of faults found in web applications that use development frameworks based on the MVC design pattern and the workflow paradigm. Our findings reveal opportunities to adapt state-based and code-based testing methodologies to test these faults. To support our proposed testing methodology, we propose an abstract workflow graph model and show, using an example, how state-based testing as well as structural-based testing methodologies can be applied to test MVC and workflow-based web applications.

A Novel Power Aware Heterogeneous Routing Protocol for MANETs

Devices in mobile ad hoc networks (MANETs) have limited power resources and may be equipped with different transmission technologies. These characteristics make MANET traditional routing protocols inconvenient in a heterogeneous environment. In this paper, we propose a power aware routing protocol for a MANET formed of heterogeneous nodes. The proposed approach takes into consideration the battery status of nodes when building the routing table. It aims to avoid exhausting the nodes that are falling on optimal routes across the network, thus providing better connectivity and extending the network lifetime. We implemented the protocol as an extension to JiST/SWANS network simulator, and compared its performance to other heterogeneous and power aware routing protocols found in the literature.

DuoTracker: Tool Support for Software Defect Data Collection and Analysis

In today software industry defect tracking tools either help to improve an organizations software development process or an individuals software development process. No defect tracking tool currently exists that help both processes. In this paper we present DuoTracker, a tool that makes possible to track and analyze software defects for organizational and individual software process decision making. To accomplish this, DuoTracker has capabilities to classify defects in a manner that makes analysis at both organizational and individual software processes meaningful. The benefit of this approach is that software engineers are able to see how their personal software process improvement impacts their organization and vice versa. This paper shows why software engineers need to keep track of their program defects, how this is currently done, and how DuoTracker offers a new way of keeping track of software errors. Furthermore, DuoTracker is compared to other tracking tools that enable software developers to record program defects that occur during their individual software processes.

Visual management of workflows in web development frameworks

Web development frameworks (WDFs) that incorporate both Workflow paradigms and the Model View Controller (MVC) [8] are known as WMVC-WFDs. Such frameworks guide the developer in generating the flow of control between the various components. Despite the pressing need for a visual environment to help developers manage the overwhelming number workflows during development, we have not come across any work that addresses this legitimate concern. In this work we describe, in the context of Ruby on Rail (ROR), an abstract model for the visual generation and management of workflows in WMVC-based web application.