Tool Support for Model-Driven Development of Web Applications

This paper describes the engineering foundations of VisualWADE, a CASE tool to automate the production of Web applications. VisualWADE follows a model-driven approach focusing on requirements analysis, high level design, and rapid prototyping. In this way, an application evolves smoothly from the first prototype to the final product, and its maintenance is a natural consequence of development. The paper also discusses the lessons learned in the development of the tool and its application to several case studies in the industrial context.

Web Data Warehousing Convergence

This paper proposes a data warehouse integration technique that combines data and documents from different underlying documents and database design approaches. The well-defined and structured data such as Relational, Object- oriented and Object Relational data, semi-structured data such as XML, and unstructured data such as HTML documents are integrated into a Web data warehouse system. The user specified requirement and data sources are combined to assist with the definitions of the hierarchical structures, which serve specific requirements and represent a certain type of data semantics using object-oriented features including inheritance, aggregation, association and collection. A conceptual integrated data warehouse model is then specified based on a combination of user requirements and data source structure, which creates the need for a logical integrated data warehouse model. A case study is then developed into a prototype in a Web-based environment that enables the evaluation. The evaluation of the proposed integration Web data warehouse methodology includes the verification of correctness of the integrated data, and the overall benefits of utilizing this proposed integration technique.

Modeling Variant User Interfaces for Web-Based Software Product Lines

Software product line (SPL) is a software engineering paradigm for software development. A software product within a product line often has specific functionalities that are not common to all other products within the product line. Those specific functionalities are termed “variant features” in a product line. SPL paradigm involves the modeling of variant features. However, little work in SPL investigates and addresses the modeling of variant features specific to user interface (UI). Unified Modeling Language (UML) is the de facto modeling language for object-oriented software systems. It is known that UML needs better support in modeling UIs. Thus, much research developed UML extensions to improve UML support in modeling UIs. Yet little of this work is related to developing such extensions for modeling UIs for SPLs in which variant features specific to UI modeling must be addressed. This research develops a UML extension -Web User Interface Modeling Language (WUIML) to address these problems. WUIML defines elements for modeling variant features specific to user interfaces for Web-based SPLs. The model elements in WUIML extend from the metaclass and BasicActivity of the UML2.0 metamodel. WUIML integrates the modeling of variant features specific to user interfaces to UML. For example, in a Web-based patient registration software product line, member products targeting British users may use British date format in the user interface, while member products targeting United States users may use United States date format in the user interface. Thus, this is a variant feature for this product line. WUIML defines a model element, XOR, to represent such exclusive or conditions in a product line user interface model. WUIML would reduce SPL engineers’ efforts needed in UI development. To validate the WUIML research outcome, a case study was conducted. The results of this empirical study indicate that modeling UIs for Web-based SPLs using WUIML is more effective and efficient than using standard UML.

Open Source in Web-Based Applications

Business and recreational activities on the global communication infrastructure are increasingly based on the use of remote resources and services, and on the interaction between different, remotely located parties. In such a context, Single Sign-On technologies simplify the log-on process allowing automatic access to secondary domains through a unique log-on operation to the primary domain. In this paper, we evaluate different Single Sign-On implementations focusing on the central role of Open Source in the development of Web-based systems. We outline requirements for Single Sign-On systems and evaluate four existing Open Source implementations in terms of degree of fulfilment of those requirements. Finally we compare those Open Source systems with respect to some specific Open Source community patterns.

Engineering Wireless Mobile Applications

Conventional desktop software applications are usually designed, built, and tested on a platform similar to the one on which they will be deployed and run. Wireless mobile application development, on the other hand, is more challenging because applications are developed on one platform (like UNIX or Windows) and deployed on a totally different platform like a cellular phone. While wireless applications can be much smaller than conventional desktop applications, developers should think in the small in terms of the devices on which the applications will run and the environment in which they will operate instead of the amount of code to be written. This paper presents a systematic approach to engineering wireless application and offers practical guidelines for testing them. What is unique about this approach is that it takes into account the special features of the new medium (mobile devices and wireless networks), the operational environment, and the multiplicity of user backgrounds; all of which pose new challenges to wireless application development.

Experience Report

Organizations are beginning to apply data mining and knowledge discovery techniques to their corporate data sets, thereby enabling the identification of trends and the discovery of inductive knowledge. Many times, traditional transactional databases are not optimized for analytical processing and must be transformed. This article proposes the use of modular components to decrease the overall amount of human processing and intervention necessary for the transformation process. Our approach con- figures components to extract data-sets using a set of “extraction hints”. Our framework incorporates decentralized, generic components that are reusable across domains and databases. Finally, we detail an implementation of our component-based framework for an aviation data set.

High Performance Scheduling Mechanism for Mobile Computing Based on Self-Ranking Algorithm (SRA)

Due to the rapidly increasing of the mobile devices connected to the internet, a lot of researches are being conducted to maximize the benefit of such integration. The main objective of this paper is to enhance the performance of the scheduling mechanism of the mobile computing environment by distributing some of the responsibilities of the access point among the available attached mobile devices. To this aim we investigate a scheduling mechanism framework that comprises an algorithm provides the mobile device with the authority to evaluate itself as a resource. The proposed mechanism is based on the proposing of “self ranking algorithm (SRA)” which provides a lifetime opportunity to reach a proper solution. This mechanism depends on event-based programming approach to start its execution in a pervasive computing environment. Using such mechanism will simplify the scheduling process by grouping the mobile devices according to their self -ranking value and assign tasks to these groups. Moreover, it will maximize the benefit of the mobile devices incorporated with the already existing grid systems by using their computational power as a subordinate value to the overall power of the system. Furthermore, we evaluate the performance of the investigated algorithm extensively, to show how it overcomes the connection stability problem of the mobile devices. Experimental results emphasized that, the proposed SRA has a great impact in reducing the total error and link utilization compared with the traditional mechanism.

Multi-Modal Modeling, Analysis, and Validation of Open Source Software Development Processes

Understanding the context, structure, activities, and content of software development processes found in practice has been and remains a challenging problem. In the world of free/open source software development, discovering and understanding what processes are used in particular projects is important in determining how they are similar to or different from those advocated by the software engineering community. Prior studies have revealed that development processes in F/OSSD projects are different in a number of ways. In this paper, we describe how a variety of modeling perspectives and techniques are used to elicit, analyze, and validate software development processes found in F/OSSD projects, with examples drawn from studies of the software requirements process found in the NetBeans.org project.

Secure Online DNS Dynamic Updates

Domain Name System (DNS) is the system for the mapping between easily memorizable host names and their IP addresses. Due to its criticality, the Internet Engineering Task Force (IETF) has defined a DNS Security Extension (DNSSEC) to provide data-origin authentication. In this paper, we point out two drawbacks of the DNSSEC standard in its handling of DNS dynamic updates: 1) the on-line storage of a zone security key, creating a single point of attack for both inside and outside attackers, and 2) the violation of the role separation principle, which in the context of DNSSEC requires the separation of the roles of zone security managers from DNS name server administrators. To address these issues, we propose an alternative secure DNS architecture based on threshold cryptography. Unlike DNSSEC, this architecture adheres to the role separation principle without presenting any single point of attack. To show the feasibility of the proposed architecture, we developed a threshold cryptography toolkit based on the Java Cryptography Architecture (JCA) and built a proof-of-concept prototype with the toolkit. Our running results of the prototype on a representative platform show that the performance of our proposed architecture ranges from one to four times of DNSSEC’s performance. Thus, through small performance overhead, our proposed architecture could achieve very high level of security.

On the Logarithmic Backoff Algorithm for MAC Protocol in MANETs

In wireless communication environments, backoff is traditionally based on the IEEE binary exponential backoff (BEB). Using BEB results in a high delay in message transmission, collisions and ultimately wasting the limited available bandwidth. As each node has to obtain medium access before transmitting a message, in dense networks, the collision probability in the MAC layer becomes very high when a poor backoff algorithm is used. The Logarithmic algorithm proposes some improvements to the backoff algorithms that aim to efficiently use the channel and to reduce collisions. The algorithm under study is based on changing the incremental behavior of the backoff value. The Binary Exponential Backoff (BEB) is used by the Local Area Networks standards, IEEE 802.11, Medium Access Control (MAC). BEB uses a uniform random distribution to choose the backoff value; this often leads to reducing the effect of window size increment. This paper carries out a deeper study and analysis of the logarithmic backoff algorithm that uses logarithmic increment instead of exponential extension of window size to eliminate the degrading effect of random number distribution. Results from simulation experiments reveal that the algorithm subject to study achieves higher throughput and less packet loss when in a mobile ad hoc environment.