Integrating legacy mainframe systems: architectural issues and solutions

For more than 30 years, mainframe computers have been the backbone of computing systems throughout the world. Even today it is estimated that some 80% of the worlds' data is held on such machines. However, new business requirements and pressure from evolving technologies, such as the Internet is pushing these existing systems to their limits and they are reaching breaking point. The Banking and Financial Sectors in particular have been relying on mainframes for the longest time to do their business and as a result it is they that feel these pressures the most. In recent years there have been various solutions for enabling a re-engineering of these legacy systems. It quickly became clear that to completely rewrite them was not possible so various integration strategies emerged. Out of these new integration strategies, the CORBA standard by the Object Management Group emerged as the strongest, providing a standards based solution that enabled the mainframe applications become a peer in a distributed computing environment. However, the requirements did not stop there. The mainframe systems were reliable, secure, scalable and fast, so any integration strategy had to ensure that the new distributed systems did not lose any of these benefits. Various patterns or general solutions to the problem of meeting these requirements have arisen and this research looks at applying some of these patterns to mainframe based CORBA applications. The purpose of this research is to examine some of the issues involved with making mainframebased legacy applications inter-operate with newer Object Oriented Technologies

A Pattern-Based Approach to Scaffold the IT Infrastructure Design Process

Context. The design of Information Technology (IT) infrastructures is a challenging task since it implies proficiency in several areas that are rarely mastered by a single person, thus raising communication problems among those in charge of conceiving, deploying, operating and maintaining/managing them. Most IT infrastructure designs are based on proprietary models, known as blueprints or product-oriented architectures, defined by vendors to facilitate the configuration of a particular solution, based upon their services and products portfolio. Existing blueprints can be facilitators in the design of solutions for a particular vendor or technology. However, since organizations may have infrastructure components from multiple vendors, the use of blueprints aligned with commercial product(s) may cause integration problems among these components and can lead to vendor lock-in. Additionally, these blueprints have a short lifecycle, due to their association with product version(s) or a specific technology, which hampers their usage as a tool for the reuse of IT infrastructure knowledge. Objectives. The objectives of this dissertation are (i) to mitigate the inability to reuse knowledge in terms of best practices in the design of IT infrastructures and, (ii) to simplify the usage of this knowledge, making the IT infrastructure designs simpler, quicker and better documented, while facilitating the integration of components from different vendors and minimizing the communication problems between teams. Method. We conducted an online survey and performed a systematic literature review to support the state of the art and to provide evidence that this research was relevant and had not been conducted before. A model-driven approach was also used for the formalization and empirical validation of well-formedness rules to enhance the overall process of designing IT infrastructures. To simplify and support the design process, a modeling tool, including its abstract and concrete syntaxes was also extended to include the main contributions of this dissertation. Results. We obtained 123 responses to the online survey. Their majority were from people with more than 15 years experience with IT infrastructures. The respondents confirmed our claims regarding the lack of formality and documentation problems on knowledge transfer and only 19% considered that their current practices to represent IT Infrastructures are efficient. A language for modeling IT Infrastructures including an abstract and concrete syntax is proposed to address the problem of informality in their design. A catalog of IT Infrastructure patterns is also proposed to allow expressing best practices in their design. The modeling tool was also evaluated and according to 84% of the respondents, this approach decreases the effort associated with IT infrastructure design and 89% considered that the use of a repository with infrastructure patterns, will help to improve the overall quality of IT infrastructures representations. A controlled experiment was also performed to assess the effectiveness of both the proposed language and the pattern-based IT infrastructure design process supported by the tool. Conclusion. With this work, we contribute to improve the current state of the art in the design of IT infrastructures replacing the ad-hoc methods with more formal ones to address the problems of ambiguity, traceability and documentation, among others, that characterize most of IT infrastructure representations. Categories and Subject Descriptors:C.0 [Computer Systems Organization]: System architecture; D.2.10 [Software Engineering]: Design-Methodologies; D.2.11 [Software Engineering]: Software Architectures-Patterns

Privacy-preserving framework for context-aware mobile applications

In recent years, the pervasiveness of mobile devices, especially mobile phones and personal digital assistants (PDAs), has increased rapidly. At the same time, wireless communication networks have improved considerably and the usage of mobile devices to access the internet is, with decreasing costs, possible almost everywhere and at any time in industrialized countries. However, the usage of mobile technology and mobile applications to support business processes, trans- actions, and personal tasks is still low compared to their potential. The improved capabilities resulted in the introduction of many applications for mobile devices by network operators and software vendors. These services were meant to increase the average revenue per user (ARPU) on top of the voice call income. But many of these services have failed and none of them has led to an improved usage of mobile services today, besides e-mail. A new kind of application, the context-aware application, exploits the ubiquity of the mobile devices in order to fit the personal need or task the user is about to execute satisfactorily. Context-aware systems try to improve the communication with the user by adding information about the current context to the explicit user input and by adapting the output to the current setting of the user. While those applications are seen as important steps to a widespread usage, there are strong factors inhibiting their development and adoption. First of all, the lack of common frameworks handling context data and improv- ing software development increases the cost to build context-aware applications. Each application currently implements its own sensors and logic to handle its data. Furthermore, service providers need to offer tailored services for every con- text of the user. Since no single provider is able to be an expert for all kinds of applications and will not have the necessary number of developers, a common service which finds services of multiple providers for the current situation of the user is needed. All services need to utilize the context attributes which are locally determined by the user’s situation. Development costs are further boosted by the difficulty of developing applications for multiple devices with varying input/output (IO) capabilities like speech output, small and big screens, full qwerty-keyboards, touchscreens, or numeric keypads. From the user’s perspective, privacy also endangers the adoption of mobile services. Context information may include very private data and expose the user’s preferences and habits. While the user may trust a single, well-known, provider to secure the private data and to respect the user’s privacy concerns, the problem increases with more and more smaller service providers

Modellierung und Generierung von Benutzeroberflächen für interaktive Softwaresysteme unter der Nutzung von Mustern

Die Dissertation umfasst den Entwurf einer Entwicklungsumgebung für Benutzeroberflächen, der modell- und musterbasierte UI-Entwicklung zu einem integrierten Entwicklungs- und Generierungsansatz kombiniert. Die Grundlagen der modell- und musterbasierten Entwicklung werden dargestellt und existierende Implementierungen analysiert. Die Ergebnisse der Untersuchungen fließen in den Entwurf der kombinierten Entwicklungsumgebung, der detailliert beschrieben wird, ein. Die Arbeit beinhaltet eine Fallstudie, die die praktische Bedeutung der theoretischen Ausführungen verdeutlicht