Managing software evolution in embedded systems

Verhoef, C. [Promotor]Klusener, A.S. [Copromotor

The Political Ecology of Takeovers: Thoughts On Harmonizing the European Corporate Governance Environment

Economic policy debate in the United States during the 1980s focused on the dynamics of bidder and target tactics in hostile takeovers. Confronted with the largest transactions in business history, financial economists took advantage of developments in econometric techniques to conduct virtually real time studies of the impact on firm value of each new bidder tactic and target defense. For courts and lawyers, hostile takeovers subjected standard features of corporate law to the equivalent of a stress x-ray, revealing previously undetected doctrinal cracks. Congress held seemingly endless hearings on the subject, although managing to enact only relatively innocuous tax penalties on particular defensive tactics the public found especially offensive. State legislatures, closer to the political action, acted more substantively, if less wisely. Whether or not takeovers created new wealth they did result in its transfer, and at least one of the parties from whom wealth was transferred – target management – had remarkable influence in state legislatures. When labor also came actively to oppose hostile takeovers, the coalition was virtually unstoppable. The decade saw some thirty-four states pass more than sixty-five major laws restricting corporate takeovers, including states discouraging partial offers and front-end loaded offers. The 1980s have now closed transactionally as well as chronologically. The first quarter of 1991 marked the lowest level of merger and acquisition activity since the first quarter of 1980. The passing of this remarkable decade invites a broader perspective, which can be helpfully thought of as the political ecology of takeovers. An ecological perspective builds on the proposition that phenomena are embedded in interactive systems – a rich web of mutually dependent relationships. Thus, a seemingly independent event cannot be fully evaluated without understanding how it relates to the environmental forces to which it was a response and which, in turn, respond to it. What the narrow focus of the 1980s debate missed was an appreciation of the complex economic corporate governance and political environments in which hostile takeovers are embedded. Corporate acquisitions are a response to real conditions in the economic environment. The choice among acquisition techniques, most importantly between friendly and hostile transactions, depends both upon the economic motivation for the transaction and upon conditions in the corporate governance environment. Finally, conditions in the corporate governance environment are directly influenced by politics; both what is allowed and prohibited is defined, in the first instance, by legislation. My goal in this article is two-fold. I begin by sketching the political ecology of takeovers in the United States – the interaction of economics, corporate governance and politics that shaped the experience of the 1980s. I then make a tentative effort at applying the insights gained from an ecological perspective to the current endeavor to change dramatically the European corporate governance environment through the harmonization of takeover and company law in the European Community. Sheltered by the cloak of political naivete commonly allowed those attempting comparative analysis from a distance, I will argue that an ecological understanding of takeovers suggests a different approach than that reflected so far in the debate over the terms of harmonization. This approach is based on what I term the mutability principle

Consolidation of Customized Product Copies into Software Product Lines

In software development, project constraints lead to customer-specific variants by copying and adapting the product. During this process, modifications are scattered all over the code. Although this is flexible and efficient in the short term, a Software Product Line (SPL) offers better results in the long term, regarding cost reduction, time-to-market, and quality attributes. This book presents a novel approach named SPLevo, which consolidates customized product copies into an SPL

Improving Information Retrieval Bug Localisation Using Contextual Heuristics

Software developers working on unfamiliar systems are challenged to identify where and how high-level concepts are implemented in the source code prior to performing maintenance tasks. Bug localisation is a core program comprehension activity in software maintenance: given the observation of a bug, e.g. via a bug report, where is it located in the source code? Information retrieval (IR) approaches see the bug report as the query, and the source files as the documents to be retrieved, ranked by relevance. Current approaches rely on project history, in particular previously fixed bugs and versions of the source code. Existing IR techniques fall short of providing adequate solutions in finding all the source code files relevant for a bug. Without additional help, bug localisation can become a tedious, time- consuming and error-prone task. My research contributes a novel algorithm that, given a bug report and the application’s source files, uses a combination of lexical and structural information to suggest, in a ranked order, files that may have to be changed to resolve the reported bug without requiring past code and similar reports. I study eight applications for which I had access to the user guide, the source code, and some bug reports. I compare the relative importance and the occurrence of the domain concepts in the project artefacts and measure the effectiveness of using only concept key words to locate files relevant for a bug compared to using all the words of a bug report. Measuring my approach against six others, using their five metrics and eight projects, I position an effected file in the top-1, top-5 and top-10 ranks on average for 44%, 69% and 76% of the bug reports respectively. This is an improvement of 23%, 16% and 11% respectively over the best performing current state-of-the-art tool. Finally, I evaluate my algorithm with a range of industrial applications in user studies, and found that it is superior to simple string search, as often performed by developers. These results show the applicability of my approach to software projects without history and offers a simpler light-weight solution

Consolidation of Customized Product Copies into Software Product Lines

Copy-based customization is a widespread technique to serve individual customer needs with existing software solutions. To cope with long term disadvantages resulting from this practice, this dissertation developed an approach to support the consolidation of such copies into a Software Product Line with a future-compliant product base providing managed variability

Consolidation of Customized Product Copies into Software Product Lines

In software development, project constraints lead to customer-specific variants by copying and adapting the product. During this process, modifications are scattered all over the code. Although this is flexible and efficient in the short term, a Software Product Line (SPL) offers better results in the long term, regarding cost reduction, time-to-market, and quality attributes. This book presents a novel approach named SPLevo, which consolidates customized product copies into an SPL

Inverse software configuration management

Software systems are playing an increasingly important role in almost every aspect of today’s society such that they impact on our businesses, industry, leisure, health and safety. Many of these systems are extremely large and complex and depend upon the correct interaction of many hundreds or even thousands of heterogeneous components. Commensurate with this increased reliance on software is the need for high quality products that meet customer expectations, perform reliably and which can be cost-effectively and safely maintained. Techniques such as software configuration management have proved to be invaluable during the development process to ensure that this is the case. However, there are a very large number of legacy systems which were not developed under controlled conditions, but which still, need to be maintained due to the heavy investment incorporated within them. Such systems are characterised by extremely high program comprehension overheads and the probability that new errors will be introduced during the maintenance process often with serious consequences. To address the issues concerning maintenance of legacy systems this thesis has defined and developed a new process and associated maintenance model, Inverse Software Configuration Management (ISCM). This model centres on a layered approach to the program comprehension process through the definition of a number of software configuration abstractions. This information together with the set of rules for reclaiming the information is stored within an Extensible System Information Base (ESIB) via, die definition of a Programming-in-the- Environment (PITE) language, the Inverse Configuration Description Language (ICDL). In order to assist the application of the ISCM process across a wide range of software applications and system architectures, die PISCES (Proforma Identification Scheme for Configurations of Existing Systems) method has been developed as a series of defined procedures and guidelines. To underpin the method and to offer a user-friendly interface to the process a series of templates, the Proforma Increasing Complexity Series (PICS) has been developed. To enable the useful employment of these techniques on large-scale systems, the subject of automation has been addressed through the development of a flexible meta-CASE environment, the PISCES M4 (MultiMedia Maintenance Manager) system. Of particular interest within this environment is the provision of a multimedia user interface (MUI) to die maintenance process. As a means of evaluating the PISCES method and to provide feedback into die ISCM process a number of practical applications have been modelled. In summary, this research has considered a number of concepts some of which are innovative in themselves, others of which are used in an innovative manner. In combination these concepts may be considered to considerably advance the knowledge and understanding of die comprehension process during the maintenance of legacy software systems. A number of publications have already resulted from the research and several more are in preparation. Additionally a number of areas for further study have been identified some of which are already underway as funded research and development projects