Dirk Draheim

Realistic load testing of Web applications

We present a new approach for performing load testing of Web applications by simulating realistic user behaviour with stochastic form-oriented analysis models. Realism in the simulation of user behaviour is necessary in order to achieve valid testing results. In contrast to many other user models, Web site navigation and time delay are modelled stochastically. The models can be constructed from sample data and can take into account effects of session history on user behaviour and the existence of different categories of users. The approach is implemented in an existing architecture modelling and performance evaluation tool and is integrated with existing methods for forward and reverse engineering

Process-centric analytical processing of version control data

We introduce a novel approach to enabling analytical processing of project data. The approach exploits source code repositories for information about project evolution. Furthermore we propose a new perspective on analyzing version control data. It takes up a process-centric viewpoint, addresses related analysis problems like collaboration of programmers and proposes metrics for them. The research has yielded an implementation of the approach, which comprises visualizations that assist in examining the evolution of software process.

A source code independent reverse engineering tool for dynamic Web sites

This paper describes a tool for black box reverse engineering of Web applications that reconstructs analysis models based on the concepts of form-oriented analysis. Recovering such models is motivated by requirements engineering and load testing. In particular, the paper addresses the problem of screen classification and discusses its conceptual underpinnings.

A type system for reflective program generators

In this paper we describe a type system for a generative mechanism that generalizes the concept of generic types by combining it with a controlled form of reflection. This mechanism makes many code generation tasks possible for which generic types alone would be insufficient. The power of code generation features are carefully balanced with their safety, so that we are able to perform static type checks on generator code. This leads to a generalized notion of type safety for generators.

Cloud-Aided Software Engineering: Evolving Viable Software Systems Through a Web of Views

Cloud computing is currently generating tremendous excitement in the IT industry. However, most cloud initiatives to date have focused on the delivery of computing services to end users, rather than on improving the engineering and governance of software systems. The cloud has the potential to revolutionize the way software is developed and governed and to consign much of the artificial complexity involved in software engineering today to history. It not only holds the key to reducing the tensions between agile and “heavyweight” methods of developing software, it also addresses the problem of software license management and piracy – software in the cloud cannot be copied! The cloud also promises to unlock the potential of large, heterogeneous distributed development teams by supporting social interaction, group dynamics, and key project management principles in software engineering. In this chapter, we outline the motivation for a cloud-driven approach to software engineering which we refer to as Cloud-Aided Software Engineering (CASE 2.0) and introduce some key innovations needed to turn it into reality. We also identify some of the main challenges that still need to be addressed and some of the most promising strategies for overcoming them.

Modelling form-based interfaces with bipartite state machines

This article presents the concept of form storyboarding, a new modelling method for eliciting, specifying and communicating functional requirements of applications with form-based interfaces. We identify two-staged interaction as the abstract concept behind form-based interfaces. The method encompasses a visual language for the documents to be created and a set of proposals for the activities involved in that. The method fits to different and ubiquitous types of submit/response style interfaces, i.e. mainframe terminals as well as web-based interfaces. The method yields an abstract interface model based on bipartite state machines. The model is executable and can be used for automatic prototype generation. Form storyboarding is first and foremost a feature-driven approach. The whole form storyboard can be obtained by collecting single system features. Crucial for this approach is the fact that diagrams can be combined in an easy operation, by building the union of both diagrams and identifying nodes and edges with the same name.

The Service-Oriented Metaphor Deciphered

Received 1 November 2010; Revised 6 December 2010; Accepted 13 December 2010 In this article we review the metaphor of service-oriented architecture for enterprise computing. In typical definitions service-oriented architecture appears as a single message and a consistent roadmap for building flexible software system landscapes. But it is not. Different communities have elaborated different SOA (service-oriented architecture) concepts to address different problem areas, i.e., enterprise application integration, business-to-business, business process management, and software productizing. If software architects and software managers are aware of these strands of SOA when talking about SOA in their projects they can avoid misunderstandings and detours better. This article contributes a clarification of the different strands of SOA concepts and technologies and their mutual dependencies and identifies particular SOA concepts as instances of more general software engineering principles.

A Versioning Model for Enterprise Services

Software systems based on a service-oriented architecture (SOA) are partitioned into loosely coupled services. Services may be developed by different parties, deployed to different nodes and operated by different organizations. In an SOA services may evolve independently from one another, ideally without sacrificing interoperability. Supporting service evolution is still a topic of ongoing research. We present a versioning model for supporting the evolution of service-oriented architectures. We present suggestions for release management, evolution scenarios, and a versioning scheme for enterprise services. The presented approach has been developed for an SOA in the banking domain.

Integrated model-based software development, data access, and data migration

In this paper we describe a framework for robust system maintenance that addresses specific challenges of data-centric applications. We show that for data-centric applications, classical simultaneous roundtrip engineering approaches are not sufficient. Instead we propose an architecture that is an integrated model-based approach for software development, database access and data migration. We explain the canonical development process to exploit its features. We explain how the approach fits into the model-driven architecture vision. We report on experiences with the approach in the IMIS environmental mass database project.

Business Process Technology

Currently, we see a lot of tools and techniques for specifying and implementing business processes. The problem is that there are still gaps and tensions between the different disciplines needed to improve business process execution and improvement in enterprises. Business process modeling, workflow execution and application programming are examples of disciplines that are hosted by different communities and emerged separately from each other. In particular, at the system analysis level concepts are not yet fully elaborated. Therefore, practitioners are faced again and again with similar questions in concrete business process projects: which decomposition mechanism to use? Who to find the correct granularity for business process activities? Which implementing technology is the optimal one in a given situation? This book approaches a systematization of the field. The method of the book is explicitly not a comparative analysis of existing tools and techniques – albeit the review of existing tools is a most important source for the considerations in the book. Rather, the book tries to provide a landscape of rationales and concepts in business processes with a discussion of alternatives.