A. van der Hoek

A highly-extensible, XML-based architecture description language

Software architecture research focuses on models of software architectures as specified in architecture description languages (ADLs). As research progresses in specific areas of software architectures, more and more architectural information is created. Ideally, this information can be stored in the model. An extensible modeling language is crucial to experimenting with and building tools for novel modeling constructs that arise from evolving research. Traditional ADLs typically support a small set of modeling constructs very well, but adapt to others poorly. XML provides an ideal platform upon which to develop an extensible modeling language for software architectures. Previous XML-based ADLs successfully leveraged XMLs large base of off-the-shelf tool support, but did not take advantage of its extensibility. To give software architecture researchers more freedom to explore new possibilities and modeling techniques, while maximizing reuse of tools and modeling constructs, we have developed xADL 2.0, a highly extensible XML-based ADL. xADL 2.0 supports run-time and design time modeling, architecture configuration management and model-based system instantiation. Additionally, xADL 2.0 has a set of extensible infrastructure tools that support the creation, manipulation, and sharing of xADL 2.0 documents.

Towards Testing Product Line Architectures

Abstract A product line architecture is a single specification capturing the overall architecture of a series of closely related products. Its structure consists of a set of mandatory elements and a set of variation points. Whereas mandatory elements are part of the architecture of every product in the product line architecture, variation points precisely define the dimensions along which the architectures of individual products differ from each other. The increased use of product line architectures in todays software development projects poses several challenges for existing testing techniques. In this paper we discuss those challenges and discuss what we believe are opportunities for addressing them.

Comprehensive Evaluation of an Educational Software Engineering Simulation Environment

Software engineering educational approaches are often evaluated only anecdotally, or in informal pilot studies. We describe a more comprehensive approach to evaluating a software engineering educational technique (SimSE, a graphical, interactive, customizable, game-based software engineering simulation environment). Our method for evaluating SimSE went above and beyond anecdotal experience and approached evaluation from a number of different angles through a family of studies designed to assess SimSEs effectiveness and guide its development. In this paper, we demonstrate the insights and lessons that can be gained when using such a multi-angled evaluation approach. Our hope is that, from this paper, educators will: (1) learn ideas about how to more comprehensively evaluate their own approaches, and (2) be provided with evidence about the educational effectiveness of SimSE.

An environment for managing evolving product line architectures

The use of product lines is recognized as beneficial in promoting and structuring both component and architecture reuse throughout an organization. While the business practices of using product lines are well-understood and representations for specifying and capturing the underlying architecture of a product line are coming of age, support environments for managing the evolution of product line architecture are still lacking. In this paper, we present Menage, an environment specifically designed to alleviate this problem. Key features of Menage are its support for: (1) specifying variation points in product line architecture as optional and/or variant elements; (2) tracking the evolution of product line architecture and its constituent elements through explicit versioning techniques; and (3) selecting one or more product architectures out of overall product line architecture by applying user-specified criteria. In this paper, we introduce the approach underlying Menage, discuss its detailed functionality, and demonstrate its use with product line architecture for entertainment systems.

Using service utilization metrics to assess the structure of product line architectures

Metrics have long been used to measure and evaluate software products and processes. Many metrics have been developed that have lead to different degrees of success. Software architecture is a discipline in which few metrics have been applied, a surprising fact given the critical role of software architecture in software development. Software product line architectures represent one area of software architecture in which we believe metrics can be of especially great use. The critical importance of the structure defined by a product line architecture requires that its properties be meaningfully assessed and that informed architectural decisions be made to guide its evolution. To begin addressing this issue, we have developed a class of closely related metrics that specifically target product line architectures. The metrics are based on the concept of service utilization and explicitly take into account the context in which individual architectural elements are placed. We define the metrics, illustrate their use, and evaluate their strengths and weaknesses through their application on three example product line architectures.

Using Architectural Models to Manage and Visualize Runtime Adaptation

The architectural runtime configuration management approach provides an accurate model of adaptive software system behavior over time. ARCM improves the visibility and understandability of runtime adaptive processes while allowing human input into the adaptation-control loop.

Design and Evaluation of an Educational Software Process Simulation Environment and Associated Model

Simulation is an educational tool that is commonly used to teach processes that are infeasible to practice in the real world. Software process education is a domain that has not yet taken full advantage of the benefits of simulation. To address this, we have developed SimSE, an educational, interactive, graphical environment for building and simulating software engineering processes in a game-like setting. We detail the design of SimSE, present an initial simulation model of a waterfall process that we developed, and describe an experiment that we conducted to evaluate the educational potential of SimSE and its initial model

A testbed for configuration management policy programming

Even though the number and variety of available configuration management systems has grown rapidly in the past few years, the need for new configuration management systems still remains. Driving this need are the emergence of situations requiring highly specialized solutions, the demand for management of artifacts other than traditional source code and the exploration of entirely new research questions in configuration management. Complicating the picture is the trend toward organizational structures that involve personnel working at physically separate sites. We have developed a testbed to support the rapid development of configuration management systems. The testbed separates configuration management repositories (i.e., the stores for versions of artifacts) from configuration management policies (i.e., the procedures, according to which the versions are manipulated) by providing a generic model of a distributed repository and an associated programmatic interface. Specific configuration management policies are programmed as unique extensions to the generic interface, while the underlying distributed repository is reused across different policies. The authors describe the repository model and its interface and present their experience in using a prototype of the testbed, called NUCM, to implement a variety of configuration management systems.

Palantir: coordinating distributed workspaces

Distributed software development suffers from limited collaboration capabilities, as developers are unable to easily coordinate their efforts across physical boundaries. Different fields, such as CSCW and groupware, have attempted to bridge this gap, but few of the approaches developed so far have been incorporated in current software development environments. Configuration management (CM) systems are vital to any software development process, support distributed development, and are in widespread use. Unfortunately, they have only limited support for distributed collaboration. We describe Palantir, a system that is aimed at bringing collaborative capabilities to distributed development. Palantir builds upon existing CM systems to introduce project awareness to the developer workspace. In particular, Palantir supports close collaboration among developers by visualizing concurrent changes and showing, in real time, the severity and impact of those changes on the developers workspace.

A Comprehensive Evaluation of Workspace Awareness in Software Configuration Management Systems

Workspace awareness has emerged as a new coordination paradigm in configuration management, enabling early detection of potential conflicts by providing developers with information of relevant, parallel activities. The focus of our work is on detecting and mitigating direct and indirect conflicts by sharing information about ongoing code changes. In this paper, we discuss the results of user experiments designed as a broad and formative evaluation of workspace awareness, specifically focusing on whether users detect conflicts as they arise and act to mitigate potential problems. Our results confirm that workspace awareness promotes active self-coordination among users and can lead to an improved end-product in terms of the number of unresolved conflicts remaining in the code.