Henning Barthel

Visualization and Evolution of Software Architectures

Software systems are an integral component of our everyday life as we find them in tools and embedded in equipment all around us. In order to ensure smooth, predictable, and accurate operation of these systems, it is crucial to produce and maintain systems that are highly reliable. A well-designed and well-maintained architecture goes a long way in achieving this goal. However, due to the intangible and often complex nature of software architecture, this task can be quite complicated. The field of software architecture visualization aims to ease this task by providing tools and techniques to examine the hierarchy, relationship, evolution, and quality of architecture components. In this paper, we present a discourse on the state of the art of software architecture visualization techniques. Further, we highlight the importance of developing solutions tailored to meet the needs and requirements of the stakeholders involved in the analysis process.

Preattentive visualization of information relevance

When presenting complex, multidimensional data to users, emphasis of relevant information plays an important role. Especially when data is arranged according to several criteria, the simultaneous use of multiple visualization metaphors frequently results in information overload and unintuitive visualizations. In this paper, we present a comparison of preattentive visual features specifically for highlighting relevance of data extracted from electronic documents in an information-rich virtual environment. Several visual cues were evaluated with regard to their effectivity, comprehensibility and influence on other visualized features. At the same time we introduce two innovative data handling techniques to achieve practical applicability of our system: An intuitive way to reduce visual cluttering of information by filtering information based on its visual depth and a way to efficiently utilize visualizations of different dimensions - dimensional congruence.

Visualization of Software and Systems as Support Mechanism for Integrated Software Project Control

Many software development organizations still lack support for obtaining intellectual control over their software development processes and for determining the performance of their processes and the quality of the produced products. Systematic support for detecting and reacting to critical process and product states in order to achieve planned goals is usually missing. One means to institutionalize measurement on the basis of explicit models is the development and establishment of a so-called Software Project Control Center (SPCC) for systematic quality assurance and management support. An SPCC is comparable to a control room, which is a well known term in the mechanical production domain. One crucial task of an SPCC is the systematic visualization of measurement data in order to provide context-, purpose-, and role-oriented information for all stakeholders (e.g., project managers, quality assurance managers, developers) during the execution of a software development project. The article will present an overview of SPCC concepts, a concrete instantiation that supports goal-oriented data visualization, as well as examples and experiences from practical applications.

eCITY: A Tool to Track Software Structural Changes Using an Evolving City

One of the main challenges in the maintenance of large-scale software systems is to ascertain the underlying software structure and to analyze its evolution. In this paper we present a tool to assist software architects and developers in not only understanding the software structure of their system but more importantly to track the insertion, removal, or modification of components over time. The tool is based on the idea that the above-mentioned stakeholders should have an intuitive, efficient, and effective means to detect when, where, and what structural changes took place. The main components include an interactive visualization that provides an overview of these changes. The usefulness of this approach is highlighted through a summary of a user study we conducted.

Getting in touch with a cognitive character

We provide computer-animated characters with haptic interaction, allowing human users to interfere with cognitive characters. Our work presents an interface between control and animation of virtual characters (CONTACT) and HapTEK, a framework for haptic interaction of a human hand with virtual reality (VR). This way, human-computer interaction becomes truly bidirectional, i.e. an animated character directly provides feedback to a human user, and vice versa, introducing a new quality with respect to the behavior of both. Our system for the first time offers the opportunity for human and artificial intelligence to get in touch.

Visual analytics of software structure and metrics

In terms of software maintenance and comprehension, the fields of software engineering and software visualization have produced several methods and tools. However, they are typically separate tools in practice. In this paper, we present a novel methodology of combining software analysis and software visualization tools via an interactive visual workflow modeling approach. Standard software analysis tools are also limited in that they support only well-known metrics or are too complicated to use for generating custom software metrics. To address these shortcomings, our approach focuses on visual elements, their configurations, and interconnectivity rather than a data ontology and querying language. In order to test and validate our methodology, we developed a prototype tool called VIMETRIK (Visual Specification of Metrics). Our preliminary evaluation study illustrates the intuitiveness and ease-of-use of our approach with regard to understanding software measurement and analysis data.

eCITY+: A Tool to Analyze Software Architectural Relations through Interactive Visual Support

Current tools to analyze software architecture structure and its evolution tend to focus more towards exploring the architectural elements, their quality measures, and their evolution as compared to the information contained in the inter-dependencies of the system itself. In this tool demo paper, we present our eCITY+ tool that provides an interactive visualization aimed at assisting software engineers and architects to additionally comprehend the architectural ties between software components. Further, it shows how these relations evolve over time. To achieve these goals, eCITY+ represents architectural relationships as hierarchical edge bundles on top of an evolving software city metaphor and unravels the evolution of these relations through the use of animations. Additionally, we present a discussion on the challenges while implementing these ideas in the large.

Quality Improvement Through Visualization of Software and Systems

Many organizations still lack support for obtaining control over their system development processes and for determining the performance of their processes and the quality of the produced products. Systematic support for detecting and reacting to critical process and product states in order to achieve planned goals is often missing. As systems and software become bigger and more complex, classic approaches reach their limits, due to the difficulty of extracting relevant information from a large volume of measures. Here, suitable visualization and virtual reality solutions can offer a clear advantage by representing the relevant information in a more easily recognizable form. However, many resulting visualizations are still hard to understand, even for experts. This opens the door for researching modern, human-centered approaches that provide the user with visualization and interaction models for visually analyzing and understanding the underlying complex data. This chapter focuses on two main topics: system visualization and software visualization.

An Interactive Approach for Inspecting Software System Measurements

In recent times, visual analysis has become increasingly important, especially in the area of software measurement, as most of the data from software measurement is multivariate. In this regard, standard software analysis tools are limited by their lack of ability to process huge collections of multidimensional data sets; current tools are designed to either support only well-known metrics or are too complicated to use for generating custom software metrics. Furthermore, the analyst requires extensive knowledge of the underlying data schemas and the relevant querying language. To address these shortcomings, we propose an interactive visual approach that focuses on visual elements, their configurations, and interconnectivity rather than a data ontology and querying language. In order to test and validate our methodology, we developed a prototype tool called VIMETRIK (Visual Specification of Metrics). Our preliminary evaluation study illustrates the intuitiveness and ease-of-use of our approach to understand software measurement and analysis data.

eCITY: Evolutionary Software Architecture Visualization – An Evaluation

An essential component in the evolution and maintenance of large-scale software systems is to track the structure of a software system to explain how a system has evolved to its present state and to predict its future development. Current mainstream tools facilitating the structural evolution of software architecture by visualization are confined with easy to integrate visualization techniques such as node-link diagrams, while more applicable solutions have been proposed in academic research. To bridge this gap, we have incorporated additional views to a conventional tool that integrates an interactive evolving city layout and a combination of charts. However, due to a limited access to the stakeholders it was not possible to solicit them for a formal modeling process. Instead, an early prototype was developed and a controlled experiment was conducted to illustrate the vital role of such in-situ visualization techniques when aiming to understanding the evolution of software architecture.