Wilhelm Hasselbring

Information system integration

Consequently, public security and defense organizations can see the real-time locations of various people, units, and equipment in their GIS system, thanks to Global Positioning System (GPS) technology, while getting updates from SAP ERP with details about the current status and capabilities of those units, also updated in real-time as needed using enterprise services. With this bundle, users can create, maintain, and edit the relationships of organizational units (referred to in enterprise SOA terms as ) in public security and defense organizations (such as, for instance, Functional Units brigades, companies, and platoons), deployed or otherwise. In addition, they can read, change, and update the attributes of positions, personnel, and materials within these units.

Kieker: a framework for application performance monitoring and dynamic software analysis

Kieker is an extensible framework for monitoring and analyzing the runtime behavior of concurrent or distributed software systems. It provides measurement probes for application performance monitoring and control-flow tracing. Analysis plugins extract and visualize architectural models, augmented by quantitative observations. Configurable readers and writers allow Kieker to be used for online and offline analysis. This paper reviews the Kieker framework focusing on its features, its provided extension points for custom components, as well the imposed monitoring overhead.

Search-based genetic optimization for deployment and reconfiguration of software in the cloud

Migrating existing enterprise software to cloud platforms involves the comparison of competing cloud deployment options (CDOs). A CDO comprises a combination of a specific cloud environment, deployment architecture, and runtime reconfiguration rules for dynamic resource scaling. Our simulator CDOSim can evaluate CDOs, e.g., regarding response times and costs. However, the design space to be searched for well-suited solutions is extremely huge. In this paper, we approach this optimization problem with the novel genetic algorithm CDOXplorer. It uses techniques of the search-based software engineering field and CDOSim to assess the fitness of CDOs. An experimental evaluation that employs, among others, the cloud environments Amazon EC2 and Microsoft Windows Azure, shows that CDOXplorer can find solutions that surpass those of other state-of-the-art techniques by up to 60%. Our experiment code and data and an implementation of CDOXplorer are available as open source software.

Strategic information management plans: the basis for systematic information management in hospitals

Information management in hospitals is a complex task. In order to reduce complexity, we distinguish strategic, tactical, and operational information management. This is essential, because each of these information management levels views hospital information systems from different perspectives, and therefore uses other methods and tools. Since all these management activities deal only in part with computers, but mainly with human beings and their social behavior, we define a hospital information system as a sociotechnical subsystem of a hospital. Without proper strategic planning it would be a matter of chance, if a hospital information system would fulfil the information strategies goals. In order to support strategic planning and to reduce efforts for creating strategic plans, we propose a practicable structure.

Xbase: implementing domain-specific languages for Java

Xtext is an open-source framework for implementing external, textual domain-specific languages (DSLs). So far, most DSLs implemented with Xtext and similar tools focus on structural aspects such as service specifications and entities. Because behavioral aspects are significantly more complicated to implement, they are often delegated to general-purpose programming languages. This approach introduces complex integration patterns and the DSLs high level of abstraction is compromised. We present Xbase as part of Xtext, an expression language that can be reused via language inheritance in any DSL implementation based on Xtext. Xbase expressions provide both control structures and program expressions in a uniform way. Xbase is statically typed and tightly integrated with the Java type system. Languages extending Xbase inherit the syntax of a Java-like expression language as well as language infrastructure components, including a parser, an unparser, a linker, a compiler and an interpreter. Furthermore, the framework provides integration into the Eclipse IDE including debug and refactoring support. The application of Xbase is presented by means of a domain model language which serves as a tutorial example and by the implementation of the programming language Xtend. Xtend is a functional and object-oriented general purpose language for the Java Virtual Machine (JVM). It is built on top of Xbase which is the reusable expression language that is the foundation of Xtend.

Ontology-based modelling of architectural styles

The conceptual modelling of software architectures is of central importance for the quality of a software system. A rich modelling language is required to integrate the different aspects of architecture modelling, such as architectural styles, structural and behavioural modelling, into a coherent framework. Architectural styles are often neglected in software architectures. We propose an ontological approach for architectural style modelling based on description logic as an abstract, meta-level modelling instrument. We introduce a framework for style definition and style combination. The application of the ontological framework in the form of an integration into existing architectural description notations is illustrated.

CDOSim: Simulating cloud deployment options for software migration support

The evaluation of competing cloud deployment options (CDOs) forms a major challenge when migrating software systems to cloud environments. For example, there exists a plethora of potential cloud provider candidates, components must be mapped to suitable virtual machine instances, and, to exploit elasticity, appropriate runtime adaptation strategies for specific usage profiles have to be defined. But analyzing potential CDOs manually is intractable, costly, and time-consuming due to the heterogeneity of the cloud environments and the overall combinatorial design space complexity. We present the simulation tool CDOSim that can simulate cost and performance properties of those CDOs. It builds upon and significantly extends the cloud simulator CloudSim and integrates into our cloud migration framework CloudMIG. Additionally, we created a cloud benchmark to augment CloudMIGs cloud environment models with provider-specific performance characteristics. Along with this simulation input, CDOSim utilizes reverse-engineered architectural models and can employ actual monitored workload. We report on extensive experiments incorporating Eucalyptus and Amazon EC2 which show that CDOSim can sufficiently accurate predict the cost and performance properties of CDOs.

Federated integration of replicated information within hospitals

A fundamental concern in hospital informa- tion systems is the integration of information across heterogeneous subsystems at the data level. Consistent data replication is a central problem to be solved in this domain. The specific requirements and problems for integration of information within hospitals are discussed and a software architecture which has been designed according to these requirements is presented. The pur- pose of this paper is to study the problems and solutions of propagation of information updates across heteroge- neous subsystems within hospitals. The general structure of the presented architecture is based on the reference architecture for federated database systems (Sheth and Larson 1990) and adapted to the speci®c demands on integration of replicated information within hospital information systems. This architecture is the basis for algorithms that restore the integrity of replicated infor- mation when changes occur. A prototype implementa- tion is discussed.

An ontology-based approach for modelling architectural styles

The conceptual modelling of software architectures is of central importance for the quality of a software system. A rich modelling language is required to integrate the different aspects of architecture modelling, such as architectural styles, structural and behavioural modelling, into a coherent framework. We propose an ontological approach for architectural style modelling based on description logic as an abstract, meta-level modelling instrument. Architectural styles are often neglected in software architectures. We introduce a framework for style definition and style combination. The link between quality requirements and conceptual modelling of architectural styles is investigated. The application of the ontological framework in the form of an integration into existing architectural description notations such as ACME and UML-based approaches, and also service ontologies is illustrated.

Live trace visualization for comprehending large software landscapes: The ExplorViz approach

The increasing code complexity in modern enterprise software systems exceeds the capabilities of most software engineers to understand the systems behavior by just looking at its program code. Large software landscapes, e.g., applications in a cloud infrastructure, further increase this complexity. A solution to these problems is visualizing the applications of the software landscape to ease program comprehension and to understand the respective communication. An established visualization concept is the 3D city metaphor. It utilizes the familiarity with navigating a city to improve program comprehension. Dynamic analysis, e.g., monitoring, can provide the required program traces of the communication. In this paper, we present our live visualization approach of monitoring traces for large software landscapes. It combines a landscape and a system level perspective. The landscape level perspective provides an overview of the software landscape utilizing the viewers familiarity with UML. The system level perspective provides a visualization utilizing the city metaphor for each software system.