Christian Kücherer

Adaptive Wavelet Video Filtering

In this paper we propose a flexible adaptive media streaming mechanism based on wavelet encoded video streams. By using a combination of sender rate adaptation and filtering inside the transmission path, an appropriate tradeoff between flexibility, efficiency and security can be achieved. The media adaptation mechanisms are one part of the MASA Quality-of-Service framework, which provides end-to-end QoS enhanced multimedia communication and includes local resource management. We provide examples for syntactial and semantical filter algorithms, show the interaction of media adaptation and QoS management and present experimental measurement results.

A Task-oriented Requirements Engineering Method for Personal Decision Support Systems - A Case Study.

[Context and motivation] Personal Decision Support Systems (PDSSs) are information systems which support executives in decision-making by a decisionand user-specific data presentation. PDSSs operate on current data with predefined queries and provide a rich user interface (UI). Thus, a Requirements Engineering (RE) method for PDSSs should support the elicitation and specification of detailed requirements for specific decisions. However, existing RE approaches for decision support systems typically focus on ad-hoc decisions in the area of data warehouses. [Question/problem] Task-oriented RE (TORE) emphasizes a comprehensive RE specification which covers stakeholders’ tasks, data, system functions, interactions, and UI. TORE allows an early UI prototyping which is crucial for PDSS. Therefore, we want to explore TORE’s suitability for PDSSs. [Principal ideas/results] According to the Design Science methodology, we assess TORE for its suitability of PDSS specification in a problem investigation. We propose decision-specific adjustments of TORE (DsTORE), which we evaluate in a case study. [Contribution] The contribution of this paper is threefold. First, the suitability of the task-oriented RE method TORE for the specification of a PDSS is investigated as problem investigation. Second, a decision-specific extension of TORE is proposed as the DsTORE-method in order to identify and specify details of decisions to be supported by a PDSS. DsTORE is evaluated in a case study. Third, experiences from the study and method design are presented.

Task-oriented Requirements Engineering for Personal Decision Support Systems.

[Context and motivation] In decision-making, executives are supported by Personal Decision Support Systems (PDSSs) which are information systems providing a decision- and user-specific data presentation. PDSSs operate on current data with predefined queries and provide a rich user interface (UI). Therefore, a Requirements Engineering (RE) method for PDSSs should support the elicitation and specification of detailed requirements for specific decisions. However, existing RE approaches for decision support systems typically focus on ad-hoc decisions in the area of data warehouses. [Question/problem] Task-oriented RE (TORE) emphasizes a comprehensive RE specification which covers stakeholders’ tasks, data, system functions, interactions, and UI. TORE allows for an early UI prototyping which is crucial for PDSS. Therefore, we explore TORE’s suitability for PDSSs. [Principal ideas/results] According to the Design Science methodology, we assess TORE for its suitability for PDSS specification in a problem investigation. We propose decision-specific adjustments of TORE (DsTORE), which we evaluate in a case study. [Contribution] This paper is an extended version of previously published work. The contribution of this paper is fourfold. First, the suitability of the task-oriented RE method TORE for the specification of a PDSS is investigated as problem investigation. Second, the decision-specific extension of TORE is proposed as the DsTORE-method. DsTORE allows identifying and specifying details of decisions to be supported by a PDSS, utilizing a number of artifacts. Third, strategic information management is used as the example task for the evaluation of DsTORE in a case study. All interview questions used in the design science cycle are given. Experiences from the study and the method design are presented. Fourth, the evaluation of the developed system prototype is presented along with the questionnaire we used, showing the utility and acceptance.