Thomas Heistracher

The relationship between secondary flows and particle deposition patterns in airway bifurcations

The relationship between localized fluid dynamics and localized particle deposition patterns within bronchial airway bifurcations upon inspiration and expiration was analyzed for different bifurcation geometries, flow conditions, and particle sizes. For the simulation of three-dimensional airflow patterns in airway bifurcation models, the Navier-Stokes and continuity equations were solved numerically by the finite volume Computational Fluid Dynamics (CFD) program package FIRE. Spatial particle deposition patterns were determined by the intersection of randomly selected particle trajectories with the surrounding wall surfaces. While three-dimensional flow patterns were characterized by their corresponding two-dimensional secondary flow fields, three-dimensional deposition patterns were represented by their related two-dimensional deposition density plots. Two particle sizes were selected to explore the relationship between secondary flows and localized particle deposition patterns: 0.01 w m, to illustrate the effects of Brownian motion, and 10 w m, to display the effects of impaction and sedimentation. Changes in bifurcation geometry (shape of bifurcation zone, branching angle) and flow conditions (flow rate, inlet flow profile, direction of flow) lead to variations in resulting secondary flow patterns, which were reflected by corresponding differences in related particle deposition patterns. In conclusion, a distinct relationship could be observed between secondary flow patterns and deposition density plots, demonstrating that particle deposition patterns in airway bifurcations are not only determined by physical forces acting upon individual particles, but also by convective transport processes of the carrier fluid.

Simulation of a Self-Optimising Digital Ecosystem

Small and medium enterprises (SMEs) most often lack resources for custom-made software solutions that support best their core businesses. In this paper a simulation framework for self-optimising SME networks, namely Evolutionary Environment Simulator (EvESimulator), is introduced. The Evolutionary Environment, which the framework bases on, is an infrastructural component for distributed and decentralised service creation and service improvement based on mechanisms that are operating similarly in the living environment. This paper concentrates on the simulation of these mechanisms for SME networks. Built upon the widely-used simulation framework Repast, the cooperation behaviour of companies is investigated that use self-optimizing software services and distribute related information amongst them. The simulator is capable of importing real-world data from real businesses thereby enabling conceptual studies and hypothesis testing. It is applied in the context of three utilisation scenarios that investigate critical mass for sustainability, clustering in general, and usage-based clustering. The first results of the EvESimulator reveal a dynamic creation of a growing network of businesses that is clearly outperforming centralized topologies in the long run.

Model-transformation-based Software Generation utilizing Natural language notations

Adaptive software generation based on natural language notations is a key challenge in software industries. In the present work, the ability of stakeholders to formulate requirements that can directly be used in software production and software generation bases on a natural-language-based formal notation called Semantics for Business Vocabularies and Business Rules (SBVR), a recent OMG standard. SBVR-based model-to-model transformations are utilized to generate prototypical user interfacing code to demonstrate that non-IT business stakeholders can create framework-based software out of the box.

The significance of particle deposition patterns in bronchial airway bifurcations for extrapolation modeling

ABSTRACT The validity of extrapolating rat deposition data to human inhalation conditions depends on the degree of similarity (or difference) of their particle deposition patterns. Statistical analyses of human and rat tracheobronchial morphometry data have revealed distinct asymmetric features of their airway branching patterns, particularly for the monopodial branching structure of the rat lung. Our predictions of particle deposition patterns within asymmetric bronchial bifurcations in human and rat lungs are based on a numerical model for the calculation of airflow and aerosol particle trajectories in three-dimensional asymmetric bifurcation models: (i) the Navier-Stokes equations for the air velocity field are solved by a finite difference volume method, and (ii) trajectories of aerosol particles entrained in the airstream are simulated by Monte Carlo techniques. In the present paper, the effects of interspecies differences in particle deposition patterns are explored for two typical bifurcation geome...

Multi-Agent simulation framework for interdisciplinary research in digital ecosystems

The conceptualization and ongoing implementation of a network and service infrastructure for SMEs that bases on biologically inspired similes for service mediation needs thorough simulation and emulation capabilities that accompany that development. Digital Ecosystems (DE) are demand-driven self-organising agent environments exhibiting complex behaviour during utilisation and growth. To optimise this infrastructure, the capability of modelling of central DE mechanisms is a key success factor. In this paper the fully distributed Evolutionary Environment Simulator (EvESim) is discussed that enriches the DE infrastructure by simulation and emulation capabilities for the benefit of interdisciplinary research.

Bridging SCADA systems and GI systems

Supervisory Control and Data Acquisition (SCADA) systems are omnipresent in production operation worldwide. Failure detection within these systems remains a challenging task as the level of granularity in terms of location-based identification is low. The systems are able to identify and display failing components, but the situation becomes even more severe in case one of the failing components is not an electronic component but a structural component with a spatial extent such as a pipeline system. In consequence, the process of detection and repair of such components remains a time-consuming and cost-intensive task. To provide a generic solution for this kind of issues, the authors present a conceptualization and a software adapter bridging a SCADA system and a Geographic Information System (GIS). The authors employ international standards from both domains to enable an information exchange between these systems. The resulting autonomous software adapter and the corresponding prototypical implementation thus extends SCADA systems with GIS capabilities.

Collaborative Software Engineering with a Digital Ecosystem

Adaptation to changing requirements is one of the predominant challenges in distributed development. Software projects exceeding certain scales cannot be addressed by small-sized companies because of the incapability of meeting the financial guarantees and also because of staffing problems. In spite of their advantage of being more flexible, small companies when teaming up are usually overextended due to the overhead of communication and synchronization costs. A need emerges here for an infrastructure endorsing decomposability of software specifications and semi-automatic re-composition of the implemented components to satisfy the original requirements. This infrastructure facilitates a more efficient risk management due to the more finely grained specification. Such an infrastructure is presented here as a result of an ongoing research and implementation activity including real-world testing spanning several European countries and regions

Geographic Information Science as a common cause for interdisciplinary research

Geographic Information Science (GIScience) seeks to understand the nature of geographic phenomena and geo-spatial information. It provides theoretical foundations for Geographic Information Systems (GIS) and the rationale for research and development in GIS and their applications. In this article, we analyse the role of GIScience as a common denominator among and between various disciplines, acting as a facilitator for interdisciplinary research. Starting from the development of a coordinated and structured doctoral programme,ten senior university faculty members from different disciplines examine the commonalities of spatial (Because of limited space we focus in this paper on the spatial domain and will only briefly reflect the spatio-temporal complexity) concepts in their respective fields in three interdisciplinary research clusters. Since the educational rationale was published recently, we focus on the role of GIScience in building an interdisciplinary and inter-departmental research alliance and conclude that the university-wide visibility has increased and opens new changes for another ‘spatial turn’.

ENDORSE: a legal technical framework for privacy preserving data management

The ENDORSE project is concerned with providing assurances for data protection for both data controllers and data subjects. The project will define a rules based language called PRDL (Privacy Rules Definition Language) which can be used to express legislative requirements, organizational privacy policy as well as user consent. ENDORSE will provide a rules engine to ensure that privacy policies expressed in this language are compliant with legislative requirements for the applicable jurisdictions. In addition a set of technology adapters will be developed which will provide transformations from PRDL to target access control and policy configuration instances, which in turn can be used by organizations to ensure that internal data handling practices are in turn compliant. In parallel to this effort a certification methodology will be developed to provide a means of generating a privacy seals. This paper describes an overview of the project, the motivation behind the initiative, its aims and objectives as well as an introduction to the approach taken and technologies foreseen to achieves these aims. The paper also provides a discussion of how the results of the project can be applied in different scenarios.

A distributed agent-based approach for interdisciplinary collaboration

The unpredicted growth and high user acceptance of social networks motivates the need for powerful and flexible modeling tools that can support analysis and further improvement of these platforms. In this paper we introduce an agent-based distributed modeling framework that is capable of simultaneously simulating and emulating user behaviour in social networks. This framework is independent of the underlying technology and can thus be utilized to study dynamic behaviour in a variety of settings. It constitutes a platform for interdisciplinary collaboration based on its technological conception, which is outlined in this paper together with a first proof-of-concept trial in context with a large social network in Southern America.