Open Access

Forschungsjahresbericht 2008 der Hochschule Konstanz Technik, Wirtschaft und Gestaltung

Für den deutschen bzw. europäischen Tourismus ist Indien seit Jahrzehnten eine Destination, die kulturtouristisch, aber auch zunehmend gesundheitstouristische interessant ist. Sonderformen wie spiritueller Tourismus, nachhaltiger Tourismus oder Tanztourismus (Bollywood-Dance) haben sich in Nischen etabliert oder beginnen diese zu verlassen. Indien selbst unternahm mit seiner Kampagne „Incredible India“ 2002 eine weltweit beachtete, selbstironische Initiative, sich als „unglaubliche“ Destination in den Auslandsmärkten zu positionieren. Demgegenüber steht eine Realität in Indien, die einerseits Massenarmut, Korruption, Sicherheitsprobleme, Bürokratie und mangelnde Infrastruktur ebenso vorhält wie eine beeindruckende Kultur- und Naturlandschaft, gut ausgebildete englischsprachige Menschen, ethnische Vielfalt sowie Mystik und Spiritualität. Indien definiert sich – auch touristisch – durch Extreme (vgl. Freyer & Thimm 2011: 261).

Im Rahmen dieser Masterarbeit wurde an einem Beispielgebäude (Wessenberg-Schule Konstanz) gezeigt, dass Maßnahmen an der Gebäudehülle von Gebäuden der 60er-Jahre trotz Denkmalstatus ein durchaus erhebliches Potential aufweisen, um Wärmeverluste zu begrenzen, und sich Denkmalcharakter und energetischer Modernisierungswunsch nicht zwangsläufig gegenseitig ausschließen. Hierbei wurden Thermografieaufnahmen angefertigt, Temperaturmessungen durchgeführt und U-Werte aller Bauteile der Gebäudehülle berechnet. Die Maßnahmen wurden auf Wärmebrücken und den Gesamtwärmedurchlass hin separat für jedes Bauteil bewertet. Für gezielte Sanierungsvorschläge und die Untersuchung ihrer Wirksamkeit wurde das Gebäude intensiv untersucht. Hierbei wurden Informationen aus Archiven (Stadtarchiv Konstanz, Kreisarchiv Konstanz und Südwestdeutsches Archiv für Architektur und Ingenieurbau) zusammengetragen, die ein breites Bild des Bauablaufs und -geschichte, der verwendeten Baustoffe und der Architektur geben. Da keine ausführliche Denkmalbegründung vorlag, wurde die Architektur und Gestaltung des Gebäudes separat betrachtet und bewertet.

Informiert über die Forschungsaktivitäten an der Hochschule Konstanz im Jahr 2016. Supplement to the German edition: Chapter "Experts" in English edition, Professors of the HTWG an their expertises and research areas

Schwerpunktthema: Vernetzung

This work investigates data compression algorithms for applications in non-volatile flash memories. The main goal of the data compression is to minimize the amount of user data such that the redundancy of the error correction coding can be increased and the reliability of the error correction can be improved. A compression algorithm is proposed that combines a modified move-to-front algorithm with Huffman coding. The proposed data compression algorithm has low complexity, but provides a compression gain comparable to the Lempel-Ziv-Welch algorithm.

Control of the armature motion of fast-switching solenoid valves is highly desired to reduce noise emission and wear of material. For feedback control, information of the current position and velocity of the armature are necessary. In mass production applications, however, position sensors are unavailable due to cost and fabrication reasons. Thus, position estimation by measuring merely electrical quantities is a key enabler for advanced control, and, hence, for efficient and robust operation of digital valves in advanced hydraulic applications. The work presented here addresses the problem of state estimation, i.e., position and velocity of the armature, by sole use of electrical measurements. The considered devices typically exhibit nonlinear and very fast dynamics, which makes observer design a challenging task. In view of the presence of parameter uncertainty and possible modeling inaccuracy, the robustness properties of sliding mode observation techniques are deployed here. The focus is on error convergence in the presence of several sources for modeling uncertainty and inaccuracy. Furthermore, the cyclic operation of switching solenoids is exploited to iteratively correct a critical parameter by taking into account the norm of the observation error of past switching cycles of the process. A thorough discussion on real-world experimental results highlights the usefulness of the proposed state observation approach.

Proceeding of the Conference on Mathematics and its Applications–2014, held from November 14–17, 2014, at Kuwait University, Safat, Kuwait.

A real matrix is called totally nonnegative if all of its minors are nonnegative. In this paper the extended Perron complement of a principal submatrix in a matrix A is investigated. In extension of known results it is shown that if A is irreducible and totally nonnegative and the principal submatrix consists of some specified consecutive rows then the extended Perron complement is totally nonnegative. Also inequalities between minors of the extended Perron complement and the Schur complement are presented.

Ausstellungskatalog Kunstverein Eislingen 10.9. - 9.10.2016 “It is truly hard to grasp: An impenetrable tangle of rods, tubes, and panels spreads out before us, opening up in a nearly endless expanse that leaves us reeling. Diagonals abruptly pull our gaze upward, where crooked huts teeter on lightweight rods. Neither the spatial expanse nor the abundance of details in Katrin Günther’s monumental drawings can be comprehended.“ Heinz Stahlhut, Kunstmuseum Luzern The new book by Katrin Günther provides an in-depth look into the fascinating work of the Berlin artist. Numerous color reproductions and details, supplemented by stimulating texts, offer an extensive overview of her drawings. Quelle: https://www.kerberverlag.com/de/katrin-gunther.html

The method of signal injection is investigated for position estimation of proportional solenoid valves. A simple observer is proposed to estimate a position-dependent parameter, i.e. the eddy current resistance, from which the position is calculated analytically. Therefore, the relationship of position and impedance in the case of sinusoidal excitation is accurately described by consideration of classical electrodynamics. The observer approach is compared with a standard identification method, and evaluated by practical experiments on an off-the-shelf proportional solenoid valve.

The aim of the paper is to present the simulation of the sweeping process based on a mathematical model that includes the drag force, the lift force, the sideway force, and the gravity. At the beginning, it is presented a short history of the street sweepers, some considerations about the sweeping process and the parameters of the sweeping process. Considering the developed model, in Matlab there is done some simulation for the trajectory of a spherical pebble. The obtained results are presented in graphical shape.

Stress is becoming an important topic in modern life. The influence of stress results in a higher rate of health disorders such as burnout, heart problems, obesity, asthma, diabetes, depressions and many others. Furthermore individual’s behavior and capabilities could be directly affected leading to altered cognition, inappropriate decision making and problem solving skills. In a dynamic and unpredictable environment, such as automotive, this can result in a higher risk for accidents. Different papers faced the estimation as well as prediction of drivers’ stress level during driving. Another important question is not only the stress level of the driver himself, but also the influence on and of a group of other drivers in the near area. This paper proposes a system, which determines a group of drivers in a near area as clusters and it derives the individual stress level. This information will be analyzed to generate a stress map, which represents a graphical view about road section with a higher stress influence. Aggregated data can be used to generate navigation routes with a lower stress influence to decrease stress influenced driving as well as improve road safety.

Recent years have seen the proposal of several different gradient-based optimization methods for training artificial neural networks. Traditional methods include steepest descent with momentum, newer methods are based on per-parameter learning rates and some approximate Newton-step updates. This work contains the result of several experiments comparing different optimization methods. The experiments were targeted at offline handwriting recognition using hierarchical subsampling networks with recurrent LSTM layers. We present an overview of the used optimization methods, the results that were achieved and a discussion of why the methods lead to different results.

Südstadt Tübingen is a successful military land redevelopment project, in which functional mix and urban diversity have been identified as main goals. In the whole development process, joint building venture has been utilized as important urban development instrument. On one hand, this instrument helps citizens development adaptive and affordable living space and let them find own identity to the new quarter; on the other hand, it is also important to cultivate urban diversity and suitable spatial feeling, mix relationship in living and working conditions, so that the quarters will have very flexible structure to accommodate diversified urban life styles.

Wie können archäologische Forschungsergebnisse einer breiten Öffentlichkeit möglichst eindrücklich und nachvollziehbar vermittelt werden? Am Beispiel der UNESCO-Welterbestätte Pfahlbausiedlung Hornstaad demonstrieren Studierende der Hochschule für Technik, Wirtschaft und Gestaltung Konstanz (HTWG) die Visualisierung komplexer wissenschaftlicher Inhalte mithilfe moderner Virtual- Reality-Brillen-Technologie (VR-Brillen). Eine dreidimensionale digitale Rekonstruktion der Pfahlbausiedlung und Simulation von Tages- und Jahresverlauf in Verbindung mit der realen Bewegung im Ausstellungsraum ermöglichen dem Betrachter das hautnahe Erleben des Alltags in einer neolithischen Siedlung. Das Ausstellungsprojekt „Das Gedächtnis des Sees“ wird im Rahmen der Großen Landesaustellung „4000 Jahre Pfahlbauten“ zu sehen sein.

This report contains two parts: The first part presents an overview on studies concerning the Danube, inland navigation or the impact of climate change on either of those. The second part gives a more detailed analysis of inland navigation on the Danube, partly based on studies presented in part one. Part two covers the current situation along the Danube by covering the topic of bottlenecks and other limitations for shipping along the Danube. Based on these informations, an estimation of the economic impacts of low water periods on inland navigation is made. As a last step, measures to reduce the impact of low water on inland navigations are presented. The report shows, that inland navigation still is an important transport mode, along the Danube as well as in other european regions. Especially in Romania, inland navigation still has a large share of more than 20% and rising in total transport. However, inland navigation depends strongly on good conditions of its infrastructure. These good conditions are limited mainly by two factors: one are the so called bottlenecks. Those are areas with sub-optimal shipping conditions e.g. due to solid rock formations in the river that lead to a reduced water depths. The other factor is the weather (and, on a longer time scale, the climate) which, mostly depending on precipitation and evaporation, can lead to low water levels seasonally. In addition to these two natural factors, laws which e.g. regulate the maximum number of barges allowed. Human build structures like locks limit the size of vessels as well as the speed they can travel with. These limiting factors are identified and located in the first chapter of part two of this report, before the water depth needed by several ship sizes as well as the cargo fleet available along the Danube are presented. One of the targets of this report is to estimate the economic impact of low water periods. All the factors named above as well as the freight prices charged for connections along the Danube are used to each this target in chapter II.4. To estimate the impact of low water periods on the freight prices, a method developed by Jonkeren et al. (2007) for the Rhine is transfered to the Danube. By transfering Jonkeren et al. (2007) method, regression equations for several transport connections along the Danube are identified that give a first estimate for the connection of freight prices and water levels. With the help of these regression equations, an estimation of the total expenses for transport via inland navigation for several years is possible. The yearly and seasonal variability is identified as well as the additional expenses due to water levels below 280cm. But additional expenses are not the only impact of changing water levels on inland navigation. Another is, that while the demand for transport stays at the same level, sometimes the water levels are not sufficient enough to use the full capacity of the fleet. Therefore, the (theoretical) amount of cargo that could not be transported due to low water levels is calculated as well and presented in chapter II.5. Finally, some measures to overcome some of the here named problems of inland navigation due to low water levels are presented. These are separated into two general approches: change the ship or change the river. Both methods have their advantages and disadvantages due to technical as well as regulatory and other factors. The list presented here however is incomplete and only gives a few ideas of how some problems can be overcome. In the end, an individual mix for the different regions along the river and sometimes for the individual companies must be found.

Digital bedruckte Oberflächen müssen strengen funktionalen und ästhetischen Anforderungen genügen. Diese Eigenschaften werden im Rahmen der Qualitätsprüfung kontrolliert. Hierbei wirken sich Oberflächendefekte oftmals erst dann aus, wenn diese auch vom Menschen wahrgenommen werden. Aufgrund der hohen Produktionsgeschwindigkeit kann eine solche Bewertung der Sichtbarkeit von Defekten bisher nur außerhalb des Produktionsflusses durch manuelle - subjektiv geprägte - Inspektion erfolgen. Ziel des Projektes ist (1) die Modellierung von Texturen in einer Form, die an das menschliche visuelle System angepasst ist und (2) die automatisierte Beurteilung der Wahrnehmung von Texturfehlern. Im Rahmen des Projekts wurde ein prototypisches System zur Inline-Erfassung von texturierten Oberflächen entwickelt. Auf Basis von realen Aufnahmen industriell produzierter Holzdekore wurde eine repräsentative Texturdatenbank erstellt. Gezeigt werden erste Resultate im Bereich der Defektdetektion auf Basis von statistischen Merkmalen. Diese Ergebnisse dienen als Grundlage für die spätere wahrnehmungsorientierte Bewertung. Letztlich sollen die im Rahmen des Projekts erlangten Ergebnisse in einen prototypischen Aufbau zur Inspektion von digital bedruckten Dekoren einfließen.

Die Etablierung eines Compliance-Management-Systems (CMS) stößt v. a. im Mittelstand immer wieder auf teils erheblichen (kosten- wie kulturbedingten) Widerstand. Der nachfolgende Beitrag erläutert Motive und Gründe zur Einrichtung eines CMS, welches eine systematische Sicherstellung der Einhaltung von geltenden Gesetzen sowie internen Vorgaben gewährleisten soll, um Unternehmen und deren Organe sowie Mitarbeiter vor rechtlichen Risiken zu schützen.

Even though immutability is a desirable property, especially in a multi-threaded environment, implementing immutable Java classes is surprisingly hard because of a lack of language support. We present a static analysis tool using abstract bytecode interpretation that checks Java classes for compliance with a set of rules that together constitute state-based immutability. Being realized as a Find Bugs plug in, the tool can easily be integrated into most IDEs and hence the software development process. Our evaluation on a large, real world codebase shows that the average run-time effort for a single class is in the range of a few milliseconds, with only a very few statistical spikes.

Creating cages that enclose a 3D-model of some sort is part of many preprocessing pipelines in computational geometry. Creating a cage of preferably lower resolution than the original model is of special interest when performing an operation on the original model might be to costly. The desired operation can be applied to the cage first and then transferred to the enclosed model. With this paper the authors present a short survey of recent and well known methods for cage computation. The authors would like to give the reader an insight in common methods and their differences.

In this paper we provide a performance analysis framework for wireless industrial networks by deriving a service curve and a bound on the delay violation probability. For this purpose we use the (min,×)stochastic network calculus as well as a recently presented recursive formula for an end-to-end delay bound of wireless heterogeneous networks. The derived results are mapped to WirelessHART networks used in process automation and were validated via simulations. In addition to WirelessHART, our results can be applied to any wireless network whose physical layer conforms the IEEE 802.15.4 standard, while its MAC protocol incorporates TDMA and channel hopping, like e.g. ISA100.11a or TSCH-based networks. The provided delay analysis is especially useful during the network design phase, offering further research potential towards optimal routing and power management in QoS-constrained wireless industrial networks.

Die Seewassernutzung weist ein beachtliches Potential zu Kühl- und Heizzwecken auf. Bereits seit längerem eingesetzte seewasserbetriebene Wärmepumpen in der Schweiz beweisen fortwährend ihre Praxistauglichkeit. In Deutschland wird diese Technik jedoch bislang kaum genutzt. Mit Hilfe eines interdisziplinären geowissenschaftlichen Ansatzes wird derzeit das bestehende Potential in Deutschland quantifiziert und dessen Nutzungshemmnisse identifiziert, um in einem weiteren Schritt Handlungsoptionen für einen verstärkten Einsatz dieser Technologie zu erarbeiten.

Cognitive radio (CR) is a key enabler of wireless in industrial applications especially for those with strict quality-of-service (QoS) requirements. The cornerstone of CR is spectrum occupancy prediction that enables agile and proactive spectrum access and efficient utilization of spectral resources. Hidden Markov Models (HMM) provide powerful and flexible tools for statistical spectrum prediction. In this paper we introduce a HMM-based spectrum prediction algorithm for industrial applications that accurately predicts multiple slots in the future. Traditional HMM prediction approaches use two hidden states enabling the prediction of only one step ahead in the future. This one step is most often not enough due to internal hardware delays that render it outdated. We show in this work that extending the number of hidden states and formulating the prediction problem as a maximum likelihood (ML) classification approach enables a prediction span of multiple slots in the future even with fine spectrum sensing resolution. We verify the suitability of our approach to industrial wireless through extensive simulations that utilize a realistic measurement-based traffic model specifically tailored for industrial automotive settings.

Measuring the natural frequency of buildings and bridges is a possibility to get information about the stiffness of the construction. Decreasing stiffness can be detected be repeatedly measurements. Damaged parts of the construction or too high wood moisture can be reasons for decreasing stiffness. The earlier the failure is detected the better is the chance to repair it with low costs. The method of monitoring by repeatedly measuring the natural frequency is applied at timber bridges, especially on footbridges. As damages due to high wood moisture cannot be seen easily, measuring the natural frequency is a good possibility to detect them and then to repair them. Equations to calculate the natural frequencies regarding the damaged parts are shown and applied to a simple supported beam.

Die ISO 26000 schafft einen international anerkannten Referenzrahmen für die Wahrnehmung gesellschaftlicher Verantwortung durch Organisationen aller Art (Unternehmen, staatliche Institutionen, Vereinigungen). Das EFQM-Modell ist ein geeigneter Referenzrahmen, um eine Organisation so zu gestalten, dass die Unternehmensziele nachhaltig erreicht werden unter Einhaltung der gesetzlichen Vorgaben und der Erfüllung legitimer Anforderungen relevanter Stakeholder.

Die Einführung von cyberphysischen Systemen in der Fertigung wird die Arbeitsbedingungen und Prozesse genauso wie Geschäftsmodelle stark verändern. In der Praxis kann eine wachsende Diskrepanz zwischen Großunternehmen und KMU beobachtet werden. Genau diese Diskrepanz soll die im Folgenden präsentierte Lernfabrik überbrücken, die Unternehmen eine Plattform zum Probieren bietet, die Möglichkeit zur Ausbildung von Studenten und Mitarbeitern schafft und Beratungsangebote bereithält. Zur Umsetzung wird ein integriertes, offenes und standardisiertes Automatisierungskonzept vorgestellt, das einzelne Geräte, ganze Produktionslinien bis hin zu höheren Automatisierungssystemen umfasst und auch eine Community bereitstellt sowie zur Umsetzung neuer Geschäftsmodelle dient.

The person’s heart rate is an important indicator of their health status. A heart rate that is too high or too low could be a sign of several different diseases, such as a heart disorder, obesity, asthma, or many others. Many devices require users to wear the device on their chest or place a finger on the device. The approach presented in this paper describes the principle and implementation of a heart rate monitoring device, which is able to detect the heart rate with high precision with the sensor integrated in a wristband. One method to measure the heart rate is the photoplethysmogram technique. This method measures the change of blood volume through the absorption or reflection of light. A light emitting diode (LED) shines through a thin amount of tissue. A photo-diode registers the intensity of light that traverses the tissue or is reflected by the tissue. Since blood changes its volume with each heartbeat, the photo-diode detects more or less light from the LED. The device is able to measure the heart rate with a high precision, it has low performance and hardware requirements, and it allows an implementation with small micro-controllers.

A method is investigated by which tight bounds on the range of a multivariate rational function over a box can be computed. The approach relies on the expansion of the numerator and denominator polynomials in Bernstein polynomials. Convergence of the bounds to the range with respect to degree elevation of the Bernstein expansion, to the width of the box and to subdivision are proven and the inclusion isotonicity of the related enclosure function is shown.

Three-level inverters are used in electrical drive systems, as grid infeed inverter in PV power plants or as active power line filters. Up to now so called hard switching topologies have been used. A new 'Soft Switching Three Level Inverter (S3L Inverter)' which is now available provides reduced switching losses and higher efficiency. In this paper the S3L inverter is compared with a hard switching T-type inverter topology (H3L inverter). S3L inverters provide higher efficiency and additionally advantages in electromagnetic compatibility due to the soft switching performance, especially when using the 'Super Soft Switching Three Level Inverter (SS3L Inverter)'.

Domain-Specific modelling is increasingly adopted in the software development industry. While textual domain specific languages (DSLs) already have a wide impact, graphical DSLs still need to live up to their full potential. In this paper we describe an approach that reduces the time to create a graphical DSL to hours instead of months. The paper describes a generative approach to the creation of graphical editors for the Eclipse platform. A set of carefully designed textual DSLs together with an EMF meta-model are the input for the generator. The output is an Eclipse plugin for a graphical editor for the intended graphical language. The entire project is made available as open source under the name Spray and is being developed by an active community. This paper focuses on the description of the workflow and provides an introduction into the possibilities through this approach of a graphical modelling environment.

Domain-specific modeling is increasingly adopted by the software development industry. While textual domain-specific languages (DSLs) already have a wide impact, graphical DSLs still need to live up to their full potential. Textual DSLs are usually generated from a grammar or other short textual notations; their development is often cost-efficient. In this paper, we describe an approach to similarly create graphical DSLs from textual notations. The paper describes an approach to generate a graphical node and edge online editor, using a set of carefully designed textual DSLs to fully describe graphical DSLs. Combined with an adequate metamodel, these textual definitions represent the input for a generator that produces a graphical Editor for the web with features such as collaboration, online storage and being always available. The entire project is made available as open source under the name Zeta. This paper focuses on the overall approach and the description of the textual DSLs that can be used to develop graphical modeling languages and editors.

The development of native user interface components is a time consuming and repetitive process, especially for quite simple components like text fields in a form. In order to save time during development an approach is presented in this paper, abstracting the description of the elements into separate files independent from the source code. With aspects from generative and model-driven approaches this leads to simple reusable UI components without the need of deep knowledge in native programming languages.

In this paper we propose a method to determine the active speaker for each time-frequency point in the noisy signals of a microphone array. This detection is based on a statistical model where the speech signals as well as noise signals are assumed to be multivariate Gaussian random variables in the Fourier domain. Based on this model we derive a maximum-likelihood detector for the active speaker. The decision is based on the a posteriori signal to noise ratio (SNR) of a speaker dependent max-SNR beamformer.

This letter introduces signal constellations based on multiplicative groups of Eisenstein integers, i.e., hexagonal lattices. These sets of Eisenstein integers are proposed as signal constellations for generalized spatial modulation. The algebraic properties of the new constellations are investigated and a set partitioning technique is developed. This technique can be used to design coded modulation schemes over hexagonal lattices.