Refine
Year of publication
- 2017 (92) (remove)
Document Type
- Conference Proceeding (92) (remove)
Conference Type
- Konferenzartikel (62)
- Konferenz-Abstract (22)
- Konferenz-Poster (3)
- Sonstiges (3)
- Konferenzband (2)
Keywords
- CST (4)
- HF-Ablation (4)
- CRT (3)
- RoboCup (3)
- Gamification (2)
- IVD (2)
- Affective Computing (1)
- Aktivierung (1)
- Arbeitswissenschaft (1)
- Computer Games (1)
Institute
- Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019) (40)
- Fakultät Maschinenbau und Verfahrenstechnik (M+V) (27)
- Fakultät Wirtschaft (W) (13)
- Fakultät Medien und Informationswesen (M+I) (bis 21.04.2021) (12)
- ivESK - Institut für verlässliche Embedded Systems und Kommunikationselektronik (11)
- ACI - Affective and Cognitive Institute (4)
- WLRI - Work-Life Robotics Institute (4)
- Zentrale Einrichtungen (2)
- INES - Institut für nachhaltige Energiesysteme (1)
Open Access
- Open Access (47)
- Closed Access (40)
- Bronze (6)
- Closed (4)
- Grün (1)
A novel approach of a testbed for embedded networking nodes has been conceptualized and implemented. It is based on the use of virtual nodes in a PC environment, where each node executes the original embedded code. Different nodes are running in parallel and are connected via so-called virtual interfaces. The presented approach is very efficient and allows a simple description of test cases without the need of a network simulator. Furthermore, it speeds up the process of developing new features.
In recent years, the additive manufacturing processes have rapidly developed. The additive manufacturing processes currently present a high-performance alternative to conventional manufacturing methods. In particular, they offer the opportunity of previously hardly imaginable design freedom, i.e. the implementation of complex forms and geometries. This capability can, for example, be applied in the development of especially light but still loadable components in automotive engineering. In addition, waste material is seldom produced in additive manufacturing which benefits a sustainable production of building components. Until now, this design freedom was barely used in the construction of technical components and products because, in doing so, both specific design guidelines for additive manufacturing and complex strength calculations must be simultaneously observed. Yet in order to fully take advantage of the additive manufacturing potential, the method of topology optimization, based on FEM simulation, suggests itself. It is with this method that components that are precisely matched and are especially light, thereby also resource-saving, can be produced. Current literature research indicates that this method is used in automotive manufacturing for reducing weight and improving the stability of both individual parts and assembly units. This contribution will study how this development method can be applied in the example of a brake mount from an experimental vehicle. In this, the conventional design is improved by means of a simulation tool for topology optimization in various steps. In an additional processing step, the smoothing of the thus developed component occurs. Finally, the component is generatively manufactured by means of selective laser melting technology. Models are manufactured using binder jetting for the demonstration of the process. It will also be determined how this weight reduction affects the CO2 emissions of a vehicle in use.
Additive manufacturing processes have evolved rapidly in recent years and now offer a wide range of manufacturing technologies and workable materials. This range from plastics and metals to paper and even polymer plaster composites. Due to the layer by layer structure of the components the additive processes have in comparison with conventional manufacturing processes the advantage of freedom of design, that means the simple implementation of complex geometries. Moreover, the additive processes provide the advantage of reduced consumption of resources, since essentially only the material is consumed, which is required for the actual component, since no waste in the form of chips is produced. In order to use these advantages, the potentials of additive manufacturing and the requirements of sustainable design must already be observed in the product development process. So the design of the components and products must be made so as little as possible construction and supporting material is required for the generative production and therefore little resources are consumed. Also, all steps of the additive manufacturing process must be considered properly, that includes the post processing. This allows components be designed so that for instance the effort for removing the support structure is considerably reduced. This leads to a significant reduction in manufacturing time and thus energy consumption. The implementation of these potentials in product development can be demonstrated by means of a multiple-stages model. A case study shows how this model is applied in the training of Master students in the field of product development. In a workshop the students work as a group while implementing the task of developing a miniature racing car under the rules of sustainable design in compliance with the boundary conditions for an additive manufacturing. In this case, Fused Deposition Modelling FDM using plastics as a building material is applied. The results show how the students have dealt with the different requirements and how they have implemented them in product development and in the subsequent additive manufacturing.
The present-day methods of numerical simulation offer a great variety of options for optimizing metal forming processes. Although it is possible to simulate complex forming processes, the results are typically available only as 2D projections on screens. Some forming processes have reached a level of complexity beyond the level of spatial sense, which makes it necessary to use physical 3D representations to develop a deeper understanding of the material flow, microstructural processes, process and design limits, or to design the required tooling. Physical 3D models can be produced in a short amount of time using 3D printing, and indexed with a wide range of colors. In this paper, the additive manufacturing of 3D color models based on simulation results are explored by means of examples from metal forming. Different 3D-printing processes are compared on the basis of quality as well as technical and economic criteria. Other examples from the fields joining by upset-bulging of tubes and microstructure simulation are also analyzed. This paper discusses the possibilities offered by the rapid progress and wide availability of 3D printers for the design and optimization of complex metal forming processes.
Architecture models are an essential component of the development process and enable a physical representation of virtual designs. In addition to the conventional methods of model production using the machining of models made of wood, metal, plastic or glass, a number of additive manufacturing processes are now available. These new processes enable the additive manufacturing of architectural models directly from CAAD or BIM data. However, the boundary conditions applicable to the ability to manufacture models with additive manufacturing processes must also be considered. Such conditions include the minimum wall thickness, which depends on the applied additive manufacturing process and the materials used. Moreover, the need for the removal of support structures after the additive manufacturing process must also be considered. In general, a change in the scale of these models is only possible at very high effort. In order to allow these restrictions to be adequately incorporated into the CAAD model, this contribution develops a parametrized CAAD model that allows such boundary conditions to be modified and adapted while complying with the scale. Usability of this new method is illustrated and explained in detail in a case study. In addition, this article addresses the additive manufacturing processes including subsequent post-processing.
Implementation of lightweight design in the product development process of unmanned aerial vehicles
(2017)
The development and manufacturing of unmanned aerial vehicles (UAVs) require a multitude of design rules. Thereby, additive manufacturing (AM) processes provide a number of significant advantages over conventional production methods, particularly for implementing requirements with regard to lightweight construction and sustainability. A new, promising approach is presented, with which, through the combination of very light structural elements with a ribbed construction, an attached covering by means of foil is used. This contribution develops and presents a development process that is based on various development cycles. Such cycles differ in their effort and scope within the overall development, and may only comprise one part of the development process, or the entire development process. The applicability of this development process is demonstrated within the framework of a comprehensive case study. The aim is to develop an additively manufactured product that is as light as possible in the form of a UAV, along with a sustainable manufacturing process for such product. Finally, the results of this case study are analyzed with regard to the improvement of lightweight construction.
Applications helping us to maintain the focus on work are called “Zenware” (from concentration and Zen). While form factors, use cases and functionality vary, all these applications have a common goal: creating uninterrupted, focused attention on the task at hand. The rise of such tools exemplifies the users’ desire to control their attention within the context of omnipresent distraction. In expert interviews we investigate approaches in the context of attention-management at the workplace of knowledge workers. To gain a broad understanding, we use judgement sampling in interviews with experts from several disciplines. We especially explore how focus and flow can be stimulated. Our contribution has four components: a brief overview on the state of the art (1), a presentation of the results (2), strategies for coping with digital distractions and design guidelines for future Zenware (3) and an outlook on the overall potential in digital work environments (4).
The aim of the smart grid is to achieve more efficient, distributed and secure supply of energy over the traditional power grid by using a bidirectional information flow between the grid agents (e.g. generator node, customer). One of the key optimization problems in smart grid is to produce power among generator nodes with a minimum cost while meeting the customer demand, known as Economic Dispatch Problem (EDP). In recent years, many distributed approaches to solve EDP have been proposed. However, protecting the privacy-sensitive data of individual generator nodes has been largely overlooked in the existing solutions. In this work, we show an attack against an existing auction-based EDP protocol considering a non-colluding semi-honest adversary. We briefly introduce our approach to a practical privacy-preserving EDP solution as our work in progress.
Gamifying rehabilitation is an efficient way to improve motivation and exercise frequency. However, between flow theory, self-determination theory or Bartle's player types there is much room for speculation regarding the mechanics required for successful gamification, which in turn leads to increased motivation. For our study, we selected a gamified solution for motion training (an exergame) where the playful design elements are extremely simple. The contribution is three-fold: we show best practices from the state of the art, present a study analyzing the effects of simple gamification mechanics on a quantitative and on a qualitative level and discuss strategies for playful design in therapeutic movement games.
Designing Authentic Emotions for Non-Human Characters. A Study Evaluating Virtual Affective Behavior
(2017)
While human emotions have been researched for decades, designing authentic emotional behavior for non-human characters has received less attention. However, virtual behavior not only affects game design, but also allows creating authentic avatars or robotic companions. After a discussion of methods to model and recognize emotions, we present three characters with a decreasing level of human features and describe how established design techniques can be adapted for such characters. In a study, 220 participants assess these characters' emotional behavior, focusing on the emotion "anger". We want to determine how reliable users can recognize emotional behavior, if characters increasingly do not look and behave like humans. A secondary aim is determining if gender has an impact on the competence in emotion recognition. The findings indicate that there is an area of insecure attribution of virtual affective behavior not distant but close to human behavior. We also found that at least for anger, men and women assess emotional behavior equally well.
We present the design outline of a context-aware interactive system for smart learning in the STEM curriculum (science, technology, engineering, and mathematics). It is based on a gameful design approach and enables "playful coached learning" (PCL): a learning process enriched by gamification but also close to the learner's activities and emotional setting. After a brief introduction on related work, we describe the technological setup, the integration of projected visual feedback and the use of object and motion recognition to interpret the learner's actions. We explain how this combination enables rapid feedback and why this is particularly important for correct habit formation in practical skills training. In a second step, we discuss gamification methods and analyze which are best suited for the PCL system. Finally, emotion recognition, a major element of the final PCL design not yet implemented, is briefly outlined.
In this paper we show that a model-free approach to learn behaviors in joint space can be successfully used to utilize toes of a humanoid robot. Keeping the approach model-free makes it applicable to any kind of humanoid robot, or robot in general. Here we focus on the benefit on robots with toes which is otherwise more difficult to exploit. The task has been to learn different kick behaviors on simulated Nao robots with toes in the RoboCup 3D soccer simulator. As a result, the robot learned to step on its toe for a kick that performs 30% better than learning the same kick without toes.
Within this work, the benefits of using predictive control methods for the operation of Adsorption Cooling Machines (ACMs) are shown on a simulation study. Since the internal control decisions of series-manufactured ACMs often cannot be influenced, the work focuses on optimized scheduling of an ACM considering its internal functioning as well as forecasts for load and driving energy occurrence. For illustration, an assumed solar thermal climate system is introduced and a system model suitable for use within gradient-based optimization methods is developed. The results of a system simulation using a conventional scheme for ACM scheduling are compared to the results of a predictive, optimization-based scheduling approach for the same exemplary scenario of load and driving energy occurrence. The benefits of the latter approach are shown and future actions for application of these methods for system control are addressed.
Our university carries out various research projects. Among others, the project Schluckspecht is an interdisciplinary work on different ultra-efficient car concepts for international contests. Besides the engineering work, one part of the project deals with real-time data visualization. In order to increase the efficiency of the vehicle, an online monitoring of the runtime parameters is necessary. The driving parameters of the vehicle are transmitted to a processing station via a wireless network connection. We plan to use an augmented reality (AR) application to visualize different data on top of the view of the real car. By utilizing a mobile Android or iOS device a user can interactively view various real-time and statistical data. The car and its components are meant to be augmented by various additional information, whereby that information should appear at the correct position of the components. An engine e.g. could show the current rpm and consumption values. A battery on the other hand could show the current charge level. The goal of this paper is to evaluate different possible approaches, their suitability and to expand our application to other projects at our university.
Die drei großen Hersteller von Cochlea-Implantat (CI)-Systemen ermöglichen es klinischen Audiologen, die Mikrofoneigenschaften der meisten CI-Sprachprozessoren zu prüfen. Dazu können bei diesen Sprachprozessoren Monitorkopfhörer angeschlossen und das/die Mikrofon(e) inklusive eines Teils der Signalvorverarbeitung abgehört werden. Präzise Angaben dazu, mit welchen Stimuli, bei welchem Pegel und nach welchem Kriterium diese Prüfung stattfinden soll, machen die CI-Hersteller nicht. Auf Basis dieser Prüfung soll der Audiologe dann über die Funktion der Mikrofone und damit darüber entscheiden, ob der betreffende Sprachprozessor an den Hersteller eingeschickt wird oder nicht.
Zur Objektivierung der CI-Sprachprozessor-Mikrofon-Prüfung haben wir eine Testbox entwickelt, mit der alle abhörbaren aktuellen CI-Sprachprozessoren der drei großen Hersteller geprüft werden können. Die Box wurde im 3D-Druck-Verfahren hergestellt. Der zu prüfende Sprachprozessor wird in die Messbox eingehängt und über einen darin verbauten Lautsprecher mit definierten Prüfsignalen (Sinustöne unterschiedlicher Frequenz) beschallt. Das Mikrofonsignal wird über das Kabel der Monitorkopfhörer herausgeführt und mit einer Shifting- and Scaling-Schaltung in einen Spannungsbereich transformiert, der für die AD-Wandlung mit einem Mikrokontroller (ATmega1280 verbaut auf einem Arduino Mega) geeignet ist. Derselbe Mikrokontroller übernimmt über einen eigens gebauten DA-Wandler die Ausgabe der Sinustöne über den Lautsprecher. Signalaufnahme und –wiedergabe erfolgen mit jeweils 38,5 kHz Samplingrate. Der für jede Frequenz über mehrere Perioden des Prüfsignals ermittelte Effektivwert wird mit dem Effektivwert, der mit einem neuwertigen Referenzprozessor für diese Frequenz gemessen wurde, verglichen. Die Messergebnisse werden graphisch auf einem Display ausgegeben.
Derzeit läuft eine erste Datenerhebung mit in der Klinik subjektiv auffällig gewordenen CI-Sprachprozessoren, die anschließend in der Messbox untersucht werden. So sollen realistische Schwellen für kritische Abweichungen von den Referenz-Effektivwerten ermittelt werden. Im weiteren Verlauf sollen dann Hit und False Alarm-Raten der subjektiven Prüfung bestimmt werden.
Das normalhörende auditorische System ist in der Lage, interaurale Zeit- bzw. Phasendifferenzen zur verbesserten Signaldetektion im Störgeräusch zu nutzen. Dieses Phänomen wird häufig als binaurale Entmaskierung bezeichnet und ist sowohl bei einfachen Signalen wie Sinustönen, als auch bei Sprachsignalen im Störgeräusch wirksam. Vorangegangene Studien haben gezeigt, dass binaurale Entmaskierung eingeschränkt auch bei bilateralen CI-Trägern beobachtbar ist (Zirn et al., 2016).
Aktuelle Ergebnisse zeigen, dass die binaurale Entmaskierung sensitiv gegenüber der bilateralen CI-Anpassung ist. So lässt sich der Effekt durch tonotopen Abgleich und Herausstellen eines apikalen Feinstrukturkanals modulieren. Steigerungen der binauralen Entmaskierung um bis zu 1,5 dB sind auf diese Weise gegenüber der konventionellen CI-Anpassung möglich. Allerdings variiert der Einfluss der CI-Anpassung interindividuell erheblich.
The ability to detect a target signal masked by noise is improved in normal-hearing listeners when interaural phase differences (IPDs) between the ear signals exist either in the masker or in the signal. To improve binaural hearing in bilaterally implanted cochlear implant (BiCI) users, a coding strategy providing the best possible access to IPDs is highly desirable. Outcomes of a previous study (Zirn, Arndt et al. 2016) revealed that a subset of BiCI users showed improved IPD detection thresholds with the fine structure processing strategy FS4 compared to the constant rate strategy HDCIS using narrowband stimuli. In contrast, little differences between the coding strategies were found for broadband stimuli with regard to binaural speech intelligibility level differences (BILD) as an estimate of binaural unmasking. Compared to normalhearing listeners (7.5 ± 1.2 dB) BILD were small in BiCI users (around 0.5 dB with both coding strategies).
In the present work, we investigated the influence of binaural fitting parameters on BILD. In our cohort of BiCI users many were implanted with electrode arrays differing in length left versus right. Because this length difference typically corresponded to the distance of two electrode contacts the first modification of bilateral fitting was a tonotopic adjustment by deactivation of the most apical electrode contact on the side with the deeper inserted array (tonotopic approach).
The second modification was the isolation of the residual, most apical electrode contacts by deactivation of the basally adjacent electrode contact on each side (tonotopic sparse approach). Applying these modifications, BILD improved by up to 1.5 dB.