Liste der Fachpublikationen

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3D Mass Digitization: A Milestone for Archeological Documentation

2017

VAR. Virtual Archaeology Review [online], Vol.8 (2017), 16, pp. 1-11

In the heritage field the demand for fast and efficient 3D digitization technologies for historic remains is increasing. Besides, 3D digitization has proved to be a promising approach to enable precise reconstructions of objects. Yet, unlike the digital acquisition of cultural goods in 2D widely used today, 3D digitization often still requires a significant investment of time and money. To make it more widely available to heritage institutions, the Competence Center for Cultural Heritage Digitization at the Fraunhofer Institute for Computer Graphics Research IGD has developed CultLab3D, the world's first fully automatic 3D mass digitization facility for collections of three-dimensional objects. CultLab3D is specifically designed to automate the entire 3D digitization process thus allowing users to scan and archive objects on a large-scale. Moreover, scanning and lighting technologies are combined to capture the exact geometry, texture, and optical material properties of artefacts to produce highly accurate photo-realistic representations. The unique setup allows shortening the time needed for digitization to several minutes per artefact instead of hours, as required by conventional 3D scanning methods.

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Getto, Roman; Merz, Johannes; Kuijper, Arjan; Fellner, Dieter W.

3D Meta Model Generation with Application in 3D Object Retrieval

2017

Mao, Xiaoyang (Ed.) et al.: CGI 2017. Proceedings of the Computer Graphics International Conference. New York: ACM, 2017. (ACM International Conference Proceedings Series (ICPS) 1368), 6 p.

Computer Graphics International (CGI) <34, 2017, Yokohama, Japan>

In the application of 3D object retrieval we search for 3D objects similar to a given query object. When a user searches for a certain class of objects like 'planes' the results can be unsatisfying: Many object variations are possible for a single class and not all of them are covered with one or a few example objects. We propose a meta model representation which corresponds to a procedural model with meta-parameters. Changing the meta-parameters leads to different variations of a 3D object. For the meta model generation a single object is constructed with a modeling tool. We automatically extract a procedural representation of the object. By inserting metaparameters we generate our meta model. The meta model defines a whole object class. The user can choose a meta model and search for all objects similar to any instance of the meta model to retrieve all objects of a certain class from a 3D object database. We show that the retrieval precision is signifcantly improved using the meta model as retrieval query.

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3D-printed Electrodes for Electric Field Sensing Technologies

2017

Darmstadt, TU, Master Thesis, 2017

Electrical field sensing and capacitive sensing have been an intensively explored research topic for over a century. Combined with the rising popularity of rapid prototyping technologies, like affordable all- in-one micro-controller boards and especially fused filament fabrication 3D-printing, new possibilities occur. 3D-printing drives the ambitions of custom designed objects with fully integrated and unobtrusive electronics. Conductive 3D-printing materials (filaments) can be used to create electrodes for electrical field sensing. These electrodes can be 3D-printed as an integral part into the overall object. However, none of the previous work examines the properties of these conductive materials, the chosen 3D-printing configurations, and patters regarding their sensing performance and costs. This thesis provides a first insight into the interdependency between the chosen 3D- printing parameters and the overall sensing performance. For this, 30 3D-printed electrodes were created from graphene filament and evaluated against one copper electrode, and a placebo electrode. The evaluation was performed by a custom made measuring toolkit, the CapLiper, which was also evaluated for proper sensing behavior. The results show, that 3D-printed electrodes can compete with the sensing performance of copper electrodes, with some exceeding its performance. Using these results, as well as lessons learned in creating two different prototypes, the thesis establishes best practice and gives an outlook on potential future work in this domain.

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Acceleration of 3D Mass Digitization Processes: Recent Advances and Challenges

2017

Ioannides, Marinos (Ed.) et al.: Mixed Reality and Gamification for Cultural Heritage. Springer International Publishing, 2017, pp. 99-128

In the heritage field, the demand for fast and efficient 3D digitization technologies for historic remains is increasing. Besides, 3D has proven to be a promising approach to enable precise reconstructions of cultural heritage objects. Even though 3D technologies and postprocessing tools are widespread and approaches to semantic enrichment and Storage of 3D models are just emerging, only few approaches enable mass capture and computation of 3D virtual models from zoological and archeological findings. To illustrate how future 3D mass digitization systems may look like, we introduce CultLab3D, a recent approach to 3D mass digitization, annotation, and archival storage by the Competence Center for Cultural Heritage Digitization at the Fraunhofer Institute for Computer Graphics Research IGD. CultLab3D can be regarded as one of the first feasible approaches worldwide to enable fast, efficient, and cost-effective 3D digitization. lt specifically designed to automate the entire process and thus allows to scan and archive large amounts of heritage objects for documentation and preservation in the best possible quality, taking advantage of integrated 30 visualization and annotation within regular Web browsers using technologies such as WebGI and X3D.

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Accurate Physics-Based Registration for the Outcome Validation of Minimal Invasive Interventions and Open Liver Surgeries

2017

IEEE Transactions on Biomedical Engineering, Vol.64 (2017), 2, pp. 362-371

The purpose of this paper is to present an outcome validation tool for tumor radiofrequency (RF) ablation and resection. Methods: Intervention assessment tools require an accurate registration of both pre- and postoperative computed tomographies able to handle big deformations. Therefore, a physics-based method is proposed with that purpose. To increase the accuracy both automatically detected internal and surface physical landmarks are incorporated in the registration process. Results: The algorithm has been evaluated in 25 clinical datasets containing RF ablations, resections, and patients with recurrent tumors. The achieved accuracy is 1.2 mm measured as mean internal distance between vessel landmarks and a positive predictive value of 0.95. The quantitative and qualitative results of the outcome validation tool show that in 50% of the cases tumors were only partially covered by the treatment. Conclusion: The use of internal and surface landmarks combined with a physics-based registration method increases the accuracy of the results compared to the accuracy of state of the art methods. An accurate outcome validation tool is important in order to certify that the tumor and its safety margin were fully covered by the treatment. Significance: An accurate outcome validation tool can result in a decrease of the tumor recurrence rate.

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Gangatharan, Dinesh Vaithyalingam; Kupnik, Mario (Betreuer); Fu, Biying (Betreuer)

Activity Recognition On Unmodified Consumer Smartphones Via Active Ultrasonic Sensing

2017

Darmstadt, TU, Master Thesis, 2017

Sensor miniaturisation and streaming classification techniques can be used to recognize human behaviours and contexts. This is extremely valuable to realize smart environments, e.g. to support healthy and independent living. The most important parameters to sense include indoor location, gestures, or emergencies like falls. Up to now, activity recognition systems face a number of sensitive drawbacks. For example, camera-based systems induce privacy issues and are costly to deploy. Body-worn systems are inconvenient to wear over long periods of time. Highly visible systems may introduce social stigma and modify the well-known living environment. In this project, we explore the possibility for the use of a new, unobtrusive, physical principle to sense and recognize human activities using off-the-shelf smart-phone. A person's smart-phone is a cornucopia of information. The huge variety of sensors in today's mobile phones makes these devices a prime target for human activity recognition. Our novel approach is to develop a novel activity recognizing system using an unmodified smart-phone. We profit from integrated microphones and loudspeakers without additional hardware components needed. The advantage of this system is therefore that it can be easily installed on a smart-phone and put into action. An android application has already been developed which is able to send a high frequency sound in the near ultrasound range, e.g. 20 kHz. Using the received echo from the microphone, the information caused by movement in midair around the device will be extracted. In this thesis we intend to improve the performance of the existing system with respect to noise cancellation and other classification schemes. In this thesis, we present an android application called Trainer for complex activity recognition. It is built on ultrasense [8], a mobile application that capitalizes the characters of ultrasound to inspect the surrounding environment. The application is able to send a high frequency signal in the near ultrasound range, e.g. 20 kHz. Using the received echo from the microphone, the information caused by movement in midair around the device will be extracted. Complex activities tagged under home exercises are evaluated using micro-Doppler signatures [mD-signatures]. We propose an algorithm to classify a set of exercises carried out by the user and show that using the Support vector machine classifier we are able to obtain an accuracy of 85% using Principal component analysis and a signature feature introduced in this thesis as a feature.

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Braun, Andreas; Wichert, Reiner

Ambient Intelligence: 13th European Conference, AmI 2017

2017

European Conference on Ambient Intelligence (AmI) <13, 2017, Malaga, Spain>

Lecture Notes in Computer Science (LNCS) 10217

The AmI 2017 conference solicited contributions with the themes of: - Enabling Technologies, Methods and Platforms - Objectives and Approaches of Ambient Intelligence and Internet of Things - From Information Design to Interaction and Experience Design - Application Areas of AmI and IoT

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Applying the PROSA Reference Architecture to Enable the Interaction between the Worker and the Industrial Robot: Case Study: One Worker Interaction with a Dual-Arm Industrial Robot

2017

Herik, Jaap van den (Ed.) et al.: ICAART 2017 Vol. 1 : Proceedings of the 9th International Conference on Agents and Artificial Intelligence. SciTePress, 2017, pp. 190-199

International Conference on Agents and Artificial Intelligence (ICAART) <9, 2017, Porto, Portugal>

Involving an industrial robot in a close physical interaction with the worker became quite possible, as a result of the availability of different collaborative industrial robots in the market. The physical cooperation between the industrial robot and the worker usually done under the umbrella of the flexible manufacturing paradigm, where both the industrial robot and the worker need to change their tasks fast and efficiently, to cope with the changes in the manufacturing process. This means that a reliable manufacturing control system must stand behind this physical interaction to achieve the proper communication interaction. A holonic control architecture is an ideal solution for this problem. Therefore, during this research we study the most commonly applied model of the holonic control architecture, then we apply this architecture on our case study, where one worker cooperates with a dual-arm industrial robot to build and produce any new product. Also the research uses the worker's hand gesture recognition as a method to interact with the industrial robot during the execution of a cooperative production scenario.

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Approaches and Challenges in the Visual-interactive Comparison of Human Motion Data

2017

Linsen, Lars (Ed.) et al.: IVAPP 2017. Proceedings : 8th International Conference on Information Visualization Theory and Applications (VISIGRAPP 2017 Volume 3). SciTePress, 2017, pp. 217-224

International Conference on Information Visualization Theory and Applications (IVAPP) <8, 2017, Porto, Portugal>

Many analysis goals involving human motion capture (MoCap) data require the comparison of motion patterns. Pioneer works in visual analytics recently recognized visual comparison as substantial for visual-interactive analysis. This work reflects the design space for visual-interactive systems facilitating the visual comparison of human MoCap data, and presents a taxonomy comprising three primary factors, following the general visual analytics process: algorithmic models, visualizations for motion comparison, and back propagation of user feedback. Based on a literature review, relevant visual comparison approaches are discussed. We outline remaining challenges and inspiring works on MoCap data, information visualization, and visual analytics.

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Behr, Johannes; Blach, Roland; Bockholt, Ulrich; Harth, Andreas; Hoffmann, Hilko; Huber, Manuel; Käfer, Tobias; Keppmann, Felix Leif; Pankratz, Frieder; Rubinstein, Dmitri; Schubotz, René; Vogelgesang, Christian; Voss, Gerrit

ARVIDA-Referenzarchitektur: Ressourcen-orientierte Architekturen für die Anwendungsentwicklung Virtueller Techniken

2017

Schreiber, Werner (Ed.) et al.: Web-basierte Anwendungen Virtueller Techniken: Das ARVIDA-Projekt - Dienste-basierte Software-Architektur und Anwendungsszenarien für die Industrie. Berlin: Springer Vieweg, 2017, pp. 117-191

Die ARVIDA-Referenzarchitektur ist ein zentrales Element und Ergebnis des ARVIDA- Projektes. Sie ermöglicht es, mit etablierten Technologien und Konzepten aus dem Web-Umfeld heterogene VT-Systemlandschaften in integrierten, sehr weitgehend plattformunabhängigen VT-Anwendungen effizient zu nutzen. Die Referenzarchitektur nutzt und adaptiert das Prinzip der RESTful-Web-Services sowie die darauf aufbauenden Linked-Data Konzepte, um interoperable, leicht erweiterbare und modulare VTAnwendungen zu bauen. Die nachfolgenden Abschnitte beschreiben die Grundprinzipien und spezifischen Erweiterungen im Detail.

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Alvarado, Pablo; Bockholt, Ulrich; Canzler, Ulrich; Herbort, Steffen; Heuser, Nicolas; Keitler, Peter; Krzikalla, Roland; Olbrich, Manuel; Prager, André; Schröder, Frank; Schwerdt, Jörg; Willneff, Jochen; Zürl, Konrad

ARVIDA-Technologien

2017

Schreiber, Werner (Ed.) et al.: Web-basierte Anwendungen Virtueller Techniken: Das ARVIDA-Projekt - Dienste-basierte Software-Architektur und Anwendungsszenarien für die Industrie. Berlin: Springer Vieweg, 2017, pp. 193-217

Dieses Kapitel beschreibt Technologien im Kontext von ARVIDA, die über die allgemeine Beschreibung von Technologien aus Kap. 2 hinausgehen. Eine der Hürden für den produktiven Einsatz von VT ist der Mangel an robusten, markerlosen Trackingsystemen. Hier wurden im Rahmen des Projektes essentielle Fortschritte gemacht. Auch bei der Gestenerkennung konnten im Rahmen der Interaktion in einer Sitzkiste wesentliche Verbesserungen erzielt werden. Die Vermessung von Geodaten ist eine Grundvoraussetzung für Anwendungen im Digitalen Fahrzeugerlebnis. Hier wurden ebenfalls deutliche Fortschritte erzielt. Schließlich ist zu erwähnen, dass die vorgestellten Technologien als Dienste der Referenzarchitektur bereitgestellt werden, um den Austausch von Technologien einfach zu gestalten.

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Rus, Silvia; Caliz, Doris; Braun, Andreas; Engler, Anne; Schulze, Eva

Assistive Apps for Activities of Daily Living Supporting Persons with Down's Syndrome

2017

Journal of Ambient Intelligence and Smart Environments, Vol.9 (2017), 5, pp. 611-623

Supporting persons with Down's Syndrome in their daily activities using ICT is a key element in further advancing their independence and integration into society. The POSEIDON project embraces this goals and develops technology which creates adjustable and personalizable assistive systems. We present a system for Money-Handling Training and assistance for shopping. In this paper we present results of evaluating the Money-Handling Training App in different pilot studies and work-shops, with a larger group of persons with Down's Syndrome, comparing different interaction devices like tablet, personal computer and interactive table. Furthermore, we present evaluation results for the Shopping App.

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Frank, Sebastian; Kuijper, Arjan

AuthentiCap - A Touchless Vehicle Authentication and Personalization System

2017

Braun, Andreas (Ed.) et al.: Ambient Intelligence : 13th European Conference, AmI 2017. Springer, 2017. (Lecture Notes in Computer Science (LNCS) 10217), pp. 46-63

European Conference on Ambient Intelligence (AmI) <13, 2017, Malaga, Spain>

Current authentication systems in vehicles use portable keys or biometric and/or touch based inputs. They can be outwitted by stealing the keys or by copying the biometric information and analyzing the touch marks. This has to be inhibited, since vehicles are not only an expensive property, that would be lost in non-authenticated hands, but wrong permitted access also can unleash heavy machine power to inexperienced drivers or even people without a driver's license. We present a system that authenticates drivers and unlocks personalization features without any portable keys or touching. Moreover, it is invisibly integrated into a vehicle structure, the steering wheel. In contrast to biometric authentication, the password pattern is adjustable and changeable. With the presented system, vehicle manufactures are able to install driver authentication systems without any visible design changes. The manufacturer thus provides more freedom and responsibility to the driver by giving him the option to choose his own unlock pattern. Still, the security is increased by avoiding common vulnerabilities like smudge attacks, the stealing of keys, or copying of biometric data. Our experiments show excellent recognition rates for multiple string patterns. A small user study shows that our system achieves 86% accuracy for inexperienced users, up to 96% for experienced ones. The users appreciated the easy of use.

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Fina, Kenten; Kuijper, Arjan (Betreuer); Getto, Roman (Betreuer)

Automated Detection of Significant Parameters in Procedural 3D Models

2017

Darmstadt, TU, Bachelor Thesis, 2017

This bachelor thesis present an approach to automatically detect significant parameters in a procedural model. For the distinction of significant and insignificant parameters we present both a static version and a method using machine learning. In the process parameters are grouped, which represent symmetries or other relations in the model. Additionally we allow the user to adapt the selection of significant parameters to his needs. For this purpose we support the user by visualizing the changes of a parameter. Furthermore a hierarchical arrangement of the parameters is done to give the user an overview of all design possibilities. Subsequently, we show how ranges for the selected parameters can be calculated, which retain the object.

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Jung, Florian; Biebl-Rydlo, Medea; Daisne, Jean-François; Wesarg, Stefan

Automatic Sentinel Lymph Node Localization in Head and Neck Cancer Using a Coupled Shape Model Algorithm

2017

Cardoso, Jorge M. (Ed.) et al.: Computer Assisted and Robotic Endoscopy and Clinical Image-Based Procedures : 4th International Workshop, CARE 2017 and 6th International Workshop, CLIP 2017. Held in Conjunction with MICCAI 2017.. Berlin, Heidelberg, New York: Springer, 2017. (Lecture Notes in Computer Science (LNCS) 10550), pp. 133-140

The localization and analysis of the sentinel lymph node for patients diagnosed with cancer, has significant influence on the prognosis, outcome and treatment of the disease. We present a fully automatic approach to localize the sentinel lymph node and additional active nodes and determine their lymph node level on SPECT-CT data. This is a crucial prerequisite for the planning of radiation therapy or a surgical neck dissection. Our approach was evaluated on 17 lymph nodes. The detection rate of the lymph nodes was 94%; and 88% of the lymph nodes were correctly assigned to their corresponding lymph node level. The proposed algorithm targets a very important topic in clinical practice. The first results are already very promising. The next step has to be the evaluation on a larger data set.

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Hartwig, Katrin; Sakas, Georgios (Betreuer); Oyarzun Laura, Cristina (Betreuer)

Automatische Segmentierung der Nasenscheidewand auf Basis von computertomographischen Bilddaten

2017

Darmstadt, TU, Bachelor Thesis, 2017

Im Kontext der Nasenheilkunde spielt die Segmentierung der Nasenscheidewand anhand von computertomographischen Bildern eine wichtige Rolle für Diagnose, präoperative Planung und Behandlung. Aktuelle Verfahren stützen sich zumeist auf manuelle Segmentierung, welche für den medizinischen Alltag zu zeitintensiv ist. In der vorliegenden Bachelorarbeit wurde daher ein vollautomatisches Verfahren entwickelt, welches an die anatomischen Besonderheiten und computationellen Herausforderungen der Nasenscheidewand adaptiert ist. Dabei wurde eine Kombination aus Musterdetektion und Slice-based Propagation angewandt. Die Evaluation anhand von 19 Datensätzen zeigt mit durchschnittlich 0,78 Sekunden pro CT-Bild eine deutliche Beschleunigung im Vergleich zu manuellen Verfahren und erzielt auch im Bezug auf die Genauigkeit der Segmentierung mit einem durchschnittlichen DSC-Wert von 0,8665 annehmbare Ergebnisse.

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Bauer, Johann; Urban, Bodo (Betreuer); Aehnelt, Mario (Betreuer)

Automatisches Generieren von Instruktionen im Plant@Hand Montageassistenzsystem

2017

Rostock, Univ., Bachelor Thesis, 2017

Das Plant@Hand-Montageassistenzsystem unterstützt Montagearbeiter bei der variantenreichen Fertigung von Kleinstserien. Das Ziel der vorliegenden Bachelorarbeit war die Entwicklung eines Konzepts, das die Methoden des Cognitive-Apprenticeship Modells zur automatisierten Anpassung dieser Assistenz an den Montagearbeiter nutzt. Ein Teil des entwickelten Konzepts wurde prototypisch im Plant@Hand-Montageassistenzsystem umgesetzt.

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Sagare, Anagha; Kuijper, Arjan (Betreuer); Fu, Biying (Betreuer)

Best Practices to Visualize Activity Data in Mobile Apps

2017

Darmstadt, TU, Master Thesis, 2017

Physical activity and exercise are essential factors to live a healthy life. Fitness trackers have great potential to assist individuals in making healthy changes to their lifestyle. A variety of fitness trackers are available in the market such as fitness apps based on mobile platform, wearable sensors (e.g. smartwatch, armband, wristband), balancing boards (e.g. Wii fit) etc. In this thesis, the focus is on fitness apps based on mobile platform. These apps provide different information and features to the user such as a summary of the physical activity performed, feedback of the activity (e.g. through virtual trainer), exercise plans according to the user's workout routine, user's achievements and many more. Also, fitness apps aim to present a lot of statistical data to the users regarding their current or previous physical activity which may range from days to years. To visualize this data, visual designs such as maps, graphs, images are used. However, very little is known about such visualization schemes and design strategies for fitness data w.r.t engaging users. Furthermore, it is important to know if the provided features in the app are useful. The main objective of this study is to evaluate different visualization schemes used in visualizing fitness data and to explore usability requirements, motivating factors for using mobile fitness apps. For this purpose, a profound research is done in three phases. The first phase focuses on finding expectations of a user from fitness app through a short primary survey in University Gym, the second phase includes designing an extensive user survey and fitness app mock-ups based on the survey findings in the first phase. In the third phase, the designed mock-ups are evaluated by means of the user survey designed in second phase and the survey results are analyzed using statistical test. The study reveals that users find some visualization schemes very useful whereas they do not prefer some visualization schemes at all. Same is the case observed for motivational features e.g. ranking, rewards and other functionalities of the app e.g. workout summary, nutrition information. This thesis concludes with best practices for designing visualization schemes and analysis of user requirements for mobile fitness applications such as integrated feedback, home screen design of the app and some features like data sharing, data export etc. These findings show the way to develop highly usable fitness applications with user-centric design.

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Gao, Shan; Ye, Qixiang; Xing, Junliang; Kuijper, Arjan; Han, Zhenjun; Jiao, Jianbin; Ji, Xiangyang

Beyond Group: Multiple Person Tracking via Minimal Topology-Energy-Variation

2017

IEEE Transactions on Image Processing, Vol.26 (2017), 12, pp. 5575-5589

Tracking multiple persons is a challenging task when persons move in groups and occlude each other. Existing group-based methods have extensively investigated how to make group division more accurately in a tracking-by-detection framework; however, few of them quantify the group dynamics from the perspective of targets' spatial topology or consider the group in a dynamic view. Inspired by the sociological properties of pedestrians, we propose a novel socio-topology model with a topology-energy function to factor the group dynamics of moving persons and groups. In this model, minimizing the topologyenergy- variance in a two-level energy form is expected to produce smooth topology transitions, stable group tracking, and accurate target association. To search for the strong minimum in energy variation, we design the discrete group-tracklet jump moves embedded in the gradient descent method, which ensures that the moves reduce the energy variation of group and trajectory alternately in the varying topology dimension. Experimental results on both RGB and RGB-D data sets show the superiority of our proposed model for multiple person tracking in crowd scenes.

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CAE/VR Integration - A Path to Follow? A Validation Based on Industrial Use

2017

Zoltay Paprika, Zita (Ed.) et al.: ECMS 2017 : 31st European Conference on Modelling and Simulation, pp. 436-445

European Conference on Modelling and Simulation (ECMS) <31, 2017, Budapest, Hungary>

Numerical simulations have become crucial during the product development process (PDP) for predicting and validating different properties of new products as well as the simulation of various kinds of natural phenomena. Especially the engineering domain (CAE - Computer Aided Engineering), is seeking for new ICT solutions to cover broad ranges of physical simulations. Virtual Reality (VR) has matured in the past allowing a rapid consolidation of information and decision-making through visualization and experience. These new man machine interfaces offer advanced interaction possibilities with the digital domain and allow engineers to variate over several hypothesis. This enlightened ideas to deploy VR for "what-if-scenarios" also in the CAE domain. However, while CAD/VR integration has been sufficiently researched, the integration of CAE into VR is still facing a long road ahead. Despite recent criticism that the application of VR technology has been considered unnecessary in CAE, this paper aims to refute this by presenting methodologies for linear static FEM analysis allowing "what-if-scenarios" within interactive environments. It validates the elaborated methodologies and advantages of VR front ends by an evaluation performed within industrial engineering departments.

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CapSoles: Who Is Walking on What Kind of Floor?

2017

Association for Computing Machinery (ACM): MobileHCI 2017 : Proceedings of the 19th International Conference on Human-Computer Interaction with Mobile Devices and Services. New York: ACM, 2017, 14 p.

International Conference on Human-Computer Interaction with Mobile Devices and Services (MobileHCI) <19, 2017, Vienna, Austria>

Foot interfaces, such as pressure-sensitive insoles, still yield unused potential such as for implicit interaction. In this paper, we introduce CapSoles, enabling smart insoles to implicitly identify who is walking on what kind of floor. Our insole prototype relies on capacitive sensing and is able to sense plantar pressure distribution underneath the foot, plus a capacitive ground coupling effect. By using machine-learning algorithms, we evaluated the identification of 13 users, while walking, with a confidence of ~95% after a recognition delay of ~1s. Once the user's gait is known, again we can discover irregularities in gait plus a varying ground coupling. While both effects in combination are usually unique for several ground surfaces, we demonstrate to distinguish six kinds of floors, which are sand, lawn, paving stone, carpet, linoleum, and tartan with an average accuracy of ~82%. Moreover, we demonstrate the unique effects of wet and electrostatically charged surfaces.

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Change Detection in Crowded Underwater Scenes Via an Extended Gaussian Switch Model Combined with a Flux Tensor Pre-segmentation

2017

Imai, Francisco (Ed.) et al.: VISAPP 2017. Proceedings : 12th International Conference on Computer Vision Theory and Applications (VISIGRAPP 2017 Volume 4). SciTePress, 2017, pp. 405-415

International Conference on Computer Vision Theory and Applications (VISAPP) <12, 2017, Porto, Portugal>

In this paper a new approach for change detection in videos of crowded scenes is proposed with the extended Gaussian Switch Model in combination with a Flux Tensor pre-segmentation. The extended Gaussian Switch Model enhances the previous method by combining it with the idea of the Mixture of Gaussian approach and an intelligent update scheme which made it possible to create more accurate background models even for difficult scenes. Furthermore, a foreground model was integrated and could deliver valuable information in the segmentation process. To deal with very crowded areas in the scene - where the background is not visible most of the time - we use the Flux Tensor to create a first coarse segmentation of the current frame and only update areas that are almost motionless and therefore with high certainty should be classified as background. To ensure the spatial coherence of the final segmentations, the N2Cut approach is added as a spatial model after the background subtraction step. The evaluation was done on an underwater change detection datasets and showed significant improvements over previous methods, especially in the crowded scenes.

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Ceneda, Davide; Gschwandtner, Theresia; May, Thorsten; Miksch, Silvia; Schulz, Hans-Jörg; Streit, Marc; Tominski, Christian

Characterizing Guidance in Visual Analytics

2017

IEEE Transactions on Visualization and Computer Graphics, Vol.23 (2017), 1, pp. 111-120

IEEE Conference on Visual Analytics Science and Technology (VAST) <11, 2016, Baltimore, USA>

Visual analytics (VA) is typically applied in scenarios where complex data has to be analyzed. Unfortunately, there is a natural correlation between the complexity of the data and the complexity of the tools to study them. An adverse effect of complicated tools is that analytical goals are more difficult to reach. Therefore, it makes sense to consider methods that guide or assist users in the visual analysis process. Several such methods already exist in the literature, yet we are lacking a general model that facilitates in-depth reasoning about guidance. We establish such a model by extending van Wijk's model of visualization with the fundamental components of guidance. Guidance is defined as a process that gradually narrows the gap that hinders effective continuation of the data analysis. We describe diverse inputs based on which guidance can be generated and discuss different degrees of guidance and means to incorporate guidance into VA tools. We use existing guidance approaches from the literature to illustrate the various aspects of our model. As a conclusion, we identify research challenges and suggest directions for future studies. With our work we take a necessary step to pave the way to a systematic development of guidance techniques that effectively support users in the context of VA.

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Bernard, Jürgen; Dobermann, Eduard; Sedlmair, Michael; Fellner, Dieter W.

Combining Cluster and Outlier Analysis with Visual Analytics

2017

Sedlmaier, Michael (Ed.) et al.: EuroVA 2017 : EuroVis Workshop on Visual Analytics. Goslar: Eurographics Association, 2017, pp. 19-23

International EuroVis Workshop on Visual Analytics (EuroVA) <8, 2017, Barcelona, Spain>

Cluster and outlier analysis are two important tasks. Due to their nature these tasks seem to be opposed to each other, i.e., data objects either belong to a cluster structure or a sparsely populated outlier region. In this work, we present a visual analytics tool that allows the combined analysis of clusters and outliers. Users can add multiple clustering and outlier analysis algorithms, compare results visually, and combine the algorithms' results. The usefulness of the combined analysis is demonstrated using the example of labeling unknown data sets. The usage scenario also shows that identified clusters and outliers can share joint areas of the data space.

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CSG Ray Tracing Revisited: Interactive Rendering of Massive Models Made of Non-planar Higher Order Primitives

2017

Cláudio, Ana Paula (Ed.) et al.: GRAPP 2017. Proceedings : 12th International Conference on Computer Graphics Theory and Applications (VISIGRAPP 2017 Volume 1). SciTePress, 2017, pp. 258-265

International Conference on Computer Graphics Theory and Applications (GRAPP) <12, 2017, Porto, Portugal>

In many scientific and engineering areas, CAD models are constructed by combining simple primitives using Boolean set operations. Rendering such a dataset usually requires a preprocess, where the surface of the CAD model is approximated by an often highly complex triangle mesh. Real-time ray tracing provides an alternative to triangle rasterization as it allows for the direct visualization of (higher-order) solid and planar primitives without having to triangulate them. Additionally, Boolean compositing operations can be performed implicitly per ray, primitives have low storage requirements, and curved surfaces appear pixel-accurate. In this paper we demonstrate these properties using massive real-world CAD models.