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Müller-Wittig, Wolfgang K.

Virtuelle Realität in der Medizin

2017

Kramme, Rüdiger (Ed.): Medizintechnik : Verfahren - Systeme - Informationsverarbeitung. Berlin, Heidelberg, New York: Springer, 2017, pp. 845-854

Die Virtuelle Realität (Virtual Reality, VR) - computergenerierte, dreidimensionale Welten - erlebt heutzutage eine noch nie dagewesene Popularität. Was in den 1980er- und 1990er-Jahren Forschungsinstitutionen und Universitäten vorbehalten war, ist mittlerweile im Massenmarkt angekommen. Dies ist mit Sicherheit auf die rapide Entwicklung und Verfügbarkeit kostengünstiger Virtual Reality Headsets zurück zu führen. Oculus Rift trat vor wenigen Jahren einen Siegeszug an, es folgten SAMSUNGs Gear VR oder HTCs Re Vive, um einige VR-Projekte zu nennen. Nun ist die Virtuelle Realität omnipräsent. Zugegebenermaßen wird in diesem Zusammenhang die Virtuelle Realität momentan hauptsächlich mit dem Game-Genre in Verbindung gebracht, jedoch ist es ein Frage der Zeit, bis auch andere Anwendungsfelder - so auch die Medizin - mit preiswerten VR-Lösungen und Headsets ernsthaft bearbeitet werden. Virtuelle Realität hat jedoch schon vor vielen Jahren Einzug in der Medizin erhalten. Rasante Entwicklungen der letzten Jahre in der Gerätetechnologie sowie bei den (Graphik-) Prozessorarchitekturen (GPU) haben zu einer zunehmend technologiebasierten Medizin geführt. Speziell auf dem Gebiet der Chirurgie wurden neue Möglichkeiten und ein Mehrwert gesehen.

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Sourina, Olga; Liu, Yisi; Hou, Xiyuan; Lim, Wei Lun; Müller-Wittig, Wolfgang K.; Wang, Lipo; Konovessis, Dimitrios; Chen, Chun-Hsien; Ang, Wei Tech

Neuroscience Based Design: Fundamentals and Applications

2016

Sourin, Alexei (Ed.) et al.: 2016 International Conference on Cyberworlds : CW 2016. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2016, pp. 250-257

International Conference on Cyberworlds (CW) <2016, Chongqing, China>

Neuroscience-based or neuroscience-informed design is a new application area of Brain-Computer Interaction (BCI). It takes its roots in study of human well-being in architecture, human factors study in engineering and manufacturing including neuroergonomics. In traditional human factors studies and/or well-being study, mental workload, stress, and emotion are obtained through questionnaires that are administered upon completion of some task and/or the whole experiment. Recent advances in BCI research allow for using Electroencephalogram (EEG) based brain state recognition algorithms to assess the interaction between brain and human performance. We propose and develop an EEG-based system CogniMeter to monitor and analyze human factors measurements of newly designed software/hardware systems and/or working places. Machine learning techniques are applied to the EEG data to recognize levels of mental workload, stress and emotions during each task. The EEG is used as a tool to monitor and record the brain states of subjects during human factors study experiments. We describe two applications of CogniMeter system: human performance assessment in maritime simulator and EEG-based human factors evaluation in Air Traffic Control (ATC) workplace. By utilizing the proposed EEG-based system, true understanding of subjects working patterns can be obtained. Based on the analyses of the objective real time EEG-based data together with the subjective feedback from the subjects, we are able to reliably evaluate current systems/hardware and/or working place design and refine new concepts and design of future systems.

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Erdt, Marius; Maroothynaden, Jason; Peng Junming, Jimmy; Müller-Wittig, Wolfgang K.; Gagnon, Paul

Augmented Reality as a Tool to Deliver e-Learning Based Blended Content in and out of the Class-room

2015

Bronstein, Michael (Ed.) et al.: Eurographics 2015. Education Papers. The Eurographics Association, 2015, pp. 39-40

Annual Conference of the European Association for Computer Graphics (Eurographics) <36, 2015, Zürich, Switzerland>

In this paper, we present a mobile Augmented Reality application that can be used for undergraduate anatomical education. It can be used in and out of the classroom. In the classroom, the application can track and augment 3D objects such as a cadaveric solid organ (e.g. heart) specimens as well as 3D plastic anatomical models without the use of observable markers. Out-side the classroom, virtual representations of the hearts were computed and added as an offline version to the application allowing students to self-learn. To allow students to "sense-make" concepts and add additional educational value to offline content, the application can also track 2D content like printed posters. Augmentation in 2D and 3D views via various digital content modalities supports students in learning and "sense-making" anatomical terms and concepts.

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Hou, Xiyuan; Liu, Yisi; Sourina, Olga; Müller-Wittig, Wolfgang K.

CogniMeter: EEG-based Emotion, Mental Workload and Stress Visual Monitoring

2015

Sourin, Alexei (Steering Committee Coordinator) et al.: 2015 International Conference on Cyberworlds : CW 2015. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2015, pp. 153-160

International Conference on Cyberworlds (CW) <14, 2015, Visby, Sweden>

Real-time EEG (Electroencephalogram)-based user's emotion, mental workload and stress monitoring is a new direction in research and development of human-machine interfaces. It has attracted recently more attention from the research community and industry as wireless portable EEG devices became easily available on the market. EEG-based technology has been applied in anesthesiology, psychology, serious games or even in marketing. In this work, we describe available real-time algorithms of emotion recognition, mental workload, and stress recognition from EEG and propose a novel interface CogniMeter for the user's mental state visual monitoring. The system can be used in real time to assess human current emotions, levels of mental workload and stress. Currently, it is applied to monitor the user's emotional state, mental workload and stress in simulation scenarios or used as a tool to assess the subject's mental state in human factor study experiments.

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Ming, Qi; Erdt, Marius; Kan, Chen; Lee, Eugene; Voss, Gerrit; Müller-Wittig, Wolfgang K.

InfoView3D: A Solution Showing Educational Model on Multi-Touch Surfaces

2015

Bronstein, Michael (Ed.) et al.: Eurographics 2015. Education Papers. The Eurographics Association, 2015, pp. 41-42

Annual Conference of the European Association for Computer Graphics (Eurographics) <36, 2015, Zürich, Switzerland>

In this paper, we present a solution for educational presentation which can integrate images, documents, videos, and especially 3D models in a tree based structure. The solution is based on HTML5 and JavaScript, using SVG and X3D techniques and interacting with multi-touch events, therefore supporting multi-touch surfaces that can run a fully-functional browser. In practice, our solution is used for demonstrations both on tablet PCs and a multi-touch video wall.

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Feraco, Antonio; Müller-Wittig, Wolfgang K.

Singapore Policy-Making Processes: The Impact of ICT to Enhance Public Participation and Gather Meaningful Insights

2014

Sonntagbauer, Peter et al.: Handbook of Research on Advanced ICT Integration for Governance and Policy Modeling. Hershey, Pennsylvania: IGI Global, 2014, pp. 389-404

In Singapore, ICT plays a key role as enabling technology for the most of sectors, several initiatives have been launched to gather insights from these large amounts of data and the utilization of visual solutions as a mean to provide useful insights represents the basis for policy makers' decisions. Further to it Singapore is promoting the usage of new channels of communications to optimise processes of e-Participation, to enhance public inputs in governmental activities and other initiatives to gather insights from geo-spatial, behavioural, commercial, scientific data. The following chapter aims to provide an overview about Singapore IT strategies development and the relation between Government and key-stakeholders to define and establish new policies, governance and the framework implemented through the value add provided by IT and Visual solution ad-hoc utilised.

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Xin, Shi-Qing; Wang, Xiaoning; Xia, Jiazhi; Müller-Wittig, Wolfgang K.; Wang, Guo-Jin; He, Ying

Parallel Computing 2D Voronoi Diagrams Using Untransformed Sweepcircles

2013

Computer-Aided Design: CAD, Vol.45 (2013), 2, pp. 483-493

Voronoi diagrams are among the most important data structures in geometric modeling. Among many efficient algorithms for computing 2D Voronoi diagrams, Fortune's sweepline algorithm (Fortune, 1986 [5]) is popular due to its elegance and simplicity. Dehne and Klein (1987) [8] extended sweepline to sweepcircle and suggested computing a type of transformed Voronoi diagram, which is parallel in nature. However, there is no practical implementation of the sweepcircle algorithm due to the difficulty in representing the transformed edges. This paper presents a new algorithm, called untransformed sweepcircle, for constructing Voronoi diagram in R2. Starting with a degenerate circle (of zero radius) centered at an arbitrary location, as the name suggests, our algorithm sweeps the circle by increasing its radius across the plane. At any time during the sweeping process, each site inside the sweep circle defines an ellipse composing of points equidistant from that point and from the sweep circle. The union of all ellipses forms the beach curve-a star shape inside the sweep circle which divides the portion of the plane within which the Voronoi diagram can be completely determined, regardless of what other points might be outside of the sweep circle. As the sweep circle progresses, the intersection of expanding ellipses defines the Voronoi edges. We show that the sweep line algorithm is the degenerate form of the proposed sweep circle algorithm when the circle center is at infinity, and our algorithm has the same time and space complexity as the sweep line algorithm. Our untransformed sweepcircle algorithm is flexible in allowing multiple circles at arbitrary locations to sweep the domain simultaneously. The parallelized implementation is pretty easy without complicated numerical computation; the most complicated case is nothing but an arc-cosine operation. Furthermore, our algorithm supports the additively weighted Voronoi diagrams of which the Voronoi edges are hyperbolic and straight line segments. We demonstrate the efficacy of our parallel sweep circle algorithm using a GPU.

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Chen, Kan; Johan, Henry; Müller-Wittig, Wolfgang K.

Simple and Efficient Example-based Texture Synthesis Using Tiling and Deformation

2013

ACM SIGGRAPH: Proceedings I3D 2013 : ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games. New York: ACM Press, 2013, pp. 145-152

ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games (i3D) <17, 2013, Orlando, FL, USA>

In computer graphics, textures represent the detail appearance of the surface of objects, such as colors and patterns. Example-based texture synthesis is to construct a larger visual pattern from a small example texture image. In this paper, we present a simple and efficient method which can synthesize a large scale texture in real-time based on a given example texture by simply tiling and deforming the example texture. Different from most of the existing techniques, our method does not perform search operation and it can compute texture values at any given points (random access). In addition, our method requires small storage which is only to store one example texture. Our method is suitable for synthesizing irregular and near-stochastic texture. We also propose methods to efficiently synthesize and map 3D solid textures on 3D meshes.

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Zhang, Long; Xia, Jiazhi; Ying, Xiang; He, Ying; Müller-Wittig, Wolfgang K.; Seah, Hock-Soon

Efficient and Robust 3D Line Drawings Using Difference-of-Gaussian

2012

Graphical Models, Vol.74 (2012), 4, pp. 87-98

Line drawings are widely used for sketches, animations, and technical illustrations because they are effective and easy to draw. The existing computer-generated lines, such as suggestive contours, apparent ridges, and demarcating curves, adopt the two-pass framework: in the first pass, certain geometric features or properties are extracted or computed in the object space; then in the second pass, the line drawings are rendered by iterating each polygonal face or edge. It is known these approaches are very sensitive to the mesh quality, and usually require appropriate preprocessing operations (e.g. smoothing, remeshing, etc.) to the input meshes. This paper presents a simple yet robust approach to generate view-dependent line drawings for 3D models. Inspired by the image edge detector, we compute the difference-of-Gaussian of illumination on the 3D model. With moderate assumption, we show all the expensive computations can be done in the pre-computing stage. Our method naturally integrates object- and image-spaces in that we compute the geometric features in the object space and then adopt a simple fragment shader to render the lines in the image space. As a result, our algorithm is more efficient than the existing object-space approaches, since the lines are generated in a single pass without iterating the mesh edges/faces. Furthermore, our method is more flexible and robust than the existing algorithms in that it does not require the preprocessing on the input 3D models. Finally, the difference-of-Gaussian operator can be extended to the anisotropic setting guided by local geometric features. The promising experimental results on a wide range of real-world models demonstrate the effectiveness and robustness of our method.

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Zhang, Long; He, Ying; Seah, Hock-Soon; Müller-Wittig, Wolfgang K.

A Hybrid Object/Image Space Approach for Efficient and Robust Line Drawings

2011

Pan, Zhigeng (Ed.) et al.: ACM Siggraph Asia 2011 Sketches. New York: ACM Press, 2011, 2 p.

Conference on Computer and Exhibition on Computer Graphics and Interactive Techniques in Asia (SIGGRAPH ASIA) <4, 2011, Hong Kong, China>

Line drawings are an effective way to convey shapes in a relatively succinct manner by ignoring the less important or distracting details. In the past decade, many promising computer-generated line drawing algorithms have been proposed, which can be roughly classified into two categories: object-space and image-space.

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Liu, Weiguo; Schmidt, Bertil; Müller-Wittig, Wolfgang K.

CUDA-BLASTP: Accelerating BLASTP on CUDA-Enabled Graphics Hardware

2011

IEEE/ACM Transactions on Computational Biology and Bioinformatics, Vol.8 (2011), 6, pp. 1678-1684

Scanning protein sequence database is an often repeated task in computational biology and bioinformatics. However, scanning large protein databases, such as GenBank, with popular tools such as BLASTP requires long runtimes on sequential architectures. Due to the continuing rapid growth of sequence databases, there is a high demand to accelerate this task. In this paper, we demonstrate how GPUs, powered by the Compute Unified Device Architecture (CUDA), can be used as an efficient computational platform to accelerate the BLASTP algorithm. In order to exploit the GPU's capabilities for accelerating BLASTP, we have used a compressed deterministic finite state automaton for hit detection as well as a hybrid parallelization scheme. Our implementation achieves speedups up to 10.0 on an NVIDIA GeForce GTX 295 GPU compared to the sequential NCBI BLASTP 2.2.22. CUDA-BLASTP source code which is available at https://sites.google.com/site/liuweiguohome/software.

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Ho, Caroline M.L.; Nelson, Mark Evan; Müller-Wittig, Wolfgang K.

Design and Implementation of a Student-Generated Virtual Museum in a Language Curriculum to Enhance Collaborative Multimodal Meaning-Making

2011

Computers & Education, Vol.57 (2011), 1, pp. 1083-1097

This paper reports on a study, MUSE, which involved Secondary (Grade 7) students in designing and constructing a virtual museum. It presents a description and evaluation of the design and implementation of the technologically-mediated intervention within a language curriculum that emphasizes multimodal meaning-making and expression. Participants' gallery artifacts, interviews, reflections and classroom observations indicated signs of an emergent multimodal awareness with a growing sensitivity to semiotic affordances and constraints. Collaborative learning skills acquired and languages learning motivational gains were evident. The investigation identified responsive, adaptive measures in overcoming unanticipated challenges arising from on-the-ground realities and contextual constraints. The study showed the viability, to a certain extent, of innovative technologically-enhanced interventions in reinforcing instructional pedagogy in classroom contexts.

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Liu, Weiguo; Schmidt, Bertil; Liu, Yongchao; Voss, Gerrit; Müller-Wittig, Wolfgang K.

Mapping of BLASTP Algorithm onto GPU Clusters

2011

IEEE Computer Society: International Conference on Parallel and Distributed Systems : ICPADS 2011. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2011, pp. 236-243

International Conference on Parallel and Distributed Systems (ICPADS) <17, 2011, Tainan, Taiwan>

Searching protein sequence database is a fundamental and often repeated task in computational biology and bioinformatics. However, the high computational cost and long runtime of many database scanning algorithms on sequential architectures heavily restrict their applications for large-scale protein databases, such as GenBank. The continuing exponential growth of sequence databases and the high rate of newly generated queries further deteriorate the situation and establish a strong requirement for time-efficient scalable database searching algorithms. In this paper, we demonstrate how GPU clusters, powered by the Compute Unified Device Architecture (CUDA), OpenMP, and MPI parallel programming models can be used as an efficient computational platform to accelerate the popular BLASTP algorithm. Compared to GPU-BLAST 1.0-2.2.24, our implementation achieves speedups up to 1.6 on a single GPU and up to 6.6 on the 6 GPUs of a Tesla S1060 quad- GPU computing system. The source code is available at: http://sites.google.com/site/liuweiguohome/mpicuda-blastp

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Müller-Wittig, Wolfgang K.

Virtual Reality in Medicine

2011

Kramme, Rüdiger (Ed.) et al.: Springer Handbook of Medical Technology. Berlin, Heidelberg, New York: Springer, 2011, pp. 1167-1186

Medicine over the past decades has undergone significant changes. In particular, surgery has become increasingly more technology based due to advances and rapid developments in device technology and computer graphics. Minimally invasive surgery (MIS) has revolutionized surgery introducing optical systems and small surgical instruments. In computer graphics Virtual Reality (VR) allows a more intuitive interaction with three-dimensional (3-D) computer generated environments. Furthermore, Augmented Reality (AR) provides a real-time overlay of reality with digital information. This transformation opens up new opportunities for diagnostics, medical education, preoperative planning and intraoperative support. The traditional see one, do one, teach one educational environment has now changed to simulation-based training where sophisticated surgical procedures can be planned and rehearsed in a safe virtual environment before the patient enters the operating room (OR). In the operating theatre the surgeon's abilities can be enhanced by superimposing computer generated information on the real patient resulting in better navigation and higher precision of the surgical intervention. With the increasing role of quality management and certification in the health care system, medical simulation can lead to improved quality of care and patient outcomes becoming an integral element finally.

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Müller-Wittig, Wolfgang K.

Virtuelle Realität in der Medizin

2011

Kramme, Rüdiger (Ed.): Medizintechnik : Verfahren - Systeme - Informationsverarbeitung. Berlin, Heidelberg, New York: Springer, 2011, pp. 847-858

Die rasanten Entwicklungen, die sich in den letzten 20 Jahren vollzogen haben, haben die Chirurgie maßgeblich verändert, und sie wird unvermeidlich noch größere Änderungen in den nächsten Jahren erfahren. Die Chirurgie wird zunehmend technologiebasiert. In der Computergraphik bilden Techniken der virtuellen Realitat (VR) eine neue Dimension in der Mensch-Maschine-Interaktion. In der Chirurgie hat ein Wechsel des Interaktionsparadigmas durch den Übergang von der offenen zur minimalinvasiven Chirurgie (MIC) stattgefunden.

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Shi, Haixiang; Schmidt, Bertil; Liu, Weiguo; Müller-Wittig, Wolfgang K.

A Parallel Algorithm for Error Correction in High-Throughput Short-Read Data on CUDA-Enabled Graphics Hardware

2010

Journal of Computational Biology [online], Vol.17 (2010), 4, pp. 603-615

Emerging DNA sequencing technologies open up exciting new opportunities for genome sequencing by generating read data with a massive throughput. However, produced reads are significantly shorter and more error-prone compared to the traditional Sanger shotgun sequencing method. This poses challenges for de novo DNA fragment assembly algorithms in terms of both accuracy (to deal with short, error-prone reads) and scalability (to deal with very large input data sets). In this article, we present a scalable parallel algorithm for correcting sequencing errors in high-throughput short-read data so that error-free reads can be available before DNA fragment assembly, which is of high importance to many graph-based short-read assembly tools. The algorithm is based on spectral alignment and uses the Compute Unified Device Architecture (CUDA) programming model. To gain efficiency we are taking advantage of the CUDA texture memory using a space-efficient Bloom filter data structure for spectrum membership queries. We have tested the runtime and accuracy of our algorithm using real and simulated Illumina data for different read lengths, error rates, input sizes, and algorithmic parameters. Using a CUDA-enabled mass-produced GPU (available for less than US$400 at any local computer outlet), this results in speedups of 12-84 times for the parallelized error correction, and speedups of 3-63 times for both sequential preprocessing and parallelized error correction compared to the publicly available Euler-SR program. Our implementation is freely available for download from http:// cuda-ec.sourceforge.net.

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Shi, Haixiang; Schmidt, Bertil; Liu, Weiguo; Müller-Wittig, Wolfgang K.

Quality-Score Guided Error Correction for Short-Read Sequencing Data using CUDA

2010

Procedia Computer Science [online], Vol.1 (2010), 1, pp. 1129-1138

International Conferences on Computational Science (ICCS) <10, 2010, Amsterdam, Netherlands>

Recently introduced new sequencing technologies can produce massive amounts of short-read data. Detection and correction of sequencing errors in this data is an important but time-consuming pre-processing step for de-novo genome assembly. In this paper, we demonstrate how the quality-score value associated with each base-call can be integrated in a CUDA-based parallel error correction algorithm. We show that quality-score guided error correction can improve the assembly accuracy of several datasets from the NCBI SRA (Short-Read Archive) in terms of N50-values as well as runtime. We further propose a number of improvements of to our previously published CUDA-EC algorithm to improve its runtime by a factor of up to 1.88.

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Peng Junming, Jimmy; Müller-Wittig, Wolfgang K.

Understanding Ohm's Law - Enlightenment through Augmented Reality

2010

Cani, Marie-Paule (Ed.) et al.: ACM Siggraph Asia 2010 Sketches. New York: ACM Press, 2010, 2 p.

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH Asia) <3, 2010, Seoul, Korea>

This paper proposes a new interactive environment for learning the basics of electricity in series and parallel circuits using augmented reality (AR). The system allows the student to design and study electric circuits by placing symbolic cards representing resistors on a board. Then this board is overlaid by a 3D virtual circuit with its electrical components. Finally, this virtual circuit is coupled back to reality by lighting up a real bulb with intensity depending on the chosen layout. In addition, the mathematical relationship between current, resistance and voltage (Ohm's law) is presented in an information window.

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Shi, Haixiang; Schmidt, Bertil; Liu, Weiguo; Müller-Wittig, Wolfgang K.

Accelerating Error Correction in High-Throughput Short-Read DNA Sequencing Data with CUDA

2009

IEEE Computer Society: Proceedings of the 23th International Parallel and Distributed Processing Symposium : IPDPS 2009. Los Alamitos, Calif.: IEEE Computer Society, 2009, 8 p.

IEEE International Parallel and Distributed Processing Symposium (IPDPS) <23, 2009, Rome, Italy>

Emerging DNA sequencing technologies open up exciting new opportunities for genome sequencing by generating read data with a massive throughput. However, produced reads are significantly shorter and more error-prone compared to the traditional Sanger shotgun sequencing method. This poses challenges for de-novo DNA fragment assembly algorithms in terms of both accuracy (to deal with short, error-prone reads) and scalability (to deal with very large input data sets). In this paper we present a scalable parallel algorithm for correcting sequencing errors in high-throughput short-read data. It is based on spectral alignment and uses the CUDA programming model. Our computational experiments on a GTX 280 GPU show runtime savings between 10 and 19 times (for different error-rates using simulated datasets as well as real Solexa/Illumina datasets).

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2009

Bullinger, Hans-Jörg (Ed.): Technology Guide : Principles, Applications, Trends. Berlin, Heidelberg, New York: Springer, 2009, pp. 250-255

The rapid development of microprocessors and graphics processing units (GPUs) has had an impact on information and communication technologies (lCT) over recent years. "Shaders" offer real-time visualisation of complex, computer-generated 3D models with photorealistic quality. Shader technology includes hardware and software modules which colour virtual 3D objects and model reflective properties. These developments have laid the foundations for mixed reality systems which enable both immersion into and realtime interaction with the environment. These environments are based on Milgram's mixed reality continuum where reality is a gradated spectrum ranging from real to virtual spaces.

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Zhang, Huiliang; Schmidt, Bertil; Müller-Wittig, Wolfgang K.

Accelerating BLASTP on the Cell Broadband Engine

2008

Chetty, Madhu (Ed.) et al.: Pattern Recognition in Bioinformatics : Third IAPR International Conference, PRIB 2008. Berlin; Heidelberg; New York: Springer, 2008. (Lecture Notes in Bioinformatics (LNBI) 5265), pp. 460-470

IAPR International Conference (PRIB) <3, 2008, Melbourne, Australia>

The enormous growth of biological sequence databases has caused bioinformatics to be rapidly moving towards a data-intensive, computational science. As a result, the computational power needed by bioinformatics applications is growing rapidly as well. The recent emergence of low cost parallel accelerator technologies has made it possible to reduce execution times of many bioinformatics applications. In this paper, we demonstrate how the PlayStation®3, powered by the Cell Broadband Engine, can be used as an efficient computational platform to accelerate the popular BLASTP algorithm.

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Liu, Weiguo; Schmidt, Bertil; Voss, Gerrit; Müller-Wittig, Wolfgang K.

Accelerating Molecular Dynamics Simulations Using Graphics Processing Units with CUDA

2008

Computer Physics Communications, Vol.179 (2008), 9, pp. 634-641

Molecular dynamics is an important computational tool to simulate and understand biochemical processes at the atomic level. However, accurate simulation of processes such as protein folding requires a large number of both atoms and time steps. This in turn leads to huge runtime requirements. Hence, finding fast solutions is of highest importance to research. In this paper we present a new approach to accelerate molecular dynamics simulations with inexpensive commodity graphics hardware. To derive an efficient mapping onto this type of computer architecture, we have used the new Compute Unified Device Architecture programming interface to implement a new parallel algorithm. Our experimental results show that the graphics card based approach allows speedups of up to factor nineteen compared to the corresponding sequential implementation.

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Chen, Chen; Schmidt, Bertil; Liu, Weiguo; Müller-Wittig, Wolfgang K.

GPU-MEME: Using Graphics Hardware to Accelerate Motif Finding in DNA Sequences

2008

Chetty, Madhu (Ed.) et al.: Pattern Recognition in Bioinformatics : Third IAPR International Conference, PRIB 2008. Berlin; Heidelberg; New York: Springer, 2008. (Lecture Notes in Bioinformatics (LNBI) 5265), pp. 448-459

IAPR International Conference (PRIB) <3, 2008, Melbourne, Australia>

Discovery of motifs that are repeated in groups of biological sequences is a major task in bioinformatics. Iterative methods such as expectation maximization (EM) are used as a common approach to find such patterns. However, corresponding algorithms are highly compute-intensive due to the small size and degenerate nature of biological motifs. Runtime requirements are likely to become even more severe due to the rapid growth of available gene transcription data. In this paper we present a novel approach to accelerate motif discovery based on commodity graphics hardware (GPUs). To derive an efficient mapping onto this type of architecture, we have formulated the compute-intensive parts of the popular MEME tool as streaming algorithms. Our experimental results show that a single GPU allows speedups of one order of magnitude with respect to the sequential MEME implementation. Furthermore, parallelization on a GPU-cluster even improves the speedup to two orders of magnitude.

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Müller-Wittig, Wolfgang K.; Voss, Gerrit

Challenges for Modern Scene-Graph Systems

2007

Amicis, Raffaele de (Ed.) et al.: 5th Italian Chapter Conference : Eurographics Italian Chapter Proceedings. Aire-la-Ville: Eurographics, 2007, pp. 45-49

Eurographics Italian Chapter Conference <5, 2007, Trento, Italy>

Current scenegraph systems, especially systems used to build general purpose virtual reality systems, are trailing game engines and similar specialized systems in terms of the adaption of new renderingmethods like the different real-time shadow algorithms. This paper analysis the fundamental OpenGL state abstraction layers present in current scenegraph systems with respect to their influence on the adaption of new and complex rendering algorithms.

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Müller-Wittig, Wolfgang K.; Zhu, Chao; Voss, Gerrit

Cultural Heritage as Digital Experience: A Singaporean Perspective

2007

HCI International 2007. Proceedings and Posters [DVD-ROM] : With 8 further Associated Conferences. Berlin, Heidelberg, New York: Springer, 2007. (Lecture Notes in Computer Science (LNCS)), LNCS 4563, pp.680-688

International Conference on Virtual Reality (ICVR) <2, 2007, Beijing, China>

Interactive 3D computer graphics technology is now extremely popular, seen in the increasing interest in and use of 3D digitization of cultural heritage contents. This paper introduces a digital interactive cultural heritage system which embeds Virtual-Reality (VR) technology within the Peranakan culture, the Peranakan culture being a Singaporean unique ethnic culture. A prototype has undergone the full developmental process of being implemented, tested, and evaluated. This paper will also discuss the results of the usability test.

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Liu, Weiguo; Müller-Wittig, Wolfgang K.; Schmidt, Bertil

Performance Analysis of General-Purpose Computation on Commodity Graphics Hardware: A Case Study Using Bioinformatics

2007

Journal of VLSI Signal Processing-Systems for Signal, Image, and Video Technology, Vol.48 (2007), 3, pp. 209-221

Using modern graphics processing units for no-graphics high performance computing is motivated by their enhanced programmability, attractive cost/performance ratio and incredible growth in speed. Although the pipeline of a modern graphics processing unit (GPU) permits high throughput and more concurrency, they bring more complexities in analyzing the performance of GPU-based applications. In this paper, we identify factors that determine performance of GPU-based applications. We then classify them into three categories: data-linear, data-constant and computation-dependent. According to the characteristics of these factors, we propose a performance model for each factor. These models are then used to predict the performance of bio-sequence database scanning application on GPUs. Theoretical analyses and measurements show that our models can achieve precise performance predictions.

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Liu, Weiguo; Müller-Wittig, Wolfgang K.; Schmidt, Bertil

Performance Predictions for General-Purpose Computation on GPUs

2007

Li, Jiandong (Ed.) et al.: 2007 International Conference on Parallel Processing [CD-ROM] : ICPP 2007. Los Alamitos, Calif.: IEEE Computer Society, 2007, 8 p.

International Conference on Parallel Processing (ICPP) <36, 2007, Xi'an, China>

Using modern graphics processing units for no-graphics high performance computing is motivated by their enhanced programmability, attractive price/performance ratio and incredible growth in speed. Although the pipeline of a modern graphics processing unit (GPU) permits high throughput and more concurrency, they bring more complexities in analyzing the performance of GPU-based applications. In this paper, we identify factors that determine performance of GPU-based applications. We then classify them into three categories: data-linear, data-constant and computation-dependent. According to the characteristics of these factors, we propose a performance model for each factor. These models are then used to predict the performance of bio-sequence database scanning application on GPUs. Theoretical analyses and measurements show that our models can achieve precise performance predictions.

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Chen, Chen; Singh, Aarti; Liu, Weiguo; Müller-Wittig, Wolfgang K.; Mitchell, W.; Schmidt, Bertil

Phenotype Genotype Exploration on a Desktop GPU Grid

2007

Yan, Lee Hing (Ed.) et al.: GCA 2007 : Proceedings of the 3rd International Workshop on Grid Computing and Applications. Singapore; New Jersey: World Scientific, 2007, pp. 154-166

International Workshop on Grid Computing and Applications (GCA) <3, 2007, Singapore>

Comparative genomics provides a powerful tool for studying evolutionary changes among organisms. We have designed a new tool, called Phenotype Genotype Explorer to nominate candidate genes responsible for a given phenotype. There are huge datasets involved which makes this approach impractical on traditional computer architectures leading to prohibitively long runtimes. In this paper, we present a computational architecture based on a desktop grid environment and commodity graphics hardware to significantly accelerate the comparative genomics application. We present the deployment and evaluation of this approach on our grid testbed for the comparison of microbial genomes.

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Liu, Weiguo; Schmidt, Bertil; Voss, Gerrit; Müller-Wittig, Wolfgang K.

Streaming Algorithms for Biological Sequence Alignment on GPUs

2007

IEEE Transactions on Parallel and Distributed Systems, Vol.18 (2007), 9, pp. 1270-1281

Sequence alignment is a common and often repeated task in molecular biology. Typical alignment operations consist of finding similarities between a pair of sequences (pairwise sequence alignment) or a family of sequences (multiple sequence alignment). The need for speeding up this treatment comes from the rapid growth rate of biological sequence databases: Every year their size increases by a factor of 1.5 to 2. In this paper, we present a new approach to high-performance biological sequence alignment based on commodity PC graphics hardware. Using modern graphics processing units (GPUs) for high-performance computing is facilitated by their enhanced programmability and motivated by their attractive price/performance ratio and incredible growth in speed. To derive an efficient mapping onto this type of architecture, we have reformulated dynamic-programming-based alignment algorithms as streaming algorithms in terms of computer graphics primitives. Our experimental results show that the GPU-based approach allows speedups of more than one order of magnitude with respect to optimized CPU implementations.

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Müller-Wittig, Wolfgang K.

Virtuelle Realität in der Medizin

2007

Kramme, Rüdiger (Ed.): Medizintechnik : Verfahren - Systeme - Informationsverarbeitung. Berlin, Heidelberg, New York: Springer, 2007, pp. 791-802

In der Computergraphik bilden Techniken der virtuellen Realität (VR) eine neue Dimension in der Mensch- Maschine-Interaktion. VR ermöglicht eine intuitive Interaktion mit dem Computer und eine immersive, realistische Darstellung von dreidimensionalen computergenerierten Welten unter Verwendung neuartiger Ein- und Ausgabegeräte. Auf diese Weise können Vorgange so realistisch simuliert werden, dass der Benutzer das Gefühl hat, er interagiert in der realen Welt (Encarnacao et al. 1994).

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Liu, Weiguo; Schmidt, Bertil; Voss, Gerrit; Schröder, Andre; Müller-Wittig, Wolfgang K.

Bio-Sequence Database Scanning on a GPU

2006

IEEE Computer Society: Proceedings of the 20th International Parallel and Distributed Processing Symposium : IPDPS 2006. Los Alamitos, Calif.: IEEE Computer Society, 2006, 8 p.

IEEE International Parallel and Distributed Processing Symposium (IPDPS) <20, 2006, Rhodes Island, Greece>

Protein sequences with unknown functionality are often compared to a set of known sequences to detect functional similarities. Efficient dynamic programming algorithms exist for this problem, however current solutions still require significant scan times. These scan time requirements are likely to become even more severe due to the rapid growth in the size of these databases. In this paper, we present a new approach to bio-sequence database scanning using computer graphics hardware to gain high performance at low cost. To derive an efficient mapping onto this type of architecture, we have reformulated the Smith- Waterman dynamic programming algorithm in terms of computer graphics primitives. Our OpenGL implementation achieves a speedup of approximately sixteen on a high-end graphics card over available straightforward and optimized CPU Smith-Waterman implementations.

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Liu, Weiguo; Schmidt, Bertil; Voss, Gerrit; Müller-Wittig, Wolfgang K.

GPU-ClustalW: Using Graphics Hardware to Accelerate Multiple Sequence Alignment

2006

Robert, Yves (Ed.) et al.: High Performance Computing : HiPC 2006. Berlin, Heidelberg, New York: Springer, 2006. (Lecture Notes in Computer Science (LNCS) 4297), pp. 363-374

International Conference on High-Performance Computing (HiPC) <13, 2006, Bangalore, India>

Molecular Biologists frequently compute multiple sequence alignments (MSAs) to identify similar regions in protein families. However, aligning hundreds of sequences by popular MSA tools such as ClustalW requires several hours on sequential computers. Due to the rapid growth of biological sequence databases biologists have to compute MSAs in a far shorter time. In this paper we present a new approach to reduce this runtime using graphics processing units (GPUs). To derive an effient mapping onto this type of architecture, we have reformulated the computationally most expensive part of ClustalW in terms of computer graphics primitives. This results in a high-speed implementation with significant runtime savings on a commodity graphics card.

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Voss, Gerrit; Müller-Wittig, Wolfgang K.; Schmidt, Bertil; Schröder, Andre

Using Graphics Hardware to Accelerate Biological Sequence Database Scanning

2005

TENCON 2005 : IEEE Region 10 Conference [CD-ROM]. New York: The Institute of Electrical and Electronics Engineers (IEEE), 2005, 6 p.

IEEE International Region 10 Conferences (TENCON) <2005, Melbourne, Australia>

Sequence alignment is a common and often repeated task in molecular biology. The need for speeding up this treatment comes from the rapid growth rate of biological sequence databases. In this paper we present a new approach to high performance biological sequence database scanning on graphics processing units. Using modern graphics processing units for high performance computing is facilitated by their enhanced programmability and motivated by their attractive price/performance ratio and incredible growth in speed. To derive an efficient mapping onto this type of architecture, we have reformulated the Smith-Waterman dynamic programming algorithm in terms of computer graphics primitives. This results in an implementation with significant runtime savings on two standard off-the-shelf computer graphics cards. To our knowledge this is the first reported mapping of biological sequence alignment onto a graphics processing unit.

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Song, Meehae; Elias, Thomas; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Using the Chinese Calligraphy Brush as a Tangible User Interface Tool in Virtual Heritage Scenarios

2005

Computers & Graphics, Vol.29 (2005), 2, pp. 41-48

This paper first presents a virtual heritage scenario and then discusses the implementation of using a Chinese Calligraphy brush as a tangible user interface tool to fit the context of this scenario. It then closely looks at how the brush has been implemented with basic and extended functionalities to the man-machine interface of the presented virtual environment.

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Quick, Jochen; Zhu, Chao; Wang, Haibin; Song, Meehae; Müller-Wittig, Wolfgang K.

Building a Virtual Factory

2004

ACM SIGGRAPH: Computer Graphics and Interactive Techniques in Australasia and South East Asia. Proceedings : 2nd Computer Graphics and Interactive Techniques in Australasia and South East Asia. New York: ACM, 2004, pp. 199-203

International Conference on Computer Graphics and Interactive Techniques in Australasia and South East Asia (GRAPHITE) <2, 2004, Singapore>

In this paper, we describe a visualisation system which helps simulation experts transform discrete simulation models and results into animated scenes in a virtual environment. The system aims to significantly reduce production costs and error sources during the generation process of visualisations. The means to achieve these goals are the development of a framework for the translation of simulation results into animations, reuse of animation elements, and the implementation of customization tools for animation elements and their behaviour. By utilizing advanced visualisation techniques, the system is also capable of directing the focus of the observer to interesting events, objects and timeframes.

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Song, Meehae; Elias, Thomas; Martinovic, Ivan; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Digital Heritage Applications as an Edutainment Tool

2004

Encarnação, José L. (Honorary Chair) et al.: ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications in Industry. Proceedings : ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications in Industry. New York: ACM, 2004, pp. 163-167

ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications in Industry (VRCAI) <1, 2004, Singapore>

With the fast-growing technological advancements in Virtual Reality (VR) technology and easier access to more affordable computer graphics hardware, it has become possible to create a diverse range of VR applications that are not only geared towards scientific research and medical training applications but also for "edutainment" purposes for the general public. "Edutainment" is an upcoming field that combines education with entertainment aspects thus enhancing the learning environment to be much more engaging and fun-filled. In this paper, we describe a project on a Digital Heritage application aimed to serve as an edutainment tool. The visitors are able to virtually "enter and explore" the reconstructed heritage environment and learn more on the presented content through virtual experiences. We have incorporated a Virtual Tour Guide that presents the cultural and historical content through nonlinear digital storytelling techniques for the dynamic content creation to fit the changing profiles and needs of the visiting audience.

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Kehrer, Bernd; Unbescheiden, Matthias; Marcos, Adérito; Encarnação, L. Miguel; Posada, Jorge; Amicis, Raffaele de; Chan, Tony K.Y.; Müller-Wittig, Wolfgang K.; Kim, Won; Alves dos Santos, Luiz M.

The Colourful World of Computer-Generated Images, Visual Interaction and Visual Communication: Computer Graphics in Practice

2004

Darmstadt : Europäischer Wirtschafts Verlag GmbH, 2004

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Encarnação, José L.; Yue, Chee Yoon; Shi, Jiaoying; Müller-Wittig, Wolfgang K.

VRCAI 2004. Proceedings: ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications in Industry

2004

New York : ACM, 2004

ACM SIGGRAPH International Conference on Virtual Reality Continuum and its Applications in Industry (VRCAI) <1, 2004, Singapore>

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Bockholt, Ulrich; Bisler, Alexander; Becker, Mario; Müller-Wittig, Wolfgang K.; Voss, Gerrit

Augmented Reality for Enhancement of Endoscopic Interventions

2003

Chen, Jim (Ed.) et al.: IEEE Virtual Reality 2003 Conference. Proceedings. Los Alamitos, Calif.: IEEE Computer Society, 2003, pp. 97-101

IEEE Virtual Reality (VR) <10, 2003, Los Angeles, CA, USA>

Computer assisted operation planning systems win more and more recognition in the field of surgery. These systems offer new possibilities to prepare an intervention with the goal to shorten the expansive time in the operation room required for the intervention. The safest and most effective surgical approach should be selected. But often, it is difficult to transfer the output of the planning system to the intra-operative situation and so to consider the planning results in the real intervention. At the Fraunhofer Institute for Computer Graphics (IGD) in Darmstadt and the Centre for Advanced Media Technology (CAMTech) in Singapore, methods are developed to bridge the gap between the external planning session and the intra-operative case: Augmented Reality (AR) techniques are used to overlap preoperative scanned image data as well as results of the planning session to the operation field.

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Turban, Georg; Müller-Wittig, Wolfgang K. (Betreuer); Bockholt, Ulrich (Betreuer)

Development of a Robust Registration Method for Computer Assisted Surgery

2003

Darmstadt, TU, Diplomarbeit, 2003

Current developments in surgery and computer science expose many new technologies and techniques. In the context of minimal invasive surgery, the surgeon is using very small instruments, which are inserted into patient's body through ports. The disadvantage of new surgical approaches like minimal invasive techniques is the more difficult intraoperative orientation for the surgeon, based on intraoperative sensors that deliver only a small part of the intraoperative situation. To assist the surgeon also preoperative data will be acquired. Those data can be used in combination with techniques of augmented reality to enhance the field of view of the surgeon. Registration aims to close the gap between the preoperative operating planning scenario and the intraoperative support by calculating the transformation that maps one data set onto the corresponding other. In the underlying medical scenario, the developed registration algorithm calculates the transformation that maps preoperative data onto intraoperative data. The main idea is not to calculate the transformation in a traditional way by building point correspondences on both data sets based on minimal distances, like the Iterative Closest Point-algorithm. The developed algorithm instead characterizes preoperative and intraoperative surface data to build the desired correspondences between both data sets. Those characteristics can be created for vertices for example and encodes the local neighborhood around such vertices. The integration of additional information like directed characteristics or histological information is elementary and was implemented to enhance the accuracy and performance of the algorithm.

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Martinovic, Ivan; Grimm, Matthias (Betreuer); Müller-Wittig, Wolfgang K. (Betreuer)

Informationsselektion unter Berücksichtigung der aktuellen Situation und persönlicher Interessen des Benutzers

2003

Darmstadt, TU, Diplomarbeit, 2003

This thesis was made at Nanyang University in Singapore as a part of the Digital Heritage project of the Centre for Advanced Media Technology (CAMTech). The idea of the Digital Heritage project is to use Virtual Reality Technology for recreating cultural heritage in a new way that includes modeling Virtual Guide and all information of cultural heritage as a learning environment. The visitor is a learner and the visit is a learning process where a variety of factors influence visitor's virtual environment experience. To be able to help him to easier follow his interest, the user oriented approach in virtual environment is needed. The new idea of assisting the user by providing him the appropriate context dependent information and using his feedback to refine and improve the environment are the main topic of this thesis. The first part of this work, gives an introduction from psychological point of view by examining the user in the role of the visitor. The wide research field of museum experience is used to identify factors important in his visiting session. The concept of this thesis describes the new virtual environment and idea to assist the user in his learning process through encouraging curiosity and active participation. The associations to the real-world analogies are helping the user to understand the knowledge as whole and not only its isolated parts. As a result, the new virtual environment is implemented with the Peranakan culture as content of the virtual environment.

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Song, Meehae; Elias, Thomas; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Interacting with the Virtually Recreated Peranakans

2003

ACM SIGGRAPH: Computer Graphics and Interactive Techniques in Australasia and South East Asia. Proceedings. New York: ACM Press, 2003, pp. 223-228

International Conference on Computer Graphics and Interactive Techniques in Australasia and South East Asia (GRAPHITE) <1, 2003, Melbourne, Australia>

Virtual Reality (VR) technology opens up many new possibilities. One of the new and upcoming areas this VR technology is rapidly being used for is in the Digital Heritage domain. With the abundant content and the need for preservation and conservation for cultural heritage, there has been an explosion of Digital Heritage projects worldwide. VR technology provides an important educational tool to recreate the cultural heritage content in an immersive high-quality 3D environment for the users to enter and experience the culture in real-time. Intuitive interaction techniques providing users other tools as an alternative to the conventional mouse and keyboard input also add to enhanced educational value. Here, we present a Digital Heritage project focusing on the Singapore region. We have selected the Peranakans and their Culture as the main topic for reconstruction using the VR technology. Innovative interaction techniques specific to the selected Digital Heritage content is also under development. This paper outlines the motivation, early developments, and implementation currently in progress.

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Song, Meehae; Elias, Thomas; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Novel Interaction Techniques for Virtual Heritage Applications Using Chinese Calligraphy Brush and Virtual Avatar

2003

Jacko, Julie A. (Ed.) et al.: HCI International 2003. Proceedings of the 10th International Conference on Human-Computer Interaction. Volume 2 : Theory and Practice (Part II). Mahwah, New Jersey: Lawrence Erlbaum, 2003, pp. 776-780

International Conference on Human-Computer Interaction (HCII) <10, 2003, Crete, Greece>

In this paper, we present a digital heritage project incorporating novel interaction techniques in an immersive virtual heritage application. Virtual Reality (VR) technology enables us to digitally recreate immersive and interactive cultural heritage sites that no longer exist or are inaccessible. It is an excellent educational tool providing for a "hands-on" application suitable for a wide range of audiences. Here we present the development and implementation of the virtual heritage application with early results and future work and specifically focus on the two interaction techniques -- the Virtual Tour Guide and the Chinese calligraphy brush.

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Song, Meehae; Elias, Thomas; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Using Virtual Reality to bring Singaporean Heritage to Life

2003

Computer Graphics Society (CGS): Computer Graphics International 2003. Proceedings : CGI 2003. Los Alamitos, CA: IEEE Computer Society Press, 2003, pp. 216-219

Computer Graphics International (CGI) <21, 2003, Tokyo, Japan>

Rapid advances in the field of Virtual Reality (VR) technology has opened up many new areas for research and development. One of the recent important research fields that has emerged is in the field of Digital Heritage. VR technology is an important educational tool that provides immersive and interactive qualities to the cultural heritage content thus enabling us to accurately represent digital reconstructions of heritage sites that are no longer in existence or are inaccessible. In this paper we present our project on the Digital Heritage scenario focusing on cultural heritage content specific to the Singapore region. Innovative interaction techniques specific to the selected Digital Heritage content will also be presented. This paper outlines the motivation, early developments, and implementation currently in progress.

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Zhong, Yongmin; Müller-Wittig, Wolfgang K.; Ma, Weiyin

A Constraint Manager for Intuitive and Precise Solid Modelling in a Virtual Reality Environment

2002

China Society of Image and Graphics: International Conference on Virtual Reality and its Application in Industry 2002 (VRAI). Proceedings, pp.354-361

International Conference on Virtual Reality and its Application in Industry (VRAI) <3, 2002, Hangzhou, China>

The absence of efficient constraint management facilities when interacting with virtual objects is one of the major limitations of current virtual reality systems for CAD applications. Without constraint management facilities, it is difficult to perform precise interactions with today's 3D input devices and precise solid modelling in the VR environments cannot be ensured. In this paper, a constraint manager is presented for intuitive and precise solid modelling in the VR environment. This constraint manager generates constraint-based 3D direct manipulations for precise solid modelling through incorporating constraints into the VR environment. Constraint-based manipulations are realized by allowable motions for precise 3D interactions in the VR environment. The allowable motions are represented as a mathematical matrix for conveniently deriving allowable motions from constraints. A procedure-based degree-of-freedom incorporation solver for solving 3D constraints is presented for deriving th allowable motions. A rule-based constraint recognition engine is developed for implicitly incorporating constraints into the VR environment.

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Zhong, Yongmin; Müller-Wittig, Wolfgang K.

A Hierarchically Structured Constraint-based Data Model for Solid Modelling in a Virtual Reality Environment

2002

Peng, Shietung (Ed.) et al.: First International Symposium on Cyber Worlds. Proceedings 2002. Los Alamitos, Calif.: IEEE Computer Society, 2002, pp. 537-544

International Symposium on Cyber Worlds (CW) <1, 2002, Tokyo, Japan>

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Zhong, Yongmin; Müller-Wittig, Wolfgang K.; Ma, Weiyin

A Model Representation for Solid Modelling in A Virtual Reality Environment

2002

Institute of Electrical and Electronics Engineers (IEEE): International Conference on Shape Modeling and Applications 2002. Proceedings. Los Alamitos: IEEE Computer Society Press, 2002, pp. 183-190

International Conference on Shape Modeling and Applications (SMI) <4, 2002, Banff, Canada>

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Müller-Wittig, Wolfgang K.; Bockholt, Ulrich; Voss, Gerrit; Börner, Martin

A New Approach to Combine Visualization and Simulation for Preoperative Planning of Pedicle Screw Insertion

2002

The International Society for Computer Assisted Orthopaedic Surgery: Computer Assisted Orthopaedic Surgery. Proceedings 2002, pp. 53-55

Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery (CAOS) <2, 2002, Santa Fe, NM, USA>

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Müller-Wittig, Wolfgang K.; Becker, Mario; Bockholt, Ulrich; Voss, Gerrit

Advanced Simulation Environment for Minimally Invasive Procedures in Gynecology

2002

Mills, John (Ed.): ITEC 2002. Europe's Training, Education and Simulation Conference Proceedings. CD-ROM. Lille, 2002, 4 p.

International Training and Education Conference & Exhibition (ITEC) <13, 2002, Lille, France>

Rapid development of medical field, expanding knowledge base and new technologies require continuing medical education to achieve life long learning and to keep the surgeons up to date. Consequently, specific training is necessary to guarantee qualification of the surgeons. To overcome the current drawbacks of traditional training systems (on-the-job training, plastic models etc.) for laparoscopy/hysteroscopy an intelligent adaptable training environment has been realized using Virtual Reality (VR), Multimedia (MM) technology, and Intelligent Tutoring Systems (ITS).

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Müller-Wittig, Wolfgang K.; Becker, Mario; Elias, Thomas; Bockholt, Ulrich; Voss, Gerrit

Advanced Training Environment for Gynecologic Endoscopy

2002

Lemke, Heinz U. (Ed.) et al.: Computer Assisted Radiology and Surgery 2002. Proceedings. Berlin, Heidelberg, New York: Springer, 2002, pp. 107-112

Computer Assisted Radiology and Surgery (CARS) <16, 2002, Paris, France>

Rapid development of medical field, expanding knowledge base and new technologies require continuing medical education to achieve life long learning and to keep the surgeons up to date. Consequently, specific training is necessary to guarantee qualification of the surgeons. To overcome the current drawbacks of traditional training systems (on - the - job training, plastic models etc.) for labaroscopy / hysteroscopy an intelligent adaptable training environment has been realized using Virtual Reality (VR), Multimedia (MM) technology, and Intelligent Tutoring Systems (ITS).

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Zhong, Yongmin; Müller-Wittig, Wolfgang K.

Incorporating Constrains into a Virtual Reality Environment for Intuitive and Precise Solid Modeling

2002

Institute of Electrical and Electronics Engineers (IEEE): Sixth IEEE International Conference on Information Visualisation 2002. Proceedings. Los Alamitos, Calif.: IEEE Computer Society, 2002, pp. 389-398

IEEE International Conference on Information Visualization (IV) <6, 2002, London, UK>

The absence of constraints is one of the major limitations in current Virtual Reality (VR) environments. Without constraints, it is difficult to perform precise 3D interactive manipulations in VR environments and precise solid modelling in VR environments cannot be guaranteed. In this paper, constraints are incorporated into the VR environment for intuitive and precise solid modelling. A hierarchically structured constraint-based data model is developed to support solid modelling in the VR environment. Solid modelling in the VR environment is precisely performed in an intuitive manner through constraint-based manipulations. Constraint-based manipulations are accompanied with automatic constraint recognition and precise constraint satisfaction to establish the hierarchically structured constraint-based data model and are realized by allowable motions for precise 3D interactions in the VR environment. The allowable motions are represented as a mathematical matrix for conveniently deriving allowable motions from constraints. A procedure-based degree-of-freedom incorporation approach for 3D constraint solving is presented for deriving the allowable motions. A rulebased constraint recognition engine is developed for both constraint-based manipulations and implicitly incorporating constraints into the VR environment. A prototype system has been implemented for precise solid modelling in an intuitive manner through constraintbased manipulations in the VR environment.

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Wang, Haibin; Müller-Wittig, Wolfgang K.; Jegathese, Reginald; Song, Meehae; Quick, Jochen; Zhong, Yongmin

Integrated Virtual Factory and Logistics for Electronics Industry

2002

China Society of Image and Graphics: International Conference on Virtual Reality and its Application in Industry 2002 (VRAI). Proceedings, pp. 315-318

International Conference on Virtual Reality and its Application in Industry (VRAI) <3, 2002, Hangzhou, China>

Funded in Singapore National Science and Technology Board (NSTB), CAMTech is collaborating with a Singaporean research institute and two industry partners with the objective to improve electronics assembly processes. The goal of this project is to visualise the behaviour of an electronics assembly industry by simulating, visualising the discrete events of the entire manufacturing processes and observing the flow of materials, size of buffers, and line balancing. The traditional scenario - from the customer placing order for a product to delivery - goes through various phases including manufacturing the product. Several major electronics manufacturing stages can be addressed: fabrication, assembly, testing, and packing. Each of these stages accounts for set up, process, failure, and wait time periods. A delay in one process will accumulate over to the future delays. To simulate the discrete events a general-purpose simulation system has been employed. For modelling and visualisation CASUS ( Computer Animation of Simulation Traces) system has been used developed by Fraunhofer Institute for Computer Graphics (IGD) This work focuses on the prototype interface between simulation trace file and CASUS animation scripts. The final system provides a 3D visualisation of electronics assembly processes based on event-oriented simulator data.

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Müller-Wittig, Wolfgang K.; Mlynski, Gunter; Weinhold, Ivo; Bockholt, Ulrich; Voss, Gerrit

Nasal Airflow Diagnosis - Comparison of Experimental Studies and Computer Simulations

2002

Westwood, James D. (Ed.): Medicine Meets Virtual Reality 2002. Proceedings : Digital Upgrades: Applying Moore's Law to Health. Amsterdam: IOS Press; Ohmsha, 2002. (Studies in Health Technology and Informatics 85), pp. 311-317

Medicine Meets Virtual Reality (MMVR) <10, 2002, Newport Beach, CA, USA>

The lack of situed diagnostic tools providing insight into patient specific flow characteristics of the nasal airflow is one of the main problems in functional diagnosis. Diagnostics methods currently used do not provide the necessary information for flow analysis. But the flow distribution is essential for a physiological repiration, in particular for cleaning moistening and tempering of the inhaled air as well as for the olfactory function of the nose. To overcome this current situation a cooperation project of the ENT surgeons and computer graphic engineers was established to develop the computer assisted planning system STAN (Simulation Tool for Airflow in the human Nose) combining Computer Fluid Dynamics (CFD) with advanced Computer Graphic Technology. The idea of the STAN system is to perform patient specific airflow simulations in the patient's nasal cavities. Therefore a geometrical model of the nasal airways is derived form the patient's tomography scans. A discretization of the surrounded flow volume is made by a computational grid. To establish the flow simulation Finite Element Methods are performed on the grid. A tailored visualization is offered to the surgeon that overlaps the flow pattern to the patient's tomography data shown in the coronal sagittal and transversal plane. The surgeon can not only analyze the patient's current respiration situation he has also the possibility to describe the planned surgical intervention. The goal is to simulate the flow distribution that can be expected after the surgical intervention and to offer a possibility to validate various surgical strategies. To verify the simulation results experimental investigation and measurements are made in nasal models. Silicon Models of patient's nose channels are made to analyze flow characteristics The CT or MR scans of the same patients are used as input data for the simulation. The experimental outcome is compared to the simulation results to validate this diagnostic approach.

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Song, Meehae; Müller-Wittig, Wolfgang K.; Chan, Tony K.Y.

Reconstructing Peranakan Identities through Digital Heritage

2002

International Society on Virtual Systems and MultiMedia: International Conference on Virtual Systems and MultiMedia. VSMM 2002. Proceedings

International Conference on Virtual Systems and MultiMedia (VSMM) <8, 2002, Gyeonju, Korea>

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Bockholt, Ulrich; Mlynski, Gunter; Weinhold, Ivo; Müller-Wittig, Wolfgang K.; Voss, Gerrit

Simulation of the Nasal Airflow - Generation and Evaluation of a Patient Specific Flow

2002

Hutten, Helmut (Ed.) et al.: Second European Medical and Biological Engineering Conference. Proceedings Vol. 2 : Advancement of Medicine and Health Care through Technology - the Challenge to Biomedical Engineering in Europe. Graz: Verlag der Technischen Universität, 2002, pp. 1170-1171

European Medical and Biological Engineering Conference (EMBEC) <2, 2002, Vienna, Austria>

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Zhong, Yongmin; Müller-Wittig, Wolfgang K.

Solid Modelling through Constraint-Based Manipulations in a Virtual Reality Environment

2002

The American Society of Mechanical Engineers (ASME): 2002 ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference.. New York: The American Society of Mechanical Engineers, 2002

ASME Design Engineering Technical Conferences & Computers and Information in Engineering Conference (DETC) <2002, Montreal, Canada>

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Müller-Wittig, Wolfgang K.; Jegathese, Reginald; Song, Meehae; Quick, Jochen; Wang, Haibin; Zhong, Yongmin

Virtual Factory - Highly Interactive Visualisation for Manufacturing

2002

Yücesan, Enver (Ed.) et al.: Proceedings of the 2002 Winter Simulation Conference. New York: IEEE, Inc., 2002, pp. 1061-1064

Winter Simulation Conference (WSC) <2002, San Diego, CA, USA >

Funded by the Agency for Science, Technology and Research, A*STAR Singapore, CAMTech is collaborating with a Singaporean research institute and two industry partners with the objective to improve electronics assembly processes. The goal of this project is to visualise the behaviour of an electronics assembly industry based on discrete events simulation. The traditional scenario - from the customer placing order for a product to delivery - goes through various phases including manufacturing the product. Several major electronics manufacturing stages can be addressed: fabrication, assembly, testing, and packing. Each of these stages accounts for set up, process, failure, and wait time periods. A delay in one process will accumulate over to the future delays. To simulate the discrete events a general-purpose simulation system has been employed. For modelling and visualisation CASUS (Computer Animation of Simulation Traces) system has been used and refined developed by Fraunhofer Institute for Computer Graphics (Fraunhofer-IGD).

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Bockholt, Ulrich; Müller-Wittig, Wolfgang K.; Los Arcos, José Luis; Oppelt, Peter; Stähler, Jan; Voss, Gerrit

Enhanced Training Environment for Minimally Invasive Surgery

2001

Institute of Electrical and Electronics Engineers (IEEE): Proceedings of the 10th IEEE International Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises. Los Alamitos, Calif.: IEEE Computer Society, 2001, pp. 269-272

IEEE International Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises (WET ICE) <10, 2001, Cambridge, MA, USA>

Rapid development of medical field, expanding knowledge base and new technologies require continuing medical education to achieve life long learning and to keep the surgeons up to date. Consequently, specific training is necessary to guarantee qualification of the surgeons. To overcome the current drawbacks of traditional training systems (on-the-job training, plastic models etc.) for laparoscopy/hysteroscopy an intelligent adaptable training environment has been realised using Virtual Reality (VR), Multimedia (MM) technology, ans Intelligent Tutoring Systems (ITS)

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Voss, Gerrit; Bisler, Alexander; Bockholt, Ulrich; Müller-Wittig, Wolfgang K.; Schäffer, Albert

ICAPS - An Integrative Computer-Assisted Planning System for Pedicle Screw Insertion

2001

Westwood, James D. (Ed.): Medicine Meets Virtual Reality 2001. Proceedings : Outer Space, Inner Space, Virtual Space. Amsterdam: IOS Press; Ohmsha, 2001. (Studies in Health Technology and Informatics 81), pp. 561-563

Medicine Meets Virtual Reality (MMVR) <9, 2001, Newport Beach, CA, USA>

Robot Assisted Surgery (RAS) Systems win more and more recognition in the field of orthopaedics. Especially in Hip Surgery RAS has proved to be suited for application in medical routine. Often Robot Assisted Surgery Systems consist of a planning- and an interoperative component. According to specifications done with the planning software the tools are driven. Benefits of the robot assisted surgery should be higher precision and a better surgical outcome. In the co-operation project of several Fraunhofer Institutes "RoMed" (Robots and Manipulators for Medical Application) an exemplary application of robot aided spine surgery is developed. The planning software used in this context is proposed in the remaining article.

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Müller-Wittig, Wolfgang K.; Bockholt, Ulrich; Schäffer, Albert; Voss, Gerrit; Haberland, N.; Börner, Martin

Integrative Preoperative Planning for Pedicle Screw Inseration

2001

The International Society for Computer Assisted Orthopaedic Surgery: Computer Assisted Orthopaedic Surgery. Proceedings 2001

Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery (CAOS) <2001, USA>

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Müller-Wittig, Wolfgang K.; Encarnação, José L. (Betreuer); Börner, Martin (Betreuer)

Kopplung von Objektverhalten anatomischer Strukturen mit haptischen Displays und dazugehörige Interaktionsmöglichkeiten

2001

Stuttgart : Fraunhofer IRB Verlag, 2001

Darmstadt, TU, Diss., 2001

Zwei wesentliche Entwicklungen, die sich auf unterschiedlichen Gebieten - der Computergraphik und der Chirurgie - vollzogen haben, haben diese Arbeit geprägt. In der Computergraphik bilden Techniken der Virtuellen Realität (VR) eine neue Dimension in der Mensch-Maschine-Interaktion. In der Chirurgie hat ein Wechsel des Interaktionsparadigmas durch den Übergang von der offenen zur minimal invasiven Chirurgie stattgefunden. Im Rahmen dieser Arbeit wurde ein Konzept und modulares System entwickelt, mit dem sich das Objektverhalten anatomischer Strukturen unter Berücksichtigung des visuellen und haptischen Feedbacks als Reaktion auf die Manipulation mit chirurgischen Instrumenten simulieren läßt. Die Einsetzbarkeit dieses Konzepts wurde durch die Realisierung verschiedenster VR-basierter medizinischer Trainingssysteme gezeigt.

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Müller-Wittig, Wolfgang K.; Bockholt, Ulrich; Los Arcos, José Luis; Oppelt, Peter; Stähler, Jan; Voss, Gerrit

LAHYSTOTRAIN - VR-based Intelligent Training Environment for Laparoscopy and Hysteroscopy

2001

Richir, Simon (Ed.) et al.: Virtual Reality International Conference (VRIC) 2001. Proceedings, pp. 225-233

Virtual Reality International Conference (VRIC) <2001, Laval, France>

Rapid developments in the medical field, as an expanding knowledge base and emerging new technologies require continuing medical education to achieve life long learning and to keep the surgeons up to date. Consequently, specific training is necessary to guarantee qualification of the surgeons. The goal of LAHYSTOTRAIN is to overcome the current drawbacks of traditional training methods for laparoscopic/ hysteroscopic procedures. A computer-assisted simulator for training and quality control in laparoscopy and hysteroscopy is developed using Virtual Reality (VR), Multimedia (MM) technology, and Intelligent Tutoring Systems (ITS).

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Müller-Wittig, Wolfgang K.; Bisler, Alexander; Bockholt, Ulrich; Los Arcos, José Luis; Oppelt, Peter; Stähler, Jan; Voss, Gerrit

Lahystotrain: Development and Evaluation of a Complex Training System for Hysteroscopy

2001

Westwood, James D. (Ed.): Medicine Meets Virtual Reality 2001. Proceedings : Outer Space, Inner Space, Virtual Space. Amsterdam: IOS Press; Ohmsha, 2001. (Studies in Health Technology and Informatics 81), pp. 336-340

Medicine Meets Virtual Reality (MMVR) <9, 2001, Newport Beach, CA, USA>

Hysteroscopy has already become an irreplaceable method in gynaecoloic diagnosis and therapy. In the diagnostic case the hysteroscope with a 30° optic is insert transvaginally, in the therapeutic case the resctoscope with a 12° optic is used. The endoscoppic intervention requires special surgical skills for endoscope handling and remote instrument control. To acquire these skills currently hands-on training in clinical praxis has become standard, which is linked with higher danger for the women. To overcome current drawbacks of traditional training methods the European project LAHYSTOTRAIN was set up, that tries to combine Virtual Reality (VR), Multimedia (MM) technology, and Intelligent Tutoring Systems (ITS) to develop an alternative training system for hysteroscopic interventions. The first prototype of the LAHYSTOTRAIN demonstrator has been shown on several European conferences. An evaluation of the system was performed, with the idea, to collect feedback and impressions, that should be considered in further developments. This paper presents the LAHYSTOTRAIN prototype and the results of these evaluations.

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Becker, Mario; Müller-Wittig, Wolfgang K. (Betreuer); Felger, Wolfgang (Betreuer); Voss, Gerrit (Betreuer)

Registration of anatomical structures based on high frequency ultrasound data for intraoperative support

2001

Darmstadt, TU, Diplomarbeit, 2001

In modern medicine, computer support becomes more and more important. Especially the combination of operation planing and the use of the planing results during an operation can help to optimize the work of surgeons. To use the planing data intraoperatively, the virtual world, containing the planing information must be matched with the real situation in the operation room. This is the goal of the Registration process. It determines a transformation to project preoperative data onto the patient inside the operation room. Actually this registration is done by fixing screws to the patient, which can be found within the CT dataset and measured mechanically during the operation. Affixing these screws efforts an additional operation and is an additional risk for the patient. The goal of this work was the evaluation of an alternative approach for the registration, using an intraoperative ultrasoundsystem, which is able to measure anatomical landmarks. To realize this task, a suited matching algorithm is used. This algorithm works on the segmented object of the anatomical region on one hand and on contours of the same region, measured by an intraoperatively attached ultrasound device on the other hand. The matching algorithm will find the transformation, which projects the contours onto the surface of the anatomical region. This transformation is the registration. In this diploma thesis a capable matching algorithm was founds and a system implementing this registration approach was developed and evaluated.

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Jegathese, Reginald; Song, Meehae; Quick, Jochen; Wang, Haibin; Zhong, Yongmin; Müller-Wittig, Wolfgang K.

Virtual Factory for Electronics Assembly Industry

2001

Institute of Control, Automation and Systems Engineers (ICASE), Korea: Proceedings of International Conference on Control, Automation and Systems. ICCAS 2001, pp. 488-490

International Conference on Control, Automation and Systems (ICCAS) <2001, Cheju, Korea>

Funded by the Singapore National Science and Technology Board (NSTB), CAMTech is collaborating with a Singaporean research institute and two industry partners with the objective to improve electronics assembly processes. The goal of this project is to visualise the behaviour of an electronics assembly industry by simulating, visualising the discrete events of the entire manufacturing processes and observing the flow of materials, size of buffers, and line balancing. The traditional scenario - from the customer placing order for a product to delivery - goes through various phases including manufacturing the product. Several major electronics manufacturing stages can be addressed: fabrication, assembly, testing, and packing. Each of these stages accounts for set up, process, failure, and wait time periods. A delay in one process will accumulate over to the future delays. To simulate the discrete events a general-purpose simulation system has been employed. For modelling and visualisation CASUS (Computer Animation of Simulation Traces) system has been used developed by Fraunhofer Institute for Computer Graphics (Fraunhofer-IGD). This work focuses on the prototype interface between simulation trace file and CASUS animation scripts. The final system provides a 3-D visualisation of electronics assembly processes based on event oriented simulator data.

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Los Arcos, José Luis; Müller-Wittig, Wolfgang K.; Fuente, Oscar; Orúe, Leire; Arroyo, Eder; Leaznibarrutia, Igor; Santander, Judit

LAHYSTOTRAIN: Integration of Virtual Environments and ITS for Surgery Training

2000

Gauthier, Gilles (Ed.) et al.: Intelligent Tutoring Systems. Proceedings. Berlin, Heidelberg, New York: Springer, 2000. (Lecture Notes in Computer Science (LNCS) 1839), pp. 43-52

International Conference on Intelligent Tutoring Systems (ITS) <5, 2000, Montreal, Canada>

Minimally invasive surgery has revolutionised the surgeon's approach by using optical systems to inspect cavities of the human body and by using small instruments to perform surgical procedures. This paper presents the LAHYSTOTRAIN demonstrator a training system for laparoscopy and hysteroscopy, two types of minimally invasive surgery techniques, combining a Virtual Reality Simulator (VRS), which contains virtual anatomical structures and simulates endoscope surgical instruments, a Basic Training System (BTS), that provides web based theoretical training, and an agent-based tutoring system, the Advanced Training System (ATS), oriented to supervise the execution of the practical exercises providing proactive and reactive explanations and emulating the behaviour of some persons involved in the operating theatre like the nurse, assistant surgeon and anaesthetist.