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Konzeption, Implementierung und Integration einer Komponente zur inkrementellen Bezeichner- und Operatoranalyse innerhalb des PSGs
Herder, Jens
Der Programmier System Generator - PSG - des Fachgebiets Praktische Informatik in Darmstadt erzeugt aus einer Sprachdefinition eine sprachspezifische Programmierumgebung. Diese besteht u. a. aus einem Editor, welcher syntaktische und semantische Fehler von Programmfragmenten, die nicht vollständig sein müssen, erkennen kann. Dem Benutzer werden per Menü Fehlerkorrekturen angeboten. Neben der freien Texteingabe besteht die Möglichkeit, den Text nur mit Hilfe von Menüs zu verfeinern. Teil dieses Editors ist die Bezeichneranalyse. Sie dient als Hilfsmittel für den Benutzer, indem für jede Stelle eines Programmfragmentes die gültigen Bezeichner ausgegeben werden können. Die Kontextanalyse setzt die Berechnung auf den von der Bezeichneranalyse erzeugten Daten auf, um semantische Fehler zu erkennen. Die bis zu dieser Arbeit verwendete Bezeichneranalyse im PSG unterstützt nur einfache Sprachkonzepte (z. B. Fortran und Pascal). Die Gültigkeitskonzepte der Bezeichner von weiterentwickelten Sprachen (z. B. Modula-2, CHILL, Ada oder Pascal-XT) sind nicht vollständig modellierbar. Wir stellen ein neues Konzept zur Definition und Berechnung der Bezeichneranalyse vor, das alle uns bekannten Sprachen mit statischer Typbindung unterstützt. Hierfür haben wir die Sprache BIS - Bezeichneridentifikationssprache - definiert. Die Methode ist verwandt mid dem Zwischencode für geordnete Attributierte Grammatiken. Für jeden Knoten des Abstrakten Syntaxbaumes wird mit Hilfe von BIS ein Code für eine abstrakte Maschine, welche die Bezeichneranalyse durchführt, geschrieben. Im Gegensatz zu herkömlichen Methoden (verkettete Symboltabellen) wird für jeden Punkt innerhalb eines Programmes for der Anfrage durch den Benutzer oder der Kontextanalyse die Menge der gültigen Bezeichner berechnet. Die Kosten für eine Anfrage sind dadurch minimal. Diese abstrakte Maschine teilt sich in zwei unabhängige Maschinen auf, zum einen in die S-Maschine, die die speziellen Operationen der Bezeichneranalyse durchführt, und zum anderen in die G-Maschine, die den Datenfluss und die Auswertung steuert. Diese Aufteilung ermöglicht den Austausch der S-Maschine durch eine andere, welche neue Anwendungsgebiete erschliesst, z. B. die eines Praeprozessors. Die G-Maschine arbeitet inkrementell; es werden nur die Codeschablonen neu ausgewertet, deren geerbten Attribute sich geändert haben. Dazu müssen die Daten, die in einer Codeschablone hinein- und hinausfliessen, abgelegt werden. Dies ergibt bei grossen Programmfragmenten eine immense Rechenzeiteinsparung auf Kosten des Speicherplatzes. Die Funktionsweise wird an einer kleinen Beispielsprache demonstriert, die zu Pascal ähnlich ist. Diese besitzt Konstrukte zum Import und Export von Daten und Datentypen zwischen Programmfragmenten. Im Prototyp kann die inkrementelle Arbeitsweise abgeschaltet werden und ermöglicht einen guten Vergleich der Verfahren.
Specification and Implementration of a Texture Synthesis Language (1990)
Herder, Jens
Texturen können als Oberflächenstrukturen realer Objekt aufgefasst werden und sind Variationen in Farbe, Geometrie, Transparenz, usw.. Im Gegensatz zu Algorithmen für die künstliche Generierung von Texturen gibt es nur wenige Ansätze zu Textur-Synthese-Sprachen oder zu Hilfsmittel für die Textur-Beschreibung. Die bekannten Werkzeuge decken zudem jeweils nur Teilgebiete der Generierung ab. Mit HiLDTe (Hierachical Language for the Description of Textures) ist nun eine Sprache entwickelt worden, mit der möglichst alle bekannten Texturtypen beschrieben werden können. HiLDTe basiert auf einem am Fachgebiet GRIS entwickelten Texturmodell, in dem Texturen generische, eventuell komplex zusammengesetzte Objekte repräsentieren. Aufgabe dieser Arbeit war es nun, Konzepte für die Sprache HiLDTe zu entwickeln, eine entsprechende Grammatik aufzubauen und mit Hilfe der UNIX-Werkzeuge LEX und YACC einen Compiler zu implementieren, mit dem ein ausführbarer Zwischen-Code für die in HiLDTe spezifizierten Texturen erstellt wird.
A Prototype of an Interface Builder for the Common Lisp Interface Manager - CLIB (1993)
Hesse, Jan ; König, Rainer ; Logi, Filippo ; Herder, Jens
The Common Lisp Interface Manager (CLIM) is used to develop graphical user interfaces for Lisp-basedapplications. With the prototype of the CLIM interface Builder (CLIB) the programmer can generate code for CLIM interactively. The developing process will be fast and less prone to errors. With this new tool, the interactive rapid prototyping reduces costs of a specification phase. Here we present the concept and first results of the prototype of CLIB.
Articulation Simulation for an Intelligent Dental Care System (1994)
Kunii, Tosiyasu L. ; Herder, Jens ; Myszkowski, Karol ; Okunev, Oleg ; Okuneva, Galina G. ; Ibusuki, Masumi
CAD/CAM techniques are used increasingly in dentistry for design and fabrication of teeth restorations. An important issue is preserving occlusal contacts of teeth after restoration. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surface, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming. Most existing computer systems ignore completely such an articulation check, or perform the check at the level of a tooth and its immediate neighbors. We present a new mathematical model and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is elimination of the use of mechanical articulators and manual adjustment in the process of designing dental restorations and articulation diagnostic. The mathematical model is based upon differential topological modeling of the jawbs considered as a mechanical system. The user interface exploits metaphors that are familiar to dentists from everyday practice. A new input device designed specifically for use with articulation simulation is proposed.
Visual Simulation of the Chewing Process for Dentistry (1995)
Myszkowski, Karol ; Okuneva, Galina ; Herder, Jens ; Kunii, Tosiyasu L. ; Ibusuki, Masumi
CAD/CAM techniques are increasingly used in dentistry for the design and fabrication of teeth restorations. Important concerns are the correction of articulation problems that existed beforetreatment and the prevention of treatment-generated problems. These require interactive evaluation of the occlusal surfaces of teeth during mastication. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surfaces, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming and provide little visual information. We present new visual tools and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is visual representation of characteristics relevant to the chewing process. The simulation is based on the construction of distance maps, which are visual representations of the distributions of the distances of points in a tooth to the opposite jaw. We use rasterizing graphics hardware for fast calculation of the distance maps. Distance maps are used for collision detection and for the derivation of various characteristics showing the distribution of load on the teeth and the chewing capability of the teeth. Such characteristics can be calculated for particular positions of the jaws; cumulative characteristics are used to describe the properties of jaw movement. This information may be used for interactive design of the occlusal surfaces of restorations and for jaw articulation diagnosis. We also demonstrate elements of a user interface that exploit metaphors familiar to dentists from everyday practice.
A Virtual Reality Interface to an Intelligent Dental Care System (1996)
Herder, Jens ; Myszkowski, Karol ; Kunii, Tosiyasu L. ; Ibusuki, Masumi
Visualization and analysis of occlusion for human jaws using a "functionally generated path" (1996)
Myszkowski, Karol ; Herder, Jens ; Kunii, Tosiyasu L. ; Ibusuki, Masumi
Dynamic characteristics of occlusion during lower jaw motion are useful in the diagnosis of jaw articulation problems and in computer-aided design/manufacture of teeth restorations. The Functionally Generated Path (FGP), produced as a surface which envelops the actual occlusal surface of the moving opponent jaw, can be used for compact representation of dynamic occlusal relations. In traditional dentistry FGP is recorded as a bite impression in a patient’s mouth. We propose an efficient computerized technique for FGP reconstruction and validate it through implementation and testing. The distance maps between occlusal surfaces of jaws, calculated for multiple projection directions and accumulated for mandibular motion, provide information for FGP computation. Rasterizing graphics hardware is used for fast calculation of the distance maps. Real-world data are used: the scanned shape of teeth and the measured motion of the lower jaw. We show applications of FGP to analysis of the occlusion relations and occlusal surface design for restorations.
The Pioneer sound field control system at the University of Aizu Multimedia Center (2001)
Amano, Katsumi ; Matsushita, Fumio ; Yanagawa, Hirofumi ; Cohen, Michael ; Herder, Jens ; Koba, Yoshiharu ; Tohyama, Mikio
The PSFC, or Pioneer sound field control system, is a DSP-driven hemispherical 14-loudspeaker array, installed at the University of Aizu Multimedia Center. Collocated with a large screen rear-projection stereographic display the PSFC features realtime control of virtual room characteristics and direction of two separate sound channels, smoothly steering them around a configurable soundscape. The PSFC controls an entire sound field, including sound direction, virtual distance, and simulated environment (reverb level, room size and liveness) for each source. It can also configure a dry (DSP-less) switching matrix for direct directionalization. The PSFC speaker dome is about 14 m in diameter, allowing about twenty users at once to comfortably stand or sit near its sweet spot.
Sound Spatialization Resource Management in Virtual Reality Environments (1997)
Herder, Jens ; Cohen, Michael
In a virtual reality environment users are immersed in a scene with objects which might produce sound. The responsibility of a VR environment is to present these objects, but a system has only limited resources, including spatialization channels (mixels), MIDI/audio channels, and processing power. The sound spatialization resource manager controls sound resources and optimizes fidelity (presence) under given conditions. For that a priority scheme based on human psychophysical hearing is needed. Parameters for spatialization priorities include intensity calculated from volume and distance, orientation in the case of non-uniform radiation patterns, occluding objects, frequency spectrum (low frequencies are harder to localize), expected activity, and others. Objects which are spatially close together (depending on distance and direction) can be mixed. Sources that can not be spatialized can be treated as a single ambient sound source. Important for resource management is the resource assignment, i.e., minimizing swap operations, which makes it desirable to look-ahead and predict upcoming events in a scene. Prediction is achieved by monitoring objects’ speed and past evaluation values. Fidelity is contrasted for Zifferent kind of resource restrictions and optimal resource assignment based upon unlimited dynamic scene look-ahead. To give standard and comparable results, the VRML 2.0 specification is used as an application programmer interface. Applicability is demonstrated with a helical keyboard, a polyphonic MIDI stream driven animation including user interaction (user moves around, playing together with programmed notes). The developed sound spatialization resource manager gives improved spatialization fidelity under runtime constraints. Application programmers and virtual reality scene designers are freed from the burden of assigning and predicting the sound sources.
Visual Simulation of the Chewing Process for Dentistry (1997)
Myszkowski, Karol ; Okuneva, Galina ; Herder, Jens ; Kunii, Tosiyasu L. ; Ibusuki, Masumi
CAD/CAM techniques are increasingly used in dentistry for the design and fabrication of teeth estorations. Important concerns are the correction of articulation problems that existed before treatment and the prevention of treatment-generated problems. These require interactive evaluation of the occlusal surfaces of teeth during mastication. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surfaces, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming and provide little visual information. We present new visual tools and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is visual representation of characteristics relevant to the chewing process. The simulation is based on the construction of distance maps, which are visual representations of the distributions of the distances of points in a tooth to the opposite jaw. We use rasterizing graphics hardware for fast calculation of the distance maps. Distance maps are used for collision detection and for the derivation of various characteristics showing the distribution of load on the teeth and the chewing capability of the teeth. Such characteristics can be calculated for particular positions of the jaws; cumulative characteristics are used to describe the properties of jaw movement. This information may be used for interactive design of the occlusal surfaces of restorations and for jaw articulation diagnosis. We also demonstrate elements of a user interface that exploit metaphors familiar to dentists from everyday practice.
Information Retrieval and Database Architecture for Conventional Japanese Character Dictionaries (1997)
Schmitt, Lothar M. ; Herder, Jens ; Bhalla, Subhash
The cycle of abstraction-reconstruction which occurs as a fundamental principle in the development of culture and in cognitive processes is described and analyzed. This approach leads to recognition of boundary conditions for and directions of probable development of cognitive tools. It is shown how the transition from a conventional Japanese-English character dictionary to a multi-dimensional language database is an instance of such an abstraction-reconstruction cycle. The different phases of the design of a multi-dimensional language database based upon different computer software technologies are properly placed in this cycle. The methods used include the use of UNIX software tools, classical database methods as-well-as the use of search engines based upon full text search in this process. Several directions of application and extension for a multi-dimensional language database are discussed from the general point of view of an abstraction-reconstruction cycle.
Enhancing Perspicuity of Objects in Virtual Reality Environments (1997)
Herder, Jens ; Cohen, Michael
In an information-rich Virtual Reality (VR) environment, the user is immersed in a world containing many objects providing that information. Given the finite computational resources of any computer system, optimization is required to ensure that the most important information is presented to the user as clearly as possible and in a timely fashion. In particular, what is desired are means whereby the perspicuity of an object may be enhanced when appropriate. An object becomes more perspicuous when the information it provides to the user becomes more readily apparent. Additionally, if a particular object provides high-priority information, it would be advantageous to make that object obtrusive as well as highly perspicuous. An object becomes more obtrusive if it draws attention to itself (or equivalently, if it is hard to ignore). This paper describes a technique whereby objects may dynamically adapt their representation in a user's environment according to a dynamic priority evaluation of the information each object provides. The three components of our approach are: - an information manager that evaluates object information priority, - an enhancement manager that tabulates rendering features associated with increasing object perspicuity and obtrusion as a function of priority, and - a resource manager that assigns available object rendering resources according to features indicated by the enhancement manager for the priority set for each object by the information manager. We consider resources like visual space (pixels), sound spatialization channels (mixels), MIDI/audio channels, and processing power, and discuss our approach applied to different applications. Assigned object rendering features are implemented locally at the object level (e.g., object facing the user using the billboard node in VRML 2.0) or globally, using helper applications (e.g., active spotlights, semi-automatic cameras).
A Virtual Reality Sound System Using Room-Related Transfer Functions Delivered Through a Multispeaker Array: the PSFC at the University of Aizu Multimedia Center (1998)
Amano, Katsumi ; Matsushita, Fumio ; Yanagawa, Hirofumi ; Cohen, Michael ; Herder, Jens ; Martens, William ; Koba, Yoshiharu ; Tohyama, Mikio
The PSFC, or Pioneer Sound Field Controller, is a DSP-driven hemispherical loudspeaker array, installed at the University of Aizu Multimedia Center. The PSFC features realtime manipulation of the primary components of sound spatialization for each of two audio sources located in a virtual environment, including the content (apparent direction and distance) and context (room characteristics: reverberation level, room size and liveness). In an alternate mode, it can also direct the destination of the two separate input signals across 14 loudspeakers, manipulating the direction of the virtual sound sources with no control over apparent distance other than that afforded by source loudness (including no simulated environmental reflections or reverberation). The PSFC speaker dome is about 10 m in diameter, accommodating about fifty simultaneous users, including about twenty users comfortably standing or sitting near its ``sweet spot,'' the area in which the illusions of sound spatialization are most vivid. Collocated with a large screen rear-projection stereographic display, the PSFC is intended for advanced multimedia and virtual reality applications.
Symbolic representations of exclude and include for audio sources and sinks: Figurative suggestions of mute/solo & cue and deafen/confide & harken (1998)
Cohen, Michael ; Herder, Jens
Tools and Widgets for Spatial Sound Authoring (1998)
Herder, Jens
Perceptual criteria for eliminating reflectors and occluders from the rendering of environmental sound (1999)
L. Martens, William ; Herder, Jens
Given limited computational resources available for the rendering of spatial sound imagery, we seek to determine effective means for choosing whatcomponents of the rendering will provide the most audible differences in the results. Rather than begin with an analytic approach that attempts to predict audible differences on the basis of objective parameters, we chose to begin with subjective tests of how audibly different the rendering result may be heard to be when that result includes two types of sound obstruction: reflectors and occluders. Single-channel recordings of 90 short speech sounds were made in an anechoic chamber in the presence and absence of these two types of obstructions, and as the angle of those obstructions varied over a 90 degree range. These recordings were reproduced over a single loudspeaker in that anechoic chamber, and listeners were asked to rate how confident they were that the recording of each of these 90 stimuli included an obstruction. These confidence ratings can be used as an integral component in the evaluation function used to determine which reflectors and occluders are most important for rendering.
A filtering model for efficient rendering of the spatial image of an occluded virtual sound source (1999)
Martens, William L. ; Herder, Jens ; Shiba, Yoshiki
Rendering realistic spatial sound imagery for complex virtual environments must take into account the effects of obstructions such as reflectors and occluders. It is relatively well understood how to calculate the acoustical consequence that would be observed at a given observation point when an acoustically opaque object occludes a sound source. But the interference patterns generated by occluders of various geometries and orientations relative to the virtual source and receiver are computationally intense if accurate results are required. In many applications, however, it is sufficient to create a spatial image that is recognizable by the human listener as the sound of an occluded source. In the interest of improving audio rendering efficiency, a simplified filtering model was developed and its audio output submitted to psychophysical evaluation. Two perceptually salient components of occluder acoustics were identified that could be directly related to the geometry and orientation of a simple occluder. Actual occluder impulse responses measured in an anechoic chamber resembled the responses of a model incorporating only a variable duration delay line and a low-pass filter with variable cutoff frequenc
A Sound Spatialization Server for a Speaker Array as an Integrated Part of a Virtual Environment (1998)
Ishikawa, Kimitaka ; Hirose, Minefumi ; Herder, Jens
Spatial sound plays an important role in virtual reality environments, allowing orientation in space, giving a feeling of space, focusing the user on events in the scene, and substituting missing feedback cues (e.g., force feedback). The sound spatialization framework of the University of Aizu, which supports number of spatialization backends, has been extended to include a sound spatialization server for a multichannel loudspeaker array (Pioneer Sound Field Control System). Our goal is that the spatialization server allows easy integration into virtual environments. Modeling of distance cues, which are essential for full immersion, is discussed. Furthermore, the integration of this prototype into different applications allowed us to reveal the advantages and problems of spatial sound for virtual reality environments.
647 - Zweite Satzung zur Änderung der Prüfungsordnung für die Bachelorstudiengänge „Elektro- und Informationstechnik“ und „Elektro- und Informationstechnik“ (dual) an der Hochschule Düsseldorf vom 13.02.2019 (2019)
Aufgrund der §§ 2 Abs. 4, 64 Abs. 1 des Gesetzes über die Hochschulen des Landes Nordrhein-Westfalen (HG NRW) vom 16.09.2014 (GV. NRW. S. 547) in der aktuell gültigen Fassung hat die Hochschule Düsseldorf die folgende Ordnung als Satzung erlassen.
Interactive Realtime Terrain Visualization for Virtual Set Applications (2003)
Griesert, Arnfried ; Walczak, Oliver ; Herder, Jens
Virtual set environments for broadcasting become more sophisticated as well as the visual quality improves. Realtime interaction and production-specific visualization implemented through plugin mechanism enhance the existing systems like the virtual studio software 3DK. This work presents an algorithm which can dynamically manage textures of high resolution by prefetching them depending on their requirement in memory and map them on a procedural mesh in realtime. The main goal application of this work is the virtual representation of a flight over a landscape as part of weather reports in virtual studios and the interaction by the moderator.

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