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In this paper we propose an integrated immersive augmented reality solution for a software tool supporting spacecraft design and verification. The spacecraft design process relies on expertise in many domains, such as thermal and structural engineering. The various subsystems of a spacecraft are highly interdependent and have differing requirements and constraints. In this context, interactive visualizations play an important role in making expert knowledge accessible. Recent immersive display technologies offer new ways of presenting and interacting with computer-generated content. Possibilities and challenges for spacecraft configuration employing these technologies are explored and discussed. A user interface design for an application using the Microsoft HoloLens is proposed. To this end, techniques for selecting a spacecraft component and manipulating its position and orientation in 3D space are developed and evaluated. Thus, advantages and limitations of this approach to spacecraft configuration are revealed and discussed.
Based on experience in teaching programming, we developed the integrated development environment (IDE) 5Code especially to support beginners. As a first step, a simple, understandable formula was developed how to advance from the problem to the program in 5 operative steps:
read it → get it → think it → note it → code it.
In order to reduce the cognitive load of the learners effectively, 5Code was designed such that all 5 steps are permanently presented, accessible and executable. Thus, learners are provided with the entire programming context from presentation of the task via own notes and annotations to the code area. Learners can mark and annotate any part of the given task’s text; these annotations can be edited as notes with own comments. Furthermore, the notes can be dragged into the code area, where they are shown as comments in the coding language. Any modifications in the comments are synchronized between notes and code. 5Code is implemented as a web-application. It is used in university introductory courses on object oriented programming.
An international, collaborative investigation is undertaken to evaluate the relative merits and limitations of various numerical methods and experimental measurement techniques, specifically for the analysis of flapping-wing propulsion. A finite aspect-ratio configuration is extensively investigated, both quantitatively and qualitatively, in a low-speed wind tunnel. Direct force measurements are made, as well as time-accurate and time-averaged laser Doppler velocimetry and unsteady flow visualization. The reduced frequency, mean angle of attack, aspect ratio and Reynolds number are varied in the experiments. The experiment is numerically simulated using flatplate theory, two and three-dimensional panel codes, and two and three-dimensional Euler and Navier- Stokes solvers. The ability of each of the methods to capture important aspects of the flow physics are evaluated through comparisons with each other and the experimental data. Additionally, the comparisons indicate areas where further research is needed. The collaborative effort provides a survey of available capabilities and provides a fixed set of flappingwing data for others to compare against.
The discipline of engineering secure software and services brings together researchers and practitioners from software, services, and security engineering. This interdisciplinary community is fairly new, it is still not well integrated and is therefore confronted with differing perspectives, processes, methods, tools, vocabularies, and standards. We present a Common Body of Knowledge (CBK) to overcome the aforementioned problems. We capture use cases from research and practice to derive requirements for the CBK. Our CBK collects, integrates, and structures knowledge from the different disciplines based on an ontology that allows one to semantically enrich content to be able to query the CBK. The CBK heavily relies on user participation, making use of the Semantic MediaWiki as a platform to support collaborative writing. The ontology is complemented by a conceptual framework, consisting of concepts to structure the knowledge and to provide access to it, and a means to build a common terminology. We also present organizational factors covering dissemination and quality assurance.
This paper presents a conceptual framework for security engineering, with a strong focus on security requirements elicitation and analysis. This conceptual framework establishes a clear-cut vocabulary and makes explicit the interrelations between the different concepts and notions used in security engineering. Further, we apply our conceptual framework to compare and evaluate current security requirements engineering approaches, such as the Common Criteria, Secure Tropos, SREP, MSRA, as well as methods based on UML and problem frames. We review these methods and assess them according to different criteria, such as the general approach and scope of the method, its validation, and quality assurance capabilities. Finally, we discuss how these methods are related to the conceptual framework and to one another.
In today’s market research mechanisms multi modal technologies are significant tools to perform flexible and price efficient studies for not only consumer products but also consumer goods. Current appraisal mechanisms in combination with applied computer graphics can improve the assessment of a product’s launch in the very early design phase or an innovation process. The combination of online questionnaires, Virtual Reality (VR) applications and a database management system offers a powerful tool to let a consumer judge products as well as innovated goods even without having produced a single article. In this paper we present an approach of consumer good studies consisting of common as well as interactive VR product presentations and online questionnaires bases on a bidirectional database management solution to configure and manage numerous studies, virtual sets, goods and participants in an effective way to support the estimation of the received data. Non-programmers can create their test environment including a VR scenario very quickly without any effort. Within the extensive knowledge of consumer goods, marketing instruments can be defined to shorten and improve the rollout process in the early product stages.
A filtering model for efficient rendering of the spatial image of an occluded virtual sound source
(1999)
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 frequency.
A filtering model for efficient rendering of the spatial image of an occluded virtual sound source
(1999)
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
This article describes the possibilities and problems that occur using the SteamVR tracking 2.0 system as a camera tracking system in a virtual studio and explains an approach for implementation and calibration within a professional studio environment. The tracking system allows for cost effective deployment. Relevant application fields are also mixed reality recording and streaming of AR and VR experiences.
Klassifikationen
IPC
C12N15/81; C12N15/82; C12P17/12; C12P7/42;
CPC
C12N15/815 (EP); C12P17/12 (EP);
Acquiring human motion data from video images plays an important role in the field of computer vision. Ground truth tracking systems require markers to create high quality motion data. But in many applications it is desired to work without markers. In recent years affordable hardware for markerless tracking systems was made available at a consumer level. Efficient depth camera systems based on Time-of-Flight sensors and structured light systems have made it possible to record motion data in real time. However, the gap between the quality of marker-based and markerless systems is high. The error sources of a markerless motion tracking pipeline are discussed and a model-based filter is proposed, which adapts depending on spatial location. The proposed method is then proven to be more robust and accurate than the unfiltered data stream and can be used to visually enhance the presence of an actor within a virtual environment in live broadcast productions.
A new robust design for imperfection sensitive stiffened cylinders used in aerospace engineering
(2015)
We present a pattern system/or security requirements engineering, consisting of security problem frames and concretized security problem frames. These are special kinds of problem frames that serve to structure, characterize, analyze, and finally solve software development problems in the area of software and system security. We equip each frame with formal preconditions and postconditions. The analysis of these conditions results in a pattern system that explicitly shows the dependencies between the different frames. Moreover, we indicate related frames, which are commonly used together with the considered frame. Hence, our approach helps security engineers to avoid omissions and to cover all security requirements that are relevant for a given problem.
The authors present a security engineering process based on security problem frames and concretized security problem frames. Both kinds of frames constitute patterns for analyzing security problems and associated solution approaches. They are arranged in a pattern system that makes dependencies between them explicit. The authors describe step-by-step how the pattern system can be used to analyze a given security problem and how solution approaches can be found. Afterwards, the security problems and the solution approaches are formally modeled in detail. The formal models serve to prove that the solution approaches are correct solutions to the security problems. Furthermore, the formal models of the solution approaches constitute a formal specification of the software to be developed. Then, the specification is implemented by generic security components and generic security architectures, which constitute architectural patterns. Finally, the generic security components and the generic security architecture that composes them are refined and the result is a secure software product built from existing and/or tailor-made security components.
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.
We present a security engineering process based on security problem frames and concretized security problem frames. Both kinds of frames constitute patterns for analyzing security problems and associated solution approaches. They are arranged in a pattern system that makes dependencies between them explicit. We describe step-by-step how the pattern system can be used to analyze a given security problem and how solution approaches can be found. Further, we introduce a new frame that focuses on the privacy requirement anonymity.
Today, the use of renewable energies and recycling of climate-changing gases are increasingly important. In this context,coupling of methanation with small, decentralized CO2sources such as biogas plants provides one possibility. However,fluctuating availability of renewables for hydrogen production in combination with small storage volumes result in anenhanced demand for dynamic process operation. This leads to new research challenges with respect to the required cata-lysts and the overall process design. To draw reliable conclusions about the catalytic performance under dynamic processoperation, the mechanism of the methanation reaction as well as typical deactivation procedures of the catalyst appliedunder steady-state conditions have to be reviewed thoroughly.
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 practical system has only limited resources, including spatialization channels (mixels), MIDI/audio channels, and processing power. A sound spatialization resource manager, introduced in this thesis, controls sound resources and optimizes fidelity (presence) under given conditions, using a priority scheme based on psychoacoustics. Objects which are spatially close together can be coalesced by a novel clustering algorithm, which considers listener localization errors. Application programmers and VR scene designers are freed from the burden of assigning mixels and predicting sound source locations. The framework includes an abstract interface for sound spatialization backends, an API for the VR environments, and multimedia authoring tools.
A Sound Spatialization Server for a Speaker Array as an Integrated Part of a Virtual Environment
(1998)
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.