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Besides application fields such as entertainment and marketing, the technology of Virtual Reality is also applied in research and practice, including domains such as automotive, architecture, and construction. Furthermore, VR has been utilized for several activities in design practice and design research. However, the impact of this technology on design as a profession remains to be investigated. Thus, in the present study, an integrative literature review is presented to investigate the potential impact of Virtual Reality on design research and design practice. The findings indicate potential advantages on different levels. VR has the potential to enhance problem identification due to laboratorial environments and to foster co-creation due to enhanced motivation and the establishment of synergies between the involved stakeholders. Furthermore, it supports prototyping activities due to its capabilities for realistic scaling and perspectives. And lastly, VR has proven to be advantageous for design evaluations and reviews due to its visualization and immersion potential. Drawbacks of using VR for design research and practice involve technical limitations such as restricted field of view, limited performance, but also aspects such as missing accuracy for prototyping and the absence of haptic feedback. Future work will involve an extended review involving further literature and application domains.
In the design of urban public spaces, the inclusion of diverse voices enhances the development of products and services by synchronising designer expertise with people’s preferences. Multiple participatory methods exist, each with their respective benefits and drawbacks in terms of the quality of results, time and cost needed for preparing and conducting studies, and knowledge required for participation. Providing more concrete representations of abstract or intangible design concepts would be beneficial for laypeople unfamiliar with design or the case study. We propose a Virtual Reality (VR) platform to discover subjective preferences on public waiting rooms through immersive design experiences. The VR platform was tested with 463 participants with variety in age and cultural background. Following a qualitative data analysis, we discuss the suitability of our VR platform for fostering inclusive participation and how it impacts the role of the designer, as well as propose design guidelines for future VR studies.
Computer-Aided Design (CAD) constitutes an important tool for industrial designers. Similarly, Virtual Reality (VR) has the capability to revolutionize how designers work with its increased sense of scale and perspective. However, existing VR CAD applications are limited in terms of functionality and intuitive control. Based on a comparison of VR CAD applications, ImPro, a new application for immersive prototyping for industrial designers was developed. The user evaluations and comparisons show that ImPro offers increased usability, functionality, and suitability for industrial designers.
One of the tasks PAULE[1, 2] solves is finding suitable control parameter (cp-)trajectories for a given target acoustic. These cp-trajectories can be used to synthesize speech with the articulatory speech synthesizer of the VocalTractLab (VTL) [3]. If the target acoustic contains substantial microphone noise or other background noises, occasionally PAULE optimizes not for the speech in the target, but for this background noises. By adding a speech/non-speech classifier to the feedback and planning-loop in PAULE this resynthesis of background noises should be mitigated. Unfortunately, the improvements were minor, which might be due to uninformative gradients of the classifier. The importance of informative gradients and the use classifiers to adapt PAULE to different tasks are explained and discussed.
There is high confidence for the hypothesis that in speech perception the cycles of a θ-oscillation segment the auditory signal into syllables [8]. Yet the functionality of the oscillator generating the θ-oscillation is unknown. We follow the finding that, within an auditory scene, speech is perceived as a stream given by temporal coherence [12]. We work with the hypotheses that the θ-oscillator is driven by temporal features providing this coherence. We propose a new temporal feature called O-distance, which detects the onset of a syllable - the starting point to of a θ-cycle–triggered by the temporal distance from to to the instance of the maximal rise of the loudness curve of the vowel. To extract to from the auditory signal, we use the statistical properties of this distance based on the C-center hypothesis [25], which predicts a close temporal relation of the onset consonants to the onset of a vowel. The statistics are derived from reference O-distance extracted from an articulatory database, where the minima and maxima of the loudness are related to maxima and minima of the lower incisor and tongue tip. To judge the quality of the O-distance extracted from the auditory signal, we regard the temporal deviation of the O-distance to the reference O-distance. Currently we achieve a mean deviation of 34ms.
This paper addresses the challenges and advancements in speech recognition for singing, a domain distinctly different from standard speech recognition. Singing encompasses unique challenges, including extensive pitch variations, diverse vocal styles, and background music interference. We explore key areas such as phoneme recognition, language identification in songs, keyword spotting, and full lyrics transcription. I will describe some of my own experiences when performing research on these tasks just as they were starting to gain traction, but will also show how recent developments in deep learning and large-scale datasets have propelled progress in this field. My goal is to illuminate the complexities of applying speech recognition to singing, evaluate current capabilities, and outline future research directions.
Design research is an academic issue and increasingly a success factor for industrial,organizational and social innovation. Efficient methodical support is crucial. The fiercerejection of 1st generation design methods in the early 1970s resulted in thepostmodernist attitude of "no methods", and subsequently in the strong adoption ofscientific ways of thinking for design research. The situation regarding methodologyhas been characterized by unproductive dualisms such as scientific vs. designerlymethods, normative vs. descriptive methods, research vs. design. The potential of theearly (1st generation) methods is neglected and the practical usefulness of designresearch is impeded. The suggestion for 2nd generation methods, conceived asdiscursive instruments, as discussed by Rittel and others has hardly been taken up indesign. The development of MAPS is aimed at the support of practice-oriented design,innovation and research processes. The long-term aim is the development of anintegrated knowledge and communication platform for research through design. MAPSis based upon the idea of a productive reconciliation of the strong dualisms between"scientific" and "designerly" modes of inquiry and supports the emerging concept ofdesign thinking. The paper reports on the ongoing research and development processfrom MAPS1.0 towards MAPS2.0 and beyond.
Beyond Dualisms in Methodology. An Integrative Design Research Medium "MAPS" and some Reflections
(2008)
Design research is an academic issue and increasingly an essential success factor for industrial, organizational and social innovation. The fierce rejection of 1st generation design methods in the early 1970s resulted in the postmodernist attitude of "no methods", and subsequently, after more than a decade, in the strong adoption of scientific methods, or "the" scientific method, for design research. The current situation regarding methodology is characterized by unproductive dualisms such as scientific methods vs. designerly methods, normative methods vs. descriptive methods, research vs. design. The potential of the early (1st generation) methods is neglected and the practical usefulness of design research is impeded. The suggestion for 2nd generation methods as discussed by Rittel and others has hardly been taken up in design. The development of a methodological tool / medium for research through design – MAPS1 – (which is the central part of the paper) presents the cause and catalyst for some reflections about the usability / desirability / usefulness of methodical support for the design (research) process.
Abduction Revisited
(2009)
This paper is based on the talk of the same title delivered at the “Dock of Learning” Symposium. I reflect on design research with an eye on the critical issues of our time. Design research has the potential to take on these issues; however, there are challenges. A threatening one, I see, is the divergence of design research and art research. I attempt to tackle this by examining Jonas’ Research through Design and Borgdorff’s Artistic Research with help from John Dewey’s philosophy.
We take abduction to be the central 'logical' and social "mechanism" of knowledge generation in general, applicable to everyday life, design, and the sciences. In our designerly methodological terms, we speak of ANALYSIS (the inductive phase), PROJECTION (the abductive phase) and SYNTHESIS (the deductive phase). We suppose that projection is enabled by abduction, and that understanding the abductive mechanisms in design PROJECTION is essential for the development of genuine designerly concepts of research. We hypothesize that transfer and transferability are relevant concepts and that establishing their relation to abduction is necessary. We set up quasi-experiments to examine design transfer. Based on the results of the experiments and following , we relate Peircean semiotics to his logical theory: his classes of signs are also classes of abduction. Firstly, we subscribe to Peirce's semiotic -a sign is in a triadic relation among object, interpretant and sign itself. Then we...
Effects of Deep Rolling on the Fatigue Behavior of Ti-6Al-4V at Ambient and Elevated Temperatures
(2003)
We describe ongoing and proposed work concerning incremental prosody extraction and classification for a spoken dialogue system. The system described will be tightly integrated with the SDS's speech recogntion which also works incrementally. The proposed architecture should allow for more control over the user interaction experience, for example allowing more precise and timely end-of-utterance vs. hesitation distinction, and auditive or visual back-channel generation.
Ideally, a spoken dialogue system should react without much delay to a user’s utterance. Such a system would already select an object, for instance, before the user has finished her utterance about moving this particular object to a particular place. A prerequisite for such a prompt reaction is that semantic representations are built up on the fly and passed on to other modules. Few approaches to incremental semantics construction exist, and, to our knowledge, none of those has been systematically tested on a spontaneous speech corpus. In this paper, we develop measures to test empirically on transcribed spontaneous speech to what extent we can create semantic interpretation on the fly with an incremental semantic chunker that builds a frame semantics.
We define the task of incremental or 0-lag utterance segmentation, that is, the task of segmenting an ongoing speech recognition stream into utterance units, and present first results. We use a combination of hidden event language model, features from an incremental parser, and acoustic / prosodic features to train classifiers on real-world conversational data (from the Switchboard corpus). The best classifiers reach an F-score of around 56%, improving over baseline and related work.
Telling stories is different from reading out text: a speakerreponds to the listener’s feedback and incorporates thisinto the ongoing talk. However, current computer sys-tems are unable to do this and instead just non-attentivelyread out a text, disregarding all feedback (or the absencethereof). I propose and discuss an idea for a small researchproject and a plan for how an attentive listening storytellercan be built.
Mechanical surface treatments, such as deep rolling, shot peening and laser shock peening, can significantly improve the fatigue behavior of highly stressed metallic components. Deep rolling is an especially attractive technique since it is possible to generate deep, near-surface compressive residual stresses and work hardening while retaining a relatively smooth surface finish. Indeed, this technique is best known for increasing the fatigue strength and lifetime of steel components such as crankshafts. Although most work on deep rolling has been on steels, recently it has also been applied with reasonable success to titanium alloys. Accordingly, in this investigation, we examine the effect of deep rolling on the high-cycle fatigue behavior of Ti-6Al-4V, with particular emphasis on the thermal and mechanical stability of the residual stress states and near-surface microstructures. Preliminary results on laser shock peened Ti-6Al-4V are also presented for comparison. In addition, we examine whether these surface treatments are effective in retaining fatigue strength at the higher temperatures of 300 to 450C. Based on the cyclic deformation and stress/life behavior, together with the X-ray and microstructural observations, it is found that deep rolling can be quite effective in retarding the initiation and initial propagation of fatigue cracks in Ti-6Al-4V at such higher temperatures, despite the almost complete relaxation of the residual stresses at the surface. This clearly implies that, in addition to residual stresses, near-surface microstructures, which in Ti-6Al-4V consist of ultrafine near-surface nanostructures, play a critical role in the enhancement of fatigue lifetimes by mechanical surface treatments.
We report on the investigation and realization of photonic filters based on the combination of fractional compositions of a few basic grating periods. Using a minimum set of two basic periods Lambda(1) and Lambda(2) we demonstrate comb-like few mode photonic band gap structures with arbitrary numbers of bands and frequency spacing between the bands. Optically integrated filters of different comb periods result in switchable wavelength filters for channel selection in WDM applications.
Affordances manifest possibilities of interaction with a spoken dialogsystem. For example, the act of asking a question affords to the recipient thepossibility of answering. In the system we present, the observable act of maneuveringaffords the possibility of controlling a motion. Our system thus uses the affordanceprinciple to shape the interaction: to trigger the usage of instructions that are easyto understand and process, the system gives immediate visual feedback to afforduser commands that can then be reacted upon. This tightening of the interactionloop requires an incremental processing paradigm to allow fast reactions and to beable to alter ongoing system actions. Our system is a hybrid of incremental andnon-incremental processing components, combining conventional, state graph-basedprocessing, which has the advantage of widely available toolkits and well-understooddialog management, with incremental dialog processing which allows for the tightfeedback loop that provides for quick reactions. We tested our approach in a smalluser study and found that users used simpler and setting-independent commandsmore often and were more efficient when faced with the affordance-based version ofour system.
The potential of using ASR n-best lists for dialogue systems has often been recognised (if less often realised): it is often the case that even when the top-ranked hypothesis is erroneous, a bet- ter one can be found at a lower rank. In this paper, we describe metrics for evaluating whether the same potential carries over to incremental dialogue systems, where ASR output is consumed and reacted upon while speech is still ongoing. We show that even small N can provide an advantage for semantic process- ing, at a cost of a computational overhead.
In incremental spoken dialogue systems, par- tial hypotheses about what was said are re- quired even while the utterance is still ongo- ing. We define measures for evaluating the quality of incremental ASR components with respect to the relative correctness of the par- tial hypotheses compared to hypotheses that can optimize over the complete input, the tim- ingof hypothesisformationrelative to the por- tion ofthe inputthey areabout, andhypothesis stability, defined as the number of times they are revised. We show that simple incremen- tal post-processing can improve stability dra- matically, at the cost of timeliness (from 90% of edits of hypotheses being spurious down to 10% at a lag of 320ms). The measures are not independent,and we show how system de- signers can find a desired operating point for their ASR. To our knowledge, we are the first to suggest and examine a variety of measures for assessing incremental ASR and improve performance on this basis.
We present INPROTK, a toolkit for building incremental spoken dia-logue systems. Incremental spoken dialogue systems (systems that may react whilethe user’s utterance is ongoing) are a fairly recent research topic and allow for ex-citing new features. Even though toolkits exist that help in building conventionaldialogue systems, INPROTK offers both a tested architecture for building incre-mental SDSs as well as many of the building blocks necessary when building suchsystems. With INPROTK a researcher can avoid many of the technical difficulties,which hopefully further fosters research in this area.
We present the novel task of predicting tem-poral features of continuations of user input,while that input is still ongoing. We show that the remaining duration of an ongoing word, aswell as the duration of the next can be predicted reasonably well, and we put this information touse in a system that synchronously completesa user’s speech. While we focus on collaborative completions, the techniques presented here may also be useful for the alignment of back-channels and immediate turn-taking in anincremental SDS, or to synchronously monitorthe user’s speech fluency for other reasons.
We present a component for incremental speech synthesis (iSS) and a set of applications that demonstrate its capabilities. This component can be used to increase the responsivity and naturalness of spoken interactive systems. While iSS can show its full strength in systems that generate output incrementally, we also discuss how even otherwise unchanged systems may profit from its capabilities.
In many environments (e. g. sports commentary), situations incrementally unfold over time and often the future appearance of a relevant event can be predicted, but not in all its details or precise timing. We have built a simulation framework that uses our incremental speech synthesis component to assemble in a timely manner complex commentary utterances. In our evaluation, the resulting output is preferred over that from a baseline system that uses a simpler commenting strategy. Even in cases where the incremental system overcommits temporally and requires a filled pause to wait for the upcoming event, the system is preferred over the baseline.
Dual front steering axles are quite common in multi-axled heavy duty trucks. In standard layouts of such axle combinations, the steer motions of the wheels depend not only on the rotation of the steering wheel but also on the movements of the axles. As a consequence, the model complexity of the steering system should match with the complexity of the suspension model. The development of new technologies like advanced driver assistance systems or autonomous driving can only be accomplished efficiently using extensive simulation methods. Such kind of applications demand for computationally efficient vehicle models. This paper presents a steering system model for dual front axles of heavy duty trucks which supplements the suspension model of the axles. The model takes the torsional compliance of the steering column as well as the stiffness of the tie rods and the coupling rod into account. A quasi-static solution provides a straight forward computation including the partial derivatives required for an efficient implicit solver. The steering system model matches perfectly with comparatively lean, but sufficiently accurate multibody suspension models.
We present first experimental results of the successful transfer of our monolithic integrated double-stack multi quantum well laser-modulator approach from the traditional InGaAsP/InP to the more promising InGaAlAs/InP material system. In continuous wave operation at room temperature, the devices achieved threshold currents of <21 mA, fiber coupled optical power levels up to 570 μW and static extinction ratios in the range of 15 dB/V. The measured small-signal modulation bandwidth of about 10 GHz is capacitance limited due to a conservative device layout.
We present a new method for fabrication of tunable InGaAsP-InP single mode lasers without epitaxial overgrowth. These devices show the advantage of a considerably simplified fabrication process compared to conventional tunable laser types. The lasers comprise an active Bragg reflector integrated with an uncorrugated separately pumped gain region. To overcome the extensive and expensive overgrowth step we realized a surface grating on both sides of the ridge mesa, which provides DFB operation. By adjusting the current through the Bragg reflector, the wavelength can be tuned between 1590.8 nm and 1595.2 nm. A maximum of 11 wavelength channels with an average spacing of ~0.5 nm and a constant optical output power of ~0.5 mW are addressable.
We report on dynamic measurements on antiphase complex coupled 1.55 /spl mu/m DFB lasers. The antiphase complex coupling mechanism is realized by periodically etching the active layer and quarternary InGaAsP overgrowth. This new fabrication approach results in very narrow linewidths measured on devices with rather short resonator lengths. The minimum linewidth for a 375 /spl mu/m long ridge waveguide laser was only 250 kHz at an optical output power of 4 mW. The RC-limited 3dB-bandwidth for those devices was /spl sim/6 GHz. Using circuit model corrections, the intrinsic bandwidth limitation of those lasers was found to be 17.4 GHz.
We present a toolkit for manipulating andvisualising time-aligned linguistic datasuch as dialogue transcripts or languageprocessing data. The package comple-ments existing editing tools by allowingfor conversion between their formats, in-formation extraction from the raw files,and by adding sophisticated, and easily ex-tended methods for visualising the dynam-ics of dialogue processing. To illustratethe versatility of the package, we describeits use in three different projects at our site.
Comparing Local and Sequential Models for Statistical Incremental Natural Language Understanding
(2010)
Incremental natural language understanding is the task of assigning semantic representations to successively larger prefixes of utterances. We compare two types of statistical models for this task: a) local models, which predict a single class for an input; and b), sequential models, which align a sequence of classes to a sequence of input tokens. We show that, with some modifications, the first type of model can be improved and made to approximate the output of the second, even though the latter is more informative. We show on two different data sets that both types of model achieve comparable performance (significantly better than a baseline), with the first type requiring simpler training data. Results for the first type of model have been reported in the literature; we show that for our kind of data our more sophisticated variant of the model performs better.
Participants in a conversation are normally receptive to their surroundings and their interlocutors, even while they are speaking and can, if necessary, adapt their ongoing utterance. Typical dialogue systems are not receptive and cannot adapt while uttering. We present combin-able components for incremental natural lan-guage generation and incremental speech syn-thesis and demonstrate the flexibility they can achieve with an example system that adapts to a listener's acoustic understanding problems by pausing, repeating and possibly rephrasing problematic parts of an utterance. In an evaluation, this system was rated as significantly more natural than two systems representing the current state of the art that either ignore the interrupting event or just pause; it also has a lower response time.
When dialogue systems, through theuse of incremental processing, arenot bounded anymore by strict, non-overlapping turn-taking, a whole range ofadditional interactional devices becomesavailable. We explore the use of one suchdevice, trial intonation. We elaborateour approach to dialogue managementin incremental systems, based on theInformation-State-Update approach, anddiscuss an implementation in a micro-domain that lends itself to the use ofimmediate feedback, trial intonations andexpansions. In an overhearer evaluation,the incremental system was judged as sig-nificantly more human-like and reactivethan a non-incremental version.
We present a model of semantic processing of spoken language that (a) is robust against ill-formed input, such as can be expected from automatic speech recognisers, (b) respects both syntactic and pragmatic constraints in the computation of most likely interpretations, (c) uses a principled, expressive semantic representation formalism (RMRS) with a well-defined model theory, and (d) works continuously (producing meaning representations on a word-by-word basis, rather than only for full utterances) and incrementally (computing only the additional contribution by the new word, rather than re-computing for the whole utterance-so-far). We show that the joint satisfaction of syntactic and pragmatic constraints improves the performance of the NLU component (around 10 % absolute, over a syntax-only baseline).
In this paper we do two things: a) we discuss in general terms the task of incre mental reference resolution (IRR), in particular resolution of exophoric reference, and specify metrics for measuring the performance of dialogue system components tackling this task, and b) we present a simple Bayesian filtering model of IRR that performs reasonably well just using words directly (no structure information and no hand-coded semantics): it picks the right referent out of 12 for around 50 % of real world dialogue utterances in our test corpus. It is also able to learn to interpret not only words but also hesitations, just as humans have shown to do in similar situations, namely as markers of references tohard-to-describe entities.
We describe work done at three sites on designing conversational agents capable of incremental processing. We focus on the middleware layer in these systems, which takes care of passing around and maintaining incremental information between the modules of such agents. All implementations are based on the abstract model of incremental dialogue processing proposed by Schlangen and Skantze (2009), and the paper shows what different instantiations of the model can look like given specific requirements and application areas.
19F Gas Flow Measurement of C3F7H During Constant Flow and High Frequency Oscillatory Ventilation
(2013)
The aim of the current study is the development of MRI methods that enable the investigation of gas flow mechanisms during high frequency oscillatory ventilation. This work includes flow measurements during three constant flows (19.9, 30.6 and 41.4 L min-1) and the comparison to direct numerical simulations (DNS) using a second-order-acurate finite-volume method and to data measured with a volume flow meter. 19F-MRI, DNS and flow meter data are in good agreement. Flow measurements during HFOV of 4 Hz were successfully performed and velocity profiles could be recorded at different phases of the ventilation cycle.
This paper describes a case study of assessing student's coding behavior and skills in a realistic development setting. Students had to solve typical programming problems in the context of app development for the Android platform using the Eclipse IDE. Data was analyzed using IDE as well as browser interaction logs. In addition, screen recordings of the students' interaction with the IDE provide further insight. In this paper we present the first results of our ongoing work.
This paper proposes a multi domain physical model of permanent magnet synchronous machines, considering electrical, magnetic, thermal and mechanical effects. For each component of the model, the main wave as well as lower and higher harmonic wave components of the magnetic flux and the magnetic potential difference may be considered. The permanent magnets are modeled as discrete azimuthal segments in order to consider possible partial demagnetization effects. For each magnet segment a linearized temperature dependent B-H curve is considered. The main advantage of the presented model is that time transient operational behavior of a permanent magnet synchronous machine can be considered under various electrical, magnetic, thermal and mechanical conditions. The electromagnetic condition of surface magnet machine is compared with finite element analysis.
As part of a research project to develop design solutions for concrete-masonry buildings for the Canadian market, the apparent sound insulation performance of hybrid assemblies with concrete masonry walls and wood joist floors was evaluated. In this paper, the effect of junction coupling is investigated in an ISO 15712 flanking prediction context. Airborne flanking path data predicted according to ISO 15712 are compared to data measured using the indirect ISO 10848 shielding
method. Recommendations are made on how appropriate the application of ISO 15712 is for this type of hybrid assembly.
The performance of cognitive models often depends on the settings of specific model parameters, such as the rate of memory decay or the speed of motor responses. The systematic exploration of a model’s parameter space can yield relevant insights into model behavior and can also be used to improve the fit of a model to human data. However, exhaustive parameter space searches quickly run into a combinatorial explosion as the number of parameters investigated increases. Taking an established instance-based learning task as example, we show
how simulation using parallel computing and derivative-free optimization methods can be applied to investigate the effects
of different parameter settings. We find that both global optimization methods involving genetic algorithms as well as local methods yield satisfactory results in this case. Furthermore, we show how a model implemented in a specific cognitive architecture (ACT-R) can be mathematically reformulated to prepare the application of derivative-based optimization methods which promise further efficiency gains for quantitative analysis.
It is simple to query a relational database because all columns of the tables are known and the language SQL is easily applicable. In NoSQL, there usually is no fixed schema and no query language. In this article, we present NotaQL, a data-transformation language for wide-column stores. NotaQL is easy to use and powerful. Many MapReduce algorithms like filtering, grouping, aggregation and even breadth-first-search, PageRank and other graph and text algorithms can be expressed in two or three short lines of code.
Der vorliegende Artikel skizziert die neu entwickelte Prozesskette für detailgenaue Rekonstruktion von Geometrien anhand medizinischer Bilddaten sowie die Herstellung von transparenten Modellen für experimentelle Untersuchungen mit bildgebenden Strömungsmessverfahren. Die Geometriedaten und Modelle werden für systematische Untersuchungen der komplexen Transportvorgänge in den Atemwegen bei künstlicher Beatmung mittels Hochfrequenzoszillationsventilation (HFOV) verwendet.
Differential phase contrast imaging (DPCI) enables the visualization of soft tissue contrast using X-rays. In this work we introduce a reconstruction framework based on curvelet expansion and sparse regularization for DPCI. We will show that curvelets provide a suitable data representation for DPCI reconstruction that allows preservation of edges as well as an exact analytic representation of the system matrix. As a first evaluation, we show results using simulated phantom data
The paper presents a concept and an implementation of Modelica simulation interaction using the operating system inter-process communication method of the Named Pipe. The main aim of this presented work is to implement a hardware-in-the-loop simulation (HILS) environment based on Dymola which runs on a normal Microsoft Windows Personal Com-puter. An energy storage test bench is connected by an ana-logue and digital data input/output card with the Dymola simulation computer. With this proposed system, particularly long-time simulations with sample rates up to 30 Hz can be executed very cost effective. Typical applications are simulations of drive cycles to test energy storage systems in electrified vehicles such as batteries or fuel cells. Other application ex-amples are the verification of battery models, thermal management models or battery management sys-tem (BMS) models. In this paper all methods used for implementation are described in detail. Especially the concept of inter-process communication and the concept for real-time and simulation time synchronization is discused. An application example which uses the provided concept is also shown at in this paper. In this example a longitudinal simulation of a vehicle is pre-sented. The startup phase of the internal combusting engine model and a short drive cycle in combination with a connected real battery is shown.
Early meta-level: deeper understanding of connectivity-states and consequences for state definition
(2015)
This paper deals with a simulative approach for investigating the impact of inverter pulse inhibition during field weakening operation of permanent magnet synchronous machines and asynchronous induction machines. The modelling and simulation language Modelica is used to design models for the vehicle, the electric machine and the inverter in different abstraction levels. It is shown that when using a permanent magnet synchronous machine, a sudden breakdown of the field weakening current causes induction of high voltages in the stator windings. Hence, the electric system of the vehicle has to be protected against the resulting high currents. Furthermore precautions have to be taken to avoid dangerous driving conditions because of high braking torques in an inverter fault operation mode. In the case of the asynchronous induction machine an inverter pulse inhibition poses no big problem, neither for the electric system of the vehicle, nor the driver.
This paper focuses on simulation of permanent magnet synchronous machine (PMSM) with fractional-slot windings (FSW) in Modelica. Modeling of the electrical machines with object-oriented approach is shortly described, and a new Modelica library for simulation of electrical machines is introduced. The results of simulation of PMSMs with fractional slot windings are presented and explained. Special attention is paid to the higher harmonics and subharmonics produced by the winding and their influence on machine operation.
Condition monitoring of rotor problems such as demagnetization and eccentricity in permanent magnet synchronous motors (PMSM) is essential for guaranteeing high motor performance, efficiency, and reliability. However, there are many limitations to the off-line and on-line methods currently used for PMSM rotor quality assessment. In this paper, an inverter-embedded technique for automated detection and classification of PMSM rotor faults is proposed as an alternative. The main concept is to use the inverter to perform a test whenever the motor is stopped, to detect rotor faults independent of operating conditions or load torque oscillations, which is not possible with motor current signature analysis (MCSA). The d-axis is excited with a dc+ac signal, and the variation in the inductance pattern due to the change in the degree of magnetic saturation caused by demagnetization or eccentricity is observed for fault detection. An experimental study on a 7.5kW PMSM verifies that demagnetization and eccentricity can be detected and classified independent of the load with high sensitivity.
We propose a new framework for limited angle tomographic reconstruction. Our approach is based on the observation that for a given acquisition geometry only a few (visible) structures of the object can be reconstructed reliably using a limited angle data set. By formulating this problem in the curvelet domain, we can characterize those curvelet coefficients which correspond to visible structures in the image domain. The integration of this information into the formulation of the reconstruction problem leads to a considerable dimensionality reduction and yields a speedup of the corresponding reconstruction algorithms.
The majority of industrial controlled induction machine drives are connected to the mains via a diode bridge. However; if reduction of harmonic currents and / or regenerative operation is desired; replacing the diode bridge by an active front-end (AFE) is required. This paper describes two models of an AFE: a power balance model disregarding switching effects; and an ideal switching model of a pulse width modulation (PWM) converter. Both models are controlled utilizing space phasors in a voltage oriented reference frame. Voltage oriented control (VOC) of the mains converter can be compared with field oriented control (FOC) of a machine converter. Design and parametrization of the main parts—synchronization with mains voltage; current controller and DC voltage controller—are described in detail. Additionally; simulation results proving the implementation and demonstrating possible investigations as well as an outlook on further enhancements are presented.
Two state-of-the-art machine designs are mainly used in recent electric and hybrid electric vehicles: asynchronous induction machines with squirrel cage which are robust but need a current component to excite the magnetic field; and permanent magnet synchronous machines which rely on somehow more sensible parts but the magnets are able to excite a magnetic field without current. However; if speed gets high enough to reach the field weakening range; for both machine the field oriented control has to prescribe a field current sufficient to reduce the field not to exceed the voltage limits of the stator circuit. Especially for the permanent magnet synchronous machine this paper investigates whether it is possible to determine an optimal field current for every operation point to minimize either total current consumption or losses.
This paper presents a comprehensive computational fluid (CFD) model of a radial flux permanent magnet synchronous machine with interior magnets. In the CFD model the water jacket cooling and a simplified model of the topology of the distributed stator winding are considered. The heat sources of the CFD model are determined from a finite element analysis of the machine. The numerically determined temperature distributions of the machine are compared with measurement results from sensors located both in the stator and rotor. The particular focus of this paper is the analysis of the temperatures and the heat flow in the air gap and from the stator winding head and the rotor to the inner air.
The majority of the work performed for detecting eccentricity faults for permanent magnet synchronous motors (PMSM) focus on motor current signature analysis (MCSA), as it provides continuous on-line monitoring with existing current sensors. However, MCSA cannot be applied under nonstationary conditions and cannot distinguish faults with load torque oscillations, which are limitations for many PMSM drive applications. In this paper, it is shown that the d-axis inductance, L d , decreases with increase in the severity of eccentricity due to the change in the degree of magnetic saturation, and it is proposed as a new fault indicator. The inverter can be used to perform a standstill test automatically whenever the motor is stopped, to measure L d for eccentricity testing independent of load variations or oscillations, which is not possible with MCSA. An FE and experimental study on a 10hp PMSM verifies that eccentricity can be detected independent of the load with high sensitivity and reliability.
Innovative thermal model for the estimation of permanent magnet and stator winding temperatures
(2012)
In this paper an innovative thermal model for the determination of the temperatures of the permanent magnets and stator windings is presented. This model relies on one temperature sensor located in the stator core of the machine. The estimated stator winding and permanent magnet temperatures are determined by a simplified thermal lumped element network model with only two time constants. Due to the structure of the model and the measured stator core temperature the proposed thermal model is very robust. Distortion of the cooling circuit are inherently sensed such that the model can be used for the online prediction of temperatures. Experimental results based on an interior permanent magnet synchronous machine are presented to validate the presented model.
This paper introduces the new FundemantalWave library which is included in the Modelica Standard Library 3.2. The presented Modelica package provides models and components of rotating electrical three phase machines. The presented electrical machine models are fully compatible with the original Machines library of the electrical domain but rely on the concept of the magnetic potential and magnetic flux fundamental waves. In this article; the connector concept; the components and electric machine models of the FundemantalWave package will be explained. Additionally; the didactic advantages and the flexibility of the proposed package in with respect to considering more enhanced and sophisticated effects will be discussed.
In this paper a new model for the estimation of the stator winding and rotor cage temperatures of induction machines is presented. This model can be used in series applications of machines operated under dynamic load conditions where stator and rotor temperature shall be monitored. The proposed model relies on a simplified lumped element thermal equivalent circuit model where the stator core temperature serves as input quantity. The great advantage of this model is that it covers ambient and cooling conditions inherently. This leads to great simplicity and robustness. The parametrization and validation of the model through experimental data is presented. Advantages, drawbacks and possible implementations are discussed.
Computational Fluid Dynamics (CFD) and experimental investigations on a generic model of the trachea have been carried out focusing on the impact of an endotracheal tube (ETT) on the resulting flow regime. It could be shown that detailed modelling of the airway management devices is essential for proper flow prediction, but secondary details as Murphy Eyes can be neglected. Models with bending and connector promote the formation of stronger secondary flows and disturbances which persist for a longer time.
The high frequency oscillation artificial respiration technique is often the last hope for patients to survive highly damaged lung tissue. The mortality can significantly be reduced. In
comparison to conventional artificial respiration the applied volume flow rate and pressure is significantly lowered in order to avoid further damaging of lung tissue and remaining intact alveolae. However, the physical mechanism of transport of oxygen to the aeriols under high frequency oscillation is not well understood. In the upper part of the lung convection is dominant, in contrast, the gas exchange in the lower parts of the lung is mainly driven by diffusion. It is not clear how associated gradients of concentrations of different molecular species are then achieved. Highly oscillating fluid flows has been a long research topic in fluid dynamics. It is known that oscillating pressure fluctuations are able to induce secondary flows, in particular, in curved ducts and pipes. The question is, whether the trachea enforces the generation of secondary flow by its kidney like cross section geometry. The influence of molecular species of different densities onto the formation of secondary flows and the convectional transport within the trachea is investigated. In order to clarify the physical mechanisms behind flow simulations have been conducted by using state of the art CFD techniques.
The aim of this work is to improve the integration between the geotechnical and infrastructural designing, modeling and analyzing processes. Up to now these three planning stages are executed isolated and without the required data exchange between each other. This separation leads to time-consuming and expensive manual re-input of geometric and semantic data. Currently, roads are designed using the traditional approach which is based on various 2D drawings. The current design process focuses on the roadway itself, additional geotechnical conditions such as the slope angle of the dam or the position of a retaining wall are not considered. To solve these problems, a new parametric and 3D-model based approach has been developed in the research project ForBAU — The virtual construction site. This new approach is based on the traditional 2D infrastructure planning process, but includes a new parameterized 3D modeling concept. Different open data formats such as LandXML and GroundXML allow data integration with both, a parametric Computer Aided Design (CAD) system and a geotechnical engineering software. An automatic update function ensures data flow without loss of information. Usage of this new approach will accelerate the infrastructure design and provide a parametric 3D-model approach to close the gap between the geotechnical and the infrastructure planning process. This paper provides detailed information about this new integration concept and gives an overview on the various implementation steps.
The Hierarchical Layer Graph (HL graph) is a promising network topology for wireless networks with variable transmission ranges. It was introduced and analyzed by Meyer auf der Heide et al. 2004. In this paper we present a distributed, localized and resource-efficient algorithm for constructing this graph. The qualtiy of the HL graph depends on the domination radius and the publication radius, which affect the amount of interference in the network. These parameters also determine whether the HL graph is a c-spanner, which implies an energy-efficient topology. We investigate the performance on randomly distributed node sets and show that the restrictions on these parameters derived from a worst case analysis are not so tight using realistic settings. Here, we present the results of our extensive experimental evaluation, measuring congestion, dilation and energy. Congestion includes the load that is induced by interfering edges. We distinguish between congestion and realistic congestion where we also take the signal-to-interference ratio into account. Our experiments show that the HL graph contains energy-efficient paths as well as paths with a few number of hops while preserving a low congestion.
This paper overviews the state of the art in reverberant speech processing from the speech recognition viewpoint. First, it points out that the key to successful reverberant speech recognition is to account for long-term dependencies between reverberant observations obtained from consecutive time frames. Then, a diversity of approaches that exploit the long-term dependencies in various ways is described, ranging from signal and feature dereverberation to acoustic model compensation tailored to reverberation. A framework for classifying those approaches is presented to highlight similarities and differences between them.
Tools to predict sound transmission through building elements are beneficial from both amarketing and a research standpoint. Prediction models can assist with the optimization ofelement performance and often reduce both cost and time in projects. However, the morephysical phenomena are to be included in the model, the more input data that is needed,which in some cases can be quite time-consuming and costly to collect. A balance is neededbetween the input and modeling effort and the output, which is usually delivered in onethird octave frequency bands or single number ratings. Many different types of models arecommonly used, including analytical, numerical, and empirical are used, all of which haveadvantages and disadvantages. In this paper, the latter type is presented using a set ofphysical properties of lightweight wood elements, and the errors made in the prediction arequantified. The disadvantage of empirical compared to analytical modeling is that thephysical phenomena are more difficult to identify. The advantage is often the simplicityand accuracy of the prediction results.
A novel framework based on conditional emission densities for
hidden Markov models (HMMs) is proposed in this contribution to integrate speech enhancement systems with automatic speech recognition systems. In the training phase, the observed feature vectors, corrupted by background noise and reverberation, together with estimates for the interference as provided by the speech enhancement system are used for training joint densities of the observations and the interference estimates. In the decoding phase, the joint densities are transformed to conditional densities of the observed features given the interference estimates.
Thus, front end processing can be exploited for obtaining interference estimates, and the estimation errors can be modeled very effectively in a data-driven way. Connected digit recognition experiments in a simulated reverberant environment show the potential of the proposed approach: HMMs with the proposed conditional densities outperform various configurations of conventional HMMs in the logarithmic melspectral domain. This is a first step towards using conditional densities for creating synergies between front end and back end.
Index Terms: speech enhancement, robust speech recognition,
dereverberation, conditional HMM emission densities, frame-
by-frame model adaptation.
Aerospace and automotive industries employ three main techniques to set up joints between metal and fibre reinforced plastics parts (FRP); adhesive bonding, mechanical fastening with rives/bolts and a hybrid combination. A new joint technique has been developed to combine the two advantageous mechanisms form-closure and adhesion in a fibre-friendly way. Prior is established through metal structures (pins) which are perpendicularly welded onto metal surfaces with an arc-welding-process. They intrude into the FRP during lay-up and therefore set up a first connection. The composite-matrix is responsible for latter adhesive bonding and final form closure. Finite-element-analyses of cylindrically shaped joints are carried out to get detailed knowledge of the influence of parameters like pin-number, pin-position, pin-height, pin-form sleeve-geometry, and stiffness behaviour. Long calculation times of 3D-models lead to the introduction of a corresponding 2D-axisymmetric-model which is used to run parameter-studies within a reasonable time. For this novel technique the combination of fibre-friendly form closure and adhesive bonding of interface plays a major role. A well selected amount of vertical reinforcements, their placement and geometrical dimensions will lead to a stiffer joint. Goal is to minimize fibre-deletion and overlap length to improve load-transfer and joint-strength, to reduce weight in high-strength-applications as well as the avoidance of safety rivets.
Specific structural effects by strengthening pre-stressed concrete beams with externally bonded FRP
(2012)
Analysen auf NoSQL-Datenbanken sind oft langdauernd und die Ergebnisse fur den Benutzer haufig schwer verst ̈andlich. Wir prasentieren eine Möglichkeit, Datenmengen aus Wide-Column Stores mittels der Transformationssprache NotaQL zu transformieren sowie zu aggregieren und die Ergebnisse in Form von Diagrammen dem Benutzer darzustellen. Dabei kommen Sampling-Techniken zum Einsatz, um die Berechnung auf Kosten der Genauigkeit zu beschleunigen. Das von uns verwendete iterative Samplingverfahren sorgt fur eine kontinuierliche Verbesserung der Berechnungsgenauigkeit und bietet zudem Möglichkeiten zur Genauigkeitsabschätzung, die in Form von Konfidenzintervallen in den Diagrammen dargestellt werden kann.
In a recent study at the National Research Council Canada, the sound transmission in cold-formed steel-framed constructions was investigated. The results of direct sound insulation tests of wall and floor assemblies were reported at EURONOISE 2015 and INTERNOISE 2015. This paper focuses on flanking sound transmission in cold-formed steel-framed constructions. A representative full-scale mock-up specimen was constructed in NRC’s 8-room flanking transmission facility. The specimen consists of four loadbearing walls with 152 mm deep steel studs, four non-loadbearing walls with 92mm deep steel studs, and four floor-ceiling assemblies consisting of steel joists and a composite steel deck with gypsum concrete. Measurements were conducted according to the indirect method described in ISO 10848. The individual flanking paths were measured by a sequence of transmission loss measurements in which other transmission paths were suppressed by shielding. For the bare specimen without linings, the sound transmission for horizontally adjacent rooms with continuous subfloors is dominated by the floor-floor flanking paths. Floor coverings or floor toppings are needed to meet the requirements in the National Building Code of Canada. This paper presents details of the measurements, highlights some of the results and discusses implications.
While there are mature data models for exchanging semantically rich building models, no means for exchanging bridge models using a neutral data format exist so far. A major challenge lies in the fact that a bridge's geometry is often described in parametric terms, using geometric constraints and mathematical expressions to describe dependencies between different dimensions. Since the current draft of IFC-Bridge does not provide a parametric geometric description, this paper presents a possible extension and describes in detail the object-oriented data model proposed to capture parametric design including geometric and dimensional constraints. The feasibility of the concept has been verified by actually implementing the exchange of parametric models between two different computer-aided design (CAD) applications.
The cyclic deformation behavior of deep rolled and polished aluminium wrought alloy AlMg4,5Mn in the temperature range 20-300°C has been investigated. Results of quasistatic tension and compression tests of untreated specimens in the temperature range 20-300°C are presented. To characterize the fatigue behavior for stress-controlled tests as a function of test temperature, s-n curves, cyclic deformations curves and mean strains as a function of number of cycles are given. The residual stress- and work hardening states near the surface of deep rolled aluminium alloy AlMg4.5Mn before and after fatigue tests were investigated by X-ray diffraction methods. The investigated AlMn4.5Mn aluminium alloy shows cyclic hardening until fracture at all stress amplitudes in stress-controlled fatigue tests at 25-150°C. With increasing temperature the deformation behavior shifts from cyclic hardening to cyclic softening. Below a certain stress amplitude at a given temperature deep rolling led to a reduction of the plastic strain amplitude as compared to the untreated state through cyclically stable near-surface work hardening as indicated by stable FWHM-values. This reduction in plastic strain amplitude is associated with enhanced fatigue lives. The effectiveness of deep rolling is governed by the cyclic and thermal stability of near-surface work hardening rather than macroscopic compressive residual stresses. Since near-surface work hardening is known to retard crack initiation, deep rolling is also effective in temperature- and stress ranges where macroscopic compressive residual stresses have relaxed almost completely, but where near-surface work hardening prevails. Above certain stress amplitudes and temperatures, deep rolling has no beneficial effect on the fatigue behavior of AlMg4.5Mn. This is a consequence of instable near-surface microstructures, especially instable near-surface work hardening.
Defining infrastructural BIM standards is an essential issue to successfully implement BIM in the civil engineering domain and to gain acceptance of engineers, software developers and executive users. For this reason the paper proposes a way to improve collaboration between the geomechanical infrastructural design and analysis process, by introducing an infrastructural Information Delivery Manual (IDM). To realize IDM, the traditional geomechanical infrastructural use case was defined and the process specific workflow (activities & data exchange) was determined by developing an infrastructural process map. In order to ensure correct data exchange between the involved processes various Exchange Requirements (ER) were specified. But to the effect an infrastructural product model like IFC is still not available, the data exchange as well as the ER specification was made by different formats. At the end of this research activity the Model View Definition (MVD) was discussed.
The rising adoption of NoSQL technology in enterprises causes a heterogeneous landscape of different data stores. Different stores provide distinct advantages and disadvantages, making it necessary for enterprises to facilitate multiple systems for specific purposes. This resulting polyglot persistence is difficult to handle for developers since some data needs to be replicated and aggregated between different and within the same stores. Currently, there are no uniform tools to perform these data transformations since all stores feature different APIs and data models. In this paper, we present the transformation language NotaQL that allows cross-system data transformations. These transformations are output-oriented, meaning that the structure of a transformation script is similar to that of the output. Besides, we provide an aggregation-centric approach, which makes aggregation operations as easy as possible.
Wir pr asentieren SQL Island, ein neuartiges browserbasiertes Lernspiel,welches auf dem Konzept der Text-Adventures basiert. Nach einem Flugzeugabsturzlandet die Spielfigur auf einer Insel. Man redet mit Bewohnern, sammelt Gegenst ̈andeund k ̈apft gegen B ̈osewichte. Die Besonderheit bei diesem Spiel ist jedoch, dass derSpieler seine Figur lediglich mittels SQL-Befehlen steuert. Alle n ̈otigen Befehle wer-den zun ̈achst pr ̈asentiert, sodass keine Vorerfahrung notwendig ist. Nach etwa einerStunde Spielzeit beherrscht der Spieler SELECT-, UPDATE- und DELETE-Anfragensowie Gruppierungen, Aggregationsfunktionen und Joins. Das Spiel kann online aufhttp://www.sql-island.de kostenlos und ohne Registrierung gespielt werden.
Planning a new logistics center is a quite difficult job. Depending on the requirements there are a great number of possible design versions. The planner has to consider not only the present but also the future requirements. Up to now, the planner decides on the basis of experience which system will perform the requested services best. This paper illustrates the redesign of a new order-picking system in industry supported by a simulation tool of our institute designed especially for the rough planning. With the described project the road capability of the applied simulation concept is underlined. Several versions based on the requirements were investigated and evaluated. Key figures are calculated and a recommendation depending on performance and arising expenses is given.
Production supermarkets are a system to ensure high-frequency, demand-oriented, in-plant production supply with low lot sizes. The paper presents methods to design and dimension these systems using qualitative design criteria and quantitative approaches based on well-known analytical methods for conventional order picking systems. The methods help to design layout, provision type and path strategy and to derive space consumption and the number of supermarket employees required to fulfill a defined demand.
GroundXML: An addition of aligmnent and subsoil specific cross-sectional data to the LandXML scheme
(2009)
While high-level software components simplify the programming of grid applications and Web services increase their interoperability, developing such components and configuring the interconnecting services is a demanding task. In this paper, we consider the combination of Higher-Order Components (HOCs) with the Fractal component model and the ProActive library.
HOCs are parallel programming components, made accessible on the grid via Web services that use a special class loader enabling code mobility: executable code can be uploaded to a HOC, allowing one to customize the HOC. Fractal simplifies the composition of components and the ProActive library offers a generator for automatically creating Web services from components composed with Fractal, as long as all the parameters of these services have primitive types.
Taking all the advantages of HOCs, ProActive and Fractal together, the obvious conclusion is that composing HOCs using Fractal and automatically exposing them as Web services on the grid via ProActive minimizes the required efforts for building complex grid systems. In this context, we solved the problem of exchanging code-carrying parameters in automatically generated Web services by integrating the HOC class loading mechanism into the ProActive library.