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In recent years, Virtual Reality (VR) has become a powerful tool in studies involving perceptual evaluation of auralization methods. The aim of this study was to investigate the extent to which binaural auralizations from a wave-based method are perceptually close to those from measurements for two different room acoustical scenarios. The signals used for auralization are simulated using the Discontinuous Galerkin method. The simulations encompass geometric details of the room, material properties of the objects in the room and receiver directivity including head orientation. The measured Binaural Room Impulse Responses (BRIRs) were limited to an upper frequency of 2.5 kHz to match the bandwidth of the simulations. The reverberation time results show a fairly good agreement between the measured and simulated data, thereby indicating that the wave-based method can be held as a reference for achieving perceptually realistic auralizations. To evaluate this, a listening experiment was carried out in an interactive VR environment employing a 3D model of the room integrating a dynamic convolution framework with headphone reproduction. The BRIRs were convolved in real-time with two types of source signal – percussion and female voice speech. Twelve normal hearing participants performed a rating task for judging differences between measured and simulated BRIRs for four perceptual attributes - reverberance, clarity, bassiness and externalization. The results indicate that the mean difference between measurement and simulation is statistically significant for reverberance, clarity and bassiness but not for externalization. Additionally, this study highlights a state-of-the-art experimental framework which can be used for perceptual evaluation studies independent of the computational method used to derive the auralizations.

In the context of quality evaluation of reproduced sound, it is unknown if existing sensory evaluation methods for stationary spatial sound conditions would also work when sound sources or listeners move during the formation of a quality judgement in the listener’s mind. To investigate this problem, we review literature in the fields of sound quality evaluation and dynamic sensory evaluation. We also describe specific methodologies for the temporal assessment of food quality and present them as potential candidates for spatially dynamic sound quality evaluation. Finally, we discuss the results of a pilot experiment where we implemented the Temporal-Check-All-That-Apply (TCATA) methodology to evaluate the sound quality of spatially dynamic sound stimuli.

This report presents the process, findings and user-guide of the development of a real time Virtual Reality with Auralization system allowing building-designers, owners and end-users to listen to a design proposal and provide such people a better foundation for decision-making and a heightened ability to consider the acoustic IE during building design.

This paper describes the development and initial testing of a Virtual Reality withAuralization system. To facilitate a realistic auralization, sound sources wererecorded in an anechoic room and inserted into a test scenario. The scenario waspresented to test persons in order to evaluate the realism of the system, andprovide feed-back ahead of further development.

Forecasting accuracy in context of fresh meat products with short shelf life is studied. Main findings are that forecasting accuracy measures (i.e. errors) should penalize deviations differently according to product characteristics, mainly dependent on whether the deviation is large or small, negative or positive. This study proposes a decision-based mean hybrid evaluation which penalize deviations according to type of animal, demand type, product life cycle and product criticality, i.e. shelf life, inventory level and future demand.

Promotions at retailers are an effective marketing instrument, driving customers to stores, but their demand is particularly challenging to forecast due to limited historical data. Previous studies have proposed and evaluated different promotion forecasting methods at product level, such as linear regression methods and random trees. However, there is a lack of unified overview of the performance of the different methods due to differences in modeling choices and evaluation conditions across the literature. This paper adds to the methods the class of emerging techniques, based on ensembles of decision trees, and provides a comprehensive comparison of different methods on data from a Danish discount grocery chain for forecasting chain-level daily product demand during promotions with a four-week horizon. The evaluation shows that ensembles of decision trees are more accurate than methods such as penalized linear regression and regression trees, and that the ensembles of decision trees benefit from pooling and feature engineering.

In the sandbox world of cyber-physical systems and internet-of-things a number of applications is only eclipsed by a number of products that provide solutions for specific problem or set of problems. Initiatives like the European project EMC2 serve as cross-disciplinary incubators for novel technologies and fuse them together with state-of-the-art industrial applications. This paper reflects on challenges in scope of hardware architectures and related technologies. It also provides a short overview of several technologies explored in the project that provide bridging solutions for these problems.

Hvert år sker der adskillige uheld, hvor højresvingende lastbiler rammer cyklister, der kører ligeud. Mange tiltag har haft fokus på at forbedre lastbilchaufførens evne til visuelt at spotte cyklisterne, hvilket har resulteret i, at chaufføren er blevet overbebyrdet med for mange visuelle input. I denne artikel forsøges der i stedet at hjælpe lastbilchaufføren ved at repræsentere cyklisten ved hjælp af 3D-lyd, og dermed give lastbilchaufføren en indikation af cyklistens placering. I et feltstudie, hvor fire chauffører kørte på deres daglige rute, blev en eksperimentel platform brugt til at give lastbilchaufføren auditiv information om cyklistens placering, hver gang en cyklist nærmede sig lastbilen. Lastbilchaufførerne gav udtryk for, at systemet var en hjælp, og at de forholdsvis let kunne bruge lyden til at følge cyklisten undervejs., Selected Proceedings from the Annual Transport Conference at Aalborg University, Årg. 11 Nr. 1 (2016): Selected Proceedings from the Annual Transport Conference at Aalborg University

The perceptual differences between the sound reproductions of headphones were investigated in a pair-wise comparison study. Two musical excerpts were reproduced over 21 headphones positioned on a mannequin and recorded. The recordings were then processed and reproduced over one set of headphones to listeners, who were asked to evaluate their perceived degree of dissimilarity. The two musical excerpts were used in separate experiments. The processing of the recordings consisted of compensating for the influences of the playback headphones worn by the listeners as well as for the mannequin's ear canals. A multidimensional scaling analysis revealed two dominating perceptual dimensions used by the listeners to differentiate the reproductions of the headphones. These dimensions were similar for the two musical excerpts. Objective metrics are proposed to describe them, leading to correlations ranging from 0.89 to 0.97 between the dimensions and metrics. The first perceptual dimension was associated with the relative strength of bass, while the second dimension was related to the relative strength of the lower midrange. The perceptual differences between the sound reproductions of headphones were investigated in a pair-wise comparison study. Two musical excerpts were reproduced over 21 headphones positioned on a mannequin and recorded. The recordings were then processed and reproduced over one set of headphones to listeners, who were asked to evaluate their perceived degree of dissimilarity. The two musical excerpts were used in separate experiments. The processing of the recordings consisted of compensating for the influences of the playback headphones worn by the listeners as well as for the mannequin's ear canals. A multidimensional scaling analysis revealed two dominating perceptual dimensions used by the listeners to differentiate the reproductions of the headphones. These dimensions were similar for the two musical excerpts. Objective metrics are proposed to describe them, leading to correlations ranging from 0.89 to 0.97 between the dimensions and metrics. The first perceptual dimension was associated with the relative strength of bass, while the second dimension was related to the relative strength of the lower midrange.

In this study the characteristics of compact loudspeakers in a stereo setup were investigated. Perceptual evaluations of eleven loudspeakers were conducted on the basis of six selected sensory descriptors, chosen by experienced listeners during consensus meetings. Based on an analysis of the perceptual evaluation, four of the descriptors were found suited for modelling, with the purpose of developing metrics for prediction of Bass depth, Punch, Brilliance, and Dark-Bright. Bass depth and Punch were modelled as one due to high correlation between them. The experimental setup included loudspeaker spinners, enabling fast positioning of loudspeakers. The prediction models were based on binaural recordings, processed using a loudness model, and developed on the basis of previous work on headphone modelling [1, 2]. They were trained on a subset of the data (66%) and validated on the rest. The resulting metrics had high correlations with the perceptual ratings of the validation dataset (r = 0.87-0.96).

The aspects of what provides a good user experience with headphones is initially investigated by an exploratory study (experiment I). Using KJ-Technique, 5 workshop teams of 4-6 participants each provide a number of aspects influencing their experience with headphones. Analysing the aspects for uniqueness and relatedness provides 144 aspects of user experience with headphones, arranged in 12 categories. The 144 influencing aspects from experiment I are condensed, and 24 attributes regarding user experience with headphones are selected. These attributes are tested in regard to their correlation with and effects on overall evaluation of headphones in a second experiment, thus investigating which attributes are most influential for user experience. Using a within-subject design, eight different headphones are evaluated according to the attributes along with an overall evaluation. The attributes are listed in the following categories: sound quality, comfort, build quality, design and brand. A factor analysis shows that the categories fit the attributes. Furthermore, some attributes show high correlations with the overall evaluation, suggesting that these attributes are important for user experience with headphones. The highest rated attributes are shape, design, quality of contact surfaces, comfort, goodness of fit and build quality. An interpretation of which attributes are the most influential in relation to user experience with headphones is discussed.

This report is a documentation of the calibration procedure, and the present state of calibration of the low frequency sound level meter “Lavfrekvens lydmåler” (LFLM). The LFLM system is a sound level meter developed to measure calibrated LpA,LF values at remote positions (houses) by the occupants. The LFLM is calibrated in a special developed LF calibrator. Then it is sent to the remote user. Sound recordings are made and the LFLM is then connected to wired Ethernet and the recordings are automatically uploaded to an AAU server. The recordings are then analyzed with Matlab programs to deliver a results sheet of the measurement. The calculations of LpA,LF are based on 1/3 octave band analysis of the recorded sound. The calculations of LpA,LF are documented. The 1/3 octave filter bank is measured, and shown to be within the strict IEC 1260:1995 Class 0 limits, and the A-weighting function is concluded to comply with DS/EN 61672-1:2014 class 1. The calibration of LFLM is done at the 1/3 octave center frequencies between 10 and 160 Hz, and it is shown to be within +0.34 ; -0.32 dB of the nominal 94 dB value. This is based on an adjustment of the LF calibrator from June 2014 so any drift of the LF calibrator since then is included in the result. This report is a documentation of the calibration procedure, and the present state of calibration of the low frequency sound level meter “Lavfrekvens lydmåler” (LFLM). The LFLM system is a sound level meter developed to measure calibrated LpA,LF values at remote positions (houses) by the occupants. The LFLM is calibrated in a special developed LF calibrator. Then it is sent to the remote user. Sound recordings are made and the LFLM is then connected to wired Ethernet and the recordings are automatically uploaded to an AAU server. The recordings are then analyzed with Matlab programs to deliver a results sheet of the measurement. The calculations of LpA,LF are based on 1/3 octave band analysis of the recorded sound. The calculations of LpA,LF are documented. The 1/3 octave filter bank is measured, and shown to be within the strict IEC 1260:1995 Class 0 limits, and the A-weighting function is concluded to comply with DS/EN 61672-1:2014 class 1. The calibration of LFLM is done at the 1/3 octave center frequencies between 10 and 160 Hz, and it is shown to be within +0.34 ; -0.32 dB of the nominal 94 dB value. This is based on an adjustment of the LF calibrator from June 2014 so any drift of the LF calibrator since then is included in the result.