57 research outputs found

    Statistical study on the link between real energy use, official energy performance and inhabitants of low energy houses

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    Energy performance regulations are becoming increasingly strict and governments supply simplified calculation tools to assess whether new buildings fulfil the requirements. However, one can wonder what the accuracy of those tools is for assessing the next generation of houses, that will have to fulfil the upcoming energy requirements. In order to investigate the discrepancy between predicted and real energy use in low energy houses, 537 dwellings were analysed. Data on building characteristics and theoretical energy use from the Flemish EPBD-database was complemented with data from the energy utilities and a survey of the inhabiting households, providing information about the households, their user behaviour and real energy use. While an undeniable correlation was found between theoretical and real energy use, the EPBD-method overestimated the heating energy use for most of the cases. Two building related parameters and two user related parameters proved to have a significant impact on that gap: the use of default values for the air tightness of the envelop and for the efficiency of the gas boiler, the heating profiles of the master bedrooms and the amount of baths and showers taken by the inhabitants. However, two comments must be made. First, the dataset consists of early adopters who could afford such energy performance years before it would be imposed and are therefore not representative of the average household. In addition, the analysis showed significant correlations between household characteristics on the one hand and building characteristics and performance on the other. These last two points question the possibility to extrapolate findings from samples of existing forerunners towards prognoses on future, entire building stock level

    A simulated annealing optimization of audio features for drum classification

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    Current methods for the accurate recognition of instruments within music are based on discriminative data descriptors. These are features of the music fragment that capture the characteristics of the audio and suppress details that are redundant for the problem at hand. The extraction of such features from an audio signal requires the user to set certain parameters. We propose a method for optimizing the parameters for a particular task on the basis of the Simulated Annealing algorithm and Support Vector Machine classification. We show that using an optimized set of audio features improves the recognition accuracy of drum sounds in music fragments

    Collecting ground truth annotations for drum detection in polyphonic music

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    In order to train and test algorithms that can automatically detect drum events in polyphonic music, ground truth data is needed. This paper describes a setup used for gathering manual annotations for 49 real-world music fragments containing different drum event types. Apart from the drum events, the beat was also annotated. The annotators were experienced drummers or percussionists. This paper is primarily aimed towards other drum detection researchers, but might also be of interest to others dealing with automatic music analysis, manual annotation and data gathering. Its purpose is threefold: providing annotation data for algorithm training and evaluation, describing a practical way of setting up a drum annotation task, and reporting issues that came up during the annotation sessions while at the same time providing some thoughts on important points that could be taken into account when setting up similar tasks in the future

    Reconstructing East African monsoon variability from grain-size distributions : end-member modeling and source attribution of diatom-rich sediments from Lake Chala

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    Grain-size analysis and end-member modeling of the clastic fraction of the 25-kyr sediment sequence from Lake Chala, a meromictic crater lake on the lower east slope of Mt. Kilimanjaro, reveal crucial aspects of climate-driven environmental change in equatorial East Africa since the Last Glacial Maximum. The finely laminated sediments of Lake Chala contain only up to 40% of clastic components, the rest are mainly diatom frustules and amorphous organic matter. Measured grain-size distributions were split into six statistically meaningful end members, of which four could be linked to a distinct source and transport mechanism of clastic mineral input: fine aeolian dust from distal sources (EM1), fine catchment runoff (EM2), coarser aeolian dust from proximal sources (EM5) and coarse erosive material from the upper crater slopes (EM6). The two other end members (EM3 and EM4) represented frustules of the two most common diatom taxa in Lake Chala, Afrocymbella barkeri and Nitzschia fabiennejansseniana, which had (partly) survived sample pre-treatment. Temporal variation in normalized abundance of the two dust-derived end members are valuable proxies for past changes in monsoon circulation over equatorial East Africa. During Northern Hemisphere cold periods (e.g., Last Glacial Maximum and Younger Dryas) the Inter-Tropical Convergence Zone shifted southward, enhancing northeasterly monsoon winds in the Lake Chala area and increasing advection of fine dust from the dry Horn of Africa region. Simultaneously, more modest continental heating reduced the prevalence of small-scale atmospheric turbulence, and thus the occurrence of dust devils, resulting in reduced influx of coarse dust from drylands nearby. Conversely, abrupt intensification of the southeasterly monsoon at the onset of the Holocene is recorded by an abrupt increase in the amount of coarse dust delivered to Lake Chala. Temporal variation in the end members representing catchment run-off (EM2) and erosion (EM6) mainly reflect changes in lacustrine sedimentation dynamics associated with major lake-level fluctuation, as evidenced by other paleoenvironmental proxies. Overall this study shows that subdivision of the clastic fraction of lacustrine sediments into statistically robust grain-size end members can provide multiple independent and quantitative proxies which help constrain reconstructions of a region’s multi-faceted climate history

    Current Directions in the Auricular Vagus Nerve Stimulation I – A Physiological Perspective

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    Electrical stimulation of the auricular vagus nerve (aVNS) is an emerging technology in the field of bioelectronic medicine with applications in therapy. Modulation of the afferent vagus nerve affects a large number of physiological processes and bodily states associated with information transfer between the brain and body. These include disease mitigating effects and sustainable therapeutic applications ranging from chronic pain diseases, neurodegenerative and metabolic ailments to inflammatory and cardiovascular diseases. Given the current evidence from experimental research in animal and clinical studies we discuss basic aVNS mechanisms and their potential clinical effects. Collectively, we provide a focused review on the physiological role of the vagus nerve and formulate a biology-driven rationale for aVNS. For the first time, two international workshops on aVNS have been held in Warsaw and Vienna in 2017 within the framework of EU COST Action “European network for innovative uses of EMFs in biomedical applications (BM1309).” Both workshops focused critically on the driving physiological mechanisms of aVNS, its experimental and clinical studies in animals and humans, in silico aVNS studies, technological advancements, and regulatory barriers. The results of the workshops are covered in two reviews, covering physiological and engineering aspects. The present review summarizes on physiological aspects – a discussion of engineering aspects is provided by our accompanying article (Kaniusas et al., 2019). Both reviews build a reasonable bridge from the rationale of aVNS as a therapeutic tool to current research lines, all of them being highly relevant for the promising aVNS technology to reach the patient

    Aerobic nonylphenol degradation and nitro-nonylphenol formation by microbial cultures from sediments

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    Nonylphenol (NP) is an estrogenic pollutant which is widely present in the aquatic environment. Biodegradation of NP can reduce the toxicological risk. In this study, aerobic biodegradation of NP in river sediment was investigated. The sediment used for the microcosm experiments was aged polluted with NP. The biodegradation of NP in the sediment occurred within 8 days with a lag phase of 2 days at 30°C. During the biodegradation, nitro-nonylphenol metabolites were formed, which were further degraded to unknown compounds. The attached nitro-group originated from the ammonium in the medium. Five subsequent transfers were performed from original sediment and yielded a final stable population. In this NP-degrading culture, the microorganisms possibly involved in the biotransformation of NP to nitro-nonylphenol were related to ammonium-oxidizing bacteria. Besides the degradation of NP via nitro-nonylphenol, bacteria related to phenol-degrading species, which degrade phenol via ring cleavage, are abundantly present
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