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van Diest M.,INCAS | van Diest M.,University of Groningen | Stegenga J.,INCAS | Wortche H.J.,INCAS | And 4 more authors.
Gait and Posture | Year: 2016

Exercise videogames (exergames) are gaining popularity as tools for improving balance ability in older adults, yet few exergames are suitable for home-based use. The purpose of the current pilot study was to examine the effects of a 6-week unsupervised home-based exergaming training program on balance performance. Ten community dwelling healthy older adults (age: 75.9 ± 7.2 years) played a newly developed ice skating exergame for six weeks at home. In the game, the speed and direction of a virtual ice skater on a frozen canal were controlled using lateral weight shifts, which were captured using Kinect. Sway characteristics during quiet standing in eyes open (EO), eyes closed (EC) and dual task (DT) conditions were assessed in time and frequency domain before, and after two, four and six weeks of training. Balance was also evaluated using the narrow ridge balance test (NRBT). Multilevel modeling was applied to examine changes in balance ability. Participants played 631 (±124) min over the intervention period and no subjects dropped out. Balance in terms of sway characteristics improved on average by 17.4% (EO) and 23.3% (EC) after six weeks of training (p < 0.05). Differences in rate of improvement (p < 0.05) were observed between participants. No intervention effects were found for quiet standing in DT conditions and on the NRBT. In conclusion, the pilot study showed that unsupervised home-based exergaming is feasible in community dwelling older adults, but also that participants do not benefit equally from the program, thereby emphasizing the need for more personalized exergame training programs. © 2015 Elsevier B.V..

Georgescu C.,University of Galati | Deleanu L.,University of Galati | Pirvu C.,InCaS
IOP Conference Series: Materials Science and Engineering | Year: 2016

Due to improvement in analysing surface texture and optical instruments for investigating the texture surface, the authors propose to evaluate the lubricant performance by analysing the change in several 3D parameters in comparison to an analysis on 2D profile. All the surface of the wear scar generated on the four ball machine is investigated and the conclusion is that from the tribological point of view, the 3D parameters reflect better the surface quality evolution after testing. Investigation was done on the wear scars generated on the three fixed balls, for five lubricants: a non-additivated transmission mineral oil (T90), two grades of rapeseed oil (coarse degummed and refined) and two grades of soybean oil (coarse and degummed). © Published under licence by IOP Publishing Ltd.

Iacca G.,INCAS | Caraffini F.,De Montfort University | Caraffini F.,University of Jyväskylä | Neri F.,De Montfort University | Neri F.,University of Jyväskylä
Proceedings - 2015 IEEE Symposium Series on Computational Intelligence, SSCI 2015 | Year: 2015

Ensemble of parameters and mutation strategies differential evolution (EPSDE) is an elegant promising optimization framework based on the idea that a pool of mutation and crossover strategies along, with associated pools of parameter settings, can flexibly adapt to a large variety of problems when a simple success based rule is introduced. Modern versions of this scheme successfully attempts to improve upon the original performance at the cost of a high complexity. One of most successful implementations of this algorithmic scheme is the Self-Adaptive Ensemble of Parameters and Strategies Differential Evolution (SaEPSDE). This paper operates on the SaEPSDE, reducing its complexity by identifying some algorithmic components that we experimentally show as possibly unnecessary. The result of this de-constructing operation is a novel algorithm implementation, here referred to as "j" Ensemble of Strategies Differential Evolution (jESDE). The proposed implementation is drastically simpler than SaEPSDE as several parts of it have been removed or simplified. Nonetheless, jESDE appears to display a competitive performance, on diverse problems throughout various dimensionality values, with respect to the original EPSDE algorithm, as well as to SaEPSDE and three modern algorithms based on Differential Evolution. © 2015 IEEE.

Comrie A.C.,University of Cape Town | Buffler A.,University of Cape Town | Smit F.D.,IThemba LABS | Wortche H.J.,INCAS
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2015

Three different digital implementations of pulse shape discrimination for pulses from an EJ301 liquid scintillator detector are presented, and illustrated with neutrons and gamma-rays produced by an Am-Be radioisotopic source, a D-T generator and beams produced by cyclotron-accelerated protons of energies 42, 62 and 100 MeV on a Li target. A critical comparison between the three methods is provided. © 2014 Elsevier B.V. All rights reserved.

Bosman H.H.W.J.,TU Eindhoven | Iacca G.,TU Eindhoven | Wortche H.J.,INCAS | Liotta A.,INCAS
IEEE International Conference on Data Mining Workshops, ICDMW | Year: 2015

Ever-more ubiquitous embedded systems provide us with large amounts of data. Performing analysis close to the data source allows for data reduction while giving information when unexpected behavior (i.e. Anomalies in the system under observation) occurs. This work presents a novel approach to online anomaly detection, based on an ensemble of classifiers that can be executed on distributed embedded systems. We consider both single and multi-dimensional input classifiers that are based on prediction errors. Predictions of single-dimensional time series input come from either a linear function model or general statistics over a data window. Multi-dimensional input stems from current and historical sensor values as well as predictions. We combine the classifier outputs in the ensemble using a heuristic method and Fisher's combined probability test. The proposed framework is tested thoroughly using synthetic and real-world data. The results are compared to known methods for anomaly detection on limited-resource systems. While individual classifiers perform comparably to known methods, our results show that using an ensemble of classifiers increases the overall detection of anomalies considerably. © 2014 IEEE.

Wang Y.,Wageningen University | Bakker F.,INCAS | de Groot R.,Wageningen University | Wortche H.,INCAS
Building and Environment | Year: 2014

The influence of urban green infrastructure on the indoor environment and the effects on human comfort and economic consequences are still unclear. This paper gives a systematic overview of the relationship, in terms of so-called 'ecosystem services', between urban green infrastructure and the indoor environment through a literature review in different disciplines. Urban green infrastructure (mainly trees, green walls and roofs) was found to contribute, both positively and negatively, to the indoor environment via the influence on the climate, energy use, air quality, sonic environment and aesthetic quality. Four main factors that influence these effects were identified, being vegetation characteristics, building characteristics (including layout and geometry), and geographical conditions. Although the reviewed papers have investigated the different ecosystem services on a wide range of space and time scales, the performance of urban green on the meso- and macro climate has received less attention than on the micro scale. Also direct effects of urban green infrastructure on indoor air quality and sonic environment were rarely studied. Another finding is that, whereas the modelling approach on climate regulation has been widely adopted by researchers throughout the world, empirical studies have mainly been performed in the USA. We also analysed the data found on economic implications. The economic effects of adjoining vegetation and green roofs on climate regulation provided energy savings of up to almost $250/tree/year, while the air quality regulation was valued between $0.12 and $0.6/m2 tree cover/year. Maximum monetary values attributed to noise regulation and aesthetic appreciation of urban green were $20 - $25/person/year, respectively. Of course these values are extremely time- and context-dependent but do give an indication of the potential economic effects of investing in urban green infrastructure. Based on this review, we conclude that new methods, measurement instruments and field experiments are needed to improve empirically supported correlations and develop concrete recommendations for urban planning and design. © 2014 Elsevier Ltd.

Zaharovits A.,Polytechnic University of Bucharest | Stegaru S.,Polytechnic University of Bucharest | Carabas M.,Polytechnic University of Bucharest | Slusanscrn E.-I.,Polytechnic University of Bucharest | Pricop M.-V.,INCAS
2015 14th RoEduNet International Conference - Networking in Education and Research, RoEduNet NER 2015 - Proceedings | Year: 2015

This paper aims to study and improve the runtime of a topology optimization scientific code named OPTRUSS (OPTimization of TRUSS structures), developed at the Romanian National Institute for Aerospace Research 'Elie Carafoli'. OPTRUSS is a FORTRAN code that optimizes the stiffness of truss structure, minimizing compliance, following the SIMP algorithm. The physical problem solved is relevant because of the linear system's assembled stiffness sparse matrix - emphasis on sparse. The primary metric for performance is the average Wall Time per iteration of the Conjugate Gradient algorithm, and we will focus on evaluating the speedup of the proposed OpenMP and CUDA parallelizations. © 2015 IEEE.

Vasiliu G.C.,Polytechnic University of Bucharest | Vasiliu D.,Polytechnic University of Bucharest | Vasiliu N.,Polytechnic University of Bucharest | Ion Guta D.,INCAS
UPB Scientific Bulletin, Series D: Mechanical Engineering | Year: 2014

The paper presents the mathematical modeling, and the numerical simulation of the dynamics of a swashplate servopump with mechanical feedback. The servomechanism controlling the pump displacement is supplied by a low pressure gear pump, and includes oversized pistons for rejecting the high frequency tilting force. The response time is controlled by the diameter of a metering orifice sited on the supply port. The theoretical performance of the servopump is found in good agreement with the manufacturer specifications.

Gholaminezhad I.,Guilan University | Iacca G.,INCAS
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

This paper describes a new evolutionary algorithm for multiobjective optimization, namely Multi-Objective Relative Clustering Genetic Algorithm (MO-RCGA), inspired by concepts borrowed from gene relatedness and kin selection theory. The proposed algorithm clusters the population into different families based on individual kinship, and adaptively chooses suitable individuals for reproduction. The idea is to use the information on the position of the individuals in the search space provided by such clustering schema to enhance the convergence rate of the algorithm, as well as improve its exploration. The proposed algorithm is tested on ten unconstrained benchmark functions proposed for the special session and competition on multi-objective optimizers held at IEEE CEC 2009. The Inverted Generational Distance (IGD) is used to assess the performance of the proposed algorithm, in comparison with the IGD obtained by state-of-the-art algorithms on the same benchmark. © Springer-Verlag Berlin Heidelberg 2014.

Hao Y.,University of Sheffield | Kang J.,University of Sheffield | Krijnders J.D.,INCAS
Landscape and Urban Planning | Year: 2015

The aim of this study is to determine how to increase birdsong loudness and the visibility of green areas in low-density residential areas by controlling urban morphological parameters. The spatial sound level distributions of birdsong at 12 sites sampled from a GIS database of Assen, the Netherlands, were simulated by noise mapping techniques and calculated using a MATLAB program on spatial sound level matrices. The visibilities of green areas are analysed and calculated by Visibility Analysis Graph in Space Syntax. Correlation analyses were conducted between the obtained data on spatial sound level indices, the mean visibility and urban morphological parameters. The results show that birdsong loudness has significant positive linear relationships with urban morphological parameters, including Building Plan Area Fraction (R2=0.491), Green Area Perimeters (R2=0.491) and Green Area Dispersion Index (R2=0.618), while the visibility of green area has negative linear relationships with morphological parameters, including Building Plan Area Fraction (R2=0.431) and Green Area Perimeters (R2=0.799). It has also been found that in the proximity of green areas, the visibility of green areas has a positive relationship with birdsong loudness, whereas in most areas further from green areas, the visibility of green areas has a negative relationship with birdsong loudness. Either increasing birdsong loudness or enhancing visibility of the green areas by controlling urban morphological parameters is helpful for the optimisation of soundscape design with masking effects. Bird habitats and vegetation are important ecological issues to consider for the enhancement of the roles of urban morphology. © 2015 Elsevier B.V.

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