263 research outputs found
Nonparametric plug-in classifier for multiclass classification of S.D.E. paths
We study the multiclass classification problem where the features come from
the mixture of time-homogeneous diffusions. Specifically, the classes are
discriminated by their drift functions while the diffusion coefficient is
common to all classes and unknown. In this framework, we build a plug-in
classifier which relies on nonparametric estimators of the drift and diffusion
functions. We first establish the consistency of our classification procedure
under mild assumptions and then provide rates of cnvergence under different set
of assumptions. Finally, a numerical study supports our theoretical findings.Comment: 18 pages, 48 pages (including proofs and appendix), 2 figure
Apparent Densities of Stomoxys Species (Diptera, Muscidae) of Different Physiological Ages Caught with Vavoua Trap Differ With Landscape and Trapping Period
Stable flies (Stomoxys spp.) are common pests of livestock in the peri-urban rangelands of Vina Division of the Adamawa Plateau. No documented information is available on their diurnal dynamics in relation to physiological age and landscape. The main aim of this study was to determine the trap apparent density (ADT) of Stomoxys and associate it to their diurnal activity rhythm and landscape. Vavoua traps (n=12) were used for Stomoxys collection. Trapping was carried out for seven days i.e. three days consecutively in August and four days consecutively in October, 2016.Three traps were pitched in each of the three biotopes (river, cattle corral and gallery forest) of the four study sites (Galim, Mbidjoro, Velambai and Soukourwo). All female Stomoxys captured underwent ovarian dissection for the determination of their physiological ages (parous or nulliparous). A total of 218 Stomoxys were caught and identified into four species (S. niger niger, S. omega, S. calcitrans, and S.xanthomelas) with an overall ADT of 2.59 flies per trap per day and Stomoxys niger niger (1.13 s.n.n. per trap per day) recorded the highest ADT. Species richness was study site dependent.Higher catches of females 113 (51.83%) were made than that of their male 105 (48.17%) counterparts. Galim recorded the highest Stomoxys apparent density (4.90) as compared to other sites with a statistically significant difference (P<0.05). The proportion of parous 87 (59.30%) was higher than that of their nulliparous 46 (40.71%) counterparts. Parity differed with landscape and capture periods. S. n. niger was the most frequent in all biotopes and Galim recorded the highest ADT. The population of female flies was made up of adults (parous) with a bimodal diurnal activity rhythm whereas males had a unimodal activity rhythm.
Evaluation of the role of Guenons and Mangabeys in seed dispersal in Moukalaba-Doudou National Park, Gabon
In order to gain knowledge on the quantity of seed dispersed and the contribution of small diurnal primates in the ecosystem, a preliminary study on four species of monkeys was carried out in the northeastern part of the Moukalaba-Doudou National Park in Gabon. The aim was to identify the species of fruits which are dispersed and the animal biomass in two large groups of monkeys namely mangabeys (Cercocebus torquatus and Lophocebus albigena) and guenons (Cercopithecus cephus and Cercopithecus nictitans). Using the reconnaissance walking method, we followed old tracks and dung piles were collected after direct observation of the little monkeys and in the sleeping site. The dung piles were washed, and the seeds collected were identified. A total of 104 fecal samples from the four species of monkeys were collected. Seeds from 19 species of plants were found in the dung piles. The majority of the seeds found in droppings were seeds of Cissus dinklagei and Musanga cecropioides. Cercopithecus nictitans dispersed seeds of more plant species than the others. All the results obtained show that the monkeys disperse an average of 1,114 seeds per day. In this study guenons disperses more fruit than the mangabeys who have a more varied diet. These results suggest that monkeys of Moukalaba-Doudou disperse fewer seeds compared to monkeys in other sites in Africa.
Afin d’avoir une connaissance sur la quantité de graine dispersée et la contribution des petits primates diurnes dans l’écosystème, une étude préliminaire sur quatre espèces de singes a été réalisée dans la partie nord-est du Parc National de Moukalaba-Doudou au Gabon. L’objectif était de connaître les espèces de fruits dispersées et la biomasse animale chez deux grands groupes de singes à savoir les mangabeys (Cercocebus torquatus et Lophocebus albigena) et les guenons (Cercopithecus cephus et Cercopithecus nictitans). En utilisant la méthode de la marche de reconnaissance, nous avons suivi d’anciennes pistes et les tas de fumier ont été ramassés après observation directe des petits singes et dans les dortoirs. Les crottes ont été lavées et les graines récoltées ont été identifiées. Un total de 104 échantillons fécaux des quatre espèces de singes a été collectés. Les graines de 19 espèces de plantes ont été trouvées dans les excréments. Cercopithecus nictitans a dispersé plus d’espèces de graines que les autres. La majorité des graines trouvées dans les déjections étaient des graines de Cissus dinklagei et Musanga cecropioides. L’ensemble des résultats obtenus montre que les singes dispersent en moyenne 1114 graines par jour. Dans cette étude les guenons dispersent plus de fruits que les mangabeys qui ont une alimentation plus variée. Ces résultats suggèrent que les singes de Moukalaba-Doudou dispersent peu de graines en comparaison aux singes d’autres sites en Afrique. 
Simulation analysis of an innovative micro-solar 2kWe Organic Rankine Cycle plant coupled with a multi-apartments building for domestic hot water supply
Combined heat and power plants driven by renewable energy sources (RES) are becoming more and more popular, given the energy transition towards the integration of more renewable energy sources in the power generation mix. In this paper an innovative micro-solar 2kWe/18kWth Organic Rankine Cycle system, which is being developed by the consortium of several Universities and industrial organizations, with the funding from EU under the Innova MicroSolar project, is considered. In particular, its application to supply electricity and thermal energy for Domestic Hot Water (DHW) in a residential building is investigated by means of simulation analysis. Different Domestic Hot Water supply plant configurations are evaluated and the design parameters are varied in order to determine the best configuration to recover as much energy as possible from the ORC, while maintaining the final users’ comfort. It was found out that with the considered plant around 67% of the Domestic Hot Water energy demand of 15 apartments can be satisfied with a water storage tank of 10’000 liters. However, in order to always guarantee the supply water temperature, a back-up boiler, which serves directly the final users when needed, is requested
Development of a small solar thermal power plant for heat and power supply to domestic and small business buildings
The small solar thermal power plant is being developed with funding from EU Horizon 2020 Program. The plant is configured around a 2-kWel Organic Rankine Cycle turbine and solar field, made of Fresnel mirrors. The solar field is used to heat thermal oil to the temperature of about 240°C. This thermal energy is used to run the Organic Rankine Cycle turbine and the heat rejected in its condenser (about 18-kWth) is utilised for hot water production and living space heating.
The plant is equipped with a latent heat thermal storage to extend its operation by about 4 hours during the evening building occupancy period. The phase change material used is Solar salt with the melting/solidification point at about 220°C. The total mass of the PCM is about 3,800kg and the thermal storage capacity is about 100kWh. The operation of the plant is monitored by a central controller unit. The main components of the plant are being manufactured and laboratory tested with the aim to assemble the plant at the demonstration site, located in Catalonia, Spain. At the first stage of investigations the ORC turbine will be directly integrated with the solar field to evaluate their joint performance. During the second stage of tests, the Latent Heat Thermal Storage will be incorporated into the plant and its performance during the charging and discharging processes will be investigated. It is planned that the continuous field tests of the whole plant will be performed during the 2018-2019 period
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