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Noisy: Identification of problematic columns in multiple sequence alignmentsDress, Andreas W.M., Flamm, Christoph, Fritzsch, Guido, Grünewald, Stefan, Kruspe, Matthias, Prohaska, Sonja J., Stadler, Peter F. 13 December 2018 (has links)
Motivation
Sequence-based methods for phylogenetic reconstruction from (nucleic acid) sequence data are notoriously plagued by two effects: homoplasies and alignment errors. Large evolutionary distances imply a large number of homoplastic sites. As most protein-coding genes show dramatic variations in substitution rates that are not uncorrelated across the sequence, this often leads to a patchwork pattern of (i) phylogenetically informative and (ii) effectively randomized regions. In highly variable regions, furthermore, alignment errors accumulate resulting in sometimes misleading signals in phylogenetic reconstruction.
Results
We present here a method that, based on assessing the distribution of character states along a cyclic ordering of the taxa, allows the identification of phylogenetically uninformative homoplastic sites in a multiple sequence alignment. Removal of these sites appears to improve the performance of phylogenetic reconstruction algorithms as measured by various indices of 'tree quality'. In particular, we obtain more stable trees due to the exclusion of phylogenetically incompatible sites that most likely represent strongly randomized characters.
Software
The computer program noisy implements this approach. It can be employed to improving phylogenetic reconstruction capability with quite a considerable success rate whenever (1) the average bootstrap support obtained from the original alignment is low, and (2) there are sufficiently many taxa in the data set – at least, say, 12 to 15 taxa. The software can be obtained under the GNU Public License from http://www.bioinf.uni-leipzig.de/Software/noisy/.
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Estudo da distribuição de temperaturas em ambientes condicionados por evaporador hi wall / Numerical study of temperature characteristics in a mini spli Air-conditioning SystemsRibeiro, Caio Augusto Garcia 11 June 2018 (has links)
Submitted by Caio Augusto Garcia Ribeiro (cabecapequena@gmail.com) on 2018-08-02T00:52:57Z
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Previous issue date: 2018-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O ar-condicionado tem-se tornado um dos grandes responsáveis pelo aumento da demanda de energia elétrica no Brasil e no mundo, pois com o desenvolvimento econômico combinado a redução de preço dos equipamentos de ar-condicionados, mais residências e comércios os utilizam em busca de conforto térmico. Mas o uso pode acarretar em um aumento considerável na conta de energia, já que o ar-condicionado é o aparelho doméstico com alto consumo de energia. A solução imediata apontada por Sivak (2009) e Shan et al. (2013) para que o crescimento do uso de arcondicionado não provoque uma crise energética no mundo seria desenvolver aparelhos com a mesma qualidade de refrigeração dos atuais, mas que consumiriam bem menos energia. O aparelho mais utilizado em residências, pequenos comércios e escritórios, é o split system, com o evaporador do tipo Hi-wall, equipamento que tem algumas limitações em relação a sua distribuição de ar, que provoca bolsões de ar quente e frio no mesmo ambiente, além de provocar desconfortos localizados. O controle desse evaporador é baseado na temperatura de retorno, ou seja, se a temperatura no retorno não atingir a temperatura estabelecida o mesmo opera em sua potência máxima por um tempo maior que o necessário, desperdiçando assim energia elétrica, ou a temperatura pode ser alcançada antes no retorno do que no ambiente, provocando assim desconforto térmico por mais tempo. Assim, será proposta neste trabalho uma solução numérica, utilizando um código CFD, a partir das equações diferencias de energia combinada com as equações de Navier–Stokes, em um modelo turbulento semi empírico k-epsilon de duas equações, considerando as três dimensões. Partindo de um caso padrão foram outros 11 casos alterando a altura do evaporador e o ângulo de insuflamento. Com os resultados pôde-se avaliar qual dos 11 casos foi mais eficiente do ponto de vista energético o qual produz melhor conforto térmico, para assim avaliar melhorias que podem ser aplicadas no evaporador hi-wall. / Air conditioning has become one of the main factors responsible for the increase in the electric demand in Brazil and in the world, since with economic development combined with the price reduction of air conditioning equipment, more residences and businesses use them to reach thermal comfort. But the use can lead to a considerable increase in the energy bill, since air conditioning is the household appliance with a high energy consumption. The immediate solution pointed out by Sivak (2009) and Shah et al. (2013), so that the growth of the use of air conditioning does not cause an energy crisis in the world, would be to develop devices with the same quality of refrigeration of the present, but that would consume much less energy. The most commonly devices used in residence, small shops and offices, are Split System, whit a high wall as internal unit, this evaporator has some limitations in the air distribution, which causes hot and cold zones in the same environment, as well as causing localized discomfort. The evaporator control is based on the return temperature, so if the return temperature does not reach the set temperature, the Air Conditioner will operate at its maximum power for a time longer than necessary, thus wasting electrical energy or the set temperature can be reached before in the evaporator than in the environment, thus causing thermal discomfort for longer. Thus, a numerical solution, using a CFD code, will be proposed using the energy-difference equations combined with the Navier-Stokes equations, considering a turbulent flow based in a semi-empirical k-epsilon turbulent model of two equations, considering the three dimensions. And using a model as standard, another 11 models were simulated by changing the height of the evaporator and the angle of inflation. With the results, it can be evaluated which of the 12 cases is more energy efficient and which causes better thermal comfort. And than identify improvements that can be applied in hi-wall units.
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IMPACT OF HIGH-EFFICIENCY AND VARIABLE-SPEED MOTORS ON THE PERFORMANCE OF A RESIDENTIAL SPLIT-SYSTEM HEAT PUMPJohn Kevin Brehm (13104168) 15 July 2022 (has links)
<p>In the current marketplace, most ducted split-system heat pumps feature single-speed compressors and fans. To meet forthcoming minimum energy rating requirements, reduce operational costs, and increase environmental sustainability, the seasonal heating and cooling efficiencies of heat pump systems must be improved. Variable-speed equipment offers significant advantages for load modulation and has the ability to increase the seasonal performance greatly. Additionally, novel electrical motor technologies, such as permanent magnet (PM) motors, can reduce the power consumption of the motors by up to 25-55% compared to the widely used permanent split capacitor (PSC) motor or electronically commutated motor (ECM). In this study, a low cost ducted single-speed heat pump system with a cooling capacity of 10.55 kW was analyzed to quantify the impact of fan and compressor motor efficiency on seasonal coefficient of performance (SCOP). Furthermore, single-speed components were replaced with variable to evaluate the performance increase. The single-speed heat pump was experimentally tested, and the results were used to tune a detailed model for further performance analyses. The efficiency was evaluated in heating and cooling mode according to AHRI Standard 210/240 and with an energy savings and cost analysis, that details the SCOP and costs for different locations. The conversion of the fan motors to high efficiency PM magnet motors increased the SCOP by up to 6%. The impact was dependent on the initial motor efficiency and the operational mode. The indoor unit fan motor has a large impact on SCOP in cooling mode and a low impact in heating mode because of the motor waste heat’s impact on capacity. The conversion to a fully variablespeed system greatly increased the performance, with a 72% increase in cooling SCOP and a 19% increase in heating SCOP. The energy savings and cost analysis concluded that the fan motor conversion from single-speed to high efficiency motors is economically viable, but the financial benefit of the upgrade to variable-speed depends on the intended location of use. </p>
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Klimatizace učeben a kanceláří / Air-conditioning of lecture rooms and officesBečvář, Jaroslav January 2008 (has links)
The diploma thesis is consisting of two parts. Forepart is a theoretic survey. It construes basic office of the air conditioning and deal with used air conditioner arrangements. More deeply it deals with air conditioner systems with refrigerant and the air conditioning for electronic equipments. Project of split system for air conditioning lecture rooms and schoolrooms, and units for air conditioning rooms with cluster and server is processed in the second part. Project is derives from calculation thermal stress of air conditioned space. There is calculated price of air conditioner system and made comparison offers of several accessible suppliers. Elaboration drawing documentation of project is part of the diploma thesis.
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Reliability prediction of complex repairable systems : an engineering approachSun, Yong January 2006 (has links)
This research has developed several models and methodologies with the aim of improving the accuracy and applicability of reliability predictions for complex repairable systems. A repairable system is usually defined as one that will be repaired to recover its functions after each failure. Physical assets such as machines, buildings, vehicles are often repairable. Optimal maintenance strategies require the prediction of the reliability of complex repairable systems accurately. Numerous models and methods have been developed for predicting system reliability. After an extensive literature review, several limitations in the existing research and needs for future research have been identified. These include the follows: the need for an effective method to predict the reliability of an asset with multiple preventive maintenance intervals during its entire life span; the need for considering interactions among failures of components in a system; and the need for an effective method for predicting reliability with sparse or zero failure data. In this research, the Split System Approach (SSA), an Analytical Model for Interactive Failures (AMIF), the Extended SSA (ESSA) and the Proportional Covariate Model (PCM), were developed by the candidate to meet the needs identified previously, in an effective manner. These new methodologies/models are expected to rectify the identified limitations of current models and significantly improve the accuracy of the reliability prediction of existing models for repairable systems. The characteristics of the reliability of a system will alter after regular preventive maintenance. This alternation makes prediction of the reliability of complex repairable systems difficult, especially when the prediction covers a number of imperfect preventive maintenance actions over multiple intervals during the asset's lifetime. The SSA uses a new concept to address this issue effectively and splits a system into repaired and unrepaired parts virtually. SSA has been used to analyse system reliability at the component level and to address different states of a repairable system after single or multiple preventive maintenance activities over multiple intervals. The results obtained from this investigation demonstrate that SSA has an excellent ability to support the making of optimal asset preventive maintenance decisions over its whole life. It is noted that SSA, like most existing models, is based on the assumption that failures are independent of each other. This assumption is often unrealistic in industrial circumstances and may lead to unacceptable prediction errors. To ensure the accuracy of reliability prediction, interactive failures were considered. The concept of interactive failure presented in this thesis is a new variant of the definition of failure. The candidate has made several original contributions such as introducing and defining related concepts and terminologies, developing a model to analyse interactive failures quantitatively and revealing that interactive failure can be either stable or unstable. The research results effectively assist in avoiding unstable interactive relationship in machinery during its design phase. This research on interactive failures pioneers a new area of reliability prediction and enables the estimation of failure probabilities more precisely. ESSA was developed through an integration of SSA and AMIF. ESSA is the first effective method to address the reliability prediction of systems with interactive failures and with multiple preventive maintenance actions over multiple intervals. It enhances the capability of SSA and AMIF. PCM was developed to further enhance the capability of the above methodologies/models. It addresses the issue of reliability prediction using both failure data and condition data. The philosophy and procedure of PCM are different from existing models such as the Proportional Hazard Model (PHM). PCM has been used successfully to investigate the hazard of gearboxes and truck engines. The candidate demonstrated that PCM had several unique features: 1) it automatically tracks the changing characteristics of the hazard of a system using symptom indicators; 2) it estimates the hazard of a system using symptom indicators without historical failure data; 3) it reduces the influence of fluctuations in condition monitoring data on hazard estimation. These newly developed methodologies/models have been verified using simulations, industrial case studies and laboratory experiments. The research outcomes of this research are expected to enrich the body of knowledge in reliability prediction through effectively addressing some limitations of existing models and exploring the area of interactive failures.
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