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Effects of solar radiation on buildings and thermal comfortZingano, Bernard Wilson January 2003 (has links)
This work was undertaken to investigate the perceived problem of Thermal Discomfort in Malawi. One observable effect of thermal discomfort was the amount of foreign exchange that was spent to import air conditioning devices. The purpose of the work was to find out, and quantify the problem of thermal discomfort and outline its effects to the people and country. In order to investigate the problem of thermal discomfort in depth in a place where the necessary data hardly existed a lot of work had to be done. The work has been outlined in four stages of research, analysis and documentation and these are as follows 1 Literature Review The subject of Thermal Comfort appears to be location specific, but the general principles are universal. In that context it was necessary to read widely on both historical and contemporary current work. The problem of thermal comfort in general was being discussed as early as 1758 and still remains a big area of research and discussion today. A considerable number of literature that specifically relate to the problem of thermal comfort in the tropics has been reviewed. The problem of scales for thermal comfort measurement has been discussed in detail. It is still not possible to quote a scale that is satisfactory. However, the recent approach of Adaptive Thermal Comfort Model seems to be closer to the answer than the others 2 Analysing Existing Relevant Information And Data In Malawi In the course of this work it was found out that quite a large amount of useful data existed in Malawi. However, this data was not standardised. Most of this data had to be cleaned and updated. Some of the old formulae are quoted in their original formats in order not to confuse the referencing. The data that exists in Malawi has been recorded on three types of instruments; namely the Gunn Bellum Spherical Pyranometer, the Camp Bell Stoke Sunshine Recorder and the Eppley Pyranometer. Most of the data was recorded using the Camp Bell Stokes Sunshine Recorder. The data recorded on the Gunn Bellum Spherical Pyranometer had to be related to that from the Camp Bell Stokes Sunshine Recorder. The former gave data that was more accurate as was found out when a comparison was made with data recorded on an Eppley Pyranometer. A paper on this subject was accepted for publication in the Renewable Energy Journal of WREN. Wind speeds, air temperatures, and humidity have been analysed to investigate the severity of thermal discomfort relative to locations in Malawi. This has resulted in the identification of three climatic zones. A tool for testing Thermal Discomfort severity of a location by calculating number Degree Days (D. d) if the altitude (AL) has been developed; as D. d = -575.994 In AL + 4226.6 3 Field Measurements In order to investigate some of the issues that came out of this work, it was felt simpler to conduct field measurements. For example it would have been possible to build typical experimental houses, and extract performance data on Thermal Comfort from these buildings. However, this approach would have been very expensive. On the other hand it was felt that it was possible to find in the field that were representative of typical buildings and could be prepared and tested to extract performance data for use in the work. The latter approach was adopted and has proved to be more realistic than the former. 4 Field Surveys There were certain areas where the only way to find information was not to conduct experiments but to conduct field conduct surveys. This was done once to find the Preferred Bath Water Temperature (PBWT) and deduce the Neutral Temperature Range for Malawi. This yielded very useful results. The first published paper on this work was in this area (copy of this publication is attached). The second area of field survey was to survey traditional buildings in seven selected districts stretching from latitude 9°S to 17°S; covering a terrestrial distance of over 1000 km; over altitudes from 52 to over 1600 metres above mean sea level (m. a. m. s. l). This again yielded very useful environmental data that explained why traditional buildings have certain structural elements as functions of the environment and the need to achieve Thermal Comfort. A number of useful equations have been developed. From that sub routine of this research of PBWT survey an equation was developed that related the bath temperature (h) to the air temperature (tab) as; tb =0.3772 tab + 36.4401. Part of this work was also published separately in 2001. From this equation the Thermal Comfort Temperature Range for Malawi was deduced as 22-27°C. From the survey of the traditional buildings, a number of structural elements were that are functions of Thermal Comfort were identified as derivatives of the desire to have Thermal Comfort in the buildings. A regression equation that can give values of irradiation of the locality in MJm 1 Day' was developed. Lastly the results have been extracted as recommendations directed at policy makers, and both Architects and Engineers to use this data and the results in their design work. It is also further recommended that the national buildings regulations could be updated and revised to incorporate some of the findings. It is strongly believed that some of the findings will be incorporated to update the two main Laws that regulate Public Health in Malawi. These are the Public Health Act; Cap. 34.01, and the Health and Safety at Work Act, 1977; of the Malawi Laws. All data that has been cleaned up or measured specifically for this work has been organised and tabulated into ready-to-use tables and are included.
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Cold exposure and thermal comfort among patients in prehospital emergency care : innovation research in nursingAléx, Jonas January 2015 (has links)
Background Patients’ cold exposure is a neglected problem in prehospital emergency care. Cold stress increases pain and anxiety and contributes to fear and an overall sense of dissatisfaction. When left untreated, cold stress disturbs vital body functions until ultimately reaches hypothermia. Aim The overall aim was to investigate patients’ experiences of thermal comfort and reactions to cold exposure in prehospital emergency care and to evaluate the effects of an intervention using active warming from underneath. Method Study I: Persons (n=20) injured in a cold environment in the north of Sweden were interviewed. Active heat was given to 13 of them. Study II: In wintertime, 62 patients were observed during prehospital emergency care. The field study was based on observations, questions about thermal discomfort, vital signs, and temperature measurements. Study III: Healthy young persons (n=23) participated in two trials each. Data were collected inside and outside a cold chamber. In one trial, the participants were lying on a regular ambulance stretcher and in a second trial on a stretcher supplied with a heated mattress. Outcomes were the Cold Discomfort Scale (CDS), back, finger, and core body temperature, four statements from the State-TraitAnxiety-Inventory (STAI), vital signs, and short notes about their experiences of the two stretchers. Study IV: A quantitative intervention study was conducted in prehospital emergency care in the north of Sweden. The patients (n=30) in the intervention group were transported in an ambulance supplemented with a heated mattress on the stretcher, whereas only a regular stretcher was used in the ambulance for the patients (n=30) in the control group. Outcomes were the CDS, finger, core body, and air temperature, and questions about cold experiences. Results Study I: Patients suffered more because of the cold than from the pain of their injuries. The patients were in a desperate need of heat. Study II: Patients are exposed to cold stress due to cold environments. There was a significant decrease from the first measurement in finger temperature of patients who were indoors when the ambulance arrived, compared to the measurement taken in the ambulance. In the patient compartment of the ambulance, 85% of the patients had a finger temperature below the comfort zone and almost half of them experienced the patient compartment in the ambulance to be cold. The regular mattress surface temperature at the ambulance ranged from -22.3 to 8.4 ºC. Study III: A statistical increase of the participants’ back temperature was found between those lying on the heated mattress compared to those lying on the regular mattress. The heated mattress was experienced as warm, comfortable, providing security, and easy to relax on. Study IV: Thermal comfort increased for the patients in the intervention group and decreased in the control group. A significant higher proportion of the participants rated the stretcher as cold to lie on in the control group compared to the intervention group. Conclusion The ambulance milieu is too cold to provide thermal comfort. Heat supply from underneath increased comfort and might prevent cold stress and hypothermia
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Arquiteturas de distribuição de ar em cabines de aeronaves: análise experimental de desconforto térmico local. / Air distribution architectures in aircraft cabins: experimental analysis of local thermal discomfort.Silva, Evandro Souza da 18 October 2013 (has links)
O sistema de ventilação por mistura (MV), utilizado atualmente em cabines de aeronaves na distribuição do ar tratado, não tem propiciado condições adequadas de conforto térmico e pode, devido às suas características de mistura, propagar rapidamente doenças infecciosas na cabine. Sistemas de ventilação utilizados em ambientes de edificações, como o sistema de distribuição de ar por deslocamento (DV) e o sistema de distribuição de ar pelo piso (UFAD) e variantes destes sistemas, estão começando a ser propostos. Função disto, o presente trabalho comparou três arquiteturas de distribuição de ar: o sistema tradicional (MV), o sistema de insuflamento de ar pelo piso (UFAD) e uma variação do sistema UFAD, incluindo insuflamento lateral abaixo dos bagageiros, denominado de UFAD modificado. Os ensaios foram realizados em cabine de mock up de aeronave com 12 lugares, ocupados por manequins aquecidos simulando os passageiros, considerando duas temperaturas para o ar insuflado na cabine: 18°C e 22°C. Os resultados mostram influência significativa da temperatura de insuflamento do ar nas condições de desconforto térmico local, juntamente com resultados promissores para o sistema UFAD, com percentuais de desconforto devido às correntes de ar menores que 20%, com exceção da região de insuflamento do ar no corredor. / Mixing ventilation system (MV), currently used in aircraft cabins for treated air distribution, has not provided adequate conditions for thermal comfort and may, due to its mixing characteristics, spread quickly infectious diseases in the cabin. Ventilation systems used in buildings environments, such as displacement ventilation system (DV) and underfloor air distribution system (UFAD) and variants of these systems are beginning to be proposed. Due to that, the present study compared three air distribution architectures: the traditional system (MV), underfloor air distribution system (UFAD) and a variation of the UFAD system, including side air supply under bins, called UFAD modified. Tests were performed in aircraft cabin mock up with 12 seats, occupied by heated manikins simulating passengers, considering two air supply temperatures into the cabin: 18°C and 22°C. Results show significant influence of air supply temperature in conditions of local thermal discomfort, together with promising results for UFAD system, with percentages of discomfort due to draught less than 20%, except in the air insufflation area in aisle.
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Arquiteturas de distribuição de ar em cabines de aeronaves: análise experimental de desconforto térmico local. / Air distribution architectures in aircraft cabins: experimental analysis of local thermal discomfort.Evandro Souza da Silva 18 October 2013 (has links)
O sistema de ventilação por mistura (MV), utilizado atualmente em cabines de aeronaves na distribuição do ar tratado, não tem propiciado condições adequadas de conforto térmico e pode, devido às suas características de mistura, propagar rapidamente doenças infecciosas na cabine. Sistemas de ventilação utilizados em ambientes de edificações, como o sistema de distribuição de ar por deslocamento (DV) e o sistema de distribuição de ar pelo piso (UFAD) e variantes destes sistemas, estão começando a ser propostos. Função disto, o presente trabalho comparou três arquiteturas de distribuição de ar: o sistema tradicional (MV), o sistema de insuflamento de ar pelo piso (UFAD) e uma variação do sistema UFAD, incluindo insuflamento lateral abaixo dos bagageiros, denominado de UFAD modificado. Os ensaios foram realizados em cabine de mock up de aeronave com 12 lugares, ocupados por manequins aquecidos simulando os passageiros, considerando duas temperaturas para o ar insuflado na cabine: 18°C e 22°C. Os resultados mostram influência significativa da temperatura de insuflamento do ar nas condições de desconforto térmico local, juntamente com resultados promissores para o sistema UFAD, com percentuais de desconforto devido às correntes de ar menores que 20%, com exceção da região de insuflamento do ar no corredor. / Mixing ventilation system (MV), currently used in aircraft cabins for treated air distribution, has not provided adequate conditions for thermal comfort and may, due to its mixing characteristics, spread quickly infectious diseases in the cabin. Ventilation systems used in buildings environments, such as displacement ventilation system (DV) and underfloor air distribution system (UFAD) and variants of these systems are beginning to be proposed. Due to that, the present study compared three air distribution architectures: the traditional system (MV), underfloor air distribution system (UFAD) and a variation of the UFAD system, including side air supply under bins, called UFAD modified. Tests were performed in aircraft cabin mock up with 12 seats, occupied by heated manikins simulating passengers, considering two air supply temperatures into the cabin: 18°C and 22°C. Results show significant influence of air supply temperature in conditions of local thermal discomfort, together with promising results for UFAD system, with percentages of discomfort due to draught less than 20%, except in the air insufflation area in aisle.
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Estudo do campo térmico: o caso do Campus IV - UFPBMelo, Beatriz Cristina Barbalho de 30 September 2015 (has links)
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Previous issue date: 2015-09-30 / The microclimate consequences of a particular place to demonstrate that he as
urban growth and exploitation of natural resources are increasing unfortunately. The
weather is the most important component in maintaining the ecological balance. And
his study becomes complex due to the various facets that involve him, turning
indispensable interdisciplinary study, it could help in the reduction and / or more
efficient solution of the urban problems. Studies of this order become relevant to
planning and environmental management, which arouses interest for research on the
thermal field of urban areas. The problem of this research is related to concern about
anthropogenic implications on the local microclimate. It is known that human actions
on the microclimate and the lack of proper planning of a particular place, can
contribute to the thermal discomfort of users and demand higher energy costs. The
present search, has as main objective to analyze the field thermal the Campus IVUFPB,
located in the city of Rio Tinto-PB. In this case, seeks if relate the
anthropogenic actions with the main thermal problems, detected on site. To obtain
microclimate data, were installed in similar (which takes into account the type of soil
cover, in this case, coating in cementitious composition) points, measuring
equipment, in six points within the campus IV- UFPB, in dry season (from March 04
to April 7, 2015) and during the rainy season (from 09 June to 13 July 2015),
totalizing 35 days in each measurement period. From the analysis and management
of the data obtained, the presence of heat islands was detected within the study area
as well as the rise in temperature in places with low circulation of winds and
decreased moisture and the low individuals presence of arboreal. The results allowed
the elaboration of suggestions with proposed thermal environmental, as; the ceramic
roof replacement, in the hottest areas for green cover; replacing paving stones and
interlocked block, per tread grass, that provide the minimization of thermal effects
identified in the Campus IV-UFPB. With this, this research, can to corroborate to
reveal the adverse effects of the anthropogenic actions that provoke microclimatic
modifications in the thermal field of Campus IV-UFPB, making a relation with its
urban components. / As consequências microclimáticas de um determinado local demonstram o quão
desastrosamente o crescimento urbano e a exploração dos recursos naturais vêm
aumentando. O clima é o componente mais importante na manutenção do equilíbrio
ecológico. E seu estudo se torna complexo devido às diversas facetas que o
envolvem, tornando imprescindível o estudo interdisciplinar que pode auxiliar, na
diminuição e/ou solução mais eficiente das problemáticas do meio urbano. Estudos
dessa ordem se tornam relevantes para o ordenamento e a gestão ambiental, o que
desperta interesse para pesquisas sobre o campo térmico de áreas urbanas. A
problemática desta pesquisa está relacionada com a preocupação sobre as
implicações antrópicas sobre o microclima local. Sabe-se que as ações antrópicas
sobre o microclima e a falta de planejamento adequado de um determinado local,
podem contribuir para o desconforto térmico dos usuários e demandar maiores
custos energéticos. A presente pesquisa tem como objetivo geral analisar o campo
térmico do Campus IV-UFPB, localizado na cidade de Rio Tinto-PB. Nesse caso
procura-se relacionar as ações antropogênicas com as principais problemáticas
térmicas, detectadas no local. Para a obtenção de dados microclimáticos, foram
instalados, em pontos semelhantes (que levam em consideração o tipo de
recobrimento do solo, neste caso, revestimento de composição cimentícia),
equipamentos de medição, em seis pontos dentro do campus IV-UFPB, no período
seco (de 04 de Março a 07 de Abril de 2015) e no período chuvoso (de 09 de Junho
a 13 de Julho de 2015), somando-se 35 dias em cada período de medição. A partir
da análise e ordenamento dos dados coletados, ficou constatada a presença de
ilhas de calor dentro da área de estudo, bem como o aumento de temperatura em
locais com pouca circulação dos ventos e a diminuição da umidade em locais com
pouca presença de indivíduos arbóreos. A análise dos resultados permitiu elaborar
sugestões com propostas termo ambientais do tipo, substituição de telhado
cerâmico, nas áreas mais quentes, por telhado verde extensivo; a substituição de
paralelepípedos e blocos intertravados, por piso grama que proporcionem a
minimização dos efeitos térmicos identificados, no Campus IV-UFPB. Com isso, esta
pesquisa, pode vir a corroborar no desvendar dos efeitos adversos das ações
antropogênicas, que provocam alterações microclimáticas no campo térmico do
Campus IV-UFPB, fazendo uma relação com seus componentes urbanos.
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Heat waves in South Africa: Observed variabilty, structure and trendsMbokodo, Innocent Lifa 18 May 2017 (has links)
MENVSC (Climatology) / Department of Geography and Geo-Information Sciences / Heat waves are warm extreme temperature events that have environmental and socio-economic impacts in many regions across the world. Negative impacts of warm extreme temperatures over South Africa necessitate the need to study the nature of heat waves. Observations and satellite datasets are analysed in the investigation of the nature and trends of heat waves over South Africa in the present (1983-2012) and future (2010-2039, 2040-2069, 2070-2099) climates. Case study and composite analysis of National Centers for Environmental Prediction datasets were done using the Grids Analysis and Display Systems to get an in-depth understanding of the structure of heat waves in South Africa. Future climate model output obtained from the Conformal Cubic Atmospheric Model was used for future heat wave trends in South Africa. The simulations were made using the Representative Concentration Pathways 4.5 and 8.5. Heat waves are unusual events in the present climate (1983-2012) over much of the country, with 20 of the selected 24 stations experiencing an average of less than one heat wave per season. Heat waves are also more frequent and last longer during warm phase of El Niño-Southern Oscillation (ENSO) than in cool phase of ENSO with the north-east being the most prone region. Composite analysis of 500 hPa omega indicates subsidence over the interior of South Africa in both phases of ENSO. Heat waves in South Africa are localized and associated with a middle level high pressure system that persists over the interior inducing anticyclonic flow and subsidence. The anticyclonic circulation over a region experiencing heat wave weakens with decreasing height over land areas which may be due to frictional forces at the surface and the high is placed further south-east at the surface. Advection of dry continental northerly winds also contributes to high maximum temperatures during heat waves in the interior. Maximum temperatures are expected to increase drastically from the present-day climate to the 2070 – 2099 period, with an average increment of about 8°C during DJF in much of the central interior. As a result, heat wave occurrences are expected to be higher in the future warmer climates when climate change signal is higher. Most increases are expected for heat waves lasting for a week than those lasting for over 2 weeks. CCAM outputs also indicated that heat waves in South Africa are expected to last longer and become more intense during the future warmer climates. Longer lasting and more intense heat waves are expected over the Karoo than in other parts of the country.
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Investigating The Relationship Between Mean Radiant Temperature (MRT) And Predicted Mean Vote (PMV) : A case study in a University buildingGodbole, Swapnil January 2018 (has links)
Thermal comfort in an indoor environment is largely dependent on the four environmental and two personal parameters which is most commonly measured by the Predicted Mean Vote (PMV) model developed by Fanger. It has been studied that variations in these parameters beyond a range could lead to discomfort complaints. However, little research has been done on the effect of mean radiant temperature variations and its influence on predicted mean vote and thermal comfort specially in an actual building environment. This study aims to investigate the relationship between mean radiant temperature and predicted mean vote in indoor environment. Using the methods of on-site measurement of indoor environmental parameters and subjective votes on thermal sensation in an educational building; it was found that rise in mean radiant temperature lead to rise in PMV value and discomfort vote amongst occupants seated near glazed façade. A very strong positive correlation was found between mean radiant temperature and PMV near the window side of the room under warm and sunny weather conditions. Analysis of indoor environmental data from the several measurement sessions concluded that rise in mean radiant temperature and PMV was not noticed until there was a direct solar transmission through the window. It is advisable to use solar shading on windows, but special consideration should be given to the trade-offs between energy consumption (heating or cooling) and lighting energy consumption. No conclusions could be made in terms of ankle draft discomfort due to experimental limitations and more research would be required to investigate this phenomenon. / Termisk komfort inomhusmiljö är till stor del beroende av de fyra miljö och två personlig parametrar som oftast mäts av Predicted Mean Vote (PMV) modell som utvecklats av Fanger. Det har studerats att variationer i dessa parametrar utanför en limit kan leda till missnöjeklagomål. Däremot har lite forskning gjorts på effekten av mean radiant tempratur och dess inverkan på predicted mean vote och termisk komfort speciellt i en verklig byggnadsmiljö. Syftet med denna studie är att undersöka sambandet mellan mean radiant tempratur och predicted mean vote i inomhusmiljö. Användning mätmetoderna av inomhusmiljöparametrar och subjektiva röster av termisk komfort uppfattning i en byggnad för utbildning; det konstaterades att stiga i medel leda mean radiant tempratur att stiga i predicted mean vote värde och missnöje rösta bland byggnad brukarna sitter nära glasfasaden. En väldigt positiv korrelation mellan men radiant tempratur och predicted mean vote nära en fönstersida under varma och soliga väder var noterat. Genom att analysera data av inomhusmiljön från de multipla mätningssessionerna konkluderat att ökningen i mean radiant tempratur och predicted mean vote inte märktes tills det fanns en direkt soltransmission genom fönstret. Det är rekommenderar att använda solskydd på fönster, men med tanke på kompromisser mellan energiförbrukning (värme eller kyla) och ljussättning konsumtion. Inga slutsatser kan göras om luftdrag på fotled grund av experimentella begränsningar och mer forskning skulle krävas för att undersöka detta fenomen.
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Deep Reinforcement Learning for Building Control : A comparative study for applying Deep Reinforcement Learning to Building Energy Management / Djup förstärkningsinlärning för byggnadskontroll : En jämförande studie för att tillämpa djup förstärkningsinlärning på byggnadsenergihushållningZheng, Wanfu January 2022 (has links)
Energy and environment have become hot topics in the world. The building sector accounts for a high proportion of energy consumption, with over one-third of energy use globally. A variety of optimization methods have been proposed for building energy management, which are mainly divided into two types: model-based and model-free. Model Predictive Control is a model-based method but is not widely adopted by the building industry as it requires too much expertise and time to develop a model. Model-free Deep Reinforcement Learning(DRL) has successful applications in game-playing and robotics control. Therefore, we explored the effectiveness of the DRL algorithms applied to building control and investigated which DRL algorithm performs best. Three DRL algorithms were implemented, namely, Deep Deterministic Policy Gradient(DDPG), Double Deep Q learning(DDQN) and Soft Actor Critic(SAC). We used the building optimization testing (BOPTEST) framework, a standardized virtual testbed, to test the DRL algorithms. The performance is evaluated by two Key Performance Indicators(KPIs): thermal discomfort and operational cost. The results show that the DDPG agent performs best, and outperforms the baseline with the saving of thermal discomfort by 91.5% and 18.3%, and the saving of the operational cost by 11.0% and 14.6% during the peak and typical heating periods, respectively. DDQN and SAC agents do not show a clear advantage of performance over the baseline. This research highlights the excellent control performance of the DDPG agent, suggesting that the application of DRL in building control can achieve a better performance than the conventional control method. / Energi och miljö blir heta ämnen i världen. Byggsektorn står för en hög andel av energiförbrukningen, med över en tredjedel av energianvändningen globalt. En mängd olika optimeringsmetoder har föreslagits för Building Energy Management, vilka huvudsakligen är uppdelade i två typer: modellbaserade och modellfria. Model Predictive Control är en modellbaserad metod men är inte allmänt antagen av byggbranschen eftersom det kräver för mycket expertis och tid för att utveckla en modell. Modellfri Deep Reinforcement Learning (DRL) har framgångsrika tillämpningar inom spel och robotstyrning. Därför undersökte vi effektiviteten av DRL-algoritmerna som tillämpas på byggnadskontroll och undersökte vilken DRL-algoritm som presterar bäst. Tre DRL-algoritmer implementerades, nämligen Deep Deterministic Policy Gradient (DDPG), Double Deep Q Learning (DDQN) och Soft Actor Critic (SAC). Vi använde ramverket Building Optimization Testing (BOPTEST), en standardiserad virtuell testbädd, för att testa DRL-algoritmerna. Prestandan utvärderas av två Key Performance Indicators (KPIs): termiskt obehag och driftskostnad. Resultaten visar att DDPG-medlet presterar bäst och överträffar baslinjen med besparingen av termiskt obehag med 91.5% och 18.3%, och besparingen av driftskostnaden med 11.0% och 14.6% under topp och typisk uppvärmning perioder, respektive. DDQN- och SAC-agenter visar inte en klar fördel i prestanda jämfört med baslinjen. Denna forskning belyser DDPG-medlets utmärkta prestanda, vilket tyder på att tillämpningen av DRL i byggnadskontroll kan uppnå bättre prestanda än den konventionella metoden.
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