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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Arborização na cidade de Campinas/SP- percepção e conforto / Street trees in the city of Campinas/SP - comfort and perception

Léa Yamaguchi Dobbert 13 February 2015 (has links)
A influência benéfica de áreas verdes no conforto humano em áreas urbanas tem sido reconhecida por estudos de diferentes campos do conhecimento. Áreas verdes e arborização bem planejada constituem importantes recursos para melhorar a qualidade do ambiente ao promover bem-estar físico e mental aos seus usuários. Avaliar o grau de interferência proporcionado pela arborização no conforto térmico e bem-estar da população foi o objetivo principal do presente estudo. O índice de floresta urbana (IFU) avaliou a interferência da quantidade de cobertura arbórea em quatro áreas da cidade de Campinas/SP/Brasil em relação às condições de conforto térmico. Para tanto, foram utilizados índices de avaliação de conforto térmico (PMV Predicted Mean Vote e PET- Physiologically Equivalent Temperature) obtidos por meio do modelo Ray Man Pro.Questionários aplicados aos usuários das áreas de estudo possibilitaram verificar se os resultados obtidos por meio dos índices PMV e PET correspondiam à real sensação de conforto térmico relatada pelos entrevistados.Simulações com o uso do programa ENVI-met v. 3.1 foram realizadas a fim de observar as interferências microclimáticas causadas pela inserção de vegetação no meio urbano. A percepção do usuário das áreas de estudo em relação à arborização urbana também foi identificada por meio de questionários. Essa pesquisa permitirá no futuro, a partir dos resultados levantados, construir um instrumento para ser incorporado no plano diretor de arborização urbana, possibilitando urbanistas e profissionais, que atuam de forma direta ou indireta no planejamento das cidades, inspecionar e analisar o conforto térmico e a qualidade de vida no meio urbano, tendo em vista a valorização e adequação da arborização viária em seus projetos. / The benefits of green urban area on human comfort have been recognized by studies performed in different knowledge fields. Green areas and urban forest planning are important tool to improve the quality of the urban environment by promoting physical and mental wellbeing to its users. The main goal of the present study is to assess the interference promoted by green areas in the welfare and thermal comfort of the urban population. The Urban Forest Index (IFU) evaluated the interference of the amount of trees in four areas of the city of Campinas, in the state of São Paulo, Brazil in relation to the conditions for thermal comfort. For this purpose, comfort indices have been used for evaluating thermal comfort (PMV-Predicted Mean Vote and PET-Physiologically Equivalent Temperature), obtained by the RayMan model. Questionnaires applied to the users on these study areas aimed to verify if the results of PET and PMV indices corresponded to the thermal sensation by respondents. Simulations using the ENVI-met program v 3.1 were conducted to observe the interference on microclimate due to the presence of vegetation in the urban environment. Questionnaires were also used to assess the perception of users on urban street trees. In the future, results obtained in this study will allow the building of an instrument, which could be included in the urban forest master plan. As a result, urban planners and other professionals who work directly or indirectly in the planning of cities will be able to inspect and evaluate the thermal comfort and the welfare of their citizens, considering the recovery and suitability of urban street trees in their projects.
12

Urban heat Island mitigation strategies in an arid climate. In outdoor thermal comfort reacheable / Réduction des ilots de chaleur urbains sous climat aride. Le confort extérieur est-il possible

Ridha, Suaad 28 April 2017 (has links)
De nombreuses études au cours des dernières décennies ont porté sur l'effet l’îlot de chaleur urbain (ICU). Les efforts initiaux visant à comprendre les facteurs qui influent sur l’ICU ont contribué à la mise en place de solutions et de stratégies d'atténuation adaptées. Les stratégies d'atténuation comprennent généralement l'augmentation de l'albédo urbain (réflectivité au rayonnement solaire) et l'évapotranspiration. Les augmentations d'albedo sont obtenues grâce à des technologies de toiture et de pavage ayant un albédo élevé. Une augmentation de l'évapotranspiration est obtenue par une combinaison de la diminution de la fraction de surfaces imperméables et la plantation de végétation dans les zones urbaines. Le confort thermique extérieur est défini à partir d’indices prenant en compte différents paramètres physiques et traduit la perception et la satisfaction des piétons. Ce confort est très difficile à obtenir en climat chaud et aride. Par conséquent, le travail présenté dans ce document met l'accent sur les méthodes appropriées pour réduire l’ICU et ainsi améliorer le confort thermique en plein air des piétons. Jusqu’à présent, peu de recherches ont été menées sur le confort thermique extérieur dans un climat chaud et aride. Les études sur l'atténuation de l'ICU et le confort thermique extérieur sont pratiquement inexistantes pour la ville de Bagdad. Bagdad a un tissu urbain complexe avec des constructions modernes, des maisons traditionnelles et des éléments caractéristiques du patrimoine local. Le climat en été est chaud, et les mois d'été sont considérés comme la plus longue saison avec près de 7 mois de l'année. Dans un premier temps, cette étude se concentre sur l'étude des stratégies d'atténuation à envisager afin d’évaluer comment le confort des piétons est affecté par les choix de conception des constructions, en comparant un quartier traditionnel à un quartier moderne. L’étude envisage ensuite la façon dont la végétation et les ombrages contribuent à réduire l'effet de l'ICU et à améliorer le confort thermique extérieur. Quatre scénarios différents sont élaborés pour évaluer le rôle d’éléments végétaux tels que les arbres, l'herbe et les différents modèles d'ombrage. L'évaluation a été effectuée le jour le plus chaud de l'été, la température radiante moyenne, l'humidité spécifique, la température de l'air et les distributions de la vitesse du vent ont été analysées à l'aide du logiciel ENVI-met. Le confort thermique est ensuite évalué à l'aide des indices thermiques de la température équivalente physiologique PET et du PMV étendu aux ambiances extérieures. En outre, une proposition de solution est abordée afin d’étudier son impact sur le confort thermique pour la journée la plus chaude (situation extrême) et une journée typique d’été. Les résultats ont révélé une amélioration du confort thermique dans la journée typique d’été. L'étude montre comment les facteurs urbains tels que le rapport d'aspect, la couverture végétale, les ombres et la géométrie du quartier sont des éléments cruciaux que les urbanistes et les municipalités doivent prendre en compte, en particulier pour les nouveaux aménagements urbains dans un climat chaud et aride. Une proposition d’aménagement global pour atténuer les ICU dans le cas d’un nouveau quartier sous climat aride, est détaillée en fin de mémoire. / Numerous studies over the past several decades focused on the effect of the Urban Heat Island. Initial efforts on understanding the factors affecting UHI contributed to proceed the appropriate solutions and mitigation strategies. Mitigation strategies comprise increase both urban albedo (reflectivity to solar radiation), and evapotranspiration. Albedo increases are obtained through high albedo roofing and paving technologies. An increase in evapotranspiration is achieved through a combination of decreasing the fraction of impervious surfaces and planting vegetation in urban areas. The outdoor thermal comfort is influenced by the perception and satisfaction of the pedestrians, especially in hot and arid climates. Consequently, this work focuses on the appropriate methods for reducing the Urban Heat Island and thus to enhance the pedestrians outdoor thermal comfort. However, there is limited research conducted on the outdoor thermal comfort in hot and arid climate. The studies on the mitigation the Urban Heat Island and the outdoor thermal comfort are almost non-existent for Baghdad city. Baghdad has a complex urban fabric with modern design constructions buildings, traditional and heritage houses. The climate in summer is hot, and summer months are considered the longest season with nearly 7 months of the year. This study focuses on investigating possible mitigation strategies to ensure how pedestrian comfort is affected by the constructions design choices comparing a traditional district to a modern one, and on how vegetation and shading patterns contribute to reducing the effect of UHI and improving the outdoor thermal comfort. Four different scenarios are designed to assess the role of vegetation elements such as trees, grass, and different shading patterns. The evaluation was performed on the hottest day in summer, the mean radiant temperature, specific humidity, air temperature, and wind speed distributions have been analyzed using ENVI-met software. Thermal comfort is assessed using the thermal indices the Physiological Equivalent Temperature PET and the Predicted Mean Vote PMV. Also, a proposal model is designed to evaluate the thermal comfort on the hottest day and the typical day in summer. The results revealed an improvement on thermal comfort in the typical day in summer. The study shows how the urban factors such as the aspect ratio, vegetation cover, shadings, and geometry of the canyon are crucial elements that urban planners and municipalities have to take into account, especially for new urban developments in hot, arid climate.
13

Termisk komfort med golvvärme eller luftvärme / Thermal comfort with floor heating or air heating

Boåsen, Filip, Khaled, Stiven January 2018 (has links)
Då varje människa tillbringar större del av dagen inomhus så är det viktigt att ha en bra termisk komfort, efter som den termiska komforten påverkar upplevelsen på jobbet i hemmet eller i skolan. Människor kan påverkas negativt när den termiska komforten inte uppfyller kraven.   Syftet med undersökningen är att undersöka hur lågtemperaturssystemens förmåga är med avseende på termisk komfort och om de uppfyller kraven. Undersökningen använder beräknings data från tidigare utfört arbete då beräkningarna valideras av jämförelse mot andra undersökningar.   I detta arbete undersöker vi skillnader mellan golvvärme och luftvärme, där vi ser hur de olika systemen jämförs mot varandra under kontrollerade förhållanden med avseende på termisk komfort. De olika systemen som undersöks är luftvärme som är placerad under tak, luftvärme placerad under ett fönster, golvvärme som är jämnfördelad över golvet och golvvärme jämnfördelad med extra slingor under fönster. I undersökningen utförs en litteraturstudie som kommer att ligga till grund för vad ämnet för lågtemperatur innefattar samt hur de olika systemen fungerar och hur dessa kan användas som lågtemperaturssystem. Då i denna undersökningen så beaktas operativa temperaturen PMV, PPD och dragindex för att få en bra uppfattning hur den termiska komforten upplevs med avseende på golvvärme och luftvärme. Undersökningen har gett goda resultat då skillnaden i termisk komfort mellan de olika systemen har varit minimala och uppfyllt alla krav enligt BBR. Resultaten har jämförts mot tidigare gjorda undersökningar av lågtemperaturteknik och resultaten sammanfaller bra med små avvikelser. För att välja ett av de fyra systemen som har visats bättre resultat med hänsyn på termisk komfort så har golvvärme med extra slingor under fönster bevisats vara det bättre alternativet, då PMV och PPD samt drag ligger under rekommendationen för termisk komfort. / When most people spend a larger part of the day indoors, it is important to have a good thermal comfort, as the thermal comfort affects the experience that you perceive when you are at work, at home or at school. This may then affect the health if the thermal comfort does not meet the requirements. The purpose of the survey is to investigate low temperature system performance in terms of thermal comfort and if it meets the requirements. The survey uses calculation data from previously performed surveys, as the calculations are validated by comparison with other surveys. In this survey we explore the differences between floor heating and air heating, where we look at how the different systems are compared to each other under controlled conditions regarding thermal comfort. The different systems under investigation are air heating placed on the wall, air heating placed under a window, floor heating evenly distributed over the floor and floor heating that has extra loops under windows. The study will carry out a literature study that will be based on the topic of low temperature and how the different systems work and how they can be used at low temperatures. In this survey, the operating temperature PMV, PPD and DR-index are considered to get a good idea of how thermal comfort is experienced regarding floor heating or air heating. The survey has given good results, since the difference in thermal comfort between the different systems has been minimal and fulfilled all BBR requirements. The results have been compared to previous studies of low temperature technology, as the results coincide well with minor deviations. To choose one of the four systems that have been shown superior in terms of thermal comfort, floor heating with extra loops under windows has been proven to be the better option, as PMV and PPD as well as values are below the recommendation for thermal comfort.
14

Indoor climate : A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting

Abreu Saraiva Freitas, Iuri January 2018 (has links)
This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.
15

Áreas verdes hospitalares - percepção e conforto / Hospital Green areas Perception and Comfort

Dobbert, Léa Yamaguchi 18 January 2011 (has links)
Nas primeiras décadas do século XX, profissionais da área da saúde investiram em ambientes funcionais de trabalho, dando ênfase à implantação de equipamentos de alta tecnologia, sem se preocuparem com o grau de conforto proporcionado pelo ambiente físico. Trabalhos científicos nesta área classificaram esses espaços como estressantes e inadequados em razão de não observarem as carências emocionais e psicológicas dos usuários. O presente estudo avaliou a melhoria do conforto humano na Irmandade Santa Casa de Valinhos/SP-Brasil, proporcionado pela requalificação de áreas verdes existentes entre as alas de internação. Para avaliar o grau de conforto térmico proporcionado por essas áreas verdes requalificadas, utilizaram-se dois modelos preditivos de conforto: o Predicted Mean Vote - PMV (FANGER, 1970) e o Predicted Percentage of Disatisfied - PPD baseado na ISO 7730 (1994) para ambientes internos. A fim de se compararem os resultados obtidos com base nos modelos preditivos à percepção subjetiva do conforto térmico dos entrevistados, foram aplicados questionários contendo questões abertas e fechadas que possibilitaram uma análise dos benefícios terapêuticos proporcionados pelas áreas verdes requalificadas. Outro instrumento utilizado, o Inventário de Sintomas de Stress de LIPP, avaliou e comparou o nível de stress entre dois grupos de funcionários (com contato e sem contato com áreas verdes). Os resultados deste estudo demonstram que os espaços verdes requalificados, apesar de ainda não interferirem no grau de conforto térmico dos ambientes a eles adjacentes, cumprem um papel terapêutico na medida em que promovem maior bem-estar a todos que deles se usufruem. / In the first decades of the twentieth century, health professionals have invested into functional work environments, emphasizing the insertion of high-tech equipment and not concerned about the comfort provided by the physical environment. Scientific work in this area ranked these spaces as stressful and inappropriate in order not to observe the emotional and psychological necessities the users have. This study has evaluated the improvement of human comfort in Santa Casa de Valinhos / SP-Brazil, provided by the recovery of green areas between the internment wards at the hospital. To evaluate the thermal comfort degree provided by these recovered green areas, we have used two predictive comfort models: Predicted Mean Vote - PMV (FANGER, 1970) and Predicted Percentage of Disatisfied - PPD based on ISO 7730 (1994) for indoor environments. In order to compare the results based on predictive models to the subjective perception of the thermal comfort, questionnaires have been applied with open and closed questions which have allowed an analysis of therapeutic benefits provided by the recovered green areas. The other instrument used was Lipp Stress Symptom Inventory, which evaluated and compared the level of stress among two staff groups (with or without contact to the green areas). The results of this study have demonstrated that the recovered green spaces, while not influencing the thermal comfort degree of adjacent environments, which has a therapeutic role while promoting a greater well-being to all who enjoy them.
16

Conforto térmico na indústria do papel

Martins, António Manuel Quental January 2011 (has links)
Tese de mestrado. Engenharia de Segurança e Higiene Ocupacionais. Faculdade de Engenharia. Universidade do Porto. 2011
17

Construction and Evaluation of a Controlled Active Mass (CAM) : A new cooling system design for increased thermal comfort using low exergy sources

Ghahremanian, Shahriar, Janbakhsh, Setareh January 2007 (has links)
<p>Nowadays, office buildings often have large temperature variations during the day and building envelope acts as an energy storing mass and damp these effects and so Offices need more cooling because of internal heat sources. But we know that cooling is more expensive than heating and it uses the very good quality of energy sources (exergy). Controlled Active Mass (CAM) is new approach to absorb radiant heating and acts as a passive cooling device. It has direct cooling effect and reduces the peak load. CAM is a new cooling system design with applying the low energy sources and operates at water temperature close to room temperature and increase the efficiency of heat pumps and other systems.</p><p>In this project, we calculated the transient heat transfer analysis for CAM in a very well insulated test room with façade wall, Internal heat generators (such as Manikin, Computer simulator & lighting) and ventilation.</p><p>Then Polished (shiny) CAM constructed from Aluminum sheets with 0.003 m thickness. It is cube shape with 0.6 m length. This size of CAM is according to 2.5 times larger than human body volume and initial water temperature assumed near half of human body temperature. Then in order to more radiation damping (absorption) by CAM, it painted black (also based on color analysis in heat transfer calculation).</p><p>Some velocity and temperature measurement have been carried out on both polished CAM and black CAM, after visualization by smoke and Infrared Camera. And more cases tested to see the effect of façade wall, IHG’s and ventilation inlet temperature. Thermal comfort measurement also have been done for finding PMV, PPD and temperature equivalent for a seated person which is doing an office job with normal closing.</p><p>At the end results discussed which includes the effect of CAM in room, differences between polished CAM and black CAM and effect of main heat sources on both CAM types (Polished / Black).</p>
18

Construction and Evaluation of a Controlled Active Mass (CAM) : A new cooling system design for increased thermal comfort using low exergy sources

Ghahremanian, Shahriar, Janbakhsh, Setareh January 2007 (has links)
Nowadays, office buildings often have large temperature variations during the day and building envelope acts as an energy storing mass and damp these effects and so Offices need more cooling because of internal heat sources. But we know that cooling is more expensive than heating and it uses the very good quality of energy sources (exergy). Controlled Active Mass (CAM) is new approach to absorb radiant heating and acts as a passive cooling device. It has direct cooling effect and reduces the peak load. CAM is a new cooling system design with applying the low energy sources and operates at water temperature close to room temperature and increase the efficiency of heat pumps and other systems. In this project, we calculated the transient heat transfer analysis for CAM in a very well insulated test room with façade wall, Internal heat generators (such as Manikin, Computer simulator &amp; lighting) and ventilation. Then Polished (shiny) CAM constructed from Aluminum sheets with 0.003 m thickness. It is cube shape with 0.6 m length. This size of CAM is according to 2.5 times larger than human body volume and initial water temperature assumed near half of human body temperature. Then in order to more radiation damping (absorption) by CAM, it painted black (also based on color analysis in heat transfer calculation). Some velocity and temperature measurement have been carried out on both polished CAM and black CAM, after visualization by smoke and Infrared Camera. And more cases tested to see the effect of façade wall, IHG’s and ventilation inlet temperature. Thermal comfort measurement also have been done for finding PMV, PPD and temperature equivalent for a seated person which is doing an office job with normal closing. At the end results discussed which includes the effect of CAM in room, differences between polished CAM and black CAM and effect of main heat sources on both CAM types (Polished / Black).
19

Áreas verdes hospitalares - percepção e conforto / Hospital Green areas Perception and Comfort

Léa Yamaguchi Dobbert 18 January 2011 (has links)
Nas primeiras décadas do século XX, profissionais da área da saúde investiram em ambientes funcionais de trabalho, dando ênfase à implantação de equipamentos de alta tecnologia, sem se preocuparem com o grau de conforto proporcionado pelo ambiente físico. Trabalhos científicos nesta área classificaram esses espaços como estressantes e inadequados em razão de não observarem as carências emocionais e psicológicas dos usuários. O presente estudo avaliou a melhoria do conforto humano na Irmandade Santa Casa de Valinhos/SP-Brasil, proporcionado pela requalificação de áreas verdes existentes entre as alas de internação. Para avaliar o grau de conforto térmico proporcionado por essas áreas verdes requalificadas, utilizaram-se dois modelos preditivos de conforto: o Predicted Mean Vote - PMV (FANGER, 1970) e o Predicted Percentage of Disatisfied - PPD baseado na ISO 7730 (1994) para ambientes internos. A fim de se compararem os resultados obtidos com base nos modelos preditivos à percepção subjetiva do conforto térmico dos entrevistados, foram aplicados questionários contendo questões abertas e fechadas que possibilitaram uma análise dos benefícios terapêuticos proporcionados pelas áreas verdes requalificadas. Outro instrumento utilizado, o Inventário de Sintomas de Stress de LIPP, avaliou e comparou o nível de stress entre dois grupos de funcionários (com contato e sem contato com áreas verdes). Os resultados deste estudo demonstram que os espaços verdes requalificados, apesar de ainda não interferirem no grau de conforto térmico dos ambientes a eles adjacentes, cumprem um papel terapêutico na medida em que promovem maior bem-estar a todos que deles se usufruem. / In the first decades of the twentieth century, health professionals have invested into functional work environments, emphasizing the insertion of high-tech equipment and not concerned about the comfort provided by the physical environment. Scientific work in this area ranked these spaces as stressful and inappropriate in order not to observe the emotional and psychological necessities the users have. This study has evaluated the improvement of human comfort in Santa Casa de Valinhos / SP-Brazil, provided by the recovery of green areas between the internment wards at the hospital. To evaluate the thermal comfort degree provided by these recovered green areas, we have used two predictive comfort models: Predicted Mean Vote - PMV (FANGER, 1970) and Predicted Percentage of Disatisfied - PPD based on ISO 7730 (1994) for indoor environments. In order to compare the results based on predictive models to the subjective perception of the thermal comfort, questionnaires have been applied with open and closed questions which have allowed an analysis of therapeutic benefits provided by the recovered green areas. The other instrument used was Lipp Stress Symptom Inventory, which evaluated and compared the level of stress among two staff groups (with or without contact to the green areas). The results of this study have demonstrated that the recovered green spaces, while not influencing the thermal comfort degree of adjacent environments, which has a therapeutic role while promoting a greater well-being to all who enjoy them.
20

Neural correlates of affordance competition in dorsal premotor cortex

Pastor-Bernier, Alexandre 08 1900 (has links)
Le travail présenté dans cette thèse porte sur le rôle du cortex prémoteur dorsal (PMd) au sujet de la prise de décision (sélection d’une action parmis nombreux choix) et l'orientation visuelle des mouvements du bras. L’ouvrage décrit des expériences électrophysiologiques chez le singe éveillé (Macaca mulatta) permettant d’adresser une fraction importante des prédictions proposées par l'hypothèse des affordances concurrentes (Cisek, 2006; Cisek, 2007a). Cette hypothèse suggère que le choix de toute action est l’issue d'une concurrence entre les représentations internes des exigences et des atouts de chacune des options présentées (affordances; Gibson, 1979). Un intérêt particulier est donné au traitement de l'information spatiale et la valeur des options (expected value, EV) dans la prise de décisions. La première étude (article 1) explore la façon dont PMd reflète ces deux paramètres dans la période délai ainsi que de leur intéraction. La deuxième étude (article 2) explore le mécanisme de décision de façon plus détaillée et étend les résultats au cortex prémoteur ventral (PMv). Cette étude porte également sur la représentation spatiale et l’EV dans une perspective d'apprentissage. Dans un environnement nouveau les paramètres spatiaux des actions semblent être présents en tout temps dans PMd, malgré que la représentation de l’EV apparaît uniquement lorsque les animaux commencent à prendre des décisions éclairées au sujet de la valeur des options disponibles. La troisième étude (article 3) explore la façon dont PMd est impliqué aux “changements d'esprit“ dans un procès de décision. Cette étude décrit comment la sélection d’une action est mise à jour à la suite d'une instruction de mouvement (GO signal). I II Les résultats principaux des études sont reproduits par un modèle computationnel (Cisek, 2006) suggérant que la prise de décision entre plusieurs actions alternatives peux se faire par voie d’un mécanisme de concurrence (biased competition) qui aurait lieu dans la même région qui spécifie les actions. / This thesis examines the role of the dorsal premotor cortex (PMd) in the process of decision making (action selection) and visual guidance of arm movements. The work describes electrophysiological experiments conducted in awake monkeys (Macaca mulatta) and tests a number of important predictions suggested by the affordance competition hypothesis (Cisek, 2006; Cisek, 2007a). This hypothesis suggests that decisions can be viewed as the result of a competition between internal representations of conflicting demands and opportunities for actions or affordances (Gibson, 1979). Specific interest is given to the interaction between spatial information and expected value (EV) in a proposed affordance competition mechanism for action selection. The first study presented (article 1) explores how EV is represented during the delay period in PMd. This study also describes how this area reflects the spatial metrics of the options and examines the interaction between value and spatial information. The second study (article 2) explores the mechanism of action selection in more detail and extends the results to ventral premotor cortex (PMv). This study also addresses the nature of value and spatial representations from a learning perspective. In a novel environment the spatial metrics of the actions seem to be invariably present in PMd, meanwhile EV representations appear only once the animals make behaviorally informed decisions about the value of the available options. The third study (article 3) explores how PMd is involved in “changes of mind” in which action selection is updated following a movement instruction (GO signal). III IV The major findings in all these studies are reproduced by a computational model (Cisek, 2006) suggesting that decisions between actions can be made through a biased competition process that takes place in the same region that specifies the actions.

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