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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.
1

Application of PMV Fuzzy Control Algorithm in Pursuing Optimum Thermal Comfort

Fang, Wen-Hong 19 June 2012 (has links)
The exhausting fossil fuels have stimulated heating researches on alternative renewable energy, as well as energy friendly studies. In a country like Taiwan, with high density on population and buildings, fresh cold air are supplied by either fan-coil units or air-condition units. However, with the lack of intelligent control and poor justification on thermal comfort, these machines failed to provide optimal thermal comfort, a situation that always leads to "excessive control" and energy waste as a consequence. Optimal thermal comfort is pursued by using PMV fuzzy control theory, along with thermal comfort monitoring system derived from LabView icon-control software. Thermal Comfort indices such as Predicted Mean Vote (PMV) and Predicted Percent of Dissatisfied (PPD) according to the ISO 7730 are used as indicators of thermal comfort.Sensors, conscious of variations in humidity and temperatures, can figure out PMV and PPD via LabView Online Real Time calculation, and then we can control the environment comfort around PMV=1 next by using fuzzy control theory as well as energy efficient equipment such as AC stepless fans and AC stepless heaters. Many comfort simulation cases, comfort simulation with random humidity and temperatures, and a 12-hour automatic control, were presented as three testing items to check whether PMV FUZZY algorithm is competitive in fixing the environment thermal comfort around PMV=1. The confirmation of this question can be proved by this empirical study.
2

[en] ONLINE SHOPPING: WHY CONSUMERS GET DISSATISFIED? / [pt] COMPRAS ON-LINE: POR QUE OS COMPRADORES FICAM INSATISFEITOS?

MARCELO BARREIROS BARRETO 04 May 2010 (has links)
[pt] Esta dissertação tem como objetivo identificar nas compras on-line: por que os compradores ficam insatisfeitos, quais as razões principais das reclamações dos consumidores, através do site www.reclameaqui.com.br. Pelo canal Internet, o consumidor não só adquire, mas relata insatisfação com determinado produto/serviço, marca ou empresa. Comentários negativos na rede ganham amplitude quando comparados aos demais canais de comunicação. Foi feita a utilização do método de análise de conteúdo de 720 reclamações de consumidores, referentes a três empresas com mais reclamações no referido site. A coleta realizada de forma aleatória no período de um ano, de janeiro a dezembro de 2008, no maior site brasileiro destinado a reclamações de consumidores, o www.reclameaqui.com.br, possibilitou o agrupamento das queixas em 12 categorias. Das reclamações analisadas, grande parte é localizada em 5 categorias: falhas no serviço de atendimento ao pós-compra, de entrega, defeito no produto; quanto às políticas de devolução e de troca de produto. A causa principal de insatisfação é oriunda de falhas no serviço de atendimento pós-compra. Sob a ótica do consumidor on-line, o estudo identificou que as queixas analisadas são precedidas por tentativas infrutíferas de resolução junto aos canais de atendimento ao cliente. As descobertas sugerem que entender as categorias encontradas e suas interrelações pode ajudar as empresas a gerar estratégias de marketing, a fim de minimizar a intensidade e quantidade de reclamações, uma vez que estarão mais preparadas para solucioná-las. / [en] This dissertation has as object identify on online shopping: why consumers get dissatisfied, what are the main reasons of the consumers complains, through the www.reclameaqui.com.br website. On the internet channel, the consumer not only buys, but reports dissatisfaction with particular product/service, brand or company. Negative comments in the network are getting largeness when compared to other channels of communication. The method of content analysis was made by using 720 consumers’ complaints, related to three different companies with most complaints on the refered website. The collect were made randomly within one year period, from January to December 2008, on the largest Brazilian website, destined for consumer’s complaints, www.reclameaqui.com.br, enabling the grouping on complaints in 12 categories. Of the claims analyzed, much of it is located in 5 categories: failures in customer service after purchase, delivery, defective product, and the return policies and product exchange. The main cause of dissatisfaction is coming from failures in customer service after purchase. From the viewpoint of online consumers, the study identified that the analyzed complaints are preceded by unsuccessful attempts of resolution along the customer service channel. The results suggests aims to understand the categories found and their interrelation can help companies to create marketing strategies to minimize the intensity and amount of claims, since they will be better prepared to solve them.
3

Missnöjda kunders agerande : En jämförelse mellan köp i fysisk butik och i virtuell butik

Bohlin, Anna, Larsson, Viktoria January 2010 (has links)
<p>Inledning: Etableringen av e-handel har underlättat vardagen för många människor som nu kan handla produkter över internet, hemifrån och när de vill. Så länge som handel har funnits har även missnöjda kunder varit ett faktum och så länge handeln fortsätter kommer kunder fortsätta att vara missnöjda. E-handeln har gjort att många människor har fått nya shoppingvanor och värderingar, men en del är skeptiska till att handla över internet på grund av att det är krångligt och att de inte får den sinnliga upplevelsen det innebär att handla i en fysisk butik. Missnöjet som uppstår hos kunder som handlar över internet i en virtuell butik, tror vi skiljer sig från det missnöje en kund får efter att ha handlat i en fysisk butik.</p><p>Syfte: Syftet med uppsatsen är att från ett kundperspektiv utveckla en djupare förståelse för om missnöjda kunders agerande skiljer sig åt vid köp i en fysisk butik jämfört med köp i en virtuell butik. Om så är fallet så ska dessa skillnader beskrivas och analyseras för att ytterligare kunskap inom området ska uppnås. Senare ska rekommendationer ges till företag på hur de ska minska de hinder som kunder upplever vid köp i en fysisk och i en virtuell butik då de är missnöjda med en produkt.</p><p>Metod: Vi har genom en induktiv ansats samlat in empiri för att utveckla en djupare förståelse om kunders agerande vid missnöje. Då kunders agerande skulle studeras, ville vi tolka respondenternas ståndpunkter och vi valde att utgå från den kvalitativa metoden. Intervjuer gjordes med respondenter som någon gång hade handlat både i en fysisk butik och i en virtuell butik. De femton respondenterna valdes genom ett bekvämlighetsurval från åldersgruppen 25-34 år.</p><p>Teori: Teorierna vi presenterar består av konsumentbeteende, olika dimensioner av handel, relationsmarknadsföring, kundlojalitet och konsumentens bedömning av företagets kvalitet. Vi beskriver även orsakerna till varför en kund blir missnöjd och hur den agerar i en sådan situation, då vi anser att detta är relevant för att öka förståelsen för läsaren.</p><p>Resultat: För att få upprättelse för sitt missnöje har vi funnit att missnöjda kunder i en virtuell butik inte i samma utsträckning kontaktar butiken vid returnering som kunder i en fysisk butik gör. Förväntningarna på en köpt produkt i en virtuell butik är inte lika stora som produkter köpta i en fysisk butik, vilket påverkar agerandet vid missnöje.</p> / <p>The establishment of e-commerce has faciliated the daily routines for many people. Nowadays they can do purchases through internet, directly from their home and whenever they want. As long as trading has exist, dissatisfied customer has also been a fact and will be as long as we continue trading. New shopping habits and values come with e-commerce. Some customer are skeptical because of the missing sensual experience and because they estimate e-commerce complicated and problematic. We believed the customer dissatisfaction of a purchase through internet, differ from the customer dissatisfaction of a purchase done in a physical store.</p><p>Our purpose with the thesis is to increase the understanding if dissatisfied customer acts differ between purchases made in a physical store from purchases made in a virtual store. If that is the case we will describe and analyze the differences for further knowledge of the subject. Subsequent recommendations will be given to companies on how to reduce the barriers that customers experience when buying in a physical and a virtual store when they are unhappy with a product. For this study we applied a qualitative approach and accomplished fifteen interviews to get a deeper understanding of the customers’ point of view of the disaffected situations. The result presented shows, that unsatisfied customers to a virtual store do not contact the store in the same extent as customers to a physical store. Expectations of a purchased product in a virtual store are not equal to products purchased in a physical store, which affects the behaviour of discontent.</p>
4

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.
5

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
6

Missnöjda kunders agerande : En jämförelse mellan köp i fysisk butik och i virtuell butik

Bohlin, Anna, Larsson, Viktoria January 2010 (has links)
Inledning: Etableringen av e-handel har underlättat vardagen för många människor som nu kan handla produkter över internet, hemifrån och när de vill. Så länge som handel har funnits har även missnöjda kunder varit ett faktum och så länge handeln fortsätter kommer kunder fortsätta att vara missnöjda. E-handeln har gjort att många människor har fått nya shoppingvanor och värderingar, men en del är skeptiska till att handla över internet på grund av att det är krångligt och att de inte får den sinnliga upplevelsen det innebär att handla i en fysisk butik. Missnöjet som uppstår hos kunder som handlar över internet i en virtuell butik, tror vi skiljer sig från det missnöje en kund får efter att ha handlat i en fysisk butik. Syfte: Syftet med uppsatsen är att från ett kundperspektiv utveckla en djupare förståelse för om missnöjda kunders agerande skiljer sig åt vid köp i en fysisk butik jämfört med köp i en virtuell butik. Om så är fallet så ska dessa skillnader beskrivas och analyseras för att ytterligare kunskap inom området ska uppnås. Senare ska rekommendationer ges till företag på hur de ska minska de hinder som kunder upplever vid köp i en fysisk och i en virtuell butik då de är missnöjda med en produkt. Metod: Vi har genom en induktiv ansats samlat in empiri för att utveckla en djupare förståelse om kunders agerande vid missnöje. Då kunders agerande skulle studeras, ville vi tolka respondenternas ståndpunkter och vi valde att utgå från den kvalitativa metoden. Intervjuer gjordes med respondenter som någon gång hade handlat både i en fysisk butik och i en virtuell butik. De femton respondenterna valdes genom ett bekvämlighetsurval från åldersgruppen 25-34 år. Teori: Teorierna vi presenterar består av konsumentbeteende, olika dimensioner av handel, relationsmarknadsföring, kundlojalitet och konsumentens bedömning av företagets kvalitet. Vi beskriver även orsakerna till varför en kund blir missnöjd och hur den agerar i en sådan situation, då vi anser att detta är relevant för att öka förståelsen för läsaren. Resultat: För att få upprättelse för sitt missnöje har vi funnit att missnöjda kunder i en virtuell butik inte i samma utsträckning kontaktar butiken vid returnering som kunder i en fysisk butik gör. Förväntningarna på en köpt produkt i en virtuell butik är inte lika stora som produkter köpta i en fysisk butik, vilket påverkar agerandet vid missnöje. / The establishment of e-commerce has faciliated the daily routines for many people. Nowadays they can do purchases through internet, directly from their home and whenever they want. As long as trading has exist, dissatisfied customer has also been a fact and will be as long as we continue trading. New shopping habits and values come with e-commerce. Some customer are skeptical because of the missing sensual experience and because they estimate e-commerce complicated and problematic. We believed the customer dissatisfaction of a purchase through internet, differ from the customer dissatisfaction of a purchase done in a physical store. Our purpose with the thesis is to increase the understanding if dissatisfied customer acts differ between purchases made in a physical store from purchases made in a virtual store. If that is the case we will describe and analyze the differences for further knowledge of the subject. Subsequent recommendations will be given to companies on how to reduce the barriers that customers experience when buying in a physical and a virtual store when they are unhappy with a product. For this study we applied a qualitative approach and accomplished fifteen interviews to get a deeper understanding of the customers’ point of view of the disaffected situations. The result presented shows, that unsatisfied customers to a virtual store do not contact the store in the same extent as customers to a physical store. Expectations of a purchased product in a virtual store are not equal to products purchased in a physical store, which affects the behaviour of discontent.
7

Experimental investigation of ventilation performance of corner placed stratum ventilation in an office environment

Choonya, Gasper January 2019 (has links)
Energy use in buildings account for about one third of the total global energy supply and contributes as much as 30% of the anthropogenic greenhouse gas emissions. It is estimated that energy use in buildings will increase to 67% by 2030. The need for better thermal comfort and air quality in indoor environments is the leading cause for high energy use in buildings.  Heating, ventilation and air conditioning systems take up about 50% of the total energy use in buildings which is about 10-20% of the national energy use in most developed countries. The development and adoption of sustainable ventilation systems is a viable solution to mitigate climate change and curtail carbon emissions. The experimental study was conducted in a room resembling a modern office in a laboratory environment. The study involved investigating the ability of the system to provide cooling and heating. Concentration decay tracer gas technique using Sulphur hexafluoride (SF6) gas was used to determine the local air change index and air change efficiency in the room. Low-velocity omni-directional thermistor anemometer type CTA88 were used to measure the air velocity and temperature in the room. Smoke was used to visualise the flow patterns created in the room.  The climate chamber was used to mimic climatic conditions in winter. Fifteen cases were investigated with five air flow rates set points (30, 40, 50, 60 and 70 l/s) at three supply air temperatures, i.e., 17.6 °C, 21.0 °C and 25.3 °C. The results of the local air change index and air change efficiency for the nominal supply temperature of 17.6 °C showed that the system had strong characteristics of a mixing ventilation system. At the supply air temperature of 21.0 °C, the performance of the system deteriorated slightly to below that of a mixing ventilation system and could not satisfactorily provide heating at supply temperature of 25.3 °C. Better performance of the system at all supply air temperature setpoints was observed at lower airflow rates. At all supply air temperature setpoints, relatively higher degree of temperature stratification was observed at lower supply. The draught rate levels decreased with increase in supply air temperature and height. The location of the air inlet terminals in relation to the workstations had significant effect on the performance of the system. The stratum ventilation system did not work efficiently because the air streams were heavily mixed before reaching the occupants.

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