<p>Automatisk sparning i datorprogram undersöks från perspektivet hur användare upplever tryggheten till att deras arbete ska finnas kvar när de arbetar med en dator, och hur de reagerar på en ny typ av design. Det finns ett problem som ligger i hur datorer rent tekniskt är uppbyggda, jämfört med hur datoranvändare är vana att objekt fungerar i verkligheten. Nuvarande och gamla dator- program har tittats på för att se hur de har löst funktionerna kring sparning. Som teori för hur sparning förstås av dator- användare används mentala modeller och metaforer. Människans begränsningar hos minne och uppmärksamhet används för att förklara varför sparning bör skötas automatiskt. En serie undersökningar är gjorda som visar att den genomsnittlige dator- användaren idag anser sig lita på datorer till stor del när de arbetar med dem, samtidigt som de har beteenden som antyder att de inte litar på dem. Slutligen gjordes ett test med ett krånglande datorprogram som alltid bevarar användarens arbete. Dess resultat visar att datoranvändare kan lita på transparenta program som sparar i bakgrunden, utan att användaren märker någonting.</p>

The Directive 2002/91/EC of the European Parliament and Council on energy performance of buildings entered into force on 4th January 2003, setting the minimum requirements of energy performance. All Member States had to incorporate the requirements of the new directive in national legislation by January 2006 and build up relevant systems and measures to transpose and implement these requirements. The stage of Directive’s implementation in the countries of Southern Europe is reported because of the similar climatic conditions and the geographical location for a future enforcement in Greece, as the building code in Greece is still under development. As energy use in buildings accounts for about 40% of the final energy demand in the European Union, the application of building standards can achieve a reduction in electric energy consumption and therefore an increase in energy performance of buildings. A record of the electric energy consumption of office buildings in the four Prefectures of Crete is implemented aiming at a future energy saving, which may be obtained by either through increased efficiency or by reducing electric energy consumption.

This thesis consists of a summary and four self-contained papers. Paper [I] Following the 1987 report by The World Commission on Environment and Development, the genuine saving has come to play a key role in the context of sustainable development, and the World Bank regularly publishes numbers for genuine saving on a national basis. However, these numbers are typically calculated as if the tax system is non-distortionary. This paper presents an analogue to genuine saving in a second best economy, where the government raises revenue by means of distortionary taxation. We show how the social cost of public debt, which depends on the marginal excess burden, ought to be reflected in the genuine saving. We also illustrate by presenting calculations for Greece, Japan, Portugal, U.K., U.S. and OECD average, showing that the numbers published by the World Bank are likely to be biased and may even give incorrect information as to whether the economy is locally sustainable. Paper [II] This paper examines the relationships among per capita CO2 emissions, per capita GDP and international trade based on panel data spanning the period 1960-2008 for 150 countries. A distinction is also made between OECD and Non-OECD countries to capture the differences of this relationship between developed and developing economies. We apply panel unit root and cointegration tests, and estimate a panel error correction model. The results from the error correction model suggest that there are long-term relationships between the variables for the whole sample and for Non-OECD countries. Finally, Granger causality tests show that there is bi-directional short-term causality between per capita GDP and international trade for the whole sample and between per capita GDP and CO2 emissions for OECD countries. Paper [III] Fundamental questions in economics are why some regions are richer than others, why their growth rates differ, whether their growth rates tend to converge, and what key factors contribute to explain economic growth. This paper deals with the average income growth, net migration, and changes in unemployment rates at the municipal level in Sweden. The aim is to explore in depth the effects of possible underlying determinants with a particular focus on local policy variables. The analysis is based on a three-equation model. Our results show, among other things, that increases in the local public expenditure and income taxe rate have negative effects on subsequent income income growth. In addition, the results show conditional convergence, i.e. that the average income among the municipal residents tends to grow more rapidly in relatively poor local jurisdictions than in initially “richer” jurisdictions, conditional on the other explanatory variables. Paper [IV] This paper explores the relationship between income growth and income inequality using data at the municipal level in Sweden for the period 1992-2007. We estimate a fixed effects panel data growth model, where the within-municipality income inequality is one of the explanatory variables. Different inequality measures (Gini coefficient, top income shares, and measures of inequality in the lower and upper part of the income distribution) are examined. We find a positive and significant relationship between income growth and income inequality measured as the Gini coefficient and top income shares, respectively. In addition, while inequality in the upper part of the income distribution is positively associated with the income growth rate, inequality in the lower part of the income distribution seems to be negatively related to the income growth. Our findings also suggest that increased income inequality enhances growth more in municipalities with a high level of average income than in municipalities with a low level of average income.

Stora Enso Skoghalls Bruk är en av de största kartongtillverkarna på vår planet. Var sjätte kartongförpackning i världen som innehåller något flytande kommer från Skoghalls Bruk. Kartong har liten påverkan på miljön då huvudråvaran, trä, är en naturlig råvara. Kartong har många olika egenskaper och kan variera i utseende och styrka beroende på mängden fiber som använts vid tillverkningen. Kartong är dock inte i sig självt förseglingsbart men kan med hjälp av olika adhesiva material förseglas. Stora Enso tillverkar kartong på rullar som sedan skickas iväg till kund. Innan kartongrullarna skickas iväg packas de i skyddande kartong inför transporten. Denna packning kallas emballering.Syftet med denna studie var att tidseffektivisera emballeringsprocessen. Stora Enso har i dagsläget en överkapacitet i emballeringsprocessen och processen är en trång sektion för produktionen. Delprocessen gavelpressen har studerats då den är mer tidskrävande än omkringliggande delprocesser. När kartongrullarna kommer till gavelpressen tillsätts det sista emballaget. Kartongrullarna har innan emballerats med innerrondeller på gavlarna och mantelomslag runt om. Gavelpressen består av två värmeplattor med tillsatta ytterrondeller. Värmeplattornas uppgift är att försegla kartongrullarna genom att det yttersta lagret, LDPE-skiktet, på ytterrondellerna smälts fast på kartongrullarna. Värmeplattorna har temperaturen 180 °C och rör sig mot kartongrullens gavlar i tre olika hastigheter som gradvis sänks ju närmare kartongrullen de kommer. För att sedan under en tid av sju sekunder pressa ytterrondellerna mot kartongrullens gavlar.Målet med denna studie var att tidseffektivisera gavelpressen samt ta fram en rekommendation för i vilken ordning åtgärderna bör hanteras. Simuleringsprogrammet COMSOL Multiphysics har använts för att bygga upp systemet, simulera verkliga fall och sedan effektivisera dem genom att minska delprocessens cykeltid. Tiden som ytterrondellerna pressas mot kartongrullens gavlar studerades i en 3D-modell. För att ta reda på om presstiden var den mest optimala simulerades temperaturen på kartongrullens gavels yttersta skikt vid pressning. Värmeöverföringen mellan ytterrondellens LDPE-skikt och kartongrullen antogs öka ända tills kartongrullens gavels yttersta skikt uppnått värmeplattans temperatur 180 °C. Vidare studerades om LDPE-skiktet kunde bytas ut mot ett material som gör att värmeöverföringen sker snabbare. Densitet, specifik värmekapacitet och termisk konduktivitet var de faktorer som ändrades. Värmeplattornas maximala hastighet studerades genom beräkningar. Luften mellan värmeplattan och kartongrullen antogs ha en cylindrisk form och luftens hastighet ut ur cylindern beräknades med hjälp av Reynolds tal. Värmeplattans hastighet antogs kunna öka så länge luftflödet var laminärt. Det undersöktes även om värmeplattornas rörelse kunde starta tidigare, då de studerade kartongrullarna står stilla med tillsatta ytterrondeller under olika lång tid innan värmeplattorna börjar röra sig.För att tidseffektivisera gavelpressen rekommenderas fyra åtgärder i följande ordning: minska presstiden, starta värmeplattornas rörelse tidigare, byta ut LDPE-skiktet samt öka värmeplattornas hastighet. Åtgärderna har rekommenderats i ordning efter vad som antagits vara enklast och minst tidskrävande för företaget.Simuleringarna visade att presstiden kan minskas till 3-3,5 sekunder då ingen ökad värmeöverföring sker mellan värmeplattan och kartongrullen efter denna tid. Denna åtgärd ger en tidsbesparing på 3,5-4 sekunder. Att starta värmeplattornas rörelse tidigare är möjligt, då värmeplattorna med tillsatta ytterrondeller står redo 3,35–9,33 sekunder innan de sätts i rörelse. Företaget rekommenderas att starta värmeplattornas rörelse efter 3,35 sekunder oavsett kartongrullens bredd. Detta kan ge en tidsbesparing på upp till 5,98 sekunder.Det rekommenderas att byta ut LDPE-skiktet mot ett material med högre termisk konduktivitet och densitet, men med liknande adhesiva egenskaper. En sekunds tidsbesparing kan fås om den termiska konduktiviteten ändras från 0,33 till 0,5 W/mK samtidigt som densiteten ändras från 605 till 800 kg/m3.Beräkningar av luftens hastighet visade att den maximala hastighet som värmeplattan kan ha var 16,37 m/s på ett avstånd 1700 mm från kartongrullen. Att utföra denna åtgärd kräver en omprogrammering av värmeplattornas rörelse från tre hastighetssteg till en hastighet som hela tiden minskar allt eftersom avståndet mellan värmeplattorna och kartongrullen minskar. Detta är den sista åtgärd som rekommenderas eftersom den antas vara mest krävande för företaget och en ombyggnation kan eventuellt behövas. Värmeplattornas beräknade maximala hastighet är ca 40 gånger större än den snabba hastigheten som värmeplattorna har i dagsläget och därför bör företaget kunna öka den snabba hastigheten och medel hastigheten. Fyra sekunder är den optimala tidsbesparingen för att undvika väntetid mellan delstationerna innan och efter gavelpressen. Med de hastigheter som beräknats vara möjliga för värmeplattorna kan med enkelhet en tidsbesparing på fyra sekunder uppnås.Om samtliga åtgärder görs fås en tidsbesparing på ca 15 sekunder. Då fyra sekunder är den optimala tidsbesparingen kan företaget välja vilka åtgärder som ska göras och i hur stor utsträckning. En tidsbesparing på fyra sekunder innebär att gavelpressens cykeltid minskar med 12-13 % samtidigt som produktionskapaciteten ökar i samma takt. / Stora Enso Skoghall Mill is one of the world’s greatest manufacturers of paperboard. Every six paperboard package containing a liquid is made at Skoghall Mill. Paperboard has a small environmental impact since the main product, wood, is a natural source. Paperboard can have many different properties and vary in appearance and strength depending on the amount of fiber used in manufacture. Paperboard is not sealable by itself but can, with other adhesive materials be sealed. Stora Enso is producing paperboard on rolls which later are sent off to the customers. Before they sent them to the customers, the rolls are packed in protective paperboard before transportation. This process is called the packaging process.The purpose of this study was to make the packaging process more time efficient. Stora Enso currently has an overcapacity in the packaging process and the process is a bottleneck for the production. The process end press has been studied since it was more time consuming than surrounded processes. When the paperboard rolls enter the end press, the last packaging is added. The paperboard rolls has earlier been wrapped with inner pads on the ends and cover around. The end press consists of two heated plates with outer pads added. The heated plates purpose are to seal the paperboard rolls by melting the outer layer of the outer pad, the LDPE layer, to the paperboard rolls ends. The heated plates temperature is fixed at 180 °C and the plates are moving towards the paperboard rolls with three different velocities which are gradually decreased the closer the heated plates gets to the paperboard rolls. For later during seven seconds pressing the outer pads to the paperboard rolls ends.The goal with this study was to make the end press more time efficient and make a recommendation in which way the improvements should be handled. The simulation software COMSOL Multiphysics has been used to build the system, simulate the real cases and then making them more time efficient by decreasing the cycle time. The time in which the outer pads are pressed to the paperboard rolls ends was studied in a 3D-model. To find out if the pressing time was the most optimal, the temperature on the paperboard rolls ends outer layer was simulated during pressing. The heat transfer between the LDPE-layer of the outer pad and the paperboard roll were assumed to increase until the paperboard rolls ends reached the temperature of the heated plates 180 °C. Later, it was studied if the LDPE-layer could be replaced by a material which makes the heat conduction go faster. Density, specific heat capacity and thermal conductivity were factors which were varied. The maximum velocities of the heated plates were studied by calculations. The air between the heated plate and the paperboard roll were assumed to have a cylindrical shape and the air flow through the cylinder was calculated by the Reynolds number. The velocity of the heated plates was assumed to be increased as long as the air flow was laminar. It was also examined if the movement of the heated plates could begin earlier since the heated plates with added outer pads are standing still under different time before the heated plates start moving.To make the end press more time efficient, four improvements are recommended as follows: decrease the pressing time, start the movement of the heated plates earlier, replace the LDPE-layer and increase the velocity of the heated plates. The improvements are recommended in order of what was assumed to be easiest and least time consuming for the company.The simulations showed that the pressing time can be decreased to 3-3.5 seconds since no heat transfer occurred between the heated plates and the paperboard roll after this time. This improvement provides a time saving of 3.5-4 seconds. To start the movement of the heated plates earlier was possible since they are standing still with added outer pads 3.35-9.33 seconds before the movement starts. The company is recommended to start the movement of the heated plates after 3.35 seconds regardless of the width of the paperboard rolls. This improvement could save up to 5.98 seconds.It is recommended to replace the LDPE-layer by a material with higher thermal conductivity and density, but with similar adhesive properties. A time saving of one second can be done if the thermal conductivity is changed from 0.33 to 0.5 W/mK at the same time as the density is changed from 605 to 800 kg/m3.Calculations of the air flow showed that the maximum velocity of the heated plates was 16.37 m/s at the distance 1700 mm from the paperboard roll. To make this improvement, a reprogramming of the heated plates movement is required, from three velocity stages to one velocity which decrease as the distance between the heated plates and the paperboard roll decrease. This is the last recommended improvement since it is believed to be the most challenging one for the company and a reconstruction may be needed. The calculated maximum velocity of the heated plates was about 40 times greater than the fast velocity of the heated plates today and therefore the company should be able to increase the fast velocity and the medium velocity. Four seconds is the optimal time saving to avoid waiting time between the sub processes before and after the end press. A time saving of four seconds could easily be done by using the calculated maximum velocities.If all improvements are done a time saving of 15 seconds can be made. Since the optimal time saving is four seconds, the company can choose which improvements that should be done and in which extent. A time saving of four seconds means that the cycle time of the end press is reduced by 12-13 %, while the production capacity increase with same rate.

För att hålla ett behagligt inomhusklimat på fartyg krävs kylning under den varma tiden på året. Denna kylning kräver energi. Detta arbete är en undersökning om huruvida denna energiåtgång kan minskas genom så kallad frikylning. ROPAX-färjan Finntrader som trafikerar linjen Malmö–Travemünde har använts som exempel. Undersökningen utfördes genom att skapa en beräkningsmodell där ett köldbärarsystem med möjlighet till frikylning kopplades in i Finntraders nuvarande HVAC-system, tillsammans med nuvarande kylmaskiner. Statistik över lufttemperatur, luftfuktighet och sjövattentemperatur för perioden 2013–2015 införskaffades. Denna statistik fördes in i beräkningsmodellen. Resultatet av beräkningarna blev att en viss mängd energi kunde sparas med frikylning, hur mycket beroende på värmeväxlarnas effektivitet. Mängden energi som kunde sparas var förhållandevis liten jämfört med kostnaden för de komponenter modellen krävde. / To maintain a comfortable climate on board ships, cooling is necessary during the warm period of the year which requires energy. This thesis is a survey about whether so-called free cooling could reduce this energy consumption. The ROPAX-ferry Finntrader trafficking the route Malmö–Travemünde has been used as an example. This survey was carried out by creating a calculation model in which a brine system with a possibility of free cooling was connected to Finntrader’s current HVAC-system, alongside the current chillers. Statistics of air temperature, air humidity and sea water temperature was acquired for the period 2013-2015 and were inserted into the calculation model. These calculations showed that a certain amount ofenergy could be saved with free cooling, how much depending on the effectiveness of the heat exchangers. The amount of energy that could be saved was quite small compared to the cost of the components required by the model.

Industry is one of the major energy consumers resulting in negative environmental impacts in the world. In this context, industrial energy management becomes critically important when improving industrial energy savings. Emphasized is the careful energy treatment in the Sustainable Development Goals of the United Nations. The dominance of a technical approach in current research of industrial energy management suppresses significant potentials of human behavior for energy efficiency. Societal problems such as the energy efficiency gap and the rebound effect may be tackled by involving energysaving behavior in interventions. This thesis aims to explain characteristics of energy-saving behavior in the industrial settings of an automobile producer in Central Europe. The manufacturer utilizes an energy management program, named QUEST, which is facilitated by the external advisor HE Consulting s.r.o. Questions of particular interest are therefore related to perceived organizational readiness to engage in energy-saving behavior. Data gathering include a structured-questionnaire of perceptions on energy savings at the plants with managers of the automobile producer. Additionally, a semi-structured interview with the CEO of HE Consulting s.r.o. offers a more in-depth view on practical implications of energysaving behavior. As a base for data collection serves a psychological perspective of perceptional theories. Strongly related is that approach to the change management discipline. Results of the study show that, indeed, managers in the QUEST program tend to perceive organizational readiness on energy savings re latively more positive than managers outside the program. Resistance to change can be marginally observed in lower management levels. However, the managers emphasize a lack of time to engage in energy savings. Indicators of perceived organizational readiness on energy savings alone do not show the actual energy-saving behavior. This means that this thesis does not directly observe energy-saving behavior. Nevertheless, the impact of such indicators on the actual performed energy-saving behavior may be seen in combination with quantified energy savings. All findings can only be interpreted in the frame of this study.

Sustainability has been at the centre of global attention for decades. One of the most challenging areas toward sustainability is the agricultural sector. Here, the commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times higher than for open land farming. However, this improvement comes with a higher energy demand. Therefore, the significance of energy conservation and management in the commercial greenhouse has been emphasized to enable cost efficient crop production. This Doctoral Thesis presents an assessment of energy pathways for improved greenhouse performance by reducing the direct energy inputs and by conserving energy throughout the system. A reference theoretical model for analyzing the energy performance of a greenhouse has been developed using TRNSYS. This model is verified using real data from a conventional greenhouse in Stockholm (Ulriksdal). With this, a number of energy saving opportunities (e.g. double glazing) were assessed one by one with regards to the impact on the annual heating, cooling and electricity demand. Later, a multidimensional energy saving method, the “Closed Greenhouse”, was introduced. The closed greenhouse is an innovative concept with a combination of many energy saving opportunities. In the ideal closed greenhouse configuration, there are no ventilation windows, and the excess heat, in both sensible and latent forms, needs to be stored using a seasonal thermal energy storage. A short term (daily) storage can be used to eliminate the daily mismatch in the heating and cooling demand as well as handling the hourly fluctuations in the demand. The key conclusion form this work is that the innovative concept “closed greenhouse” can be cost-effective, independent of fossil fuel and technically feasible regardless of climate condition. For the Nordic climate case of Sweden, more than 800 GWh can be saved annually, by converting all conventional greenhouses into this concept. Climate change mitigation will follow, as a key impact towards sustainability. In more detail, the results show that the annual heating demand in an ideal closed greenhouse can be reduced to 60 kWhm-2 as compared to 300 kWhm-2 in the conventional greenhouse. However, by considering semi-closed or partly closed greenhouse concepts, practical implementation appears advantageous. The required external energy input for heating purpose can still be reduced by 25% to 75% depending on the fraction of closed area. The payback period time for the investment in a closed greenhouse varies between 5 and 8 years depending on the thermal energy storage design conditions. Thus, the closed greenhouse concept has the potential to be cost effective. Following these results, energy management pathways have been examined based on the proposed thermo-economic assessment. From this, it is clear that the main differences between the suggested scenarios are the type of energy source, as well as the cooling and dehumidification strategies judged feasible, and that these are very much dependent on the climatic conditions Finally, by proposing the “solar blind” concept as an active system, the surplus solar radiation can be absorbed by PVT panels and stored in thermal energy storage for supplying a portion of the greenhouse heating demand. In this concept, the annual external energy input for heating purpose in a commercial closed greenhouse with solar blind is reduced by 80%, down to 62 kWhm-2 (per unit of greenhouse area), as compared to a conventional configuration. Also the annual total useful heat gain and electricity generation, per unit of greenhouse area, by the solar blind in this concept is around 20 kWhm-2 and 80 kWhm-2, respectively. The generated electricity can be used for supplying the greenhouse power demand for artificial lighting and other devices. Typically, the electricity demand for a commercial greenhouse is about 170 kWhm-2. Here, the effect of “shading” on the crop yield is not considered, and would have to be carefully assessed in each case. / Hållbarhet har legat i fokus under decennier. En av de mest utmanande områdena är jordbrukssektorn, där. kommersiella växthus är ett av de mest effektiva odlingsalternativen med en avkastning per odlad yta upp till 10 gånger högre än för jordbruk på friland. Dock kommer denna förbättring med ett högre energibehov. Därför är energieffektivisering i kommersiella växthus viktig för att möjliggöra kostnadseffektiv odling. Denna doktorsavhandling presenterar en utvärdering av olika energiscenarios för förbättring av växthusens prestanda genom att minska extern energitillförsel och spara energi genom i systemet som helhet. För studien har en teoretisk modell för analys av energiprestanda i ett växthus utvecklats med hjälp av TRNSYS. Denna modell har verifierats med hjälp av verkliga data från ett konventionellt växthus i Stockholm (Ulriksdal). Med denna modell har ett antal energibesparingsåtgärder (som dubbelglas) bedömts med hänsyn till de totala värme-, kyl-och elbehoven. En flerdimensionell metod för energibesparing, det s.k. "slutna växthuset", introduceras. Det slutna växthuset är ett innovativt koncept som är en kombination av flera energibesparingsmöjligheter. I den ideala slutna växthuskonfigurationen finns det inga ventilationsfönster och värmeöverskott, både sensibel och latent, lagras i ett energilager för senare användning. Daglig lagring kan användas för att eliminera den dagliga obalansen i värme-och kylbehovet. Ett säsongslager introduceras för att möjliggöra användandet av sommarvärme för uppvärmning vintertid. Den viktigaste slutsatsen från detta arbete är att ett sådant innovativt koncept, det "slutna växthuset" kan vara kostnadseffektiv, oberoende av fossila bränslen och tekniskt genomförbart oavsett klimatförhållanden. För det svenska klimatet kan mer än 800 GWh sparas årligen, genom att konvertera alla vanliga växthus till detta koncept. Det årliga värmebehovet i ett idealiskt slutet växthus kan reduceras till 60 kWhm-2 jämfört med 300 kWhm-2 i ett konventionellt växthus. Energibesparingen kommer även att minska miljöpåverkan. Även ett delvis slutet växthus, där en del av ytan är slutet, eller där viss kontrollerad ventilation medges, minskar energibehovet samtidigt som praktiska fördelar har kunnat påvisas. Ett delvis slutet växthus kan minska energibehovet för uppvärmning med mellan 25% och 75% beroende på andelen sluten yta. En framräknad återbetalningstid för investeringen i ett slutet växthus varierar mellan 5 och 8 år beroende på design av energilagringssystemet. Sålunda har det slutna växthuskonceptet potential att vara kostnadseffektiv. Mot bakgrund av dessa lovande resultat har sedan scenarios för energy management analyserats med hänsyn till termo-ekonomiska faktorer. Från detta är det tydligt att de viktigaste skillnaderna mellan de föreslagna scenarierna är den typ av energikälla, samt kyl- och avfuktningsstrategier som används, och dessa val är mycket beroende av klimatförhållandena. Slutligen, föreslås ett nytt koncept, en s.k. "solpersienn", vilket är ett aktivt system där överskottet av solstrålningen absorberas av PVT-paneler och lagras i termiskenergilager för att tillföra en del av växthuseffekten värmebehov. I detta koncept minskar den årliga externa energitillförseln för uppvärmning i ett slutet växthus med 80%, ner till 62 kWhm-2. Den totala värme- och elproduktionen, med konceptet "solpersienn" blir cirka 20 kWhm-2 respektive 80 kWhm-2. Elproduktion kan användas för artificiell belysning och annan elektrisk utrustning i växthuset. / <p>QC 20130910</p>

L'industrie de la pêche est confrontée à plusieurs contraintes comme l'augmentation du prix du carburant et la diminution des stocks de poisson. Pour améliorer la rentabilité, nous avons fait l'optimisation des chaluts de pêche (pélagique et de fond) afin d'augmenter leurs efficacités énergétiques. Deux facteurs principaux ont été utilisés : la traînée du chalut et sa surface balayée. Notre travail porte sur l'optimisation du plan du chalut par modification du nombre de mailles des pièces du filet et par changement de la longueur des câbles. Nous avons développé une méthode de recherche successive appelée SOT et nous l'avons comparée à une méthode de recherche aléatoire dans le cas d'un chalut pélagique avec un gain net de 54%. La SOT a été utilisée pour optimiser le plan des pièces du filet d'un chalut de fond. Une amélioration du gain énergétique de 38% a été obtenue, ainsi qu'une réduction de 45 jours de pêche. Par souci de risque de baisse de capturabilité, nous avons développé une fonction objectif qui dépend de la distribution de poisson. Trois fonctions de même densité surfacique ont été testées. L'amélioration de l'efficacité énergétique calculée par la méthode SOT sur un chalut de fond est respectivement de 52%, 16% et 32% selon les trois distributions. Avec la méthode SRT (méthode de raffinement séquentiel), nous obtenons des réductions de 56%, 30% et 39% pour les trois distributions. Finalement nous avons adapté la méthode SOT pour optimiser les longueurs des câbles du chalut. Nous obtenons dans un cas une amélioration de l'efficacité énergétique de 49%. L'utilité de ce travail devrait être étendue hors de la pêche comme l'écologie en général. / Nowadays, fishing industry is facing several constraints such as increased fuel prices and declining fish stocks. In this work, we perform optimization of fishing trawls (pelagic and bottom) in order to improve their energy efficiencies. Two main factors were used: the trawl drag and its mouth swept area. Our work focuses on optimizing trawl design by altering mesh numbers and changing cable length. We have developed a method called SOT and compared it to a random search method in the pelagic trawl case with a net energy gain of 54%. The SOT was used in design optimization of bottom trawl panels. Improved energy gain of 38% was obtained and a reduction of 45 total number of fishing days. In order to bypass catchability reduction, we developed an objective function which depends on fish distribution. Three functions with same bottom surface density were tested. Improving energy efficiency calculated by the SOT method on a bottom trawl is respectively 52%, 16% and 32% for the three distributions. With the SRT method (sequential refinement), we obtain reductions of 56%, 30% and 39% for the three aforementioned distributions. Finally we adapted the SOT method to optimize trawl cable lengths. In one case, we obtain energy efficiency improved by 49%. The usefulness of this work should be extended beyond fishery to ecology in general.

Dans le cadre des réseaux ad hoc à grande envergure, le concept de clusterisation peut être mis à profit afin de faire face aux problèmes de passage à l'échelle et d'accroître les performances du système. Tout d’abord, cette thèse présente notre algorithme de clusterisation TBCA ‘Tiered based Clustering algorithm’, ayant pour objectif d’organiser le processus de clusterisation en couches et de réduire au maximum le trafic de contrôle associé à la phase d’établissement et de maintenance de l’infrastructure virtuelle générée. La formation et la maintenance d’une infrastructure virtuelle ne sont pas une fin en soi. Dans cet axe, on a exploité les apports de notre mécanisme de clusterisation conjointement avec le mode veille, à travers la proposition de l’approche de conservation d’énergie baptisée CPPCM ‘Cluster based Prioritized Power Conservation Mechanism’ avec deux variantes. Notre objectif principal est de réduire la consommation d’énergie tout en assurant l’acheminement des paquets de données sans endurer des temps d’attente importants aux niveaux des files d’attente des nœuds impliqués dans le transfert. Nous avons proposé aussi un algorithme de routage LCR ‘Layered Cluster based Routing’ se basant sur l’existence d’une infrastructure virtuelle. L’exploitation des apports de notre mécanisme TBCA et la limitation des tâches de routage additionnelles à un sous ensemble de nœuds sont des atouts pour assurer le passage à l’échelle de notre algorithme. / Relying on a virtual infrastructure seems a promising approach to overcome the scalability problem in large scale ad hoc networks. First, we propose a clustering mechanism, TBCA ‘Tiered based Clustering algorithm’, operating in a layered manner and exploiting the eventual collision to accelerate the clustering process. Our mechanism does not necessitate any type of neighbourhood knowledge, trying to alleviate the network from some control messages exchanged during the clustering and maintenance process. Since the energy consumption is still a critical issue, we combining a clustering technique and the power saving mode in order to conserve energy without affecting network performance. The main contribution of our power saving approach lies on the differentiation among packets based on the amount of network resources they have been so far consumed. Besides, the proposed structure of the beacon interval can be adjusted dynamically and locally by each node according to its own specific requirements. We propose also a routing algorithm, LCR ‘Layered Cluster based Routing’. The basic idea consists on assigning additional tasks to a limited set of dominating nodes, satisfying specific requirements while exploiting the benefits of our clustering algorithm TBCA.

Doctor of Philosophy / School of Family Studies and Human Services / Kristy L. Pederson-Archuleta / Martin Seay / This dissertation employed a psychological framework to investigate the saving behavior of older pre-retirees through three essays using data from the Health and Retirement Study (HRS). Understanding the connection between psychological characteristics and saving behavior is critical as this population attempts to bridge the retirement saving gap. Of these characteristics, financial self-efficacy beliefs (FSE) are theoretically vital to saving behavior. With the FSE beliefs of older adults weak and vulnerable to decline, more research is needed to understand how FSE beliefs affect saving behavior and how FSE beliefs can be supported. Essay one investigated the psychological characteristics associated with FSE beliefs according to the Meta-Theoretic Model of Motivation and Personality (3M). Using a sample of 2,070 pre-retirees aged 50 to 70, essay one revealed that FSE beliefs can be supported through the frequent experience of positive affect, reduced negative affect, a stronger perception of mastery, and a higher task orientation, holding all else constant. Essay two investigated the relationship between FSE beliefs and saving behavior (i.e., change in net worth from 2008 to 2012) through the Social Cognitive Theory of Self-Regulation. Using a sample of 844 pre-retirees aged 50 to 70, results revealed that FSE beliefs are significantly and positively related to saving behavior, after controlling for the financial ability and motivation to save. Essay three employed a structural equation model to investigate an integrated psychological approach to saving behavior based upon the 3M. Using a sample of 1,370 pre-retired and partially retired adults aged 50 to 70, essay three revealed that FSE beliefs facilitated the connection between elemental traits (i.e., openness, conscientiousness, extroversion, agreeableness, and neuroticism), compound traits (i.e., positive affect, negative affect, mastery, and task orientation), and saving behavior. Overall, significant evidence was generated supporting a psychological approach to the saving behavior of older pre-retirees. Financial and mental health professionals can utilize this framework to provide holistic retirement saving advice that acknowledges the psychological roots of behavior. Moreover, results established empirical support for the role FSE beliefs play in executing saving behavior. Lastly, results supported the importance of domain specific measurement for self-efficacy beliefs in future research.