Dissertations / Theses on the topic 'Cycles'
To see the other types of publications on this topic, follow the link: Cycles.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Cycles.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Houriet-Segard, Geneviève. "Logement, cycles démographiques et cycle de vie." Paris, Institut d'études politiques, 1998. http://www.theses.fr/1998IEPP0029.
Full textAbstract:
Cette thèse comprend trois approches du marché du logement dont l'objectif est de saisir les interactions entre démographie et logement. 1. Analyse de l'influence des cycles démographiques sur la demande agrégée de logement : une revue de modèles macroéconomiques de marché du logement incluant un déterminant démographique est présentée, puis une modélisation du marché du logement est effectuée sur la base de données économiques françaises. L'hypothèse majeure de ce modèle est l'idée d'un surplus systématique d'offre de logement par rapport à la demande dont l'ampleur détermine le prix. Enfin, ce modèle est simulé selon différents scenarios démographiques et économiques. 2. Analyse des déterminants démographiques des choix individuels de logement : le but est de déceler une éventuelle logique de cycle de vie dans les comportements résidentiels des ménages avec acquisition d'un logement pendant la période d'activité et désaccumulation pendant la retraite. Ces comportements sont testés sur l'enquête logement 92: la consommation de logement, le statut d'occupation et la mobilité sont analyses. 3. Microsimulation du marché du logement qui permet d'étudier les interactions entre le vieillissement de la population, le marché du logement et les transferts intergénérationnels (legs et système de retraite) : le modèle considère une population hétérogène ou les individus naissent, ont des enfants, vieillissent et meurent, reçoivent des salaires ou retraites et bénéficient parfois d'un héritage. Chaque agent vit une ou deux périodes pendant lesquelles il optimise sa consommation selon les principes de la théorie du cycle de vie généralisée. Alors que l'on se retrouve à chaque période avec une population d'individus aux caractéristiques différentes, le bouclage macroéconomique du modèle met en place un système de prix qui assure la cohérence comptable des comportements. Ce modèle est enfin simulé afin d'analyser les effets de différents chocs démographiques et évolutions économiquesThis thesis includes three parts. It's objective is to better understanding interactions between demography and housing. Analysis of the demographic cycles influencing the housing demand and the housing market equilibrium: some existing housing market's models with a demographic determinant are reviewed. Such a model is then built up based on French economical data. The model's main hypothesis is that there is a systematic excess of housing supply over demand. The level of this excess has a direct incidence on the price of housing. This model is simulated using various demographic and economical scenarios. Analysis of residential choices during the life cycle: the focus is the household's housing behavior with the saving's life cycle theory (e. G. People buy a house when they are working and sell it when they are retire to compensate the loss of revenue and to maintain the same level of consumption). These behaviors are tested on the data of the French survey "enquete logement 92". Behaviors such as the housing consumption, the tenure choice and the mobility of elder householders are tested in the context of saving's life cycle theory. Microsimulation of the housing market that allows the study of the interactions between aging population, the housing market and intergenerational transfers (bequests and social security programs): at the microeconomic level, this model takes into account a heterogeneous population simulating events such as birth's and death's dates, salary, retirement pension and sometimes inheritances. All people live two periods in their lifetime where they will optimize their consumption following the generalized saving's life cycle theory. Lastly, individual behaviors are aggregated and compiled at a macroeconomic level. This model is also simulated for different demographic and economical evolutions
2
Csabafi, Tamas Zoltan. "Business cycles, endogenous growth, and monetary cycles." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/88965/.
Full textAbstract:
This dissertation sets out to introduce a new calibration procedure building on Jermann (1998) and the iterative shock identification scheme of Benk et al. (2005) in Chapter 1. It incorporates the use of Simulated Annealing, a global optimization algorithm, into the Jermann (1998) calibration methodology that is applied to search for the combination of structural parameters within a bounded parameter space that yields the lowest distance between a vector of US data moments and its simulated moments counterpart in the frequency domain. It also extends the methodology of Jermann (1998) with the identification scheme of Benk et al. (2005) to obtain convergent estimates for shock parameters. After illustrating the workings of this new calibration methodology on the two sector business cycle model of Dang et al. (2011) with endogenous growth and human capital in Chapter 2 this dissertation sets out in Chapter 3 to introduce an extended version of the model of Dang et al. (2011) and to explain a number of real business cycle (RBC) problems that include the Gali (1999) labor response, the basic consumption-output and labor-output relationship, and the lack of an internal propagation mechanism as pointed out by Cogley and Nason (1995) and Rotemberg and Woodford (1996). This extension follows the suggestions of King and Rebelo (2000) to incorporate an external labor margin through a human capital investment sector and a physical capital utilization margin in the form of physical capital utilization rate to improve the performance of the standard RBC model. In the model introduced in Chapter 3 the physical capital utilization rate is further amended by the introduction of entrepreneurial capacity as in Friedman (1976) and Lucas (1988). The added margin of physical capital utilization is intra-temporal in nature, which enables the new calibration scheme to improve on the ability of the model significantly to explain the underlying real business cycle problems and US data moments in the frequency domain. Lastly, in Chapter 4 a simple monetary extension of the model in Chapter 3 is presented. In this chapter it is shown that the added physical capital utilization in a monetary model combined with the proposed calibration scheme is successful in explaining the empirical negative long term relationship between in ation and output.
3
Ash, Patricia. "Dominating cycles, Hamilton cycles and cycles with many chords in 2-connected graphs." Thesis, Goldsmiths College (University of London), 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490379.
Full text
4
Doare-Michel, Nola. "Relations entre cycle de développement familial et cycles d'identité." Université Claude Bernard - Lyon I, 1994. http://www.theses.fr/1994LYO1M292.
Full text
5
Wallestad, Kate. "Growing Cycles." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3330.
Full textAbstract:
In my paintings and prints, I create to understand my experiences. I make layered, repetitive marks and gestures that consist of spherical masses, orbits, and cellular forms. The shapes represent aspects of reproduction and symbolize my thoughts and ideas about procreation. In making pieces, I employ a mathematical system that describes growth patterns found in nature. I use this system as a way of echoing natural structures, as well as a way of focusing my attention. I create multiple small pieces and present them in large, gridded formats. These pieces are abstracted narratives of my thoughts and feelings.
6
Champion, Olivier-David. "Cycles d'investissements et cycles électoraux dans les communes françaises." Montpellier 1, 1996. http://www.theses.fr/1996MON10052.
Full textAbstract:
Cette thèse a pour objectif la construction d'un modèle comportemental expliquant les différents faits stylisés observés dans la gestion des communes françaises. Cette construction s'articule autour d'une structure inter-temporelle à deux périodes considérées respectivement comme non électorale et électorale. La maximisation de la probabilité de vote s'effectue sous les contraintes légales de gestion auxquelles sont soumis les élus municipaux. La pratique du cycle électoral se caractérise alors par une forte poussée des investissements et de la pression fiscale à la première période puis d'un net ralentissement de la valeur de ces mêmes variables lors de la deuxième période (période au cours de laquelle se déroule le scrutin). Le modèle est présenté sous une forme croissante de complexité grâce à un relâchement progressif des hypothèses et il permet de reproduire le même schéma de gestion dans chacune des situations envisagées. Nous avons alors généralise ce "comportement électoraliste" en considérant les scrutins successifs. Notre travail s'arrête alors sur la possibilité de nouvelles stratégies de gestion, stratégies permettant de poursuivre des objectifs autres qu'une maximisation de la probabilité de vote au terme du mandat. Ces stratégies peuvent alors s'inscrire dans un jeux séquentiel.
7
Brunner, Benjamin. "The sulfur cycle: from bacterial microenvironment to global biogeochemical cycles /." Zürich : [s.n.], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15197.
Full text
8
Brandsar, Jo. "Offshore Rankine Cycles." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19069.
Full textAbstract:
The title of the thesis - "Offshore Rankine Cycles" - is very general and cover a large range of engineering fields, e.g. thermodynamic cycles (Rankine, ORC, Brayton, Kalina, etc.), mechanical equipment (gas/steam turbine, heat exchangers and additional equipment) and safety concerns (flammable and/or toxic fluids, high temperature and pressures), to name the most important.The thesis try to give a brief overview of all critical points and alternatives, concerning employment of a waste heat recovery machine on offshore facilities, although focus has been on three more specified cases, namely:1. Comparison of a steam cycle vs. an organic Rankine cycle for high temperature operating conditions.2. Study of heat exchanger parameters on total cycle performance.3. Investigation of a modular expander setup versus a single expander.To compare a steam cycle to an organic cycle, a choice of working fluid for the organic cycle had to be made. After some investigation, toluene was chosen as it is a "common" fluid with known properties and was found to be a viable option for high temperature heat sources, both for subcritical and supercritical operation. Due to water being constricted to subcritical operation a CO2 cycle was implemented as a comparison to the supercritical toluene cycle. The main focus of the comparison was exergy losses during heat transfer and power output.The heat exchanger parameter study was conducted with a printed circuit heat exchanger as an example. The study of overall cycle performance has close connections to the heat exchanger size, since it is an important parameter concerning offshore employment due to costly "footprint". The cycle's dependency on the heat exchanger is mainly by the heat transfer rate, or heat load, which the heat exchanger applies to the cycle. The heat transfer rate is given by the heat exchanger`s ability to reduce the temperature of the exhaust gases. This ability depends on the two fluids involved and the geometry of the heat exchanger. While the choice in working fluid and pinch points sets the amount of heat transferred, the remaining analysis rest on the overall heat transfer coefficient (UA) to balance the heat load. When fluid properties are determined, the UA - value is again dependent on heat exchanger geometry and further variation of these parameters will in turn reveal the size of the heat exchanger. When imposing a working fluid to the cold side of the heat exchanger an optimization in heat exchanger volume could be found at specified heat load.A VBA macro has been made where expander parameters (rated power and efficiency vs. volumetric flow rate values) could be used as inputs to calculate the power output of two expanders in a modular setup relative to a single expander as reference.
9
Kaminanai, Srihder. "Finding Hamiltonian Cycles." TopSCHOLAR®, 2005. http://digitalcommons.wku.edu/theses/504.
Full textAbstract:
Finding a Hamiltonian cycle in a graph is used for solving major problems in areas such as graph theory, computer networks, and algorithm design. In this thesis various approaches of Hamiltonian cycle algorithms such as backtrack algorithms and heuristic algorithms, their basic ideas, and their actual implementations are studied. Three specific implementations are explained in detail and tested with randomly generated 4-regular planar graphs that are 2-connected and 4-edge connected. The results are analyzed and reported.
10
Verstraete, Jacques Baudouin Alain. "Cycles in graphs." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621434.
Full text
11
Darby, Heather. "Cycles of Nature." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2348.
Full textAbstract:
My work focuses on my physical connection to the earth. I translate what I see and visualize in nature into graphic shapes and patterns using textiles, fibers, and paints. Further, I interweave these materials through a variety of techniques, and I incorporate sewn lines to create compositions highlighting natural elements that depict the course of life. I employ a hands-on, low technology approach. This tactic contrasts my work as a professional graphic designer. While my professional efforts generally lack a physical connection with nature, due to digital simulations of real objects, my personal artwork allows me to step away from the insipid technology tools commonly used in today’s society.
12
Powell, Brian Edward. "The influence of minor cycles on low cycle fatigue crack growth." Thesis, University of Portsmouth, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354380.
Full textAbstract:
Fatigue crack propagation rates have been measured for two titaniumbased aeroengine disc alloys using compact tension test pieces. The loading block employed simulates two features of the engine flight pattern. A major stress cycle represents the start-stop operation which leads to low cycle fatigue. In-flight vibrations, which may give rise to high cycle fatigue, are represented by superimposed minor cycles of high frequency. This combined loading is applied in a specially developed test facility consisting of an electromagnetic vibrator mounted above a servohydrau1ic actuator. When the minor cycles are inactive the fractographic cracking processes are those associated with major cycle crack growth. Once active, the minor cycle growth may either generate extensive cyclic cleavage or increase the separation of the fatigue striations associated with the periodic major cycles. The contribution of the minor cycles to the total growth rate is dependent on their relative number and size. In gas turbine and compressor discs and blades, components which experience large numbers of minor cycles per flight, the damage associated with active minor cycles is dominant. Consequently, the onset of minor cycle damage effectively determines the useful life of such components. The threshold values associated with the minor cycles have been used to predict the onset of minor cycle activity. Similarly the method of linear superposition has been used to predict the subsequent fatigue crack growth rates. These predictions are successful for Ti-6Al-4V, whilst for Ti-5331S they are either found to be accurate or safe. Although Ti-5331S displays a marginally greater resistance to the onset of minor cycle crack growth, of greater significance is its reduced crack growth rates prior to this event. As a consequence components fabricated from Ti-5331S will exhibit longer fatigue crack propagation lives when subjected to the conjoint action of high and low cycle fatigue.
13
Campo, Woytuk Nadia. "Curious Cycles: Feminist Probes for Cultivating Curiosity of the Menstrual Cycle." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254985.
Full textAbstract:
Curious Cycles responds to the tensions that arise when designing technologies for menstruation and menstrual cycles, touching upon notions of curiosity, noticing, sharing, taking or making space, and our relationships with our bodies and their fluids. The project follows a Research through Design approach, guided by Soma Design and feminist research methods. Curious Cycles are a set of cultural probes; objects and interactions designed to gather experiences and insights from ve people who menstruate, throughout the duration of a cycle (approximately one month). The objects are meant to "cultivate curiosity", provoking reections on the ways we currently relate to our bodies and bodily uids and speculating on how we might relate to them in the future. This work seeks to approach the design method of cultural probes from a feminist perspective and contributes through the concept of "cultivating curiosity", a way to design menstrual cycle technologies by attending closely to the changing social and material experiences of the body, which in turn can challenge the cultural taboos surrounding menstruation.Curious Cycles svarar mot spänningarna som uppkommer när teknologier designas för menstruation och menstruationscykeln, genom idéer kring nykenhet, att märka, att dela med sig, att ta eller göra plats, och våra relationer med våra kroppar och deras vätskor. Projektet följer en Research through Design metodik, guidad av Soma Design och feministiska forskningsmetoder. Curious Cycles är en uppsättning cultural probes; föremål och interaktioner designade för att samla erfarenheter och insikter från fem menstruerande personer genom deras hela menstruationscykel (vilka pågår cirka en månad). Föremålen är menade att kultivera nykenhet för att framkalla reektioner kring de sätt vi för närvarande relaterar till våra kroppar och kroppsliga vätskor på, och även för att spekulera kring hur vi kan relatera till de i framtiden. Detta arbete närmar sig cultural probes från feministiska perspektiv och bidrar med konceptet "cultivating curiosity", ett sätt att designa teknologier för menstruationscykeln genom att ingående uppmärksamma förändringar av sociala och materiella erfarenheter av kroppen, vilket i sin tur kan utmana kulturella tabun kring menstruation.
14
Rafiq, M. S. "From shocks to cycles - an examination of Euro area economic cycles." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/8136.
Full textAbstract:
It is often the case that the key stumbling block for policy formation is limited knowledge of the way the macroeconomy works. Along with the introduction of a common currency, the interest and need for business cycle analysis at the Euro area level has increased. For this reason, at the present time business cycle researrh for the Euro area has an added significance, given current efforts to understand the workings of the Euro area economy, in terms of the impulse - real, monetary and international - and propagation mechanisms that drive the cycle, so as to design Euro-wide policies. The Euro area's internal mechanisms are explored by using various shock-basedm odels to investigate, first, how much of the Euro area business cycle is due to various shocks - be they real or nominal - and second, whether these shocks explain the dampening in the Euro, area business cycle over the last two decades. This so-called 'great moderation' - the decline in volatility for the Euro area is measured to be just over 40 percent during the past two decades - has only recently motivated economists to ask why business cycles over the past decade are now less volatile across the developed world than was the case in the 1970s and 1980s. These lines of enquiry are extended to investigate the role the Euro area economy plays in the wider global economy by examining the importance of international shocks on the Euro area economy. Linking in with the moderation literature, the study explores whether international shocks have been a key contributing factor behind the decline in business cycle volatility. Little, if any, work examining these issues for the Euro area have been yet undertaken. Allowing for caveats, the results show permanent productivity shocks - modelled using the balanced growth assumptions - to have had a significant role in driving output fluctuations for the Euro area, though they are not quite as important as claimed by real- business-cycle theory. The results also go on to show that permanent shocks explain a larger proportion of the decline in output volatility than is the case with monetary shocks. The estimation undertaken in chapters 4 and 5 show that despite the moderation in business cycle volatility being associated with structural change in the early 1990s, benign business cycles in the Euro area have been mom down to 'good luck' than good policies, such as changes in the priority of monetary policy. Finally, consistent with the good luck hypothesis, the results show output growth to have become more forecastable - as measured by the mean-squared-forecast-error - over the last two decades. Although, this improvement is constrained mainly to asset price variables, with little improvement in the forecasting power of monetary aggregates.
15
Amar, Denise. "Théorie des graphes, étude de cycles dans les graphes orientés et non orientés : plus long cycle, cycles de longueur donnée, hamiltonisme, pancyclisme." Bordeaux 1, 1985. http://www.theses.fr/1985BOR10617.
Full textAbstract:
Etude des cycles d'un graphe oriente ou non, satisfaisant des conditions sur divers parametres : stabilite, connexite, degre minimum, nombre d'aretes. Problemes concernant la longueur maximum d'un cycle, l'hamiltonisme, le pancyclisme, la couverture des sommets du graphe par des cycles de longueur fixee. Problemes algorithmiques
16
Jaeger, Robert. "Coloring the Square of Planar Graphs Without 4-Cycles or 5-Cycles." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3816.
Full textAbstract:
The famous Four Color Theorem states that any planar graph can be properly colored using at most four colors. However, if we want to properly color the square of a planar graph (or alternatively, color the graph using distinct colors on vertices at distance up to two from each other), we will always require at least \Delta + 1 colors, where \Delta is the maximum degree in the graph. For all \Delta, Wegner constructed planar graphs (even without 3-cycles) that require about \frac{3}{2} \Delta colors for such a coloring.
To prove a stronger upper bound, we consider only planar graphs that contain no 4-cycles and no 5-cycles (but which may contain 3-cycles). Zhu, Lu, Wang, and Chen showed that for a graph G in this class with \Delta \ge 9, we can color G^2 using no more than \Delta + 5 colors. In this thesis we improve this result, showing that for a planar graph G with maximum degree \Delta \ge 32 having no 4-cycles and no 5-cycles, at most \Delta + 3 colors are needed to properly color G^2. Our approach uses the discharging method, and the result extends to list-coloring and other related coloring concepts as well.
17
Winders, Christopher. "Cycles of cycles : ordering principles suggested by George Perle's twelve-tone tonality /." Digitized version, 2008. http://hdl.handle.net/1802/7600.
Full textAbstract:
Thesis (Ph. D.)--University of Rochester, 2008.Includes vita and abstract. Accompanies: Concerto grosso for string quartet and string orchestra / by Christopher Clay Winders. Includes bibliographical references. Digitized version available online via the Sibley Music Library, Eastman School of Music http://hdl.handle.net/1802/7600
18
Kernen, Joakim. "Trends, cycles and institutions : -Job polarization and the business cycle in Europe." Thesis, Uppsala universitet, Nationalekonomiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-367063.
Full textAbstract:
This thesis studies the cyclical aspect of job polarization in Europe. Contributions include offering a comparison to the findings of previous research on the United States, and extending the analysis by introducing labor market institutions. The analysis is done in two parts, first showing that the observed link between job polarization and jobless recoveries in the US is observed in Europe, but not across all countries and business cycles. In Scandinavia, the process of job polarization appears smoother than the spurts observed in the US. The second part involves regression analyses of the relationship between labor market institutions, the business cycle and occupational employment. The results indicate that stricter labor market institutions are less robustly associated with Routine employment than other occupational groups and that Routine employment is more sensitive to the business cycle than other types of employment. Further, rigid labor market institutions may prevent some of the Routine decline associated with economic downturns, while not necessarily affecting the long run employment. Limitations of the analysis regards rough estimates of the key variables, number of observations and the lack of identification associated with cross-country analyses.
19
Kühn, Daniela. "Cycles, minors and trees." [S.l.] : [s.n.], 2001. http://www.sub.uni-hamburg.de/disse/511/kuehn.pdf.
Full text
20
Karadimitropoulou, Aikaterini E. "Essays in macroeconomic cycles." Thesis, University of Kent, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580374.
Full textAbstract:
This thesis is structured around three main essays. The first focused on the sources of current account (CA) fluctuations in industrialized countries. Using a SVAR model with minimal long-run identifying restrictions, we identified external productivity shocks, domestic permanent and temporary output shocks, and demand or preferences shocks. We have found that the present value model (PVM) of the CA is consistent with the behaviour of the data for all countries except for France and the UK, where permanent domestic shocks have a long-run impact on the CA. Preferences shocks and, mostly, external supply shocks appear to play an important role in explaining CA fluctuations. Our model also reduces the degree of excess response of the CA to temporary output shocks found in previous literature. The second essay provides descriptive evidence at a disaggregate level on the behaviour of a large set of developed and emerging markets around recession dates. Using sectoral value added (VA), employment and productivity data, we unveiled a set of regularities for both sets of countries, while grouping industries according their level of productivity and external financial dependence. Also, we distinguished financial from normal recessions. Most importantly, results show that recessions tend to be more industry-specific events in emerging markets and economy-wide phenomena in developed countries. Moreover, the amplitude of the cycle for VA and productivity growth is larger -for emerging markets. Also industries with high dependence on external finance generally face higher contractions in V A, especially in the case of financial recessions. The third and final essay examined the importance of sector-specific factors in explaining business cycles (BC) co-movement, by analyzing international co- movements of VA growth in a multi-sector dynamic factor model. The model contains a World, country-specific, and sector-specific factors, and idiosyncratic components. We estimated the model using Bayesian methods for 30 sectors in the G7 economies for the 1974-2004 period. Our findings show that although there is a substantial role for sector-specific factors, fluctuations are dominated by country- factors. Also, the World factor appears to play a minimal role. Finally, our results suggest that, contrary to the convergence hypothesis, BC at a disaggregate level have not on average become more synchronized at the international level.
21
Liu, Kai. "Essays on business cycles." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708384.
Full text
22
Flandrin, Evelyne. "Cycles dans les graphes." Paris 11, 1990. http://www.theses.fr/1990PA112022.
Full textAbstract:
Cette these est composee de 3 chapitres: le premier chapitre contient d'abord une synthese des proprietes des graphes sans k#1#,#3 en particulier les proprietes concernant l'existence de cycles de longueur donnee dans de tels graphes et huit articles decrivant nos resultats. Certains de ces resultats generalisent des conditions d'existence de cycles hamiltoniens a des familles de graphes plus larges. Le second chapitre est forme de 2 articles. Dans le premier, nous demontrons la conjecture suivante formulee independamment par r. Haggkvist et par j. Mitchem et e. Schmeichel: si g est un graphe d'ordre n hamiltonien non biparti de degre minimum au moins (2n+1)/5, alors g est pancyclique. Dans le deuxieme nous deduisons quelques corollaires. Dans le 3eme chapitre, nous resolvons un probleme de numerotation gracieuse des chemins, repondant ainsi a une conjecture de i. Cahit
23
Browne, J. A. "Multiple expansion refrigeration cycles." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/23793.
Full text
24
Ghazo, Hanna Zeina. "Cycles combinatoires et géométriques." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0006.
Full textAbstract:
Le travail de cette thèse se situe dans les domaines de la théorie combinatoire des graphes, la combinatoire algébrique et la géométrie discrète. D'un part, il concerne l'énumération des chemins et cycles Hamiltoniens de type donné dans un tournoi ; de l'autre part, il étudie des suites numériques vérifiant une équation à différence quadratique. Parmi les résultats obtenus dans la première partie, on trouve : une égalité entre le nombre des chemins (resp. cycles) Hamiltoniens d’un type donné dans un tournoi et dans son complément; une expression du nombre de chemins Hamiltoniens d’un type donné pour un tournoi transitif en termes d'une fonction récursive F appelée « path-function »; la construction d'un algorithme pour le calcul de F. L'objet fondamental dans la deuxième partie est un graphe cyclique muni d'une solution d'une équation à différence quadratique. Un paramètre de cette équation distingue les solutions réelles et les solutions complexes. Une correspondance entre les solutions réelles et une classe de polynômes à coefficients entiers positifs est établie. Pour compléter la correspondance, les digraphes Eulériens à un pas interviennent. Une solution complexe détermine une marche fermée dans le plan pour laquelle à chaque pas on tourne à gauche ou à droite par un angle constant (l'angle tournant). Cette fois-ci les polynômes cyclotomiques jouent un rôle important. La caractérisation des polynômes qui déterminent de telles suites est un problème qu’on surmonte afin d'élucider des propriétés géométriques de tels cycles polygonaux. Notamment, lorsque la marche exploite les côtés d'un polygone régulier avec angle extérieur 2π/n, on trouve des phénomènes non anticipés lorsque n≥12The work in this thesis concerns the combinatorial theory of graphs, algebraic combinatorics and discrete geometry. On one side, it is about enumerating Hamiltonian paths and cycles of a given type in a tournament; On the other side, it studies numerical sequences verifying a quadratic difference equation.Concerning the results of the first part, we find: an equality between the number of Hamiltonians paths (resp. cycles) of a given type, in a tournament and its complement; an expression of the number of Hamiltonian oriented paths of a given type in a transitive tournament in terms of a recursive function F called the « path-function »; and the construction of an algorithm to compute F.In the second part of the work, we study cyclic graphs altogether with a solution to a quadratic difference equation.A parameter of this equation distinguishes real and complex sequences. A correspondence between real solutions and a class of polynomials with positive integer coefficients is established. To complete the correspondence, 1-step Eulerian digraphs interfere. A complex solution determines a closed planar walk in the plane, for which at each step we turn either left or right by a constant angle (the turning angle). This time, cyclotomic polynomials play a major role. Characterizing polynomials that determine such a solution is a problem that we study to the end of finding geometric properties of such polygonal cycles.When the walk exploits the sides of a regular polygon with exterior angle 2 π/n, we find unexpected phenomena when n≥ 12
25
Calhoun, Kathleen Cluverius. "Layers, Cycles and Stages." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2656.
Full textAbstract:
Deserted and disintegrating barns, houses, and silos have always perplexed me when driving through the country. I am fascinated by how this leisurely decay reveals their structural integrity in a slow, reverse process of construction. It is as if humanity and nature consciously collaborated to create these gigantic memento mori for a steady stream of highway viewers. These monumental tributes to inevitable decline, along with my own adventures in gardening, childrearing, eldercare, and travels, have led me to explore the universal cycles of life. The dilapidated buildings in my work are rendered in a tight, sharp, close-up viewpoint so that the viewer is forced to engage them. I will often layer images of seeds, leaves, and rocks on top of images of houses to symbolize the different stages of the life cycle. I see seeds and buildings as containers and incubators of potential. Any foliage represents a fulfillment of that potential, while rocks stand for the fossilized remains, or the achievements of one’s life accomplishments.
26
Zhang, Huiyan. "Essays on business cycles." Available to US Hopkins community, 2003. http://wwwlib.umi.com/dissertations/dlnow/3080804.
Full text
27
Bécard, Yvan. "Banks and business cycles." Thesis, Paris 1, 2018. http://www.theses.fr/2018PA01E009.
Full textAbstract:
La question centrale qui chapeaute cette thèse est : quelle sont les sources des fluctuations économiques ? De nombreux articles mettent en évidence le rôle majeur des facteurs et chocs financiers. A partir de ce postulat, j'analyse la capacité des modèles macroéconomiques dynamiques à reproduire les co-mouvements observés dans les données entre la production, la consommation, l'investissement et l'emploi, suite à un choc financier. Le premier chapitre montre que les modèles standards n'arrivent pas à générer ces co-mouvements, car ils impliquent des mouvements opposés entre la consommation et l'investissement. Une solution est de modéliser des banques qui prêtent à la fois aux entreprises et aux ménages, puis de considérer le choc financier comme un resserrement simultané des contraintes de crédit des deux types d'emprunteurs. Le second chapitre est une évaluation quantitative de cette idée. Avec David Gauthier, nous estimons un riche modèle macroéconomique sur données américaines à l'aide de méthodes bayésiennes. Nous motivons notre choc de collatéral par l'observation que les banques américaines ajustent les conditions de crédit de manière similaire pour les firmes et les ménages. Nous trouvons que le choc de collatéral explique une large partie des fluctuations économiques, car il est capable de générer les co-mouvements. Le troisième chapitre est l'étape suivante. Je souhaite endogénéiser les conditions de prêts bancaires. L'idée est de reproduire la récession de 2008, au cours de laquelle un choc dans le marché immobilier affectant initialement les ménages a été transmis au reste de l'économie à travers les banques qui ont diminué le crédit alloué aux entreprisesThe main question at the heart of this thesis is, what drives business cycle fluctuations? A growing body of evidence suggests that financial factors and shocks matter most. Based on this premise, I ask whether financial shocks in dynamic macroeconomic models can generate the positive co-movements in output, consumption, investment, and hours worked observed in the data. The first chapter shows that standard models fail in doing so, because they typically imply a countercyclical response of consumption. One solution is to have banks lend both to firms and households, and to assume, that the financial shock is a common credit tightening on both. The second chapter offers a quantitative analysis of this idea. Together with David Gauthier, we motivate what we call the collateral shock by documenting that banks in the US effectively adjust standards in a similar way regard less if the borrower is a firm or a household. We estimate a rich macroeconomic model with Bayesian methods on US financial and macro data over the 1985-2015 period. We find that the collateral shock is the main driver of economic fluctuations. The reason is the collateral shock is able to generate pro cyclical consumption, investment, hours, and credit to firms and households, which are features of US business cycles. The third chapter attempts to go a step further by making lending standards endogenous. The idea is to have banks act as a propagation channel. A shock that emerges in the housing market and that initially affects households is transmitted to firms by a panic-prone financial sector that tightens credit to businesses. This model would replicate the story of the 2008 recession in the United States
28
Kochersperger, Matthieu. "Cycles proches, cycles évanescents et théorie de Hodge pour les morphismes sans pente." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX041/document.
Full textAbstract:
Dans cette thèse nous nous intéressons aux singularités d'espaces analytiques complexes définis comme le lieu des zéros d'un morphisme sans pente. Nous étudions dans un premier temps les cycles proches et les cycles évanescents associés à un tel morphisme. Dans un deuxième temps nous cherchons à comprendre la théorie de Hodge des morphismes sans pente.La première partie de cette thèse est consacrée à apporter des compléments au travail de P. Maisonobe sur les morphismes sans pente. Nous commençons par construire un morphisme de comparaison entre cycles proches algébriques (pour les $mathscr{D}$-modules) et cycles proches topologiques (pour les faisceaux pervers). Nous montrons ensuite que ce morphisme est un isomorphisme dans le cas d'un morphisme sans pente. Enfin nous construisons un foncteur cycles évanescents topologiques pour un morphisme sans pente et nous démontrons que ce foncteur et le foncteur cycles proches topologiques de P. Maisonobe se placent dans le diagramme de triangles exacts attendu.Dans la seconde partie de cette thèse nous étudions les morphismes sans pente pour les modules de Hodge mixtes. Nous démontrons dans un premier temps la commutativité des cycles proches et des cycles évanescents itérés appliqués à un module de Hodge mixte dans le cas d'un morphisme sans pente. Dans un deuxième temps nous définissons la notion << strictement sans pente >> pour un module de Hodge mixte et nous démontrons sa stabilité par image directe propre. Nous démontrons comme application la compatibilité de la filtration de Hodge et des filtrations de Kashiwara-Malgrange pour certains modules de Hodge purs supportés sur une hypersurface à singularités quasi-ordinairesIn this thesis we are interested in singularities of complex varieties defined as the zero locus of a morphism without slope. In a first time we study nearby cycles and vanishing cycles associated to such morphisms. In a second time we want to understand Hodge theory of morphisms without slope.The first part of this thesis is devoted to add some complements to the work of P. Maisonobe on morphisms without slope. We start with the construction of a comparison morphism between algebraic nearby cycles (for $mathscr{D}$-modules) and topological nearby cycles (for perverse sheaves). Then we show that this morphism is an isomorphism in the case of a morphism without slope. Finally we construct a topological vanishing cycles functor for a morphism without slope et we prove that this functor and the topological nearby cycles functor of P. Maisonobe fit into the expected diagram of exact triangles.In the second part of the thesis we study morphisms without slope for mixed Hodge modules. We first show the commutativity of iterated nearby cycles and vanishing cycles applied to a mixed Hodge module in the case of a morphism without slope. Second we define the notion "strictly without slope" for a mixed Hodge module and we show that it is preserved by proper direct image. As an application we prove the compatibility of the Hodge filtration and Kashiwara-Malgrange filtrations for some pure Hodge modules with support an hypersurface with quasi-ordinary singularities
29
Yang, Chen. "Thermodynamic Cycles using Carbon Dioxide as Working Fluid : CO2 transcritical power cycle study." Doctoral thesis, KTH, Tillämpad termodynamik och kylteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-50261.
Full textAbstract:
The interest in utilizing the energy in low‐grade heat sources and waste heat is increasing. There is an abundance of such heat sources, but their utilization today is insufficient, mainly due to the limitations of the conventional power cycles in such applications, such as low efficiency, bulky size or moisture at the expansion outlet (e.g. problems for turbine blades). Carbon dioxide (CO2) has been widely investigated for use as a working fluid in refrigeration cycles, because it has no ozonedepleting potential (ODP) and low global warming potential (GWP). It is also inexpensive, non‐explosive, non‐flammable and abundant in nature. At the same time, CO2 has advantages in use as a working fluid in low‐grade heat resource recovery and energy conversion from waste heat, mainly because it can create a better matching to the heat source temperature profile in the supercritical region to reduce the irreversibility during the heating process. Nevertheless, the research in such applications is very limited. This study investigates the potential of using carbon dioxide as a working fluid in power cycles for low‐grade heat source/waste heat recovery. At the beginning of this study, basic CO2 power cycles, namely carbon dioxide transcritical power cycle, carbon dioxide Brayton cycle and carbon dioxide cooling and power combined cycle were simulated and studied to see their potential in different applications (e.g. low‐grade heat source applications, automobile applications and heat and power cogeneration applications). For the applications in automobile industries, low pressure drop on the engine’s exhaust gas side is crucial to not reducing the engine’s performance. Therefore, a heat exchanger with low‐pressure drop on the secondary side (i.e. the gas side) was also designed, simulated and tested with water and engine exhaust gases at the early stage of the study (Appendix 2). The study subsequently focused mainly on carbon dioxide transcritical power cycle, which has a wide range of applications. The performance of the carbon dioxide transcritical power cycle has been simulated and compared with the other most commonly employed power cycles in lowgrade heat source utilizations, i.e. the Organic Rankin Cycle (ORC). Furthermore, the annual performance of the carbon dioxide transcritical power cycle in utilizing the low‐grade heat source (i.e. solar) has also been simulated and analyzed with dynamic simulation in this work. Last but not least, the matching of the temperature profiles in the heat exchangers for CO2 and its influence on the cycle performance have also been discussed. Second law thermodynamic analyses of the carbon dioxide transcritical power systems have been completed. The simulation models have been mainly developed in the software known as Engineering Equation Solver (EES)1 for both cycle analyses and computer‐aided heat exchanger designs. The model has also been connected to TRNSYS for dynamic system annual performance simulations. In addition, Refprop 7.02 is used for calculating the working fluid properties, and the CFD tool (COMSOL) 3 has been employed to investigate the particular phenomena influencing the heat exchanger performance.QC 20111205
30
Male, Rachel Louise. "Developing country business cycles : characterizing the cycle and investigating the output persistence problem." Thesis, University of York, 2009. http://etheses.whiterose.ac.uk/864/.
Full textAbstract:
Identifying business cycle stylised facts is essential as these often form the basis for the construction and validation of theoretical business cycle models. Furthermore, understanding the cyclical patterns in economic activity, and their causes, is important to the decisions of both policymakers and market participants. This is of particular concern in developing countries where, in the absence of full risk sharing mechanisms, the economic and social costs of swings in the business cycle are very high. Previous analyses of developing country stylised facts have tended to feature only small samples, for example the seminal paper by Agénor et al. (2000) considers just twelve middle-income economies. Consequently, the results are subjective and dependent on the chosen countries. Motivated by the importance of these business cycle statistics and the lack of consistency amongst existing research, this thesis makes an important contribution to the literature by extending and generalising the developing country stylised facts; examining both classical and growth cycles for a sample of thirty-two developing countries. One significant finding that emerges is the persistence of output fluctuations in developing countries and the strong positive relationship between the magnitude of this persistence and the level of economic development. The observation of procyclical real wages and significant price persistence indicates the suitability of a New Keynesian dynamic general equilibrium model with sticky prices, to explore this relationship; thus, the vertical production chain model of Huang and Liu (2001) was implemented. This model lends itself to such an analysis, as by altering the number of production stages (N) it is possible to represent economies at different levels of development. There was found to be a strong significant positive relationship between the magnitude of output persistence generated by the model and economic development. However, a very significant finding of this analysis is that the model overestimates output persistence in high inflation countries and underestimates output persistence in low inflation countries. This has important implications not only for this model, but also for any economist attempting to construct a business cycle model capable of replicating the observed patterns of output persistence.
31
Bazhov, Ivan. "Zero-cycles and constant cycle subvarieties in Calabi-Yau and hyper-Kähler varieties." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066387/document.
Full textAbstract:
Nous présentons trois résultats dans cette thèse. Dans le chapitre 2 nous montrons l’existence d’un zéro-cycle cx sur une hypersurface X de type Calabi–Yau dans une varieté homogène projective complexe. Plus précisement, nous montrons que l’intersection de n diviseurs sur X, où n = dim X, est proportionnelle à la classe d’un point supporté sur une courbe rationnelle dans X. Dans le chapitre 3 nous donnons une nouvelle preuve du théorème de Beauville et Voisin portant sur la décomposition de la petite diagonale d’une surface K3 notée S. La preuve que nous donnons est explicite et utilise le plongement de degré 2g-2 de S dans l’espace projectif de la dimension g. Elle est différente de celle donnée par Beauville et Voisin, qui repose sur l’existence d’une famille à un paramètre de courbes elliptiques. Le chapitre 4 est consacré à l’étude des similitudes entre la variété de Fano des droites d’une cubique de dimension 4, qui est une variété hyper-Kählerienne étudiée par Beauville et Donagi, et la variété hyper-Kählerienne de dimension 4 construite par Debarre et Voisin dans [11]. Nous introduisons un analogue de la notion de triangle pour ces variétés et prouvons que la variété des triangles, qui est de dimension 6, est une sous-variété Lagrangienne du cube de la variété hyper-Kählerienne construite par Debarre et VoisinWe present in this thesis three results. In Chapter 2 we prove the existence of a canonical zero-cycle cX on a Calabi–Yau hypersurfacee X in a complex projective homogeneous variety. Namely, we show that the intersection of any n divisors on X , n = dim X is proportional to the class of a point on a rational curve in X. In Chapter 3 we give a new proof of the theorem of Beauville and Voisin about the decomposition of the small diagonal of a K3 surface S. Our proof is explicit and uses the degree 2g-2 embedding of S in projective space of dimension g. It is different from the one used by Beauville and Voisin, which employed the existence of one-parameters familie of elliptic curves. Chapter 4 is devoted to the study of similarities between the Fano varieties of lines on a cubic fourfold, a hyper-Kähler fourfold studied by Beauville and Donagi, and the hyper-Kähler fourfold constructed by Debarre and Voisin in [11]. We exhibit an analog of the notion of "triangle" for these varieties and prove that the 6-dimensional variety of "triangles" is a Lagrangian subvariety in the cube of the constructed hyper-Kähler fourfold
32
Gatfaoui, Jamel. "Modeling Chinese provincial business cycles." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM1110.
Full textAbstract:
Cette thèse étudie les cycles économiques provinciaux chinois durant la période 1989-2009. Dans un premier temps, Nous utilisons une variété de techniques afin d'examiner la nature et le degré de comouvement entre les cycles de croissance provinciaux chinois. Nous détectons différentes propriétés des cycles de croissance provinciaux. En utilisant une méthodologie de classification basée sur un modèle, nous constatons que les provinces peuvent être classées parmi cinq classes en fonction des mesures standards des caractéristiques cycliques. Bien que la majorité des provinces a connu la récession qui a eu lieu autour de la crise asiatique, la nation dans son ensemble a connu une phase d'expansion. En outre, toutes les provinces, ont connu la récession liée à la crise financière internationale qui a eu lieu en 2007/2008 à l'exception du Jiangsu et Tianjin. Toutes les provinces côtières, sauf Hainan, sont significativement synchronisées avec le cycle national. En outre, nous constatons que les quatre principales récessions nationales sont bien diffusées dans tout le pays. Ensuite, nous analysons la co-cyclicité entre les provinces dans chacune des six régions définies par Groenewold et al. (2008). Nous nous basons sur la décomposition tendance-cycle en utilisant le modèle à composantes inobservables univarié et multivarié. Nous trouvons que La majorité des cycles provinciaux reflètent des chocs de la demande plutôt que des chocs de l'offre. En examinant si des cycles communs existent au sein de chaque région, nous pouvons formuler des conclusions sur la pertinence de la définition de ces régionsThis thesis deals with the Chinese provincial growth cycles over the period 1989-2009. First, we use a variety of techniques to examine the nature and degree of comovement among Chinese provincial growth cycles. We detect different properties of the provincial growth cycles. Using a model-based clustering methodology, we find that provinces can be classified among five major clusters as a function of standard measures of cyclical characteristics. Although the majority of provinces experienced the recession that occurred around the Asian crisis, the nation as whole experienced an expansionary phase. Moreover, all the provinces experienced the recession related to the subprime crisis that occurred in 2007/2008 except Jiangsu and Tianjing. However, All coastal provinces except Hainan are significantly synchronized with the national cycle. Furthermore, we find that the main four national recessions are well diffused across the country. Then, we analyse the co-cyclicality between provinces in each of the six regions defined by Groenewold et al. (2008). We rely on trend-cycle decomposition by using both univariate and multivariate unobserved component model. The majority of provincial cycles reflect demand rather than supply-side shocks. By examining the commonality of provincial growth cycles within each region, we ask whether the definition of these regions is supported by statistical analysis. We find mixed results. Finally, we use a Markov switching model that allow for the identification of business/seasonal cycle interaction
33
Laimene, Karim. "Analyse des cycles de liquéfaction du gaz naturel. Analysis of natural gas liquefaction cycles." Université catholique de Louvain, 2003. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-04012003-164249/.
Full textAbstract:
Le développement et l'utilisation des procédés industriels à basse température ont été très importants durant ces dernières années. Le développement est surtout dû à l'accroissement de la demande en produits liquides (purs ou mélanges) sur le marché mondial. L'auteur de cette thèse propose une analyse approfondie des trois grandes familles de procédés de liquéfaction du gaz naturel utilisés en Algérie. Il commence par examiner les traitements subis par le gaz naturel avant sa liquéfaction qui consiste à le ramener à une température de -160°C et à une pression légèrement supérieure à la pression atmosphérique. Il analyse ensuite, à l'aide du logiciel ASPEN PLUS, les différentes performances des trois types de cycles et conclut en montrant que le cycle Propane-MCR est thermodynamiquement le plus avantageux.
34
van, Rij Inge. "The 'Liedersträuße' of Johannes Brahms : song cycles, lyric cycles, multi-pieces or random collections?" Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/251822.
Full text
35
Huang, Lloyd Michael. "Analysis of multi-recycle thorium fuel cycles in comparison with once-through fuel cycles." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47662.
Full textAbstract:
The purpose of this research is to develop a methodology for a thorium fuel recycling analysis that provides results for isotopics and radio-toxicity evaluation and analysis. This research is motivated by the need to reduce the long term radiological hazard in spent nuclear fuel, which mitigates the mixing hazard (radiotoxicity and chemical toxicity) and decay heat load on the repository. The first part of the thesis presents comparison of several once-through cases with uranium and thorium fuels to show how transuranics build up as fuel is depleted. The once-through analysis is performed for the following pairs of comparison cases: low enriched uranium dioxide (UOX) vs. thorium dioxide with 233UOX (233U-ThOX), natural uranium dioxide mixed with transuranic oxides (U-TRUOX) vs. thorium dioxide mixed with transuranic oxides (Th-TRUOX), natural uranium dioxide mixed with weapons grade plutonium dioxide (U-WGPuOX) vs. thorium dioxide mixed with weapons grade plutonium dioxide (Th-WGPuOX), natural uranium dioxide mixed with reactor grade plutonium dioxide (U-RGPuOX) vs. thorium mixed with reactor grade plutonium dioxide (Th-RGPuOX). The second part of the research evaluates the thorium fuel equilibrium cycle in a pressurized water reactor (PWR) and compares several recycling cases with different partitioning schemes. Radio-toxicity results of the once-through cycle and multi-recycle calculations demonstrate advantages for thorium fuel and reprocessing with respect to long term nuclear waste management.
36
Hussein, Siti Almafahaza. "Business and Real Estate Cycles The Kuala Lumpur Office Market." Thesis, KTH, Bygg- och fastighetsekonomi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-77472.
Full textAbstract:
Purpose - The purpose of this paper is to apply the concept of business cycle and real estate cycle in term of their characteristics, period and sequence of the cycle to the Kuala Lumpur’s office market. Design/methodology/approach - The paper is based on previous literature review, facts, reports, and data in arriving at the conclusion of the study. Findings - This paper revealed the characteristics, period and sequence between business and real estate cycles to Kuala Lumpur’s office market. Research limitation/ Implications - The framework and flows of this paper act as an introduction for the paper. Lacks of literature and attention on the business and real estate cycles in Kuala Lumpur’s have created difficulties to gains information and data on this paper. Practical implications - This paper is important for the students, government and policy maker in order to further a research and develop a foundation for business and real estate cycles in Kuala Lumpur.
37
Bartlett, Michael. "Developing Humidified Gas Turbine Cycles." Doctoral thesis, KTH, Chemical Engineering and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3437.
Full textAbstract:
As a result of their unique heat recovery properties,Humidified Gas Turbine (HGT) cycles have the potential todeliver resource-effective energy to society. The EvaporativeGas Turbine (EvGT) Consortium in Sweden has been studying thesetypes of cycles for nearly a decade, but now stands at acrossroads, with commercial demonstration remaining. Thisthesis binds together several key elements for the developmentof humidified gas turbines: water recovery and air and waterquality in the cycle, cycle selection for near-term, mid-sizedpower generation, and identifying a feasible niche market fordemonstration and market penetration. Moreover, possiblesocio-technical hinders for humidified gas turbine developmentare examined.
Through modelling saltcontaminant flows in the cycle andverifying the results in the pilot plant, it was found thathumidification tower operation need not endanger the hot gaspath. Moreover, sufficient condensate can be condensed to meetfeed water demands. Air filters were found to be essential tolower the base level of contaminant in the cycle. This protectsboth the air and water stream components. By capturing airparticles of a similar size to the air filters, the humidifieractually lowers air stream salt levels. Measures to minimisedroplet entrainment were successful (50 mg droplets/kg air) andmodels predict a 1% blow down from the water circuit issufficient. The condensate is very clean, with less than 1 mg/lalkali salts and easily deionised.
Based on a core engine parameter analysis for three HGTcycle configurations and a subsequent economic study, asteam-cooled steam injected cycle complemented with part-flowhumidification is recommended for the mid-size power market.This cycle was found to be particularly efficient at highpressures and turbine inlet temperatures, conditions eased bysteam cooling and even intercooling. The recommended HGT cyclegives specific investment costs 30- 35% lower than the combinedcycles and cost of electricity levels were 10-18% lower.Full-flow intercooled EvGT cycles give high performances, butseem to be penalised by the recuperator costs, while stillbeing cheaper than the CC. District heating is suggested as asuitable niche market to commercially demonstrate the HGTcycle. Here, the advantages of HGT are especially pronounceddue their very high total efficiencies. Feasibility prices forelectricity were up to 35% lower than competing combinedcycles. HGT cycles were also found to effectively include wasteheat sources.
Keywords:gas turbines, evaporative gas turbines,humidification, power generation, combined heat and powergeneration.
38
Dalili, Farnosh. "Humidification in Evaporative Power Cycles." Doctoral thesis, KTH, Chemical Engineering and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3469.
Full textAbstract:
Evaporative gas turbine cycles (EvGT) show an exceptionalexhaust heat recovery potential, which makes them a strongcompetitor to other advanced gas turbine cycles, especiallyfrom small to intermediate sizes. Evaporative gas turbines aredistinguished by humidifying the working fluid beforecombustion at temperatures below the boiling point of water;and the heat required for evaporation of water is partly takenout of the exhaust gas. Thus, humidification is a key operationin these cycles. This thesis investigates, both theoreticallyand experimentally, two alternative approaches tohumidification: the packed-bed humidification tower and thetubular humidifier. Both these equipments involvecountercurrent contact between water and the working fluid.Humidifier design criteria are developed and criticalparameters such as flooding, wetting rate and entrainment arediscussed. The experimental parts were carried out on thepacked-bed tower in the EvGT pilot plant, and on a tubularhumidifier test rig especially erected for this purpose. Thetheoretical models were confirmed by the experiments.
The height of a transfer unit, necessary for designingpacked beds, was calculated for the packing employed in theEvGT pilot plant. It was found that the data provided by themanufacturer may be used with minor corrections.
The tubular test rig operated satisfactorily delivering hothumid air. The theoretical models coincided well with theexperimental results, verifying the design criteria developedhere. The heat transfer calculations indicated that mostresistance to heat transfer is on the exhaust gas side. Thus, asurface extended tube (Sunrod) was used in the test rig. Itcould be concluded that the tubular humidifier is a strongalternative to the packed-bedtower, especially in smallhigh-pressure gas turbines.
Furthermore, the importance of the non-ideality of theair-water vapor mixture in modeling evaporative cycles wasfirst highlighted in this work. Through applying realthermodynamic properties of air-water vapor mixtures in cyclecalculations, it was found that the compressed air contains ahigher amount of moisture than indicated by the ideal gasmixture model. This affects the design of the heat recoverysystem and cannot be neglected.
Key words:evaporative gas turbine, indirect-fired gasturbine, humidification, packed bed, tubular humidifier,evaporator, saturator.
39
Erdem, Fatma Pinar. "Business Cycles In Emerging Economies." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613853/index.pdf.
Full textAbstract:
Until very recently, most emerging market economies have achieved higher growth rates for the last decade. It is controversial whether this good economic environment
is due to domestic reforms or due to favorable external factors. In this framework, the main aim of this study is to investigate the structure and sources of business cycles in emerging market economies and to determine how these cycles differ than
those in developed countries. The role of external and domestic factors on business cycles are analyzed by applying not only the conventional panel data estimations but also common correlated effects panel mean group method which is introduced by Peseran (2006). Besides, the convergence of business cycles in emerging market economies to the business cycles in developed countries is discussed based on factor analysis. The major results indicate the common global factors are the leading source of the business cycles both in emerging market economies and developed countries. However, domestic determinants of fluctuations differ across two groups of countries. In addition, results show that in the last two decades fluctuations in emerging market economies have started to be more dependent on the fluctuations in developed countries.
40
Linaa, Jesper Gregers. "Business cycles and monetary policy /." Copenhagen, 2005. http://www.gbv.de/dms/zbw/501512020.pdf.
Full text
41
Solomon, Benjamin M. "Who Cycles Into Our Valley." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/english_theses/130.
Full textAbstract:
The twelve stories in this collection chart a course between the United States and India. Some are set wholly in one country, while others form a bridge between the two. Uniting them is a shared attention to memory, isolation, and loss. In their own idiosyncratic ways, each of the characters in these small fictions is struggling for human connection in a hostile and lonely world.
42
Jacob, David. "Analytical analysis of absorption cycles." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16094.
Full text
43
Pradhan, Pradnya Avinash. "Political monetary cycles in Mexico." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/28929.
Full text
44
Mackevičius, Ramūnas. "Logistical analysis of economic cycles." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121107_091040-28467.
Full textAbstract:
Dissertation deals with logistical analysis of economic cycles. Aim of the research - to reveal and to determine causes of cyclical economic fluctuations, according to economic logistic theory. Theoretical, logistical and empirical analyses of cyclical economic fluctuations are carried out in the work. Conception of economic cycle is specified. Evaluating provisions of economic logistic theory, two models are created – theoretical logistic economic cycle model and logistic economic system‘s cyclical fluctuation and development research model. In the dissertation the deep causes of economic cycles influencing their formation are revealed. The influence of innovative processes to the market formation, the impact of market capacity limitation to the market heating, saturation, hidden overproduction and to the formation of bubble process are determined. The influence of all the mentioned processes as well as economic paradoxes ((growing profitability paradox and credit trap paradox)) to the formation and working of economic cycle are revealed.Disertacija skirta logistinei ekonominių ciklų analizei. Darbo tikslas - vadovaujantis ekonomine logistine teorija atskleisti ir nustatyti ciklinio ekonominio svyravimo priežastis. Darbe atliekama teorinė, logistinė ir empirinė ciklinių ekonominių svyravimų analizė. Įvertinant ekonominės logistinės teorijos nuostatas, patikslinama ekonominio ciklo samprata, parengiamas teorinis logistinis ekonominio ciklo modelis ir logistinis ciklinio ekonominės sistemos svyravimo ir raidos tyrimo modelis. Darbe atskleidžiamos vidutinės trukmės ekonominių ciklų susiformavimą veikiančios giluminės priežastys. Nustatoma inovacinių procesų įtaka rinkos susiformavimui, rinkos talpos uždarumo įtaka rinkos kaitimui, rinkos prisotinimui ir paslėptosios perprodukcijos bei burbulo proceso susiformavimui. Taip pat atskleidžiama visų minėtų procesų ir ekonominių paradoksų (didėjančio pelningumo paradokso ir skolos spąstų paradokso) įtaka ekonominio ciklo formavimuisi ir veikimui.
45
Hardy, Nadia. "Odd cycles in planar graphs." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84037.
Full textAbstract:
Given a graph G = (V, E), an odd cycle cover is a subset of the vertices whose removal makes the graph bipartite, that is, it meets all odd cycles in G. A packing in G is a collection of vertex disjoint odd cycles. This thesis addresses algorithmic and structural problems concerning odd cycle covers and packings. In particular, we consider the two NP-hard problems of finding a maximum packing and a minimum covering. In 1994 Brass [53] conjectured that tau, the minimum size of an odd cycle cover, is at most twice nu, the maximum size of a packing. The conjecture is known to be false in general [11, 41]. We prove here that tau < 10nu for planar graphs. Our structural results leads to the first constant approximation algorithm for the packing problem. The covering problem was shown to be tractable for graphs of constant sized solutions [42]. We give a linear time algorithm for the covering problem restricted to the case where the graphs have constant sized solutions and are planar.
46
Denley, Tristan Mark Joseph. "Cycles, trees and Ramsey numbers." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283960.
Full text
47
Mainolfi, Nello. "Making cycles, bicycles and macrocycles." Thesis, King's College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415446.
Full text
48
Toyoda, Hiroki. "Asset Prices and Business Cycles." Kyoto University, 2019. http://hdl.handle.net/2433/236600.
Full text
49
Kelly, Luke Tristian. "On cycles in directed graphs." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/940/.
Full textAbstract:
The main results of this thesis are the following. We show that for each alpha > 0 every sufficiently large oriented graph G with minimum indegree and minimum outdegree at least 3 |G| / 8 + alpha |G| contains a Hamilton cycle. This gives an approximate solution to a problem of Thomassen. Furthermore, answering completely a conjecture of Haggkvist and Thomason, we show that we get every possible orientation of a Hamilton cycle. We also deal extensively with short cycles, showing that for each l > 4 every sufficiently large oriented graph G with minimum indegree and minimum outdegree at least |G| / 3 + 1 contains an l-cycle. This is best possible for all those l > 3 which are not divisible by 3. Surprisingly, for some other values of l, an l-cycle is forced by a much weaker minimum degree condition. We propose and discuss a conjecture regarding the precise minimum degree which forces an l-cycle (with l > 3 divisible by 3) in an oriented graph. We also give an application of our results to pancyclicity.
50
Soames, Kieron, and Jonas Lind. "Detecting Cycles in GraphQL Schemas." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-156174.
Full textAbstract:
GraphQL is a database handling API created by Facebook, that provides an effective al-ternative to REST-style architectures. GraphQL provides the ability for a client to spec-ify exactly what data it wishes to receive. A problem with GraphQL is that the freedomof creating customized requests allows data to be included several times in the response,growing the response’s size exponentially. The thesis contributes to the field of GraphQLanalysis by studying the prevalence of simple cycles in GraphQL schemas. We have im-plemented a locally-run tool and webtool using Tarjan’s and Johnson’s algorithms, thatparses the schemas, creates a directed graph and enumerates all simple cycles in the graph.A collection of schemas was analysed with the tool to collect empirical data. It was foundthat 39.73 % of the total 2094 schemas contained at least one simple cycle, with the averagenumber of cycles per schema being 4. The runtime was found to be on average 11 mil-liseconds, most of which consisted of the time for parsing the schemas. It was found that44 out of the considered schemas could not be enumerated due to containing a staggeringamount of simple cycles. It can be concluded that it is possible to test schemas for cyclicityand enumerate all simple cycles in a given schema efficiently.