Dissertations / Theses on the topic 'Property stocks'

The purpose of this dissertation is to determine whether size and book value to market value (BV/MV) effects dominate the property effects in the return generating process for Listed Property Trusts (LPTs) in Australia.The study endeavours to answer a critical question regarding listed property investment vehicles. That is, are they stocks or property? The approach, however, differs from previous studies in that it avoids utilising direct property data because of the inherent valuation-smoothing problems.Instead, it develops unique specialised indices for LPTs by size and BV/MV ratios. The analyses are conducted in four different ways. Amongst other findings, it is suggested that the two well known stock market effects, namely size and BV/MV effects, are significant in LPT returns. As such, by way of inference, it is suggested that property effects in LPT returns are subsumed under the effects of these two factors. The findings support the hybrid-asset hypothesis for LPTs; that is, LPTs are an asset class of its own, sharing to an extent, the characteristics of both shares and property direct.
Doctor of Philosophy (PhD)

South Africa has made a recent transformation from Property Loan Stock companies and Property Unit Trusts to the internationally recognised Real Estate Investment Trust structures. The locally listed companies that decided to adopt this structure should experience increased global interaction. This study focused primarily on the international direct or indirect real estate investments made from a South African Real Estate Investment Trust perspective. When conducting this investment, the respective companies must obtain financing for the investments, which will have an impact on capital and shareholder structure. The capital structure acts as an umbrella term that includes the shareholder’s equity and debt of a company. The study mainly focused on long-term debt. The shareholder structure focuses on the equity of South African Real Estate Investment Trusts in depth and determines if international activity had taken place. Global investments usually have a structure through which money is transferred to foreign countries to execute an investment. This is predominantly referred to as the company structure. The top 13 Real Estate Investment Trusts, by market capitalisation, were examined to first determine whether international investment took place and secondly whether their company structure experienced change after foreign property investments had been made. Emphasis was placed on the risks involved during the international investment process, the reason for company structure changes, as well as the benefits associated with these decisions. The various direct and indirect impacts that the previous themes have on the bottom line of a specific South African Real Estate Investment Trust were also explored, should these investors choose to capitalise on a global scale.
Dissertation (MSc (Real Estate))--University of Pretoria, 2017.
Construction Economics
MSc (Real Estate)
Unrestricted

Doutoramento em Economia
A investigação desenvolvida nesta dissertação centra-se no binómio Direitos de Propriedade / Política de Pescas. A transição de um regime de livre acesso para políticas de limitação à entrada e atribuição de quotas (mais ou menos transferíveis) significou uma alteração sensível na forma de entender os problemas das pescarias e de as ordenar de forma eficiente.A criação do regime das 200 milhas, ao atribuir aos países costeiros, direitos de propriedade e novas prerrogativas na gestão dos seus recursos, representou um imenso potencial para uma gestão sustentável das pescas, uma "Promessa de Abundância". A prática demonstrou que, sem uma política de redução da sobrecapacidade, e em presença de restrições de ordem social e política , estas conclusões devem ser relativizadas. Por outro lado, os problemas derivados da imprecisa definição de direitos nas zonas de Alto-Mar adjacentes às ZEEs, na Lei do Mar ( 1982), nomeadamente os relativos aos straddling stocks, implicam uma revisitação da "Tragédia dos Comums" e da relação entre regras de acesso e sobrepesca. Isto podemos comprovar pela análise do caso: A pesca do bacalhau na Terra Nova. Simultaniamente, avaliamos os efeitos da criação do regime das 200 milhas sobre a frota de pesca longínqua portuguesa que, tradicionalmente, pratica aquela pescaria.
In this dissertation we investigate Rights Based Management. The transition from free access to regulated fisheries with tools like limited entry and quotas (of different degrees of transferability) meant an important evolution in the way of understanding fisheries problems and managing them efficiently. Extended Fisheries Jurisdiction gave the coastal states property-rigths and the potential of a sustainable management of their fisheries resources. For many fisheries economists it was a "promise of abundance". In practice, without a policy of overcapacity reduction, and in the presence of multiple social and political constraints, these conclusions were reversed. Also, the problems of "unfinished business" in the Law of the Sea ( 1 982), namely the imprecise definition of rights in the areas of High-Seas adjacent to the EEZs and the consequent difficulties in the management of straddling stocks, makes it necessary to revisit the "Tragedy of the Commons" and the oldest issue: free access/ excess of effort/ overfishing. We could corraborate this by the analysis of cod fisheries in Newfoundland/Canada. We also avaliate the consequences of Extended Fisheries Jurisdiction and European Community integration on the Portuguese long-distance cod fisheries.

Thesis (MBA)--Stellenbosch University, 2005.
ENGLISH ABSTRACT: This study explores the feasibility of establishing a diversified hotel property fund (DHPF) on the Johannesburg Stock Exchange. To be launched in 2005/2006, the proposed unit trust fund is made up of a diversified portfolio of hotels located throughout South Africa. Research suggests that Hotel Property Funds have traditionally been the most volatile of Real Estate Investment Trusts (REITs) with their share value largely dependent on hotel revenue. However, investing in HPFs and REITs have numerous advantages such as their stipulated 90% dividend-payout ratio, steady stream of cash flow and zero corporate income taxes. The Property Unit Trust sector in South Africa in 2003 realised annualised rates of returns of 39%, and furthermore, the economic outlook and hotel industry sector show promising signs with economic growth rates for 2004 and 2005 reaching 4% and 5% respectively. This study thus considers whether a hotel property fund will succeed in South Africa and what returns investors can expect. By drawing on empirical and primary research and lessons learnt from international best practices this ground-breaking report identifies and analyses key performance variables of HPFs and REITs and applies them to a South African context. These variables include; capital structure, investment strategy, risk and return, Net Asset Value (NA V) and initial public offerings (IPO's). The report establishes that there is no optimal capital structure for REITs and only when the market reacts to the issuance of debt can one tell if the REIT is favourably structured or not. Concerning investment strategy, investors are in general, often lured to a diversified portfolio, however this report suggests that there is no optimal strategy for investing in REITs. In addition, over a medium to long term, REIT performance is strong, while over the short term performance is varied impacting on investor strategy. In assessing risk and return it was concluded that including REIT shares in an already diversified portfolio, the maximum expected return for each given level of risk is increased, and the level of risk for each level of expected return is reduced. Furthennore, the performance of RElTs is not necessarily detennined by size or Net Asset Value and thus small and large REITs can offer investors similar returns. Finally, initial-day returns for industry lnitial Public Offerings (lPO's) easily outperfonn REIT lPO's. Similarly to RElTs, there are numerous advantages to Hotel REITs which include, unlocking and redeployment of capital, investment spread and risk reduction and the provision of synergies between counter cyclical performing properties. However, empirical research indicates that Hotel REITs prove to be the most volatile of REIT sectors. Hotel REITs differ enonnously from their parent group in terms of their revenue & earnings which are more diverse in source and are generated from short-tenn leases. As such. Hotel REITs are also considered to be more management intensive. As with REITs there is no evidence to suggest an optimal capital structure and with the envisaged 50% debt ratio, the DHPF could be considered to be following international best practices. Several drawbacks with Hotel REITs include the lowest dividend yield among all RElT sectors, high volatility in income earnings, sensitivity to upswings and downturns in the tourism market, large capital investments and fixed operating expenses for staff and infrastructure. However despite these obstacles and in answer to the research problem, the prospects of the DHPF succeeding in South Africa are very high indeed. The REIT and Hotel REIT markets have proved successful throughout major capital markets, providing investors with a multitude of benefits. South Africa's economic and tourism climate is very favourable. The Property Unit Trust (PUT) sector has performed immensely well and investors can expect a healthy return which, as shown, is considerably higher than other investments. Finally, the fund is being spearheaded by a high calibre DHPF management team, which is key to the listing and management of the fund.
AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die moontlikheid om 'n Diverse Hotel Eiendomsfonds (DHEF) op die Johannesburgse Aandelebeurs te loods. Die huidige aanvangsfase sal in 2005/2006 wees, en sal bestaan uit 'n portfolio van verskillende hotelle wat reg oor Suid-Afrika versprei is. Die navorsing toon dat hoteleiendomsfondse tradisioneel die mees veranderlikste van die Eiendoms Beleggings Trusts (EBT) was en dat die aandeel waarde hoogs afhanklik is van die hotel se inkomste. Nieteenstaande, het investering in DHEFs en EBTs 'n verskeidenheid van voordele soos die voorgeskrewe 90% dividend uitbetalingspersentasie, 'n bestendige kontantvloei en geen korporatiewe inkomstebelasting nie. Die eiendomsbeleggingsfondse sektor in Suid-Afrika het gedurende 2003 'n jaarlikse groei van 39% getoon, en verder beloof die ekonomiese uitkyk in die hotel bedryf om tussen 4% en 5% gedurende 2004 en 2005 onderskeidelik te groei. Gegewe die inligting, is die vraag dus of 'n hoteleiendomsfonds sukses kan behaal in Suid-Afrika en watter opbrengs beleggers kan verwag. Deur na primere empiriese navorsing, sowel as lesse wat geleer is deur beste internasionale praktyke, te bestudeer, identifiseer hierdie verslag sleutel prestasie veranderlikes van EBTs en DHEFs plaas dit in konteks van Suid-Afrika. Hierdie veranderlikes sluit in: kapitaaistruktuur, beleggingsstrategie, risiko en terugkeer, Bruto Bate Waarde (Net Assest Value) (BBW) sowel as aanvanklike openbare aanbod (Initial Public Offering) (AOA). Daar is bevind dat daar geen optimale kapitaalstruktuur vir DHEFs bereken kan word nie. Verder word aangetoon dat daar slegs bepaal kan word of EBTs se struktuur voordelig is wanneer die mark reageer op nuwe skuld wat aangegaan is. Wat beleggingsstrategie betref, is beleggers oor die algemeen meer aangetrokke tot 'n diverse portefeulje van beleggings. Hierdie verslag bevind egter dat daar geen optimale strategie is om in EBTs te bele nie. Daar word verder bevind dat medium- tot langtermyn opbrengste goed vertoon, terwyl prestasie oor die korttermyn wisselvallig is wat gevolglik 'n invloed op beleggers se strategie het. In waardering van risiko en wins, is dit bepaal dat die insluiting van EBT aandele in 'n diverse portfeulje, die maksimum verwagte opbrengs vir elke vlak van risiko verhoog en dat die vlak van fisiko vir elke vlak van die verwagte opbrengs verlaag word. Verder is daar bevind dat die prestasie van EBTs nie noodwendig bepaal word deur batewaarde of -groote nie en klein EBTs kan beleggers vergelykende opbrengste bied. Eerstedag opbrengs vir industriele AOAs presteer beter as die van EBTs. Soortgelyk aan EBTs is daar verskeie voordele aan hotel EBTs wat die ontsluiting en herontplooiing van kapitaal, beleggingsverspreiding en risikoverlaging insluit. Empiriese navorsing dui aan dat hotel EBT's die mees onstabiele van die EBT sektor is. Hotel EBT's verskil wesenlik van ander EBTs in terme van opbrengs en verdienste wat meer divers is in oorsprong en gegenereer word deur korttermyn huurkontrakte. Hotel EBTs word ook gesien as meer bestuursintensief. Net soos met EBTs is daar geen bewyse dat daar 'n optimale kapitaalstruktuur bestaan nie en met die verwagte 50% skuld verhouding, volg DHEF wereldwye beste praktyk. Daar is verskeie nadele aan hotel EBTs, insluitend die laagste dividenduitkeer onder alle EBT sektore, hoe vlakke van onstabiliteit in verdienste, sensitiwiteit vir opswaai en afloop in die toerismemark, groot kapitaalbelegging en hoe vaste operasionele uitgawes op werknemers en infrastruktuur. Die gevolgtrekking is dat ten spyte van negatiewe faktore, die vooruitsig dat DHEF in Suid-Afrika sal slaag, hoog is. Die EBT en hotel EBT mark het bewys dat dit suksesvol is in talle ander groot kapitaalmarkte wat beleggers met 'n verskeidenheid van voordele kan voorsien. Suid-Afrika se ekonomiese- en toerismevooruitsig is baie positief. Die Eiendoms Eenheids Fonds (EEF) sektor het goed vertoon en beleggers kan 'n gesonde opbrengs verwag wat, soos aangedui word, aansienlik hoer is as ander beleggings. Die fonds word gedryf deur 'n hoe kaliber bestuurspan wat krities is tot die notering en die bestuur van fondse.

In the current thesis, the efficiency of the Egyptian and other four MENA exchanges is examined. The first issue of interest is whether market efficiency in Egypt is related to size and regulatory changes. Employing weekly data for the period 1997-2007 and a battery of variance ratio tests (VRs), results indicated that the market was inefficient in pricing all securities during the first sub-period with tight price limits regime, however; it has become efficient in pricing securities, excluding small-capitalized firms, after the expansion of price limits coupled with adopting trading halt for few minutes if prices hit their new limits. The second issue considered is testing for weak-form-efficiency in five MENA exchanges during 1995-2009 using VRs in rolling window estimation to accommodate developments in the underlying exchanges. Results indicate that Turkish and Israeli exchanges are the most efficient throughout the whole period whereas both the Egyptian and Moroccan exchanges moved towards efficiency since late 2002 and the Jordanian exchange experienced inefficiencies during the end of the period. Exchange rates do not matter in determining the dynamics of equity markets examined. The last issue examined is the interdependence and information transmission across super sectors within the same exchange in Egypt, Turkey, and Israel. Multivariate co-integration analysis, which is executed from the domestic investor perspective, indicates the absence of long-term relationship in either exchange. In general, generalised impulse responses indicate that a positive shock in one index in either exchange affects other indexes in the same exchange. However, this impact tapers off quickly. More importantly, most of the impact is on the index experiencing the innovation and the effect on the remaining indexes is relatively small.

The building industry accounts for around one third of the total energy use and GHG emissions in Sweden. Despite the implementation of energy efficiency measures focusing on new buildings, embodied impacts from material extraction, manufacturing, construction and maintenance have grown in significant proportions. While cities like Stockholm are currently experiencing a strong demographic growth and a high pressure on the supply of new spaces and facilities for new residents, national environmental goals aim to reduce energy use and GHG emissions in the coming decades. For instance, the new Climate Act in Sweden expects the country to become carbon neutral by 2045 and the European Commission urges the decarbonisation of national building stocks by 2050. The dual pressure of growth and environmental targets urges the exploration of alternatives for the supply and use of space. In fact, some sources indicate that many spaces remain unused during several hours a day/week and estimations show that most of the buildings that will be in use in 2050 have already been built today. This study explores the potential for a resource-efficient use of space in the existing building stock in Stockholm, leading to a positive impact on the reduction of energy consumption and GHG emissions. The inquiry is conducted with a mixed methods approach in three sequential steps: the identification of relevant stakeholders, instruments and initiatives; the analysis of use of space in a sample of commercial spaces at the street level; and the formulation of strategies allowing an increase in their temporal and spatial capacity. The study suggests that one way to optimise the use of space in existing buildings is to create new property rights. Specifically, it illustrates how merging commercial spaces on the street level through the constitution of 3D properties can increase the capacity to accommodate activities in space and time. Together with digitalisation and the development of new services based on sharing solutions, this opens up new possibilities for decreasing new construction and to absorb new demands for heated floor area.

South African property investment vehicles consist of collective investment schemes in property (CISPs), also known as property unit trusts (PUTs) and property loan stock (PLS) companies. The application of sections 25B(1), 11(s), 10(1)(k)(i)(aa) and 64B(5)(b) of the Income Tax Act 58 of 1962 (“the Act”) and paragraph 67A(1) of the Eighth Schedule to the Act result in these property investment vehicles being taxed based on their legal form, that of a trust versus a company, rather than on their common purpose. The South African Revenue Service recognised these inconsistencies in the 2007/8 budget tax proposals and proposed that it be reviewed. In December 2007, National Treasury released a discussion paper on the reform of the listed property investment sector in South Africa. The discussion paper is aimed at adopting a real estate investment trust (REIT) regime in South Africa to make South African property investment vehicles more attractive to foreign investors as well as to address the current tax inconsistencies and fragmented regulation of the South African listed real estate sector. In this study, the current inconsistent tax treatment of these property investment vehicles is reviewed, both as to how they apply to the property investment vehicle and to their respective investors. This study further reviews how REITs in selected other countries are regulated and taxed and National Treasury’s proposals as to how REITs applicable in South Africa should be regulated and taxed. Copyright
Dissertation (MCom)--University of Pretoria, 2010.
Taxation
unrestricted

This paper reviews theoretical and empirical evidence of asset price movements impact on the real economic activity. A key channel is the wealth effect on consumption. Fluctuations in stock prices and housing prices influence the households wealth and could have important impacts on households consumption. In addition, stock prices may affect corporate sector investments and property prices may affect building activity. Here, the method of cointegration is used to estimate the wealth effect and the investment effect in aggregate time series for Germany after the Reunification in 1990. Moreover, we discuss the role of asset prices in the monetary policy strategy of the ECB.

This thesis attempts to analyze a part of the big and complex process of how intellectual property ownership and technological innovation influence the performance of firms and their revenues. Here I analyze a firm's stock market performance as a function of the quantity and quality of intellectual property (patents) owned by the firm in context of the three US high-technology sectors, Pharmaceuticals, Semiconductors and Wireless. In these sectors, value of a firm is predominantly driven by the technologies which a firm owns. I use citation based indicators and number of claims to measure the quality of patents. This research presents empirical evidence for the hypothesis that in high-tech sectors, companies which generate better quality intellectual property perform better than average in the stock market. I also posit that firms which are producing better quality technologies (good R&D) invest more in R&D regardless of their market performance. Furthermore, though smaller firms get relatively less returns on quality and quantity of innovation, they tend to invest a bigger fraction of their total assets in R&D when they are generating high quality patents. Larger firms enjoy the super-additivity effects in terms of market performance as the same intellectual property gives better returns to them. In addition, returns to R&D are relatively higher in the pharmaceutical industry than semiconductor or wireless industries.

The master´s thesis focuses on the internal guidelines of the company Quaprotek Manufacturing, k. s. The theoretical bases of internal guidelines will be discussed in the first part and the basic concepts. In the second analytical part of the thesis the selected company will be introduce and analyze and the existing internal guidelines will be analyzed and evaluated. In the last part I will propose necessary internal guidelines, draft the formal aspects of the internal directive of the company and adjust the existing directives and create some missing directives.

Syfte: Studien syftar till att visa hur och varför volymen börsnoteringar av fastighetsbolag varierat över tid och hur denna volym har påverkats av det ekonomiska klimatet. Metod: Studien baseras på en kvantitativ metod. Multipel regressionsanalys tillämpas där makroekonomiska faktorers förklaringsvärde för volymen börsintroduktioner av fastighetsbolag undersöks. Teoretisk referensram: Det teoretiska ramverk som används i denna studie har sin primära utgångspunkt i tidigare forskning gjorda på börsnoteringar. Vidare har The Fisher Di Pasquale Wheaton model använts för att få en djupare förståelse för fastighetsbranschens mekanismer. Kopplingen till aktiemarknaden har sitt ursprung i Den effektiva marknadshypotesen tillsammans med The capital demand hypothesis. Resultat: Denna studie finner ett negativt samband mellan antalet introduktioner av fastighetsbolag samt det aktuella ränte- och konjunkturläget. Aktieprisutvecklingen bland fastighetsbolag och volatilitet på fastighetsaktiemarknaden har båda ett positivt samband med antalet introduktioner av fastighetsbolag. Denna studie finner inget samband mellan antalet introduktioner av fastighetsbolag och inflationsnivå.
Objective: This thesis aims to gain a deeper understanding of IPO activity by real estate firms, and why its volume varies over time. The objective is also to obtain the impacts of macroeconomic factors on the volumes of initial public offerings. Method: This study uses a quantitative method were macroeconomic factors will be used as predictors in a multiple regression analysis. Further, IPO volumes of real estate firms will be considered as the constant. Theorethical references: The basic theories that are used in this thesis are Efficient Market Hypothesis, the FDW-model, and The Capital Demand Hypothesis. Previous thesis that covers IPOs are considered as the fundmental basis of this study. Results: The results shows a negative correlation between the IPO volumes of real estate firms, and the interest rate, as well as the economic cycle. Hence, this study finds a positive correlation between stock prices and the volatility at the stock market. The results don’t find any significant correlation between IPO volumes and the inflation rate.

Background: Within real estate companies assets according to IFRS/ IAS 40 should be valued at fair value, to compare with previous valuation criteria according to which real estate should valued at cost. Two models can be used within IAS 40, these are value at cost and fair value. When valued at cost the real estate value in the balance sheet should be specified at cost. The method chosen by the company should be used for all real estate within the company except for the premises used by the company.

Purpose: The purpose of the study is to analyse and evaluate how real estate companies experienced the problems that arose when converting to IAS 40, and to analyse the effects on the companies key ratios as a result of the change of accounting method. Key ratios examined were, return on equity, solvency ratio, P/E-ratio and debt/equity ratio.

Method: The essay is made on a qualitative effort in the form of four interviews with experts within the chosen subject area. The compilation of key ratio is made in a quantitative form and is made up of secondary data. Conclusions: With the implementing of IAS 40 for real estate accounting, the ability to better compare the accounting between real estate companies increased, even though all companies do not account for their real estate in the same way. It appeared that the regulation requirements need to be adjusted and formed in a way that better matches the reality in which real estate companies act. Valuation with fair value proved to have both advantages and disadvantages. The advantage was that the comparability and the fair picture between real estate companies increased. The disadvantage was that the valuation of the fair value gives an increased risk for the real estate companies to be over- or undervalued. A wrong valuation gives a wrong picture of the real estate companies and effects the key ratios in a volatile manner.

Cette thèse porte sur la conception des méthodes robustes de réduction d’ordre de modèles numériques de type Éléments Finis (EF) avec contrôle de la précision. La réduction d’ordre est en général nécessaire pour réduire drastiquement les temps de calcul et permettre ainsi une analyse paramétrique, une étude de faisabilité ou de performance de système (avion, unité de production, procédé complexe, etc). Dans cette étude, la technique de décomposition orthogonale aux valeurs propres (POD) sera utilisée pour construire des modèles réduits locaux. Informatiquement parlant, le “modèle” sera considéré comme une base de données de résultats de calcul avec capacité d’extrapolation et d’interpolation locale. Une stratégie adaptative pour stocker et accéder à la base de données est étudiée en étendant l’algorithme In situ Adaptive Tabulation (ISAT) proposé initialement par Pope. En fonction de l’usage et des exigences en précision des résultats, la base de données est enrichie en ligne (online) par des appels au modèle fin en respectant une précision spécifiée jusqu’à couvrir le domaine paramétrique entier, après quoi l’évaluation d’une solution devient très peu couteuse. L’approche couplée POD-ISAT proposée dans cette thèse fournit une méthode de réduction de modèle EF très performante. La méthodologie est évaluée sur un cas réel de conditionnement d’air en régime stationnaire de cabine d’avion dépendant de plusieurs paramètres de conception (température et vitesse d’entrée d’air, mode de ventilation personnalisée, conductivité thermique du fuselage, etc.). Pour les problèmes d’évolution en temps, nous explorons une piste de chainage de modèles et d’utilisation d’algorithme de parallélisation en temps tel que l’algorithme pararéel initialement proposé par Lions, Maday et Turinici (2001). Nous proposons ici une variante quasi-Newton de l’algorithme pararéel que nous appelons algorithme Broyden-pararéel. Il est appliqué au calcul de la diffusion d’un gaz dans la cabine d’avion. Cette thèse s’insère dans le cadre du projet CSDL (Complex System Design Lab, Fond Unique Interministériel) visant à développer une plate-forme logicielle multidisciplinaire pour la conception de systèmes complexes
In this thesis, an efficient Reduced Order Modeling (ROM) technique with control of accuracy for parameterized Finite Element solutions is proposed. The ROM methodology is usually necessary to drastically reduce the computational time and allow for tasks like parameter analysis, system performance assessment (aircraft, complex process, etc.). In this thesis, a ROM using Proper Orthogonal Decomposition (POD) will be used to build local models. The “model” will be considered as a database of simulation results store and retrieve the database is studied by extending the algorithm In Situ Adaptive Tabulation (ISAT) originally proposed by Pope (1997). Depending on the use and the accuracy requirements, the database is enriched in situ (i.e. online) by call of the fine (reference) model and construction of a local model with an accuracy region in the parameter space. Once the trust regions cover the whole parameter domain, the computational cost of a solution becomes inexpensive. The coupled POD-ISAT, here proposed, provides a promising effective ROM approach for parametric finite element model. POD is used for the low-order representation of the spatial fields and ISAT for the local representation of the solution in the design parameter space. This method is tested on a Engineering case of stationary air flow in an aircraft cabin. This is a coupled fluid-thermal problem depending on several design parameters (inflow temperature, inflow velocity, fuselage thermal conductivity, etc.). For evolution problems, we explore the use of time-parallel strategies, namely the parareal algorithm originally proposed by Lions, Maday and Turinici (2001). A quasi-Newton variant of the algorithm called Broyden-parareal algorithm is here proposed. It is applied to the computation of the gas diffusion in an aircraft cabin. This thesis is part of the project CSDL (Complex System Design Lab) funded by FUI (Fond Unique Interministériel) aimed at providing a software platform for multidisciplinary design of complex systems

The thesis deals with the flow in pipe bends and radial turbines geometries that are commonly found in an Internal Combustion Engine (ICE). The development phase of internal combustion engines relies more and more on simulations as an important complement to experiments. This is partly because of the reduction in development cost and the shortening of the development time. This is one of the reasons for the need of more accurate and predictive simulations. By using more complex computational methods the accuracy and predictive capabilities are increased. The disadvantage of using more sophisticated tools is that the computational time is increasing, making such tools less attractive for standard design purposes. Hence, one of the goals of the work has been to contribute to assess and improve the predictive capability of the simpler methods used by the industry. By comparing results from experiments, Reynolds Averaged Navier-Stokes (RANS) computations, and Large Eddy Simulations (LES) the accuracy of the different computational methods can be established. The advantages of using LES over RANS for the flows under consideration stems from the unsteadiness of the flow in the engine manifold. When such unsteadiness overlaps the natural turbulence the model lacks a rational foundation. The thesis considers the effect of the cyclic flow on the chosen numerical models. The LES calculations have proven to be able to predict the mean field and the fluctuations very well when compared to the experimental data. Also the effects of pulsatile exhaust flow on the performance of the turbine of a turbocharging system is assessed. Both steady and pulsating inlet conditions are considered for the turbine case, where the latter is a more realistic representation of the real flow situation inside the exhaust manifold and turbine. The results have been analysed using different methods: single point Fast Fourier Transforms (FFT), probe line means and statistics, area and volume based Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD).
Denna avhandling behandlar flödet i rörkrökar och radiella turbiner som vanligtvis återfinns i en förbränningsmotor. Utvecklingsfasen av förbränningsmotorer bygger mer och mer på att simuleringar är ett viktigt komplement till experiment. Detta beror delvis på minskade utvecklingskostnader men även på kortare utevklningstider. Detta är en av anledningarna till att man behöver mer exakta och prediktiva simuleringsmetoder. Genom att använda mer komplexa beräkningsmetoder så kan både nogrannheten och prediktiviteten öka. Nackdelen med att använda mer sofistikerade metoder är att beräkningstiden ökar, vilket medför att sådana verktyg är mindre attraktiva för standardiserade design ändamål. Härav, ett av målen med projektet har varit att bidra med att bedöma och förbättra de enklare metodernas prediktionsförmåga som används utav industrin. Genom att jämföra resultat från experiment, Reynolds Averaged Navier-Stokes (RANS) och Large Eddy Simulations (LES) så kan nogrannheten hos de olika simuleringsmetoderna fastställas. Fördelarna med att använda LES istället för RANS när det gäller de undersökta flödena kommer ifrån det instationära flödet i grenröret. När denna instationäritet överlappar den naturligt förekommande turbulensen så saknar modellen en rationell grund. Denna avhandling behandlar effekten av de cykliska flöderna på de valda numeriska modellerna. LES beräkningarna har bevisats kunna förutsäga medelfältet och fluktuationerna väldigt väl när man jämför med experimentell data. Effekterna som den pulserande avgasströmning har på turboladdarens turbin prestanda har också kunnat fastställas. Både konstant och pulserande inlopps randvillkor har används för turbinfallet, där det senare är ett mer realistiskt representation av den riktiga strömningsbilden innuti avgasgrenröret och turbinen. Resultaten har analyserats på flera olika sätt: snabba Fourier transformer (FFT) i enskilda punkter, medelvärden och statistik på problinjer, area och volumsbaserade metoder så som Proper Orthogonal Decomposition (POD) samt Dynamic Mode Decomposition (DMD).

QC 20140919

The present thesis explores the viability of the proper generalised decomposition (PGD) as a tool for parametric studies in a daily industrial environment. Starting from the equations modelling incompressible flows, the separated formulation of the equations, the development of a parametric solver, the implementation in a commercial computational fluid dynamics (CFD) software, OpenFOAM, and a numerical validation are presented. The parametrised Stokes and Oseen flows are used as an initial step to test the applicability of the PGD to flow problems. The rationale for the construc- tion of a separable approximation is described and implemented in OpenFOAM. For the numerical validation of the developed strategy analytical test cases are solved. Then, the parametrised steady laminar incompressible Navier-Stokes equations are considered. The nonintrusive implementation of PGD in OpenFOAM is formulated, focusing on the seamless integration of a reduced order model (ROM) in the framework of an industrially validated CFD software. The proposed strategy exploits classical solution strategies in OpenFOAM to solve the PGD spatial iteration, while the parametric one is solved via a collocation approach. Such nonintrusiveness represents an important step towards the industrialisation of PGD-based approaches. The capabilities of the methodology are tested by applying it to benchmark tests in the literature and solving a parametrised flow control problem in a realistic geometry of interest for the automotive industry. Finally, the PGD framework is extended to turbulent Navier-Stokes problems. The separable form of an industrially popular turbulence model, namely Spalart-Allmaras model, is formulated and a PGD strategy for the construction of a parametric turbulent eddy viscosity is devised. Different im- plementation possibilities in the nonintrusive PGD for parametrised Navier- Stokes equations are explored and the proposed strategy is applied to well-documented turbulent flow control benchmark cases in both two and three dimensions.
La tesis explora la viabilidad del método de reducción de modelos Proper Generalised Decomposition (PGD) como herramienta habitual en un entorno industrial para obtener soluciones de problemas de flujo viscoso incompresible que dependan de parámetros. En este documento, partiendo de las ecuaciones que modelan el flujo viscoso e incompresible, se describe en detalle la formulación en forma separada, espacio-parámetros, de las ecuaciones para el método PGD, se desarrolla el algoritmo de resolución teniendo en cuenta los parámetros, se detalla como realizar la implementación en OpenFOAM, que es un software comercial de dinámica de fluidos computacional (CFD por sus siglas en inglés) y se discuten las validaciones numéricas correspondientes. Como paso previo para probar la viabilidad de la PGD a problemas de interés, se estudian flujos de Stokes y Oseen con datos parametrizados. De esta forma, se desarrollan las bases para la construcción de una aproximación separada, espacio-parámetros, de la solución numérica velocidad-presión, todo ello implementado en OpenFOAM. Para estas formulaciones se valida la aproximación numérica de la estrategia desarrollada con ejemplos cuya solución analítica es conocida, lo que permite analizar los errores cometidos, y se presentan ejemplos numéricos de referencia ampliamente estudiados en la literatura para mostrar su viabilidad. Seguidamente se consideran las ecuaciones de Navier-Stokes para flujo incompresible, estacionario y laminar de nuevo dependiendo de parámetros de diseño. La implementación no intrusiva de la PGD en OpenFOAM está formulada para obtener integración perfecta de un modelo de orden reducido (ROM por sus siglas en inglés) con un software CFD validado industrialmente. La metodología propuesta explota las estrategias de solución clásicas ya existentes en OpenFOAM para resolver la iteración espacial de la PGD, mientras que la iteración de las funciones que dependen de los parámetros se realiza de forma externa a OpenFOAM (empleando formulaciones basadas en la colocación puntual). La no-intrusividad es crítica para una cualquier estrategia que pretenda emplear la formulación PGD en la práctica diaria de la producción y diseño industrial. Para justificar la metodología propuesta así como su viabilidad, se muestra la solución de problemas de referencia clásicos y habituales en la literatura así como la resolución de un problema de control de flujo parametrizado en una geometría realista de interés para la industria de la automoción. Finalmente, es importante resaltar que se extiende a flujos turbulentos la metodología propuesta para trabajar con la PGD de manera no-intrusiva. Más concretamente, las ecuaciones de Navier-Stokes se complementan con un modelo de turbulencia habitual en aplicaciones industriales: el modelo de Spalart-Allmaras. En este caso, se propone una extensión de la estructura separada de las aproximaciones (velocidad y presión), y se diseña una estrategia PGD para la construcción de una viscosidad turbulenta paramétrica. Se exploran diferentes posibilidades de implementación de la PGD no intrusiva para las ecuaciones de Navier-Stokes para flujo turbulento y dependiendo de parámetros. La estrategia propuesta se aplica a casos de referencia de control de flujo turbulento bien documentados en dos y tres dimensiones.

This thesis aims to analyze trends in the area of residential properties within selected locality over a selected period of time. Introduction chapter explains basic terminology of real estate market and later unveils the way how is residential market integrated into real estate market as such. It also describes factors that have significant impact on supply and demand. Next chapter describes residential market and distribution of its particular sectors. Main chapter analyzes selected parameters which affect residential market in the South Moravian Region. Key parameters are demographic movement, income and living standards of residents and its relationship to household, residential construction trends, etc. The final chapter is concerned with housing condition of council flats and houses in the area of Brno metropolis. The analyses contains the trend monitoring of selected factors over a selected period of time.

Afin d'élaborer des stratégies de contrôle des écoulements en temps réel, il est nécessaire d'avoir recours à des modèles d'ordre réduit (ROMs), car la résolution des équations complètes est trop coûteuse en temps de calcul (des jours, des semaines) et en espace mémoire. Dans cette thèse, les modèles réduits ont été construits avec la méthode POD (Proper Orthogonal Decomposition). Une méthode de projection basée sur la minimisation des résidus, initiée par les travaux de Leblond et al. [134] a été proposée. Dans certaines configurations, la précision des résultats est significativement augmentée, par rapport à une projection de Galerkin classique. Dans un second temps, un algorithme d'optimisation non-linéaire, à direction de descente basée sur la méthode des équations adjointes, a été couplé avec des modèles réduits utilisant des bases POD. Deux méthodes de construction de base POD ont été employées : soit avec un paramètre (un nombre de Reynolds,. . . ), soit avec plusieurs paramètres (plusieurs nombres de Reynolds, . . . ). Les ROMs obtenus ont été utilisés pour contrôler la dispersion d'un polluant dans une cavité ventilée puis pour contrôler le champ de température dans une cavité entraînée différentiellement chauffée. Le contrôle est réalisé en temps quasi-réel et les résultats obtenus sont plutôt satisfaisants. Néanmoins, ces méthodes sont encore trop coûteuses en espace mémoire pour être aujourd'hui embarquées dans les boîtiers de contrôle utilisés dans le bâtiment. Une autre stratégie de contrôle, s'appuyant sur les contrôleurs actuels, a ainsi été développée. Celle-ci permet d'obtenir la température (ainsi que la vitesse) dans la zone d'occupation du bâtiment, en utilisant une décomposition des champs par POD et un algorithme d'optimisation de Levenberg-Marquardt. Elle a été validée sur une cavité différentiellement chauffée, puis appliquée sur une cavité ventilée 3D, proche d'un cas réel.

Le coût d’une simulation numérique aéroélastique peut devenir trop onéreuse lorsque une analyse paramétrique à haut fidélité est requise. Dans ce contexte, des Modèles d'Ordre Réduit (MOR) ont été développés en vue de réduire le coût de calcul des simulations numériques en préservant un haut niveau de précision. Ce travail de thèse porte sur la construction d'un MOR pour les équations de Navier-Stokes en tenant compte d'un maillage déformable dans le cas d'une application aéroélastique. Une base modale pour l'écoulement est obtenue via la Décomposition Orthogonale aux valeurs propres et une projection Galerkin est utilisée pour réduire le système d'équations de la mécanique des fluides. Pour pouvoir prendre en compte les non-linéarités des équation de Navier-Stokes une méthode de projection masquée est mise en œuvre et évaluée pour différent cas test avec maillage fixe. Le MOR est ensuite adapté pour prendre en compte des maillages déformables. Finalement, une méthode réduite spectrale en temps (ROTSM) a été formulée afin de répondre aux problèmes de stabilité qui concernent le MORs avec projection dans le domaine de la mécanique des fluides. Une évaluation du MOR obtenu est ensuite menée sur des études paramétriques pour des applications aéroélastiques
The numerical prediction of aeroelastic systems responses becomes unaffordable when parametric analyses with high-fidelity CFD are required. Reduced order modeling (ROM) methods have therefore been developed in view of reducing the costs of the numerical simulations while preserving a high level of accuracy. The present thesis focuses on the family of projection based methods for the compressible Navier-Stokes equations involving deforming meshes in the case of aeroelastic applications. A vector basis obtained by Proper Orthogonal Decomposition (POD) combined to a Galerkin projection of the system equations is used in order to build a ROM for fluid mechanics. Masked projection approaches are therefore implemented and assessed for different test cases with fixed boundaries in order to provide a fully nonlinear formulation for the projection-based ROMs. Then, the ROM is adapted in the case of deforming boundaries and aeroelastic applications in a parametric context. Finally, a Reduced Order Time Spectral Method (ROTSM) is formulated in order to address the stability issues which involve the projection-based ROMs for fluid mechanics applications

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O BNDES tem o objetivo de financiar empreendimentos que se relacionem com o desenvolvimento do país, sendo uma de suas modalidades o investimento por subscrição de ações. De um lado, tem-se que as regras elaboradas na estruturação societária de uma empresa podem variar de acordo com a origem do financiamento obtido, em função dos interesses que os diferentes investidores procuram proteger a partir da separação entre a sua propriedade e o controle. Por outro lado, o cenário econômico brasileiro passou por mudanças profundas nos últimos 60 anos, já que o modelo de industrialização baseado no dirigismo estatal – que marcou as décadas de 1950 a 1980 – transformou-se com o movimento de desestatização dos anos 1990. O Estado não se afastou da propriedade empresarial, mas atua agora principalmente como acionista minoritário. Hoje, paira dúvida acerca, em primeiro lugar, das reais motivações que levam determinadas empresas a receber participação do Sistema BNDES. Além disso, há pouca compreensão sobre os veículos jurídicos que viabilizam essas relações público-privadas. A partir de algumas pesquisas sobre o banco, conclui-se que a atuação da sua subsidiária de participações, a BNDESPAR, não ultrapassa objetivos de maximização de valor dos seus ativos. Não se descartou, no entanto, que a função do banco de desenvolvimento – incluindo a do seu braço de renda variável – fosse implementar políticas industriais, por mais que falhas pudessem vir a ocorrer nesse intento, reconhecido como um processo experimental. Assim, revelou-se quais interesses as regras de governança corporativa das companhias abertas financiadas pela BNDESPAR por participação acomodam para a subsidiária, elucidando-se importantes características do modelo contemporâneo de atuação empresarial do Estado e lançando-se luz sobre os objetivos que o levam a investir diretamente como acionista no cenário atual. No caso da BNDESPAR, trata-se de agente em busca de equilíbrio entre a maximização de retornos e a política industrial. De uma maneira mais geral, o BNDES procura ser auto-sustentável – como pré-requisito para existir e cumprir sua missão –, tratando sua subsidiária como a principal personagem desse objetivo dentro do Sistema. A BNDESPAR, por sua vez, acabou por se tornar executora de política voltada a apoiar a negociação das companhias brasileiras no mercado de capitais – atividade emanada da sua própria burocracia.
BNDES has the objective of financing projects related to Brazil’s development and equity purchases are one of its types of investment. On one hand, rules drawn up in a company’s corporate governance structure can vary according to the capital’s origin, since different interests that different investors seek to protect emerge from the separation of their property from the corporate control. On the other hand, Brazilian economic scenario went trough deep changes over the last 60 years, considering that the industrialization model based on State intervention, mainstream between the 1950s and the 1980s, was transformed by the privatization movement in the 1990s. This change, however, did not eliminate the State in corporate property: now it only acts more commonly as a minority shareholder. The present time is marked by doubt over the real motivation that leads some companies to receive equity investments by the BNDES System. Besides that, there is a lack of comprehension on the contractual vehicles that structure these public-private relations. Some researches concerning the bank indicate that its subsidiary investments would not undermine the objective for profit maximization. We have not ignored, however, that the development bank function – including its equity arm – might be executing industrial policies, even though failures are likely to occur during this effort, understood here as an experimental process. Thus, the research has revealed which BNDESPAR’s interests are protected through the corporate governance rules of the public traded companies invested, also revealing important features of the contemporary model of the State as an entrepreneur and clarifying some objectives that could lead the institution to purchase equity participations nowadays. BNDESPAR is an agent motivated by a balance pursuit between profit maximization and industrial policy purposes. Broadly speaking, BNDES seeks self-financial sustainability in order to continue and accomplish its mission, seeing its equity arm as the main executor of this objective inside its System. In this search for sustainability, BNDESPAR became executor of a policy effort for stock markets negotiation raised up among its own bureaucracy activities.

The subject of this thesis is to introduce the reader to the issue of possible financial investment in the virtual economy with real funds and design strategies to maximize the initial capital appreciation. The introduction describes the analysis of virtual PED currency, the economy and the system of publicly traded shares. The main part is focused on presenting the results of practical traded investment based on fundamental analysis, speculation about the intrinsic value of the shares and evaluating applied strategies, including the benefits of work.

L'objectif de ce travail consiste à développer la méthode de résolution PGD (Proper Generalized Decomposition), qui est une méthode de réduction de modèle où la solution est recherchée sous forme séparée, à la résolution des équations de Navier-Stokes. Dans un premier temps, cette méthode est appliquée à la résolution d'équations modèles disposant d'une solution analytique. L' équation de diffusion stationnaire 2D et 3D, l'équation de diffusion instationnaire 2D et les équations de Burgers et Stokes sont traitées. Nous montrons que dans tous ces cas la méthode PGD permet de retrouver les solutions analytiques avec une précision équivalente au modèle standard. Nous mettons également en évidence la supériorité de la PGD par rapport au modèle standard en terme de temps de calcul. En effet, dans tous ces cas, laPGD se montre beaucoup plus rapide que le solveur standard (plusieurs dizaine de fois). La résolution des équations de Navier-Stokes isothermes et anisothermes est ensuite effectuée par une discrétisation volumes finis sur un maillage décalé où le couplage vitesse-pression a été géré à l'aide d'un schéma de prédiction-correction. Dans ce cas une décomposition PGD sur les variables d'espaces uniquement a été choisie. Pour les écoulements incompressibles 2D stationnaire ou instationnaire, de type cavité entrainée et/ou différentiellement chauffé, les résultats obtenus par résolution PGD sont similaires à ceux du solveur standard avec un gain de temps significatif (la PGD est une dizaine de fois plus rapide que le solveur standard). Enfin ce travail introduit une première approche de la résolution des équations de transferts par méthode PGD en formulation spectrale. Sur les différents problèmes traités, à savoir l'équation de diffusion stationnaire, l'équation de Darcy et les équations de Navier-Sokes, la PGD a montré une précision aussi bonne que le solveur standard. Un gain de temps a été observé pour le cas de l'équation de Poisson, par contre, concernant le problème de Darcy ou les équations de Navier-Stokes les performances de la PGD en terme de temps de calcul peuvent encore être améliorées.

[ES] El principal desafío en los motores turbina de gas empleados en aviación reside en aumentar la eficiencia del ciclo termodinámico manteniendo las emisiones contaminantes por debajo de las rigurosas restricciones. Ésto ha conllevado la necesidad de diseñar nuevas estrategias de inyección/combustión que operan en puntos de operación peligrosos por su cercanía al límite inferior de apagado de llama. En este contexto, el concepto Lean Direct Injection (LDI) ha emergido como una tecnología prometedora a la hora de reducir los óxidos de nitrógeno (NOx) emitidos por las plantas propulsoras de los aviones de nueva generación. En este contexto, la presente tesis tiene como objetivos contribuir al conocimiento de los mecanismos físicos que rigen el comportamiento de un quemador LDI y proporcionar herramientas de análisis para una profunda caracterización de las complejas estructuras de flujo de turbulento generadas en el interior de la cámara de combustión. Para ello, se ha desarrollado una metodología numérica basada en CFD capaz de modelar el flujo bifásico no reactivo en el interior de un quemador LDI académico mediante enfoques de turbulencia U-RANS y LES en un marco Euleriano-Lagrangiano. La resolución numérica de este problema multi-escala se aborda mediante la descripción completa del flujo a lo largo de todos los elementos que constituyen la maqueta experimental, incluyendo su paso por el swirler y entrada a la cámara de combustión. Ésto se lleva a cabo través de dos códigos CFD que involucran dos estrategias de mallado diferentes: una basada en algoritmos de generación y refinamiento automático de la malla (AMR) a través de CONVERGE y otra técnica de mallado estático más tradicional mediante OpenFOAM. Por un lado, se ha definido una metodología para obtener una estrategia de mallado óptima mediante el uso del AMR y se han explotado sus beneficios frente a los enfoques tradicionales de malla estática. De esta forma, se ha demostrado que la aplicabilidad de las herramientas de control de malla disponibles en CONVERGE como el refinamiento fijo (fixed embedding) y el AMR son una opción muy interesante para afrontar este tipo de problemas multi-escala. Los resultados destacan una optimización del uso de los recursos computacionales y una mayor precisión en las simulaciones realizadas con la metodología presentada. Por otro lado, el uso de herramientas CFD se ha combinado con la aplicación de técnicas de descomposición modal avanzadas (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificación numérica de los principales modos acústicos en la cámara de combustión ha demostrado el potencial de estas herramientas al permitir caracterizar las estructuras de flujo coherentes generadas como consecuencia de la rotura de los vórtices (VBB) y de los chorros fuertemente torbellinados presentes en el quemador LDI. Además, la implementación de estos procedimientos matemáticos ha permitido tanto recuperar información sobre las características de la dinámica de flujo como proporcionar un enfoque sistemático para identificar los principales mecanismos que sustentan las inestabilidades en la cámara de combustión. Finalmente, la metodología validada ha sido explotada a través de un Diseño de Experimentos (DoE) para cuantificar la influencia de los factores críticos de diseño en el flujo no reactivo. De esta manera, se ha evaluado la contribución individual de algunos parámetros funcionales (el número de palas del swirler, el ángulo de dichas palas, el ancho de la cámara de combustión y la posición axial del orificio del inyector) en los patrones del campo fluido, la distribución del tamaño de gotas del combustible líquido y la aparición de inestabilidades en la cámara de combustión a través de una matriz ortogonal L9 de Taguchi. Este estudio estadístico supone un punto de partida para posteriores estudios de inyección, atomización y combus
[CA] El principal desafiament als motors turbina de gas utilitzats a la aviació resideix en augmentar l'eficiència del cicle termodinàmic mantenint les emissions contaminants per davall de les rigoroses restriccions. Aquest fet comporta la necessitat de dissenyar noves estratègies d'injecció/combustió que radiquen en punts d'operació perillosos per la seva aproximació al límit inferior d'apagat de flama. En aquest context, el concepte Lean Direct Injection (LDI) sorgeix com a eina innovadora a l'hora de reduir els òxids de nitrogen (NOx) emesos per les plantes propulsores dels avions de nova generació. Sota aquest context, aquesta tesis té com a objectius contribuir al coneixement dels mecanismes físics que regeixen el comportament d'un cremador LDI i proporcionar ferramentes d'anàlisi per a una profunda caracterització de les complexes estructures de flux turbulent generades a l'interior de la càmera de combustió. Per tal de dur-ho a terme s'ha desenvolupat una metodología numèrica basada en CFD capaç de modelar el flux bifàsic no reactiu a l'interior d'un cremador LDI acadèmic mitjançant els enfocaments de turbulència U-RANS i LES en un marc Eulerià-Lagrangià. La resolució numèrica d'aquest problema multiescala s'aborda mitjançant la resolució completa del flux al llarg de tots els elements que constitueixen la maqueta experimental, incloent el seu pas pel swirler i l'entrada a la càmera de combustió. Açò es duu a terme a través de dos codis CFD que involucren estratègies de mallat diferents: una basada en la generación automàtica de la malla i en l'algoritme de refinament adaptatiu (AMR) amb CONVERGE i l'altra que es basa en una tècnica de mallat estàtic més tradicional amb OpenFOAM. D'una banda, s'ha definit una metodologia per tal d'obtindre una estrategia de mallat òptima mitjançant l'ús de l'AMR i s'han explotat els seus beneficis front als enfocaments tradicionals de malla estàtica. D'aquesta forma, s'ha demostrat que l'aplicabilitat de les ferramente de control de malla disponibles en CONVERGE com el refinament fixe (fixed embedding) i l'AMR són una opció molt interessant per tal d'afrontar aquest tipus de problemes multiescala. Els resultats destaquen una optimització de l'ús dels recursos computacionals i una major precisió en les simulacions realitzades amb la metodologia presentada. D'altra banda, l'ús d'eines CFD s'ha combinat amb l'aplicació de tècniques de descomposició modal avançades (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificació numèrica dels principals modes acústics a la càmera de combustió ha demostrat el potencial d'aquestes ferramentes al permetre caracteritzar les estructures de flux coherents generades com a conseqüència del trencament dels vòrtex (VBB) i dels raigs fortament arremolinats presents al cremador LDI. A més, la implantació d'estos procediments matemàtics ha permès recuperar informació sobre les característiques de la dinàmica del flux i proporcionar un enfocament sistemàtic per tal d'identificar els principals mecanismes que sustenten les inestabilitats a la càmera de combustió. Finalment, la metodologia validada ha sigut explotada a traves d'un Diseny d'Experiments (DoE) per tal de quantificar la influència dels factors crítics de disseny en el flux no reactiu. D'aquesta manera, s'ha avaluat la contribución individual d'alguns paràmetres funcionals (el nombre de pales del swirler, l'angle de les pales, l'amplada de la càmera de combustió i la posició axial de l'orifici de l'injector) en els patrons del camp fluid, la distribució de la mida de gotes del combustible líquid i l'aparició d'inestabilitats en la càmera de combustió mitjançant una matriu ortogonal L9 de Taguchi. Aquest estudi estadístic és un bon punt de partida per a futurs estudis de injecció, atomització i combustió en cremadors LDI.
[EN] Aeronautical gas turbine engines present the main challenge of increasing the efficiency of the cycle while keeping the pollutant emissions below stringent restrictions. This has led to the design of new injection-combustion strategies working on more risky and problematic operating points such as those close to the lean extinction limit. In this context, the Lean Direct Injection (LDI) concept has emerged as a promising technology to reduce oxides of nitrogen (NOx) for next-generation aircraft power plants In this context, this thesis aims at contributing to the knowledge of the governing physical mechanisms within an LDI burner and to provide analysis tools for a deep characterisation of such complex flows. In order to do so, a numerical CFD methodology capable of reliably modelling the 2-phase nonreacting flow in an academic LDI burner has been developed in an Eulerian-Lagrangian framework, using the U-RANS and LES turbulence approaches. The LDI combustor taken as a reference to carry out the investigation is the laboratory-scale swirled-stabilised CORIA Spray Burner. The multi-scale problem is addressed by solving the complete inlet flow path through the swirl vanes and the combustor through two different CFD codes involving two different meshing strategies: an automatic mesh generation with adaptive mesh refinement (AMR) algorithm through CONVERGE and a more traditional static meshing technique in OpenFOAM. On the one hand, a methodology to obtain an optimal mesh strategy using AMR has been defined, and its benefits against traditional fixed mesh approaches have been exploited. In this way, the applicability of grid control tools available in CONVERGE such as fixed embedding and AMR has been demonstrated to be an interesting option to face this type of multi-scale problem. The results highlight an optimisation of the use of the computational resources and better accuracy in the simulations carried out with the presented methodology. On the other hand, the use of CFD tools has been combined with the application of systematic advanced modal decomposition techniques (i.e., Proper Orthogonal Decomposition and Dynamic Mode Decomposition). The numerical identification of the main acoustic modes in the chamber have proved their potential when studying the characteristics of the most powerful coherent flow structures of strongly swirled jets in a LDI burner undergoing vortex breakdown (VBB). Besides, the implementation of these mathematical procedures has allowed both retrieving information about the flow dynamics features and providing a systematic approach to identify the main mechanisms that sustain instabilities in the combustor. Last, this analysis has also allowed identifying some key features of swirl spray systems such as the complex pulsating, intermittent and cyclical spatial patterns related to the Precessing Vortex Core (PVC). Finally, the validated methodology is exploited through a Design of Experiments (DoE) to quantify the influence of critical design factors on the non-reacting flow. In this way, the individual contribution of some functional parameters (namely the number of swirler vanes, the swirler vane angle, the combustion chamber width and the axial position of the nozzle tip) into both the flow field pattern, the spray size distribution and the occurrence of instabilities in the combustion chamber are evaluated throughout a Taguchi's orthogonal array L9. Such a statistical study has supposed a good starting point for subsequent studies of injection, atomisation and combustion on LDI burners.
Belmar Gil, M. (2020). Computational study on the non-reacting flow in Lean Direct Injection gas turbine combustors through Eulerian-Lagrangian Large-Eddy Simulations [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159882
TESIS

This thesis develops a one-dimensional version of a new data driven model of turbulence that uses the KL expansion to provide a spectral solution of the turbulent flow field based on analysis of Particle Image Velocimetry (PIV) turbulent data. The analysis derives a 2nd order random field over the whole flow domain that gives better turbulence properties in areas of non-uniform flow and where flow separates than the present models that are based on the Navier-Stokes Equations. These latter models need assumptions to decrease the number of calculations to enable them to run on present day computers or super-computers. These assumptions reduce the accuracy of these models. The improved flow field is gained at the expense of the model not being generic. Therefore the new data driven model can only be used for the flow situation of the data as the analysis shows that the kernel of the turbulent flow field of undular hydraulic jump could not be related to the surface waves, a key feature of the jump. The kernel developed has two parts, called the outer and inner parts. A comparison shows that the ratio of outer kernel to inner kernel primarily reflects the ratio of turbulent production to turbulent dissipation. The outer part, with a larger correlation length, reflects the larger structures of the flow that contain most of the turbulent energy production. The inner part reflects the smaller structures that contain most turbulent energy dissipation. The new data driven model can use a kernel with changing variance and/or regression coefficient over the domain, necessitating the use of both numerical and analytical methods. The model allows the use of a two-part regression coefficient kernel, the solution being the addition of the result from each part of the kernel. This research highlighted the need to assess the size of the structures calculated by the models based on the Navier-Stokes equations to validate these models. At present most studies use mean velocities and the turbulent fluctuations to validate a models performance. As the new data driven model gives better turbulence properties, it could be used in complicated flow situations, such as a rock groyne to give better assessment of the forces and pressures in the water flow resulting from turbulence fluctuations for the design of such structures. Further development to make the model usable includes; solving the numerical problem associated with the double kernel, reducing the number of modes required, obtaining a solution for the kernel of two-dimensional and three-dimensional flows, including the change in correlation length with time as presently the model gives instant realisations of the flow field and finally including third and fourth order statistics to improve the data driven model velocity field from having Gaussian distribution properties. As the third and fourth order statistics are Reynolds Number dependent this will enable the model to be applied to PIV data from physical scale models. In summary, this new data driven model is complementary to models based on the Navier-Stokes equations by providing better results in complicated design situations. Further research to develop the new model is viewed as an important step forward in the analysis of river control structures such as rock groynes that are prevalent on New Zealand Rivers protecting large cities.

La présente étude a pour objet de montrer que les moyens de la protection des actionnaires minoritaires en droit chinois et en droit français ne sont pas soumis à des critères fondamentalement différents. Dans les sociétés anonymes, les règles juridiques visent à trouver un équilibre des rapports entre les actionnaires majoritaires et minoritaires, ainsi qu’entre les actionnaires et la société ou le groupe de sociétés.C’est l’intérêt social et le principe d’égalité qui guident le législateur et le juge de proposer des solutions convenables.Il importe de noter qu’en droit français, les dispositions sur les responsabilités et les moyens de recours pour les minoritaires sont d’applications faciles qu’en droit chinois. D’ailleurs, la recherche de l’acquisition des sociétés cotées chinoises sous l’angle de la protection des minoritaires, tout à fait différent à l’offre publique en droit français, présente les particularités du marché réglementé chinois et mérite que les investisseurs étrangers découvrent davantage
The dissertation aimed to point out that the methods of the protection of minority shareholders in Chinese law and in French law are not subject to the different criteria. In company limited by shares, the legal provisions intend to find a balance of relation between majority shareholders and minority shareholders, and between the shareholders and the company or group of company. It is corporate profits and the principal of equality that direct legislators and judges to suggest applicable solutions.It is important to notify that in French law, legal provisions about the responsibility of majority shareholders or company leaders and the ways of resort of minority shareholders provide reference for improvement of Chinese law. Besides, the study of acquisition of chinese listed companies, looked from the angle of the protection of minority shareholders, very different from tender offer in French law, demonstrate the characteristics of Chinese stock market and deserve foreign investors’ enough attention

碩士
國立中山大學
財務管理學系研究所
96
These theses whether examine the property stock investors are overconfident or underconfident. This thesis firstly use VAR model and the empirical result shows that the property stock investors existed overconfidence investment behavior in the bull market, especially in low-price stock. However, this kind of behavior does not exist in the bear market. The result also shows that most of turnover rate are driven by market return rather than property stock return. this represents investors purchase (or sell) the property stock is caused by the market goes up (or down) rather than have perspective in the property stock. The result implied the property stock investor had speculative trading in short term. In long term, investors have insufficient faith in the real estate market. Next, this thesis use EGARCH and the result shows that the overconfidence investors’ excessive trading will increase volatility, and will harm the development of industry. Finally, we discussed the main factor of investors’ underconfidence in property industry, found political environment as well as long recession are the factors.

This research project examines the investment performance of Hong Kong?s real estate and property stocks over a period of nineteen years from 1984 to 2002. Evaluations using time-varying Jensen index adjust the asset return comparison for possible time-varying investment risk (return variation). The return and risk comparison for direct and indirect real estate investment is further investigated with an alternative GARCH-M model in capturing the possible time-varying risk premium. Unlike previous studies, one of the major contributions of this research is to measure the risk-adjusted real estate returns by taking into account the impact of illiquidity, management and transaction costs, and vacancy risk with actual transaction data. The time-varying models have not been applied for analysing the returns on property investment in Hong Kong so far. The results of this study help resolving the puzzle why real estate offers superior investment performance as stated in the existing literature that is inconsistent with the Efficient Market Hypothesis. With arbitrage, the capital theory predicts that all investments should display similar risk adjusted return in the long run. As a result, it is impossible for direct property to earn abnormal risk adjusted return in the long run. The empirical results show that superiority of real estate property in risk-adjusted return is reduced or even disappeared in the period of 1991 to 2002 when the impact of illiquidity and the 1997 Asian Financial Crisis are taken into account. This conclusion is further strengthened with the favourable empirical evidence obtained when all the unsystematic risks including the management and transaction costs, and vacancy risk are incorporated into the analysis. The superior investment performance for real estate relative to property stocks found in the literature is too good to be true. Its existence is simply due to the omission of fundamentals factors like unsystematic risks in the analysis. The impact of liquidity on return assessment has been under-researched, this study attempts to fill the gap by quantifying the impact of liquidity explicitly in explaining the excess return of real estate investment. The empirical result is consistent with the intuition that investors require compensation in holding illiquid assets.

碩士
國立中山大學
經濟學研究所
100
As the price level soars up, it become more important to study the dynamic relation between stock prices, price indices. In this paper we suspect that property stocks serve as tools of anti-inflation and examine whether there exists a positive correlation between the prices of property stocks and price indices, such as the Rent Index, CPI, and WPI. Our results confirm the positive correlation between the prices of property stocks and the price indices. More precisely, it is revealed by applying VAR and the impulse response analysis that the positive correlation between the prices of property stocks and CPI/WPI in the short run. Using the cointegration analysis, we detect the long-run relation between the prices of property stocks and the Rent Index.

碩士
淡江大學
財務金融學系碩士在職專班
103
With housing prices continue rising, the government had introduced several housing control measures since 2010 in an effort to strengthen the real estate market. A part of these measures was to limit the lending activities through the Central Bank regulations to suppress rising prices. This study utilizes Event Study Method to analyze if there are negative impacts on listed construction stocks on each of the control measure implemented by the Central Bank. The results indicate that the stock prices of construction stocks would have been impacted when the Central Bank introduce its housing control measures. Specifically, when the Central Bank introduced tighter measures on property and land financing in the targeted areas, investors deem these messages as negative for construction stocks. However, not all measures impact the construction stocks negatively. When the Central Bank announce to raise the rediscount rate, the rate on accommodations with collateral, and the rate on accommodations without collateral, the construction stocks respond positively.

碩士
國立虎尾科技大學
財務金融系碩士班
104
This study will examine the implementation of the luxury tax, actual price registration, four selective credit controls and the interest rate the central bank to raise interest rates four categories of housing policy to fight construction industry related stocks, the effect of the degree of influence. The results of this study show: Overall, the fiscal policy section: to suppress the price effect is concerned, the relevant stocks affect the results construction industry construction industry class luxury tax has a negative impact on the negative cumulative abnormal returns for the biggest and the cement industry stocks is actual price registration respectively negative cumulative abnormal returns for the maximum. During the early part of its impact prior to implementation of the policy reaction had been consumed, then the effect is not ideal. Monetary policy: The main impact of short-term effect, unless external factors (announcement effect, synergistic effects of other events ... etc). In order to suppress the price point of view, selective credit control to the Construction industry stocks substantially affect the largest cumulative average abnormal returns; central bank interest rate hike impact on the construction industry stocks cumulative average abnormal returns maximized. Its point of view on the event day, monetary policy is relatively greater cumulative average abnormal returns than fiscal policy affect the results.

碩士
中國文化大學
財務金融學系
101
When a Taiwanese company has a lot of real estates, then the company's stock is normally called "asset stock". The thesis puts the focus on exploring the features of systematic risk and return on “asset stock”. Regarding with systematic risk of “asset stock”, there are several findings. Firstly, “asset stock” has a higher average rate of return but with less risk in the past 14 years. That is, “asset stock” is a relatively worthy investment, while compared with “construction stock”. Secondly, the systematic risk on “asset stock” is continuously changing but less volatile. Thirdly, the structural changes in unstable systematic risk on “asset stock” did exist at some particular time points, where big events happened. Therefore, the “big events” help us in explaining the dynamic process of “asset stock returns”. Factors affecting the assets stock return are divided into risk factors, economic factors and big events. In the risk section, the monthly moving average β is used. As for economic factors, the study uses the consumer price index, interest rate, exchange rate, money supply and the stock market index. The regression result shows, the rate of return on stock market has a significant positive impact on "asset stock return", while both interest rate and exchange rate have negative impacts on "asset stock return". Furthermore, the happenings of big events, such as SARs epidemic, and Lehman Brothers' Bankruptcy, hurt the "asset stock return" of the same month. Last but not least, “monthly moving β” is not important in explaining "asset stock returns”. The result remains the same whether the current monthly moving β or the previous month's moving β was used as an explanatory variable.

The primary purpose of the study is to carry out an investigation into the role of listed real estate stocks in a mixed asset class investment portfolio in South Africa and what weighting should be allocated to this asset class. The study involved collecting data from the last ten years from January 1995 to December 2004 and then comparing the data against data collected from the investment management industry, especially those entities with exposure to direct property and listed property stock holdings over long periods. The study investigates the benefits of listed property stocks in an investment portfolio in South Africa, and empirically tests the data collected using the mean-variance theory to determine the impact of listed property stocks on the performance (maximising returns) and risk (minimising risk) of investment portfolios. The Elton and Gruber computer programme is used to test the data to give an optimal weighting to the sector and produce an efficient frontier. The weightings are then used to work out the efficiency of a portfolio as a result of the inclusion of listed property stocks, and comparing it to a portfolio of just two asset classes, namely equities and bonds, at 75% and 25% weightings respectively. The results demonstrated the benefits offered by listed real estate and revealed that the sector should be treated as a separate asset class from equities due to lower correlation of returns between these two asset classes. It also demonstrated that an increased allocation to the listed property sector would have resulted in better investment performance over the past ten years. The conclusions consistently pointed to the increased asset allocation of listed real estate in investment portfolios as the best long-term solution to diversification and volatility, as long as the liquidity and size of the sector improves. It is concluded in this study, that investment managers have underscored the relevance and allocation of listed real estate in investment portfolios in the past ten years, thus not optimising the performance and risk of their portfolios, as expected in retirement fund portfolios to the benefits of the members.
Thesis (MBA)-University of KwaZulu-Natal, 2006.

The disclosure of headline earnings is one of the JSE Limited (JSE)’s listing requirements. All listed entities are required to comply with this disclosure requirement. Guidance in the form of The Circular on headline earnings is issued by the South African Institute of Chartered Accountants (SAICA), and is updated every time when there are changes to the International Financial Reporting Standards (IFRS). The Circular adopts a rules-based approach and specifies what is included and excluded in the calculation of headline earnings. The rules consist of general rules, which apply to all entities other than those industry groups with special provisions such as the life insurance entities. This study questions whether a rules-based headline earnings approach or a principles-based approach is more appropriate for the calculation of headline earnings of listed property entities on the JSE, for economic decision-making purposes. The research method consisted of questionnaires that were sent out to stakeholders. The responses from the CFOs and investment analysts show that principles-based headline earnings guidance is preferred over rules-based headline earnings guidance.
Business Management
M. Phil (Accounting Sciences)