Comparative Analysis of Viscoelastic Models Involving Fractional Derivatives of Different Orders

Mathematics Subject Classification: 74D05, 26A33

A Public-Private Partnership strukturális modelljeinek összevetése = Comparison of Public-Private Partnership models

A tanulmány a PPP különböző strukturális modelljeinek csoportosítását mutatja be, az egyes típusok rövid rendszerező áttekintésével. A tipológiák vizsgálata hasznos ahhoz, hogy a PPP projektek struktúrájának kialakításakor a különböző lehetőségeket mérlegelni tudjuk. Többféle megközelítésben lehet a modelleket tipizálni. Az együttműködés célja alapján a hatékonyság-, a minőség- és a finanszírozás-orientált modellek a legelterjedtebbek, a kockázatmegosztás módja alapján BOT, DBFO és koncessziós változatok, a haszonmegosztás szabályozása alapján árplafon-szabályozású, közvetlen haszonszabályozású, fixdíjas és árnyékáras megoldások a leginkább bevettek. A tanulmány ezek elemző bemutatása alapján arra a következtetésre jut, hogy a gyakorlati megoldások a legtöbb esetben az elméleti típusok valamilyen kombinációját tartalmazzák, a konkrét eset feltételeinek megfelelően. Így a gyakorlatban a fix tipológiák helyett alkalmasabb úgy megközelítenünk a PPP-t, mint egy folyamatosan változó, a helyi igényekhez idomuló jelenséget. A haszonszabályozó tipológia kapcsán a tanulmány melléklete rövid áttekintést nyújt a PPP esetében kritikus méltányos haszon becslésének lehetséges megoldásairól is. = This study shows a categorization of the different structural models of Public-Private Partnership (PPP) projects. The typologies are useful to assess the available options when decisions on PPP project structures are made. There are different categorizing aspects. Based ont he key purpose of the partnership there are efficiency, quality and financing focused models. From a risk sharing point of view, BOT, DBFO and concession models are most typical. Regarding the regulation of returns price-cap models, ’open book’ models, fixed price and shadow pricing models are most common. Based on the analytical assessment of these, they study concludes that actual projects are mostly a combination of theoretical types, as required by the given case. Therefore in practice, it is more appropriate to approach PPP projects as a constantly shaping concept, adjustable to particular conditions. Supporting the approaches to the regulation of returns, an appendix of the study summarizes the different methods to estimate fair returns, a critical issue in PPP projects.

A magyar vállalatok nemzetközivé válása = Internationalization of Hungarian Companies

A magyar vállalatok nemzetközivé válása kutatási alprojekt a hazai vállalatok nemzetközivé válásának tényeit, kiváltó tényezőit, valamint annak sikertényezőit kutatta. A kutatás keretében elkészült három műhelytanulmány eltérő nézőpontból és különböző módszerekkel vizsgálta a témát. A vezetői összefoglaló a tanulmányok módszereit és fő eredményeit foglalja össze. _______ Subproject of Internationalization of Hungarian Companies focused on the motivating factors, facts and key success factor of the process of becoming international. Three working papers were published in the present phase of the research program reviewing the subject from different aspects and with different methods. The present management summary summarizes the methods and main findings of the three working papers.

High frequency electric machine models for the evaluation of operational impacts in integrated drives

A high frequency physical phase variable electric machine model was developed using FE analysis. The model was implemented in a machine drive environment with hardware-in-the-loop. The novelty of the proposed model is that it is derived based on the actual geometrical and other physical information of the motor, considering each individual turn in the winding. This is the first attempt to develop such a model to obtain high frequency machine parameters without resorting to expensive experimental procedures currently in use. The model was used in a dynamic simulation environment to predict inverter-motor interaction. This includes motor terminal overvoltage, current spikes, as well as switching effects. In addition, a complete drive model was developed for electromagnetic interference (EMI) analysis and evaluation. This consists of the lumped parameter models of different system components, such as cable, inverter, and motor. The lumped parameter models enable faster simulations. The results obtained were verified by experimental measurements and excellent agreements were obtained. A change in the winding arrangement and its influence on the motor high frequency behavior has also been investigated. This was shown to have a little effect on the parameter values and in the motor high frequency behavior for equal number of turns. An accurate prediction of overvoltage and EMI in the design stages of the drive system would reduce the time required for the design modifications as well as for the evaluation of EMC compliance issues. The model can be utilized in the design optimization and insulation selection for motors. Use of this procedure could prove economical, as it would help designers develop and test new motor designs for the evaluation of operational impacts in various motor drive applications.

Assessing the effectiveness of the internationalization process in Higher Education Institutions: A case study of Florida International University

The purpose of this study was to examine a Higher Education Institution’s (HEI) process of internationalization. The theoretical model developed by Van Dijk and Miejer (1997) was used to review Florida International University (FIU)’s policy, support, and implementation dimensions and determine its position on the Internationalization Cube, and assess how FIU’s international activities fit into its different organizational processes. In addition, the study sought to shed light on student and faculty attitudes toward internationalization. Qualitative and quantitative data were collected from examining organizational documents, interviews, descriptive data on FIU’s international activities using the International Dimension Index, and the Student and Faculty Survey on Internationalization. FIU’s international activities results were analyzed in relation to a panel of experts’ item relevancy index. The Likert-type survey scales’ frequencies and percentages were calculated as well as Spearman Rho correlations between the survey’s three scales and demographic and experiences variables. The study found that FIU is located on position six of a possible eight positions on the Van Dijk and Meijer Internationalization Cube with the following characteristics: Priority Policy, One-Sided Support, and Structured Implementation toward internationalization. The analysis of FIU’s results on international activities showed that FIU exhibits all the activities considered to be strong indicators of internationalization but for position seven placement special attention is needed in the areas of foreign language study, international students, study abroad, faculty movement and involvement in international projects. The survey indicated students and faculty rated the Benefits of Internationalization highly but didn’t perceive strong institutional Support for Internationalization. Faculty age and offshore programs participation; student gender, race/ethnicity and class status; and for both, study abroad and knowledge of students travel grant had significant positive correlations with student and faculty attitudes. The study concluded that an association exists between FIU’s position on the Internationalization Cube and its international activities. Recommendations for policy, implementation, and future studies were made. It was concluded that advancing FIU’s position on the Cube will require adjustments in FIU’s policy, support and implementation dimensions. Differences in student and faculty views toward internationalization should be taken into account when planning internationalization efforts.

Development of physics-based models and design optimization of power electronic conversion systems

The main objective for physics based modeling of the power converter components is to design the whole converter with respect to physical and operational constraints. Therefore, all the elements and components of the energy conversion system are modeled numerically and combined together to achieve the whole system behavioral model. Previously proposed high frequency (HF) models of power converters are based on circuit models that are only related to the parasitic inner parameters of the power devices and the connections between the components. This dissertation aims to obtain appropriate physics-based models for power conversion systems, which not only can represent the steady state behavior of the components, but also can predict their high frequency characteristics. The developed physics-based model would represent the physical device with a high level of accuracy in predicting its operating condition. The proposed physics-based model enables us to accurately develop components such as; effective EMI filters, switching algorithms and circuit topologies [7]. One of the applications of the developed modeling technique is design of new sets of topologies for high-frequency, high efficiency converters for variable speed drives. The main advantage of the modeling method, presented in this dissertation, is the practical design of an inverter for high power applications with the ability to overcome the blocking voltage limitations of available power semiconductor devices. Another advantage is selection of the best matching topology with inherent reduction of switching losses which can be utilized to improve the overall efficiency. The physics-based modeling approach, in this dissertation, makes it possible to design any power electronic conversion system to meet electromagnetic standards and design constraints. This includes physical characteristics such as; decreasing the size and weight of the package, optimized interactions with the neighboring components and higher power density. In addition, the electromagnetic behaviors and signatures can be evaluated including the study of conducted and radiated EMI interactions in addition to the design of attenuation measures and enclosures.

Development, validation and uncertainty analysis of quantitative structure and activity relationship models for Log P of disinfection by -products

Hydrophobicity as measured by Log P is an important molecular property related to toxicity and carcinogenicity. With increasing public health concerns for the effects of Disinfection By-Products (DBPs), there are considerable benefits in developing Quantitative Structure and Activity Relationship (QSAR) models capable of accurately predicting Log P. In this research, Log P values of 173 DBP compounds in 6 functional classes were used to develop QSAR models, by applying 3 molecular descriptors, namely, Energy of the Lowest Unoccupied Molecular Orbital (ELUMO), Number of Chlorine (NCl) and Number of Carbon (NC) by Multiple Linear Regression (MLR) analysis. The QSAR models developed were validated based on the Organization for Economic Co-operation and Development (OECD) principles. The model Applicability Domain (AD) and mechanistic interpretation were explored. Considering the very complex nature of DBPs, the established QSAR models performed very well with respect to goodness-of-fit, robustness and predictability. The predicted values of Log P of DBPs by the QSAR models were found to be significant with a correlation coefficient R2 from 81% to 98%. The Leverage Approach by Williams Plot was applied to detect and remove outliers, consequently increasing R 2 by approximately 2% to 13% for different DBP classes. The developed QSAR models were statistically validated for their predictive power by the Leave-One-Out (LOO) and Leave-Many-Out (LMO) cross validation methods. Finally, Monte Carlo simulation was used to assess the variations and inherent uncertainties in the QSAR models of Log P and determine the most influential parameters in connection with Log P prediction. The developed QSAR models in this dissertation will have a broad applicability domain because the research data set covered six out of eight common DBP classes, including halogenated alkane, halogenated alkene, halogenated aromatic, halogenated aldehyde, halogenated ketone, and halogenated carboxylic acid, which have been brought to the attention of regulatory agencies in recent years. Furthermore, the QSAR models are suitable to be used for prediction of similar DBP compounds within the same applicability domain. The selection and integration of various methodologies developed in this research may also benefit future research in similar fields.

The Status of Multi-Dimensional Core-Collapse Supernova Models

Models of neutrino-driven core-collapse supernova explosions have matured considerably in recent years. Explosions of low-mass progenitors can routinely be simulated in 1D, 2D, and 3D. Nucleosynthesis calculations indicate that these supernovae could be contributors of some lighter neutron-rich elements beyond iron. The explosion mechanism of more massive stars remains under investigation, although first 3D models of neutrino-driven explosions employing multi-group neutrino transport have become available. Together with earlier 2D models and more simplified 3D simulations, these have elucidated the interplay between neutrino heating and hydrodynamic instabilities in the post-shock region that is essential for shock revival. However, some physical ingredients may still need to be added/improved before simulations can robustly explain supernova explosions over a wide range of progenitors. Solutions recently suggested in the literature include uncertainties in the neutrino rates, rotation, and seed perturbations from convective shell burning. We review the implications of 3D simulations of shell burning in supernova progenitors for the ‘perturbations-aided neutrino-driven mechanism,’ whose efficacy is illustrated by the first successful multi-group neutrino hydrodynamics simulation of an 18 solar mass progenitor with 3D initial conditions. We conclude with speculations about the impact of 3D effects on the structure of massive stars through convective boundary mixing.

The Roles of Land and Orography on Precipitation and Ocean Circulation in Global Climate Models

Thesis (Ph.D.)--University of Washington, 2016-08

An experiment on the parameter uncertainty of hydrological models with different levels of complexity in a climate change context

La possibilité d’estimer l’impact du changement climatique en cours sur le comportement hydrologique des hydro-systèmes est une nécessité pour anticiper les adaptations inévitables et nécessaires que doivent envisager nos sociétés. Dans ce contexte, ce projet doctoral présente une étude sur l’évaluation de la sensibilité des projections hydrologiques futures à : (i) La non-robustesse de l’identification des paramètres des modèles hydrologiques, (ii) l’utilisation de plusieurs jeux de paramètres équifinaux et (iii) l’utilisation de différentes structures de modèles hydrologiques. Pour quantifier l’impact de la première source d’incertitude sur les sorties des modèles, quatre sous-périodes climatiquement contrastées sont tout d’abord identifiées au sein des chroniques observées. Les modèles sont calés sur chacune de ces quatre périodes et les sorties engendrées sont analysées en calage et en validation en suivant les quatre configurations du Different Splitsample Tests (Klemeš, 1986;Wilby, 2005; Seiller et al. (2012);Refsgaard et al. (2014)). Afin d’étudier la seconde source d’incertitude liée à la structure du modèle, l’équifinalité des jeux de paramètres est ensuite prise en compte en considérant pour chaque type de calage les sorties associées à des jeux de paramètres équifinaux. Enfin, pour évaluer la troisième source d’incertitude, cinq modèles hydrologiques de différents niveaux de complexité sont appliqués (GR4J, MORDOR, HSAMI, SWAT et HYDROTEL) sur le bassin versant québécois de la rivière Au Saumon. Les trois sources d’incertitude sont évaluées à la fois dans conditions climatiques observées passées et dans les conditions climatiques futures. Les résultats montrent que, en tenant compte de la méthode d’évaluation suivie dans ce doctorat, l’utilisation de différents niveaux de complexité des modèles hydrologiques est la principale source de variabilité dans les projections de débits dans des conditions climatiques futures. Ceci est suivi par le manque de robustesse de l’identification des paramètres. Les projections hydrologiques générées par un ensemble de jeux de paramètres équifinaux sont proches de celles associées au jeu de paramètres optimal. Par conséquent, plus d’efforts devraient être investis dans l’amélioration de la robustesse des modèles pour les études d’impact sur le changement climatique, notamment en développant les structures des modèles plus appropriés et en proposant des procédures de calage qui augmentent leur robustesse. Ces travaux permettent d’apporter une réponse détaillée sur notre capacité à réaliser un diagnostic des impacts des changements climatiques sur les ressources hydriques du bassin Au Saumon et de proposer une démarche méthodologique originale d’analyse pouvant être directement appliquée ou adaptée à d’autres contextes hydro-climatiques.

Development and Application of Predictive Models for Survival, Growth, and Death of Enteric Pathogens in Leafy Greens Supply Chain

Leafy greens are essential part of a healthy diet. Because of their health benefits, production and consumption of leafy greens has increased considerably in the U.S. in the last few decades. However, leafy greens are also associated with a large number of foodborne disease outbreaks in the last few years. The overall goal of this dissertation was to use the current knowledge of predictive models and available data to understand the growth, survival, and death of enteric pathogens in leafy greens at pre- and post-harvest levels. Temperature plays a major role in the growth and death of bacteria in foods. A growth-death model was developed for Salmonella and Listeria monocytogenes in leafy greens for varying temperature conditions typically encountered during supply chain. The developed growth-death models were validated using experimental dynamic time-temperature profiles available in the literature. Furthermore, these growth-death models for Salmonella and Listeria monocytogenes and a similar model for E. coli O157:H7 were used to predict the growth of these pathogens in leafy greens during transportation without temperature control. Refrigeration of leafy greens meets the purposes of increasing their shelf-life and mitigating the bacterial growth, but at the same time, storage of foods at lower temperature increases the storage cost. Nonlinear programming was used to optimize the storage temperature of leafy greens during supply chain while minimizing the storage cost and maintaining the desired levels of sensory quality and microbial safety. Most of the outbreaks associated with consumption of leafy greens contaminated with E. coli O157:H7 have occurred during July-November in the U.S. A dynamic system model consisting of subsystems and inputs (soil, irrigation, cattle, wildlife, and rainfall) simulating a farm in a major leafy greens producing area in California was developed. The model was simulated incorporating the events of planting, irrigation, harvesting, ground preparation for the new crop, contamination of soil and plants, and survival of E. coli O157:H7. The predictions of this system model are in agreement with the seasonality of outbreaks. This dissertation utilized the growth, survival, and death models of enteric pathogens in leafy greens during production and supply chain.

An analysis of the effects of preferential trade policies through the estimation of quantitative models: the case of Portugal.

Doutoramento em Economia.

Changing family models in Spain: the impact of the sociodemographic factors

Abstract During the last few decades, there has been an increasing international recognition of the studies related to the analysis of the family models change, the focus being the determinants of the female employment and the problems related to the work family balance (Lewis, 2001; Petit & Hook, 2005Saraceno, Crompton & Lyonette, 20062008; Pfau-Effinger, 2012). The majority of these studies have been focused on the analysis of the work-family balance problems as well as the effectiveness of the family and gender policies in order to encourage female employment (Korpi et al., 2013). In Spain, special attention has been given to the family policies implemented, the employability of women and on the role of the father in the family (Flaquer et al., 2015; Meil, 2015); however, there has been far less emphasis on the analysis of the family cultural models (González and Jurado, 2012; Crespi and Moreno, 2016). The purpose of this paper is to present some of the first results on the influence of the socio-demographic factors on the expectations and attitudes about the family models. This study offers an analytical reflection upon the foundation of the determinants of the family ambivalence in Spain from the cultural and the institutional dimension. This study shows the Spanish family models of preferences following the Pfau-Effinger (2004) classification of the famiy living arrangements. The reason for this study is twofold; on the one hand, there is confirmed the scarcity of studies that have focused their attention on this objective in Spain; on the other hand, the studies carried out in the international context have confirmed the analytical effectiveness of researching on the attitude and value changes to explain the meaning and trends of the family changes. There is also presented some preliminary results that have been obtained from the multinomial analysis related to the influence of the socio-demographic factors on the family model chosen by the individuals in Spain (father and mother working full time; mother part-time father full-time; mother not at work father full-time; mother and father part-time). 3 The database used has been the International Social Survey Programme: Family and Changing Gender Roles IV- ISSP 2012-. Spain is the only country of South Europe that has participated in the survey. For this reason it has been considered as a representative case study.

Development of Physics-based Models and Design Optimization of Power Electronic Conversion Systems

The main objective for physics based modeling of the power converter components is to design the whole converter with respect to physical and operational constraints. Therefore, all the elements and components of the energy conversion system are modeled numerically and combined together to achieve the whole system behavioral model. Previously proposed high frequency (HF) models of power converters are based on circuit models that are only related to the parasitic inner parameters of the power devices and the connections between the components. This dissertation aims to obtain appropriate physics-based models for power conversion systems, which not only can represent the steady state behavior of the components, but also can predict their high frequency characteristics. The developed physics-based model would represent the physical device with a high level of accuracy in predicting its operating condition. The proposed physics-based model enables us to accurately develop components such as; effective EMI filters, switching algorithms and circuit topologies [7]. One of the applications of the developed modeling technique is design of new sets of topologies for high-frequency, high efficiency converters for variable speed drives. The main advantage of the modeling method, presented in this dissertation, is the practical design of an inverter for high power applications with the ability to overcome the blocking voltage limitations of available power semiconductor devices. Another advantage is selection of the best matching topology with inherent reduction of switching losses which can be utilized to improve the overall efficiency. The physics-based modeling approach, in this dissertation, makes it possible to design any power electronic conversion system to meet electromagnetic standards and design constraints. This includes physical characteristics such as; decreasing the size and weight of the package, optimized interactions with the neighboring components and higher power density. In addition, the electromagnetic behaviors and signatures can be evaluated including the study of conducted and radiated EMI interactions in addition to the design of attenuation measures and enclosures.

Internationalization process of TUBOFURO

The central objective of this case study was to formulate the strategy of internationalization of Tubofuro®, discriminating relevant points from its design to its implementation. This is a company located in Leiria, Ortigosa parish, which operates, among others, in the Portuguese PVC pipes industry for which currently the domestic market is clearly insufficient, given the oversupply compared to demand. Being Tubofuro® an exporting company since 2004, the work here developed specifically intended to increase sales to the foreign market, with this representing 45% of total company's business in 2018 increasing of the number of markets through new partners to enable the positioning of Tubofuro® among the main players in each market, particularly in South American markets, North African and European. To achieve the above objectives presented a case study was applied, centred on Tubofuro® company, target of the internationalization strategy. The search carried out for the formulation of the strategy has been supported on a thorough analysis of the external environment and internal characteristics of the company, for which were crossed different types of data, quantitative, qualitative, secondary data and primary data. From this work resulted the development of internationalization and international marketing plan for the next three years, whose objectives are based on entrance and consequent growth in new markets, including the market Chilean, Peruvian, Mexican, Argentine, Algerian and German, as well growth in the presence and turnover in the markets for which Tubofuro® already exports regularly, for example Spain, France, Tunisia and Morocco. Based on the production capacity of Tubofuro® company, which will not suffer any kind of investment for incrementing but only to update, it is expected that the appropriate response capacity for the company is 8 regular markets, and could eventually arise sporadic exports to other markets not interfering with the normal production capacity of the company. The suggestion of the presented markets resulted from the study of the final price based on the one that local customers purchase a product equal or similar to Tubofuro® and the number of potential existing customers in each market. The internationalization model known as Uppsala Model corresponds to the strategy adopted by the company to its internationalization process, taking into account the philosophy of senior management and the risk aversion of them. The sales team Tubofuro® demand for each market, export a full container registering customer feedback, including quality and flow capacity in the market in order to seek a partnership agreement with a local distributor, which allows the Tubofuro® go to step two above mentioned model. The partnership agreement is based on mutual commitment to technical cooperation and trade between the Tubofuro® and partner, in order to increase the performance capacity among local customers. Only if the market presents a greater demand to our supply capacity and be justified by cost / benefit ratio, the entry into this market through a joint venture or subsidiary is that the decision will be taken. Although this is a case study, which means that is adjusted to the concrete case Tubofuro® preventing generalization of findings, we believe that this work can be a useful example for other companies in the internationalization process or the methodology adopted in formulating strategy or the outputs and conclusions drawn.