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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Competencia externa potencial en la industria argentina

Winkler, Hernán Jorge January 2006 (has links) (PDF)
El proceso de apertura comercial experimentado por Argentina en los años 90 sometió a la industria por primera vez en mucho tiempo a la competencia externa. Este trabajo investiga en qué medida la competencia externa potencial actuó como un limitante del poder de mercado de la industria local. Utilizando modelos dinámicos para datos en panel se demostró que dicha competencia fue significativa durante el período 1995-2001. En particular, algunos de los modelos estimados sugieren que aquellas industrias menos concentradas, con menor protección arancelaria, con economías de escala más reducidas, no vinculadas directamente a la actividad agropecuaria o que producen productos menos diferenciados son las que enfrentaron una competencia potencial externa significativa. / The process of trade liberalization experienced by Argentina in the 90s subjected domestic industries to foreign competition for the first time in many years. This paper studies to what extent potential foreign competition was a limiting factor of domestic market power. Using dynamic panel data models, this paper shows that such competition was significant between 1995 and 2001. Specifically, some of the models suggest that those industries not directly linked to agricultural activities, with a low degree of concentration, with low tariff barriers, with a low degree of economies of scale and whose output has a low degree of differentiation are the ones that experienced significant potential foreign competition. / Una versión de este trabajo obtuvo el premio "Elías Salama" otorgado en las X Jornadas de Economía Monetaria e Internacional, organizadas por el Departamento de Economía de la Universidad Nacional de La Plata.
52

Some problems in the theory & application of graphical models

Roddam, Andrew Wilfred January 1999 (has links)
A graphical model is simply a representation of the results of an analysis of relationships between sets of variables. It can include the study of the dependence of one variable, or a set of variables on another variable or sets of variables, and can be extended to include variables which could be considered as intermediate to the others. This leads to the concept of representing these chains of relationships by means of a graph; where variables are represented by vertices, and relationships between the variables are represented by edges. These edges can be either directed or undirected, depending upon the type of relationship being represented. The thesis investigates a number of outstanding problems in the area of statistical modelling, with particular emphasis on representing the results in terms of a graph. The thesis will study models for multivariate discrete data and in the case of binary responses, some theoretical results are given on the relationship between two common models. In the more general setting of multivariate discrete responses, a general class of models is studied and an approximation to the maximum likelihood estimates in these models is proposed. This thesis also addresses the problem of measurement errors. An investigation into the effect that measurement error has on sample size calculations is given with respect to a general measurement error specification in both linear and binary regression models. Finally, the thesis presents, in terms of a graphical model, a re-analysis of a set of childhood growth data, collected in South Wales during the 1970s. Within this analysis, a new technique is proposed that allows the calculation of derived variables under the assumption that the joint relationships between the variables are constant at each of the time points.
53

Firm ownership and financial structure in less developed economies : empirical evidence from three sub-Saharan economies

Komakech, Samuel January 2018 (has links)
This thesis comprehensively examines financial structure choices of firms in three emerging economies of the East African region. It highlights the lack of research in this area and empirically examines three panel data models of financial structure (ownership, firm-specific factorsâ and firm performance models, whilst incorporating the influence of macroeconomic factors) using panel data estimation techniques, including the method of moments framework. It estimates these models using panel data from 47 listed firms; and then data from 20 private firms. The original and significant contributions to knowledge of my thesis are as follows: it provides novel insights into the relation between ownership structure and firm financial structure; it provides new understanding of the relation between firm-specific factors and financial structure of quoted and private firms in emerging economies (an area where research has been lacking); it provides new understanding and additional evidence with respect to the effect of ownership structure on the performance of firms in the East African region; it incorporates the influence of macroeconomic and institutional factors on financial structure choices; and it proposes frameworks for reviewing knowledge of financial structure choices, which can be used for further scholarly work on financial structure of firms in emerging economies. The findings of this research have implications for a possibility of a new theoretical framework for researching financial structure choice of firms in emerging economies; for policy makers to design deliberate policies that enhance access to finance for firms operating in an emerging economy; and for policy makers to regulate institutions (banking sector and capital market) as they develop to ensure equitable access (particularly for the private firms) to finance by all firms operating within the economy. Taken together, the results have implication for future scholarship in that they provide clearer and useful insights on ownership structure, financial structure choices and performance of both quoted and private firms in emerging economies; and the methods used are highly replicable and can be replicated in future studies of financial structure choices of firms in emerging economies. It has also invoked further questions that require answers.
54

Quantitative models of establishments location choices : spatial effects and strategic interactions / Modèles quantitatifs de choix de localisation des établissements : effets spatiaux et interactions stratégiques

Buczkowska, Sabina 28 March 2017 (has links)
Dans un contexte de carence méthodologique, cette thèse vise à apporter un nouveau souffle aux modèles de choix de localisation jusqu’ici incapables d’appréhender de manière réaliste la complexité des processus décisionnels des établissements tels que leurs choix de localisation optimale. Les modèles de choix de localisation utilisent des données géoréférencées, pour lesquelles les ensembles de choix ont une composante spatiale explicite. Il est donc essentiel de comprendre comment représenter l’aspect spatial dans les modèles de choix de localisation. La décision finale d’un établissement semble être liée au paysage économique environnant. La quantification du lien entre les observations voisines implique une prise de décision sur la spécification de la matrice spatiale. Pourtant, la grande majorité des chercheurs appliquent la métrique euclidienne sans considérer des hypothèses sous-jacentes et ses alternatives. Cette démarche a été initialement proposée en raison de données et de puissance informatique limitées plutôt que de son universalité. Dans les régions comme la région parisienne, oû la congestion ainsi que les problèmes de barrières physiques non traversables apparaissent clairement, les distances purement basées sur la topographie peuvent ne pas être les plus appropriées pour l’étude de la localisation intra-urbaine. Il est possible d’acquérir des connaissances en reconsidérant et en mesurant la distance en fonction du problème analysé. Plutôt que d’enfermer les chercheurs dans une structure restrictive de la matrice de pondération, cette thèse propose une approche souple pour identifier la métrique de distance la plus susceptible de prendre en compte correctement les marchés voisins selon le secteur considéré. En plus de la distance euclidienne standard, six autres mesures sont testées : les temps de déplacement en voiture (pour les périodes de pointe et hors pointe) et en transport en commun, ainsi que les distances de réseau correspondantes.Par ailleurs, les décisions d’un établissement particulier sont interdépendantes des choix d’autres acteurs, ce qui rend les choix de localisation particulièrement intéressants et difficiles à analyser. Ces problèmes épineux posés par l’interdépendance des décisions ne peuvent généralement être négligés sans altérer l’authenticité du modèle de décision d’établissement. Les approches classiques de la sélection de localisation échouent en ne fournissant qu’un ensemble d’étapes systématiques pour la résolution de problèmes sans tenir compte des interactions stratégiques entre les établissements sur le marché. L’un des objectifs de la présente thèse est d’explorer comment adapter correctement les modèles de choix de localisation pour étudier les choix discrets d’établissement lorsqu’ils sont interdépendants.En outre, une entreprise peut ouvrir un certain nombre d’unités et servir le marché à partir de plusieurs localisations. Encore une fois, la théorie et les méthodes traditionnelles peuvent ne pas convenir aux situations dans lesquelles les établissements individuels, au lieu de se situer indépendamment les uns des autres, forment une grande organisation, telle qu’une chaîne confrontée à une concurrence féroce d’autres chaînes. Le modèle prend en compte non seulement les interactions intra-chaînes mais aussi inter-chaînes. Aussi, la nécessité d’indiquer une nette différence entre la population de jour et de nuit a été soulignée. La demande est représentée par les flux de piétons et de voitures, la foule de clients potentiels passant par les centres commerciaux, les stations de trains et de métros, les aéroports et les sites touristiques. L’Enquête Globale Transport 2010 (EGT 2010), entre autres, est utile pour atteindre cet objectif. / This thesis is breathing new life into the location choice models of establishments. The need for methodological advances in order to more realistically model the complexity of establishment decision-making processes, such as their optimal location choices, is the key motivation of this thesis. First, location choice models use geo-referenced data, for which choice sets have an explicit spatial component. It is thus critical to understand how to represent spatial aspect in location choice models. The final decision of an establishment seems to be related to the surrounding economic landscape. When accounting for the linkage between neighboring observations, the decision on the spatial weight matrix specification must be made. Yet, researchers overwhelmingly apply the Euclidean metric without realizing its underlying assumptions and its alternatives. This representation has been originally proposed due to scarce data and low computing power, rather than because of its universality. In areas, such as the Paris region, where high congestion or uncrossable physical barriers problems clearly arise, distances purely based on topography may not be the most appropriate for the study of intra-urban location. There are insights to be gained by mindfully reconsidering and measuring distance depending on a problem being analyzed. Rather than locking researchers into a restrictive structure of the weight matrix, this thesis proposes a flexible approach to intimate which distance metric is more likely to correctly account for the nearby markets depending on the sector considered. In addition to the standard Euclidean distance, six alternative metrics are tested: travel times by car (for the peak and off-peak periods) and by public transit, and the corresponding network distances. Second, what makes these location choices particularly interesting and challenging to analyze is that decisions of a particular establishment are interrelated with choices of other players.These thorny problems posed by the interdependence of decisions generally cannot be assumed away, without altering the authenticity of the model of establishment decision making. The conventional approaches to location selection fail by providing only a set of systematic steps for problem-solving without considering strategic interactions between the establishments in the market. One of the goals of the present thesis is to explore how to correctly adapt location choice models to study establishment discrete choices when they are interrelated.Finally, a firm can open a number of units and serve the market from multiple locations. Once again, traditional theory and methods may not be suitable to situations wherein individual establishments, instead of locating independently from each other, form a large orgnization, such as a chain facing a fierce competition from other chains. There is a necessity to incorporate interactions between units within the same and competing firms. In addition, the need to state a clear difference between the daytime and nighttime population has been emphasized. Demand is represented by pedestrian and car flows, the crowd of potential clients passing through the commercial centers, train and subways stations, airports, and highly touristic sites. The Global Survey of Transport (EGT 2010), among others, is of service to reach this objective. More realistically designed location choice models accounting for spatial spillovers, strategic interaction, and with a more appropriate definition of distance and demand can become a powerful and flexible tool to assist in finding a befitting site. An appropriately chosen location in turn can make an implicative difference for the newly-created business. The contents of this thesis provide some useful recommendations for transport analysts, city planners, plan developers, business owners, and shopping center investors.
55

Ensaio em economia da saúde: análise da demanda no mercado de saúde suplementar utilizando um modelo econométrico de dados de contagem

Heck, Joaquim 31 August 2012 (has links)
Submitted by Joaquim Heck (jheck@embrioconsult.com.br) on 2012-09-26T17:54:24Z No. of bitstreams: 1 PDF_MPFE_2010_Dissertacao_Joaquim_Heck_2012_08_31.pdf: 1254577 bytes, checksum: 286251ccfbb405513a08d5b0d097a172 (MD5) / Approved for entry into archive by Suzinei Teles Garcia Garcia (suzinei.garcia@fgv.br) on 2012-09-26T18:01:33Z (GMT) No. of bitstreams: 1 PDF_MPFE_2010_Dissertacao_Joaquim_Heck_2012_08_31.pdf: 1254577 bytes, checksum: 286251ccfbb405513a08d5b0d097a172 (MD5) / Made available in DSpace on 2012-09-26T18:09:46Z (GMT). No. of bitstreams: 1 PDF_MPFE_2010_Dissertacao_Joaquim_Heck_2012_08_31.pdf: 1254577 bytes, checksum: 286251ccfbb405513a08d5b0d097a172 (MD5) Previous issue date: 2012-08-31 / This thesis discusses aspects of the demand for healthcare in the Brazilian private health sector. We use econometric analysis of count data models to establish which monetary and non-monetary parameters may influence the demand of healthcare. Finally, we verify if there is any informational asymmetry effect such as moral hazard in the determination of the demand for a case-study involving medical speciality visits. / Este ensaio apresenta um estudo sobre a demanda por serviço de saúde no mercado de saúde suplementar utilizando, através de uma análise econométrica, modelos de regressão de dados de contagem para verificar os fatores monetários e não monetários que podem influenciar a quantidade demandada por este serviço, e determinar se há risco moral na determinação desta demanda, no caso de um modelo de visitas médicas de especialidade.
56

On two Random Models in Data Analysis

James, David 12 January 2017 (has links)
No description available.
57

An Empirical Comparison of Static Count Panel Data Models: the Case of Vehicle Fires in Stockholm County

Pihl, Svante, Olivetti, Leonardo January 2020 (has links)
In this paper we study the occurrences of outdoor vehicle fires recorded by the Swedish Civil Contingencies Agency (MSB) for the period 1998-2019, and build static panel data models to predict future occurrences of fire in Stockholm County. Through comparing the performance of different models, we look at the effect of different distributional assumptions for the dependent variable on predictive performance. Our study concludes that treating the dependent variable as continuous does not hamper performance, with the exception of models meant to predict more uncommon occurrences of fire. Furthermore, we find that assuming that the dependent variable follows a Negative Binomial Distribution, rather than a Poisson Distribution, does not lead to substantial gains in performance, even in cases of overdispersion. Finally, we notice a slight increase in the number of vehicle fires shown in the data, and reflect on whether this could be related to the increased population size.
58

Data Model Canvas für die IT-Systemübergreifende Integration von Datenmodellen zur Unterstützung von Datenanalyse-Anwendungen im Produktlebenszyklus

Eickhoff, Thomas, Eiden, Andreas, Gries, Jonas, Göbel, Jens C. 06 September 2021 (has links)
Der Data Model Canvas (DMC) unterstützt methodisch und informationstechnisch den Aufbau der für ein durchgängiges und interdisziplinäres Engineering benötigten fachlichen Datengrundlage und deren Abbildung in den betreffenden IT-Systemen. Basierend auf konkreten Analyse-Szenarien erfolgt eine Modellierung der erforderlichen Datenvernetzung, die wiederum die explizit benötigten Datenquellen umfasst. Im Mittelpunkt dieses Ansatzes steht die Entwicklung eines fachlichen Verständnisses über die zur Analyse notwendigen roduktdaten. Unterstützt wird der Ansatz durch ein Softwaretool zur Erstellung der benötigten Datenmodelle.
59

Kletba přírodních zdrojů a stínová ekonomika: empirická evidence / Natural Resource Curse and Shadow Economy: Emprical Evidence

Chen, Anna January 2021 (has links)
The study aims to investigate the impact of natural resource wealth on the shadow economy. The theoretical section provides the basis of understanding the nature of two phenomena and discusses the possible transmission channels through which natural resources might influence the shadow economy. Consequently, the key determinants of the shadow economy are examined by static and dynamic models. Natural resource abundance is proxied by natural resource rents. We employ a panel data set for 109 countries for the period from 1996 to 2006. The results reveal that resource wealth is associated with the decrease of the shadow economy. This result is robust for different resource types (durable and non-durable), and the effect is more profound for countries with a low income level. JEL Classification C33, E26, O13 Keywords natural resources, shadow economy, dynamic panel data models, system GMM estimator Title Natural Resource Curse and Shadow Economy: Empirical Evidence
60

AI-Based Transport Mode Recognition for Transportation Planning Utilizing Smartphone Sensor Data From Crowdsensing Campaigns

Grubitzsch, Philipp, Werner, Elias, Matusek, Daniel, Stojanov, Viktor, Hähnel, Markus 11 May 2023 (has links)
Utilizing smartphone sensor data from crowdsen-sing (CS) campaigns for transportation planning (TP) requires highly reliable transport mode recognition. To address this, we present our RNN-based AI model MovDeep, which works on GPS, accelerometer, magnetometer and gyroscope data. It was trained on 92 hours of labeled data. MovDeep predicts six transportation modes (TM) on one second time windows. A novel postprocessing further improves the prediction results. We present a validation methodology (VM), which simulates unknown context, to get a more realistic estimation of the real-world performance (RWP). We explain why existing work shows overestimated prediction qualities, when they would be used on CS data and why their results are not comparable with each other. With the introduced VM, MovDeep still achieves 99.3 % F1 -Score on six TM. We confirm the very good RWP for our model on unknown context with the Sussex-Huawei Locomotion data set. For future model comparison, both publicly available data sets can be used with our VM. In the end, we compare MovDeep to a deterministic approach as a baseline for an average performing model (82 - 88 % RWP Recall) on a CS data set of 540 k tracks, to show the significant negative impact of even small prediction errors on TP.

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