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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.
261

Forecast Comparison of Models Based on SARIMA and the Kalman Filter for Inflation

Nikolaisen Sävås, Fredrik January 2013 (has links)
Inflation is one of the most important macroeconomic variables. It is vital that policy makers receive accurate forecasts of inflation so that they can adjust their monetary policy to attain stability in the economy which has been shown to lead to economic growth. The purpose of this study is to model inflation and evaluate if applying the Kalman filter to SARIMA models lead to higher forecast accuracy compared to just using the SARIMA model. The Box-Jenkins approach to SARIMA modelling is used to obtain well-fitted SARIMA models and then to use a subset of observations to estimate a SARIMA model on which the Kalman filter is applied for the rest of the observations. These models are identified and then estimated with the use of monthly inflation for Luxembourg, Mexico, Portugal and Switzerland with the target to use them for forecasting. The accuracy of the forecasts are then evaluated with the error measures mean squared error (MSE), mean average deviation (MAD), mean average percentage error (MAPE) and the statistic Theil's U. For all countries these measures indicate that the Kalman filtered model yield more accurate forecasts. The significance of these differences are then evaluated with the Diebold-Mariano test for which only the difference in forecast accuracy of Swiss inflation is proven significant. Thus, applying the Kalman filter to SARIMA models with the target to obtain forecasts of monthly inflation seem to lead to higher or at least not lower predictive accuracy for the monthly inflation of these countries.
262

Evaluating forecast accuracy for Error Correction constraints and Intercept Correction

Eidestedt, Richard, Ekberg, Stefan January 2013 (has links)
This paper examines the forecast accuracy of an unrestricted Vector Autoregressive (VAR) model for GDP, relative to a comparable Vector Error Correction (VEC) model that recognizes that the data is characterized by co-integration. In addition, an alternative forecast method, Intercept Correction (IC), is considered for further comparison. Recursive out-of-sample forecasts are generated for both models and forecast techniques. The generated forecasts for each model are objectively evaluated by a selection of evaluation measures and equal accuracy tests. The result shows that the VEC models consistently outperform the VAR models. Further, IC enhances the forecast accuracy when applied to the VEC model, while there is no such indication when applied to the VAR model. For certain forecast horizons there is a significant difference in forecast ability between the VEC IC model compared to the VAR model.
263

Bulk electric system reliability evaluation incorporating wind power and demand side management

Huang, Dange 25 February 2010
Electric power systems are experiencing dramatic changes with respect to structure, operation and regulation and are facing increasing pressure due to environmental and societal constraints. Bulk electric system reliability is an important consideration in power system planning, design and operation particularly in the new competitive environment. A wide range of methods have been developed to perform bulk electric system reliability evaluation. Theoretically, sequential Monte Carlo simulation can include all aspects and contingencies in a power system and can be used to produce an informative set of reliability indices. It has become a practical and viable tool for large system reliability assessment technique due to the development of computing power and is used in the studies described in this thesis. The well-being approach used in this research provides the opportunity to integrate an accepted deterministic criterion into a probabilistic framework. This research work includes the investigation of important factors that impact bulk electric system adequacy evaluation and security constrained adequacy assessment using the well-being analysis framework.<p> Load forecast uncertainty is an important consideration in an electrical power system. This research includes load forecast uncertainty considerations in bulk electric system reliability assessment and the effects on system, load point and well-being indices and reliability index probability distributions are examined. There has been increasing worldwide interest in the utilization of wind power as a renewable energy source over the last two decades due to enhanced public awareness of the environment. Increasing penetration of wind power has significant impacts on power system reliability, and security analyses become more uncertain due to the unpredictable nature of wind power. The effects of wind power additions in generating and bulk electric system reliability assessment considering site wind speed correlations and the interactive effects of wind power and load forecast uncertainty on system reliability are examined. The concept of the security cost associated with operating in the marginal state in the well-being framework is incorporated in the economic analyses associated with system expansion planning including wind power and load forecast uncertainty. Overall reliability cost/worth analyses including security cost concepts are applied to select an optimal wind power injection strategy in a bulk electric system. The effects of the various demand side management measures on system reliability are illustrated using the system, load point, and well-being indices, and the reliability index probability distributions. The reliability effects of demand side management procedures in a bulk electric system including wind power and load forecast uncertainty considerations are also investigated. The system reliability effects due to specific demand side management programs are quantified and examined in terms of their reliability benefits.
264

Family physician work force projections in Saskatchewan

Lam, Kit Ling (Doris) 28 November 2008
This thesis applies the econometric projection approach to forecast the numbers of general practitioners (GPs) in Saskatchewan for the next 15 years at both provincial and the Regional Health Authorities (RHAs) levels. The projection results will provide the estimated level of GPs up to 2021 for policy makers to adjust their decision on health professionals planning.<p> Three hypothesized scenarios, which include the changes in population proportion, average income for GPs and a combination of both, are used for projections based on the regression results. The projections suggest a 4.34% expected annual increase of GPs if the proportions of children and seniors increase or decrease according to prediction for the next 15 years for Saskatchewan. At the RHAs level, 4.5% to 10.7% expected annual rate of increase for numbers of GPs is projected for the northern RHAs and Saskatoon RHA, while the expected increase for other urban RHAs will experience less than 1.5% increases.<p> The predicted changes in average income for GPs show insignificant effect for the expected changes in numbers of GPs. However, the second and third scenarios are not extended to the RHAs level due to lack of information, which requires additional data for both Saskatchewan physicians and population for further projection analysis.
265

Essays on Lifetime Uncertainty: Models, Applications, and Economic Implications

Zhu, Nan 07 August 2012 (has links)
My doctoral thesis “Essays on Lifetime Uncertainty: Models, Applications, and Economic Implications” addresses economic and mathematical aspects pertaining to uncertainties in human lifetimes. More precisely, I commence my research related to life insurance markets in a methodological direction by considering the question of how to forecast aggregate human mortality when risks in the resulting projections is important. I then rely on the developed method to study relevant applied actuarial problems. In a second strand of research, I consider the uncertainty in individual lifetimes and its influence on secondary life insurance market transactions. Longevity risk is becoming increasingly crucial to recognize, model, and monitor for life insurers, pension plans, annuity providers, as well as governments and individuals. One key aspect to managing this risk is correctly forecasting future mortality improvements, and this topic has attracted much attention from academics as well as from practitioners. However, in the existing literature, little attention has been paid to accurately modeling the uncertainties associated with the obtained forecasts, albeit having appropriate estimates for the risk in mortality projections, i.e. identifying the transiency of different random sources affecting the projections, is important for many applications. My first essay “Coherent Modeling of the Risk in Mortality Projections: A Semi-Parametric Approach” deals with stochastically forecasting mortality. In contrast to previous approaches, I present the first data-driven method that focuses attention on uncertainties in mortality projections rather than uncertainties in realized mortality rates. Specifically, I analyze time series of mortality forecasts generated from arbitrary but fixed forecasting methodologies and historic mortality data sets. Building on the financial literature on term structure modeling, I adopt a semi-parametric representation that encompasses all models with transitions parameterized by a Normal distributed random vector to identify and estimate suitable specifications. I find that one to two random factors appear sufficient to capture most of the variation within all of our data sets. Moreover, I observe similar systematic shapes for their volatility components, despite stemming from different forecasting methods and/or different mortality data sets. I further propose and estimate a model variant that guarantees a non-negative process of the spot force of mortality. Hence, the resulting forward mortality factor models present parsimonious and tractable alternatives to the popular methods in situations where the appraisal of risks within medium or long-term mortality projections plays a dominant role. Relying on a simple version of the derived forward mortality factor models, I take a closer look at their applications in the actuarial context in the second essay “Applications of Forward Mortality Factor Models in Life Insurance Practice. In the first application, I derive the Economic Capital for a stylized UK life insurance company offering traditional product lines. My numerical results illustrate that (systematic) mortality risk plays an important role for a life insurer's solvency. In the second application, I discuss the valuation of different common mortality-contingent embedded options within life insurance contracts. Specifically, I present a closed-form valuation formula for Guaranteed Annuity Options within traditional endowment policies, and I demonstrate how to derive the fair option fee for a Guaranteed Minimum Income Benefit within a Variable Annuity Contract based on Monte Carlo simulations. Overall my results exhibit the advantages of forward mortality factor models in terms of their simplicity and compatibility with classical life contingencies theory. The second major part of my doctoral thesis concerns the so-called life settlement market, i.e. the secondary market for life insurance policies. Evolving from so-called “viatical settlements” popular in the late 1980s that targeted severely ill life insurance policyholders, life settlements generally involve senior insureds with below average life expectancies. Within such a transaction, both the liability of future contingent premiums and the benefits of a life insurance contract are transferred from the policyholder to a life settlement company, which may further securitize a bundle of these contracts in the capital market. One interesting and puzzling observation is that although life settlements are advertised as a high-return investment with a low “Beta”, the actual market systematically underperformed relative to expectations. While the common explanation in the literature for this gap between anticipated and realized returns falls on the allegedly meager quality of the underlying life expectancy estimates, my third essay “Coherent Pricing of Life Settlements under Asymmetric Information” proposes a different viewpoint: The discrepancy may be explained by adverse selection. Specifically, by assuming information with respect to policyholders’ health states is asymmetric, my model shows that a discrepancy naturally arises in a competitive market when the decision to settle is taken into account for pricing the life settlement transaction, since the life settlement company needs to shift its pricing schedule in order to balance expected profits. I derive practically applicable pricing formulas that account for the policyholder’s decision to settle, and my numerical results reconfirm that---depending on the parameter choices---the impact of asymmetric information on pricing may be considerable. Hence, my results reveal a new angle on the financial analysis of life settlements due to asymmetric information. Hence, all in all, my thesis includes two distinct research strands that both analyze certain economic risks associated with the uncertainty of individuals’ lifetimes---the first at the aggregate level and the second at the individual level. My work contributes to the literature by providing both new insights about how to incorporate lifetime uncertainty into economic models, and new insights about what repercussions---that are in part rather unexpected---this risk factor may have.
266

Future North Sea oil production and its implications for Swedish oil supply regarding the transport sector : -A study on energy security and sustainability of future strategic resources

Sällh, David January 2012 (has links)
Historically, it has been negative to be dependent on only one resource, in the current situation this resource represents oil. The oil dependence is primarily in the transport sector. From a Swedish perspective oil is an energy resource mainly used in the transport sector. Much of the oil that Sweden imports has its origin in the North Sea. The oil production in the North Sea has however begun to decline, which highlights that oil is a finite resource. This also means that Sweden has to start importing oil from other countries, which may affect the Swedish energy security as these countries may be geographical further away and also be more political instable. It also implies that a transition from oil to renewable fuel within the transport sector is essential. The aim of this thesis is to study how Swedish energy security is affected by the oil production volumes in The North Sea. The thesis is divided into three parts. The first part consists of updating historical data from recent analyses on North Sea oil production (i.e. Höök and Aleklett, 2008 and Höök et al., 2009a), and also create updated forecasts of future oil production for both Denmark and Norway. The second part investigates how production declines in the North Sea affect the Swedish oil imports. The final section examines how a shift to renewable fuels within the transport sector is possible, with a focus on natural resources. Finally some recommendations are presented on how Sweden could increase their energy security regarding the transport sector by introducing renewable fuels.
267

Family physician work force projections in Saskatchewan

Lam, Kit Ling (Doris) 28 November 2008 (has links)
This thesis applies the econometric projection approach to forecast the numbers of general practitioners (GPs) in Saskatchewan for the next 15 years at both provincial and the Regional Health Authorities (RHAs) levels. The projection results will provide the estimated level of GPs up to 2021 for policy makers to adjust their decision on health professionals planning.<p> Three hypothesized scenarios, which include the changes in population proportion, average income for GPs and a combination of both, are used for projections based on the regression results. The projections suggest a 4.34% expected annual increase of GPs if the proportions of children and seniors increase or decrease according to prediction for the next 15 years for Saskatchewan. At the RHAs level, 4.5% to 10.7% expected annual rate of increase for numbers of GPs is projected for the northern RHAs and Saskatoon RHA, while the expected increase for other urban RHAs will experience less than 1.5% increases.<p> The predicted changes in average income for GPs show insignificant effect for the expected changes in numbers of GPs. However, the second and third scenarios are not extended to the RHAs level due to lack of information, which requires additional data for both Saskatchewan physicians and population for further projection analysis.
268

Bulk electric system reliability evaluation incorporating wind power and demand side management

Huang, Dange 25 February 2010 (has links)
Electric power systems are experiencing dramatic changes with respect to structure, operation and regulation and are facing increasing pressure due to environmental and societal constraints. Bulk electric system reliability is an important consideration in power system planning, design and operation particularly in the new competitive environment. A wide range of methods have been developed to perform bulk electric system reliability evaluation. Theoretically, sequential Monte Carlo simulation can include all aspects and contingencies in a power system and can be used to produce an informative set of reliability indices. It has become a practical and viable tool for large system reliability assessment technique due to the development of computing power and is used in the studies described in this thesis. The well-being approach used in this research provides the opportunity to integrate an accepted deterministic criterion into a probabilistic framework. This research work includes the investigation of important factors that impact bulk electric system adequacy evaluation and security constrained adequacy assessment using the well-being analysis framework.<p> Load forecast uncertainty is an important consideration in an electrical power system. This research includes load forecast uncertainty considerations in bulk electric system reliability assessment and the effects on system, load point and well-being indices and reliability index probability distributions are examined. There has been increasing worldwide interest in the utilization of wind power as a renewable energy source over the last two decades due to enhanced public awareness of the environment. Increasing penetration of wind power has significant impacts on power system reliability, and security analyses become more uncertain due to the unpredictable nature of wind power. The effects of wind power additions in generating and bulk electric system reliability assessment considering site wind speed correlations and the interactive effects of wind power and load forecast uncertainty on system reliability are examined. The concept of the security cost associated with operating in the marginal state in the well-being framework is incorporated in the economic analyses associated with system expansion planning including wind power and load forecast uncertainty. Overall reliability cost/worth analyses including security cost concepts are applied to select an optimal wind power injection strategy in a bulk electric system. The effects of the various demand side management measures on system reliability are illustrated using the system, load point, and well-being indices, and the reliability index probability distributions. The reliability effects of demand side management procedures in a bulk electric system including wind power and load forecast uncertainty considerations are also investigated. The system reliability effects due to specific demand side management programs are quantified and examined in terms of their reliability benefits.
269

An Introduction to Application of Statistical Methods in Modeling the Climate Change

Mohammadipour Gishani, Azadeh January 2012 (has links)
There are many unsolved questions about the future of climate, and most of them are due to lack of knowledgeabout the complex system of atmosphere, but still there are models that produce relatively realistic projectionsof the future although there are uncertainties in the presentation of them, and that's where statistical methodscould be of help. Here a short introduction is given to the projection of future climate with GCM ensembles andthe uncertainties about them, the emerging probabilistic approach, as well as the REA (Reliability EnsembleAverage) method for measuring the reliability of the model projections. In order to have an impression of theresults of the GCM ensemble results and their uncertainties the results of the weather forecast over a time periodof one year in three dierent cities of Sweden is studied as well.
270

Post Earnings Announcement Drift in Sweden : Evidence and application of theories in Behavioural Finance

Magnusson, Fredrik January 2012 (has links)
The post earnings announcement drift is a market anomaly causing a firms cumulative abnormal returns to drift in the direction of an earnings surprise. By measuring quarterly earnings surprises using two measures. The first based upon a times series prediction and the other based upon on analyst forecast errors. This study finds evidence that the drift ex-ists in Sweden and that investor’s systematically underreacts towards positive earnings sur-prises. Further this study shows that the cumulative average abnormal returns is larger for surprises caused by analyst forecast errors. While previous studies have tried to explain the drift by taking on additional risk or illiquidity in the stocks. This study provides evidence supporting that investors limitations in weighting new information causes an underreaction, hence a drift in the stock prices.

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