Since its creation in 1998, the Implicit Association Test (IAT) has become a commonly used measure in social psychology and related fields of research. Studies of the cognitive processes involved in the IAT are necessary to establish the validity of this measure and to suggest further refinements to its use and interpretation. The current thesis used ERPs to study cognitive processes associated with the IAT. The first experiment found significant differences in P300 amplitude in the Congruent and Incongruent conditions, which were interpreted as a reflection of greater equivocation in the Incongruent condition. The second experiment tested the task-set switching account of the IAT in much greater detail by analyzing each trial type separately. In the Congruent condition, all trial types elicited the same amplitude P300. Local probability, and the consequent checking and updating of working memory, was thought to be responsible for differences between trials of the Incongruent condition that required or did not require a task switch. The final experiment examined the role of working memory in the IAT by introducing obtrusive and irrelevant auditory stimuli. The results of Experiment 3 indicated that the introduction of an obtrusive and irrelevant auditory increment deviant has little overall effect on the IAT, and a similar effect on switch and no-switch trials within the Incongruent condition. This could have been because both the Congruent and Incongruent conditions of the IAT make such extensive demands on central processing resources that few are available to allow for the switching of attention, or it is possible that the IAT does not require significant updating of working memory. The usefulness of ERPs in the study of the IAT effect is demonstrated by the current research. In particular, the finding that behavioural results were not always consistent with the ERP results demonstrates that electrophysiological measures can complement traditional behavioural measures.

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El objetivo principal de la investigación emprendida en la presente tesis doctoral es elaborar una técnica de construcción de un indicador económico compuesto o un conjunto de dichos indicadores que, correspondiendo al concepto teorético del ciclo económico (comercial), permitirán detectar y predecir los puntos de giro del ciclo económico.Como el punto de partida hemos escogido la definición del ciclo económico propuesta por Burns y Mitchell (1946). Según nuestra opinión, el analisis dinámico factorial es el método idóneo para captar los puntos de giro del ciclo económico en el sentido de Burns y Mitchell. Por un lado, tiene en cuenta los movimientos comunes de varias series macroeconómicas que bajan y suben simultaneamente durante las fases de recesiones y expansiones, respectivamente. Por otro lado, refleja las asimetrías que existen entre las dos fases cíclicas, como, por ejemplo, las tasas de crecimiento y la volatilidad distintas durante las recesiones y expansiones. Ambos rasgos estan subrayados por Burns y Mitchell como características definitivas del ciclo económico.El análisis dinámico factorial en su estado actual exige sin duda ciertas modificaciones y algunas extensiones para obtener las estimaciones insesgadas y consistentes de los indicadores económicos compuestos y para utilizar la información disponible de la mejor manera posible.Nuestra investigación está dirigida, en primer lugar, hacia los economistas prácticos que han optado por utilizar el análisis dinámico factorial para la construcción del indicador del ciclo económico tanto a nivél regional como nacional.La tesis esta compuesta por cinco capítulos donde el primer y el último capítulos son, respectivamente, la introducción y la conclusión. En ellos se exponen los objetivos del estudio y los resultados alcanzados en el curso de la investigación.En el capítulo dos describimos varios metodos de análisis de las fluctuaciones económicas que han sido propuestos durante los últimos 20 años. Por un lado, consideramos los modelos con la dinámica nolineal, concretamente el cambio de regímenes o el Markov switching. Por otro lado, examinamos los modelos lineales del análisis dinámico factorial. Al final del capítulo analizamos el modelo del factor común latente con la dinámica nolineal (con cambios de regímenes) que está construido como una combinación de estos dos metodos principales.En el capítulo tres introducimos un modelo general dinámico multifactorial con la dinámica lineal y nolineal. Este modelo permite captar la dimensión intertemporal (indicador avanzado versus indicador coincidente) de los factores comunes inobservables. Se examinan dos modelos dinámicos alternativos con un factor común inobservable avanzado y un factor común inobservable coincidente. En el primer modelo el factor común coincidente esta influido por el factor común avanzado a través del mecanismo de causalidad de Granger. Mientras que en el segundo modelo los dos factores estan relacionados via la matríz de las probabilidades de transición. Debido a que el factor avanzado contiene información sobre los cambios futuros de las fases cíclicas, ambos modelos permiten hacer predicciones de los puntos de giro del ciclo económico.En el capítulo cuatro elaboramos las técnicas sumplementarias necesarias para resolver algunos problemas de datos que son bastante frecuentes en la actividad de un economista empírico. Los dos problemas más importantes son los cambios estructurales y la falta de observaciones, particularmente cuando los datos que estan disponibles con distintas frecuencias (por ejemplo: los datos mensuales y trimestrales). Estos problemas quiebran la continuidad de la serie temporal y reducen el número de observaciones válidas para el análisis estadístico. Se demuestra que estos problemas se resuelven modificando el modelo de análisis dinámico factorial, con lo que se obtienen estimaciones más eficientes de los parametros del modelo. / The main objective of our research undertaken in this thesis is to elaborate a technique of constructing a composite economic indicator or a set of such indicators which would correspond to the theoretical concept of business cycle and reflect a phenomenon which may be interpreted as the cyclical dynamics of the economy.As a point of departure we have chosen the definition of business cycle proposed by Burns and Mitchell (1946). We believe that the most appropriate method to capture the Burns and Mitchell's cycle would be the dynamic factor analysis.The dynamic factor analysis in its current state requires undoubtedly some refinements and extensions to obtain unbiased and consistent estimates of the composite economic indicators and to use the available information in the best possible way.Our research is mostly oriented towards the practitioners who have opted for using the dynamic factor approach in the construction of the business cycle indicator both at the regional and national levels.The thesis is comprised of five chapters where the first and the last chapters are the introduction and conclusion delineating the objectives of the study and summarizing the results achieved during research.Chapter two describes various approaches to the analysis of economic fluctuations proposed during the last 20 years. On the one hand, it concentrates on models with nonlinear, namely Markov-switching, dynamics, on the other hand, it is concerned with dynamic factor models. Finally, it shows the combined techniques which unify these two principal approaches, thus, modeling common latent factor with regime-switching dynamics.In chapter three we introduce a general multifactor dynamic model with linear and regime-switching dynamics. This model allows capturing the intertemporal (leading versus coincident) dimension of the latent common factors. Two alternative multifactor dynamic models with a leading and a coincident unobserved common factors are examined: a model where the common coincident factor is Granger-caused by the common leading factor and a model where the leading relationship is translated into a set of specific restrictions imposed on the transition probabilities matrix.Chapter four concentrates on the supplementary devices which allow to overcome some data problems which are very frequent in the practitioner's life. Among the most prominent are the structural breaks and missing observations. It is shown that some of these troubles can be coped with by modifying the dynamic common factors models, which leads to more efficient estimates of the parameters of the models.

Esta tesis consiste en tres artículos de investigación independientes que analizan diferentes estrategias implementadas en los mercados con competencia imperfecta.El primer articulo presenta un modelo formal que explica algunas de las razones que determinan las empresas producir segundas marcas - productos de perfil relativamente bajo lanzados por las empresas de renombre que deciden introducir diferenciación vertical. El modelo que presentamos incluye dos versiones. En la primera, la competencia en el espacio horizontal tiene lugar entre rivales que producen bienes de calidad alta similar, con diferentes bases de consumidores potenciales. En este caso, la producción de segundas marcas por las empresas intermedias puede surgir como un equilibrio en un juego no-cooperativo. Este resultado está en concordancia con las observaciones empíricas sobre los productores de tamaño medio que producen marcas blancas para atacar al líder del mercado. En la segunda versión del modelo, la competencia horizontal viene de un rival de calidad baja. Aquí, incluso los lideres del mercado pueden producir segundas marcas para protegerse de la competencia en el segmento bajo del mercado. Esto es similar con el propósito de los "fighting brands" comentados en la literatura de management. Finalmente, incluimos un análisis de bienestar para los dos casos.El segundo articulo trata sobre si la entrada es socialmente deseable. Obtenemos resultados opuestos a los obtenidos en los estudios anteriores que apuntan a una tendencia de entrada excesiva. El supuesto crucial que lleva a estos resultados previos es la simetría entre las empresas que ya existen en el mercado y los entrantes potenciales. Nuestro papel, apoyado por las observaciones empíricas en los nuevos mercados privatizados de Europa del Este, permite a los nuevos entrantes que sean mas competitivos. En este caso, tanto para la competencia en cantidad como para la de precios, la entrada puede ser insuficiente desde el punto de vista social. Este papel propone también una herramienta original para regular la entrada.Finalmente, el objetivo del tercer capitulo de la tesis es estudiar los efectos de los costes de sustitución endógenos sobre la eficiencia económica y el bienestar de los consumidores en nuevos contextos económicos a los estudiados hasta ahora por la literatura. El principal resultado de este articulo es que los programas que premian la lealtad de los consumidores (las empresas que endogenizan los costes de sustitución) aumentan la competencia. Nosotros utilizamos un modelo de competencia monopolistica, que elimina el efecto estratégico encontrado en modelos previos de duopolio. El papel también demuestra que la forma de compromiso es irrelevante: una función lineal de descuentos es equivalente al compromiso en precios futuros. Finalmente demostramos que la presencia de costes de sustitución exógenos reduce los incentivos de las empresas de introducir costes de sustitución endógenos. / This thesis consists of three independent pieces of research analysing different strategies implemented in imperfectly competitive markets.The first article of the thesis presents a formal model that explains some of the reasons that lie behind firms' decisions to produce secondary brands. These are lower profile products that well-known brand names launch when decide to introduce vertical differentiation. Two versions of a theoretical model are provided. In the first one, competition in the horizontal space takes place between similar high-quality rivals with different potential customer bases. In this case, production of secondary brands by intermediate firms may emerge as the equilibrium of a non-cooperative game. This is in line with the empirical observations regarding medium size manufacturers that produce private labels in order to attack the brand leader. In the second version of the model, horizontal competition comes from a low-quality rival. Here, even market leaders may produce secondary brands to protect themselves from competition in the low-end of the market. This is similar to the scope of fighting brands discussed in the management literature. Finally, some welfare analysis is provided for the two cases.The second article deals with the social desirability of entry. Previous results in the literature, pointing to a tendency for excessive entry, are reversed. The crucial assumption leading to these results is the symmetry between incumbents and potential entrants. This paper, supported by empirical observations from the newly privatised markets in Eastern Europe, allows for more competitive entrants. In this case, both for quantity and price competition, entry may be insufficient. The paper also proposes an innovative intervention tool to regulate entry.Finally, the third chapter of the thesis analyses the effects of loyalty rewarding pricing schemes on market performance. Unlike previous results in the literature and against the believes of some policy analysts, the main finding of this paper is that these programs enhance competition. Strategic commitment effect, present in duopoly analysis, was crucial in determining the results of previous articles dealing with this issue. This effect is eliminated here by using a monopolistically competitive framework, which leads to a more realistic approach. The paper also shows that, the form of commitment is irrelevant, as a linear discounting rule is equivalent to committing to future prices. Finally, it is proved that the presence of exogenous switching costs reduces firm's incentives to introduce endogenous switching costs.

What objective should an entrepreneur focus on when starting a new business enterprise? Both a survival orientation and a profit one are important for the continuity of the new venture, but a survival focus is key in the hazardous early months or even years. In this thesis, I identify the conditions under which an entrepreneur should switch from a survival orientation, where the venture’s likelihood of survival is more critical, to a profit orientation where the venture’s profit instead is more critical. I accomplish this task by determining the optimal time to switch from a survival to a profit orientation based on maximizing the entrepreneur’s accumulated utility over a given time horizon. At each time period, the utility is positively associated with the amount of added value to the business venture that entrepreneur owns and manages, and the time horizon is determined by the time at which the entrepreneur’s venture exit – for instance, it is being sold. That added value contains a planned portion (e.g., due to what the entrepreneur can control) and an unplanned portion. The portion of a firm’s added value that is unplanned depends on the entrepreneur’s orientation, whereby, at any time period, the expected added value and its variation are considered to be low under a survival orientation, but they are considered to be high under a profit orientation. I use an approach from the economics literature, known as the LEN model, where the use of an exponential utility function (E), a linear relationship between the utility and random effects (L), and normality of those random effects (N) allow me to transfer the probabilistic objective function into a certainty equivalent that makes the problem tractable. The decision framework and its resulting findings suggest two environmental and two entrepreneurial characteristics that influence the existence of a time at which to switch orientation from survival to profit. Based on these characteristics, I derive sixteen scenarios and discussed some of the necessary conditions for the existence of a switching time. I find that it is not straightforward to determine whether the orientation switch should be delayed or expedited as business environments (or entrepreneurial types) are compared. I thus further develop my analysis by adding more structure to the functional forms that underline the behavior of how the mean of and variation in the firm’s added value are regulated over time, as well as for the risk propensity of the firm’s owner. This exercise allow me to study the conditions under which the switching time should be delayed or expedited, and to numerically investigate the behavior of a firm’s total valuation as changes occur in key model parameters. I use franchising as an application of the sensitivity analysis I perform to identify whether a change in a model parameter (everything else being equal) should delay or expedite the orientation switch. Based on this application, I would advise entrepreneurs to switch their orientation later if they go into entrepreneurship as a franchisee rather than as a franchisor. A simulation analysis allows me to further propose a positive relationship between a firm’s total valuation and the planned added value by the entrepreneur to that firm. That analysis also suggests a positive relationship between a firm’s total valuation and the expected unplanned-added-value growth under a profit orientation, but a negative relationship under a survival orientation. Further, I find a positive relationship between total valuation and the variation in unplanned-added-value growth under a survival orientation, but a negative relationship under a profit orientation. One of the key challenges that have been raised for future entrepreneurship research is how to define an entrepreneur’s objective function. My thesis contributes to this debate by suggesting that, in the early years, there should be an orientation switch, that is, sequentially as opposed to simultaneously consider both survival and profit maximization. My thesis also contributes to the literature on firm growth because using risk-return tradeoffs to characterize the two orientations is unique in the entrepreneurial context, and so is the consideration of a sequential use of these orientations to study firm added value over time and the resulting accumulated total valuation. Characterizing each of the two orientations – survival and profit – based on risk-return tradeoffs and linking these orientations to firm growth open up new avenues for research in entrepreneurial decision making.

Modern communication systems operate with high peak-to-average-power ratio (PAPR) over wide bandwidth. Linearity requirements force operation in a low efficient highly linear back-off region. Then increasing efficiency is becoming critical. One of the most promising technologies to accomplish this is using supply modulation, e.g. envelope tracking (ET) and envelope elimination and restoration (EER). Supply modulated systems have been studied extensively in the past years, but no systems have been presented with flexibility in the envelope amplifier circuit.   In this work the supply modulator amplifiers have been studied. The focus is on hybrid switching amplifier (HSA) as envelope amplifier. Two envelope amplifier prototypes P-I and P-II have been designed. They are both designed for 15W output but P-II has 28V maximum supply voltage and P-I has 15V maximum supply voltage. P-II developed in version A, using silicon (Si) based switching transistor and version B using gallium-nitride (GaN) switching transistor. The efficiency is limited to a maximum 97 % possible by the circuit components.   The linearity was mainly analyzed by AM-AM diagrams. P-I, P-IIA and P-IIB, were analyzed in simulations and measurements. Results show high possibility of improvement with digital processing, i.e. digital pre-distortion (DPD). Linearization will improve the overall performance in the supply modulator (SM) systems, improving the delay issues and distortion produced by the implementation of the system.   The developed flexible board has made it possible to investigate alternative technologies of ET, focused in the hybrid switching amplifier (HSA). This has given the possibility to compare the overall performance for a traditional Si based switch with the novel Ferdinand Braun Institute’s (FBH) GaN-HEMT based switch with regards to bandwidth, efficiency and non-linearities introduced by the envelope tracking amplifier. P-I and P-II show high efficiency (> 60%) in results. For signals with adequate average power levels the efficiency is high, with around 70% efficiency for WCDMA signals. Phase distortions are evident already at a 5 MHz bandwidth.

In this article we use spatial birth-death processes to estimate the number of states k of a switching model. Following Preston (1976) and Stephens (1998) matching the detailed balance condition for the underlying birth-death process results in an unique invariant probability measure with the corresponding stationary distribution of the number of states. This concept could be easily integrated to Bayesian sampling to derive the marginal posterior distribution of the number of states within the sampling procedure. We apply this technique to simulated AR(1)data and to quarterly Austrian data on unemployment and real gross domestic product. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

Okun's Law postulates an inverse relationship between movements of the unemployment rate and the real gross domestic product (GDP). Empirical estimates for US data indicate that a two to three percent GDP growth rate above the natural or average GDP growth rate causes unemployment to decrease by one percentage point and vice versa. In this investigation we check whether this postulated relationship exhibits structural breaks by means of Markov-Chain Monte Carlo methods. We estimate a regression model, where the parameters are allowed to switch between different states and the switching process is Markov. As a by-product we derive an estimate of the current state within the periods considered. Using quarterly Austrian data on unemployment and real GDP from 1977 to 1995 we infer only one state, i.e. there are no structural breaks. The estimated parameters demand for an excess GDP growth rate of 4.16% to decrease unemployment by one percentage point. Since only one state is inferred, we conclude that the Austrian economy exhibits a stable relationship between unemployment and GDP growth. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

What objective should an entrepreneur focus on when starting a new business enterprise? Both a survival orientation and a profit one are important for the continuity of the new venture, but a survival focus is key in the hazardous early months or even years. In this thesis, I identify the conditions under which an entrepreneur should switch from a survival orientation, where the venture’s likelihood of survival is more critical, to a profit orientation where the venture’s profit instead is more critical. I accomplish this task by determining the optimal time to switch from a survival to a profit orientation based on maximizing the entrepreneur’s accumulated utility over a given time horizon. At each time period, the utility is positively associated with the amount of added value to the business venture that entrepreneur owns and manages, and the time horizon is determined by the time at which the entrepreneur’s venture exit – for instance, it is being sold. That added value contains a planned portion (e.g., due to what the entrepreneur can control) and an unplanned portion. The portion of a firm’s added value that is unplanned depends on the entrepreneur’s orientation, whereby, at any time period, the expected added value and its variation are considered to be low under a survival orientation, but they are considered to be high under a profit orientation. I use an approach from the economics literature, known as the LEN model, where the use of an exponential utility function (E), a linear relationship between the utility and random effects (L), and normality of those random effects (N) allow me to transfer the probabilistic objective function into a certainty equivalent that makes the problem tractable. The decision framework and its resulting findings suggest two environmental and two entrepreneurial characteristics that influence the existence of a time at which to switch orientation from survival to profit. Based on these characteristics, I derive sixteen scenarios and discussed some of the necessary conditions for the existence of a switching time. I find that it is not straightforward to determine whether the orientation switch should be delayed or expedited as business environments (or entrepreneurial types) are compared. I thus further develop my analysis by adding more structure to the functional forms that underline the behavior of how the mean of and variation in the firm’s added value are regulated over time, as well as for the risk propensity of the firm’s owner. This exercise allow me to study the conditions under which the switching time should be delayed or expedited, and to numerically investigate the behavior of a firm’s total valuation as changes occur in key model parameters. I use franchising as an application of the sensitivity analysis I perform to identify whether a change in a model parameter (everything else being equal) should delay or expedite the orientation switch. Based on this application, I would advise entrepreneurs to switch their orientation later if they go into entrepreneurship as a franchisee rather than as a franchisor. A simulation analysis allows me to further propose a positive relationship between a firm’s total valuation and the planned added value by the entrepreneur to that firm. That analysis also suggests a positive relationship between a firm’s total valuation and the expected unplanned-added-value growth under a profit orientation, but a negative relationship under a survival orientation. Further, I find a positive relationship between total valuation and the variation in unplanned-added-value growth under a survival orientation, but a negative relationship under a profit orientation. One of the key challenges that have been raised for future entrepreneurship research is how to define an entrepreneur’s objective function. My thesis contributes to this debate by suggesting that, in the early years, there should be an orientation switch, that is, sequentially as opposed to simultaneously consider both survival and profit maximization. My thesis also contributes to the literature on firm growth because using risk-return tradeoffs to characterize the two orientations is unique in the entrepreneurial context, and so is the consideration of a sequential use of these orientations to study firm added value over time and the resulting accumulated total valuation. Characterizing each of the two orientations – survival and profit – based on risk-return tradeoffs and linking these orientations to firm growth open up new avenues for research in entrepreneurial decision making.