A Rationale for Tying Merchants' Membership of Platforms Serving Independent Markets. This thesis was submitted to the University of Manchester for the degree of Doctor of Social Sciences in the Faculty of Humanities by Michael King during September 2010. I analyses the effect of tying sellers' membership of a monopoly platform to membership of another platform, which operates in an otherwise competitive market. Visa's contentious use of the honour-all-cards rule to tie their debit and credit cards is an example of such a tie-in. There has been a move to judge tying cases under "rule of reason", which permits dubious practices when they are indispensable to creating economic benefit. However, a proportion of the extra-surplus must be passed on to consumers ("pass on test"). Rochet and Tirole (2008) claimed that tying payment cards raised Visa's profit without harming end-users. However, this doesn't fully address the concerns of regulators. Hence, my thesis investigates whether tying satisfied the "pass on test". Part I: In Rochet-Tirole (2008) sellers operate in two independent markets (ç and d). Network A runs platforms in both markets; and Network B only operates in market d. The price-level (buyer-fee plus seller-fee) on a network's platforms is exogenously determined but they can choose the price-structure. My study extended this framework by explicitly modelling competition in the product market. Part II: Platform competition leads to a price-structure that maximizes the net-benefit received by buyers and sellers. In contrast, a monopoly platform extracts most of the surplus by encouraging excessive use of payment-cards. Therefore, if tying is prohibited, then competition for sellers in market d leads to an optimal price-structure. However, Network A extracts most of the surplus created by its monopoly platform. Finally, if the average transaction-cost, τ, exceeds the price-level, ρ, then the net-benefit generated by a monopoly platform remains strictly positive. Part III: By tying its platforms Network A can exclude Network B. However, Network A is unable to exclude Network B just by matching the net-benefit it generates; rather, it must "compensate" sellers for the extra competition they face from being on the same network. Therefore, if tying is permitted, then the total net-benefit on Network A exceeds the maximum benefit that can be generated by a single platform. Part IV: It was found that if transaction-fees, ρ, are high relative to transaction-costs, τ, then tying always increases the consumer surplus. However, if transaction-fees, ρ, are low relative to transaction-costs, τ, then tying doesn't benefit consumers; and will reduce the consumer-surplus if their transaction-costs are sufficiently high.

Parallel computing offers immense potential to solve large, complex scientific problems. Load imbalance is a major impediment in obtaining high performance by a parallel system. One principal form of parallelism found in scientific applications is data parallelism. Loops without dependencies are data parallel. During the execution of large parallel loops, computational requirements vary due to problem, algorithmic and systemic characteristics. These factors lead to load imbalance which in turn degrades the performance of an application. Over the years, a number of dynamic loop scheduling techniques have been proposed to address one or more of these factors. However, there is no single strategy that works well for different problem domains and system characteristics. Moreover, load balancing during runtime is complicated because of its need for dynamic data redistribution. Therefore, there is a distinct need to integrate the dynamic loop scheduling techniques into a single package and provide them as an application programming interface (API) to the application developer. In recent years, along this direction, a number of dynamic loop scheduling techniques have been integrated into the compiler technologies for shared memory environments. On the other hand, there is no such integrated approach for distributed memory applications. The purpose of this thesis is to present the design, implementation and effectiveness of an integrated approach:the dynamic loop scheduling techniques are integrated into a runtime system for distributed memory architectures. For this purpose, we choose the newly developed parallel runtime environment for multicomputer architecture (PREMA) with its main components: the data movement and control substrate (DMCS) and mobile object layer (MOL). This runtime system has recently been developed and has demonstrated to be one of the most competitive runtime systems for distributed memory architectures. The significance of this work is that the proposed API will enhance the performance of parallel applications by reducing the load imbalance among processors caused by a wide range of factors and will reduce the software developmental cost required for load balancing. With the integration of the scheduling capabilities into the runtime system, its applicability has been expanded. The performance of the API has been evaluated qualitatively and quantitatively. The overhead of the API has been studied analytically and measured experimentally. Three parallel benchmarks including scientific applications of general interest (N-body simulations, automatic quadrature routine and unstructured grid heat solver) were considered for experimentation purpose. Based on the experiments conducted, a cost improvement of up to 76% over the straight forward parallel benchmark has been obtained. For certain application characteristics, the overhead of the runtime system was found to be within 10% of the underlying messaging layer. These results demonstrate that, in large scientific applications it is possible and desirable to combine the rich functionality of a runtime system with the advantages of scheduling techniques to achieve high performance.

Power electronics is a constantly growing and demanding technical field. Consumer demand and developing technologies have made the improvement of power density a primary emphasis of research for this area. Power semiconductors present some of the major challenges for increasing system level power density due to high loss density and interconnection requirements. Advanced cooling schemes, such as double-sided, forced liquid convection or multi-phase flow, can be implemented with non-wire bond packaging to improve thermal management while maintaining proper electrical performance. Embedded power is one such packaging technology, which provides a compact structure for interface of power semiconductor to fluid flow. The objective of this work was to identify the potential of implementing embedded power packaging with double-sided forced liquid convection. Physics based, electro-thermal models were first used to predict the improvement in heat transfer of double-sided, forced liquid convection with embedded power packaging over single-sided liquid cooled wire bond based packaging. A liquid module test bed was designed and constructed based on the electro-thermal models, which could be interfaced with high power MOSFET based samples implementing various packaging technologies. Experiments were used to verify the model predictions and identify practical limitations of high flow rate, double-sided liquid cooling with embedded power. An improvement of 45% to 60% in total junction to case thermal resistance is shown for embedded power packaging with double-sided liquid cooling for water flow rates between 0.25 and 4.5 gal/min. / Master of Science

Environmental cues such as day length and temperature contribute to timing of biological rhythms in seasonal breeders. Life-history transitions such as spring emergence from hibernation, migration, or mating must be coordinated with environmental conditions or survival is compromised. Therefore, there must be chemical signaling pathways in the brain that transduce seasonally-changing sensory inputs into signals that initiate a hormonal cascade, culminating in reproductive behavior. The relative importance of environmental cues to reproductive timing varies with species, time of year, and sex, and the mechanisms driving these differences remain unknown. The role of photoperiod in regulating reproductive behavior has been explored in birds and mammals, but much less is known about the role of so-called supplementary cues such as temperature, which is crucial in the timing of ectotherm reproduction. This is a critical gap in our knowledge, because shifts in seasonal temperatures due to climate change could create a mismatch between peak reproductive behavior and resources necessary for gestation and offspring survival. Deiodinase 2 (DIO2) enzyme is a critical component of the pathway that mediates reproduction in photoperiod-activated seasonal breeders, but whether deiodinase 2 is sensitive to seasonal changes in environmental temperature is unknown. In this study, we used an ectothermic vertebrate known to be a temperature-activated seasonal breeder, the red-sided garter snake (Thamnophis sirtalis parietalis), to investigate changes in hypothalamic DIO2 in response to hibernation at 4°C and 12°C. We captured male and female snakes in Manitoba, Canada as they returned to their winter den site from summer feeding grounds. Snakes were hibernated in complete darkness at either 4°C or 12°C for up to 16 weeks. A subset of each sex and temperature group were euthanized at intervals, and the brains collected and processed for DIO2 immunohistochemistry. DIO2-specific staining was found in the anterior hypothalamus, in the periventricular hypothalamic nucleus and ventral pre-optic area, along the longitudinally central region of the olfactory tract, in the bed nucleus of the stria terminalis, caudally in the cortex and optic tectum, and in the lateral septal nucleus. DIO2-stained area in the anterior hypothalamus was quantified. Male T. sirtalis in both the 4°C and 12°C groups were found to have an increase in DIO2-specific staining in the anterior hypothalamus after 8 weeks in hibernation. Female T. sirtalis were found to have an increase in DIO2-specific staining in the anterior hypothalamus after 8 weeks in the 12°C group only. These findings shed light on the neuroendocrine pathway through which environmental cues other than photoperiod influence the timing of seasonal reproduction, and support the hypothesis that at least some components of this pathway are conserved across seasonal breeders.

Cross-sided network effect is critical to platform based business models. In general, across a platform there¡¦re two types of users, each sitting on one side of the platform. And the platform¡¦s utility to any user in one side depends on the number of users (or the volume of usage generated by the users) in the other side. Under the discipline of micro-economy, cross-sided network effect is modeled and analyzed in the literature of ¡§two-sided markets¡¨. In this article, taking eWallet (electronically stored-value payment card) service as an example, we build a model of two-sided market, define and derive the utility functions for the platforms, and design a simulation to examine the price competition games in a duopoly market. We observe that, cross-sided network effect triggers variations in duopoly price games. By elaborating the business implication of these price game variants, we provide business intelligence for competing platforms in two-sided markets. Following the practice of game theory analysis, with our simulation we identify some famous game patterns such as prisoner¡¦s dilemma, race-around, and varies boxed-pigs games. Depending on the game pattern presented, managers can develop their own co-opetition strategy by leveraging the existing business intelligence provided in the literature of game theory. By factoring price elasticity, churn rate, strength of network effect and market share distribution in our algebraic model, we also derive the optimized prices with which incumbents and entrants can maximize their revenue in cooperative and competitive business environments. There¡¦s a growing interest in platform based business models, in which cross-sided network effect plays an important role. Our work helps to provide strategic suggestion for fixed¡Vtransaction¡Vfee platforms (such as eWallet), provide an systematic analysis methodology for platform based business models, and also provide a theoretic basics for further study in this critical area.

Under digital convergence, the market structure has changed which cause the traditional market definition is no longer applicable. Many industries and firms have take action of cross-industry M&A and integration. In contrast, regulations and ¡§new¡¨ market definition has not appeared which cause antitrust authorities deal with the case of the M&A under digital convergence has no quantitative tools. Our study has found that the market structure under digital convergence almost is two-sided market and multi-sided market, so we use the modified Critical Loss Analysis which Evans and Noel (2008) proposed to be the market definition tool under digital convergence. Subsequently, we use the merger case of TFN media and Kbro to do empirical analysis. By the empirical results, we find out that the relevant market of cable TV has to expand. The IPTV and online play will be the competitive product that the market structure of cable TV will be changed radically. Under digital convergence, market definition may not precisely than traditional, but it still could provide antitrust authorities an effective quantitative evidence, and with the economic theory of qualitative analysis which could make policy analysis more integrity.

Resource availability follows seasonal cycles in environmental conditions. To align physiology and behavior with prevailing environmental conditions, seasonal animals integrate cues from the environment with their internal state. One of the systems animals use to integrate those cues is the hypothalamus-pituitary-adrenal (HPA) axis and its primary effector, glucocorticoid hormones. The HPA axis has wide-ranging effects on physiology and behavior and, in the context of a glucocorticoid stress response, is known to mediate tradeoffs between immediate survival and future fitness. The HPA axis also plays an important role in facilitating predictable life-history events. Variation in HPA axis activity has been reported in all vertebrates, often coordinating seasonal reproduction and possibly also transitions between life-history stages. My dissertation research used red-sided garter snakes (Thamnophis sirtalis parietalis) to examine the role of the HPA axis in regulating seasonal life-history transitions, especially in females. In Chapter 2, I hypothesized that seasonal plasticity in stress responses is regulated, in part, by changes in the responsiveness of the adrenal glands to adrenocorticotropic hormone (ACTH). I found that glucocorticoid responses to ACTH challenge were smaller in males than in females during the spring, suggesting that reports of reduced stress responsiveness in males may reflect lower adrenal responsiveness to ACTH. The sex difference in mating season duration and consequently also in the timing of migration led me to hypothesize that sex differences in HPA axis activity could explain sex differences in the timing of migration. Furthermore, adrenal responsiveness to ACTH also varied seasonally in males, but not females, suggesting that female stress responses, which have not been studied, may not vary seasonally. In Chapter 3, I investigated potential seasonal variation in female stress responses, which have not previously been examined. In males, baseline glucocorticoids decrease over the course of the mating season resulting in significantly lower baseline levels in males that have begun to migrate. I hypothesized that a change in HPA axis activity occurs during spring and fall migration. Peak stress-induced glucocorticoid concentration occurred at an earlier sampling time in females during the spring compared to the fall. Peak stress-induced glucocorticoid concentrations also occurred at a later sampling time in migrating females than in pre-migratory females during the spring, suggesting that negative feedback regulation of the HPA axis changes as soon as females begin to migrate during the spring. Female red-sided garter snakes are biennial breeders that give birth approximately every other year implying that a female's recent reproductive history can influence whether or not she will reproduce in a given year. Body condition can be used as a proxy for recent reproductive history and can be related to baseline and stress-induced glucocorticoid concentrations. In Chapter 4, I hypothesized that hormonal and behavioral stress responses vary with body condition. Baseline glucocorticoids did not vary with body condition, but females in low body condition showed a significantly larger increase in plasma glucocorticoids in response to capture stress. Body condition, but not capture stress, influenced latency to copulate, suggesting that females are resistant to the behavioral effects of capture stress during the spring mating season. Only females in low body condition increased latency to copulate in response to injection of a physiological (15 µg) dose of exogenous CORT, while all females responded to a pharmacological (60 µg) dose, indicating that behavioral responses to exogenous glucocorticoids vary with female body condition. These data suggest that variation in body condition may be associated with differences in HPA axis sensitivity and/or glucocorticoid receptor (GR) density in the brain. I directly tested if there is a relationship among body condition, reproductive history and HPA axis activity in Chapter 5. I found that glucocorticoid stress responses and mating behavior did not vary with body condition, nor was body condition related to brain GR or reproductive condition (parturient vs post-parturient females). Only unreceptive females showed a significant stress-induced increase in glucocorticoids, suggesting that reduced stress responsiveness is associated with receptivity. Parturient females mated faster (were more proceptive) than post-parturient females. These data suggest that HPA axis activity influences reproductive "decisions" by modulating receptivity, while proceptivity is related primarily to recent reproductive history. Together, these chapters help characterize how HPA axis activity varies with season, sex, reproductive history and migration status. By systematically probing the HPA axis in a single, tractable system, I have gained insight into how changes in the HPA axis support and modulate transitions between life-history stages. These results highlight the HPA axis' important function in mediating the critical trade-offs all animals must navigate to be successful in a changing world.

No description available.

Magíster en Economía Aplicada. Ingeniero Civil Industrial / El presente trabajo estudia la infinita interacción descentralizada de un mercado two-sided, el cual se comporta de manera análoga a una fiesta, donde hombres y mujeres se emparejan a partir de propuestas de baile. En cada instante, cualquiera de los dos podría abandonar al otro para obtener una mejor asignación, teniendo todos un factor de descuento común $\delta$. Utilizando como refinamiento al equilibrio Markoviano perfecto (restringido en cuanto a la formación de nuevas parejas), se analiza la relación entre el conjunto de matchings estables $\Matchingset^*$ y el conjunto de asignaciones $\Agreeset_{\delta}$ ante el cual ya no se generen más ``cambios'' dentro de la fiesta, entendiendo a estos últimos como ``acuerdos''. Los resultados son que: (1) todo acuerdo debe ser estable, es decir, $\Agreeset_{\delta} \subseteq \Matchingset^*$; (2) en caso de existir más de un \textit{matching} estable, existe un $\hat{\delta}$ fijo tal que $\Agreeset_{\delta \geq \hat{\delta}} \subset \Matchingset^*$; (3) los incentivos opuestos del mercado son los generan que matchings estables puedan no ser acuerdos en la fiesta. La contribución de esta investigación viene dada por mostrar que los incentivos opuestos entre los dos lados del mercado, no permiten a los agentes alcanzar o mantener asignaciones estables de manera perpetua a lo largo del tiempo.

The reflectarray has been considered as a suitable candidate to replace the conventional parabolic reflectors because of its high-gain, low profile, and beam reconfiguration capability. Beam scanning capability and multi-band operation of the microstrip reflectarray have been main research topics in the reflectarray design. Narrow bandwidth of the reflectarray is the main obstacle for the various uses of the reflectarray. The wideband antenna element with a large phase variation range and a linear phase response is one of the solutions to increase the narrow bandwidth of the reflectarray. A four beam scanning reflectarray has been developed. It is the offset-fed microstrip reflectarray that has been developed to emulate a cylindrical reflector. Unlike other microstrip reflectarrays which integrates phase tuning devices such as RF MEMS switches and another phase shifters to the reflectarray elements and control the reflected phase, the beam scanning capability of the reflectarray is implemented by a phased array feed antenna. This method can reduce the complexity of the design of the beam switching reflectarray. A simple method has been investigated to develop multi-band elements in this dissertation. In approach to increase the coverage of the operation bands, a six-band reflectarray has been developed with two layers. Each layer covers three frequency bands. A Butler matrix is one of the useful beamforming networks for a phased array antenna. A Double-Sided Parallel-Strip Line (DSPSL) is adapted for the feeding network of eight array elements. The DSPSL operate very well to feed the microstrip antenna array over the bandwidth to reduce the sidelobe level and a high gain. In another topic of a Butler matrix, a dual-band Butler matrix has been proposed for multi-band applications. A modified Butler matrix is used to reduce a size and a sidelobe level. The bandwidth of the microstrip antenna is inherently small. A broadband circularly polarized microstrip antenna with dual-offset feedlines is introduced in this dissertation. Aperture-coupled feed method is used to feed the stacked patch antennas and a slotcoupled directional coupler is used for the circularly polarized operation. The research presented in this dissertation suggests useful techniques for a beam scanning microstrip reflectarray, phased array antenna, and wideband antenna designs in the modern wireless communication systems.