No description available.

Palmaria palmata and Chondrus crispus were cultured in the lab at three levels of temperature and two of nitrate, representative of commercial Atlantic halibut farming conditions. Productivity and nitrogen removal by P. palmata were greatest at temperatures <10°C. Productivity of C. crispus was greatest at >10°C, while nitrogen removal was unaffected by temperature, 6-17°C. When cultured in various nitrate and ammonium combinations, nitrogen uptake was highest when available as ammonium. Both species took up 89-100% of ammonium in 24 hours, but only 23-37% and 55-87% of nitrate was taken up by P. palmata and C. crispus, respectively. When P. palmata was integrated with halibut recirculating aquaculture, productivity and nutrient removal were compromised during summer. During winter, <11°C, nitrogen removal by P. palmata was relatively stable at 2.3 gN m-2 d-1. For 50% nitrogen removal from halibut aquaculture during winter, a finfish: seaweed biomass of 1: 1 would be required.

Multi-level converters that provide more than two levels of voltage to achieve an output waveform closer to sinusoidal waveform with less distortion are very attractive to power applications. This thesis investigates several multi-level converter topologies and different modulation strategies such as pulse-width modulation and space vector modulation. Attention is paid in particular to SVM strategy. Although SVM strategy is applicable for N-level converter, this thesis only focuses on five-level and three-level diode clamped converter (DCC). Despite their appealing harmonic spectrum and low losses, multi-level converters are known to suffer from inherent voltage imbalance on their dc side. The thesis presents a method in order to balance the dc side capacitor voltages for an N-level converter. The presented balancing method is based on minimizing a cost function which is related to voltage divergence of the dc capacitors. This method is used for a three-level SVM to overcome the voltage drifting problem.

The emergence of multi-core processors has successfully ended the era where applications could enjoy free and regular performance improvements without source code modifications. This thesis aims to gather experiences from the work of retrofitting parallelism into a desktop application originally written for sequential execution. The main contribution is the underlying theory and the performance evaluation, experiments and tests of the parallel software regions compared to its sequential counterparts. The feasibility is demonstrated as the theory is put into use when a complex commercially active desktop application is being rewritten to support parallelism. The thesis finds no simple guaranteed solution to the problem of making a serial application execute in parallel. However, experiments and tests proves that many of the evaluated methods offers tangible performance advantages compared to sequential execution.

The research described in this thesis is an attempt to utilize the Model Driven Architecture for semi-automatically developing a prototype Multi-Agent System to support the management of a real container terminal. Agent technology has been increasingly applied in Transport Logistics and seems to be a viable solution to support the container terminal management. Thus, from the user point of view, the focus of this research is to investigate the applicability of Multi-Agent Systems to assist the container terminal's decision makers in improving the container terminal productivity, which is often measured in terms of the productivity of cranes. A prototype Multi-Agent System has been developed to evaluate and compare a set of proposed vehicle dispatching strategies, which are a collection of rules that a vehicle (e.g. straddle carrier) uses to decide the priority of serving the working cranes. Employing an appropriate dispatching strategy may greatly improve the efficiency of vehicle allocation to the working cranes, so as to increase the utilization of cranes which directly enhance the container terminal productivity. In order to investigate the applicability of the Multi-Agent System for supporting the container terminal management, experiments have been conducted in a variety of real-world scenarios. The experiment results have revealed that Multi-Agent Systems are applicable to assist container terminal decision makers in evaluating operating strategies. On the other hand, from the developer point of view, the author investigates how to apply the Model Driven Architecture to agent technologies, providing a partially automated support for the derivation of Multi-Agent System implementation from the agent-oriented design, independently from the target implementation platforms. The Model Driven Architecture approach studied in this research is a model-driven software development process that explicitly separates models at three different levels of abstraction: platform independent models, platform specific models, and implementation models. In contrast to the conventional code-centric software development, the Model Driven Architecture based software development uses models as the primary engineering artifacts. The adopted development approach is to take a high-level abstraction model of a system and transform it into a set of platform specific models, each of which is in turn transformed into the corresponding implementation. Transformations between models are automatically carried out by a set of transformation tools. The experience of using the Model Driven Architecture for the development of the prototype Multi-Agent System has revealed the following benefits: (a) automated transformations between models increase software productivity; (b) separating the high-level specification of the system from the underlying implementation technology improves the portability of the system's high-level abstraction model; (c) strong separation of concerns, guaranteed consistency between models, and automatic generation of source code minimize future software maintenance effort.

No description available.

Multi-level converters that provide more than two levels of voltage to achieve an output waveform closer to sinusoidal waveform with less distortion are very attractive to power applications. This thesis investigates several multi-level converter topologies and different modulation strategies such as pulse-width modulation and space vector modulation. Attention is paid in particular to SVM strategy. Although SVM strategy is applicable for N-level converter, this thesis only focuses on five-level and three-level diode clamped converter (DCC). Despite their appealing harmonic spectrum and low losses, multi-level converters are known to suffer from inherent voltage imbalance on their dc side. The thesis presents a method in order to balance the dc side capacitor voltages for an N-level converter. The presented balancing method is based on minimizing a cost function which is related to voltage divergence of the dc capacitors. This method is used for a three-level SVM to overcome the voltage drifting problem.

No description available.

No description available.

The research described in this thesis is an attempt to utilize the Model Driven Architecture for semi-automatically developing a prototype Multi-Agent System to support the management of a real container terminal. Agent technology has been increasingly applied in Transport Logistics and seems to be a viable solution to support the container terminal management. Thus, from the user point of view, the focus of this research is to investigate the applicability of Multi-Agent Systems to assist the container terminal's decision makers in improving the container terminal productivity, which is often measured in terms of the productivity of cranes. A prototype Multi-Agent System has been developed to evaluate and compare a set of proposed vehicle dispatching strategies, which are a collection of rules that a vehicle (e.g. straddle carrier) uses to decide the priority of serving the working cranes. Employing an appropriate dispatching strategy may greatly improve the efficiency of vehicle allocation to the working cranes, so as to increase the utilization of cranes which directly enhance the container terminal productivity. In order to investigate the applicability of the Multi-Agent System for supporting the container terminal management, experiments have been conducted in a variety of real-world scenarios. The experiment results have revealed that Multi-Agent Systems are applicable to assist container terminal decision makers in evaluating operating strategies. On the other hand, from the developer point of view, the author investigates how to apply the Model Driven Architecture to agent technologies, providing a partially automated support for the derivation of Multi-Agent System implementation from the agent-oriented design, independently from the target implementation platforms. The Model Driven Architecture approach studied in this research is a model-driven software development process that explicitly separates models at three different levels of abstraction: platform independent models, platform specific models, and implementation models. In contrast to the conventional code-centric software development, the Model Driven Architecture based software development uses models as the primary engineering artifacts. The adopted development approach is to take a high-level abstraction model of a system and transform it into a set of platform specific models, each of which is in turn transformed into the corresponding implementation. Transformations between models are automatically carried out by a set of transformation tools. The experience of using the Model Driven Architecture for the development of the prototype Multi-Agent System has revealed the following benefits: (a) automated transformations between models increase software productivity; (b) separating the high-level specification of the system from the underlying implementation technology improves the portability of the system's high-level abstraction model; (c) strong separation of concerns, guaranteed consistency between models, and automatic generation of source code minimize future software maintenance effort.