<p>Because of the slow access time of disk storage, storage management is crucial to the performance of many large scale computer systems. This thesis studies performance issues in buffer cache management and disk layout management, two important components of storage management. </p><p>The buffer cache stores popular disk pages in memory to speed up the access to them. Buffer cache management algorithms used in real systems often have many parameters that require careful hand-tuning to get good performance. A self-tuning algorithm is proposed to automatically tune the page cleaning activity in the buffer cache management algorithm by monitoring the I/O activities of the buffer cache. This algorithm achieves performance comparable to the best manually tuned system.</p><p>The global data structure used by the buffer cache management algorithm is protected by a lock. Access to this lock can cause contention which can significantly reduce system throughput in multi-processor systems. Current solutions to eliminate lock contention decrease the hit ratio of the buffer cache, which causes poor performance when the system is I/O-bound. A new approach, called the multi-region cache, is proposed. This approach eliminates lock contention, maintains the hit ratio of the buffer cache, and incurs little overhead. Moreover, this approach can be applied to most buffer cache management algorithms.</p><p>Disk layout management arranges the layout of pages on disks to improve the disk I/O efficiency. The typical disk layout approach, called Overwrite, is optimized for sequential I/Os from a single file. Interleaved writes from multiple users can significantly decrease system throughput in large scale systems using Overwrite. Although the Log-structured File System (LFS) is optimized for such workloads, its garbage collection overhead can be expensive. In modern and future disks, because of the much faster improvement of disk transfer bandwidth over disk positioning time, LFS performs much better than Overwrite in most workloads, unless the disk is close to full. A new disk layout approach, called HyLog, is proposed. HyLog achieves performance comparable to the best of existing disk layout approaches in most cases.

With power system restructuring, continuous growth of demand, and deregulation, small, scattered generators referred to as Distributed Generation (DG) are predicted to play a key role in the power distribution system. Moreover, among the different types of DG units, it is widely accepted that renewable DG units are the key to a sustainable energy supply infrastructure, since they are both inexhaustible and non-polluting. However the intermittent nature and the uncertainties associated with the renewable resources create special technical and economical challenges that have to be comprehensively investigated in order to facilitate the deployment of these DG units in the distribution system. The objective of the work proposed in this thesis is to tackle some of the challenges associated with the increased penetration of renewable DG units into existing distribution systems. This includes the study of the impact of different renewable DG units on the supply adequacy of the distribution system, and the development of planning technique that optimally allocate renewable DG units into the distribution system. Furthermore, a methodology is proposed to check the feasibility of implementing energy storage system (ESS) into the distribution system to mitigate the problems associated with the high penetration of renewable DG units. These problems include the maximum reverse power flow limit, the equipment rating limit, and the voltage limit on each bus. The first step toward the accomplishment of this work is to model the random behaviour of the renewable resources (i.e. wind speed and solar irradiance). Here, different approaches are proposed to model the random behaviour of both wind speed and solar irradiance, either chronologically or probabilistically. Among those approaches are a novel technique of annual wind speed estimation based on a constrained Grey predictor, and a new implementation of the probability density function (pdf) of the clearness index so as to model solar irradiance using Monte Carlo Simulation (MCS). Supply adequacy of distribution systems is assessed based on well-being criteria during different modes of operation (i.e. grid-connected mode and islanding mode), using analytical and (MCS) techniques. During the grid-connected mode, from the load perspective, the substation transformers act as generating units. Therefore, supply adequacy of distribution systems is assessed by considering that the generating units of the distribution system are the substation transformers and the DG units. During the islanding mode of operation, the island is acting as a small autonomous power system (SAPS) and the most important issue during this mode of operation is to determine the probability of the island to be successful (the DG power output within the island matches the load) or a failure (there is a deficit in power generation). The focus of the model developed to optimally allocate the renewable DG units in existing distribution systems is to minimize annual energy losses and at the same time, avoid any violation of the system constraints under any operating condition. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The objective function of the planning formulation is to minimize annual energy losses; whereas the constraints include the voltage limits, the feeders’ capacity, the maximum penetration limit, and the discrete size of the available DG units. The objective of the methodology proposed for allocating an ESS into distribution systems with high penetration (greater than 20% of the feeder capacity) of renewable energy is to maximize the benefits for both the DG owner and the utility. This is done by sizing the ESS to accommodate the entire surplus of renewable energy, and then allocating it within the system in order to minimize the annual cost of the electricity.

With power system restructuring, continuous growth of demand, and deregulation, small, scattered generators referred to as Distributed Generation (DG) are predicted to play a key role in the power distribution system. Moreover, among the different types of DG units, it is widely accepted that renewable DG units are the key to a sustainable energy supply infrastructure, since they are both inexhaustible and non-polluting. However the intermittent nature and the uncertainties associated with the renewable resources create special technical and economical challenges that have to be comprehensively investigated in order to facilitate the deployment of these DG units in the distribution system. The objective of the work proposed in this thesis is to tackle some of the challenges associated with the increased penetration of renewable DG units into existing distribution systems. This includes the study of the impact of different renewable DG units on the supply adequacy of the distribution system, and the development of planning technique that optimally allocate renewable DG units into the distribution system. Furthermore, a methodology is proposed to check the feasibility of implementing energy storage system (ESS) into the distribution system to mitigate the problems associated with the high penetration of renewable DG units. These problems include the maximum reverse power flow limit, the equipment rating limit, and the voltage limit on each bus. The first step toward the accomplishment of this work is to model the random behaviour of the renewable resources (i.e. wind speed and solar irradiance). Here, different approaches are proposed to model the random behaviour of both wind speed and solar irradiance, either chronologically or probabilistically. Among those approaches are a novel technique of annual wind speed estimation based on a constrained Grey predictor, and a new implementation of the probability density function (pdf) of the clearness index so as to model solar irradiance using Monte Carlo Simulation (MCS). Supply adequacy of distribution systems is assessed based on well-being criteria during different modes of operation (i.e. grid-connected mode and islanding mode), using analytical and (MCS) techniques. During the grid-connected mode, from the load perspective, the substation transformers act as generating units. Therefore, supply adequacy of distribution systems is assessed by considering that the generating units of the distribution system are the substation transformers and the DG units. During the islanding mode of operation, the island is acting as a small autonomous power system (SAPS) and the most important issue during this mode of operation is to determine the probability of the island to be successful (the DG power output within the island matches the load) or a failure (there is a deficit in power generation). The focus of the model developed to optimally allocate the renewable DG units in existing distribution systems is to minimize annual energy losses and at the same time, avoid any violation of the system constraints under any operating condition. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The objective function of the planning formulation is to minimize annual energy losses; whereas the constraints include the voltage limits, the feeders’ capacity, the maximum penetration limit, and the discrete size of the available DG units. The objective of the methodology proposed for allocating an ESS into distribution systems with high penetration (greater than 20% of the feeder capacity) of renewable energy is to maximize the benefits for both the DG owner and the utility. This is done by sizing the ESS to accommodate the entire surplus of renewable energy, and then allocating it within the system in order to minimize the annual cost of the electricity.

<p>Because of the slow access time of disk storage, storage management is crucial to the performance of many large scale computer systems. This thesis studies performance issues in buffer cache management and disk layout management, two important components of storage management. </p><p>The buffer cache stores popular disk pages in memory to speed up the access to them. Buffer cache management algorithms used in real systems often have many parameters that require careful hand-tuning to get good performance. A self-tuning algorithm is proposed to automatically tune the page cleaning activity in the buffer cache management algorithm by monitoring the I/O activities of the buffer cache. This algorithm achieves performance comparable to the best manually tuned system.</p><p>The global data structure used by the buffer cache management algorithm is protected by a lock. Access to this lock can cause contention which can significantly reduce system throughput in multi-processor systems. Current solutions to eliminate lock contention decrease the hit ratio of the buffer cache, which causes poor performance when the system is I/O-bound. A new approach, called the multi-region cache, is proposed. This approach eliminates lock contention, maintains the hit ratio of the buffer cache, and incurs little overhead. Moreover, this approach can be applied to most buffer cache management algorithms.</p><p>Disk layout management arranges the layout of pages on disks to improve the disk I/O efficiency. The typical disk layout approach, called Overwrite, is optimized for sequential I/Os from a single file. Interleaved writes from multiple users can significantly decrease system throughput in large scale systems using Overwrite. Although the Log-structured File System (LFS) is optimized for such workloads, its garbage collection overhead can be expensive. In modern and future disks, because of the much faster improvement of disk transfer bandwidth over disk positioning time, LFS performs much better than Overwrite in most workloads, unless the disk is close to full. A new disk layout approach, called HyLog, is proposed. HyLog achieves performance comparable to the best of existing disk layout approaches in most cases.

Thermal energy storage(TES) air-conditioning system is a electrical load management technology with great potential to shift load from peak to off-peak utility periods. TES is now in widespread use for electric rate structures and energy policies and becomes a great contribution to energy conservation. However, TES is more complicated than conventional air-conditioning system in design and control strategies. According to practical field operation, the control of dynamic characters is especially difficult, and so are storage capacity design , discharging rate and charging capacity selection. This study set an example how to improve the energy performance of a retrofitted thermal energy storage air-conditioning system of a marine museum. Through full-scale experiment, historical air-conditioning operation data and computer simulation, the solution is provided on condition of unchanging major water pipe and equipment. This example can be a good demonstration for upping performance of TES. After testing and recording data for one year, this case indicates the investigation is effective and valuable to electric power management and green technology.

Intermediate storage system optimization is an essential aspect which this report tends to look upon and putting effort on improving operating efficiency then reducing the capital cost of batch/ semi-continuous or flow production process by looking at the extent of estimating the figures of boxes that are made to be in the intermediate storage system through evaluations. Additionally, intermediate storage can reduce the effects of process parameter variations, such as recipe inaccuracies and operator errors, in which process operations are particularly visible. In a channel of operations, where there are many amount of shift that are inevitable to pass through in order to complete production process to get a finished product. Hence, longer operating horizon, process variations must include a measurable parameter, either shorter or longer to avoid failure of meeting product specification and limitation of meeting end users specification. Intermediate storage system as a back-up function in case of some sudden failure within the production line In this thesis, it is notable to make an amendment, as a way of knowing the accuracy of boxes of bearing work-piece that will be maintaining a certain intermediate storage system to feed the next shift of workstation in a continuous process with accurate or known estimated number of work-piece in a role, until the final product is been made. Hence, in this research, there are many theory that were adopted to give a clear view of what will be obtainable in the whole research both in empirical finding to have a definite result. To achieve the above goal this thesis followed a steps to fulfil its objective. Steps 1 and 2 were to know the strategic plans as well as operating methods through theory also, to know the production line balancing to have a view of time measured through the theory. Step 3 and 4 adoptions of theory and empirical finding to calculate, productivity through the source of cycle time, as well as facility plan and to give analysis of intermediate storage system, in optimization of production line to make a work flow achievable at the end, to meet the customers demand.

This bachelor thesis investigates the implementation of a solar panel and battery storage system in a Swedish church that is intermittently heated focusing on its economic effect and its environmental impact in terms of CO2 emissions. The models are developed to evaluate the costs and CO2 emissions associated with power production, storage, usage and installation of the implemented system. The thesis examines two cases: Case 1, where all the energy is bought from the grid, representing the current energy usage in many churches, and Case 2 which assumes the integration of a solar panel and battery storage system. In terms of economic effects, the thesis reveals that the solar panel and battery storage system results in a negative impact on the church’s costs regarding energy usage. Over a period of 25 years, the church is projected to incur a loss of 956 400 SEK. However, it is worth noting that the direct energy costs when having an implemented solar panel and battery storage system are reduced by 33%, and the sale of surplus solar power generates an income of 1 816 100 SEK. Regarding the environmental impact, the implementation of the solar panel and battery storage system results in increased emissions compared to when only consuming the Swedish electricity mix. This is mainly due to the emissions regarding manufacturing of the solar panel and battery storage system. However, it is visible that the implementation of solely solar panels would lower the system’s total CO2 emissions. The sensitivity analysis demonstrates that replacing the Swedish electricity mix with the EU electricity mix for sold solar energy results in a positive environmental impact. This since the power generated from the solar panels replaces the European electricity mix which has a higher CO2- emission equivalent. This is important to consider since it is impossible to determine which electricity mix the sold PV energy will replace. In conclusion, while the implementation of a solar panel and battery storage system negatively affects the church’s energy costs and leads to increased CO2 emissions in the examined case, there are certain benefits to consider. The reduced energy bought from the grid and lowered direct energy costs, as well as the revenue from selling surplus solar power establishes the potential for the system to provide a positive impact. However, there is a need for advancements in battery technology for this to be a possibility.

This research investigates the effects of both a Hybrid Energy Storage System and an Electrified Turbocharger in a consumer performance vehicle. This research also attempts to support the development of a prototype vehicle containing a Hybrid Energy Storage System currently being developed at McMaster University. Using a custom simulation tool developed in Matlab Simulink, Simulink models of each of the technologies were developed to predict the behavior of these subsystems across multiple physical domains. Control modeling, optimization and testing was completed for both systems. In addition, controls modeling for the Hybrid Energy Storage System was integrated with the development effort for a prototype vehicle considering the specifics of real world components. To assess the impact of these technologies on a performance vehicle platform, the simulation tool tested each technology using multiple vehicle variations. Three vehicle variants were developed, representing: a conventional performance hybrid design, a hybrid vehicle containing an electrified turbocharger, and a vehicle containing a Hybrid Energy Storage System. Electrical system peak output power was the vehicle specification held constant between each vehicle variant. Each vehicle variant was simulated against a number of traditional drive cycles representing everyday driving scenarios in an attempt to compare fuel economy while identifying each technologies individual impact on the vehicles performance. Finally, each vehicle variant was simulated using a custom performance drive cycle in a virtual race. Both technologies as assessed and in comparison to a larger battery variant, did not result in improved fuel economies during conventional vehicle driving. Both the Hybrid Energy Storage System and electrified turbocharger demonstrated improved vehicle performance in particular scenarios. / Thesis / Master of Applied Science (MASc) / Electrified vehicles have not typically been viewed as performance vehicles. A recent trend has seen a growing number of manufacturers turn to hybrid and electric powertrains to produce high performing vehicles. However, a performance vehicle's electrical power is conventionally limited by the size and power of its battery, adding weight and cost. Two technologies offer the ability to increase the power of these electrified components without the need for a large battery. First, Hybrid Energy Storage System combines ultra-capacitors and batteries to increase the power density of the system. Second, an Electrified Turbocharger improves the turbo lag of a turbocharged engine and also recovers waste heat energy from the exhaust gases which is then used to propel the vehicle. This research identifies and demonstrates the potential impact these two technologies have when included in an American Muscle Car.

This works begins by providing motivation for additional research and political interest in the use of passenger railway systems as a method of ‘green’ transportation. Additional motivation for the adoption of energy saving methods within new and existing railway systems is also provided. This motivation stems from the relatively small carbon dioxide emissions per passenger kilometer and large quantity of electrical energy used in association with passenger railway systems. In specific cases, both theoretical analyses and experimental implementations of energy storage in railway systems have shown a reduction in electrical energy use and/or vehicle performance gains. Current railway energy storage systems (ESS) commonly make use of battery or electric double layer capacitor (EDLC) cells. A review of select energy storage technologies and their application in railway systems is provided. For example, the developing Qatar Education City People Mover system makes use of energy dense batteries and power dense EDLCs to provide the range and power needed to operate without a conventional railway power source between stations, formally called catenary free operation. As an alternative to combining two distinct energy storage technologies, this work looks at experimentally characterizing the performance of commercially available lithium ion capacitors (LiCs); a relatively new energy storage cell that combines characteristics of batteries and EDLCs into one cell. The custom cell testing apparatus and lab safety systems used by this work, and others, is discussed. A series of five tests were performed on two EDLC cells and five LiC cells to evaluate their characteristics under various electrical load conditions at multiple temperatures. The general conclusion is that, in comparison to the EDLC cells tested, the LiC cells tested offer a superior energy density however, their power capabilities are relatively limited, especially in cold environments, due to larger equivalent series resistance values. The second topic explored in this work is the development of a MATLAB based DC powered passenger vehicle railway simulation tool. The simulation tool is connected to the experimental analysis of EDLC and LiC cells by comparing the volume and mass of an energy storage system needed for catenary free (no conventional DC power supply) operation between train stations using either energy storage technology. A backward facing modelling approach is used to quantify the drive cycle electrical power demands as a function of multiple vehicle parameters and driving parameters (eg. acceleration rate, travel distance and time). Additional modelling methods are provided as a resource to further develop the simulation tool to include multiple vehicles and their interactions with the DC power supply. Completion of the multi-vehicle simulation tool with energy storage systems remains a task for future work. / Thesis / Master of Applied Science (MASc)

This thesis focuses on the concept, design, and simulation of the Reconfigurable Multi-Source Inverter for EV applications and its effectiveness when combined with a HESS. The current trends in the automotive market, including different vehicle types, and the adoption of electrified vehicles by the public are discussed. The benefits and logistics of different vehicle architectures are analyzed and compared. Hybrid vehicles will be essential in helping transition society from conventional internal combustion engine vehicles to purely electric vehicles. The individual components of these electrified vehicles are reviewed, and common topologies are discussed with the benefits of each system compared. The batteries required for these electric vehicles are costly and require many individual cells in order to operate efficiently. Many hybrids vehicles make use of expensive power electronics, such as DC/DC converters to help boost the operating voltage of the battery pack without adding additional cells. A Reconfigurable Multi-Source Inverter in introduced and its switching structure is explained in depth. Its’ ability to make use of multiple DC sources to create four different voltage levels is outlined and possible modulation techniques are presented. This thesis aims to introduce a novel Reconfigurable Multi-Source Inverter using a Space Vector Pulse Width Modulation (SVPWM) scheme and is further investigated through simulations and with plans for experimental validation on an R-L load. / Thesis / Master of Applied Science (MASc) / One of the main factors affecting the cost of electrified vehicles is the expense of building a high voltage battery pack. Motor’s used in electric vehicle applications typically operate at higher voltages and therefore require large battery pack or costly power electronics to step the voltage of the pack up to a suitable operating level. A Reconfigurable Multi-Source Inverter uses a combination of two sources to create different voltage levels. This novel inverter can be used to maximize the voltage of smaller packs to help reduce the overall cost of vehicle electrification.