In this thesis, the improvement to relevance in computerized search results is studied. Information search tools return ranked lists of documents ordered by the relevance of the documents to the user supplied search. Using a small number of words and phrases to represent complex ideas and concepts causes user search queries to be information sparse. This sparsity challenges search tools to locate relevant documents for users. A review of the challenges to information searches helps to identify the problems and offer suggestions in improving current information search tools. Using the suggestions put forth by the Strategic Workshop on Information Retrieval in Lorne (SWIRL), a composite scoring approach (Composite Scorer) is developed. The Composite Scorer considers various aspects of information needs to improve the ranked results of search by returning records relevant to the user’s information need. The Florida Fusion Center (FFC), a local law enforcement agency has a need for a more effective information search tool. Daily, the agency processes large amounts of police reports typically written as text documents. Current information search methods require inordinate amounts of time and skill to identify relevant police reports from their large collection of police reports. An experiment conducted by FFC investigators contrasted the composite scoring approach against a common search scoring approach (TF/IDF). In the experiment, police investigators used a custom-built software interface to conduct several use case scenarios for searching for related documents to various criminal investigations. Those expert users then evaluated the results of the top ten ranked documents returned from both search scorers to measure the relevance to the user of the returned documents. The evaluations were collected and measurements used to evaluate the performance of the two scorers. A search with many irrelevant documents has a cost to the users in both time and potentially in unsolved crimes. A cost function contrasted the difference in cost between the two scoring methods for the use cases. Mean Average Precision (MAP) is a common method used to evaluate the performance of ranked list search results. MAP was computed for both scoring methods to provide a numeric value representing the accuracy of each scorer at returning relevant documents in the top-ten documents of a ranked list of search results. The purpose of this study is to determine if a composite scoring approach to ranked lists, that considers multiple aspects of a user’s search, can improve the quality of search, returning greater numbers of relevant documents during an information search. This research contributes to the understanding of composite scoring methods to improve search results. Understanding the value of composite scoring methods allows researchers to evaluate, explore and possibly extend the approach, incorporating other information aspects such as word and document meaning.

In this world of growing technology, any small improvement in the present scenario would create a revolution. One of the popular revolutions in the computer science field is parallel computing. A single parallel execution is not sufficient to see its non-deterministic features, as same execution with the same data at different time would end up with a different path. In order to see how non deterministic a parallel execution can extend up to, creates the need of the ensemble of executions. This project implements a program to estimate the Gibbs Entropy for an ensemble of parallel executions. The goal is to develop tools for studying the non-deterministic feature of parallel code based on execution entropy and use these developed tools for current and future research.

Rechargeable Li-ion batteries and supercapacitors are the most promising electrochemical energy storage devices in terms of energy density and power density, respectively. Recently, nanostructured materials have gained enormous interest in the field of energy technology as they have special properties compared to the bulk. Commercially available Li-ion batteries, which are the most advanced among the rechargeable batteries, utilize microcrystalline transition metal oxides as cathode materials which act as lithium insertion hosts. To explore better electrochemical performance the use of nanomaterials instead of conventional materials would be an excellent alternative. High Li-ion insertion at high discharge rates causes slow Li+ transport which in turn results in concentration polarization of lithium ions within the electrode material, causing a drop in cell voltage. This eventually, leads in termination of the discharge process before realizing the maximum capacity of the electrode material being used. This problem can be addressed by decreasing the average particle size which leads to an increase in surface area of the electrode material. Nanostructured materials, because of their high surface area and large surface to volume ratio, to some extent can overcome the problem of slow diffusion of ions. Supercapacitors are electrical energy storage devices which can deliver large energy in a short time. A supercapacitor can be used as an auxiliary energy device along with a primary source such as a battery or a fuel cell to achieve power enhancement in short pulse applications. Active materials for supercapacitors are classified into three categories: (i) carbonaceous materials, (ii) conducting polymers and (iii) metal oxides. Among the materials studied over the years, metal oxides have been considered as attractive electrode materials for supercapacitors due to the following merits: variable oxidation state, good chemical and electrochemical stability, ease of preparation and handling. The performance of supercapacitors can be enhanced by moving from bulk to nanostructured materials. The theme of the thesis is to explore novel routes to synthesize nanostructured materials for Li-ion batteries and supercapacitors, and to investigate their physical and electrochemical characteristics. Chapter I is an introduction of various types of electrochemical energy systems such as battery, fuel cell and supercapacitor. A brief review is made on electrode materials for Li-ion batteries and supercapacitors, and nanostructured materials. Chapter II deals with the study of nanostrip orthorhombic V2O5 synthesized by a two-step procedure, with the formation of a vanadyl ethylene glycolate precursor and post-calcination treatment. The precursor and the final product are characterized for phase and composition by powder X-ray diffraction (XRD), infrared (IR) spectroscopy, thermal analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The morphological changes are investigated using field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM). It is found that the individual strips have the following dimensions, length: 1.3 μm, width: 332 nm and thickness: 45 nm. The electrochemical lithium intercalation and de-intercalation of nanostrip V2O5 is investigated by cyclic voltammetry (CV), galvanostatic charge-discharge cycling, galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy. Chapter III describes the synthesis of nanoparticels of LiMn2O4 by microwave assisted hydrothermal method. The phase and purity of spinel LiMn2O4 are confirmed by powder XRD analysis. The morphological studies are carried out using FE-SEM and HRTEM. The electrochemical performance of spinel LiMn2O4 is studied by using CV and galvanostatic charge-discharge cycling. The initial discharge capacity is found to be about 89 mAh g-1 at a current density of 21 mA g-1 with reasonably good cyclability. Chapter IV deals with synthesis of MoO2 nanoparticles through ethylene glycol medium and its electrochemical characterization. XRD data confirms the formation MoO2 on monoclinic phase, space group P21/c. Polygon shape of MoO2 is observed in HRTEM. MoO2 facilitates reversible insertion-extraction of Li+ ions between 0.25 to 3.0 V vs. Li/Li+. CV and galvanostatic charge-discharge cycling are conducted on this anode material to complement the electrochemical data. Chapter V reports the synthesis of nanostructured MnO2 at ambient conditions by reduction of potassium permanganate with aniline. Physical characterization is carried out to identify the phase and morphology. The as prepared MnO2 is amorphous and it contains particles of 5 to 10 nm in diameter. On annealing at a temperature > 400 °C, the amorphous MnO2 attains crystalline α-phase with a concomitant change in morphology. A gradual conversion of nanoparticles to nanorods (length 500-750 nm and diameter 50-100 nm) is evident from SEM and TEM studies. High resolution TEM images suggest that nanoparticles and nanorods grow in different crystallographic planes. The electrochemical lithium intercalation and de-intercalation of nanorods was performed by (CV) and galvanostatic charge-discharge cycling. The initial discharge capacity of nanorod α-MnO2 is found to be about 197 mAh g-1 at a current density of 13.0 mA g-1. Capacitance behavior of amorphous MnO2 is studied by CV and galvanostatic charge-discharge cycling in a potential range from -0.2 to 1.0 V vs. SCE in 0.1 M sodium sulphate solution. The effect of annealing on specific capacitance is also investigated. Specific capacitance of about 250 F g-1 is obtained for as prepared MnO2 at a current density of 0.5 mA cm-2 (0.8 A g-1). Chapter VI pertains to electrochemical supercapacitor studies on nanostructured MnO2 synthesized by polyol method. Although X-ray diffraction (XRD) pattern of the as synthesized nano-MnO2 shows poor crystallinity, it is found that it is locally arranged in δ-MnO2 type layered structure composed of edge-shared network of MnO6 octahedra by Mn K-edge X-ray Absorption Near Edge Structure (XANES) measurement. Annealed MnO2 shows high crystalline tunneled based α-MnO2 as confirmed by powder XRD pattern and XANES. As synthesized MnO2 exhibits good cyclability as an electrode material for supercapacitor. In Chapter VII, capacitance behavior of nanostrip V2O5, TiO2 coated V2O5 and nanocomposites of PEDOT/V2O5 are presented. Structural and morphological studies are carried out by powder XRD, IR, TGA, SEM and TEM. Cyclic voltammogram of pristine V2O5 shows the regular rectangular shape indicating the ideal capacitance behavior in aqueous 0.1 M K2SO4. The SC value of pristine V2O5 is found to be about 100 F g-1. Nanostrip V2O5 is modified with TiO2 using titanium isobutoxide to enhance the capacitance retention upon cycling. Only 48 % of the initial capacitance remains in the case of pristine V2O5 after 100 cycles, while TiO2 coated V2O5 exhibits better cyclability with capacitance of 70 % of the initial capacitance. The capacitance retention is attributed to the presence of TiO2 on the surface of V2O5 which prevents the vanadium dissolution into the electrolyte. Microwave assisted hydrothermally synthesized PEDOT/V2O5 nanocomposites are utilized as capacitor materials. The initial SC of PEDOT/V2O5 (237 F g-1) is higher than that of either pristine V2O5 or PEDOT. The enhanced electrochemical performance is attributed to synergic effect and an enhanced bi-dimensionality. Details of the above studies are described in the thesis with a conclusion at the end of each Chapter.

A galvanic cell converts chemical energy into electrical energy. Devices that carry out these conversions are called batteries. In batteries, generally the chemical components are contained within the device itself. If the reactants are supplied from an external source as they are consumed, the device is called a fuel cell. A fuel cell converts chemical energy into electrical energy as long as the chemicals are supplied from external reserves. The working principle of a metal-air battery involves the principles of both batteries and fuel cells. The anode of a metal-air cell is stored inside the cell, whereas O2 for the air-electrode is supplied from either atmosphere or a tank. There are several metal-air batteries available academically, which include Zn-air, Alair, Fe-air, Mg-air, Ca-air, Li-air and Na-air batteries. So far, only Zn-air battery is successfully commercialized. Li-air battery is attractive compared to other metal-air batteries because of its high theoretical energy density (11140 Wh kg-1). The energy density of Li-air battery is 3 - 5 times greater than state-of-art Li-ion battery. Li-air (or Li-O2) battery comprises Li-metal as the anode and a porous cathode. The cathode and the anode are separated by a suitable separator soaked in an organic electrolyte. Atmospheric air can enter the battery through the porous cathode. Out of the mixture of gases present in the air, only O2 is electrochemically active. For optimization purpose, most of researchers use pure O2 gas instead of air. Li-air battery is not commercialized till now because of several issues associated with it. The issues include: (i) sluggish kinetics of O2 electrode reaction, (ii) decomposition of the electrolyte during charge-discharge cycling, (iii) formation of Li dendrites, (iv) contamination by moisture, etc. Among these scientific and technical problems related to Li-O2 cell system, studies on rechargeable O2 electrode with fast kinetics of oxygen reduction reaction (ORR) during the cell discharge and oxygen evolution reaction (OER) during charge in non-aqueous electrolytes are important. In non-aqueous electrolytes, the 1-electron reduction of O2 to form superoxide (O2 -) is known to occur as the first step. (ii) Subsequently, superoxide undergoes reduction to peroxide (O2 2-) and then to oxide (O2-). The kinetics of ORR is slow in non-aqueous electrolytes. Furthermore, the reaction needs to be reversible for rechargeable Li-air batteries. In order to realize fast kinetics, a suitable catalyst is essential. The catalyst should be bifunctional for both of ORR and OER in rechargeable battery applications. Noble metal particles have been rarely investigated as catalysts for O2 electrode of Li-O2 cells. Graphene has two-dimensional planar structure with sp2 bonded carbon atoms. It has become an important electrode material owing to its high electronic conductivity and large surface area. It has been investigated for applications such as supercapacitors, Li-ion batteries, and fuel cells. Catalyst nanoparticles prepared and anchored to graphene sheets are expected to sustain discrete existence without undergoing agglomeration and therefore they possess a high catalytic stability for long term experiments as well as applications. In this context, it is intended to explore the catalytic activity of noble metal nanoparticles dispersed on reduced graphene oxide (RGO) for O2 electrode of Li-O2 cells. While a majority of the investigations reported in the thesis involves noble metal and alloy particles dispersed on RGO sheets, results on polypyrrole-RGO composite and also magnesium cobalt silicate for Li-O2 system are included. A chapter on electrochemical impedance analysis of LiMn2O4, a cathode material of Li-ion batteries, is also presented in the thesis. Introduction on electrochemical energy storage systems, in particular on Li-O2 system is provided in the 1st Chapter of the thesis. Synthesis of Ag nanoparticles anchored to RGO and catalytic activity are presented in the 2nd Chapter. Ag-RGO is prepared by insitu reduction of Ag+ ions and graphene oxide in aqueous phase by ethylene glycol as the reducing agent. The product is characterized by powder XRD, UV-VIS, IR, Raman, AFM, XPS, SEM and TEM studies. The SEM images show the layered morphology of graphene and TEM images confirm the presence of Ag nanoparticles of average diameter less than 5 nm anchored to RGO (Fig. 1a). Ag-RGO is investigated for ORR in alkaline (1 M KOH), neutral (1 M K2SO4) and non-aqueous 0.1 M tetrabutyl ammonium perchlorate in dimethyl sulphoxide (TBAP-DMSO) electrolytes. The ORR follows 4e- reduction in aqueous and 1e- reduction pathway in non-aqueous electrolytes. Li-O2 cells are assembled with Ag-RGO as (iii) Fig. 1. (a) TEM image of Ag-RGO and (b) charge-discharge voltage profiles of Li-O2 (Ag-RGO) cells. oxygen electrode catalyst in non-aqueous electrolyte (1 M LiPF6-DMSO) and subjected to charge-discharge cycling at several current densities. The discharge capacity values obtained are 11950 (11.29), 9340 (5.00), and 2780 mAh g-1 (2.47 mAh cm-2) when discharged at 0.2, 0.5, 0.8 mA cm-2, respectively (Fig. 1b). Powder XRD studies of discharged electrodes indicate the formation of Li2O2 and Li2O during the cell discharge. In addition to these studies, Na-O2 cells are also assembled with Ag-RGO in non-aqueous electrolyte. It is concluded that the chemistry Li-O2 and Na-O2 cells are similar except for the capacity values. Metal nanoparticles of Au, Pd and Ir are decorated on RGO sheets by reduction of metal ions on graphene oxide by NaBH4. Au-RGO, Pd-RGO and Ir-RGO are characterized by various physicochemical techniques. Particle size of metal nanoparticles ranges from 2 to Fig.2. Charge-discharge voltage profiles Li-O2(RGO) (i) and Li-O2(Au-RGO) (ii) cells at current density 0.3 mA cm-2. 0 2500 5000 7500 10000 12500 15000 10 nm on graphene sheets. All samples are studied for ORR in aqueous and non-aqueous electrolytes by cyclic voltammetry and rotating disk electrode experiments. Li-O2 cells are assembled in 1 M LiPF6-DMSO and discharge capacity values obtained are 3344, 8192 and 11449 mAh g-1 with Au-RGO, Pd-RGO and Ir-RGO, respectively, at 0.2 mA cm-2 current density. The results of these studies are described in Chapter 3. Synthesis and electrochemical activity of Pt-based alloy nanoparticles (Pt3Ni, Pt3Co and Pt3Fe) on RGO are presented in Chapter 4. The Pt3Ni alloy particles are prepared by simultaneous reduction of Pt4+, Ni2+ and graphene oxide by hydrazine in ethylene glycol medium. Pt3Co-RGO and Pt3Fe-RGO are also prepared similar to Pt3Ni-RGO. Formation of alloys is confirmed with XRD studies. O2 reduction reaction on Pt-alloys in non-aqueous electrolyte follows 1e- reduction to O2 -. RDE results show that Pt3Ni-RGO is a better catalyst than Pt for O2 reduction (Fig. 3). Li-O2 cells are assembled with all samples and subjected to Fig. 3. Linear sweep voltammograms of Pt3Ni-RGO, Pt3Co-RGO and Pt3Fe-RGO in 0.1 M TBAPDMSO with 1600 rpm at 10 mV s-1 scan rate. The area of GC electrode was 0.0314 cm2 with a catalyst mass of 200 μg. charge-discharge cycling at several current densities. The initial discharge capacity values obtained are 14128, 5000 and 10500 mAh g-1 with Pt3Ni-RGO, Pt3Co-RGO and Pt3Fe-RGO, respectively, as the air electrode catalysts. Polypyrrole (PPY) is an attractive conducting polymer with advantages such as high electronic conductivity and electrochemical stability. A combination of advantages of graphene and PPY composite are explained in the Chapter 5. PPY is grown on already synthesized RGO sheets by oxidative polymerization of pyrrole in an acidic PY composite is characterized by XRD and Raman spectroscopy studies. Li-O2 cells are assembled in non-aqueous electrolyte and subjected for charge-discharge cycling at different current densities. The discharge capacity value of Li-O2(PPY-RGO) cell is 3358 mAh g-1 Fig. 4. (a) Discharge-charge performance of Li-O2(PPY-RGO) cell with a current density of 0.2 mA cm-2 limiting to a capacity of 1000 mAh g-1 and (b) variation of cut-off voltages on cycling. (3.94 mAh cm-2) in the first cycle. Li-O2(PPY-RGO) cell delivers 3.7 times greater discharge capacity than Li-O2(RGO) cell. Cycling stability of Li-O2 (PPY-RGO) cell is investigated by charge-discharge cycling by limiting the capacity to 1000 mAh g-1, and the cell voltage at the end of discharge and at the end of charge are found constant at 2.75 and 4.10 V, respectively (Fig. 4 a, b). This study shows that PPY-RGO is stable in Li-O2 cells. Electrochemical impedance study shows that charge-transfer resistant is 500 Ω for freshly assembled Li- O2(PPY-RGO) cell and it decreases to 200 Ω after 1st discharge. Synthesis of magnesium cobalt silicate and its electrochemical activity are presented in Chapter 6. MgCoSiO4 is synthesized by mixed solvothermal approach and characterized by various physicochemical techniques. Cubic shaped MgCoSiO4 is investigated for oxygen evolution reaction (OER) activity in alkaline and neutral media. The current values at 0.95 versus SHE are 43, 0.18, 16 mA cm-2 on MgCoSiO4, bare carbon paper and Pt foil electrodes, respectively (Fig. 5), indicating that MgCoSiO4 is a good catalyst for OER. The onset potential for OER is 0.68 V versus SHE on MgCoSiO4 in 1 M KOH. OER activity on MgCoSiO4 is also studied in K2SO4 and phosphate buffer electrolytes. The results indicate good catalytic activity of MgCoSiO4 in neutral electrolytes also. The catalytic activity of Fig. 5. Cyclic voltammograms of bare carbon paper (i), Pt foil (ii), MgCoSiO4 coated carbon (iii) electrodes in 1 M KOH (sweep rate = 5 mV s-1, loading level = 1.15 mg, area = 0.5 cm-2). MgCoSiO4 towards ORR in aqueous and non-aqueous electrolytes is studied by RDE experiments. Li-O2 cells are assembled with bifunctional MgCoSiO4 catalyst in 1 M LiPF6- DMSO electrolyte and the discharge capacity values obtained are 7721 (8.27), 2510 (1.66) and 1053 mAh g-1 (0.92 mAh cm-2) when discharged at 0.3, 0.5 and 0.8 mA cm-2 current densities, respectively. Electrochemical impedance spectroscopy (EIS) measurements of LiMn2O4 electrode are carried out at different temperatures from -10 to 50 0C and in the potential range from 3.50 to 4.30 V, and the data are analysed in Chapter 7. In the EIS spectra recorded over the frequency range from 100 kHz to 0.01 Hz at different temperatures, there are two semicircles present in the Nyquist plot (Fig. 6a). But in 3.90 to 4.10 V versus Li/Li+(1M) potential range at low temperatures (-10 to 15 oC) range, another semicircle also appears (Fig. 6b). Impedance parameters such as solution resistant (Rs), charge-transfer resistance (Rct), doublelayer capacitance (Cdl), electronic resistance (Re) and Warburg impedance (WR), etc., are obtained by analysis of the EIS data. The variations of resistances with temperature are analysed by Arrhenius-like relationships and the apparent activation energies of the corresponding transport properties are evaluated. The values of activation energy for chargetransfer process are 0.37, 0.30 and 0.42 eV, at 3.50, 3.90 and 4.10 V versus Li/Li+(1M), respectively. The chemical diffusion coefficient of Li+ ions into LiMn2O4 calculated from EIS data. The values of diffusion coefficient calculated are in the range of 2.50 x 10-12 - 4.10 Fig. 6. Nyquist plot of impedance study of Li/LiMn2O4 cell at 3.50 V (a) and 3.90 V (b) at -10 0C. Details of the above studies are described in the thesis.

A utilização de conversores multiníveis tem sido uma importante alternativa para aplicações de alta potência e média tensão, graças aos altos níveis de potência alcançáveis por estas estruturas. Recentemente, esta topologia de conversores foi aplicada em sistemas com fontes alternativas para alimentar um sistema de geração distribuída, nos quais diferentes fontes de energia eram utilizadas. Com base nas características dos conversores multinível e sua potencial aplicabilidade em sistemas de geração distribuída, este trabalho tem como objetivo construir um sistema multinível conectado a rede de distribuição para utilização de fontes alternativas de energia como fontes primárias. Considerando que a energia fornecida pelas fontes alternativas pode sofrer variações, propõe-se a integração de sistemas armazenadores de energia, como capacitores, ao sistema multinível. Por isso, este trabalho desenvolve uma estratégia de controle para máxima transferência de potência ativa entregue à rede a fim de obter um fluxo ótimo. A topologia multinível deste trabalho possui em sua configuração dois módulos inversores conectados em série. Neste caso, é possível que pelo menos um desses inversores funcione com uma modulação em baixa frequência processando a maior parcela de potência. Assim, duas estratégias de controle modulação de fase e modulação de amplitude para a transferência de potência realizada pelo inversor de baixa frequência são analisadas. As vantagens e desvantagens de cada um dos métodos são expostas e então a estratégia mais adequada, no caso a modulação de amplitude, é utilizada na operação do conversor multinível. Além disso, são apresentados a modelagem das plantas e o projeto dos controladores de cada um dos módulos inversores. Por fim, a validação da proposta é feita através dos resultados de simulações e experimentais que mostram a capacidade do sistema de geração em transferir potência constante para a rede de distribuição e manter a corrente quase sem distorções em fase com a tensão. / The utilization of multilevel converters has been an important alternative for medium voltage applications with high power and power quality demand, thanks to the high power levels achievable for this kind of structure. Recently, this converter topology was proposed as a new possibility in renewable energy source applications, mainly in system delivering power to the grid, where different renewable energy resources may be used. Based on the characteristics of multilevel converters, and their potential applicability in distributed generation systems, this study aims to build a multilevel system that could be powered by renewable energy sources as primary sources and then connect them to a distribution grid. However, considering the energy produced by alternative sources can vary, it is analyzed the integration of a storage energy system in this multilevel topology. Taking into account this ends, the main concern of this study is related to the development of a control strategy to maximize the active power transferred to the grid. The multilevel topology employed in this study has two H-bridge inverter modules connected in series forming a cascaded configuration. Therefore, it is possible that at least one of these inverters, operating with a low frequency of modulation, process the majority of power with lower amount of losses. On this way, two control strategies for power transfer are analyzed. The advantages and disadvantages of each method are presented, and the most appropriated strategy is used in the operation of the multilevel converter system. In addition, it has been presented the design criteria for each controller and finally the validation of the proposed approach is done by mains of simulations and experimental results which show the ability of the converter to transfer constant active power to the grid and keep the grid current in phase with the grid voltage.

Autonomic management is important in storage systems and the space of autonomics in storage systems is vast. Such autonomic management systems can employ a variety of techniques depending upon the specific problem. In this thesis, we first take an algorithmic approach towards reliability enhancement and then we use learning along with a reactive framework to facilitate storage optimization for applications. We study how the reliability of non-repairable systems can be improved through automatic reconfiguration of their XOR-coded structure. To this regard we propose to increase the fault tolerance of non-repairable systems by reorganizing the system, after a failure is detected, to a new XOR-code with a better fault tolerance. As errors can manifest during reorganization due to whole reads of multiple submodules, our framework takes them in to account and models such errors as based on access intensity (ie.BER-biterrorrate). We present and evaluate the reliability of an example storage system with and without reorganization. Motivated by the critical need for automating various aspects of data management in virtualized data centers, we study the specific problem of automatically implementing Virtual Machine (VM) migration in a dynamic environment according to some pre-set policies. This is a problem that requires automated identification of various workloads and their execution environments running inside virtual machines in a non-intrusive manner. To this end we propose AuM (for Autonomous Manager) that has the capability to learn workloads by aggregating variety of information obtained from network traces of storage protocols. We use state of the art Machine Learning tools, namely Multiple Kernel learning ,to aggregate information and show that AuM is indeed very accurate in identifying work loads, their execution environments and is also successful in following user set policies very closely for the VM migration tasks. Storage infrastructure in large-scale cloud data center environments must support applications with diverse, time-varying data access patterns while observing the quality of service. To meet service level requirements in such heterogeneous application phases, storage management needs to be phase-aware and adaptive ,i.e. ,identify specific storage access patterns of applications as they occur and customize their handling accordingly. We build LoadIQ, an online application phase detector for networked (file and block) storage systems. In a live deployment , LoadIQ analyzes traces and emits phase labels learnt online. Such labels could be used to generate alerts or to trigger phase-specific system tuning.

An ever-decreasing cost of photovoltaics (PV) combined with generous installation subsidies lead to a growth of PV systems in Sweden. A large-scale penetration of PV power would make Energy Storage Systems (ESS) interesting for providing back-up storage, enabling flexibility and regulating intermittence. ESS represents a vital link between electrical supply and demand, and moreover a critical feature for increasing the use and attractiveness of renewable and intermittent energy sources. The purpose of this study is to do a quantitative analysis examining the most beneficial way to store electricity from PV regarding investment cost, life span, capacity and pay-off time. The study object is Valsätraskolan, a school in Uppsala with an existing PV system. The thesis shows that Lithium-ion batteries are the best prospected battery type but still not an economically profitable investment. With the current grid- and battery prices the most suitable battery solution has a pay-off time of 125 years. If the school would extend their PV system to cover all preferable roof areas, the pay-off time would be 48 years. If ESS are to become attractive from a financial point of view, the grid prices would have to increase and the cost for ESS decrease substantially.

Web designers are expected to perform the difficult task of adapting a site’s design to fit changing usage trends. Web analytics tools give designers a window into website usage patterns, but they must be analyzed and applied to a website's user interface design manually. A framework for marrying live analytics data with user interface design could allow for interfaces that adapt dynamically to usage patterns, with little or no action from the designers. The goal of this research is to create a framework that utilizes web analytics data to automatically update and enhance web user interfaces. In this research, we present a solution for extracting analytics data via web services from Google Analytics and transforming them into reporting data that will inform user interface improvements. Once data are extracted and summarized, we expose the summarized reports via our own web services in a form that can be used by our client side User Interface (UI) framework. This client side framework will dynamically update the content and navigation on the page to reflect the data mined from the web usage reports. The resulting system will react to changing usage patterns of a website and update the user interface accordingly. We evaluated our framework by assigning navigation tasks to users on the UNF website and measuring the time it took them to complete those tasks, one group with our framework enabled, and one group using the original website. We found that the group that used the modified version of the site with our framework enabled was able to navigate the site more quickly and effectively.

There is currently considerable enthusiasm around the MapReduce paradigm, and the distributed computing paradigm for analysis of large volumes of data. The Apache Hadoop is the most popular open source implementation of MapReduce model and LINQ to HPC is Microsoft's alternative to open source Hadoop. In this thesis, the performance of LINQ to HPC and Hadoop are compared using different benchmarks. To this end, we identified four benchmarks (Grep, Word Count, Read and Write) that we have run on LINQ to HPC as well as on Hadoop. For each benchmark, we measured each system’s performance metrics (Execution Time, Average CPU utilization and Average Memory utilization) for various degrees of parallelism on clusters of different sizes. Results revealed some interesting trade-offs. For example, LINQ to HPC performed better on three out of the four benchmarks (Grep, Read and Write), whereas Hadoop performed better on the Word Count benchmark. While more research that is extensive has focused on Hadoop, there are not many references to similar research on the LINQ to HPC platform, which is slowly evolving during the writing of this thesis.

Sweden has experienced a significant increase in installed solar power capacity between 2010 and 2020, driven by decreasing installation costs, government subsidies and widespread public interest. However, Sweden's geographical distribution of electricity generation and consumption presents challenges for the national grid. Recent instability in the electricity supply due to the war in Ukraine has prompted increased interest in residential battery energy storage systems (BESS) as a means to enhance energy resilience and reduce electricity bills. The rapid growth of the European residential BESS market is expected to continue, driven by the need for flexibility and energy-shifting services in response to increasing renewable energy production. BESS can provide economic benefits to households with installed PV systems through peak shaving, allowing them to store excess electricity during periods of high production and use it during peak demand. This thesis investigates photovoltaic (PV) and BESS performance and profitability for Swedish households under various conditions. The study considers parameters such as system costs, energy prices, grid tariffs and dynamic battery management strategies to investigate the profitability of the systems. The research aims to provide guidelines for households to maximize the benefits of their PV and BESS installations and minimize their dependence on the grid. The effectiveness and practicality of the developed method are demonstrated through verification in two real-world installations. The study’s findings demonstrate that electricity prices, household consumption and roof orientation highly influence the profitability of PV systems. If future electricity prices align with present forecasts, installations on north-facing roofs will not be profitable under any circumstances investigated in this study. A distinct correlation is also discernible between larger loads and improved economic viability for PV and BESS installations, while a smaller battery capacity results in higher economic viability. This reveals that BESS profitability currently is limited due to high installation costs. However, the potential for future BESS profitability is shown if battery costs are reduced and more advanced battery dispatch strategies are developed. / Sverige har upplevt en betydande ökning av installerad solkraftskapacitet mellan åren 2010 och 2020, drivet av faktorer som minskande installationskostnader, statliga bidrag och ett brett folkligt intresse. Geografiska skillnader mellan elproduktion och konsumtion i Sverige innebär utmaningar för elnätet. Instabilitet i elförsörjningen till följd av kriget i Ukraina har ökat intresset för batterilagringssystem i bostäder som ett medel för hushåll att öka deras energiresiliens och minska elkostnaderna. Den snabba tillväxten på den europeiska marknaden för batterilagringssystem förväntas fortsätta, drivet av behovet av flexibilitet i elnätet och energiomställningstjänster till följd av ökad produktion av förnybar energi. Batterilagringssystem kan ge ekonomiska fördelar för hushåll med installerade PV-system genom utjämning av effekttoppar, vilket gör att överskottsenergi kan lagras under perioder av hög produktion och användas under toppbelastning. Denna rapport undersöker prestanda och lönsamhet för solcells- och batterisystem för svenska hushåll under olika förhållanden. Studien utforskar betydande parametrar såsom systemkostnader, energipriser, nättariffer och dynamiska batterihanteringsstrategier för att undersöka lönsamheten för systemen. Detta ämnar till att ge riktlinjer för hushåll att maximera fördelarna med solcells- och batteri-installationer och minimera dess beroende av elnätet. Effektiviteten och praktikaliteten av den utvecklade metoden demonstreras genom verifiering i två verkliga installationer. Resultaten visar atta elpriser, hushållsförbrukning och takorientering i hög grad påverkar lönsamheten hos solcellsanläggningar. Om framtida elpriser stämmer överens med nuvarande prognoser kommer installationer på tak mot norr inte att vara lönsamma under några omständigheter som undersökts i denna studie. En tydlig korrelation kan också urskiljas mellan större elkonsumtion och förbättrad ekonomisk lönsamhet för PV och batteri-installationer, medan en mindre batterikapacitet resulterar i högre ekonomisk lönsamhet. Detta visar att batteriers lönsamhet för närvarande är begränsad på grund av höga installationskostnader. Potentialen för framtida lönsamhet för batterier visas dock om batterikostnaderna sänks och mer avancerade batterihanteringsstrategier utvecklas.