The demand for electricity is rising rapidly, with more power generated through re-newable energy sources. Renewable energy sources can fluctuate in their power output atshort notice, making it more difficult to maintain the balance between electricity consump-tion and production in the short term. A solution that has gained increased interest recentlyis to connect battery energy storage systems to the grid as a means of maintaining balance.However, such systems are often controlled remotely by a cloud control system, creatingtime-critical control loops over the internet that are partly responsible for the stability andcontinued function of the electrical grid. Cyberattacks against these closed-loop systemscould devastate the electrical grid and the apparatus connected to it.In this thesis, a reference model is designed for an electrical grid load-balancing cloudcontrol system connected to remote battery energy storage systems and remote grid fre-quency sensors (measuring the balance between production and consumption). The modelis evaluated from a cybersecurity perspective by implementing a simulator and applyingdifferent cyberattacks on the simulated system.The results show that some of the most critical attack methods that a threat actor couldutilize are: disrupting the connections over the internet that are part of the closed-loopsystem, abusing remote access links from the outside to gain access to subsystems (suchas seizing control of batteries), or disturbing external dependencies to the cloud such asdomain name system (DNS) and network time protocol (NTP) servers or the contractsrelated to electricity trading. The most important cyberattacks identified in the thesis are:time delay switch (delays of messages), denial of service (disturbing message availability),false data injection (modifying message contents), replay (replaying old messages), andload altering (affecting the grid balance through direct altering of electricity consumptionand production).The simulated cyberattacks differ in how they affect the grid frequency, i.e. the gridproduction-consumption balance. Large enough network packet delays caused oscilla-tions in the simulated frequency. Denial of service attacks caused unpredictable behavior,and a high enough packet drop rate caused oscillations. For false data injection, the re-sults depend on which internet link was attacked and what injection strategy was used;some attacks caused oscillations, while others caused a steady state error or even an in-creasingly deviating frequency. Replay attacks were able to cause a deviation during thereplay window when used effectively. Finally, large enough load altering caused oscilla-tions, especially when an attacker had control over at least 15% of the system’s balancingpower.Overall, attacks on the simulated system are serious and precautions must be carefullyconsidered before such a system is implemented in the real world.

Reliability modelling of RAID storage systems with its various components such as RAID controllers, enclosures, expanders, interconnects and disks is important from a storage system designer's point of view. A model that can express all the failure characteristics of the whole RAID storage system can be used to evaluate design choices, perform cost reliability trade-offs and conduct sensitivity analyses. We present a reliability model for RAID storage systems where we try to model all the components as accurately as possible. We use several state-space reduction techniques, such as aggregating all in-series components and hierarchical decomposition, to reduce the size of our model. To automate computation of reliability, we use the PRISM model checker as a CTMC solver where appropriate. Initially, we assume a simple 3-state disk reliability model with independent disk failures. Later, we assume a Weibull model for the disks; we also consider a correlated disk failure model to check correspondence with the field data available. For all other components in the system, we assume exponential failure distribution. To use the CTMC solver, we approximate the Weibull distribution for a disk using sum of exponentials and we first confirm that this model gives results that are in reasonably good agreement with those from the sequential Monte Carlo simulation methods for RAID disk subsystems. Next, our model for whole RAID storage systems (that includes, for example, disks, expanders, enclosures) uses Weibull distributions and, where appropriate, correlated failure modes for disks, and exponential distributions with independent failure modes for all other components. Since the CTMC solver cannot handle the size of the resulting models, we solve such models using hierarchical decomposition technique. We are able to model fairly large configurations with upto 600 disks using this model. We can use such reasonably complete models to conduct several "what-if" analyses for many RAID storage systems of interest. Our results show that, depending on the configuration, spanning a RAID group across enclosures may increase or decrease reliability. Another key finding from our model results is that redundancy mechanisms such as multipathing is beneficial only if a single failure of some other component does not cause data inaccessibility of a whole RAID group.

Detta examensarbete utreder den tekniska och ekonomiska passbarheten av batterilagringssystem (BESS) inom den svenska el infrastrukturen. Syftet är att konstruera tre olika affärsfall för att representera den tekniska och den ekonomiska passbarheten av BESS inom den svenska el infrastrukturen, specifikt med uppkoppling mot distributionsnätverket på den regionala nivån, 6 kilovolt till 132 kilovolt (kV). Affärsfallen adresserar dem tekniska funktioner och kunder inom infrastrukturen som utifrån en litteraturstudie anses vara dem mest attraktiva att bygga ett affärsfall utifrån. Litteraturstudien utreder den svenska el infrastrukturens struktur samt dess existerande och uppkommande utmaningar. Studien utforskar även hela spektrumet energilagringssystem (ESS) för att rättfärdiga valet av litium-jon BESS. Litium-jon BESS är närmare undersökt, där systemets operativa parametrar samt komponenter är kartlagda. Vidare undersöks dem tekniska funktionernas tekniska krav och ekonomiska incitament i en marknadsanalys. Slutligen utforskas regler och lagar omkring BESS implementering i den svenska el infrastrukturen samt placeringen och de kostnader för att bygga en BESS anläggning. De tre affärfallen som är konstruerade i denna studie är: Kombinationen av frekvensrelaterade nätverksstödtjänster för en fristående BESS-tillgångsoperatör. Avbrottsfri strömtillförsel för ett datacenter. Skala effekttoppar och kombination av frekvensrelaterade nätverksstöddtjänster för en industri. Litium-jon BESS anses vara den mest tillämpliga tekniken på grund av dess snabba responstid, höga effekt- och energidensitet samt skalbarheten för att passa majoriteten av de tekniska funktioner som undersökts inom studien. Affärsfallens ekonomiska passbarhet utvärderas efter två ekonomiska indikatorer, nuvärdesberäkning (NPV) samt återbetalningstiden. Affärsfall nummer tvås tekniska funktion erbjuder ingen möjlighet att generera en inkomst vilket gör att den kommer bli utvärderad efter kostnad för service, där utgifterna är uppdelade utöver projektets livstid genom linjär amortering. Vidare används linjär amortering för att räkna ut kostnaden per kilo sparat CO2 utöver livstiden på projektet. Både affärsfall 1 (NPV= 231,0 MSEK, återbetalningstid= 7,8 år) samt affärsfall 3 (NPV= 17,3 MSEK, återbetalningstid= 8,8 år) visar en lönsamhet där affärsfall 2 ger en kostnad för service mellan 5,4 och 5,8 MSEK/år och där kostnaden per sparat kilo CO2 mellan 20,9 och 22,7 SEK/kg CO2. Denna studie fokuserar på de tre största distributionsnätverksoperatorerna (DNO) inom distributionsnätverket på en regional nivå: Vattenfall, Eon och Ellevio. Lönsamheten av de undersökta affärsfallen är starkt kopplade till placeringsområde inom nätverket, spänningsnivån och typ av DNO. Möjlighet att koppla upp BESS till en existerande transformatorstation på anläggningen för affärsfall två och tre minskar investeringskostnaden samt driftkostnaderna vilket vidare förbättrar dess lönsamhet. Affärsfall ett behöver gå igenom en noggrann bedömning för att försäkra sig om lönsamheten. NPV samt återbetalningstiden kan påverkas i affärsfall ett och tre på grund av den ständigt förändrande frekvensregleringsmarknaden där priserna är volatila på grund av nya marknadsinitiativ. Att konstruera ett BESS affärsfall medför att flertalet osäkerheter bör räknas in, såsom de ekonomiska incitamenten som inte visar någon garanti på att vara fortsatt lönsamt. Det höga priset på litium-jon batterier saktar ner attraktiviteten av affärsfallen och måste vidare sjunka för att främja ett lönsamt affärsfall. Andra ESS som flödesbatterier och vätgaslagringssystem visar god passbarhet att bli implementerad i den svenska el infrastrukturen men måste vidare utveckla sin tekniska och kommersiella mognadsgrad innan dem kan vara konkurrenskraftiga med litium-jon BESS.  Examensarbetet är utfört i samarbete med Omexom Infratek Sverige AB med målet att bidra till en större förståelse av BESS roll i den svenska el infrastrukturen och vidare bidra till att konstruera ett tekniskt erbjudande för Omexom Infratek Sverige AB. / This master thesis investigates the technical and economic feasibility of battery energy storage systems (BESS) in the Swedish electrical infrastructure. The aim is to construct three business cases to represent the technical and economic feasibility of BESS implementation in the Swedish electrical infrastructure in the distribution network on the regional level, 6 kilovolts to 132 kilovolts (kV). The business cases address the technical functions and customers within the infrastructure that is recognized through a literature study to build the most attractive and incentivized business cases from. The literature study investigates the Swedish electrical infrastructure’s structure and its existing and upcoming challenges. It investigates the spectrum of energy storage systems (ESS) to justify the choice of the lithium-ion (Li-ion) BESS. The Li-ion BESS is closer examined, where the systems operational parameters and components are mapped out. Furthermore, the technical functions technical requirements and economic incentives are investigated in a market analysis. Lastly, considerations regarding regulations and permits, the placement of BESS within the infrastructure and its surrounding costs is evaluated. The three business cases that are constructed within the thesis are:  Combination of frequency related grid support services for a standalone BESS asset operator. Uninterruptable power supply for a data center. Peak shaving and a combination of frequency related grid support services for an industrial plant.  The, Li-ion BESS is considered to most applicable technology due its fast response time, high power and energy density and scalability to suit the majority of technical functions investigated in the thesis. The business cases economic feasibility is evaluated after two economic indicators, the net present value (NPV) and the payback period. Business case two’s technical function offers no possible revenues and is evaluated as a cost for service where the expenses is divided throughout the project lifetime through linear amortization and the cost per saved kg CO2 is calculated over the lifetime of the BESS. Both business case 1 (NPV= 231.0 MSEK, payback period= 7.8 years) and case 3 (NPV=17.3 MSEK, payback period= 8.8 years) show profitability where business case 2 gives a cost per service between 5.4 and 5.8 MSEK/year and cost per saved kg CO2 between 20.9 and 22.7 SEK/kg CO2.  This thesis focuses on the three largest distribution network operators (DNO) in the distribution network on a regional level: Vattenfall, Eon, and Ellevio. The profitability of the business cases investigated are strongly connected to the location in the network, the voltage connection level, and the type of DNO. Being able to connect to an existing substation on site as for business cases 2 and 3 will lower the capital and operational costs and further improve the profitability. Business case 1 needs a thorough assessment of placement in the electrical infrastructure in Sweden to assure profitability. The NPV and payback period in business cases 1 and 3 could conflict with the interchanging frequency regulation market where prices are rather volatile due to new market initiatives. Therefore, looking forward, building a BESS business case to be implemented comes with lots of uncertainties as the economic incentives shows no guarantee to continuously be profitable. The high price of Li-ion batteries is slowing down the attractiveness of the business cases and need to further decrease to promote profitable business cases. Other ESS technologies as flow batteries and hydrogen storage systems show good applicability to be implemented in the Swedish electrical infrastructure but needs to develop its technical and commercial maturity until it can become competitive with Li-ion BESS.  The master thesis is performed in conjunction with Omexom Infratek Sverige AB with the aim to contribute to a broader understanding of the role of BESS in the Swedish electrical infrastructure and to help building BESS technical offers for Omexom Infratek Sverige AB.

Cloud computing and cloud storage services, in particular, pose a new challenge to digital forensic investigations. Currently, evidence acquisition for such services still follows the traditional approach of collecting artifacts on a client device. In this work, we show that such an approach not only requires upfront substantial investment in reverse engineering each service, but is also inherently incomplete as it misses prior versions of the artifacts, as well as cloud-only artifacts that do not have standard serialized representations on the client. In this work, we introduce the concept of API-based evidence acquisition for cloud services, which addresses these concerns by utilizing the officially supported API of the service. To demonstrate the utility of this approach, we present a proof-of-concept acquisition tool, kumodd, which can acquire evidence from four major cloud storage providers: Google Drive, Microsoft One, Dropbox, and Box. The implementation provides both command-line and web user interfaces, and can be readily incorporated into established forensic processes.

In recent years, power systems are facing with various challenges arising from the increased share of renewable energy systems. Among all sections of power systems, distribution grids are affected the most since the majority of renewable energy sources are connected to distribution grids. As the penetration of Variable Energy Sources increases in electric grids, energy storage systems have become more influential. In this context, this thesis presents a new algorithm for the optimal operation of Battery Energy Storage Systems in distribution grids. The proposed algorithm aims to define the optimal operation of Battery Energy Storage Systems considering the network topology, the output power of Variable Energy Sources and the electricity prices from the one-day ahead electric market as well as real time control of the batteries through smart appliances. In order to do this, firstly a comprehensive study on the existing Optimal Power Flow methods is carried out. Then, AR-OPF which is a novel Optimal Power Flow method for radial distribution systems is presented and the required mathematical constraints, equations and parameters of Battery Energy Storage Systems for modelling in distribution systems are described. Then, the problem formulation and the proposed algorithm are discussed in detail. Further to energy storage as the main function of Battery Energy Storage Systems, the impact of the proposed method on other functions of Battery Energy Storage Systems such as voltage control, grid support and loss reduction will be investigated. In order to do so, the proposed algorithm is applied to the IEEE 34 node test system as a case study. This will be carried out through defining several different scenarios. Finally, a sensitivity analysis is performed on the size of the existing batteries and the electricity price. The thesis will be concluded by the findings and possible future works.

Considering the significant investment of higher education made by students and their families, graduating in a timely manner is of the utmost importance. Delay attributed to drop out or the retaking of a course adds cost and negatively affects a student’s academic progression. Considering this, it becomes paramount for institutions to focus on student success in relation to term scheduling. Often overlooked, complexity of a course schedule may be one of the most important factors in whether or not a student successfully completes his or her degree. More often than not students entering an institution as a first time full time (FSFT) freshman follow the advised and published schedule given by administrators. Providing the optimal schedule that gives the student the highest probability of success is critical. In efforts to create this optimal schedule, this thesis introduces a novel optimization algorithm with the objective to separate courses which when taken together hurt students’ pass rates. Inversely, we combine synergistic relationships that improve a students probability for success when the courses are taken in the same semester. Using actual student data at the University of Kentucky, we categorically find these positive and negative combinations by analyzing recorded pass rates. Using Julia language on top of the Gurobi solver, we solve for the optimal degree plan of a student in the electrical engineering program using a linear and non-linear multi-objective optimization. A user interface is created for administrators to optimize their curricula at main.optimizeplans.com.

Daktaro disertacijoje tyrinėjamos vėjo elektrinių balansavimo galimybės panaudojant energijos kaupimo sistemas ir sprendžiamas balansavimo galių valdymo uždavinys. Darbo metu buvo ištirta vėjo elektrinių prognozavimo paklaidų įtaka balansavimo galioms, sudaryti balansavimo galių valdymo ir energijos kaupimo sistemų dinaminiai modeliai ir nustatyti tokių sistemų parametrai vėjo elektrinių galių subalansavimui atsižvelgiant į valdymo signalo kitimo greitį ir balansuojančių elektrinių galios keitimo spartą. Darbo išvados ir sukaupta informacija yra reikšminga integruojant energijos kaupimo sistemas į automatinio generavimo valdymo sistemos darbą. Pasiūlyti sprendimai leidžia tiksliau nustatyti reguliavimo rezervo apimtis bei pagerinti sistemos režimo parametrų valdymo kokybę. / Wind power balancing using energy storage systems as well as balancing control strategies are investigated in the thesis. The wind power balancing options are expanded by proposed dynamic models according to control signal rate of change and power plants ramp rates. The influence of wind power forecasting errors to regulating power reserve was investigated. The required energy storage system parameters for wind power balancing were determined and the regulation intensity of conventional power plants was reduced. The results obtained in the thesis are useful for energy storage systems integration into the central automatic generation control system. The solutions proposed let to increase the determination accuracy of regulating active power reserves and improve the quality of the system control parameters.

The increasing amount of available semistructured data demands efficient mechanisms to store, process, and search an enormous corpus of data to encourage its global adoption. Current techniques to store semistructured documents either map them to relational databases, or use a combination of flat files and indexes. These two approaches result in a mismatch between the tree-structure of semistructured data and the access characteristics of the underlying storage devices. Furthermore, the inefficiency of XML parsing methods has slowed down the large-scale adoption of XML into actual system implementations. The recent development of lazy parsing techniques is a major step towards improving this situation, but lazy parsers still have significant drawbacks that undermine the massive adoption of XML. Once the processing (storage and parsing) issues for semistructured data have been addressed, another key challenge to leverage semistructured data is to perform effective information discovery on such data. Previous works have addressed this problem in a generic (i.e. domain independent) way, but this process can be improved if knowledge about the specific domain is taken into consideration. This dissertation had two general goals: The first goal was to devise novel techniques to efficiently store and process semistructured documents. This goal had two specific aims: We proposed a method for storing semistructured documents that maps the physical characteristics of the documents to the geometrical layout of hard drives. We developed a Double-Lazy Parser for semistructured documents which introduces lazy behavior in both the pre-parsing and progressive parsing phases of the standard Document Object Model's parsing mechanism. The second goal was to construct a user-friendly and efficient engine for performing Information Discovery over domain-specific semistructured documents. This goal also had two aims: We presented a framework that exploits the domain-specific knowledge to improve the quality of the information discovery process by incorporating domain ontologies. We also proposed meaningful evaluation metrics to compare the results of search systems over semistructured documents.

The purpose of this project is to design, build, and implement an information retrieval database system for the Accounting Department at CSUSB. The database will focus on the financial details of the student accounts maintained by the accounting personnel. It offers detailed information pertinent to tuition, parking, housing, boarding, etc.

Computing researchers have long focused on improving energy-efficiency?the amount of computation per joule? under the implicit assumption that all energy is created equal. Energy however is not created equal: its cost and carbon footprint fluctuates over time due to a variety of factors. These fluctuations are expected to in- tensify as renewable penetration increases. Thus in my work I introduce energy-agility a design concept for a platform?s ability to rapidly and efficiently adapt to such power fluctuations. I then introduce a representative application to assess energy-agility for the type of long-running, parallel, data-intensive tasks that are both common in data centers and most amenable to delays from variations in available power. Multiple variants of the application are implemented to illustrate the fundamental tradeoffs in designing energy-agile parallel applications. I find that with inactive power state transition latencies of up to 15 seconds, a design that regularly ”blinks” servers out- performs one that minimizes transitions by only changing power states when power varies. While the latter approach has much lower transition overhead, it requires additional I/O, since servers are not always concurrently active. Unfortunately, I find that most server-class platforms today are not energy-agile: they have transition la- tencies beyond one minute, forcing them to minimize transition and incur additional I/O.