A linear programming model has been developed for a Central Energy Plant which minimizes operational costs for a system involving the generation of chilled water and high temperature hot water plus the generation and/or purchase of electric power with equipment using natural gas or fuel oil energy. The fundamental concepts developed herein are sufficient for the analysis of any combination of energy supplies, demands, and energy conversion equipment. Utilization of this model is demonstrated with a case study and computer program results for high and low temperature environments. The linear programming model approach establishes a well-defined framework for the analysis of complex utility systems and provides valuable results for the economical operation of a Central Energy Plant.

Detta examensarbete undersöker operationssjuksköterskans erfarenheter av att upprätthålla patientsäkerhet under en operation. Operationssjuksköterskan ansvarar för flera viktiga aspekter såsom hygien, medicintekniska produkter, instrumentering, ledarskap och kommunikation. Hen måste även kunna etablera en trygg och individanpassad interaktion med patienterna. Statistik visar att vårdskador och postoperativa sårinfektioner är allvarliga konsekvenser av bristande vårdkvalitet och patientsäkerhet, och dessa förekommer i hög utsträckning. Det finns dock en potential att begränsa antalet sårinfektioner genom att följa evidensbaserade riktlinjer. Genom en litteraturstudie, som följde strikta riktlinjer, har tematisk analys enligt Braun och Clarke (2006) använts för att identifiera, analysera och redovisa mönster och teman i den insamlade datan. Resultaten har lyft fram två huvudteman: ”Samverkan på operationssalen” och ”Strukturella faktorer som påverkar patientsäkerheten”. Dessa teman har belyst de faktorer som påverkar operationssjuksköterskans arbete och dess koppling till patientsäkerhet och vårdkvalitet. Diskussion betonar vikten av effektiva förberedelser, god kommunikation och säkert arbete inom vårdteamet för att uppnå en framgångsrik perioperativ vård och minimera vårdrelaterade skador. Sammanfattningsvis visar resultaten operationssjuksköterskans erfarenheter och dess centrala roll i att skapa en säker och effektiv vårdmiljö under kirurgiska ingrepp. Samtidigt understryks vikten av ett förbättrat samarbete och respekt inom vårdteamet för att förhindra missförstånd och förbättra patientsäkerheten.

This thesis explores the Junta de Coordinación Revolucionaria (JCR) and its impact on the outbreak of political violence in the Southern Cone. Given the JCR's short existence and the barbarity of Operation Condor, most scholars have overlooked this organization or treated as convenient excuse for the military regimes to justify their heinous crimes. This article attempts to transcend the one-dimensional view that has predominated studies on the JCR by exploring its revolutionary project and contextualizing it within the international and domestic context in which it developed. Through the analysis of archival material and secondary sources I argue that the JCR represented a historic union for the region's armed left that merits greater recognition by scholars of Latin America's Cold War. / History

<p> One of the important objectives of a Radar Warning Receiver (RWR) aboard a tactical aircraft is to evaluate the level of threat posed by hostile radars in an extremely complex Electronic Warfare (EW) environment in reliable, robust and timely manner. For the RWR objective to be achieved, it passively collects electromagnetic signals emitted from potentially hostile radars. One class of such radar systems is the Multi-Function Radar (MFR) which presents a serious threat from the stand point of a RWR. MFRs perform multiple functions simultaneously employing complex hierarchical signal architecture. The purpose of this paper is to uncover the evolution of the operational mode (radar function) from the view point of a target carrying the RWR when provided with noisy observations and some prior knowledge about how the observed radar functions. The RWR estimates the radar's threat which is directly dependant on its current mode of operation. This paper presents a grid filter approach to estimate operational mode probabilities accurately with the aid of pre-trained Observable Operator Models (OOMs) and Hidden Markov Models (HMMs). Subsequently, the current mode of operation of a radar is estimated in the maximum a posteriori (MAP) sense. Practicality of this novel approach is tested for an EW scenario in this paper by means of a hypothetical MFR example. Finally, we conclude that the OOM-based grid filter tracks the mode of operation of a MFR more accurately than the corresponding HMM-based grid filter. </p> / Thesis / Master of Applied Science (MASc)

This thesis is largely expository, and we provide a survey on unknotting operations. We examine these local transformations for classical, virtual and welded knots and use their properties to calculate upper bounds on unknotting numbers. In addition, the thesis contains some original work, such as the definition and properties of the algebraic unknotting numbers of virtual and welded knots, an algebraic reformulation of t4-conjecture, and a new method to tell if a knot can be turned into a torus knot with one crossing change. / Thesis / Master of Science (MSc)

No / The dependency of maintenance as a manufacturing logistic function has made the considerations and constrains of maintenance decisions complex in nature. The rapid growth of automation in manufacturing process has also increased the role of maintenance as an inseparable business partner. As consequence, maintenance strategy and operations should always be aligned with business and manufacturing perspectives within a holistic and integrated manner to achieve competitive advantage. This paper presents a framework of Knowledge Based System for Integrated Maintenance Strategy and Operation (KBIMSO) linked to business and manufacturing perspectives. The KBIMSO framework has novelty of simultaneously highlighting the elements of business, manufacturing and maintenance perspectives which contribute to direct maintenance performance and can be used by the companies to evaluate their existing maintenance system in relation to business competitive priorities and manufacturing process requirements in order to gain optimal maintenance performance as the competitive driver. / Support for this study is provided by the Directorate of Higher Education, Ministry of National Education, Republic of Indonesia and the University of Bradford, the United Kingdom. / The full text cannot be displayed due to the publisher's copyright agreement.

The Mekong River Basin (MRB) is one of the largest transboundary basins in the world shared between six south Asian countries. The Mekong river supports a population of more than sixty million people through irrigation and fisheries for their survival and hosts approximately 88,000 MW of unharnessed hydropower potential. The construction of the dams for the supply of energy has a wide-ranging effect on the downstream regions of reservoirs, causing unprecedented and devastating damage to the environment and livelihood of people. The dissertation examines the optimal operation of the dams for the equitable distribution of water between irrigation, domestic, and hydropower sectors with minimal effect on the downstream ecosystem by estimating the cascading effects of dams in the MRB. The hydrological characteristic of the MRB was simulated using the high resolution (1 km) Variable Infiltration Capacity (VIC) hydrological model with the Lohmann et al. (1996, 1998) routing scheme and general circulation models projection for the future till 2099. Remote sensing products were used for the derivation of the reservoir behaviors, while the net irrigation water requirement (NIWR) was simulated by the irrigation scheme embedded in the improved VIC model. The VIC-MODFLOW (VIC-MF) coupled model was used for the investigation of the interaction between the surface and groundwater movement. The hydropower potential of the dams was estimated using the modified Hanasaki et al. (2006) approach by explicitly considering the irrigation water demand from the expanding and intensifying agricultural activities. A system dynamic model for the MRB was developed for the sustainable optimization of water allocation to meet the needs from the irrigation, domestic, hydropower generation, and ecological sectors. Economic analysis was performed to evaluate the existing and future conditions over the resource surplus regions with consideration of social impacts. Streamflows in the MRB varied substantially with the peak monthly streamflow from 10 m3/sec to 40,000 m3/sec. The inflows to dams in both main river and tributaries are projected to increase from 1.2% to 25% under RCP 4.5 and a decrease of 28.5% - 74.7% under RCP 8.5 during 2020-2099 as compared to the historic mean. The NIWR for the MRB was calculated as 65,000 million m3 for the observed period (1981-2019) with a decrease of 0.25% for the future period. The groundwater interaction is expected to enhance the surface streamflow resulting in additional inflow to dams. The multipurpose reservoirs were able to generate the desired annual energy ranging from 15 GWh to 400 GWh along with satisfying more than 80% of the irrigation water demand. Similarly, the irrigation reservoirs also satisfied more than 80% of the water demand for irrigation and hydropower reservoirs to generate the required energy between 2 GWh and 18990 GWh. Climate change will enhance the hydropower potential with an average increase of 7.3% and 5.3% in the future under RCP 4.5 and RCP 8.5, respectively. The increase in the irrigated area (5% and 10%) reduces the energy generation of the multipurpose dams by 1.5%, however, the addition of a crop cycle lowers the energy generation by more than 10%. The system dynamics model showed the multipurpose dams produced annual energy of 316 GWh and satisfied more than 60% of the irrigation, municipal, and industrial sectors water demand during 2006-2019. Similarly, irrigation dams supplying more than 60% of the irrigation water demand, and 50% of the municipal and industrial sectors demand. Climate change has a positive influence on the performance of the dams. The assessment of the shadow price shows that the dam operation in Thailand, Laos PDR, and China will be sufficient to meet the water demands of the energy, irrigation, municipal, and industrial sectors, while the energy sector of Cambodia and Vietnam may experience adverse impacts. / Doctor of Philosophy / The Mekong River Basin (MRB) is one of the largest transboundary basins in the world shared between six south Asian countries. The Mekong river supports more than sixty million people through irrigation and fisheries for their survival and hosts unharnessed hydropower potential. The construction of the dams has a wide-ranging effect on the downstream regions of reservoirs, causing damage to the environment and livelihood of people. The dissertation studies the optimal operation of the dams in the MRB for the equitable distribution of water between irrigation, domestic, and hydropower sectors with minimal effect on the ecosystem. The streamflow of the MRB was simulated using the hydrological model with a routing scheme and future projection till 2099. Remote sensing products were used for the derivation of the reservoir behaviors. The water requirement for the irrigation and the groundwater-surface interaction was simulated by the irrigation scheme embedded in the hydrological model and groundwater coupled model. The hydropower potential of the dams was estimated by explicitly considering the irrigation water demand from the expanding and intensifying agricultural activities. A dynamic model for the MRB was developed for the sustainable optimization of water allocation to meet the needs from the irrigation, domestic, hydropower generation, and ecological sectors. Economic analysis was performed to evaluate the existing and future conditions over the resource surplus regions with consideration of social impacts. Streamflows in the MRB varied substantially between the dams based on the location at the mainstem or tributaries. The inflows to dams in both main river and tributaries in the future is expected to increase under low-carbon emission and decrease under high-carbon emission conditions. The irrigation water for the MRB was calculated as 65,000 million m3 for the period 1981-2019 and expected to decrease in the future. The groundwater interaction is expected to increase the surface streamflow resulting in additional inflow to dams. The multipurpose reservoirs were able to generate the desired annual energy ranging along with satisfying more than 80% of the irrigation water demand. Similarly, the irrigation reservoirs also satisfied more than 80% of the water demand for irrigation and hydropower reservoirs to generate the required energy. Climate change will favor the hydropower energy potential in the future. The increase in the irrigated area and the addition of a crop cycle reduces the energy generation of the multipurpose dams. The system dynamics model showed the multipurpose dams produced 97% of the demand energy and satisfied more than 60% of the irrigation, municipal, and industrial sectors water demand during 2006-2019. Similarly, irrigation dams supplying more than 60% of the irrigation water demand, and 50% of the municipal and industrial sectors demand. Climate change has a positive influence on the performance of the dams. The assessment of the shadow price shows that the dam operation in Thailand, Laos PDR, and China will be sufficient to meet the water demands of the energy, irrigation, municipal, and industrial sectors, while the energy sector of Cambodia and Vietnam may experience adverse impacts.

This thesis proposes a complete modeling and control design methodology for a multifunctional single-phase bidirectional PWM converter in renewable energy systems. There is a generic current loop for different modes of operation to ease the transition between different modes, including stand-alone inverter mode, grid-tied inverter mode, grid-tied rectifier mode and grid-tied charger/discharger mode. Under stand-alone mode operation, ac voltage regulation is of importance because of the sensitive loads. In this thesis, different multi-loop-based control schemes are investigated and compared, especially between the load current feedback control, PR control and capacitor current loop control. It shows that PR controller reduces the steady-state error, while load current feedback controller improves the transient response. However, the load current feedback controller and capacitor current loop controller presents unstable outputs under some filter load condition. Single-phase d-q frame control is also studied. In order to ease the implementation effort, an unbalanced d-q frame control is proposed to achieve zero steady-state error voltage regulation without generating β-axis component. Based on the same principle, a d-q frame-based single-phase PLL is also proposed to achieve the fast dynamic response with the zero steady-state error phase tracking. The entire control system is verified on a modified 7 kW single-phase PWM converter prototype with a simple DSP-based digital implementation. The load step response test is presented under different modes of operation. The controllers for stand-alone mode are also done under no load, 1 kW resistive load, 1kVar capacitive load, and non-linear load conditions verifying that the single-phase d-q achieves 70% steady-state error improvement if taking the normal PID controller as the baseline design. In the end, the proposed PLL is compared with the standard PLL by experiments showing that the steady-state error can be reduced by 80%. / Master of Science

Over the past couple decades, the capabilities of battery-powered electronics has expanded dramatically. What started out as large bulky 2-way radios, wristwatches, and simple pacemakers, has evolved into pocket sized smart-phones, digital cameras, person digital assistants, and implantable biomedical chips that can restore hearing and prevent heart attacks. With this increase in complexity comes an increase in the amount of processing, which runs on a limited energy source such as a battery or scavenged energy. It is therefore desirable to make the hardware as energy efficient as possible. Many battery-powered systems require digital signal processing, which often makes up a large portion of the total energy consumption. The digital signal processing of a battery-powered system is therefore a good target for power reduction techniques. One method of reducing the power consumption of digital signal processing is to operate the circuit in the subthreshold region, where the supply voltage is lower than the threshold voltage of the transistors. Subthreshold operation greatly reduces the power and energy consumption, but also decreases the maximum operating frequency. Many digital signal processing applications have real-time throughput requirements, so various architectural level techniques, such as pipelining and parallelism, must be used in order to achieve the required performance. This thesis investigates the use of parallelization and subthreshold operation to lower the power consumption of digital signal processing applications, while still meeting throughput requirements. Using an off the shelf fast fourier transform architecture, it will be shown that through parallelization and subthreshold operation, a 70% reduction in power consumption can be achieved, all while matching the performance of a nominal voltage single core architecture. Even better results can be obtained when an architecture is specifically designed for subthreshold operation. A novel Discrete Wavelet Transform architecture is presented that is designed to eliminate the need for memory banks, and a power reduction of 26x is achieved compared to a reference nominal voltage architecture that uses memory banks. Issues such as serial to parallel data distribution, dynamic throughput scaling, and memory usage are also explored in this thesis. Finally, voltage scaling greatly increases the design space, so power and timing analysis can be very slow due long SPICE simulation times. A simulation framework is presented that can characterize subthreshold circuits accurately using only fast gate level design automation tools. / Master of Science

Twenty-four independent logging businesses in the Southeastern United States were analyzed in a general systems approach to document the components of logging costs for mechanized operations, assess the sensitivity of these components to external stimuli, and to identify and describe the business management techniques adopted by contractors to insure survival and profitability. The contractors' cost records for 1988 and 1989 were analyzed to meet the study's first two objectives and interviews with each participant facilitated identification of survival and profitability strategies. The general interviews and on-site observations of the harvesting systems provided background information for evaluating the costs and identifying business management techniques. The contractors' records were summarized into six cost components: 1) consumable supplies, 2) labor, 3) equipment,4) insurance. 5) contract hauling, and 6) administrative overhead. Contractors were stratified by trucking strategy, ranging from those who hauled all of their own wood to contractors relying exclusively on contract truckers. Consumable supplies, labor, and equipment accounted for approximately 75% of total costs for the average contractor in 1988 and 1989. The concept of excess logging capacity was evaluated. Analyses indicate that excess capacity exists in many areas of the Southeastern U.S., and excess capacity influences cost structures and survival strategies. Discussion with most contractors and evaluation of direct costs of excess capacity indicated that contractors are unable to achieve marginal efficiencies due to the large number of suppliers in some areas. Four major business survival strategies were identified during the study. Equity dissolution and diversification were the prevalent strategies, suggesting that the late 1980s and early 1990s favor harvesting systems that are downwardly elastic in terms of production. / Master of Science