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1
Su, Wencong. "Microgrid Modeling, Planning and Operation." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35843.
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As distributed generations and renewable energy are becoming the fastest growing segment of the energy industry, the technical issues and environmental impacts have to be studied and understood. The large number of small-scale Microgrid components with their own characteristics is a big challenge for Microgrid modeling, simulation, planning and operation.
The major goal of this thesis is to build a library of various Microgrid components. First of all, the thesis is going to present a detailed description of Microgrid models with moderate complexity. Next, it will present the modeling of loads, utility grid and transmission lines. Then, the paper will discuss the distributed generation models that have been developed in Matlab/Simulink including Diesel Engine, Fuel Cell, Micro Gas Turbine, Wind Turbine, Photovoltaic Cell, along with the detailed modeling of short-term storage (Battery, Pumped Hydro Storage, Flywheel, and Supercapacitor). In addition to steady-state study, the thesis will also discuss the hybrid sample systems that are built to investigate their transient responses.
To enhance the simulation performance, some improvements on modeling and simulation will be introduced as well. To accommodate the high demand of renewable energy and the environment policy, the planning and operation the of Micro-source generators has been studied using HOMER. Simulation results show a case study of an optimal microgrid configuration on Ontario area in Canada. Sensitivity variables are specified to examine the effect of uncertainties, especially in a long-term planning. Also, demand side management plays an important role in the operation of Microgrid. Based on raw data, case studies are carried out to investigate and validate the demand response methods. Finally, the philosophy for Microgrid protection, especially Time-delay overcurrent protection, will be briefly introduced in both gird-connected and islanding modes.
Master of Science
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Grieg, Thomas Willumsen, Ole Henrik F. Pedersen, and Jørgen Rønholt. "Simulation and Rescheduling of Operation for a RoRo-fleet." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22367.
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This master thesis is a part of the MARFLIX (MARitime FLeet size and mIX) project. The research project MARFLIX is a collaboration between NTNU, MARINTEK, DNV and WWL. The overall aim for the MARFLIX project is to develop and test methods for improved support for fleet size and mix decision-making through quantitative methods. Wallenius Wilhelmsen Logistics (WWL) is a global liner shipping company which delivers shipping and logistics solutions for manufacturers of car, trucks, heavy equipment and specialized cargo. In this master thesis a framework model that is able to test and verify deployment models was developed. This framework model contains a simulation part and an optimization part. The simulation model is constructed to simulate the day to day operations of a fleet. In the day to day operation disruptions will occur. These disruptions are simulated by the use of two different probability distributions and Monte Carlo Simulation. Disruptions occur regularly in a global liner shipping network. About 70-80 % of the vessels experience delays in at least one port during each roundtrip. When a disruption occurs in a liner shipping network, the impact on the network should be minimized.When a disruption occurs, the simulation model will first try to regain the delay by speeding up the delayed vessel. If speeding up is not sufficient, a rescheduling process is initiated. The simulation model will then call on the optimization model to perform a rescheduling. The optimization model considers omitting and changing the order of port calls, and space chartering cargo as possible recovery actions. It will then find the best way to recover from the delay. The new solution will then be implemented as new schedules for the vessels in the fleet.The optimization model is modeled as a set partition model, which can take use of the beneficial structure that appears in transportation problems. To solve a set partition model a column generation algorithm is needed. The column generation algorithm implemented in our model is a complete enumeration algorithm, which generates all possible routes that the vessels can sail. A benefit with the complete enumeration algorithm is that the same routes can be used for all reschedulings during a simulation.There are several incidents, e.g. machinery problems, extreme weather and collision, that can cause delays for a vessel and with that create a need for a rescheduling. Each of these incidents have different impacts on ships, e.g. reduced speed, delayed, changed resistance, port call canceled etc. The simulation and optimization model have been tested on several different problems with a different composition of ports, vessels and cargos. The time required to solve the different test instances varied between 30 and 240 seconds. The tests showed that the required computing time increased exponentially with an increase in the number of ports. The tests also showed that when the chartering cost increased, the number of chartered ships decreased and the rescheduling cost increased.The new routes generated and implemented by the optimization model show similarities with the original routes; in most scenarioes only one or two port calls are changed or left out. This is done contrary to what many shipping companies usually do when they experience delays; they often speed up until the delay is regained.The simulation and optimization models developed in this thesis are able to test and verify the MARFLIX deployment model. In case of a delay the models are able to find good schedules for the fleet within a reasonable amount of time. The different output values provided by the simulation model should be sufficient to verify the deployment model.
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Dalmau, Figueras Montserrat. "Integrated operation of membrane bioreactors: simulation and experimental studies." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/284740.
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Membrane bioreactors (MBR) are a combination of common bioreactors and membrane filtration units for biomass retention, presenting unique advantages like high effluent quality and a smaller footprint than the one by conventional wastewater treatment plants. However, fouling and its associated costs are the main drawbacks related to this technology. This thesis presents a step towards the integrated operation of MBRs through experimental and model-based studies. Interactions between the biological (nutrient removal and sludge characteristics) and physical (hydrodynamics and filtration) processes in MBRs were studied, with the final aim being to improve their integrated operation and control. Moreover, the reduced energy costs and the better understanding of MBR operation may contribute to making MBR systems a more competitive technology to deal with water scarcity problemsEls bioreactors de membranes (BRM) són una combinació dels reactors convencionals i una unitat de filtració que reté la biomassa, de manera que presenten com a gran avantatge una qualitat de sortida amb estàndards de reutilizació, i molt poca necessitat d’espai. Tanmateix, l'embrutiment i els seus costs associats són els principals inconvenients d'aquesta tecnologia. Aquesta tesi presenta un pas endavant cap a l’operació integrada dels BRM mitjançant estudis experimentals i de modelització. Les interaccions entre els processos biològics (eliminació de nutrients i característiques de la biomassa) i físics (hidrodinàmica i filtració) que tenen lloc als BRM s’han estudiat amb l’objectiu final de millorar-ne la seva operació i el control integrat. A més, s'han reduit els costos energètics, els quals contribueixen a la millora de la competitvitat de la tecnologia BRM com a solució potencial per a problemes d’escassetat d’aigua
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Hammond, Alec Michael. "Machine Learning Methods for Nanophotonic Design, Simulation, and Operation." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7131.
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Interest in nanophotonics continues to grow as integrated optics provides an affordable platform for areas like telecommunications, quantum information processing, and biosensing. Designing and characterizing integrated photonics components and circuits, however, remains a major bottleneck. This is especially true when complex circuits or devices are required to study a particular phenomenon.To address this challenge, this work develops and experimentally validates a novel machine learning design framework for nanophotonic devices that is both practical and intuitive. As case studies, artificial neural networks are trained to model strip waveguides, integrated chirped Bragg gratings, and microring resonators using a small number of simple input and output parameters relevant to designers. Once trained, the models significantly decrease the computational cost relative to traditional design methodologies. To illustrate the power of the new design paradigm, both forward and inverse design tools enabled by the new design paradigm are demonstrated. These tools are directly used to design and fabricate several integrated Bragg grating devices and ring resonator filters. The method's predictions match the experimental measurements well and do not require any post-fabrication training adjustments.
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Lizneva, Yulia. "Using simulation method for improving RoPax ship loading operation." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20916.
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Barrowman, Mary Ann McCullen. "Evaluation of operation plans using the Joint Theater Level Simulation." Thesis, Monterey, California. Naval Postgraduate School, 1985. http://hdl.handle.net/10945/21317.
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Sultan, Beshr. "The study of motorway operation using a microscopic simulation model." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322018.
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Wang, Yijia. "HVAC operation uncertainty in energy performance gap." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53858.
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This study aims at a preliminary characterization of system operation uncertainty. It bases this on an analysis of the energy consumption of 6 existing buildings on the Georgia Tech campus. The analysis is speculative in nature.
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Moloney, William J. "Applying simulation techniques to train railway traction drivers." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8370/.
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The writer analyses the introduction of a simulator enabled approach to railway traction driver training and assesses whether the transition from a conventional training delivery process has been effective. The evaluation of effectiveness is based on a study of Iarnród Éireann’s simulator system. Evidence is contained within four supporting strands, i.e., the change in relevant operational risk that has been calculated using ex ante and ex post runs of Iarnród Éireann’s risk model, the internal rate of return on the financial investment necessary to effect the change, the results of an operator attitudinal study and the findings of an independent expert audit. The study establishes that simulation is an effective training medium. The attributes of the system and the use cases that resulted in this finding are described. The writer also presents additional value-adding training objectives that could increase the project’s internal rate of return or IRR. The study affirms that the required verisimilitude of a simulator system is a function of the training goals and the nature of the skills under development. Design features and use strategies can mitigate for potential negative effects of simulator operation. The findings have industry-wide relevance for those tasked with providing effective training to the 133,000 train drivers within the European Union.
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Manataki, Areti. "Analysing supply chain operation dynamics through logic-based modelling and simulation." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7687.
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Supply Chain Management (SCM) is becoming increasingly important in the modern business world. In order to effectively manage and integrate a supply chain (SC), a deep understanding of overall SC operation dynamics is needed. This involves understanding how the decisions, actions and interactions between SC members affect each other, and how these relate to SC performance and SC disruptions. Achieving such an understanding is not an easy task, given the complex and dynamic nature of supply chains. Existing simulation approaches do not provide an explanation of simulation results, while related work on SC disruption analysis studies SC disruptions separately from SC operation and performance. This thesis presents a logic-based approach for modelling, simulating and explaining SC operation that fills these gaps. SC members are modelled as logicbased intelligent agents consisting of a reasoning layer, represented through business rules, a process layer, represented through business processes and a communication layer, represented through communicative actions. The SC operation model is declaratively formalised, and a rule-based specification is provided for the execution semantics of the formal model, thus driving the simulation of SC operation. The choice of a logic-based approach enables the automated generation of explanations about simulated behaviours. SC disruptions are included in the SC operation model, and a causal model is defined, capturing relationships between different types of SC disruptions and low SC performance. This way, explanations can be generated on causal relationships between occurred SC disruptions and low SC performance. This approach was analytically and empirically evaluated with the participation of SCM and business experts. The results indicate the following: Firstly, the approach is useful, as it allows for higher efficiency, correctness and certainty about explanations of SC operation compared to the case of no automated explanation support. Secondly, it improves the understanding of the domain for non-SCM experts with respect to their correctness and efficiency; the correctness improvement is significantly higher compared to the case of no prior explanation system use, without loss of efficiency. Thirdly, the logic-based approach allows for maintainability and reusability with respect to the specification of SC operation input models, the developed simulation system and the developed explanation system.
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Rasmeni, Sibusiso Wiseman. "Simulation of the switched reluctance machine under single pulse mode operation." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53590.
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Thesis (MScEng)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Two distinct simulation methods have been developed to simulate the single and the multi-phase excited current waveforms of the switched reluctance machine (SRM) under single pulse mode operation. These simulation methods are explained and evaluated in this thesis. A non-commercial finite element package that takes the SRM's nonlinear magnetic property into account is used in this regard. The simulation program uses the finite element solution directly during the simulation. Both simulation methods have been investigated in terms of result and total simulation time. In this investigation it is shown how feasible the simulation methods will be with the next generation of fast computers. The factors affecting the simulated current waveforms of the SRM under single pulse mode operation are investigated in detail in this thesis. With these factors taken into account, the measured and simulated multi-phase current waveforms are compared with each other and discussed.
AFRIKAANSE OPSOMMING: Twee verskillende simulasie metodes is ontwikkel om die enkel- en multi-fase stroomgolfvorms van die geskakelde reluktansiemasjien (GRM) onder enkelpulsmodus-werking te simuleer. In hierdie tesis word hierdie simulasie metodes verduidelik en geëvalueer. 'n Nie-kommersiële eindige element pakket wat die nielinieêre magnetiese eienskap van die GRM in ag neem is in hierdie verband gebruik. Die simulasie program gebruik die eindige-element oplossing direk gedurende die simulasie. Beide simulasie metodes is ondersoek in terme van resultaat en simulasietyd. In hierdie ondersoek word getoon hoe uitvoerbaar hierdie tipe simulasie metodes gaan wees met die volgende hoë spoed generasie rekenaars. Die faktore wat die gesimuleerde stroomgolfvorms van die GRM onder enkelpulsmodus-werking beïnvloed word deeglik in hierdie tesis ondersoek. Met hierdie faktore in ag geneem word die gemete en gesimuleerde multi-fase stroomgolfvorms met mekaar vergelyk en bespreek.
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Hogg, Glynn A. "Multi-stem mechanised harvesting operation analysis : application of discrete-event simulation." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1973.
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Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2009.In this study, a multi-stem harvesting operation was observed and time studies carried out on its machines. A stump-to-mill simulation model (System 1) of this system was subsequently built using a commercial simulation software package (Arena 9) and data from the time studies were incorporated into the model. Following this, another two stump-to-mill multistem models (Systems 2 and 3) were built using the same simulation software package and parameterised input data. These two models represented hypothetical systems which were tested against System 1 and against one another in terms of machine balance within the system, production rate and cost. System 2 used identical equipment to System 1, but practised alternative operating methods. Some of System 3’s machines and operating methods differed from those in Systems 1 and 2. The objectives of the study were to: 1. Determine whether or not commercial simulation software can be used to adequately model forest harvesting operations. 2. Gauge potential system balance, production and/or cost improvement/s achievable through application of simulation-based operation adjustments. 3. Define beneficial equipment operation and application practises for multi-stem systems. 4. Through construction and use of the commercial software package in producing forest harvesting operation models, evaluate the software’s usability in terms of its applicability to and ease of use in such models, as well as its ability to meet forestrybased user requirements.
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Wilson, Craig D. "Simulation of FET device technology for operation of high ambient temperatures." Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241555.
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Zheng, Pengjun. "A microscopic simulation model of merging operation at motorway on ramps." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289589.
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Billing, P. J. "Computer simulation of plant operation for use in process operator training." Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760584.
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Xie, Xiongfei. "Operation Optimization and Water Quality Simulation of Potable Water Distribution System." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5406.
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A potable water distribution system (WDS) consists of pipes, pumps, valves, storage tanks, control and supporting components. Traditionally, it has two basic functions. First, provides end users with potable water at sufficient pressures and good water quality. Second, provides sufficient pressure and flow for fire fighting. Currently, potable water is still the least expensive material for fire fighting. To accomplish these two goals, water utilities have to consider the integrity and security of the water network. As a result, this research selected three research topics that are closely related to the daily operation of water utilities and water quality simulation.
The first study is on optimal sampling design for chlorine decay model calibration. Three questions are investigated: (1) What is the minimum number of chlorine sample locations a water network needs? (2) How many combinations of sampling locations are available? (3) What is the optimal location combination? To answer the first two questions, the mathematical expressions of the chlorine concentrations between any two sampling locations are developed and sampling point relationship matrices are generated, then a mixed integer programming (MIP) algorithm is developed. Once obtained, the solutions to the first two questions are used to calculate the chlorine decay wall reaction coefficients and sensitivity matrix of chlorine concentration wall reaction coefficients; then, sampling location combinations achieved in the second question are sorted using a D-optimality algorithm. The model frame is demonstrated in a case study. The advantage of this method, compared to the traditional iterative sensitivity matrix method, is that a prior knowledge or estimation of wall reaction coefficients is not necessary.
The second study is on optimizing the operation scheduling of automatic flushing device (AFD) in water distribution system. Discharging stagnant water from the pipeline through AFD is a feasible method to maintain water quality. This study presents a simulation-based optimization method to minimize total AFD discharge volume during a 24-hour horizon. EPANET 2.0 is used as hydraulics and water quality simulator. This is formulated as a single objective optimization problem. The decision variables are the AFD operation patterns. The methodology has three phases. In the first phase, AFD discharge capacities are calculated, whether existing AFDs are able to maintain chlorine residuals in the water network is also evaluated. In the second phase, the decision variables are converted to AFD discharge rates. A reduced gradient algorithm is used to quickly explore and narrow down the solution space. At the end of this phase, decision variables are switched back to the AFD operation patterns. In the third phase, simulated annealing is used to search intensively to exploit the global minimum. The method is demonstrated on the water system located at the south end of Pinellas County, Florida where AFD optimal operation patterns are achieved.
The third study is on simulating contaminant intrusion in water distribution system. When contaminant matrix is introduced into water distribution system, it reacts with chlorine in bulk water rapidly and causes fast disinfectant depletion. Due to the difficulties in identifying contaminant types and chemical and biological properties, it is a challenging task to use EPANET-MSX to simulate chlorine decay under contaminant attack. EPANET 2.0 is used in the study to accomplish this goal. However, EPANET 2.0 cannot directly simulate chlorine depletion in the event of contamination attack because it assigns one time-independent bulk reaction coefficient to one specific pipe during the simulation. While under contaminant intrusion, chlorine decay bulk coefficient is not a constant. Instead, it is a temporal and spatial variable. This study presents an innovative approach for simulating contaminant intrusion in water distribution systems using EPANET multiple times. The methodology has six general steps. First, test bulk reaction coefficients of contaminant matrix in chemical lab. The uniqueness of this study is that the contaminant matrix is studied as a whole. The investigations of chemical, biological properties of individual aqueous constituents are not needed. Second, assume the contaminants as nonreactive, using EPANET 2.0 to identify where, when and at what concentrations of the inert contaminants will pass by in the water network. Third, determine the number of chlorine residual simulations based on the results in step two. Fourth, use EPANET to simulate the chlorine residual in the water network without the occurrence of contamination. Fifth, assign contaminated bulk coefficients to contaminated pipes; use EPANET to simulate the chlorine residual in the pipe network. Lastly, the chlorine concentrations of the impacted moments of impacted junctions are replaced with the results calculated in step five. This methodology is demonstrated in the south Pinellas County water distribution system.
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Huang, Chien-Chia. "Frameworks for Visualizing Real-Time Construction Operation Simulations." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243627216.
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龐維宗 and Wai-chung Pong. "Interstage stock control for series production lines with variable operation times." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1985. http://hub.hku.hk/bib/B31207054.
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Rivera, Ramirez Hector David. "Flood control reservoir operations for conditions of limited storage capacity." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1464.
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The main objective of this research is to devise a risk-based methodology for
developing emergency operation schedules (EOS). EOS are decision tools that provide
guidance to reservoir operators in charge of making real-time release decisions during
major flood events. A computer program named REOS was created to perform the
computations to develop risk-based EOS. The computational algorithm in REOS is
divided in three major components: (1) synthetic streamflow generation, (2) mass
balance computations, and (3) frequency analysis. The methodology computes the
required releases to limit storage to the capacity available based on the probabilistic
properties of future flows, conditional to current streamflow conditions. The final
product is a series of alternative risk-based EOS in which releases, specified as a
function of reservoir storage level, current and past inflows, and time of year, are
associated with a certain risk of failing to attain the emergency operations objectives.
The assumption is that once emergency operations are triggered by a flood event, the risk
associated with a particular EOS reflects the probability of exceeding a pre-established
critical storage level given that the same EOS is followed throughout the event. This
provides reservoir operators with a mechanism for evaluating the tradeoffs and potential
consequences of release decisions.
The methodology was applied and tested using the Addicks and Barker Reservoir
system in Houston, TX as a case study. Upstream flooding is also a major concern for
these reservoirs. Modifications to the current emergency policies that would allow
emergency releases based on the probability of upstream flooding are evaluated. Riskbased
EOS were tested through a series of flood control simulations. The simulations
were performed using the HEC-ResSim reservoir simulation model. Rainfall data
recorded from Tropical Storm Allison was transposed over the Addicks and Barker
watersheds to compute hypothetical hydrographs using HEC-HMS. Repeated runs of
the HEC-ResSim model were made using different flooding and residual storage
scenarios to compare regulation of the floods under alternative operating policies. An
alternative application of the risk-based EOS in which their associated risk was used to
help quantify the actual probability of upstream flooding in Addicks and Barker was also
presented.
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Gronfula, Mohammed Ghazi. "Intelligent optimisation system for airport operation : Hajj Terminal in Saudi Arabia." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/10445.
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Airport operation level of service (LOS) and performance management are among the major concerns by any airport authority. Two aspects considered in that kind of measurement: passengers prospective and operators prospective. This thesis tries to combine both in its produced optimisation system. This study was carried out in the Hajj terminal of the King Abdul-Aziz international airport and classified the processing time among the most important measures affecting the users’ observation of the level of service. Produced survey has helped to generate performance measure upon passengers prospective. On the other hand a simulation model of the process flow is utilised to formulate driven data model of the terminal process flow operations. The model built on Arena software and correlation study is made from the multiple “what if” scenarios of the model. Then a linear regression is used to generate a model for each variable. Levenberg–Marquardt (LM) algorithm is used after to carry out better regression model then Neuro-Fuzzy (NF) model found to be more efficient as it is picked and used to generate a best observed prediction. The system is optimised through the generated Neuro-Fuzzy (NF) logic model using both Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). A validation in addition to the testing made in the optimisation system. Analysis shows a great deal of improvement in predictions using fuzzy logic instead of linear regression for all dependent variables. PSO and GA optimisations are carried out and compared to the actual results gathered from the Arena simulation report.
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Haugen, Nils K. "A simulation analysis of a Suppression of Enemy Air Defense (SEAD) operation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA356027.
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Thesis (M.S. in Operations Research) Naval Postgraduate School, September 1998."September 1998." Thesis advisor(s): Donald P. Gaver, Patricia A. Jacobs. Includes bibliographical references (p. 59). Also available online.
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Cho, Hee Jin. "DYNAMIC SIMULATION AND OPTIMAL REAL-TIME OPERATION OF CHP SYSTEMS FOR BUILDINGS." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-03312009-144452/.
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Combined Cooling, Heating, and Power (CHP) systems have been widely recognized as a key alternative for electric and thermal energy generation because of their outstanding energy efficiency, reduced environmental emissions, and relative independence from centralized power grids. The systems provide simultaneous onsite or near-site electric and thermal energy generation in a single, integrated package. As CHP becomes increasingly popular worldwide and its total capacity increases rapidly, the research on the topics of CHP performance assessment, design, and operational strategy become increasingly important. Following this trend of research activities to improve energy efficiency, environmental emissions, and operational cost, this dissertation focuses on the following aspects: (a) performance evaluation of a CHP system using a transient simulation model; (b) development of a dynamic simulation model of a power generation unit that can be effectively used in transient simulations of CHP systems; (c) investigation of real-time operation of CHP systems based on optimization with respect to operational cost, primary energy consumption, and carbon dioxide emissions; and (d) development of optimal supervisory feed-forward control that can provide realistic real-time operation of CHP systems with electric and thermal energy storages using short-term weather forecasting. The results from a transient simulation of a CHP system show that technical and economical performance can be readily evaluated using the transient model and that the design, component selection, and control of a CHP system can be improved using this model. The results from the case studies using optimal real-time operation strategies demonstrate that CHP systems with an energy dispatch algorithm have the potential to yield savings in operational cost, primary energy consumption, and carbon dioxide emissions with respect to a conventional HVAC system. Finally, the results from the case study using a supervisory feed-forward control system illustrate that optimal realistic real-time operation of CHP systems with electric and thermal energy storages can be managed by this optimal control using weather forecasting information.
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Prins, William Santiago. "Computer simulation with sensitivity analysis of an advanced composite material manufacturing operation." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-02022010-020123/.
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Sullivan, Kay Ueda 1980. "PIC simulation of SPT Hall thrusters : high power operation and wall effects." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17839.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.Includes bibliographical references (p. 77-79).
The fully kinetic Hall Thruster simulation built by [1] and used by [2] is further refined and used to obtain results for the P5 SPT Hall thruster at 3kw and 5kw operation. Performance data agree well with experiments [3], although very low values of anomalous diffusivity must be used for convergence. Particle temperatures and plasma potentials in the chamber are similar to experimental results, although charged particles and peak ionization rates are found further upstream than is observed experimentally. Electron transport mechanisms and the magnetic field configuration are analyzed for their physical consistency and effect on particle placement. Electron mobility rates are found to be physical although the reason for high Hall parameter is still unclear. Strong magnetic mirror effects, that are not reported in experimental data, are found in the simulation. Meanwhile, two sputtering models are added to the simulation and tested. A yield model based on [4]'s theories and implemented with [5]'s functions is found to agree well with experimental yield data for 300eV to 1000eV sources, but produces small yields at thruster operating conditions.
by Kay Ueda Sullivan.
S.M.
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Vaughan, Haydn. "Accelerated Corrosion Test with Operation Simulation of All-Aluminum Microchannel Heat Exchangers." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849775/.
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The HVAC&R industry is looking to transition from copper-aluminum heat exchangers to all-aluminum microchannel technology. The want for the transition stemmed from seeing the performance improvement of all-aluminum microchannel radiators in the automotive industry. Applications differ between the two industries; therefore, applying this technology for HVAC&R use must be validated. Research towards operating modes of an all-aluminum heat exchanger in a defined corrosive environment will provide the industry with a better understanding of heat exchanger design and heat exchanger material selection. The worth in this is preventing overdesign and producing more efficient heat exchangers. Furthermore, ASHRAE members and the corrosion community will find value in a defined corrosion system and corrosion test procedure. The information gained through past research has progressed assessment of material performance; however, the methods improperly simulate and expedite natural weathering. The most common method being used is the ASTM (American Society of Testing Materials) Sea Water Acetic Acid Test. The research discussed in this paper was focused on improving a standard corrosion system by implementing system modifications to simulate heat exchanger operation while performing a modified wet-dry cyclic test (e.g. ASTM G85 Annex 5). The goal is to produce results that are more representative of natural corrosion behavior and its forms. Current results were gathered from five of ten samples that underwent initial testing. Finally, possible improvements towards the chamber system and the test method, including the salt solution, are discussed.
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Kasimir, Viktor. "Frequency Simulation at Island Grid Operation of a SGT-800 Gas Turbine." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80797.
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A frequency simulation for island grid operation of a SGT-800 gas turbine has been developed using the swing equation derived for synchronous machines. With the ever expanding and changing power grid, the requirements for plants to comply with grid code is getting more strict. Accurate simulations is needed to ensure compliance with the grid codes when implementing a gas turbine into a grid. SIEMENS wants to stay on top of this as the grid code develops to ensure that their products are capable of providing what is required of them. A combination of the SIMIT and PCS7 software has been used to simulate a SGT-800 gas turbine with control system where SIMIT simulated the turbine and the control system controlled the process in PCS7. The frequency simulation comparison with real data from a SGT800 showed a satisfactory result and load changes and a full load rejection has been compared. Several benefits such as being able to answer customer questions regarding frequency effects on island grids and testing the frequency control system can be obtained. Furthermore the SIMIT solution would enable easier implementation on site since the control system and simulation model are held separate. This also implies that operator training can be easily implemented as a future project.
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Munshi, Mrinal. "Improvement of automotive wheel/spindle bearing assembly operation using FEM simulation technique." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413453789.
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Do, Nhu Y., and Xuan Thanh Le. "Improvements to the operation of wind power generators in Vietnam." Technische Universität Dresden, 2016. https://tud.qucosa.de/id/qucosa%3A32614.
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In Vietnam, the number of wind power generators has been increased yearly. Because of geophysical characters, the generation of these generators has different properties. It depends much on wind’s characteristics as well as the generation technology. Based on simulation implemented on Matlab, the paper analyzes the stability of national networks at PCC nods containing the connection of wind power station when there is a change of wind’s velocity or when there is an earth fault in grid. The analyzing results are used to suggest solutions to improve the stability and effectiveness of the whole system.Các nhà máy điện gió đang ngày càng gia tăng ở Việt Nam, do cấu tạo địa lý nên đặc điểm của nguồn điện này khá khác biệt so với các nguồn điện truyền thống khác. Nguồn điện gió phụ thuộc nhiều vào đặc điểm của gió và công nghệ sử dụng để phát điện gió. Nội dung chính của bài báo là khảo sát mức độ ổn định của lưới điện kết nối các nguồn điện gió tại nút kết nối chung khi có sự thay đổi về tốc độ gió hoặc khi trong mạng xảy ra sự cố chạm đất thoáng qua, từ đó đề xuất giải pháp nâng cao ổn định, tin cậy và nâng cao hiệu quả làm việc của hệ thống.
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Matthews, Patricia Aileen 1963. "Validation of a vehicle mobility computer model for heavy earthmoving equipment." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276946.
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The computer program WHEEL is a mathematical model which predicts off-road vehicle performance characteristics. The program was developed using empirical relationships resulting from mobility tests on conventional-sized trucks and tires. The model was subsequently validated by comparing the model's predicted values of vehicle performance parameters, such as net drawbar pull, slip, sinkage and torque, with field test results for conventional-sized vehicles. However, validity of the model for predicting the off-road mobility of vehicles with large diameter tires was not established. The purpose of this study was to provide this validation. Values of net drawbar pull and slip for a Case 2390 tractor with 70.2" diameter driven wheels predicted by computer program WHEEL compare favorably with traction data obtained from tractor performance tests conducted by the University of Arizona Department of Agricultural Engineering. Therefore, the model may be used confidently to analyze performance of vehicles with large diameter wheels.
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Seriš, Richard. "Simulace řízení provozu teplovodu s dlouhým potrubím." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229664.
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The objective of this diploma thesis is to design a model of long heat pipeline operation control using Matlab software. The model should simply correspond to real heat pipeline system Melnik – Praha. After this, simulate operation control of sets of pumps. The role is to simulate usual and critical modes of operations. After evaluation of results, optimize the conditions for operation control of this system.
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Hauser, Karina. "SIMULATION AND OPTIMIZATION OF A CROSSDOCKING OPERATION IN A JUST-IN-TIME ENVIRONMENT." UKnowledge, 2002. http://uknowledge.uky.edu/gradschool_diss/275.
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In an ideal Just-in-Time (JIT) production environment, parts should be delivered to the workstationsat the exact time they are needed and in the exact quantity required. In reality, formost components/subassemblies this is neither practical nor economical. In this study, thematerial flow of the crossdocking operation at the Toyota Motor Manufacturing plant inGeorgetown, KY (TMMK) is simulated and analyzed.At the Georgetown plant between 80 and 120 trucks are unloaded every day, with approximately1300 different parts being handled in the crossdocking area. The crossdocking areaconsists of 12 lanes, each lane corresponding to one section of the assembly line. Whereassome pallets contain parts designated for only one lane, other parts are delivered in such smallquantities that they arrive as mixed pallets. These pallets have to be sorted/crossdocked intothe proper lanes before they can be delivered to the workstations at the assembly line. Thisprocedure is both time consuming and costly.In this study, the present layout of the crossdocking area at Toyota and a layout proposed byToyota are compared via simulation with three newly designed layouts. The simulation modelswill test the influence of two different volumes of incoming quantities, the actual volumeas it is now and one of 50% reduced volume. The models will also examine the effects ofcrossdocking on the performance of the system, simulating three different percentage levelsof pallets that have to be crossdocked.The objectives of the initial study are twofold. First, simulations of the current system,based on data provided by Toyota, will give insight into the dynamic behavior and the materialflow of the existing arrangement. These simulations will simultaneously serve to validateour modeling techniques. The second objective is to reduce the travel distances in the crossdockingarea; this will reduce the workload of the team members and decrease the lead timefrom unloading of the truck to delivery to the assembly line. In the second phase of theproject, the design will be further optimized. Starting with the best layouts from the simulationresults, the lanes will be rearranged using a genetic algorithm to allow the lanes withthe most crossdocking traffic to be closest together.The different crossdocking quantities and percentages of crossdocking pallets in the simulationsallow a generalization of the study and the development of guidelines for layouts ofother types of crossdocking operations. The simulation and optimization can be used as abasis for further studies of material flow in JIT and/or crossdocking environments.
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Kamaludin, Adzhar. "A simulation approach for modelling and investigation of inventory inaccuracy in warehouse operation." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6750.
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This thesis is focused on a simulation modelling approach to address the inventory inaccuracy problems in a warehouse operation. The main motivation which led to this research was a desire to investigate the inventory inaccuracy issues that have been highlighted by a logistics company. Previous and current research into inventory inaccuracy issues is largely related to the development of RFID technology as a possible solution to inventory problems. Since the inventory inaccuracy related to RFID technology is focused on the overall measurement of inventory management and retail business, there are differences between this existing research and the research presented in this thesis which is focused on issues of inventory inaccuracy in a warehouse operation. In this thesis, warehouse operation is studied as a detailed sequence of processes that are involved in the flow of items physically in parallel with related information being stored in the computer system. In these processes there are many places where errors can occur in counting or recording details of inventory, or in physically moving, storing or picking items incorrectly. These details of a warehouse operation are used to develop a conceptual model of inventory inaccuracy in warehouse operations. The study also found that typically a product needs to be considered differently at different stages of its progress through a warehouse (and therefore within different sections of the conceptual model). This is because initially batches of a product are likely to be delivered from a supplier, therefore if errors occur soon after the product is delivered to the warehouse, the error might involve the whole batch (for example the batch may be misplaced and put in an incorrect storage location), or the error might involve just part of the batch (for example poor transportation by forklift truck may damage the packaging carton and some of the items within the carton). When the product is stored ready for meeting customer orders, it needs to be considered as individual items (and errors can occur in counting of individual items or individual items may be misplaced or stolen). Finally, when a customer order is received, the product will be picked and grouped to meet the requirements of the order (for example, one order may require 10 of the product whilst another order may require 20 of the product). Errors might again occur to the whole group or to just part of the group. (Continued ...)
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Kumlin, Jesper. "True operation simulation for urban rail : Energy efficiency from access to Big data." Thesis, Mälardalens högskola, Industriell ekonomi och organisation, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-44264.
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Bridgeman, Lee. "Simulation of industrial granular flow and its effects on the sinter plant operation." Thesis, Swansea University, 2010. https://cronfa.swan.ac.uk/Record/cronfa42559.
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The supply and bulk handling of raw materials is of fundamental importance in many facets of the manufacturing community, the scope of which ranges from mining to pharmaceuticals and critical aspects of steel production. This thesis is based on the development of a 3D spherical ''Discrete Element Method" (DEM) modelling code to assist in the computer simulation of granular flow through a steelworks industrial environment. Presented in this work is a thorough evaluation and review of DEM techniques, highlighting the variety of discrete elements, contact special searches and contact interaction forces. Also addressed here is a validation of the current DEM Fortran code, using the effects of frictional forces on particulate flowing behaviour, in terms of "Angles of Repose". The introduction of these forces followed a "Linear Spring Dash-pot" (LSD) method and "Soft Sphere" approach where contact penetration is small in comparison with element diameter. Both surface and boundary deformations were neglected during contact interaction and boundary conditions were implemented using a "Solid Works" 3D design package. The results of the validation and frictional inputs in this modelling case were used as a calibration to set initial parameters of the discrete elements when simulating different material size distributions, and inter-particulate bonding scenarios due to the influence of moisture. To introduce attractive force due to moisture a "Toriodal Approximation'' was used in conjunction with the "Soft Sphere" method that showed novelty in contact interactions between elements of differing radii. The model was ultimately applied to practical material flow situations that exhibit system deterioration and inter-particulate degradation leading to atmospheric dust suspension. To express quantitive information kinetic energy transfer was recorded at boundary impact scenarios to isolate regions of severe momentum change and high intensity flow rates. The resulting energy trend examinations relating to extensive theoretical application of the current model correlated strongly with actual equipment damage and material flow patterns. The acquisition of data in this format delivers a 3D insight into the internal dynamics of material flow through a domain and could be essential in developmental optimisation.
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Parekh, Rutu. "Simulation and design methodology for hybrid SET-CMOS logic at room temperature operation." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6137.
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The purpose of this thesis is to research the possibility of realizing hardware support for hybrid single electron transistor (SET)-CMOS circuits by a systematic approach of design, analysis and simulation. The metallic SET transistors considered in this work are fabricated within the chip interconnect layers using CMOS back-end-of-line (BEOL)-compatible processing. The CMOS process integration can be divided into front-end-of-line (FEOL) and BEOL processes. The FEOL includes processes required to form isolated CMOS transistors whereas BEOL is the second portion of the IC fabrication where the devices get interconnected through the wiring using multiple layers of dielectrics and metals. Therefore, metallic SET circuits can be easily stacked above the CMOS platform presenting a low cost, low thermal budget, improving the overall yield at high-volume production of highly integrated systems. This considerably decreases the interconnect parasitics and increases the density of functions while maintaining the overall acceptable performance. Many problems such as low current drivability, delay and small voltage gain that hinder SET technology for its implementation in integrated circuits can be alleviated by intelligent circuit design. Although a complete replacement of CMOS by SETs is unlikely in the near future, an augmentation of CMOS with SETs is desirable if interfacing from and to CMOS works well. Interfacing from CMOS to SET circuitry is simple as the current and voltage levels are small and in accessible range. But interfacing CMOS from SET circuits is delicate due to SET logic's low current driving capability for CMOS and its interconnect. There is no concrete research on the interface issue wherein a SET-only circuitry drives a CMOS and its interconnects. For such hybridization to become possible, it is necessary to demonstrate the SET logic driving capability for CMOS with sufficient current drive and output voltage. The core SET logic can be designed to operate at low voltage, but at the interface the output of the SET logic must be in a voltage range that can be fed to a CMOS input for proper logic functionality. It is hence necessary to develop and adopt a systematic design methodology for such hybrid circuits at a specific technology node for room temperature operation. In this thesis we will look at a generalized design methodology that can be applied to (a) develop a fabrication model with parasitic effect of a hybrid SET-CMOS and SET-only circuits, (b) design and analyze the SET based fundamental building block in hybrid SET-CMOS or SET-only circuit and (c) simulate such a circuitry to assess its merits. More specifically, we will address the interfacing issue of such hybrid circuits in which we exploit the maximum capability of a SET logic in terms of driving capability, voltage response and power for a room temperature operation. The result of this research motivates the application of SET logic in 2 stages realizing some properties beyond those of CMOS devices. The first stage is the heterogeneous integration at chip level around a CMOS core. In such a circuitry, the SET introduces new functionalities such as reconfigurable logic, random number-based circuits, and multiband filtering circuits that can be combined with CMOS based general purpose processors or I/O signal restoration. The second stage of application is to use a new information processing technology focussed on a "new switch" exploiting a new state variable to provide functional scaling substantially beyond that attainable solely with ultimately scaled CMOS.
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Sui, Di. "Characterization of HVAC operation uncertainty in EnergyPlus AHU modules." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51911.
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This study addresses 5 uncertainties that exist in the operation of HVAC systems, which will presumably affect the actual energy consumption of the HVAC system in comparison to the consumption under idealized bahavior. We consequently add these parameters and their uncertainty range into the source code, eventually resulting in an EnergyPlus program in which the HVAC operation uncertainty is embedded as so-called model form uncertainty. The upgraded EnergyPlus is tested for each parameter uncertainty separately, and to show the impact of each uncertainty albeit for hypothetical uncertainty ranges of the parameters.
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Gabibulayev, Magomed. "Dynamic modeling and simulation of snow removal operation in an intelligent transportation system environment /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Sohel, Mohammed Imroz. "Thermodynamic Modelling and Simulation for High Efficiency Design and Operation of Geothermal Power Plants." Thesis, University of Canterbury. Mechanical Engineering, 2011. http://hdl.handle.net/10092/5292.
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This thesis analyses long term and short term environmental effects on geothermal power plant performance and discusses adaptive ways to improve performance. Mokai 1 geothermal power plant has been used as a case study for this investigation. Mokai 1 is a combined cycle plant where the binary cycles are air-cooled. The plant performance of an air-cooled binary cycle geothermal power plant is dependent on the environment (resource characteristics as well as weather conditions). For modelling such a power plant, two time scales are of interest: the yearly basis for aggregate plant performance for design and operations; and the daily basis for hourly plant performances for an accurate dispatch prediction.
Adaptive methodology for long term performance improvement has been introduced in this work which would save money and effort in the future by keeping the provisions to adapt to changes in resource characteristics based on geothermal reservoir modelling. The investigation was carried out using a steady state computer simulator of Mokai 1 geothermal power plant. The steady sate simulator was built specifically for this work. The deviation in performance of various components is less than 5% compared to the original plant design. The model is very generic and it can be used for other plants with simple adaptation or can be used for future plant design.
One of the main contributions of this work is an iterative method for modelling the environmental effect on short term performance on the air-cooled organic Rankine cycle. The ambient temperature is identified as the most influencing parameter on short term performance which influences the performance of the whole cycle in two ways. Firstly, by changing the equilibrium pressure inside the condenser, the turbine outlet pressure changes and hence, the turbine pressure ratio also changes. The turbine pressure ratio is a major parameter determining power generated by a turbine; therefore, the plant output is affected. Secondly, by changing the condenser outlet temperature with the ambient temperature, the pump inlet and outlet condition and consequently vaporizer equilibrium temperature and pressure are influenced. The developed method sought the equilibrium conditions of both condenser and vaporizer iteratively. In short, ORC cycle shifts on the T-s plane depending on the ambient temperature. This method iteratively seeks the shifted ORC on the T,s plane.
Two case studies have been carried out to demonstrate the method. The developed method shows robustness and converges exponentially. The model is effective for cycles that use saturated vapour as well as superheated vapour. The model essentially assumes steady state operation of the power cycle. The possible unit time where this model can be applied is bounded by the time required by a system to come into steady state. The saturated vapour cycle yielded average error 4.20% with maximum error 9.25% and the superheated vapour cycle yielded average error 2.12% with maximum error 5.60%. The main advantage of the developed method is that it requires a minimum number of inputs: condenser (p,T), vaporizer (p,T), condenser heat load, turbine efficiency (overall), pump work and the extremum conditions of all the components. These inputs should represent typical operating conditions of a plant. The model can predict the appropriate plant performance depending on the system heat input (geothermal fluid flow in this case) and the heat sink temperature. As the method is based on basic thermodynamics rather than empirical or semi-empirical approaches, this method is widely applicable. The main focus of this work is on the ORC but the developed method is applicable to any closed Rankine cycle. In addition, application of the developed iterative method to predict plant performance based on mean yearly weather data is also discussed in the thesis.
Water-augmented cooling system and optimization of plant operating point parameters have been proposed as adaptive measures to improve short term performance. Developed iterative method has been used for the short term performance analysis. The water-augmented cooling system is specifically suitable to mitigate the reduced power output during the summer. The simulated average gain in power during the summer (Jan, Feb, Nov and Dec) of an ORC of Mokai 1 geothermal power plant by incorporating a water-augmented cooling system was 2.3% and the average gain for the whole year was 1.6% based on the weather data of Taupo for the year 2005. A cost benefit analysis showed that water-augmented cooling system is more economical compared to other alternative renewable energies considered to meet summer peak demand. From the green house gas emissions perspective, water-augmented cooling is a better option than the gas fired peaking plants.
Adaptive approach for short term performance improvement by optimizing operating point parameters of an air-cooled binary cycle has huge potential with possible maximum improvement in power output by about 50%. The optimization takes in to account the effects of the geothermal resource characteristics and the weather conditions. The optimization is achieved by manipulating cycle mass flow rate and vaporizer equilibrium condition. Further study on the optimizing operating points to achieve improved short term performance has been recommended for future work.
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Pina, Fulano Jasson. "The value of hydrological information in multireservoir systems operation." Doctoral thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/28228.
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La gestion optimale d’un système hydroélectrique composé de plusieurs réservoirs est un problème multi-étapes complexe de prise de décision impliquant, entre autres, (i) un compromis entre les conséquences immédiates et futures d’une décision, (ii) des risques et des incertitudes importantes, et (iii) de multiple objectifs et contraintes opérationnelles. Elle est souvent formulée comme un problème d’optimisation, mais il n’existe pas, à ce jour, de technique de référence même si la programmation dynamique (DP) a été souvent utilisée. La formulation stochastique de DP (SDP) permet la prise en compte explicite de l’incertitude entourant les apports hydrologiques futurs. Différentes approches ont été développées pour incorporer des informations hydrologiques et climatiques autres que les apports. Ces études ont révélé un potentiel d’amélioration des politiques de gestion proposées par les formulations SDP. Cependant, ces formulations sont applicables aux systèmes de petites tailles en raison de la célèbre « malédiction de la dimensionnalité ». La programmation dynamique stochastique duale (SDDP) est une extension de SDP développée dans les années 90. Elle est l’une des rares solutions algorithmiques utilisées pour déterminer les politiques de gestion des systèmes hydroélectriques de grande taille. Dans SDDP, l’incertitude hydrologique est capturée à l’aide d’un modèle autorégressif avec corrélation spatiale des résidus. Ce modèle analytique permet d’obtenir certains des paramètres nécessaires à l’implémentation de la technique d’optimisation. En pratique, les apports hydrologiques peuvent être influencés par d’autres variables observables, telles que l’équivalent de neige en eau et / ou la température de la surface des océans. La prise en compte de ces variables, appelées variables exogènes, permet de mieux décrire les processus hydrologiques et donc d’améliorer les politiques de gestion des réservoirs. L’objectif principal de ce doctorat est d’évaluer la valeur économique des politiques de gestion proposées par SDDP et ce pour diverses informations hydro-climatiques. En partant d’un modèle SDDP dans lequel la modélisation hydrologique est limitée aux processus Makoviens, la première activité de recherche a consisté à augmenter l’ordre du modèle autorégressif et à adapter la formulation SDDP. La seconde activité fut dédiée à l’incorporation de différentes variables hydrologiques exogènes dans l’algorithme SDDP. Le système hydroélectrique de Rio Tinto (RT) situé dans le bassin du fleuve Saguenay-Lac-Saint-Jean fut utilisé comme cas d’étude. Étant donné que ce système n’est pas capable de produire la totalité de l’énergie demandée par les fonderies pour assurer pleinement la production d’aluminium, le modèle SDDP a été modifié de manière à considérer les décisions de gestion des contrats avec Hydro Québec. Le résultat final est un système d’aide à la décision pour la gestion d’un large portefeuille d’actifs physiques et financiers en utilisant diverses informations hydro-climatiques. Les résultats globaux révèlent les gains de production d’énergie auxquels les opérateurs peuvent s’attendre lorsque d’autres variables hydrologiques sont incluses dans le vecteur des variables d’état de SDDP.The optimal operation of a multireservoir hydroelectric system is a complex, multistage, stochastic decision-making problem involving, among others, (i) a trade-off between immediate and future consequences of a decision, (ii) considerable risks and uncertainties, and (iii) multiple objectives and operational constraints. The reservoir operation problem is often formulated as an optimization problem but not a single optimization approach/algorithm exists. Dynamic programming (DP) has been the most popular optimization technique applied to solve the optimization problem. The stochastic formulation of DP (SDP) can be performed by explicitly considering streamflow uncertainty in the DP recursive equation. Different approaches to incorporate more hydrologic and climatic information have been developed and have revealed the potential to enhance SDP- derived policies. However, all these techniques are limited to small-scale systems due to the so-called curse of dimensionality. Stochastic Dual Dynamic Programming (SDDP), an extension of the traditional SDP developed in the 90ies, is one of the few algorithmic solutions used to determine the operating policies of large-scale hydropower systems. In SDDP the hydrologic uncertainty is captured through a multi-site periodic autoregressive model. This analytical linear model is required to derive some of the parameters needed to implement the optimization technique. In practice, reservoir inflows can be affected by other observable variables, such snow water equivalent and/or sea surface temperature. These variables, called exogenous variables, can better describe the hydrologic processes, and therefore enhance reservoir operating policies. The main objective of this PhD is to assess the economic value of SDDP-derived operating policies in large-scale water systems using various hydro-climatic information. The first task focuses on the incorporation of the multi-lag autocorrelation of the hydrologic variables in the SDDP algorithm. Afterwards, the second task is devoted to the incorporation of different exogenous hydrologic variables. The hydroelectric system of Rio Tinto (RT) located in the Saguenay-Lac-Saint-Jean River Basin is used as case study. Since, RT’s hydropower system is not able to produce the entire amount of energy demanded at the smelters to fully assure the aluminum production, a portfolio of energy contacts with Hydro-Québec is available. Eventually, we end up with a decision support system for the management of a large portfolio of physical and financial assets using various hydro-climatic information. The overall results reveal the extent of the gains in energy production that the operators can expect as more hydrologic variables are included in the state-space vector.
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Xiong, Yunjie. "A BIM-based Interoperability Platform in Support of Building Operation and Energy Management." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97364.
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Building energy efficiency is progressively becoming a crucial topic in the architecture, engineering, and construction (AEC) sector. Energy management tools have been developed to promise appropriate energy savings. Building energy simulation (BES) is a tool mainly used to analyze and compare the energy consumption of various design/operation scenarios, while building automation systems (BAS) works as another energy management tool to monitor, measure and collect operational data, all in an effort to optimize energy consumption.
By integrating the energy simulated data and actual operational data, the accuracy of a building energy model can be increased while the calibrated energy model can be applied as a benchmark for guiding the operational strategies. This research predicted that building information modeling (BIM) would link BES and BAS by acting as a visual model and a database throughout the lifecycle of a building. The intent of the research was to use BIM to document energy-related information and to allow its exchange between BES and BAS. Thus, the energy-related data exchange process would be simplified, and the productive efficiency of facility management processes would increase.
A systematic literature review has been conducted in investigating the most popular used data formats and data exchange methods for the integration of BIM/BES and BAS, the results showed the industry foundation classes (IFC) was the most common choice for BIM tools mainly and database is a key solution for managing huge actual operational datasets, which was a reference for the next step in research.
Then a BIM-based framework was proposed to supporting the data exchange process among BIM/BES/BAS. 4 modules including BIM Module, Operational Data Module, Energy Simulation Module and Analysis and Visualization Module with an interface were designed in the framework to document energy-related information and to allow its exchange between BES and BAS. A prototype of the framework was developed as a platform and a case study of an entire office suite was conducted using the platform to validate this framework. The results showed that the proposed framework enables automated or semi-automated multiple-model development and data analytics processes. In addition, the research explored how BIM can enhance the application of energy modeling during building operation processes as a means to improve overall energy performance and facility management productivity.Doctor of Philosophy
Building energy efficiency is progressively becoming a crucial topic in the architecture, engineering, and construction (AEC) sector, promising appropriate energy savings can be achieved over the life cycle of buildings through proper design, construction, and operation. Energy management tools have been developed towards this end. Building energy simulation (BES) is a tool mainly used to analyze and compare the energy consumption of various design/operation scenarios. These instances include the selection of both new and retrofit designs and for building codes, building commissioning, and real-time optimal control, among others. The main challenge surrounding BES is the discrepancy between quantitative results and actual performance data. Building automation systems (BAS), or a part of BAS which is often referred to as building energy management systems (BEMS), works as another energy management tool to monitor, measure and collect operational data, all in an effort to optimize energy consumption. The key disadvantage to the more general tool of BAS in energy management is that the data sets collected by BAS are typically too large to be analyzed effectively. One potential solution to the lack of effective energy management analysis may lie in the integration of BES and BAS. Actual operational data can be compared with simulation results in assessing the accuracy of an energy model while the energy model can be applied as a benchmark for evaluating the actual energy consumption and optimizing control strategies. The presented research predicted that building information modeling (BIM) would link BES and BAS by acting as a visual model and a database throughout the lifecycle of a building. The intent of the research was to use BIM to document energy-related information and to allow its exchange between BES and BAS. Thus, the energy-related data exchange process would be simplified, and the productive efficiency of facility management processes would increase. More specifically, this research posits the framework of integrating BIM, BES, and BAS to produce a seamless and real-time energy-related information exchange system. The proposed framework enables automated or semi-automated multiple-model development and data analytics processes. In addition, the research explored how BIM can enhance the application of energy modeling during building operation processes as a means to improve overall energy performance and facility management productivity.
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Hofferberth, Dieter. "Modellierung und Simulation von Tätigkeitsstrukturen in der Teilefertigung des Maschinenbaues." Doctoral thesis, Universitätsbibliothek Chemnitz, 2004. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200400334.
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In der Arbeit werden mit der Bedienungstheorie eine analytische und mit der Simulationstechnik eine experimentelle Methode zur Gestaltung von Mehrstellenarbeit in der Teilefertigung behandelt.
Der theoretische Kontext wird über die Arbeitspsychologie mit der Handlungsregulationstheorie und den Operativen Abbildsystemen als Erklärungsmodell sowie den verschiedenen Ebenen der psychischen Regulation von Arbeitstätigkeiten hergestellt. Ein Praxisbeispiel zur Planung und Bewertung eines Arbeitsbereiches einer Teilefertigung mit Mehrstellenarbeit hinterlegt das Theoriegerüst.
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Bianchi, Adam, and Gabriel Nylander. "Operation and Control of HVDC Grids." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229460.
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Meshed high-voltage direct current grids are becoming an increasingly important technology for integrating renewable energies into the power system. To control the grids in the best possible way, optimal converter and grid control strategies are needed. This project studies how a four-terminal high-voltage direct current grid is operated and controlled by implementing different grid and converter control strategies. The grid control strategies examined are centralized voltage control and distributed voltage control with and without deadband. Simulations are made in the software PSCAD. Different fault types on the grid are studied to investigate how the power flow and voltage level are affected. An optimal value for both the deadband width and droop constant has been identified. Moreover, the results indicate that centralized droop control is not a suitable grid control strategy, whereas distributed voltage control with and without deadband are. The fault study indicates no differences between distributed voltage control with and without deadband. The power flow and voltage levels are identical for all fault types.Högspända likströmsnät spelar en allt större roll med att integrera förnyelsebar energi i våra elnät. För att styra dessa nät på bästa möjliga sätt krävs optimala omvandlar- och nätkontrollstrategier. I detta projekt studeras hur ett fyrterminalt högspänt likströmsnät kan styras och drivas genom att implementera olika omvandlar- och nätkontrollstrategier. De nätkontrollstrategier som studerats är centraliserad spänningskontroll och distribuerad spänningskontroll med och utan ett spänningsintervall. Alla simuleringar har utförts i programmet PSCAD. Olika fel i nätet har även studerats för att undersöka hur effektflödet och spänningsnivån påverkas. Ett optimalt värde på både spänningsintervallet och droop konstanten har identifierats. Dessutom har resultat som indikerar att centraliserad spänningskontroll inte är en lämplig nätkontrollstrategi erhållits, medan distribuerad spänningskontroll med och utan spänningsintervall är det. Felsimuleringarna påvisar ingen skillnad mellan distribuerad spänningskontroll med och utan spänningsintervall. Effektflödet och spänningsnivån är identiska för alla fel.
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Chinbat, Undram, and Soemon Takakuwa. "USING OPERATION PROCESS SIMULATION FOR A SIX SIGMA PROJECT OF MINING AND IRON PRODUCTION FACTORY." IEEE, 2008. http://hdl.handle.net/2237/12109.
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LIN, SONG-CHING, and 林松青. "ANALYTIC-BASED SIMULATION AND OPTIMIZATION FOR OPERATION." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/66985353875366937748.
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博士國立中央大學
土木工程研究所
90
Generally, a water resources system consists of two major facilities :(1) reservoir; (2) barrage. The reservoir is to regulate the variability of surface water flow and make water available when it is needed, and the barrage is used to divert water through the stream. Study on the firm yield analysis and operating rule curves for such a system will provide a long-term guideline for reservoir system operation. Optimization of water resources planning and management was studied in the last four decades, however, the topic is still a formidable challenges to water resources planner. The major advancement in this thesis, compared with previous studies, is to provide analytic solutions for reservoir releases in firm yield analysis on regional multireservoir and barrage systems. Furthermore, a GA (genetic algorithms) search technique is proposed to find a set of rule curves by using different approaches in coding and decoding. According to several numerical experiments on case studies reveal that automated model for rule-based operation can overcome computationally intractableness due to curse of dimensionality for reservoir operation problems in real world. The study attaines the following findings and conclusions: 1. A complete simulation model for a reservoir system operation can quickly reveal various factors influencing operation efficiency of the system, and can reduce the difficulties previously encountered. Meanwhile, a pseudo tandem reservoir model was developed to enhance the convenience of model modifications and calibrations. The maximum deviation of the simplification is only 4.08%, therefore, the simlified model is valid for preliminary planning . 2. For a reservoir-river system with its water abstraction point at an intake downstream of the dam, streamflow controlled by the dam can be utilized to significantly increase the water yield of the system. If more than one reservoirs in upstream, joint operation will make more efficient due to the complement by each others. Regarding reservoirs in series, the inflow of a downstream reservoir is the released amount of the upstream reservoir plus the lateral flow between those two reservoirs, and varies with the operation strategies of the upstream reservoir. As those reservoirs have almost the same source of water, the time distribution of inflows of reservoirs is nearly the same. This is the major difference between tandem and parallel reservoir systems. The results of this study indicate that operation of a multireservoir system in series has an efficient way to release for downstream reservoir with first priority for water supply purpose; For reservoirs in parallel, a strategy called balanced level indices (BLI) is verified to be the best for operating the multireservoir system with a water-intake located in the downstream of the confluence of all the related rivers. 3. Joint operation of reservoirs and barrages can enhance operation efficiency for water-supply. To reduce its impacts on environment, ecology and culture, development of water resources should start from building small scale dam incorporated with barrage rather than building a large dam. Traditional yearly reservoir utilization ratio, i.e. the ratio of the yearly firm yield and reservoir effective volume(Y/TV), greater than 1.0 represents a hydrological feasibility for dam construction. But, in the case of joint operation of multireservoir and barrages, the ratio is usually larger than 2.0, and means a high development efficiency. 4. Although each reservoir storage level varies with different operation strategies in a multireservoir system, the total storage function rises due to system joint operation. In order to gain the highest benefits, the system operation needs to obey rule curves. Therefore, deriving a proper rule curves can not only reduce the shortage amount and duration for downstream demand but also enhance hydropower efficiency. 5. Related to the optimization of reservoir operating rules, this study presents a new procedure to find a set of rule curves by different approaches in coding , decoding and choosing objection function . Those objection functions such as (1/SI), (1/SI+hydropower) and ((1/SI+hydropower)+(100-percentage of maximum shortage ratio)), employed to the fitness function of GA, resulted in a set of satisfied rule curves. 6. Nowadays, there is a trend to remain minimum instream flow discharge and the required water riverbed percolation in the downstream of a dam. The minimum instream flow is released for aquatic species and downstream riverbed percolation for recharging groundwater aquifer. The results of present studies reveal that the amount of downstream riverbed percolation is affected by not only the total amount but also the temporal distribution of stream discharge. The paper confirms that appropriate policy for reservoir operation can enhance total amount of riverbed percolation. 7. Because computations of the water yield involves a lot of cumbersome and time-consuming, a visual simulation model developed by Microsoft Visual Basic is presented to reduce the numbers of trial and error and the analysis time for firm yield in multireservoir-river systems.
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Ko, Yi-Feng, and 柯義峰. "Applying Genetic Algorithm on Construction Operation Simulation." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/79858846248989286108.
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碩士朝陽科技大學
營建工程系碩士班
89
Computer simulation has been applied on construction operation for many decades. For finding out how to change operation processes or choosing which resource combination would improve system’s performance, simulation has to run all possible alternatives of resource combination. Therefore, simulation is not considered as an optimization technique. Since Holland proposed Genetic Algorithms (GAs) in 1975, GAs has been widely used for solving optimization problems in different research areas and gaining good performance. This research presents a general-purpose computer simulation system used in construction simulation that applies GAs as a pre-processor for filtering the resource combination that has good influence on system performance. Then, simulation can be treated as an optimization technique for selecting good resource combinations to improve the performance of construction operations. A CYCLONE-based computer simulation system COST (Construction Operation Simulation Tool) is adopted for integrating with GAs and the new system is named as GA-COST. Case run for verifying the effects of adopting GAs to enhance the optimization capability of computer simulation system shows positive conclusion.
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Pu-Hao, Huang, and 黃匍豪. "3D AR-based Simulation for Construction Operation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/47uj28.
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碩士國立臺灣科技大學
營建工程系
99
Currently, integrated applications for construction operation simulation and 3D visual technology are mainly used during the post-processing phase of simulation operations. In other words, 3D animations are used to illustrate the detailed perceptual intuition of simulated results. However, text files and modules in 2D flow diagrams are more commonly used to define the issue being simulated during the pre-processing phase of the simulation. This type of simulation fails to illustrate the detailed perceptual intuition of the issues being simulated, and its structure also makes it difficult to synchronize and integrate with the actual field status for evaluation. This study proposed a construction module for 3D visual construction operation simulations. The construction simulation modules being built are simulated 3D field settings which contain property parameters for each simulation component. These simulation components are integrated from the simulation data and are then integrated with Augmented Reality (AR) technology to allow the 3D module to be superimposed on photos or real-time images of the construction site. The integration of virtual and practical 3D field-setting simulations offers a detailed representation which matches the actual field setting. During the study, we analyzed and examined various simulation modules for construction programs and the types and ranges of parameters used for building the information system . The relationship between these 3D field-setting simulations were also analyzed and examined. After initial studies and planning, the classes and property parameters of each construction simulation module component were proposed, along with a standard operation procedure to build the simulation. Stroboscope software provided a text interface and we used it as the base system for engine development during construction simulation to represent the proposed module construction. 3D simulation modules were then built based on the proposed program, and the parameters of each module components were extracted during system conversion. These parameters were then entered as text files in the construction simulation program to perform analysis. After data analysis using the proposed system, the initial time for each machine and tooling component at each node were extracted from the output file. The 3D modules could then be directly illustrated as real time animation on the final field-setting simulation
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Kao, Chia-chun, and 高嘉俊. "A Simulation Study on Operation Room Scheduling." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/v3kmyt.
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碩士國立中山大學
應用數學系研究所
103
Controling the running cost of the operating rooms is one of the key points for the hospital management. The cost of operating rooms is high consumption items for the hospital. The effectiveness of operating room is associated with the operating scheduling. Because there are some restrictions for the operating scheduling, for example, the working schedules of doctors or restrictions on the use of the operating rooms. So operating scheduling usually depends on experienced staffs. However, if the schedule is not good enough, it may cause the overtime probability become too high or the utilization rate too low. This work uses data set from the gynecology department of a major teaching hospital in southern Taiwan. Mixture log-normal distributions are identified to be acceptable statistically in describing the operating times. We estimate the overtime probabilities and corresponding costs according to the combinations of different operating types. In the process of making up the schedules, measures are assigned according to the operating types as well as their status. Moreover, there may also be some restrictions with respect to misjudgment of the operating status by the doctors due to possible unexpected complications during the operations. Here, we provide a scheduling strategy, called the minimum scoring strategy, for minimizing the operating times based on the possible operations coming into the system and complying restrictions mentioned above, using the scoring measures assigned. From the simulation results, the proposed method can effectively reduce overtime probabilities and costs, as well as the idling times of the operating rooms.
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Meng-ChiehSue and 蘇盟傑. "Operation and Simulation of Quantum Communication Satellite." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/z468c7.
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Shi, Wenlong, and 石文龍. "The Intelligent Simulation in Anesthesia during Surgical Operation." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/80945311437668880347.
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碩士元智大學
機械工程研究所
89
Depth of anesthesia (i.e. unconsciousness) is much harder to define and not readily measurable. In practice, anesthesiologists have a number of clinical signs and on-line measurements which can be used selectively for the determination of the patient''s state. In order to simulate the whole operation during inhalational anesthesia, a hierarchical architecture for the monitoring and control DOA includes four blocks, which are monitoring DOA, drug controller, patient model, and vaporizer model. The first block focuses on monitoring DOA using fuzzy model. Recently, the electroencephalograph (EEG) signals (i.e. bispectral index) has been approved that they related to unconsciousness more closely than cardiovascular indicators. Hence, the first level estimates of DOA from online bispectral index and end-tidal anesthetic agents (Etaa) are defined as a primary DOA (PDOA). The second level is focused on measuring cardiovascular signals, such as systolic arterial pressure (SAP) and heart rate (HR) to obtain an estimate of a secondary DOA (SDOA). Hence, using the first level and second level, we fuse these two factors using fuzzy model to decide the DOA. Block 2 is a drug controller that controls the drug infusion to the patient according to a fuzzy logic controller. In the third block, a four-input and four-output artificial neural network has been designed for patient model. In the fourth block, a single input and output artificial neural network has been designed for vaporizer model. Finally, according to the 13 patients’ simulation of different set points of DOA, the average of drug consumptions of set point of DOA in 50 (i.e., AO), 30 (i.e., ASD), and 10 (i.e., AD) is 0.93±0.25 %, 0.69±0.24%, and 0.74±0.21 %, respectively. When compared with the routine clinical trials (i.e., 0.69 ±0.30 %), the set point of DOA in 30 is more close to clinical trials. We conclude that the routine clinical trials are always controlled DOA in 30 (i.e., anesthetic small deep) which is used less drugs than DOA in 50 (i.e., anaesthetic ok). After this successful simulation results, the anesthesiologists will have confidence to perform on-line automatic control of drugs in the operating theatre.
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Lin, Yi-Tein, and 林憶田. "Simulation of Earthmoving Operation with “Similar Resource” Consideration." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/60965328008470596984.
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碩士國立中央大學
土木工程研究所
87
Essentially every large civil or building project involves earthmoving operation. It is not atypical for a highway project, for instance, to have to move more than 1,000,000-m3 earth between locations. Several mega projects, such as the second freeway, the high-speed railroad, and the rapid transit railways are currently underway in Taiwan, which all involve the movement of a huge amount of earth. Substantial amount of project cost can be saved with a better planning of the operation. The earthmoving operation mainly involves the interaction of excavators and hauling trucks, while its efficiency also affected by factors such as the property of the earth, the moving distance, the road conditions, and so on. This research employs computer process simulation technique for the planning and analysis of earthmoving operation especially with the consideration of “similar resources.” Combinations of excavators and trucks with different capacities, performance efficiencies, and other attributes (similar resources) are tested out on a computer model (STROBOSCOPE) to study the significance of considering the “similar resources” in the planning and analysis of the operation. The objectives are to improve the productivity and the cost effectiveness of the earthmoving operation with optimized combinations (numbers and sizes) of excavators and hauling trucks employed in the operation.