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1
Kim, Kyong Ryun. "Second order accurate variance estimation in poststratified two-stage sampling." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5895.
Full textAbstract:
We proposed new variance estimators for the poststratified estimator of the population
total in two-stage sampling. The linearization or Taylor series variance estimator
and the jackknife linearization variance estimator are popular for the poststratified estimator. The jackknife linearization variance estimator utilizes the ratio, ^Rc, which
balances the weights for the poststrata while the linearization or Taylor series estimator
does not. The jackknife linearization variance estimator is equivalent to Rao's
(1985) adjusted variance estimator. Our proposed estimator makes use of the ratio,
^R c, in a different shape which is naturally derived from the process of expanding
to the second-order Taylor series linearization, while the standard linearization variance
estimator is only expanded to the first-order. We investigated the properties
and performance of the linearization variance estimator, the jackknife linearization
estimator, the proposed variance estimator and its modified version analytically and
through simulation study. The simulation study was carried out on both artificially
generated data and real data. The result showed that the second order accurate
variance estimator and its modified version could be very good candidates for the
variance estimation of poststratified estimator of population total.
2
Neff, Angela R. "Bayesian Two Stage Design Under Model Uncertainty." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30303.
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Traditional single stage design optimality procedures can be used to efficiently generate data for an assumed model y = f(x<sup>(m)</sup>,b) + ε. The model assumptions include the form of f, the set of regressors, x<sup>(m)</sup> , and the distribution of ε. The nature of the response, y, often provides information about the model form (f) and the error distribution. It is more difficult to know, apriori, the specific set of regressors which will best explain the relationship between the response and a set of design (control) variables x. Misspecification of x<sup>(m)</sup> will result in a design which is efficient, but for the wrong model.
A Bayesian two stage design approach makes it possible to efficiently design experiments when initial knowledge of x<sup>(m)</sup> is poor. This is accomplished by using a Bayesian optimality criterion in the first stage which is robust to model uncertainty. Bayesian analysis of first stage data reduces uncertainty associated with x<sup>(m)</sup>, enabling the remaining design points (second stage design) to be chosen with greater efficiency. The second stage design is then generated from an optimality procedure which incorporates the improved model knowledge. Using this approach, numerous two stage design procedures have been developed for the normal linear model. Extending this concept, a Bayesian design augmentation procedure has been developed for the purpose of efficiently obtaining data for variance modeling, when initial knowledge of the variance model is poor.<br>Ph. D.
3
Montes, Diez Raquel. "Optimal design of two-stage screens : a Bayesian approach." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342027.
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Baran, Gary Steven. "A two-stage experimental design procedure under dispersion effects." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/37246.
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Under heterogeneous variance, conventional optimal response surface experimental designs for estimating location models are no longer optimal. To address this deficiency. D and Q criteria appropriate under heterogeneous variance are developed. These criteria are then applied to demonstrate the improved efficiency of a proposed two-stage experimental design procedure. In the proposed procedure the first stage estimates the heterogeneous variance structure and the second stage augments the first stage to produce a total design that is Q or D-optimal for the estimated variance structure. The Q and 0 criteria not only direct the total design, but also suggest optimal designs for estimating dispersion effects in the first stage.
The efficiency of the proposed two-stage procedure is further enhanced if certain mild assumptions concerning variance structure are valid. These assumptions are formulated as a prior distribution and effectively stabilize the variance estimation in the first stage through a Bayes estimator.<br>Ph. D.
5
Ninov, Valentin. "Two-dimensional zero-phase FIR filter design with nonuniform frequency sampling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ43655.pdf.
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Yahya, Samir Ghazi. "Design and evaluation of two-stage travelling wave thermoacoustic cooler." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/15541/.
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The overall aim of this research is to investigate the underpinning science behind constructing a practical travelling-wave thermoacoustic refrigerator. At the outset, this was defined as a demonstrator that could be further developed into a means of thermal management of various enclosures – for example weather proof enclosures containing heat generating electronics, popular across the process industries. The practical requirements were set as 400 to 500 W of cooling power at 25 K temperature difference between the inside of the enclosure and the ambient. The initial research addressed issues of coupling the linear motors to such a refrigerator. This included analytical solutions of equations governing the electrodynamic behaviour of the motors, which lead to obtaining preferred acoustic conditions for their optimum performance. Meanwhile, a series of DeltaEC simulations was conducted to investigate possible configurations of the acoustic network that provide the required acoustic impedance matching. The project had the practical limitations of using two existing Q-drive linear motors. As a result, a refrigerator network has been developed which required a compliance and inertance matching a twin-alternator excitation and a two-stage looped-tube travelling-wave refrigerator. The second part of the research was concerned with engineering a practical demonstrator of the above refrigerator concept. DeltaEC simulations have been used to design a practical build and predict its performance characteristics. A prototype, based on helium pressurised at 40 bar and operating frequency of 60 Hz, has been subsequently built and commissioned. A number of experiments have been conducted to evaluate its performance “as built” followed by improvements including, in particular, the use of elastic membranes to supress Gedeon streaming. The prototype achieved a maximum temperature difference of 40ºC, minimum cold temperature of -7.5ºC, maximum COP of 2.05, highest COPR of 21.72% and total cooling power of 283W. Good overall agreement was found between modelling and experiments.
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Stampfli, John J. "Design of a two-stage multi-state experimental biogas reactor." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127871.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (pages 23-25).<br>Anaerobic digestion is a process that breaks down waste and other feed materials and produces biogas. A biogas reactor, or anaerobic digester, is designed to conduct anaerobic digestion in a closed environment and to collect the produced biogas. This is an important field of study because biogas is a renewable energy source. If it can be produced more efficiently, it may become a feasible alternative source of green energy. This thesis outlines the design of a lab-scale experimental reactor with a large range of functionality. The design permits many different environmental conditions, allowing anaerobic digestion to be thoroughly studied with one setup.<br>by John J. Stampfli.<br>S.B.<br>S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
8
Vatkar, Shirish Talia Jorge E. "Design of a two stage epicyclic gearbox in sintered metal gears." Diss., A link to full text of this thesis in SOAR, 2007. http://soar.wichita.edu/dspace/handle/10057/1183.
Full textAbstract:
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering..<br>"May 2007." Title from PDF title page (viewed on Dec. 29, 2007). Thesis adviser: George Talia. Includes bibliographic references (leaves 100-101).
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Hu, Bing, and 胡冰. "Feedback-based two stage switch architecture for high speed router design." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43278693.
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Zhao, Chao. "Design fully-integrated dual-band two-stage class-E CMOS PA." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804916/.
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In retrospect we can see that from the last century, wireless electronic technology has been in a rapid state of development. With the popularity of wireless communication, the power amplifier demand is rising. In general, magnitude, maximum noise figure, minimum noise figure, efficiency, and output power are important indicators of the amplifier. The IC industry is exploring how to reduce the additional cost and improve the high-frequency performance. Therefore, designing a strong adaptability and high cost performance of the PA has become a priority. As these technologies advance, the power amplifiers need to have better integration, lower cost, and lower power dissipation. Also, some special requirements are being asked in some areas, such as multi-mode and multi-band. In general, people have to use several power amplifiers parallel to frame a multifunction chip. Each of them working at different frequencies of interest has to have separate matching network, design, and area; also, the diversity amplifier prices will increase with the number of amplifiers, and its cost is also changed. In this thesis, because Class E power amplifier has lower power dissipation, 100% ideal efficiency, simple circuit structure, and strong applicability, the Class E is used as power amplifier in main stage. Moreover, in order to decrease input power and increase output power, the class A power amplifier is used as driver stage. It can use very small amount of power to provide a larger power. Moreover, we use a switched variable inductor and capacitor to constitute a dual band matching network which can let the PA work at more than one frequency. In fact, we design a Class A PA which is as a driver stage. Then, when we support 1 dBm input power, the driver stage can have 8 dBm output power. Also the output will be the input power for the main stage. When the Class E PA get 8dBm input power, it will export a 15dBm output power. Because the dual band matching network, the PA can work at 2.2 GHz and 2.6 GHz; also, the efficiency is 48% and 51%, and the both gains are 13 dB. In the future, in order to further improve the performance of the power amplifier and better multi-frequencies, more new designs with new structures should be investigated. Moreover, we need further research about design theory. In fact multi-frequencies power amplifier has a great potential in real application. It based on its special structure and design parameters.
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Zolna, Jesse S. "Two stage process model of learning from multimedia guidelines for design /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22668.
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Thesis (Ph. D.)--Psychology, Georgia Institute of Technology, 2008.<br>Committee Chair: Richard Catrambone; Committee Member: James Foley; Committee Member: Mark Guzdial; Committee Member: Paul Corballis; Committee Member: Wendy Rogers.
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Hu, Bing. "Feedback-based two stage switch architecture for high speed router design." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43278693.
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Nadsady, Kenneth Allan. "A two-stage method for system identification from time series." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176406389.
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Holliday, Timothy. "The design and analysis of engine mapping experiments : a two-stage approach." Thesis, University of Birmingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392569.
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Zhang, Jiayuan. "Two-Stage Operational Amplifier Design by Using Direct and Indirect Feedback Compensations." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103938.
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This paper states the stability requirements of the amplifier system, and then presents, and summarizes, the classic two stage CMOS Op-Amp design by employing several popular frequency compensation techniques including traditional Miller compensation, nulling resistor, voltage buffer, and current buffer. The advantages and disadvantages of all these compensation strategies are evaluated based on a standard performance which has a 70dB DC gain, a 60◦ phase margin, a 25MHz gain bandwidth, and a slew rate of 20 V/us requirements. All the designs and simulation results are based on a 180mm 1.8 V standard TSMC CMOS technology. Ultimately, the traditional Miller compensated Op-Amp (a single compensation capacitor amplifier) cannot meet all the requirements but all other techniques could with also a boost of performance in various aspects.<br>Master of Science<br>Two-stage CMOS operational amplifier has two input pins and one output pin. it is used to amplify the differential inputs signal and transfer it to the output side. Usually the input signals are too weak to be processed by the rest of the system units. So the Op-Amp can amplify the weak input signals which then can either be further modified for some specific applications by the rest units of the system or be the final output of this entire system. The role of the Op-Amp in analog and digital systems is as the role of transformers in the power system. So the output signal is required to have fast and stable responses to the inputs. This paper states some standard requirements of the Op-Amp in aspects of gain, stability, and operating frequency. Due to the classic design of two-stage Op-Amp has poor performance of stability and operating frequency, some compensation techniques are applied as the feedback networks to improve its performance. These techniques include traditional Miller compensation, nulling resistor, voltage buffer, and current buffer. The advantages and disadvantages of all these compensation strategies are evaluated based on a 180mm 1.8 V standard TSMC CMOS technology.
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Luo, Yamin. "System modeling and control design of a two-stage metering poppet-valve system." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4453.
Full textAbstract:
Thesis (Ph. D.)--University of Missouri-Columbia, 2006.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 18, 2008) Vita. Includes bibliographical references.
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Englund, Sofia. "Optimizing the design of two-stage ditches to improve nutrient and sediment retention." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415420.
Full textAbstract:
Negative effects on water quality are created by eutrophication of the world’s water resources. Mitigation measures have been implemented, but poor improvements in water quality have been observed. Two-stage ditches have the possibility to increase nutrient and sediment retention to reduce eutrophication in receiving water bodies. A two-stage ditch has floodplain terraces on each side of the ordinary main channel. The terraces are available for flooding during high water flows and enables decreases in flow velocities. However, more knowledge is needed about the two-stage ditch and its effect in Swedish landscapes. The aim of the project was to study the two-stage ditch design with focus on water retention. Optimization of the two-stage ditch design was made by modeling and simulating design parameters and vegetation in the software Hydrologic Engineering Center’s River Analysis System (HEC-RAS). An existing two-stage ditch in Sweden was used as base and comparison to the theoretical model. In addition, a climate change scenario was studied to evaluate the impact of increased storm events in a two-stage ditch. Results showed that increased retention time of water, nutrients, and sediments theoretically can be given by designing two-stage ditches with maximum terrace width and minimum terrace height, and with terraces angled away from the main channel. Vegetation should also be kept on both terraces and in the main channel of the two-stage ditch to increase retention time. The study also showed that the two-stage ditch design has the possibility to decrease peak water levels during storm events, which can be expected to increase in the future. The impact on transport of nutrients and sediments from more future extreme hydrological events needs further studies.<br>Negativa effekter i vattenkvalitet skapas av övergödning i världens vattenresurser. Åtgärder för att begränsa övergödningen har genomförts, men svaga förbättringar i vattenkvalitet har noterats. Tvåstegsdiken har möjligheten att öka retentionen av näringsämnen och sediment för att minska övergödning. Ett tvåstegsdike har terrasser på vardera sida om den vanliga mittfåran. Terrasserna är tillgängliga för översvämning vid höga vattenflöden, vilket möjliggör minskning av flödeshastigheter. Dock krävs mer kunskap för tvåstegsdiken och dess effekt i svenska landskap. Syftet med projektet var att studera designen av tvåstegsdiken med fokus på retention av vattenflöde. Optimering av tvåstegsdikens design genomfördes via modellering och simulering av designparametrar och vegetation i programvaran Hydrologic Engineering Center’s River Analysis System (HEC-RAS). Ett befintligt tvåstegsdike i Sverige användes som bas och jämförelse mot den teoretiska modellen. Ett scenario för klimatförändring studerades även för att utvärdera effekten i ett tvåstegsdike då fler stormevent sker. Resultaten visade att ökad retentionstid for vatten, näringsämnen, och sediment teoretiskt kan ges genom att designa tvåstegsdiken med maximal terrassbredd och minimal terrasshöjd, samt med terrasser vinklade bort från mittfåran. Vegetation bör även behållas på terrasser och i mittfåran av tvåstegsdiket för att öka retentionstiden. Studien visade även att tvåstegs- dikets design har möjligheten att minska toppflöden vid stormevent, vilka kan förväntas öka i framtiden. Påverkan på transport av näringsämnen och sediment från fler framtida extrema hydrologiska event kräver ytterligare studier.
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Morley, Graham. "The impact of ICT on teaching in design and technology at Key Stage Two." Thesis, University of Huddersfield, 2009. http://eprints.hud.ac.uk/id/eprint/6967/.
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This thesis investigates the impact of computers and interactive whiteboards on the teaching of Design and Technology in Key Stage 2. Their use within education is having an influence upon the curriculum. Various investigations into the impact of Information and Communication Technology have been undertaken but these have principally involved CAD and CAM work within Key Stages 3 and 4 Design and Technology. Very few studies have looked at Design and Technology in the earlier key stages or the impact upon teaching and pupils at Key Stages 1 and 2. The literature review focuses on four key areas surrounding the research investigation: Computer Aided Learning; Cognition regarding the relationship of problem solving and higher level thinking; Pedagogy and its relationship to the use of computers in the teaching of Design and Technology and a review of the Design and Technology guidelines and the related issues regarding their implementation. The research is based upon both qualitative and quantitative methodologies employing multiple sources of data collection. Quantitative data was collected through a survey of all primary schools in two Yorkshire Local Authorities. The qualitative data produced the basis for in-depth individual semi-structured interviews with a sample of Design and Technology Co-ordinators. The semi-structured interviews then formed the foundation for a focus group interview of Local Authority officers. Use has been made of an evidence trail which examines other sources of evidence such as conference papers, HMI, QCA, Ofsted and DfES reports. The main findings indicate that the core subjects of the National Curriculum are taking the vast majority of teaching time. A broad and balanced curriculum is therefore no longer being maintained in the schools studied. The evidence revealed that teachers were becoming familiar with the use of computers in the classroom. They understood the skills involved in using computers but were still uncertain as to the most suitable pedagogy. The majority of teachers who responded to the questionnaire and the semi-structured interviews, the Local Authority officers and some government departments regard the New Opportunities Funded (NOF) training as being a disappointment due to its over-ambitious aims and lack of pedagogical content. The introduction of interactive whiteboards (IWB) was initially viewed by teachers as another element of ICT to teach. However these have now been well received. Those teachers involved in the study are finding it difficult to find time to either keep pace with or develop their ICT skills. This is reflected in teachers’ limited use of computer programs. This is in direct conflict with the findings of Ofsted, which found that teachers were now using a broader range of programs. Please note that the term Local Education Authority no longer exists as a statutory body. Throughout this thesis the term Local Authority is used instead.
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Gcabva, Sibusiso Joshua. "Design of consistently near-optimal heat exchanger networks by a two-stage optimisation approach." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/21776.
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Bibliography: pages 225-231.<br>Research in the field of Heat Exchanger Network Synthesis has been active as far back as 1965. Although the problem statement has remained essentially unchanged since then, numerous techniques have been developed to solve the heat exchange problem. Despite significant progress achieved over the years, a number of design issues remain unresolved or vaguely understood. Consequently, consistent generation of near-optimal heat exchanger networks is not guaranteed. This project has therefore been undertaken to develop a flexible design technique that can be used to gain further insight into the nature of a heat exchanger network. The objective of this project was to develop a network design technique that could be used to consistently generate networks that are near optimal. The main feature of the network design technique developed is the application of the optimisation process at two levels. The first level is match optimisation, and the second level is network optimisation. The objective function to be minimised is the total annual cost. The total annual cost is the sum of the annual cost of energy and the annual cost of capital. The annual cost of energy is the sum of the annual costs of hot utilities and cold utilities. The annual cost of capital is the sum of the annual costs of process, hot utility, and cold utility exchangers.
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Zhang, Anqing. "Adaptive Two-Stage Optimal Design for Estimating Multiple EDps under the 4-Parameter Logistic Model." Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/27450.
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In dose-finding studies, c-optimal designs provide the most efficient design to study an interesting target dose. However, there is no guarantee that a c-optimal design that works best for estimating one specific target dose still performs well for estimating other target doses. Considering the demand in estimating multiple target dose levels, the robustness of the optimal design becomes important. In this study, the 4-parameter logistic model is adopted to describe dose-response curves. Under nonlinear models, optimal design truly depends on the pre-specified nominal parameter values. If the pre-specified values of the parameters are not close to the true values, optimal designs become far from optimum. In this research, I study an optimal design that works well for estimating multiple s and for unknown parameter values. To address this parameter uncertainty, a two-stage design technique is adopted using two different approaches. One approach is to utilize a design augmentation at the second stage, the other one is to apply a Bayesian paradigm to find the optimal design at the second stage. For the Bayesian approach, one challenging task is that it requires heavy computation in the numerical calculation when searching for the Bayesian optimal design. To overcome this problem, a clustering method can be applied. These two-stage design strategies are applied to construct a robust optimal design for estimating multiple s. Through a simulation study, the proposed two-stage optimal designs are compared with the traditional uniform design and the enhanced uniform design to see how well they perform in estimating multiple s when the parameter values are mis-specified.
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Huang, Kuo-Chung, and 黃國忠. "(SYS,SYS)Two-stage Sampling Design." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/45166014857135482631.
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碩士<br>淡江大學<br>管理科學研究所<br>85<br>The purpose of this paper first investigates the theory of
two-stage sampling method, then, by simulation process, we can
look for the optimal sample size. Next, comparing the
advantages and inferiorities between (SYS,SYS) and (SRS,SRS)
two-stage sampling method, we can obtain the difference of them.
The body of this article has five parts as following:1. Evaluate
both expected value and variance of the estimator of the
population mean.2. Find the unbaised estimator of the variance
of the estimator of the population mean.3. Compare the size
of variance between (SYS,SYS) and (SRS,SRS) two-stage
sampling method.4. Determine the optimal allocation of two-stage
sample size of (SYS,SYS) two-stage sampling method under cost
limition.5. By simulation analysis, we compare the differences
of variance between (SYS,SYS) and (SRS,SRS) two-stage
sampling method, and look for the sample size to minimize the
variance. In the process of simulation analysis, we can see
that the variance of optimal allocation possess relative
stable character. Hence, in practice, the values of cp/cs and
Ss/Sp can be not achieved much exactly while we compute the
sample size of the second-stage. In addition, using random
number to produce 600 standard normal distributions, the
variances of (SYS,SYS) two-stage sampling method which
possess a relative minimizion is significantly lower than the
variance of (SRS,SRS) two-stage sampling method when the
value of m equals to 3.
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Huang, Chih-Hao, and 黃致豪. "(SRS,SYS) Two-Stage Sampling Design." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/14196703710569379384.
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碩士<br>淡江大學<br>管理科學研究所<br>85<br>The objects of this study is to investigate the theory of
(SRS,SYS)two-stage sampling design, to find the optimal
allocation of sampling units, then to compare its with (SRS,SRS)
two-stage sampling design and to determine which one is better.
The summaries of this thesis are as follows: 1. To calculate
the expectation and variance of the estimated population
mean and total. 2. To find the unbiased estimator of variance
of the estimated population mean. 3. To compare variance
of (SRS,SYS)two-stage sampling with that of (SRS,SRS)two-
stage sampling by verification. 4. To consider the optimal
allocation of sampling units under the limitations of cost
and no cost by verification and simulation. 5. By the analysis
of simulation, to compare the differences between variance
of (SRS,SYS)two-stage sampling and that of (SRS,SRS) two-
stage sampling, and to find the number of sampling units which
makes the variance relatively minimum.
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Huang, Zhi-Hao, and 黃致豪. "(SRS,SYS) Two-Stage Sampling Design." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/92676054994352362846.
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Hsu, Wen-Feng, and 許文峰. "Two-stage Case-Cohort Sampling Design for Estimating Multistate Disease Natural History of Colorectal Cancer." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/45019700295543325501.
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碩士<br>國立臺灣大學<br>流行病學與預防醫學研究所<br>103<br>Background
Elucidating multi-state disease natural history is of paramount importance for the identification of subjects at greater risk for disease progression, the determination of appropriate inter-screening intervals, and the evaluation of efficacy of interventions such as population-based screening program. While the application of stochastic models to estimate the force of multi-state disease progression using data on population-based screening program is well developed, the collection of such big data is quite costly. Moreover, it is often not feasible to accrue costly biomarkers such as genetic determinants based on the whole target population to quantify their roles played in the identification of subject at increased risk for disease progression. The application of case-cohort design is an alternative solution to address this issue with efficiency.
Objectives
The thesis aimed to develop a generalized non-linear regression model for fitting the data obtained from the three-stage design in comparison with the conventional multi-state stochastic model taking the measurement error such as sensitivity into account using data on the population-based fecal immunochemical test (FIT) for colorectal cancer (CRC) screening in Taiwan for the disease natural history for CRC and the sensitivity of FIT.
Methods
In the Taiwanese Nationwide Colorectal Cancer Screening Program, residents aged 50 to 69 years w consisting of 1160884 subjects with repeat screen rate of 28.3% were invited to receive a biennial FIT, between January 1, 2004 and December 31, 2009. A total of 2494 and 195 CRCs were detected during the prevalent screen and the subsequent screen, and 694 interval cancers were ascertained. A continuous-time, progressive 3-state Markov model was constructed for estimating the natural history of CRC. We developed a generalized non-linear regression model based on the three-state progression model for the derivation of the force driving the initiation and the progression of disease. A method incorporating both the nature of multistate disease progression and a sampling scheme based on a case-cohort design to utilize the data with efficiency was developed. The performance of the proposed method compared that of full data using a range of sampling proportions for the states of disease progression was then explored.
Results
Applying the generalized non-linear regression model to the full data, the estimated annual rate of CRC preclinical detectable phase (PCDP) incidence was 75 per 105 (95% CI: 58-92 per 10¬5) and that for PCDP progress was 0.31 (95% CI: 0.23-0.40) yielding a mean sojourn time (MST) for 3.23 years (95% CI: 2.5-4.35 years). The MST was around 3.2-4.3 years and the test sensitivity was 78-82% after fitting the data. The model considering measurement error and the effect covariates (sex and age) on PCDP incidence rate give the estimated hazard ratio for male and the elders (older than 60 years) of 1.65 (95% CI: 1.31-2.08) and 2.05 (95% CI: 1.61-2.64) and the sensitivity was estimated at 80% (95% CI: 74-84%).
Applying the proposed algorithm for two-stage sampling scheme to the data derived by a series of sampling ratio using the covariate of sex and age demonstrated the influence of the reduction in sample size in terms of screen detected cancers and interval cancers.
Conclusion
A novel algorithm with a two-stage sampling design was developed to efficiently estimate the multistate outcome of the disease natural history and assess the effect of covariates on stage-specific transition rates. This new algorithm has been well demonstrated by using Taiwanese nationwide colorectal cancer screening program and can be easily extended to assess the causal effect of certain costly biomarkers on stage-specific transition on the basis of such a large population-based screened cohort.
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王迺聖. "Multivariate analysis in the two-stage sampling." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/33695791837779633776.
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Chen, Tzu-Wen, and 陳姿文. "Robustness Study of One-Stage and Two-Stage Sampling Procedures." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/93573136775706449967.
Full textAbstract:
碩士<br>淡江大學<br>數學學系<br>88<br>When the variances are unkown and unequal, the level of the usual F-test in analysis of variance (ANOVA) is sensitive.Bishop and Dudewicz (1978) developed a two-stage sampling procedure, and Chen and Chen (1998) derived a one-stage sampling procedure for testing the equality of normal means in ANOVA under heteroscedasticity. In this paper we show that the two-stage sampling procedure and the one-stage sampling procedure are robust when observations are drawn from normal distribution with equal or unequal variances;but they are not robust when observations are generated from chi-square or gamma distributions. We also present the new power tables for implementing the two-stage analysis of variance procedure (Bishop and Dudewicz (1978)). Finally, we compare the z values of the two-stage analysis of variance procedure and the two-stage range test procedure (Chen, Wu and Chang (1998)).
第二章 一 階 段 抽 樣 程 序 與 二 階 段 抽 樣 程 序 .................................................... 4
第三章 穩 健 性 研 究 ......................................................................................................... 9
第四章 二 階 段 變 異 數 分 析 法 檢 定 力 .................................................................... 24
第五章 二 階 段 變 異 數 分 析 法 和 二 階 段 全 距 檢 定 法 的 比 較 .....................31
參 考 文 獻 ..............................................................................................................36
附 錄 ......................................................................................................................... 38
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Hall, Kathryn B. "Economically optimal control charts for two stage sampling." Thesis, 1990. http://hdl.handle.net/1957/38195.
Full textAbstract:
Control charts are designed to monitor population parameters. Selection of a
control chart sampling plan involves determination of the frequency of samples, size
of each sample, and critical values to determine when the system is sending an out-of-control signal. Since the main use of control charts is in industry, a widely
accepted measure of a good sampling plan is one that minimizes the total cost of
operating the system per unit time.
Methods for selection of control chart sampling plans for economically optimal
X charts are well established. These plans focus on single stage sampling at each
sampling period. However, some populations naturally call for two stage sampling.
Here, the cost of operating a system per unit time is redefined in terms of two stage
sampling plans, and computer search techniques are developed to determine the control
chart parameters. First the sample sizes and critical values are fixed, and
Newton's method is used to determine the optimal time between samples. Then, a
Hooke - Jeeves search is used to simultaneously determine the optimal critical value,
sample sizes and time between samples. Adjustment to the latter is required whenever
any of the other three parameters change. Alternative methods are also discussed.
Information from a single sample is usually used to control shifts in both the
process mean and variance. With two stage sampling, this means two additional control
charts are used, one for each variance component. The computer algorithm
developed for selection of parameters for X charts is adapted by expanding the Hooke
Jeeves search region to a six dimensional space, now over three critical values, sample
sizes for both stages of sampling, and the time between samples.
These methods are applied to a real data set that requires two stage sampling. A
representative analysis of the sensitivity of the optimal sampling scheme to the input
parameters completes the paper.<br>Graduation date: 1990
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Yang, Ching-Fen, and 楊靜芬. "A Simulative Study on Estimations in Two-Stage Random Sampling." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/30522045650334190212.
Full textAbstract:
碩士<br>淡江大學<br>管理科學研究所碩士班<br>95<br>Sampling survey, through which all the information needed is obtained by means of limited personnel and expenditure, has become a widely-applied science recently. Generally, people overemphasize the designing of sampling methods, instead of the choosing of the estimators which, as a matter of fact, decreases sampling errors and is therefore supposed to be as important as the designing of sampling methods.
The object of this study is first to investigate the theory of two-stage random sampling design. Since it is very difficult to prove theoretically, we hope to choose suitable estimators, to diminish sampling errors, and to elevate accuracy in itself, while we try to compare, in a simulative way, the applicability of the estimators under certain conditions of population characteristics.
The summaries of this thesis are as follows：
1. To confer the estimator of the population mean.
2. To confer the estimator of the variance of the estimator of the population mean.
3. To simulate and compare the estimator of the variance between equal allocation, proportional allocation and Neyman allocation.
4. By theory and simulative analysis, to compare the difference of variance in (SRS,STS) two-stage random sampling.
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Hsu, Yu-Pin, and 許育賓. "Initial Sample Size Selection for the Two-Stage Sampling Procedure." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/14029638421057712690.
Full textAbstract:
碩士<br>淡江大學<br>數學學系碩士班<br>100<br>When observations are taken from populations that are normally distributed with unknown and possibly unequal variances, Bishop and Dudewicz (1978) proposed a two-stage sampling procedure for the analysis of variance problem under heteroscedasticity. The procedure is a design-oriented process which requires an initial sample at the first stage and additional observations at the second stage. In this article we discuss the relationship between the initial sample size n_0 and the final total sample size. Two indicators T and R are provided to help selecting the initial sample size.
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Tsai, Yung-Szu, and 蔡泳思. "On the Sample Sizes of One-Stage and Two-Stage Sampling Procedures under Heteroscedasticity." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/65627476668609050797.
Full textAbstract:
碩士<br>淡江大學<br>數學學系碩士班<br>99<br>One of the assumptions of test procedures in the conventional analysis of variance is the equality of error variances. When the variances are unknown and unequal, Bishop and Dudewicz (1978) developed an exact analysis of variance for the means of k independent normal populations by using a two-stage sampling procedure. Chen and Chen (1998) used a one-stage sampling procedure to test hypotheses of equality of means in ANOVA model. In this study, we will first thoroughly explore the optimal choice of the initial sample size, n_0, for both the one-stage and two-stage sampling procedures by simulation study. We also investigate the effect on inference about the means of the one-stage and two-stage procedures when the assumption of normality is violated.
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Chang, Jia-Bin, and 張家賓. "Exact Likelihood Inference for the ExponentialDistribution base on two–stage sampling." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/41451284054409801661.
Full textAbstract:
碩士<br>淡江大學<br>數學學系碩士班<br>96<br>In a life testing experiment, Type-I, Type-II, and Hybrid censored samples generally lead into some disadvantages, one is that it is inefficient to analyze because of the few number of failures, the other is that the cost becomes higher for a long observing time. In this paper, under the end time of sampling period censored, we propose two-stage sampling and set a criteria to determine whether to proceed to the second stage or not. Using this method, we can not only get an acceptable number of failures but also decrease the observing time to save the cost of the experiment.
When the n units are put on test and the failure times are independent and identically distributed as exponential with parameter theta, we discuss the maximum likelihood estimator, the probability density function, the confidence interval of theta . We also present one sample to illustrate all the results finally.
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Chen, Tsung-Yueh, and 陳宗岳. "Developing a Two-Stage Sampling Plan Based on the Process Capability Index." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95241660897293826674.
Full textAbstract:
碩士<br>國立清華大學<br>工業工程與工程管理學系<br>104<br>In the field of quality control, acceptance sampling plan has been one of the widely used statistical quality tools which provides the producer and the customer a general rule for lot sentencing by satisfying their specified quality and risk requirements. In this
paper, we propose a new-type acceptance sampling plan based on the popular used capability index Cpk which is specialized in measuring the required process capability for the producer and the customer. Different from the existing acceptance sampling plans which were developed by using single sampling strategy which is a lot-sentencing procedure in which one sample of n units is selected at random from the lot, and the disposition of the lot is determined based on the information obtained in this sample, we develop the new-type sampling plan by using Two-Stage sampling strategy which requires less sampling and provides one more chance to the submitted lot compared with the traditional single sampling plan. Otherwise, we analysis and discuss the performance of the proposed variables plans compared with the existing sampling plans including single sampling plan and repetitive group sampling plan. The results indicate that variables two-stage sampling plan can be served as an ideal sampling method for quality assurance whether in economically or efficiently. Finally, we not only tabulate
the plan parameters for various required quality levels and allowable risks and provided an example for practical applications.
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Chang, Chung-Young, and 張成勇. "Sampling Survey System (Simple random . System . Two-Stage),an application of 'GUI'." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/50695504822012820719.
Full textAbstract:
碩士<br>淡江大學<br>數學學系<br>84<br>Improvements in computer technology have helped to develop
statistical applications with significant promotion and
extensiveness. It is my sincerely hope that statistical
application can be popularly used in modern society. We
unually employ professionals who specialize in sampling survey
to process information of collected samples and to analyze
survey results . This costs money and time. To process data by
computer is quicken and more exact. If we can develop a set of
sampling system to provide the method of collecting samples and
to provide the user with basic statistical information,the user
could handle the information of sample quickly.Among those
statistical packages, SAS is considered something that will
have the ability to develop applications. If SAS/AF software
uses Object-Oriented Programming(OOP) to develop a sampling
survey system,an application of 'GUI'.With GUI-based application
by pointing and clicking on their selections with a mouse,the
system is user-friendly. The main purpose of the paper lies
on the use of SAS/AF software which can be applied to develp a
sampling survey system. (1)User can use the procedure of SAS
system without writing programs to enter a sampling survey
system. (2)According to the information of collected samples
and self-made method,SAS/AF software can provide the information
about a population quickly. (3)Sampling survey system can be
popularly applied in all kinds of occupations.
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CHANG, YI-WEI, and 張益偉. "Two-Stage Optimal Design of CompositeLaminated Plates." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/8u643n.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>機械工程系<br>95<br>The main purpose of this thesis is to maximize the fundamental frequency of composite laminated plates with various boundary conditions. The fundamental natural frequency is evaluated by using the finite element method. Based on the physical consideration that the outer layer has more stiffening effect than the inner layer in the bending of plates, a two-stage optimal design for composite laminated plates is proposed. In the first stage, the fiber orientation angles of the outer layers are taken to be optimization design variables, and the inner layers are assumed to be isotropic materials. In the second stage, the fiber orientation angles of all N layers are taken to be design variables, and the genetic algorithms with fine-tunning mutation is applied to search for the optimal solutions in the N-dimensional space. In addition, the method is applied to minimize the amplitude of composite laminated plates to harmonic excitations. Several numerical examples are illustrated in the thesis. The performance of the proposed two-stage optimization technique on the convergence and the accuracy is tested by comparing the optimal solutions with those using simple genetic algorithms.
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Lai, Jun-An, and 賴俊安. "Two-Stage Driver Design for Piezoelectric Actuator." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/qmkd88.
Full textAbstract:
碩士<br>中原大學<br>機械工程研究所<br>92<br>A driver for piezoelectric actuator for high and low range of frequency application is investigated. The first stage of the driver is boost DC converter associated with the full-bridge circuitry in the second stage. In low operating frequency, switching control with sinusoidal pulse width modulation (SPWM) is used in full-bridge circuitry, which converts the high voltage DC signal provided in the first stage into AC low frequency signal to drive the piezoelectric actuator. In high operating frequency, switching control with programmable pulse width modulation (PWM) is used in full-bridge circuitry in association with the high-voltage and high-frequency signal generated by the resonance circuitry. Single-chip microprocessor is used to <a href="http://www.ntsearch.com/search.php?q=design&v=56">design</a> the programmable operating frequency with digital control method to accurately achieve the purpose.
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Low, Yi-Chang, and 劉益彰. "High-rise Building Two-stage Design Method." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mpzaht.
Full textAbstract:
碩士<br>國立中央大學<br>土木工程學系<br>107<br>The Taiwan code is based on the principle that “No collapse in strong earthquake, reparable in normal one, and no damage in weak one.” However, the building is constructed with elastic design and aseismic design. It does not analyze the nonlinear behavior of the structure under earthquake. In order to understand whether the building has sufficient capacity to resist earthquake force after the design is completed, Therefore, a two-stage design method for building structures is proposed. Including elastic design and nonlinear deformation check, nonlinear analysis includes nonlinear pushover analysis and nonlinear dynamic time history analysis.
This study will establish a 30-story reinforced concrete building with this process, with the current design, the details of the nonlinear analysis phase are defined in reference to the Taiwan specification and the US specification, including the method of checking the nonlinear pushover analysis and the operation and checking method of the nonlinear dynamic time history analysis.
The results show that the nonlinear pushover analysis differs from the results of the nonlinear dynamic time history analysis. Therefore, for high-rise buildings, nonlinear dynamic time history analysis must be performed to confirm the building's response to earthquakes. In addition, the method of nonlinear dynamic diachronic analysis will be proposed to complement the imperfections of Taiwan's specification. In the aspect of selecting the seismic record, it is recommended to obtain information from the station adjacent to the construction site to ensure that it has the characteristics of the construction site. And the seismic record should be composed of the north-south direction and the east-west direction as the maximum direction seismic record, there are two methods to modified the seismic record, the Scaling method and the Spectral Matching method. The scaling method proposes to use the spectral acceleration value in the range of 0.2T to 1.5T of the seismic response spectrum as the basis for scaling, the average of the maximum-direction spectra for
iii
exceeds 90% of the target spectrum in the range of 0.2T to 1.5T In the study, the analysis result is similar to the matching method with the adjustment factor of 1.1 times and the scaling method with 0.9 times as the adjustment factor. Therefore, it is recommended that the adjustment factor of matching method shall use 1.1
Finally, we will summarize all the analysis results and propose a complete two-stage design method for high-rise buildings.
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林雅愉. "Development of a two-stage Re-sampling Strategy for the Classification of Imbalanced Data." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7tq8n6.
Full textAbstract:
碩士<br>國立交通大學<br>工業工程與管理系所<br>106<br>To construct a classification model to classify the future observations is an important issue in many fields. For the real-world data, the number of observations in each class is usually not the same, that is, the number of data in a particular class may significantly greater or smaller than that of other classes. Such a data is called imbalanced data. When a classification model is established for the imbalanced data, the classifier tends to classify most of the data into the majority class, results in high prediction accuracy, low prediction accuracy of the minority class. However, the prediction accuracy of the minority class is concerned in many cases. Hence to enhance the prediction accuracy of the minority class is very important. Many studies used try-and-error or synthetic minority algorithm to under-sampling or over- sampling the observations of majority and minority class, however, these method are not effective. In the first stage, the Dual Response Surface Methodology (DRSM) is utilized to find an optimal resampling strategy for the majority class and the minority class. In the second stage, using the optimal resampling strategy to adjust the number of observations in the majority and minority classes. The synthetic minority algorithm, Majority Weighted Minority Oversampling Technique (MWMOTE) is employed increasing the observations of minority class and the one-side selection to reduce the number of observation of majority class. Therefore, the objective of this study is to develop a two-stage resampling strategy for classifying the imbalanced data. Using the adjusted data of the minority and the majority classes to construct an effective classification model. The accuracy rate of classifying the observation in the minority class can significantly be improved. At last, two datasets from the website are used to demonstrate the effectiveness of the proposed method.
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Qing-Guo, Zhu, and 朱慶國. "Design and Fabricate of Two-axial Ultrasonic Stage." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/6y787v.
Full textAbstract:
碩士<br>國立清華大學<br>工程與系統科學系<br>92<br>Design and fabricate thin-disc edge-driving ultrasonic actuators as foundation to position stage system in this research thesis. Servomechanisms with ball screws are used in most of transportation systems now. But this type of mechanism has a backlash problem in positioning system and the cost is high to demand driving elements with precise dimensions. We plan to adopt thin-disc edge-driving ultrasonic actuators developed by us as actuating elements to drive X-Y table directly for sake of promoting precision positioning, avoiding electromagnetic interference, laminating mechanism design and reducing the cost. Then long distance and micrometer precise position can be achieved within the novel mechanism via the design of robust controller.
The mechanical design of ultrasonic actuator as well as X-Y table will be verified at first in research approach. The performance of ultrasonic actuators will be measured and the driving parameters will be set well by experimentation. Then the static and dynamic features of the constructed X-Y table will be measured and analyzed. Design single-input fuzzy logic controller as orienting control. Finally, combine it in double axles orient the electromechanical system of the stage and test the whole organization and performance of orientation, such as orienting test, speed of stage, step displacement. It makes it resist the disturbance to adjust the system parameter in order to possess the abilities of precision, stability and fast positioning. By this experimental result, using the double axles orienting stage and single-input fuzzy logic control can make the precision of oriented reach 0.5μm. As well as the ultrasonic actuators have capability as step motor, and its minimum step displacement can reach several micro of grades.
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Tang, Chun Wen, and 湯鈞汶. "Design of A New Type Two-Stage Refrigerator." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/16797762256938315769.
Full textAbstract:
碩士<br>國立臺灣大學<br>機械工程學研究所<br>88<br>The main purpose of the research is to develop and implement a two-stage refrigerator with binary refrigerant mixtures,
including R134a and Helium. It requests low temperature and high cooling capacity for CPU cooling. We use electro-magnetic valves to adjust operating frequency and duty cycle of pulse tube inlet pressure to improve system performance and control cold-end temperature. The test method is searching the coolest temperature by varying operating condition, analyzing system response, and conducting system identification for controller design.
The experiment results show that the cold-end temperature reaches -70℃ at 0.5 Hz and 50% duty cycle, and 30W cooling capacity at -10℃. It demonstrates the refrigerator can be applied in CPU cooling.
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Dai, Fang-De, and 戴芳德. "Design and Implementation of Two-Stage LED Driver." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/25558648453822980222.
Full textAbstract:
碩士<br>國立高雄第一科技大學<br>電子工程研究所<br>99<br>This thesis proposes a two-stage LED driver system which possesses two sets output source, in order to keeping the brightness of LED load. The first-stage of the proposed system is power factor correction circuit which possesses whole voltage range and implemented by boost converter. It can apply to 85~265V, 50/60Hz, the output voltage is 400V, so it can use to all over the world. The boost converter is operated in boundary conduction mode to improve the power factor. The second-stage of the proposed system is forward converter which is used to reduce input voltage 400V to 30V. The converter designs the third winding to transfer the magnetizing inductance energy to second winding for maintaining the output voltage stability. Finally, a two-stage driver circuit is implemented to identify the functionality and feasibility of the proposed system.
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Wu, Rong-hui, and 吳榮輝. "DESIGN OF TWO-STAGE BOOST POWER FACTOR CORRECTION." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/84559969850444277906.
Full textAbstract:
碩士<br>大同大學<br>電機工程學系(所)<br>97<br>ABSTRACT
This thesis presents the problem with respect to the dual boost technique of the power factor correction ( PFC ) application. In the PFC a series problem will occur when the PFC is worked in single boost ( only one section_PFC bus is 400V ) even in low mains input, it will then generate a low mains voltage of switching loss on the PFC MOSFET to reduce the efficiency in low mains input . Therefore, In order to prevent this issue happened, we need to change the design concept from single boost to two-stage boost which can improve the efficiency when the input is in low mains voltage for EPA standard application.
We knew that if we want to improve the efficiency in low mains voltage that is also passed EPA standard requirement which have to change the design concept to increase low mains voltage efficiency that means as below :
Low mains input_90Vac~160Vac : PFC voltage is setting in 250Vdc
High mains input_170Vac~264Vac : PFC voltage is setting in 400Vdc
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XU, HUAN-ZHI, and 徐煥智. "The two stage form feature based design concept." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/74096976401369557268.
Full text
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Tseng, Chun-Hua, and 曾俊樺. "Design of Two-Stage Power Amplifier MMIC for." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/cwzhuy.
Full textAbstract:
碩士<br>國立交通大學<br>電機學院電信學程<br>106<br>This thesis is divided into three major parts. The first part introduces the current development of wireless communication and describes the motivation of the research. It also aims at the IEEE 802.11b/g WLAN receiver system, and details the specifications of the current IEEE 802.11b/g WLAN system.
The second part of the thesis discusses the basic theory required for designing RF power amplifiers and related circuit design techniques, and verifies the correlation with theory by designing a 2.4 GHz ISM (Industrial, Scientific and Medical band) Class A RF power amplifier MMIC. The third part details the design of a 2.4~2.5 GHz power amplifier operating at 1.8V DC, and realized by the InGaP/GaAs Power HBT process of AWSC. The design includes the matching design of the S-parameters and matching design for maximum power output, In the design of the circuit, the Advanced Design System (ADS) 2009 is used to perform circuit simulations and IC layout .
At last, this thesis uses the basic theory to successfully complete the two-stage power amplifier, the operating frequency is 2.4~2.5GHz, the P1dB is 12dBm, the output power of 11g is 8.19dBm, the current consumption is 45mA, and the layout way of the transistor is also effectively modified to reduce the wafer the overall area, the final sheet area of 340um * 280um, to achieve a small area of low-power research.
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Hung, Shih-bo, and 洪士博. "Design and Control of Reactive Distillation Systems: One-Stage and Two-Stage Esterification." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/73559733918816505397.
Full textAbstract:
博士<br>國立臺灣科技大學<br>化學工程系<br>95<br>The design and control of various reactive distillation systems were systematically studied for two categories of heterogeneous catalytic esterification over acidic ion-exchange resins. A series of one-stage esterification of acetic acid with five different alcohols, from methanol to amyl alcohol, was selected as model systems for the first category, while two-stage esterification of adipic acid with methanol was chosen as an illustrative example for the second category. In the process simulations, the kinetic models were taken from literature and the thermodynamic models have been verified with experimental phase equilibrium data before use. The total annual cost (TAC) was adopted as the objective function for process optimization.
Three types of flowsheets were developed for those five one-stage esterification systems. The process development was mainly based on the phase behavior of the related mixtures such as boiling point ranking, immiscibility, and residue curve map (RCM). For each system, the degree of process nonlinearity was evaluated with the fraction of “sign reversal” of tray temperatures and the index of Allgower’s nonlinearity. The multiple steady-state phenomena were also found in most of the studied processes. Both dual-temperature control and one-temperature-one- composition control were investigated for each type of flowsheet. It was found that simple decentralized control was effective for those highly nonlinear reactive distillation systems.
For accurately analyzing the operation of liquid-liquid separation unit in the processes of two-stage esterification of adipic acid with methanol, liquid-liquid equilibrium (LLE) data of two ternary systems containing water, methanol and esters were measured in the present study. These LLE data were correlated with the NRTL model to determine the optimal binary interaction parameters. Two types of reactive distillation flowsheets were developed for this two-stage esterification system. Similarly, the process nonlinearity was also evaluated. Three kinds of temperature control structures were tested in this work. Satisfactory control performances have been achieved regardless of the control structures, but using different control structures lead to substantial difference in energy demands.
It is concluded that analysis the system characteristics first and then selection of correct control stratagem are keys to success for development of an efficient reactive distillation process, regardless of complexity of the reaction systems. As demonstrated in this study, good operability and controllability have been achieved for the processes which consist of only one reactive distillation column or plantwide complex reactive distillation systems.
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Backlund, Peter Bond. "A classifier-guided sampling method for early-stage design of shipboard energy systems." 2012. http://hdl.handle.net/2152/19624.
Full textAbstract:
The United States Navy is committed to developing technology for an All-Electric Ship (AES) that promises to improve the affordability and capability of its next-generation warships. With the addition of power-intensive 21st century electrical systems, future thermal loads are projected to exceed current heat removal capacity. Furthermore, rising fuel costs necessitate a careful approach to total-ship energy
management. Accordingly, the aim of this research is to develop computer tools for early-stage design of shipboard energy distribution systems. A system-level model is developed that enables ship designers to assess the effects of thermal and electrical system configurations on fuel efficiency and survivability. System-level optimization and design exploration, based on these energy system models, is challenging because the models are sometimes computationally expensive and characterized by discrete design
variables and discontinuous responses. To address this challenge, a classifier-guided
sampling (CGS) method is developed that uses a Bayesian classifier to pursue solutions with desirable performance characteristics. The CGS method is tested on a set of
example problems and applied to the AES energy system model. Results show that the CGS method significantly improves the rate of convergence towards known global
optima, on average, when compared to genetic algorithms.<br>text
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Lin, Cheng-Hong, and 林政宏. "Design Consideration of a Two-Stage Multiple Testing Procedure." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/49315428203801738961.
Full textAbstract:
碩士<br>國立臺灣大學<br>流行病學研究所<br>93<br>Multiple testing problem occurs when the simultaneous inference of multiple statistical tests is of interest. Two major concerns when design with multiple testing are type I error and power. In other words, a large power under limited false positive rate is the focus. However, as the number of tests increases, the overall false positive rate increases. Traditional Bonferroni’s method is conservative and controls overall false positve rate well. Consequently, its overall power is usually small. In association studies using SNP’s as genetic markers, it is common that the statistical power becomes more important than the type I error. This thesis focuses on a two stage design for multiple hypothesis testing. I will present the exact calculation of power and false positive rate under given conditions. An efficient algorithm for computation will also be presented. Analysis of possible influential factors will be investigated through simulation studies. Recommendations for the two stage design will be suggested, including choice of the sample size and using 0.05 as the first stage significance level.
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CHANG, CHUN-CHI, and 張俊吉. "Design of a Two-Stage Linear Micro-Feeding System." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/02751775477967154874.
Full textAbstract:
碩士<br>國立清華大學<br>動力機械工程學系<br>92<br>This paper proposes a design methodology for a two-stage linear micro-feeding system that includes a coarse-feeding subsystem, a fine-feeding subsystem and positioning subsystem. The coarse stage is driven by an array of thermal actuators through a compliant amplification mechanism. This gives it the ability to generate a rapid and long range of motion. When the coarse-feeding subsystem is moved to the desired position, the system is clamped by the positioning subsystem that features two compliant bistable mechanisms. The coarse-feeding subsystem has a range of 60 μm with a resolution of 3 μm. After the coarse stage moves into the desirable position, the scratch drive actuator shifts the fine stage to the desired position over a small range of 4 μm, with a large force of 165 μN, and a high resolution of 30 nm at a bias of 70V with an additional sine wave of amplitude 20V. Additionally, the pseudo-rigid-body model and Castigliano’s theorem were employed to derive the strain energy and the relationship between the output and input displacements of the amplification mechanism. These theorems were tested and matched the experimental results. The results of the experiments performed support the pseudo-rigid-body model and the widely accepted Castigliano’s method. The proposed micro-feeding system was fabricated by the MUMPs, which was provided by MEMSCAP.
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Chiou, Yun-Ren, and 邱韻仁. "Optimal Regulator Design for a Two-Dimantional Piezopositioning stage." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/22shyf.
Full textAbstract:
碩士<br>國立東華大學<br>電機工程學系<br>96<br>This thesis focuses on the topics concerning about modeling and tracking control of a two-dimensional piezopositioning stage. In the system modeling, the frequency response Bode diagram of piezopositioning stage is captured by a dynamic signal analyzer (DSA). From the Bode diagram, a second-order and a third-order transfer function are established by the Curve Fitting toolbox of MATLAB computer software. On the basis of these transfer functions, the control approach for trajectory tracking of the piezopositioning stage is proposed.
Instead of using the trial-and-error method, the linear quadratic regulator (LQR) method is adopted in the proposed control approach to find the appropriate parameter values. To show the validity of the proposed control approach, the control algorithm was implemented on a computer and then experimental results from the computer-controlled piezopositioning were illustrated.
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Hou, Jian-hong, and 侯建宏. "Design and Investigation of Two-Axis Micro-Positioning Stage." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72646315027415679225.
Full textAbstract:
碩士<br>國立中正大學<br>機械工程所<br>97<br>The main purpose of this thesis is to design a two-axis micro-position stage for the vacuum Lamination equipment in the ODF (One Drop Filling) manufacturing process. For the stage, the robust controller is designed such-that the behavior of micro-nano positioning can be achieved. The concepts of the technology obtained from this positioning stage will be transferred into large processing equipment such that the objective of the precision positioning can be obtained.
Because of mechanism design, manufacturing error and assembling error, the stage can result in the x-y axis coupling. If two SISO controllers are designed without considering the coupling, large tracking errors might occur. In this thesis, control of the two-axis positioning stage is taken as a MIMO system. The QFT (Quantitative Feedback Theory) is applied to design the controller such that the MIMO system can be treated as a decoupled system and the specifications can be satisfied. The experimental results show that in the step test, the maximum errors of the x-axis and y-axis does not exceed 0.2μm during the admissible moving range. As compared to using two SISO controllers, the MIMO controller could achieve much better performances.
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Chang, Cheng An-Che, and 張簡安哲. "Design Fuzzy Controller by A Two-Stage Genetic Algorithm." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/18663414632317880811.
Full textAbstract:
碩士<br>淡江大學<br>電機工程學系<br>85<br>It is necessary to control a system under a stable and safe state. Besides sufficiently realizing the characteristics of the system, the design of a controller is also a key point. That will improve the quality of the controller and meet with user''s requirements. Many approaches have been presented to design controllers in literatures. But most of them are often complicated. In this paper, an effective and simple algorithm, called the two-stage genetic algorithm (TSGA), is presented. It is based on the genetic algorithm and fuzzy set theory. This proposed algorithm has the following characteristics:
(1) The model of the plant to be controlled is not required.
(2) It is simple and easy to implement.
(3) The operator''s experience can be adopted into fuzzy rules and membership function to improve the performance of the controller.
(4) It has the ability to handle the multi-objective control problem and meet the operator''s requirements.
(5) It allows the designer to find an acceptable non-inferior solution.
From simulation results, the performance of TSGA fuzzy controller can be further improved than that of traditional fuzzy controllers. Also, it is expected that the proposed approach can be applied to other applications with good performance.