Understanding multistage experiments

Abstract: Current advanced manufacturing processes are composed of multiple complex stages which prohibit experimenters from conveniently employing traditional statistical experimental designs due to restrictions on randomisation. In this paper, we demonstrate, and summarise how split plot design and its variants have been used for multistage experimentation, and present several multistage experiment scenarios with comments for practitioners and researchers

Listing Unique Fractional Factorial Designs

Fractional factorial designs are a popular choice in designing experiments for studying the effects of multiple factors simultaneously. The first step in planning an experiment is the selection of an appropriate fractional factorial design. An appro- priate design is one that has the statistical properties of interest of the experimenter and has a small number of runs. This requires that a catalog of candidate designs be available (or be possible to generate) for searching for the "good" design. In the attempt to generate the catalog of candidate designs, the problem of design isomor- phism must be addressed. Two designs are isomorphic to each other if one can be obtained from the other by some relabeling of factor labels, level labels of each factor and reordering of runs. Clearly, two isomorphic designs are statistically equivalent. Design catalogs should therefore contain only designs unique up to isomorphism. There are two computational challenges in generating such catalogs. Firstly, testing two designs for isomorphism is computationally hard due to the large number of possible relabelings, and, secondly, the number of designs increases very rapidly with the number of factors and run-size, making it impractical to compare all designs for isomorphism. In this dissertation we present a new approach for tackling both these challenging problems. We propose graph models for representing designs and use this relationship to develop efficient algorithms. We provide a new efficient iso- morphism check by modeling the fractional factorial design isomorphism problem as graph isomorphism problem. For generating the design catalogs efficiently we extend a result in graph isomorphism literature to improve the existing sequential design catalog generation algorithm. The potential of the proposed methods is reflected in the results. For 2-level regular fractional factorial designs, we could generate complete design catalogs of run sizes up to 4096 runs, while the largest designs generated in literature are 512 run designs. Moreover, compared to the next best algorithms, the computation times for our algorithm are 98% lesser in most cases. Further, the generic nature of the algorithms makes them widely applicable to a large class of designs. We give details of graph models and prove the results for two classes of designs, namely, 2-level regular fractional factorial designs and 2-level regular fractional factorial split-plot designs, and provide discussions for extensions, with graph models, for more general classes of designs

Glosarium Matematika

273 p.; 24 cm

ISBIS 2016: Meeting on Statistics in Business and Industry

This Book includes the abstracts of the talks presented at the 2016 International Symposium on Business and Industrial Statistics, held at Barcelona, June 8-10, 2016, hosted at the Universitat Politècnica de Catalunya - Barcelona TECH, by the Department of Statistics and Operations Research. The location of the meeting was at ETSEIB Building (Escola Tecnica Superior d'Enginyeria Industrial) at Avda Diagonal 647. The meeting organizers celebrated the continued success of ISBIS and ENBIS society, and the meeting draw together the international community of statisticians, both academics and industry professionals, who share the goal of making statistics the foundation for decision making in business and related applications. The Scientific Program Committee was constituted by: David Banks, Duke University Amílcar Oliveira, DCeT - Universidade Aberta and CEAUL Teresa A. Oliveira, DCeT - Universidade Aberta and CEAUL Nalini Ravishankar, University of Connecticut Xavier Tort Martorell, Universitat Politécnica de Catalunya, Barcelona TECH Martina Vandebroek, KU Leuven Vincenzo Esposito Vinzi, ESSEC Business Schoo

천연가스 액화 및 재기화 공정의 모형 및 최적 설계

학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부, 2014. 8. 한종훈.Natural gas is the worlds fastest-growing fossil fuel, favored for electric power and industrial sectors because of its low carbon intensity and reduced emissions. International natural gas trade is expected to double from 1 trillion cubic meter (tcm) in 2010 to 2 tcm in 2030. Liquefied natural gas (LNG) accounts for a growing share of world natural gas. The core of LNG value chain is the phase change of natural gas that makes it feasible for ship transportation to remote regions. This thesis addresses modeling and optimal design for LNG value chain and it contains two main processes: one is the liquefaction process in the production plant and the other is the regasification process in LNG receiving terminal. These two processes occupy the main parts in the whole in LNG value chain and are worth to be studied in depth. This thesis has five main parts. First, modeling and simulation of a liquefaction plant is conducted. Second part proposes a simulation-based optimization methodology, taking full advantage of commercial simulator in process design step. The methodology is applied to a case study of double-expander process optimization to prove its performance. A novel process design of natural gas liquefaction using nonflammable refrigerants is developed in the third part. Safety issue for floating LNG drives interest in minimization of hydrocarbon refrigerants. A new N2O-N2O-N2 cascade liquefaction process with nitrous oxide for the pre-cooling and condensation section and nitrogen gas for the sub-cooling section is proposed. Lastly, retrofit design scheme is introduced for boil-off gas handling process in LNG receiving terminal.Abstract i CHAPTER 1 : Introduction １ 1.1. Research motivation １ 1.2. Research objectives ３ 1.3. Outline of the thesis ４ CHAPTER 2 : Modeling and Simulation of Liquefaction Cycles [4] ５ 2.1. Introduction to LNG processing ５ 2.1.1. LNG value chain ５ 2.1.2. State of LNG industry ７ 2.1.3. Floating LNG ８ 2.2. Liquefaction Cycles ９ 2.2.1. Vapor compression refrigeration ９ 2.2.2. Gas refrigeration system １１ 2.2.3. Natural gas liquefaction processes １２ 2.3. Modeling and simulation １４ 2.3.1. Mathematical modeling １５ 2.3.2. Modeling and simulation using Aspen HYSYS® ２１ 2.3.3. Degree of freedom analysis ２４ CHAPTER 3 : Simulation-based optimization methodology for process design with case study of turbine-based liquefaction process ２８ 3.1. Introduction ２８ 3.2. Simulation-based optimization framework ３０ 3.3. Case study of natural gas liquefaction process ３５ 3.3.1. STEP 1: Base case design ３５ 3.3.2. STEP 2: Specifying the design variables ３５ 3.3.3. STEP 3: Optimization formulation ３５ 3.3.4. STEP 4: Providing additional constraints in the simulator ３８ 3.3.5. STEP 5: Determining the design space ３８ 3.3.6. STEP 6: Comprehensive simulation of the design space ４０ 3.3.7. STEP 7: Process mapping of the design space using empirical modeling ４０ 3.3.8. STEP 8: Empirical modeling validation ４１ 3.3.9. STEP 9: Optimization ４３ 3.4. Comparison with response surface methodology ４７ CHAPTER 4 : Natural gas liquefaction process design with nonflammable refrigerants for offshore application ５２ 4.1. Introduction ５２ 4.2. Thermodynamic analysis of carbon dioxide and nitrous oxide ５４ 4.3. Design of N2O-N2O-N2 cascade process ５７ 4.3.1. Pre-cooling section ５９ 4.3.2. Condensation section ６１ 4.3.3. Sub-cooling section ６３ 4.4. Results and discussion ６５ 4.5. Case study with a leaner feed gas ６９ CHAPTER 5 : Retrofit design of liquefied natural gas regasification process [79] ７２ 5.1. Introduction ７２ 5.2. Methodology ７７ 5.3. Case study ８０ 5.3.1. Base case design definition ８０ 5.3.2. Thermodynamic analysis of the base case design ８７ 5.3.3. Proposal of the retrofitting design for energy saving ８９ 5.3.4. Optimization of design variables ９５ 5.3.5. Design variables ９７ 5.4. Results and discussion １０３ 5.4.1. Comparison with the base design １０３ 5.4.2. Sensitivity analysis １０８ 5.4.3. Profitability of the proposed design １１５ CHAPTER 6 : Conclusion and Future Works １１７ 6.1. Conclusion １１７ 6.2. Future Works １１９ Literature Cited １２０ Abstract in Korean (요약) １３２Docto

Computer construction of experimental plans

Experimental plans identify the treatment allocated to each unit and they are necessary for the supervision of most comparative experiments. Few computer programs have been written for constructing experimental plans but many for analysing data arising from designed experiments. In this thesis the construction of experimental plans is reviewed so as to determine requirements for a computer program. One program, DSIGNX, is described. Four main steps in the construction are identified: declaration, formation of the unrandomized plan (the design), randomization and output. The formation of the design is given most attention. The designs considered are those found to be important in agricultural experimentation and a basic objective is set that the 'proposed' program should construct most designs presented in standard texts (e.g. Cochran and Cox (1957)) together with important designs which have been developed recently. Topics discussed include block designs, factorial designs, orthogonal Latin squares and designs for experiments with non-independent observations. Some topics are discussed in extra detail; these include forming standard designs and selecting defining contrasts in symmetric factorial experiments, general procedures for orthogonal Latin squares and constructing serially balanced designs. Emphasis is placed on design generators, especially the design key and generalized cyclic generators, because of their versatility. These generators are shown to provide solutions to most balanced and partially balanced incomplete block designs and to provide efficient block designs and row and column designs. They are seen to be of fundamental importance in constructing factorial designs. Other versatile generators are described but no attempt is made to include all construction techniques. Methods for deriving one design from another or for combining two or more designs are shown to extend the usefulness of the generators. Optimal design procedures and the evaluation of designs are briefly discussed. Methods of randomization are described including automatic procedures based on defined block structures and some forms of restricted randomization for the levels of specified factors. Many procedures presented in the thesis have been included in a computer program DSIGNX. The facilities provided by the program and the language are described and illustrated by practical examples. Finally, the structure of the program and its method of working are described and simplified versions of the principal algorithms presented