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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Design and fabrication of novel microfluidic systems for microsphere generation

Song, Ki-Young 30 May 2011
<p>In this thesis, a study of the rational design and fabrication of microfluidic systems for microsphere generation is presented. The required function of microfluidic systems is to produce microspheres with the following attributes: (i) the microsphere size being around one micron or less, (ii) the size uniformity (in particular coefficient of variation (CV)) being less than 5%, and (iii) the size range being adjustable as widely as possible.</p> <p>Micro-electro-mechanical system (MEMS) technology, largely referring to various micro-fabrication techniques in the context of this thesis, has been applied for decades to develop microfluidic systems that can fulfill the foregoing required function of microsphere generation; however, this goal has yet to be achieved. To change this situation was a motivation of the study presented in this thesis.</p> <p>The philosophy behind this study stands on combining an effective design theory and methodology called Axiomatic Design Theory (ADT) with advanced micro-fabrication techniques for the microfluidic systems development. Both theoretical developments and experimental validations were carried out in this study. Consequently, the study has led to the following conclusions: (i) Existing micro-fluidic systems are coupled designs according to ADT, which is responsible for a limited achievement of the required function; (ii) Existing micro-fabrication techniques, especially for pattern transfer, have difficulty in producing a typical feature of micro-fluidic systems - that is, a large overall size (~ mm) of the device but a small channel size (~nm); and (iii) Contemporary micro-fabrication techniques to the silicon-based microfluidic system may have reached a size limit for microspheres, i.e., ~1 micron.</p> <p>Through this study, the following contributions to the field of the microfluidic system technology have been made: (i) Producing three rational designs of microfluidic systems, device 1 (perforated silicon membrane), device 2 (integration of hydrodynamic flow focusing and crossflow principles), and device 3 (liquid chopper using a piezoelectric actuator), with each having a distinct advantage over the others and together having achieved the requirements, size uniformity (CV ⤠5%) and size controllability (1-186 &#x00B5;m); (ii) Proposing a new pattern transfer technique which combines a photolithography process with a direct writing lithography process (e.g., focused ion beam process); (iii) Proposing a decoupled design principle for micro-fluidic systems, which is effective in improving microfluidic systems for microsphere generation and is likely applicable to microfluidic systems for other applications; and (iv) Developing the mathematical models for the foregoing three devices, which can be used to further optimize the design and the microsphere generation process.</p>
12

Finite Bargaining Problems

Wu, Hanji 15 May 2007 (has links)
Bargaining is a process to decide how to divide shared resources between two or more players. And axiomatic bargaining specifies desirable and simple properties the outcome of the bargaining should satisfy and identifies the solution that produces this outcome. This approach was first developed by John Nash in his seminal work(Nash 1950). Since then, numerous studies have been done on bargaining problems with convex feasible set or with non-convex but comprehensive feasible set. There is, however, little work on finite bargaining problems. In this dissertation, we study finite bargaining problems systematically by extending the standard bargaining model to the one consisting of all finite bargaining problems. For our bargaining problems, we first propose the Nash, Maximin, Leximin, Maxiproportionalmin, Lexiproportianlmin solutions, which are the counterparts of those that have been studied extensively in both convex and non-convex but comprehensive problems. We then axiomatically characterize these solutions in our context. We next introduce two new solutions, the maximin-utilitarian solution and the utilitarian-maximin solution, each of which combines the maximin solution and utilitarian solution in different ways. The maximin-utilitarian solution selects the alternatives from the maximin solution that have the greatest sum of individuals’ utilities, and the utilitarian-maximin solution selects the maximin alternatives from the utilitarian solution. These two solutions attempt to combine two important but very different ethical principles to produce compromised solutions to bargaining problems. Finally, we discuss several variants of the egalitarian solution. The egalitarian solution in finite bargaining problems is more complicated than its counterpart in either convex or non-convex but comprehensive bargaining problems. Given its complexity in our context, we start our inquiry by investigating two-person, finite bargaining problems, and then extend some of the analysis to n-person, finite bargaining problems. Our analysis of finite bargaining problems and axiomatic characterizations of the extensions of various standard solutions of convex/non-convex but comprehensive bargaining problems to finite bargaining problems will shed new light on the behavior of these solutions. Our new solutions will expand our understanding of the bargaining theory and distributive justice from a different perspective.
13

Design and fabrication of novel microfluidic systems for microsphere generation

Song, Ki-Young 30 May 2011 (has links)
<p>In this thesis, a study of the rational design and fabrication of microfluidic systems for microsphere generation is presented. The required function of microfluidic systems is to produce microspheres with the following attributes: (i) the microsphere size being around one micron or less, (ii) the size uniformity (in particular coefficient of variation (CV)) being less than 5%, and (iii) the size range being adjustable as widely as possible.</p> <p>Micro-electro-mechanical system (MEMS) technology, largely referring to various micro-fabrication techniques in the context of this thesis, has been applied for decades to develop microfluidic systems that can fulfill the foregoing required function of microsphere generation; however, this goal has yet to be achieved. To change this situation was a motivation of the study presented in this thesis.</p> <p>The philosophy behind this study stands on combining an effective design theory and methodology called Axiomatic Design Theory (ADT) with advanced micro-fabrication techniques for the microfluidic systems development. Both theoretical developments and experimental validations were carried out in this study. Consequently, the study has led to the following conclusions: (i) Existing micro-fluidic systems are coupled designs according to ADT, which is responsible for a limited achievement of the required function; (ii) Existing micro-fabrication techniques, especially for pattern transfer, have difficulty in producing a typical feature of micro-fluidic systems - that is, a large overall size (~ mm) of the device but a small channel size (~nm); and (iii) Contemporary micro-fabrication techniques to the silicon-based microfluidic system may have reached a size limit for microspheres, i.e., ~1 micron.</p> <p>Through this study, the following contributions to the field of the microfluidic system technology have been made: (i) Producing three rational designs of microfluidic systems, device 1 (perforated silicon membrane), device 2 (integration of hydrodynamic flow focusing and crossflow principles), and device 3 (liquid chopper using a piezoelectric actuator), with each having a distinct advantage over the others and together having achieved the requirements, size uniformity (CV ⤠5%) and size controllability (1-186 &#x00B5;m); (ii) Proposing a new pattern transfer technique which combines a photolithography process with a direct writing lithography process (e.g., focused ion beam process); (iii) Proposing a decoupled design principle for micro-fluidic systems, which is effective in improving microfluidic systems for microsphere generation and is likely applicable to microfluidic systems for other applications; and (iv) Developing the mathematical models for the foregoing three devices, which can be used to further optimize the design and the microsphere generation process.</p>
14

How to approximate the naive comprehension scheme inside of classical logic

Weydert, Emil. January 1989 (has links)
Thesis (doctoral)--Universität Bonn, 1988. / Includes bibliographical references.
15

AXIOMATIC DESIGN OF BEARING PACKAGING AUTOMATION

2014 January 1900 (has links)
QA bearing technologies Ltd. (hereafter QA) is a custom manufacturer of bearings in a variety of types and sizes. This research concerns one of the processes in QA’s bearing manufacturing in which the individual bearings, once assembled, are packaged to prevent corrosion and attack from any environmental influence. QA currently employs a manual process, which is time-consuming and significantly limits QA’s productivity. This greatly raises a need to improve this process through the design of an automated process for bearing packaging. Various kinds of packaging machine are available in the market for this application. However, most of them are designed for general packaging purpose and simply combining them may result in the functional overlap as applied to the packaging process. This research aims to design an automatic bearing packaging system (ABPS) based on an advanced design theory, i.e., Axiomatic Design Theory (ADT). In the first part of this research, a set of general functional requirements (FRs) and constraints (CONs) were defined specifically based on the needs from the customers. All FRs were maintained independent to each other such that the following design wouldn’t result in functional overlap. Then, design parameters (DPs) in general level were created to satisfy the defined FRs, each being a functionally independent subsystem consists of both custom-design components and products existing in the market. The second part of the research was to decompose the FRs and DPs based on independent axiom of ADT into further levels until the conceptual design was accomplished. In this process, acceptable alternatives in different hierarchies were proposed for comparison in the decision making process. Also, the relationship between FRs and DPs in the same level was always maintained one-to-one, which allows readily for modification in future, if needed. In the third part of this research, the information axiom of ADT was utilized to find the best solution from alternatives. For this, each alternative was evaluated in terms of the information content that reflects the possibility of satisfying the objective FR. The one with least information content was determined as the best alternative. As a result of this research, two solutions with different degree of automation were recommended for the bearing packaging system. The first solution is featured with higher degree of automation and capable of packaging bearings with limited human interface and as result, the total cost for its implementation is relatively high. The second solution integrates semi-automated machines and simplified sealing strategy and as such, the cost for its implementation is significantly reduced. After the conceptual design is complete, ADT is further applied in the detailed design level for oiling system with custom-designed components and mechanism. For the design of certain DPs, the design process applying ADT is used to compare with conventional methods, proved to be more efficient and simplified. Eventually, the final solution proposed for the detailed design of oiling system is consistent with independent axiom of ADT.
16

Truth, deflationism and the ontology of expressions : an axiomatic study

Nicolai, Carlo January 2014 (has links)
Philosophical enquiry on the notion of truth has traditionally involved the identification of a class of objects to which truth is ascribed. At the same time, formal investigations are often required when the notion of truth is at issue: semantic paradoxes force in fact philosophers to shape their arguments in a precise way. Objects of truth, in formal context, are always reduced to other, more manageable objects that mimic their structural properties such as numbers or sets. This form of reduction renders the distinction between linguistic or syntactic objects, to which truth is usually applied, and their mathematical counterparts opaque, at least from the point of view of the theory of truth. In informal metatheoretic discussion, in fact, they are clearly different entities. In this thesis we focus on an alternative way of constructing axiomatic theories of truth in which syntactic objects and mathematical objects belong to different universes. A brief introduction tries to situate the proposed theories in the context of different investigations on axiomatic truth. Chapter 2 is devoted to the discussion of historical and more theoretical motivations behind the proposed alternative. Chapter 3 will present the syntactic koinè spoken by our theories. Morphological categories of the object language and logical concepts concerning the object theory will be formalised in a recent axiomatisation of hereditarily finite sets. In Chapter 4 we finally introduce theories of truth with a built-in syntactic theory and examine some of their consequences. We briefly focus on disquotational truth, then consider compositional axioms for truth. Chapter 5 investigates a possible application of the setting just introduced: a realisation of the all-present interaction, in metamathematical practice, between informal metatheoretic claims and their (suitably chosen) coded counterparts. In the final chapter, after a brief characterisation of the key doctrines of the delflationary conception of truth, we evaluate the impact that the theories of truth studied in this work can have on the debate on the so-called conservativeness argument, which tries to match the alleged insubstantiality of the notion of truth, advocated by deflationists, with the deductive power of deflationary acceptable theories of truth.
17

On Mothodological Approach to Philosophical System of Sunology

Jiang, Chunqi 04 July 2001 (has links)
On Mothodological Approach to Philosophical System of Sunology Abstract A Study on the Methodology of the Philosophical System of Sunology The focus of this doctoral dissertation is primarily predicated upon my attempt to explore the philosophical system of Sunology or Dr. Sun Yat-sen¡¦s works and the related mode and value of the methodology. As a consequence of this effort, this author suggests a common foundation of research and dialogue as a model for human epistemology. With this foundation in mind, the main dimensions of Sunology has been explored: (1) Regarding the philosophical system, the method of content analysis in social sciences has been applied, yielding its peculiar characteristics and mode; (2) Regarding its logical structure, the axiomatic method has been employed so as to testify that Dr. Sun¡¦s logical structure is well integrated; (3) Regarding Dr. Sun¡¦s operational dimension, the mode of interdisciplinary integration has been used, so as to clarify his operational conversion; and (4) Regarding Sunology¡¦s consistency in its logic, an attempt has been made to explore its methodology, so as to find out its form and value and, at the same time, the kind of method and approach to materialize an ideal. From the study, one should realize that mankind ought to seriously weigh the value of any given theoretical and philosophical systems in the past and fully appreciate its latent significance and validity. As a next step, one should try to put it into practice. Subsequently, an attainable framework should be constructed, so as to fulfill the projected undertaking. However, we should understand that the approach and method should not be just limited to this. At the same time, it should be noted that our framework argues that knowledge has a holistic structure which can be mutually continuous. Philosophical systems are interrelated. When analyzing any change in the relationship and its development, it is necessary to clarify the structure and operation aspects of the two. Only having done that, can we enhance the clarification and systematization of thinking. And only then, can we handle humankind and nature¡¦s mutual movement. Unless this is done, it is not possible for us to have an original look at human thinking and knowledge construction. In this connection, it should be noted that each discipline has its background and knowledge. Based on this, can we develop pervasive and automatic mode of knowledge. After that, can we have the ability to be creative. As a result, human knowledge and culture can continue its integrative process and be progressive.
18

Testing the effects of violating component axioms in validation of complex aircraft systems

Kansal, Aparna 12 January 2015 (has links)
This thesis focuses on estimating faults in complex large-scale integrated aircraft systems, especially where they interact with, and control, the aircraft dynamics. A general assumption considered in the reliability of such systems is that any component level fault will be monitored, detected and corrected by some fault management capability. However, a reliance on fault management assumes not only that it can detect and manage all faults, but also that it can do so in sufficient time to recover from any deviation in the aircraft dynamics and flight path. Testing for system-level effects is important to ensure better reliability of aircraft systems. However, with existing methods for validation of complex aircraft systems, it is difficult and impractical to set up a finite test suite to enable testing and integration of all the components of a complex system. The difficulty lies in the cost of modelling every aspect of every component given the large number of test cases required for sufficient coverage. Just having a good simulator, or increasing the number of test cases is not sufficient; it is also important to know which simulation runs to conduct. For this purpose, the thesis proposes simulating faults in the system through the violation of “axiomatic conditions” of the system components, which are conditions on the functioning of these components introduced during their development. The thesis studies the effect, on the aircraft dynamics, of simulating such faults when reference models of the components representing their key functions are integrated.
19

Essays on commitment and flexibility

Payro Chew, Fernando 30 October 2021 (has links)
This dissertation consists of two essays studying economic agents who choose menus, or opportunity sets from which they will make a choice at a later date. The common theme is that the utility of a menu can be affected by inclusion of alternatives that are not subsequently chosen. This effect can create either a preference for commitment or a preference for flexibility. The first essay models an agent who experiences temptation when choosing from a menu of lotteries, and who is self-aware and anticipates her future behavior when choosing between menus. Her desire to eliminate tempting alternatives from a menu creates a preference for commitment. When studying menus of lotteries, the literature has typically assumed that preferences satisfy the Independence axiom. Independence requires that the ranking of two menus is not affected if each is mixed (probabilistically) with a common third menu. In particular, the preference for commitment is invariant under Independence. This essay argues that intuitive behavior may require that the preference for commitment be affected by such mixing, and hence be mixture-dependent. To capture such behavior, a generalization of the temptation and self-control model of Gul and Pesendorfer (2001) is provided. The model generalizes Gul and Pesendorfer (2001) by replacing their Independence axiom with a suitably adapted version of the Mixture-Betweenness axiom of Chew (1989) and Dekel (1986). The result is an implicit utility model in which utility is defined as the unique solution of an equation that depends on the agent's commitment and temptation rankings, neither of which needs to satisfy the Independence axiom. Axiomatic characterization of the model exploits a novel extension of the Mixture Space Theorem to preferences that satisfy Mixture-Betweenness. Since the Mixture Space Theorem is central to decision theory, this extension is potentially useful for addressing issues in economics other than temptation and self-control. The second essay explores the testable implications of the linear representations considered in Dekel et al. (2001). Dekel et al. (2001) extends the seminal model of preference for flexibility due to Kreps (1979) by considering menus of lotteries rather than deterministic alternatives. They show that a simple set of axioms characterizes a representation that can be interpreted as if the agent is uncertain about her future tastes. This taste uncertainty is summarized by the “subjective state space”, consisting of the set of possible future preferences over lotteries. Their approach is axiomatic, thus testability requires that the entire preference order be observable. This essay provides a corresponding revealed preference analysis and assumes that only finitely many choices are observed. It is shown that for a particular class of data sets, the characterizing conditions can be reformulated as nonlinear systems of inequalities for which the existence of solutions can be verified using numerical methods. Hence, for this type of data, the analysis provides a test for the subjective state space hypothesis that is, in principle, implementable. In addition, the analysis covers the case where available data involves only menus of alternatives (and not lotteries). Hence, it also provides revealed preference characterizations for Kreps (1979).
20

Deontic Action Logics for Specification and Analysis of Fault-Tolerance

Castro, Pablo F. January 2009 (has links)
<p> In this thesis we develop a mathematical framework to express and reason about properties of fault-tolerant computing systems. The main idea behind this mathematical framework is to use axiomatic theories to specify systems. The standard logical operators allow us to describe the basic behavior of the system, while we use deontic predicates on actions to express prescriptions about the system's behavior. Deontic logics have proved to be useful for reasoning about legal and moral systems, where the situation is more or less similar to fault-tolerance: there exists a set of rules that states what the normal behaviours or scenarios are. Violations arise when these rules are not followed and, as a consequence, some actions must be performed to return to a normal or desirable state. We develop our own deontic logic, keeping in mind that we want to use it for specifying fault-tolerant systems. We investigate the properties of this logic, commenting on those that are relevant to the use of the logic in practice. We provide two different deductive systems; one of them is a standard (Hilbert style) deductive system, while the other one is a tableaux system, which can be applied automatically to prove properties of specifications.</p> <p> In any specification language, it is important to have at hand mechanisms which enable designers to modularize the system description; we investigate how to apply these mechanisms to the logics proposed in this thesis, and, in particular, we focus on how the modularization of specifications affects the local prescriptions of a module (or component). We study the problems that arise from the interaction between components. We show that, in some cases, we can guarantee that the locality of violations in a particular component is preserved. Some examples are provided throughout this thesis to illustrate how the ideas described below can be applied in practice. </p> / Thesis / Doctor of Philosophy (PhD)

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