Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed June 11, 2007). PDF text: x, 153 p. : ill. UMI publication number: AAT 3243742. Includes bibliographical references. Also available in microfilm and microfiche formats.

A major characteristic of aircraft evolution is the rapid growth in the electrical and electronic content of each subsequenat ircraft generation.T he dominant technology used in an aircraft electrical power distribution network to switch power and to protect the aircraft wiring from hazardous electrical faults is the electro-mechanical relay switch and the electro-thermal circuit breaker. Despite the maturity of these devices they do however suffer from a number of problems relating to reliability, accuracy, and limited operational lifetime. The design, fabrication and testing of a novel Solid State Power Controller (SSPC) is described. The design uses power MOSFET's to provide both the power switching operation of a relay, and the power interruption capability of a circuit breaker. The majority of the control functions required by this device are performed digitally by virtue of a real time program executed on an embedded microcontroller. A number of methods are derived for characterising existing I2t wire protection trip response curves. Reproduction of a true 1 2t trip response in real time using iterative computational methods is described. An examination of the semiconductor thermal characteristics was undertaken. The methods adopted for extracting the power semiconductor thermal response involved direct measurement using infrared thermal imaging techniques and simulation using a computer based modelling tool. Knowledge of the semiconductor die temperature is of vital importance in the context of the overall protection strategy. A finite difference calculation performed in real time has been demonstrated as a viable method to predict the operational temperature of the MOSFET power switching devices used in the design

Orientador: Vivaldo Silveira Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T20:54:41Z (GMT). No. of bitstreams: 1 Makiyama_PatriciaAkemi_M.pdf: 5010847 bytes, checksum: 0e795746305d1a32f2e8979661b1f56c (MD5) Previous issue date: 2004 / Mestrado / Mestre em Engenharia de Alimentos

In this dissertation we present two techniques on the topic of digital interface design: a probabilistic timing verification and a timing analysis for synthesis, both rooted in a formal specification. Interface design arises when two digital components (e.g., a processor and a memory device) are to be interconnected to build up a system. We have extended a Petri net specification to describe the temporal behavior of the interface protocols of digital components. The specification describes circuit delays as random variables thus making it suitable to model process variations and timing correlation. Interface probabilistic timing verification checks that a subsystem, composed of components to be interconnected and the associated interface logic, satisfies the timing constraints specified by the components' specifications. Our verification technique not only yields tighter results than previous techniques that do not take timing correlation into consideration but also, if the timing constraint is not satisfied, determines the probability that a constraint will be violated. The second technique, timing analysis for synthesis, finds tight bounds on the delays of the interface logic, which are unknown prior to synthesis, such that all the timing constraints given in the component specifications are satisfied. / Graduate

<p>Redundant controllers are being designed to provide improved system reliability to meet the needs of various applications. In some implementations of these systems unacceptable system transients have occured when a single-controller failure occurs. The problem has been treated using case-by-case correction which is not sufficiently general in application to meet the needs of systems which may be user-programmed. Redundant control systems generalized as ideal and nonideal using two specific voting schemes are examined to gain insight into theoretical characterization of their performance under single-point failure modes and the limitations of applicability for the characterizations. State-model computer simulation is used to demonstrate the characterizations. A suggested direction for a general solution to the problem based on the chatacterizations is described.</p> / Master of Science

The advent of the VLSI technology makes it feasible to offer a once expensive system attribute called fault-tolerance to a wide variety of applications. This can be accomplished by using off-the-shelf single board computers and peripherals as the heart of the system. Custom design boards can then be added to meet the specific requirements of each application.

The overarching goal of this project is to develop intelligent, self-adapting numerical algorithms for the time discretization of complex real-world problems with Q-Learning methodologies. The specific application is ordinary differential equations which can resolve problems in mathematics, social and natural sciences, but which usually require approximations to solve because direct analytical solutions are rare. Using the traditional Brusellator and Lorenz differential equations as test beds, this research develops models to determine reward functions and dynamically tunes controller parameters that minimize both the error and number of steps required for approximate mathematical solutions. Our best reward function is based on an error that does not overly punish rejected states. The Alpha-Beta Adjustment and Safety Factor Adjustment Model is the most efficient and accurate method for solving these mathematical problems. Allowing the model to change the alpha/beta value and safety factor by small amounts provides better results than if the model chose values from discrete lists. This method shows potential for training dynamic controllers with Reinforcement Learning. / Master of Science / This research applies Q-Learning, a subset of Reinforcement Learning and Machine Learning, to solve complex mathematical problems that are unable to be solved analytically and therefore require approximate solutions. Specifically, this research applies mathematical modeling of ordinary differential equations which are used in many fields, from theoretical sciences such and physics and chemistry, to applied technical fields such as medicine and engineering, to social and consumer-oriented fields such as finance and consumer purchasing habits, and to the realms of national and international security and communications. Q-Learning develops mathematical models that make decisions, and depending on the outcome, learns if the decision is good or bad, and uses this information to make the next decision. The research develops approaches to determine reward functions and controller parameters that minimize the error and number of steps associated with approximate mathematical solutions to ordinary differential equations. Error is how far the model's answer is from the true answer, and the number of steps is related to how long it takes and how much computational time and cost is associated with the solution. The Alpha-Beta Adjustment and Safety Factor Adjustment Model is the most efficient and accurate method for solving these mathematical problems and has potential for solving complex mathematical and societal problems.

For about ten years, Texas Instruments has been developing a software environment of integrated tools for designing, debugging and documenting process control solutions that run on programmable controllers. The product - the Applications Productivity Tool (APT), allows process and control engineers to design and program in a graphical environment that compiles into machine code (relay ladder logic). APT is primarily targeted for the batch manufacturing industry in which engineers combine elements of both discrete and continuous control strategies. The objective of this research was to determine the applicability of APT in discrete parts manufacturing, using two applications of discrete manufacturing. One of these applications was a Fischertechnik model of a manufacturing system, configured to simulate the production of three distinct parts. The other application was the flexible manufacturing system being assembled in the Computer Integrated Manufacturing Laboratory (CIM Laboratory), which is equipped to produce models of a robot and a CNC milling machine. / Master of Science

An algorithm to design simple gain scheduled nonlinear PID controllers for nonlinear plants is investigated. Design information is obtained from measurements of the nonlinear plant about selected equilibrium points. Simulations are performed on two different nonlinear CSTR models. The first simulation produced an unexpected result: that linear output feedback performed better than state feedback for the particular model. The second simulation showed that the nonlinear PID controller performed as well as a complex nonlinear controller. A literature search for similar nonlinear controllers concluded that the nonlinear PID controller presented in this thesis did not provide a unified framework for previous work. / Master of Science

Syfte Vårt syfte med denna uppsats är att beskriva och förklara controllers olika roller i två stora företag som arbetar med sin controllerfunktion på olika nivåer. Vi vill skapa en fördjupad förståelse för controllerrollen och hur rollen påverkas av förväntningar från olika nivåer i företaget och controllerns position i företaget. Bakgrund Controllerrollen är under ständig förändring och det finns mycket forskning kring controllers. Det finns dock ett kunskapsgap som vi vill fylla när det gäller hur controllers roller påverkas utifrån förväntningar och position i företaget. Problemformulering Hur påverkar förväntningar och position i företaget controllers roller i ett företag? Metod Denna kvalitativa undersökning bygger på en induktiv ansats för att försöka fördjupa läsarens förståelse för området. Insamlade teorier och genomförda intervjuer tolkas genom ett hermeneutiskt synsätt. Vi har genomfört intervjuer på två stora svenska företag med sex olika controllers. Slutsats Varje controllerroll är unik och det är svårt att kategorisera controllers i bestämda fack. För varje controller som undersöks uppstår en ny kombination av controllerroller. Osäkerhet i rollen kan leda till att controllers tar hjälp av sin chef för att prioritera i sin roll. Överlag har controllers ingen formell beslutsmakt utan är indirekt aktiva i beslutsfattandet genom att ta fram beslutsunderlag, och besitter därigenom informell makt istället. Controllers roller påverkas även av ledningens tillit och graden av frihet som tilldelas controllern. Genom att controllers agerar flexibelt kan de motverka rolltvetydighet. Controllers påverkas även av var de är positionerad i företaget då de förväntas vara mest lojala mot den delen av organisationen de är anställda i. / Purpose Our purpose of this paper is to describe and explain the controllers different roles in two large companies who work with their controller function at various levels. We want to create a deeper understanding of controller roles and how the role is influenced by expectations from various levels of the company and the controller's position in the company. Background The controller role is constantly changing and there is much research on the controllers. However, there is a knowledge gap we want to fill in terms of how expectations and position in the company affects controllers roles. Research question How do expectations and position in the company affect controllers roles in a company? Methods This qualitative study is based on an inductiv approach to try to deepen the reader's understanding of the area. Collected theories and conducted interviews are interpreted by a hermeneutic approach. We conducted interviews at two large Swedish company with six different controllers. Conclusion Each controller role is unique and it is difficult to categorize the controllers in specific compartments. With every studied controller there is a new combination of controller roles. Insecurity in the role can result in controllers taking help of his boss to priority in their role. Overall, controllers have no formal power in decision making but is indirectly active in decision-making by providing decision basic data, and instead posses informal power in decision making. Controllers roles are also affected by the trust of the management and the degree of freedom controllers have been assigned. By acting flexible, controllers can work against role ambiguity. The position in the company also affects the controllers as they are expected to be most loyal to the part of the organization they are employed in.