The manufacturing process has been a heavily studied area over the past century. The study completed herein has established a foundation for the future of manufacturing research. The next step of this industry is to become proficient at the micro and nano scale levels of manufacturing. In order to accomplish this goal, the modeling of machining system needs to be completely understood throughout the entire process. In effort to attack this problem, this study will focus on the boundaries present in machining systems; and will define and interpret the associated phenomena. This particular focus is selected since nearly all manufacturing related studies concentrate on continuous processes; which by definition considers only one particular operation. There is a need to understand the phenomena corresponding to interactions of multiple processes of manufacturing systems. As a means to this end, the nonlinear phenomena associated in the continuous domains of machining systems will be modeled as linear to ensure the boundary interactions are clearly observed. Interference of additional nonlinearities is not the focus of this research. In this dissertation, the mechanical model for a widely accepted machine-tool system is presented. The state and continuous domains are defined with respect to the boundaries in this system (contact and frictional force acting at the point of tool and work-piece contact). The switching sets defining plane boundaries for the continuous systems of this machine-tool will be defined and studied herein. The forces and force products, at the point of switching from one continuous system to another, govern the pass-ability of the machine-tool through the respective boundary. The forces and force product components at the switching points are derived according to discontinuous systems theory Luo [1]. Mapping definitions and notations are developed through the switching sets for each of the boundaries. A mapping structure and notation for periodic interrupted cutting, non-cutting and chip seizure motions are defined. The interruption of the chip flow for a machining system will be investigated through a range of system parameters. The prediction of interrupted periodic cutting, non-cutting and chip seizure motion will be completed via closed form solutions for this machine-tool. The state of this system is defined to utilize the theory of Luo [1]. This is necessary to properly handle the frictional force boundary at the chip/tool interface, the onset of cutting boundary and the contact boundary between the tool and work-pieces. The predictions by this method will be verified via numerical simulation and comparison to existing research. A goal of this research is to illustrate the effects of the dynamical systems interacting at the frictional force (chip/tool) boundary and the chip onset of growth and vanishing boundary. The parameter space for this machine-tool model is studied through numerical and analytical predictions, which provide limits on the existence of interrupted periodic cutting, non-cutting and chip seizure motions.

The effects of abrasive particle size and tool surface roughness on tool and work wears of a polishing process were investigated. It was aimed to obtain a polishing condition that could result in a high work wear while the tool wear was low. An analytical study was first done to examine how the various operating conditions affected the wear rates of tool and work. It was done from a wear model developed by Su and Horng [1]. This model was further extended in the study to allow the wear rate analysis for an abrasive particle with ellipsoid shape. It was shown that an enhancement of abrasive particle size or tool surface roughness would increase the work wear while decrease the tool wear. Several sets of experiments were conducted to confirm the predictions of analytical study. It was shown that the experimental trends were the same as the analytical ones. Finally, the possible causes of observed phenomena and the limitations of the study were discussed.

Knowledge is an increasingly important asset for organizational competition. In order to manage organizational knowledge effectively, document management is the first step. Therefore, how to manage organizational documents is an issue of interest to many enterprises. In order to manage documents effectively on the computer, it is necessary to understand the content of these documents, which needs a clear description of the included concepts. Ontology is a method for describing concepts and their relations and the metadata of factual data to help users understand the knowledge in a document. Ontology can also be a bridge for knowledge exchange between the user and the computer. Therefore, the construction of ontology is important for knowledge and document management. This research proposes a method for the construction of event ontology, which can be used to construct the ontology of an event. The method includes text pre-processing and event ontology construction. Test pre-processing module includes POS tagger, word filter, and term analysis. Event ontology module provides a friendly editing environment for the user to build the concepts and attributes of an event to provide the ontology of ¡§who,¡¨ ¡§what,¡¨ ¡§where,¡¨ and ¡§what object.¡¨ To verify the feasibility of the proposed method, a prototype system for ontology construction is built. The Alexander Poison Event was used as an example to demonstrate the value of the prototype system.

Magnetic Resonance Spectroscopy (MRS) can be applied to probe noninvasively the concentrations and distribution of metabolites of human tissue in vivo. As the improving of hardware and localization techniques, MRS becomes more and more important in clinical applications. Furthermore, some post-processing software, like LCModel, provide a graphical user interface for efficient and convenient analysis of MR spectroscopic imaging and thus increase the value of MRS applications. Although LCModel provides an efficient analysis and produces stable results, it can not provide metabolite map to observe the distribution of metabolite concentrations. For this reason our study processes the output data of LCModel and Digital Imaging and Communications in Medicine (DICOM) format MR images for 2D/3D metabolite map displaying. Users can use this software to observe the metabolic distribution in AP, SI and RL slice of brain tissue. In the meanwhile, as the absolute quantification of MRS has played more and more important role in clinical applications, this study also provides the LCModel end users an easy way for interpretation.

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My research is about monitoring the software development process to assess Capability maturity level. Capability Maturity Model (CMM) was developed to improve the software process based on subjective assessment by teams of experts. We propose an objective CMM assessment, which replaces expensive and time-consuming human effort by a knowledge-based system. Compared to Subjective CMM assessment, Objective CMM assessment can be less expensive, takes less time, and is easy to estimate the software development environment maturity. The accuracy of Objective CMM assessment can be the same as Subjective CMM assessment if enough activities are represented as objective activities. For example, if subjective activities total 80 % and objective activities total 20 %, then the accuracy of Objective CMM assessment is not reliable. It would be reliable if the objective activity is increased up to 80% from 20%. This dissertation presents how to change from Subjective CMM assessment to Objective CMM assessment, and we will prove that Objective CMM Assessment is effective.

This dissertation focuses on developing algorithms that generate tool paths for free-form surfaces based on accuracy of desired manufactured part. A manufacturing part is represented by mathematical curves and surfaces. Using the mathematical representation of the manufacturing part, we generate reliable and near optimal tool paths as well as cutter location (CL) data file for postprocessing. This algorithm includes two components. First is the forward-step function which determines maximum distance called forward- step between two cutter contact (CC) points with given tolerance. This function is independent of the surface type and is applicable to all continuous parametric surfaces that are twice differentiable. The second component is the side-step function which determines maximum distance called side-step between two adjacent tool paths with a given scallop height. This algorithm reduces manufacturing and computing time as well as the CC points while keeping the given tolerance and scallop height in the tool paths. Several parts, for which the CC points are generated using the proposed algorithm, are machined using a three axes milling machine. As part of the validation process, the tool paths generated during machining are analyzed to compare the machined part and the desired part.

In this study, an electrolytic micro-machining tester is employed to investigate the effects of supply voltage,electrode gap and initial machining position on the geometry of the tungsten needle. The tungsten needle to be electrolyzed is dipped in an aqueous electrolyte of 2wt % sodium hydroxide as the anode, and the stainless steel needle with a diameter of 50 £gm as the cathode(tool electrode), and the electrode gap is set to be 30 £gm.Morever,the tungsten needle can be allowed to be fixed or in the reciprocating motion. Experimental results show that when the tip diameter of stainless steel needle is less than 50 £gm, a great quantity of current density and power are generated to cause the temperature failure of the tool electrode. At a certain gap between the electrodes, the electric field is focused on the narrow range to improve its processing efficiency. Under the higher supply voltage condition, it is difficult to control the size because the diameter of tungsten rod is reduced very quickly. Under the lower supply voltage condition, the diameter of tungsten rod can be processed to smaller sizes, but it takes a long time. Therefore, in the beginning of the experiment, the tungsten rod is electrolyzed under a higher voltage to the small size, and then the supply vltage is switched to lower value to conduct the electrolysis process. Consequently, a finer and more even tungsten needle can be obtained. Experimental results show that a more even tungsten needle with the length of 600 £gm and the diameter of 4 £gm can be manufactured.

<p>Many maintenance policies have been proposed for refreshing a warehouse. The difficulties of selecting an appropriate maintenance policy for a specific scenario with specific source characteristics, user requirements etc. has triggered researcher to develop algorithms and cost-models for predicting cost associated with a policy and a scenario. In this dissertation, we develop a benchmarking tool for testing scenarios and retrieve real world data that can be compared against algorithms and cost-models. The approach was to support a broad set of configurations, including the support of source characteristics proposed in [ENG00], to be able to test a diversity set of scenarios.</p>