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A particular problem that has been encountered in modelling the forces and moment acting on a manoeuvring ship, has been the correct estimation of the distribution of side force along its length. If traditional slender body theory is used, reasonable agreement can be obtained between theoretical and experimental result over the forebody of the ship. However, moving aft, the two increasingly diverge until there are significant differences at the stem. For this reason manoeuvring coefficients cannot be accurately predicted by this approach. In a number of studies, the reason for the discrepanciesh as been attributed to the influence of trailing vortices that develop along the hull. The conclusion is consistent with sensitivity analyses carried out with augmented slender body theory incorporating vortices of specified location and strength along the ship. The present thesis is concerned with modelling trailing vortices along a ship in drift motion so that they can be used in the calculation of the associated distribution of forces and manoeuvring coefficients. A numerical model based on the Discrete Vortex Method has been developed for the analysis of vortex flow around the ship which is representedb y slender body approximation. The trailing vortices are modelled by a series of transverse two-dimensional multi-vortex solutions marching longitudinally down the hull. Results are presented for six different hull types; a flat plate, the Wigley hull, a block hull, a Series 60 hull, the British Bombardier and the British Bombardier with a pram stem. The effects of varying drift angles are also investigated for each hull types. Good qualitative agreement is shown between the predicted velocity and vorticity fields and results from experimental studies. The distribution of side forces and yaw moments along the hull is also well predicted. The results explain manoeuvring phenomena occurring for the hull forms considered that have been observed experimentally and at full scale.

This thesis explores ways in which the outsider questions rather than confirms dominant cultural values whilst avoiding the crudity of overt politicisation. I argue that the outsider's preference for an observer's stance is not so much an act which denies responsibility to the world of his day, but rather a means of reassessing its priorities. In Section One, I discuss Conrad's role as an outsider in the age of Empires. I demonstrate the ways in which Conrad employs narrators, frequently using strategies of irony which can be and have been read in very different ways. I argue that Conrad uses irony as a tool for condemnation rather than condonement of imperialist practice, if not its ideology. In Section Two, I discuss Lowry as an emigre from England (so contrasting him with Conrad, the immigrant from Europe), and examine his dissenting voice which opposes bourgeois prejudice against the working class, a totalising ideology like Fascism, and a Western rationalism which sees too rigid a distinction between sanity and madness. I demonstrate how Lowry as an outsider reacts to the age of twentieth century World Wars. In Section Three, I discuss Naipaul's role as an outsider in the age of decolonisation, when bogus liberals and false redeemers fail to rebuild the newly independent post-colonial states. As in Conrad's case, I show how a failure to read Naipaul's ironic tone of voice has given rise to radically divergent views as to what he is about. I also link Conrad and Naipaul through their cultural negotiation between the 'centre' and its peripheries. By looking at these three writers in chronological order and offering a comparative perspective on their work, I highlight the outsider's disturbing, yet illuminating role within a historical context. I also draw attention to creative tensions between artistic concerns and a serious political purpose. I assess the outsider as observer and man of conscience rather than as a` mere onlooker. I conclude that the outsider also fulfils a social obligation by promoting critical awareness on the reader's side by means of his defamiliarising perspective.

The increasing popularity of Social Reference (SR) services has enabled a corresponding growth in the number of users engaging in them as well as in the number of questions submitted to the services. However, the efficiency and quality of the services are being challenged because a large quantity of the questions have not been answered or satisfied for quite a long time. In this dissertation project, I propose using expert finding techniques to construct an automated Question Triage (QT) approach to resolve this problem. QT has been established in Digital Reference (DR) for some time, but it is not available in SR. This means designing an automated QT mechanism for SR is very innovative. In this project, I first examined important factors affecting triage decisions in DR, and extended this to the SR setting by investigating important factors affecting the decision making of QT in the SR setting. The study was conducted using question-answer pairs collected from Ask Metafilter, a popular SR site. For the evaluation, logistic regression analyses were conducted to examine which factors would significantly affect the performance of predicting relevant answerers to questions. The study results showed that the user's answering activity is the most important factor affecting the triage decision of SR, followed by the user's general performance in providing good answers and the degree of their interest in the question topic. The proposed algorithm, implementing these factors for identifying appropriate answerers to the given question, increased the performance of automated QT above the baseline for estimating relevant answerers to questions. The results of the current study have important implications for research and practice in automated QT for SR. Furthermore, the results will offer insights into designing user-participatory DR systems. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

This dissertation study is a longitudinal qualitative investigation of how graduate students in a social science field construct their professional identity. Among the different identities that individuals construct and have imposed upon them, their professional identity may be more distinct as compared to other identities such as gender roles, position of caretaker, and ethnicity that may develop over a longer period of time and be more diffuse. One’s professional identity is likely to become a central identity because it provides agency, power, and a socially respected position in a particular disciplinary field and in society at large. This investigation of graduate students’ disciplinary development was designed to contribute to a better understanding of the process of professional identity development. Doctoral students in a social science field were chosen as participants because they were likely to undergo intensive identity construction processes in a short time period of time. In this staggered longitudinal study, the total number of participants was 34. Participants were tracked across milestones over at least two semesters of their program. Data collection included multiple interviews, member checking, and observation of students’ activities in content classes, research meetings, social gatherings, and professional conference participation according to distinct stages that occur over time. Analyzed using grounded theory methodology, data are presented in three themes representing significant influences on professional identity development. For the first theme, graduate students’ professional identity seemed to progress through phases marked by milestones. In Theme 2, graduate students’ professional identity seemed to develop through interactions with other individuals in several learning communities. In Theme 3, graduate students seemed to forge their professional identity through their program experiences, defining their professional self as the acquisition of self-knowledge and self-regulation skills (being professional), disciplinary knowledge and skills (being a professional), and envisionment of a professional future self participating in a community of practice. Development of professional disciplinary skills including disciplinary discourse practices appeared as a core contributor for students’ professional identity development. Generalizable professional skills seemed more subtle and foundational for the other two factors (professional skills acquisition and professional affiliation). Individuals who developed both professional skills and professional affiliation seemed to have a strong professional identity. In addition, data indicated that as graduate students underwent the professional identity process, they seemed more motivated to take up their academic responsibilities and participate in their professional field. In sum, the contribution of this study is that different influences on graduate students’ professional identity development were shown, and a clearer view of the overall professional identity development process was obtained, including what factors are influencing graduate students’ professional identity development as well as their possible future self in their disciplinary community of practice.

This study highlights how graduate studies involve students in building their professional identity by social roles, positions, and discourse skills in the process of professional training. The research question addressed in this study is whether the new roles and situations encountered by graduate students bring constraints and expectations. I was hoping to contribute to the literature on understanding how graduate students build new identities as researchers, and at a more theoretical level, to developing insight into the connection between identity and professional identity construction. The result presented as the central phenomenon of a grounded theory model, professional disciplinary enculturation was influenced by previous job and education experiences and current academic and personal relationships. The disciplinary training influenced by coursework, and research and writing projects seemed to support the students’ identity development, even as the enculturation process was experienced as emotionally taxing to different degrees and required the (re)shaping of identity and discourse practices.

The ability to navigate in everyday environments is a fundamental and necessary skill for any autonomous mobile agent that is intended to work with human users. The presence of pedestrians and other dynamic objects, however, makes the environment inherently dynamic and uncertain. To navigate in such environments, an agent must reason about the near future and make an optimal decision at each time step so that it can move safely toward the goal. Furthermore, for any application intended to carry passengers, it also must be able to move smoothly and comfortably, and the robot behavior needs to be customizable to match the preference of the individual users. Despite decades of progress in the field of motion planning and control, this remains a difficult challenge with existing methods. In this dissertation, we show that safe, comfortable, and customizable mobile robot navigation in dynamic and uncertain environments can be achieved via stochastic model predictive control. We view the problem of navigation in dynamic and uncertain environments as a continuous decision making process, where an agent with short-term predictive capability reasons about its situation and makes an informed decision at each time step. The problem of robot navigation in dynamic and uncertain environments is formulated as an on-line, finite-horizon policy and trajectory optimization problem under uncertainty. With our formulation, planning and control becomes fully integrated, which allows direct optimization of the performance measure. Furthermore, with our approach the problem becomes easy to solve, which allows our algorithm to run in real time on a single core of a typical laptop with off-the-shelf optimization packages. The work presented in this thesis extends the state-of-the-art in analytic control of mobile robots, sampling-based optimal path planning, and stochastic model predictive control. We believe that our work is a significant step toward safe and reliable autonomous navigation that is acceptable to human users.

The goal of this thesis is to investigate metal structures for photonics and plasmonics and to provide theoretical and experimental bases for their practical applications. Engineered micro- and nanostructures of a metal can efficiently manipulate surface plasmon polaritons (SPPs) - coupled photon-electron waves propagating along a metal-dielectric interface. Since SPPs are able to contain both characteristics of light and charge, exploiting SPPs can lead to novel optical behaviors, for example, concentration of light below the optical diffraction limit, generating large electric-field enhancements in confined regions. This unique characteristic of SPPs has opened up new opportunities for photonic and plasmonic applications such as surface-enhanced spectroscopy, subwavelength waveguides, optical antennas, solar cells, and thermophotovoltaics. However, while many fabrication techniques have been developed and utilized to prepare metal structures, some applications would still benefit from improved methods because SPPs are extremely sensitive to inhomogeneities on a metallic surface arising from roughness, impurities and even grain boundaries of a metal. To minimize the surface inhomogeneities of the metal structures and thus to exploit SPPs effectively, we introduced novel fabrication methods. First, the template-stripping method was employed to obtain high-quality silver films for SPPs in the visible wavelengths. The template-stripped films showed very smooth surfaces, leading to the improved dielectric function with high electrical conductivity and low optical loss. The dielectric function of the template-stripped films was compared with that of conventional films. As a result, the relation between the surface roughness and dielectric function of metal films could be derived. As another approach to reduce the inhomogeneities on a metal surface, we prepared single-crystalline silver films via epitaxial growth. Under controlled deposition conditions, single-crystalline silver films exhibited ultrasmooth surfaces with a root mean square roughness of 0.2 nm. Moreover, we observed that the absence of the grain boundaries can lead to an increase in SPP propagation length as well as precise patterning for metal structures. Beyond noble metals, we then introduced an effective route to obtain smooth patterned structures of refractory metals, semiconductors, and oxides via template stripping. The smooth structures of such materials can be favorable for many applications including thermal emitters, metamaterials, solar absorbers, and photovoltaics. We demonstrated that a variety of desired materials deposited on a thin noble metal layer can be peeled from silicon templates. After removing the noble metal layer, the revealed surfaces had very small roughness. This approach could easily reproduce structures via reuse of templates, leading to a low-cost and high-throughput process in micro- and nanofabrication. Finally, we showed that thermal excitation of SPPs in patterned metallic structures can provide tailored thermal emission. Typically, SPPs on metal structures are generated by using an optical source and then re-radiated as light, of which the emission angle and wavelength are determined by the geometry of the metal structures. However, since thermal energy can be another excitation source to create SPPs, heating of properly designed metal structures can result in tailored thermal emission. We experimentally demonstrated that at high temperatures, tungsten films with bull's-eye patterns exhibit tailored thermal emission with a unidirectional and monochromatic beam. In addition, since the thermal stability of the structures could be enhanced by coating with a protective oxide layer on the metal surface, the bull's-eye structures can be utilized as a novel radiation source. Overall, we pursued efficient engineering of SPPs in metal structures and development of improved fabrication methods for the metal structures. We believe that these results will promote the practical application of SPPs for electronic, photonic and plasmonic devices.

Many studies have shown that uridylation, a post- transcriptional modification that results in the addition of non-templated uridines to the 3' ends of various RNAs, effect the stability of these transcripts. Belonging to the same family as canonical nucleotidyl transferases such as the well characterized poly(A) polymerase, non- canonical nucleotidyl-transferases (nc-rNTrs) are template -independent polymerases capapble of catalyzing the transfer of single or multiple nucleotide residues to the 3' ends of various RNAs. Here we identified the in vitro activities of six of the seven human nc-rNTrs. We found that TUTases 4 and 7 are prefer to add uridines, while TUTases 2, 3 and 5 prefer to add adenines. Furthermore, we studied uridylation of microRNA-directed 5' cleavage products in vivo. Our preliminary results identified TUTase 2 and 7 as the enzymes that may be responsible for the uridylation of the 5' cleavage fragment. Knockdown of these enzymes in combination led to a decrease in uridylated transcripts. Here, we laid the groundwork for future experiments that will help elucidate the effects of uridylation on mRNA stability

Extensive profiling studies over the past several years have demonstrated that various miRNAs are differentially expressed in most cancers. Uncovering potential targets, and biogenesis regulation factors will be necessary for miRNA based cancer therapy in the future. We identified a novel target gene of miR-132 and miR-212 which are over-expressed in pancreatic adenocarcinoma (PDAC). Both miRNAs directly regulate the retinoblastoma tumor suppressor, Rb1, in pancreatic tumor cells. Cell proliferation was enhanced in panc-1 cells by ectopic expression of pre-miR-132/-212 oligos together with increased E2F target genes. Conversely, antisense oligos to miR-132/-212 reduced cell proliferation and caused a G2/M cell cycle arrest. Beta 2 adrenergic receptor agonist, terbutaline, increased the miR-132 and miR-212 expression in panc-1 cells. Differentially expressed miRNAs in hepatocellular carcinoma (HCC) include miR-221 (up-regulated) and miR-199a-3p (down-regulated). Therapeutic efficacy of miR-221 antisense oligonucleotides and a tumor suppressive role of miR-199a-3p were evaluated in HCC. The cholesterol-modified anti-miR-221 (chol-anti-miR-221) had improved pharmacokinetics and liver tissue distribution compared to the non-cholesterol labeled oligonucleotide. Intravenously administered chol-anti-miR-221 accumulated in the tumors of orthotopic mouse models of HCC. Anti-miR-221 was effective at inhibiting endogenous miRNA and modulating target gene expression. Chol-anti-miR-221 produced a survival advantage in orthotopic mice compared to those mice treated with a scrambled control. To determine if miR-199a-3p has a tumor suppressive role, pre-miR-199a-3p oligonucleotides were transfected into the HCC cell lines. Pre-miR-199a-3p reduced cell proliferation by approximately 60% compared to control oligonucleotide in SNU449 and SNU423 cells. Immunoblotting demonstrated that only the two HCC cell lines that were sensitive to the effects of pre-miR-199a-3p were CD44+. Direct targeting of CD44 by miR-199a-3p was confirmed in HCC cell lines. In addition, transfection of miR-199a-3p into SNU449 cells reduced in vitro invasion and sensitized the cells to doxorubicin.In conclusion, identification of target genes of miR-132/-212 and miR-199a-3p may be useful for targeted therapy of PDAC and HCC, respectively. A miR-221study demonstrated the feasibility and therapeutic efficacy of selectively targeting a miRNA that is over-expressed in HCC using antisense oligonucleotides.

Development of wavelength selective detection, tunable multi-spectral capability with functionality in the infrared spectral region is highly desirable for a variety of applications such as thermography, chemical processing and environmental monitoring, spectroradiometry, medical diagnosis, Fourier transform infrared spectroscopy, night vision, mine detection, military defense and astronomy. Infrared detector with wavelength selective functionality have emerged as next generation infrared detectors. This study presents fabrication and characterization of wavelength selective Germanium dielectric coated Salisbury screen and novel 3D stacked microbolometer for multispectral infrared detection. This novel fabrication process helps produce much flatter, more robust device structure by using an un-patterned sacrificial layer to produce device legs that hold the central structural layer above the reflective mirror supported by a completely flat sacrificial layer with sufficient thermal isolation to allow microbolometer operation. For the fabricated wavelength selective Germanium dielectric coated Salisbury screen microbolometer using self aligned process, the FTIR measured spectral responses and numerical simulation results show excellent agreement with wavelength selectivity (9[mu]m, 10[mu]m, 11[mu]m) in long wave infrared (LWIR) region. To achieve multicolor infrared detection, recently a few device concepts using uncooled detectors have been reported. However, none of the proposed device designs have demonstrated fabrication. Moreover, Commercial Fabry-perot resonant cavity based uncooled microbolometers (Air gap: 2 to 2.5μm) have limited design parameters due to multicolor narrow band spectral response. In this study, a feasible device fabrication method for novel 3D stacked microbolometer is demonstrated for multispectral uncooled infrared detector that can achieve tunable narrowband absorption in mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions.

The overall goal of this investigation was to elucidate specific structure-property relationships in perfluorosulfonate ionomers (PFSIs)-related materials. The project can be broken into two primary foci. First, we explored the current state of understanding related to morphology-property relationships in PFSIs with specific attention to the nano-scale organization of the ionic and crystalline domains. Specifically, the effect of uniaxial orientation on the structure and transport properties of Nafion® membranes was examined. Small angle X-ray scattering (SAXS) experiments on dry membranes that were uniaxially elongated showed a strong anisotropic morphology which was shown to persist over the swelling process without a significant relaxation. Herman's order parameters for the ionomer peak were strongly influenced by uniaxial deformation, which supports the presence of cylindrical rather than spherical morphology for ionic domains. Comparison of the water diffusion coefficients between unoriented and oriented samples revealed that uniaxial deformation of Nafion® membranes essentially enhances transport ability in one direction (i.e., the parallel to draw direction) and suppresses in the other two directions (i.e., two orthogonal directions relative to the stretching direction). Based on 1-dimensional analyses of oriented SAXS patterns at the azimuthal angle 90o, three recent models (lamellar model, semicrystalline rod-like model and fringed-micelle model) for the morphology of PFSIs were critically evaluated. The loss of meridional scattering, different orientation behavior of the crystalline and ionic domains, and inherent chain stiffness precludes the possibility of a chain-folded lamellar morphology. While the inter-aggregate dimensions remain constant at high draw ratios, the inter-crystalline spacings decrease significantly. Coupled with the distinctly different orientation behavior, these observations preclude the existence of crystallites solely within rod-like aggregates. While the worm-like ionic channel model was able to explain the behavior of SAXS and wide angle X-ray scattering (WAXS) relatively well, this model also had limitations such as (1) crystalline domains directly linked to the ionic domain (and thus a lack of amorphous domains) and (2) a presence of only a single ionic channel between two neighboring crystallites. Second, electroactive materials, specifically ionic polymer-metal composites (IPMCs) that undergo bending motions with the stimulus of a relatively weak electric field were fabricated. To understand the role of the nanoscale morphology of the membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated actuation performance of IPMCs subjected to uniaxial orientation. The PFSI nanostructure altered by uniaxial orientation mimicked the fibrillar structure of biological muscle tissue and yielded a new anisotropic actuation response. It was evident that IPMCs cut from films oriented perpendicular to the draw direction yielded displacement values that were significantly greater than that of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appeared to resist bending and yield displacement values that were much less than that of the unoriented IPMC. This anisotropic actuation behavior was attributed to the contribution of the nanoscale morphology to the bulk bending modulus. Overall, this study clearly demonstrated, for the first time, the importance of the nanoscale morphology in affecting/controlling the actuation behavior in IPMC systems.

Future space missions require cooling of large optical structures and cryogenic storage systems. A distributed network of cooling elements, each including actively controlled valves, can provide location specific temperature control. This thesis presents piezoelectrically actuated microvalves for modulating refrigerant flow in a cryogenic cooling system. The first-generation valve consists of a micromachined die fabricated from silicon and glass wafers, a piezoelectric stack actuator, and Macor ceramic encapsulation, having overall dimensions of 1×1×1 cm3. The silicon valve seat is suspended by a crab-leg flexure formation and attached to the piezoelectric stack actuator, which moves in an out-of-plane motion against the glass substrate. To overcome modest displacement provided by piezoelectric actuation, a perimeter augmentation scheme for the valve seat has been implemented to increase flow area and consequently provide high flow modulation. The valve can modulate the flow from 980 mL/min with the valve fully open (0 V) to 0 mL/min with 60 V actuation voltage at a pressure difference of 55 kPa at room temperature. The operation of the valve has been validated at temperatures over 80-380 K, and at pressures up to 130 kPa. The valve has a response time of less than 1 msec and has an operation bandwidth up to 820 Hz. It is used in the Joule-Thomson self-cooling test with a micromachined recuperative heat exchanger, and a temperature decrease of as much as 42 K is presented. For the second-generation design, a similar architecture is used with integrated sensors for inlet pressure and temperature. Implementation of a membrane type suspension substantially decreased the dead volume inside the valve. At room temperature, a normally-open valve achieved gas flow modulation from 200 mL/min to 0 mL/min with 0 V to 40 V actuation. Sensors are strategically positioned at the upstream end of the valve so that the information can be used for closed-loop control. Sensitivities of 356 ppm/kPa for the piezoresistive pressure sensor and 0.29 %/K for the platinum resistance temperature detector (RTD) are reported. These valves are compatible with liquids, thus the liquid modulation, using the valve for drug delivery application, is briefly discussed.

The goal of this thesis is to investigate the use of nanoparticles as a means of self-assembly into target structures and as candidates for a variety of applications such as advanced materials, nanodevices, and drug delivery systems. Materials with a well-organized distribution and an orientation provide superior properties that cannot be achieved by the current uniformly or randomly dispersed nanocomposites. An approach to rigorously calculate the driving force for core-shell nanoparticles, taking into account the thermal motion, may suggest a significant degree of the experimental control and contribute to materialization of the distinguished properties. Electrostatic interactions also demonstrate that organizing different nanoparticles systematically into ordered binary superlattices can lead to functional materials. The work elucidates how parameters including permittivity, volume fraction, particle size, and the frequency of the field can be utilized to control the morphology of the superlattice structures. The study explores a wide range of superlattices from functional gradient columns to an alternating chain-network. Poly (amidoamine) dendrimer nanoparticles have been employed extensively in biomedical applications such as drug delivery systems. They disrupt cell membranes and allow the transportation of agent materials into cells. The results of a three dimensional phase field model demonstrate that an amine-terminated G7 dendrimer, which has positive charges on the surface, causes a hole in the membrane. The molecules removed from the membrane encircle the dendrimer and form a dendrimer-filled membrane vesicle. This behavior is significantly reduced for smaller dendrimers. An acetamide-terminated dendrimer, which has a neutral charge, does not induce a hole effectively. Relatively larger particles, such as liquid droplets, also have diverse applications such as ‘lab-on-a-chip’ systems for biomedical diagnostics. A phase field model, combining the thermodynamics and hydrodynamics, predicts a dynamic motion of a droplet on designed electrodes, which is an important factor for designing devices. Furthermore, it predicts the instability occurrence at a high field strength, which is observed from experiments. A parametric study, combined with a stability analysis, shows a tendency of the instability to depend on the surface energy and the strength of the applied field.

Sometime before 1579, Zhou Lujing (1542--1633), a professional writer living in a bustling commercial town in southeastern China, published a series of lavishly illustrated books entitled Huilin and Huasou, which constituted the first multi-genre painting manuals in Chinese history. Their popularity was immediate and their contents and format were widely reprinted and disseminated in a number of contemporary painting manuals. As a special commodity of early modern China, when people's cultural standing was measured by their command of literati taste and lore, Huilin and other painting manuals provided a growing reading public with a device (or simply the illusion of such) for enhancing social capital. Focusing on Zhou's painting manuals, this dissertation will describe how such publications accommodated the cultural taste and demands of the general public; in other words, I will point to how painting manuals functioned as a form in which everything from icons of popular culture to graphic or literary cliche was presented to both gratify and shape the sensibilities of a growing reading public. The manuals accomplish this in three ways: through the selection of visual motifs, the manipulation of pictorial styles, and through written guides to artistic choice. As a result, many features of Huilin and other painting manuals do not correspond to late Ming artistic practice and knowledge as described by contemporary critics and accounts of the lives of major artists. Staking out the cultural high ground, leading critics and master painters of the time criticized these manuals as suitable only to philistine tastes. They even claimed that the program registered in these manuals was harmful to true artists who aspired to innovation and authenticity in their painting. They promoted instead a new cultural paradigm emphasizing originality in art and literature, which, I argue, was triggered by the very popularity of painting manuals among late Ming public. Such disjunctures in artistic taste underscore how the production and consumption of painting manuals intertwined with the taste-making mechanisms that affected both low- and high-brow consumers in early modern China.

The development of fully automated machine tools requires reliable tool monitoring methods; particularly reliable on-line tool wear measuring methods. Among the two major types of tool wear (i.e., flank wear and crater wear) the amount of flank wear is more often used in determining the tool life, and the mechanism of its development is better understood. In this study, the problem of developing a reliable on-line flank wear measuring method is treated using adaptive observer techniques based on cutting force measurement and computer vision. In a previously developed flank wear model, the flank wear is represented as the summation of two unmeasureable states in a nonlinear dynamic system realized in state space equation form. The inputs to the system are the feed, the cutting speed and the depth of cut, i.e., the cutting condition, and the output is the cutting force. Based on this model, a nonlinear observer is designed using the fact that flank wear development is physically bounded. The flank wear is estimated on-line using this nonlinear observer and the measurements of the cutting force and the cutting conditions. However, for the use of the nonlinear observer in practice, extensive preliminary experiments are required to determine the model parameters. To eliminate the need for such experiments, two types of adaptive observers are designed, based on a simplified flank wear model and the Recursive Prediction Error parameter estimation method. These adaptive observers simultaneously estimate the flank wear and a unknown flank wear model parameter, using the measurements of the cutting force and the cutting conditions. One of the adaptive observers is integrated with a computer vision system developed for direct measurement of the flank wear. In the integrated system, the adaptive observer is intermittently calibrated using direct flank wear measurements via the computer vision. This method is particularly effective in cutting operations where several computer vision measurements are available throughout the tool life. This integrated method has been evaluated through cutting experiments under constant cutting conditions and time varying cutting conditions in which the feed was repeatedly changed stepwise, and yielded excellent results for on-line flank wear estimation.

The numerical stability of nonlinear body-wave interaction problems is investigated by applying potential flow assumptions to oscillating, non-wallsided two-dimensional and three-dimensional axisymmetric bodies. This body-wave interaction problem is solved using a mixed two-step Eulerian-Lagrangian method. In the first step, Laplace's equation is solved to determine the unknown potential values on the body and the unknown derivatives of the potentials on the free surface. In the second step, free surface boundary conditions are applied using the results of the first step to find the evolved free surface location and new potential values on the new location. Each step has particular mathematical characteristics (elliptic or parabolic-like), so that each step requires different numerical schemes. Consequently, the numerical stability of this body-wave interaction problem contains the characteristics of both of these two steps. The major contributions made to this body-wave interaction problem are the effects of the various parameters (i.e. time increments, panel length, etc.) and the different forms of the Boundary Integral Method (BIM) on numerical stability and accuracy. The far-field truncation requirement is met by matching the linear outer solution to the nonlinear inner solution at the truncation boundary. The intersection point is traced by the extrapolation method with a special boundary condition at the intersection point. To determine the evolution of the free surface according to a Lagrangian model, a regridding scheme is utilized to prevent the concentration of the Lagrangian markers in the vicinity of high gradients. A parameter for the numerical stability of free surface waves, the Free Surface Stability (FSS) number, is defined as a function of the time step size and the discretized panel length. The various stability regions are investigated by changing the FSS number, Green's function constant c, and numerical schemes. A nonlinear stability analysis is also compared to the results of the linear stability analysis for a number of specific conditions to study the effect of nonlinear boundary conditions.

The collective processing of multiple transactions in a database system has recently received renewed attention due to its capability of improving the overall performance of a database system and its applicability to the design of knowledge-based expert systems and extensible database systems. This dissertation consists of two parts. The first part presents a new knowledge-based approach to the problems of processing multiple concurrent queries and distributing replicated data objects for further improvement of the overall system performance. The second part deals with distributed database design, i.e., designing horizontal fragments using a semantic knowledge, and allocating data in a distributed environment. The semantic knowledge on data such as functional dependencies and semantic data integrity constraints are newly exploited for the identification of subset relationships between intermediate results of query executions involving joins, such that the (intermediate) results of queries can be utilized for the efficient processing of other queries. The concept of the conventional query graph is extended to represent distributed transaction executions by the inclusion of site information. A state of the problem space is represented by this extended query graph. The expertise on the collective processing of multiple transactions is embodied into the rules of a rule-based expert system, MTP (Multiple Transaction Processor). These expert rules exploit large amounts of domain-specific semantic knowledge to reformulate the execution plans of queries such that the overall processing cost is substantially reduced. MTP employs the planning technique combined with search method where the plan step infers the necessary constraints, and the search step achieves optimal solutions utilizing the ${\\rm A\\sp\\ast}$ or branch and bound search technique. In the second part, MTP is applied for the determination of horizontal fragments exploiting the semantic knowledge. Heuristics for allocating data in local area networks are developed. In summary, this knowledge-based approach adds to knowledge for the processing of multiple transactions in a distributed environment, and to the design of knowledge-based expert systems which require efficient access to a large knowledge-base implemented on (distributed) relational database systems.