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京都大学 / 新制・課程博士 / 博士(情報学) / 甲第24038号 / 情博第794号 / 新制||情||134(附属図書館) / 京都大学大学院情報学研究科数理工学専攻 / (主査)准教授 辻本 諭, 教授 梅野 健, 教授 矢ヶ崎 一幸 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Investigation of simply supported Multilayer sandwich beams with symmetrical loading and of Multipier shear walls with arbitrary horizontal loadings. The analysis contains the influence of normal deformation of the layers and piersrespectively. / Thesis / Master of Engineering (ME)

Bakgrund: Normaltryckshydrocefalus (NPH) är ett neurologiskt tillstånd som innefattar psykiska funktionsnedsättningar, demenssymtom, inkontinens samt problem med gång. Behandlingen för detta är via shuntoperation. Gångförmågan undersöks via gångtester innan och efter ett tapptest, som sedan ligger till grund för att diagnos ska kunna ställas.   Syfte: Syftet med arbetet var att undersöka gångförmågan hos patienter med NPH genom att jämföra gångtesters resultat mätt i sekunder innan tapptest och shuntoperation med resultat efter shuntoperation, samt jämföra skillnader mellan män och kvinnor.    Metod: För studien valdes en kvantitativ metod med en deskriptiv komparativ design. Data som bearbetats i den aktuella studien kommer från ett pågående forskningsprojekt på ett universitetssjukhus där det samlats in resultat av tre gångtester innan shuntoperation och tre månader efter. Totalt var det 161 patienter med NPH i forskningsstudien varav 129 inkluderades i den aktuella studien. Av dessa var 65 stycken män och 64 stycken kvinnor. Gångtesterna som jämförs är Timed up and go (TUG), 10 meter walk test (10 MWT) och 3 meter backwards walk (3 MBW).   Resultat: Resultatet visade på en signifikant förbättring i alla gångtester tre månader efter shuntoperation jämfört med innan operation, samt att det inte förelåg någon signifikant skillnad mellan män och kvinnor. TUG förbättrades med 5 sekunder, 10 MWT förbättrades med 4 sekunder samt att 3 MBW förbättrades med 4 sekunder.   Konklusion: Resultaten visar på att det sker en signifikant förbättring i gångtester för patienter med NPH som genomgått en shuntoperation. Vidare forskning krävs för att säkerställa att gångtesterna är relevanta för personer med NPH, samt för att uppnå ett standardiserat testbatteri som går att applicera över hela populationen. / Background: Normal pressure hydrocephalus (NPH) is a neurological condition that causes cognitive symptoms, dementia, incontinence and difficulties with walking. The treatment for this is shunt surgery. The ability to walk is examined with walking tests before and after a tap test, which then forms the basis for a diagnosis.   Purpose: The purpose of the study was to examine patients with NPH ability to walk through comparison of the results of walking tests measured in seconds before lumbar puncture test and shunt surgery with the results three months after shunt surgery, as well as comparing differences between men and women.   Method: A quantitative method with a descriptive and comparative design was chosen for this study. Data in the current study comes from an ongoing research project at a university hospital that has c ollected data of results of three walking tests before and three months after shunt surgery. In total data from 161 patients with NPH was collected of which 129 patients was included in the current study. Of these were 65 men and 64 women. The walking tests compared are Timed up and go (TUG), 10 meter walk test (10MWT) and 3 meter backwards walk (3MBW)  Results: The results showed a significant improvement in all walking tests before compared to three months after shunt surgery and that there was no significant difference between men and women. The results of TUG improved by 5 seconds, 10MWT by 4 seconds and 3MBW by 4 seconds.  Conclusion: The results show that there is a significant improvement in walking tests for patients with NPH who have undergone shunt surgery. Further research is required to ensure that the walking tests are relevant for people with NPH, as well as to achieve a standardized test battery that can be applied to the entire population.

The rapid growth in demand for cellular mobile communications and emerging fixed wireless access has created the need to increase system capacity through more efficient utilization of the frequency spectrum, and the need for better grade of service. In cellular systems, capacity improvement can be achieved by reducing co-channel interference. Several techniques have been proposed in literature for mitigating co-channel interference, such as adaptive antennas and power control. Also, by allocating transmitter power and communication channels efficiently (resource allocation), overall co-channel interference can be maintained below a desired maximum tolerable level, while maximizing the carried traffic of the system. This dissertation presents investigation results on the performance of base station adaptive antennas, power control and channel allocation, as techniques for capacity improvement. Several approaches are analyzed. Firstly, we study the combined use of adaptive antennas and fractional loading factor, in order to estimate the potential capacity improvement achieved by adaptive antennas. Next, an extensive simulation analysis of a cellular network is carried out aiming to investigate the complex interrelationship between power control, channel allocation and adaptive antennas. In the first part of this simulation analysis, the combined use of adaptive antennas, power control and reduced cluster size is analyzed in a cellular system using fixed channel allocation. In the second part, we analyze the benefits of combining adaptive antennas, dynamic channel allocation and power control. Two representative channel allocation algorithms are considered and analyzed regarding how efficiently they transform reduced co-channel interference into higher carried traffic. Finally, the spatial filtering capability of adaptive antennas is used to allow several users to share the same channel within the same cell. Several allocation algorithms combined with power control are analyzed. / Ph. D.

We study the behavior of numerical stabilization schemes in the context of linear quadratic regulator (LQR) control problems for convection diffusion equations. The motivation for this effort comes from the observation that when linearization is applied to fluid flow control problems the resulting equations have the form of a convection diffusion equation. This effort is focused on the specific problem of computing the feedback functional gains that are the kernels of the feedback operators defined by solutions of operator Riccati equations. We develop a stabilization scheme based on the Galerkin Least Squares (GLS) method and compare this scheme to the standard Galerkin finite element method. We use cubic B-splines in order to keep the higher order terms that occur in GLS formulation. We conduct a careful numerical investigation into the convergence and accuracy of the functional gains computed using stabilization. We also conduct numerical studies of the role that the stabilization parameter plays in this convergence. Overall, we discovered that stabilization produces much better approximations to the functional gains on coarse meshes than the unstabilized method and that adjustments in the stabilization parameter greatly effects the accuracy and convergence rates. We discovered that the optimal stabilization parameter for simulation and steady state analysis is not necessarily optimal for solving the Riccati equation that defines the functional gains. Finally, we suggest that the stabilized GLS method might provide good initial values for iterative schemes on coarse meshes. / Ph. D.

We desire an algorithm to classify a physical object in ``real-time" using an easily portable probing device. The probe excites a given object at frequencies from 100 MHz up to 800 MHz at intervals of 0.5 MHz. Thus the data used for classification is the 1400-component vector of these frequency responses. The Interdisciplinary Center for Applied Mathematics (ICAM) was asked to help develop an algorithm and executable computer code for the probing device to use in its classification analysis. Due to these and other requirements, all work had to be done in Matlab. Hence a significant portion of the effort was spent in writing and testing applicable Matlab code which incorporated the various statistical techniques implemented. We offer three approaches to classification: maximum log-likelihood estimates, correlation coefficients, and confidence bands. Related work included considering ways to recover and exploit certain symmetry characteristics of the objects (using the response data). Present investigations are not entirely conclusive, but the correlation coefficient classifier seems to produce reasonable and consistent results. All three methods currently require the evaluation of the full 1400-component vector. It has been suggested that unknown portions of the vectors may include extraneous and misleading information, or information common to all classes. Identifying and removing the respective components may be beneficial to classification regardless of method. Another advantage of dimension reduction should be a strengthening of mean and covariance estimates. / Master of Science

Harmonic oscillatory tests for a fighter aircraft using the Dynamic Plunge--Pitch--Roll model mount at Virginia Tech Stability Wind Tunnel are described. Corresponding data reduction methods are developed on the basis of multirate digital signal processing. Since the model is sting mounted, the frequencies associated with sting vibration are included in balance readings thus a linear filter must be used to extract out the aerodynamic responses. To achieve this, a Finite Impulse Response (FIR) is designed using the Remez exchange algorithm. Based on the reduced data, a state–space model is developed to describe the unsteady aerodynamic characteristics of the aircraft during roll oscillations. For this model, we chose to separate the aircraft into panels and model the local forces and moments. Included in this technique is the introduction of a new state variable, a separation state variable which characterizes the separation for each panel. This new variable is governed by a first order differential equation. Taylor series expansions in terms of the input variables were performed to obtain the aerodynamic coefficients of the model. These derivatives, a form of the stability derivative approach, are not constant but rather quadratic functions of the new state variable. Finally, the concept of the model was expanded to allow for the addition of longitudinal motions. Thus, pitching moments will be identified at the same time as rolling moments. The results show that the goal of modeling coupled longitudinal and lateral–directional characteristics at the same time using the same inputs is feasible. / Master of Science

The primary purpose of this research is to investigate the effectiveness of a scaled roller rig for accurately assessing the contact mechanics and dynamics between a profiled steel wheel and rail, as is commonly used in rail vehicles. The established creep models of Kalker and Johnson and Vermeulen are used to establish correction factors, scaling factors, and transformation factors that allow us to relate the results from a scaled rig to those of a tangent track. �Correction factors, which are defined as the ratios of a given quantity (such as creep coefficient) between a roller rig and a track, are derived and used to relate the results between a full-size rig and a full-size track. Scaling factors are derived to relate the same quantities between roller rigs of different scales. Finally, transformation factors are derived by combining scaling factors with correction factors in order to relate the results from a scaled roller rig to a full-size tangent track. Close-end formulae for creep force correction, scaling, and transformation factors are provided in the thesis, along with their full derivation and an explanation of their limitations; these formulae can be used to calculate the correction factors for any wheel-rail geometry and scaling. For Kalker's theory, it is shown that the correction factor for creep coefficients is strictly a function of wheel and rail geometry, primarily the wheel and roller diameter ratio. For Johnson and Vermeulen's theory, the effects of creepage, scale, and load on the creep force correction factor are demonstrated. �It is shown that INRETS' scaling strategy causes the normalized creep curve to be identical for both a full-size and a scaled roller rig. �It is also shown that the creep force correction factors for Johnson and Vermeulen's model increase linearly with creepage, starting with the values predicted by Kalker's theory. �Therefore, Kalker's theory provides a conservative estimate for creep force correction factors. �A case study is presented to demonstrate the creep curves, as well as the correction and transformation factors, for a typical wheel-rail configuration. �Additionally, two studies by other authors that calculate the correction factor for Kalker's creep coefficients for specific wheel-rail geometries are reviewed and show full agreement with the results that are predicted by the formulae derived in this study. �Based on a review of existing and past roller rigs, as well as the findings of this thesis, a number of recommendations are given for the design of a roller rig for the purpose of assessing the wheel-rail contact mechanics. �A scaling strategy (INRETS') is suggested, and equations for power consumption of a roller rig are derived. Recommendations for sensors and actuators necessary for such a rig are also given. Special attention is given to the resolution and accuracy of velocity sensors, which are required to properly measure and plot the creep curves. / Master of Science