Alignment Theory of Parallel-beam CT Image Reconstruction for Elastic-type Objects using Virtual Focusing Method

X-ray tomography has been studied in various fields. Although a great deal of effort has been directed at reconstructing the projection image set from a rigid-type specimen, little attention has been addressed to the reconstruction of projected images from an object showing elastic motion. Here, we present a mathematical solution to reconstruct the projection image set obtained from an object with specific elastic motions: periodically, regularly, and elliptically expanded or contracted specimens. To reconstruct the projection image set from expanded or contracted specimens, we introduce new methods; detection of sample's motion modes, mathematical re-scaling pixel values and converting projection angle for a common layerComment: 30 pages, 11 figure

The effects of periodic and non-periodic inputs on the dynamics of a medial entorhinal cortex layer II stellate cell model

Various neuron types exhibit sub-threshold and firing frequency resonance in which the sub-threshold membrane potential or firing frequency responses to periodic inputs peak at a preferred frequency (or frequencies). Previous experimental work has shown that medial entorhinal cortex layer II stellate cells (SCs) exhibit sub-threshold and firing frequency resonance in the theta frequency band (4 - 10 Hz). In this thesis we seek to understand the biophysical and dynamic mechanism underlying these phenomena and how they are related. We studied the effects of sinusoidal current and synaptic conductance inputs at various frequencies, with and without noise, on the supra-threshold dynamics of a SC model. For current inputs, our results show that while the SC model exhibits a single frequency preference peak (in the theta frequency band) for low sinusoidal input levels, it exhibits three preferred frequency peaks for larger input levels. These additional peaks occur at frequencies that are roughly a multiple of the theta one. For synaptic conductance inputs, we observe an additional peak in the signal gain which occurs at a much higher frequency (in the high gamma frequency band). These findings depart from the linear prediction. The corresponding linearized model does not exhibit three preferred frequency peaks for current inputs and a much higher frequency for conductance inputs under the same conditions (such as parameters, noise, amplitude of inputs and maximal synaptic conductance) in the nonlinear model. Previous experimental work has shown high-frequency Poisson-distributed trains of combined excitatory and inhibitory conductance- and current-based synaptic inputs reduce amplitude of subthreshold oscillations of SCs. The second goal of this thesis is to investigate the mechanism underlying these phenomena in the context of the model. More specially, we studied the effects of both conductance- and current-based synaptic inputs at various maximal conductance values on a SC model. Our numerical simulations show that conductance-based synaptic inputs reduce the amplitude of SC\u27s subthreshold oscillations for low enough value of the maximal synaptic conductance value but amplify these oscillations at a higher range. These results are in contrast to the experimental results

Band Topology and Linking Structure of Nodal Line Semimetals with Z2 Monopole Charges

We study the band topology and the associated linking structure of topological semimetals with nodal lines carrying $Z_{2}$ monopole charges, which can be realized in three-dimensional systems invariant under the combination of inversion $P$ and time reversal $T$ when spin-orbit coupling is negligible. In contrast to the well-known $PT$-symmetric nodal lines protected only by $\pi$ Berry phase in which a single nodal line can exist, the nodal lines with $Z_{2}$ monopole charges should always exist in pairs. We show that a pair of nodal lines with $Z_{2}$ monopole charges is created by a {\it double band inversion} (DBI) process, and that the resulting nodal lines are always {\it linked by another nodal line} formed between the two topmost occupied bands. It is shown that both the linking structure and the $Z_{2}$ monopole charge are the manifestation of the nontrivial band topology characterized by the {\it second Stiefel-Whitney class}, which can be read off from the Wilson loop spectrum. We show that the second Stiefel-Whitney class can serve as a well-defined topological invariant of a $PT$-invariant two-dimensional (2D) insulator in the absence of Berry phase. Based on this, we propose that pair creation and annihilation of nodal lines with $Z_{2}$ monopole charges can mediate a topological phase transition between a normal insulator and a three-dimensional weak Stiefel-Whitney insulator (3D weak SWI). Moreover, using first-principles calculations, we predict ABC-stacked graphdiyne as a nodal line semimetal (NLSM) with $Z_{2}$ monopole charges having the linking structure. Finally, we develop a formula for computing the second Stiefel-Whitney class based on parity eigenvalues at inversion invariant momenta, which is used to prove the quantized bulk magnetoelectric response of NLSMs with $Z_2$ monopole charges under a $T$-breaking perturbation.Comment: 4+28 pages, 3+17 figure

focusing on the fear of missing out (FOMO) effect

Thesis(Master) -- KDI School: Master of Public Policy, 2021The main objective of this study is to empirically investigate the existence of the herding phenomena in the cryptocurrency market, and if so, explore whether the Fear of Missing Out affect such phenomena. To that end, the data utilized are the cryptocurrency price data, the Economic Policy Index (EPU Index) of the United States, and the Fear and Greed Index (FGI). Thirty-seven cryptocurrencies daily price data cover from January 1st, 2014, to August 31st, 2021. The EPU Index indicates the degree of an uncertain economic policy environment that the investors face. Whereas the FGI is the proxy for the Fear of Missing Out phenomenon in the market. The core methodology is Cross-Sectional Absolute Deviation (CSAD). Based on the structural break detected in the market trend, a 60-days rolling window CSAD regression is applied. The main findings are as follow. First, eight separate periods of herding are observed in the total sample period. Second, uncertain sentiment on economic policy increased the probability of herding occurrence. Third, a higher level of greed that prevails in the cryptocurrency market also increases the likelihood of herding. Fourth, the herding phenomenon did not mean a significantly different level of return on investment, compared to the return under the non-herding period.1. Introduction 2. Background 3. Data and Methodology 4. Empirical Results 5. Conclusion and Policy SuggestionsOutstandingmasterpublishedDongwook KI

温度応答性を有する全イオン性PIC (ポリイオンコンプレックス)ミセルの基礎物性

京都大学新制・課程博士博士(工学)甲第23222号工博第4866号新制||工||1759(附属図書館)京都大学大学院工学研究科高分子化学専攻(主査)教授 秋吉 一成, 教授 大内 誠, 准教授 松岡 秀樹学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Local House Price Indexes: 1982-1991

We begin with a description of three house price panel data sets for the period 1982 to 1991. Next, we estimate a model that assumes the three sources are derived from an underlying unobserved price series, and we construct composite indexes that report house prices for 135 locations. These series can be used either as explanatory variables in studies of household formation, housing demand, and migration or to test models of the determinants of spatial and intertemporal variations in house prices. Finally, we construct regional series (based, alternatively, on census and Salomon Brothers regions) and two national aggregates and describe their movements. Our series are compared to other local, regional, and national series.

Change of the yield stress in roll formed ERW pipes considering the Bauschinger effect

ERW pipes formed with the roll forming process show a yield stress distribution along the circumferential direction and their quality is strongly influenced by the magnitude and by the distributions of the yield stress. In addition to that, strips are subjected to cyclic loading during roll forming process. Since ERW pipes are firstly roll formed, welded and then sized, in order to develop an enhanced predicting method for the calculation of the ERW pipe yield stress, the same process flow has been also applied to authors\u2019 numerical simulations. The Yoshida-Uemori kinematic hardening model has been applied considering several subdivision of the strain range, and different parameters, aiming to find the best correlation between the estimated Bauschinger effect and the one measured in the relevant cyclic loading experiment. The comparisons between estimated and experimentally-measured values of the thickness distribution, and of the locally-measured yield stress, prove both reliability and accuracy of the adopted process chain analysis. The growth of the sizing effect ratio has shown to cause the increase of the yield stress, which becomes more uniform along the circumferential direction