• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.171-179
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• 2001

The purpose of this paper is the derivation and development of the new definitions and methods for the new estimation of robustness for the systems having structured uncertainties. This proposition adopts the theoretical analysis of the Lyapunov direct methods, that is, the sign properties of the Lyapunov function derivative integrated along finite intervals of time, in place of the original method of the sign properties of the time derivative of the Lyapunov function itself. This is the new sufficient criteria to relax the stability condition and is used to generate techniques for the robust design of control systems with structured perturbations. The systems considered are assumed to be nominally linear, with time-variant, nonlinear bounded perturbations. This new techniques demonstrate the improvement of robustness bounds from the numerical results.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1209-1212
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• 1999

The entropies and chemical potentials of hard-sphere solutes solvated in hard-sphere solids were calculated by Monte Carlo method using the radial free-space distribution function. This method is based on calculating the entropy by comparing the free volume of a molecule with that of an ideal gas, and is applicable even when the size of solute is very large and the solvent is a solid. When the diameter of hard-sphere solute is small the solute molecule behaves as like as a fluid in solid structures, but when the diameter of solute becomes large, a fluid-to-solid phase transition takes place. The fluid-to-solid phase transition occurs at the region of the smaller size of solute with the more increase of solvent density. The least square fit values of analytical form of the radial free-space distribution functions of solute molecules are presented for future uses.

• Nuclear Engineering and Technology
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• v.36 no.5
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• pp.430-449
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• 2004

A quantitative model for a control system that integrates human operators, systems, and their interactions is developed based on discrete functions. After identifying the major entities and the key factors that are important to each entity in the control system, a quantitative analysis to estimate the recovery failure probability from an abnormal state is performed. A numerical analysis based on assumed values of related variables shows that this model produces reasonable results. The concept of 'relative sensitivity' is introduced to identify the major factors affecting the reliability of the control system. The analysis shows that the hardware factor and the design factor of the instrumentation system have the highest relative sensitivities in this model. T도 probability of human operators performing incorrect actions, along with factors related to human operators, are also found to have high relative sensitivities. This model is applied to an analysis of the TMI-2 nuclear power plant accident and systematically explains how the accident took place.

• Journal of Plant Biology
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• v.25 no.2
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• pp.73-81
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• 1982

The changes in activities of glyoxysomal and peroxisomal enzymes during the transition from fat degradation to photosynthesis were investigated with the cotyledns of rape (Brassica napus L.) seedlings. The development and disappearance of glyoxysomal enzyme (isocitrate lyase, EC 4.1.3.1; malate dehydrogenase, EC 1.1.1.37; catalase, EC 1.11.1.6) activities took place independently of light. It is concluded that the mobilization of storage fat is independent of photomorphogenesis. During early periods of development in the dark of light (days 1 through 3), the glyoxysomal enzyme activities were relatively high and the enzyme activities rose to a peak at 3rd day after sowing. Thereafter, the activities decreased gradually. While glyoxysomal enzyme activities were dropping, the peroxisomal enzyme (glycolate oxidase, EC 1.1.3.1) activities were increasing rapidly during the transition period in the light. Moreover, the changes of enzyme activities of the common microbody marker, catalase, indicated both functional patterns. The enzyme patterns in rape cotyledons indicate that the glyoxysomal function of microbodies is replaced by the peroxisomal function of these organelles during the transition from fat degradation to photosynthesis.

• Journal of Information Technology Services
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• v.18 no.1
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• pp.131-140
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• 2019

This study compares and analyzes the spatial distribution of people in two cities using location information in twitter data. The target cities were selected as Paris, a traditional tourist city, and Dubai, a tourist city that has recently attracted attention. The data was collected over 123 days in 2016 and 125 days in 2018. We compared the spatial distribution of two cities according to the two periods and residence status. In this study, we have found a hot place using a spatial statistical model called dart-shaped space division and estimated the urban area by reflecting the distribution of tweet population. And we visualized it as a CDF (cumulative distribution function) curve so that the distance between all the tweets' occurrence points and the city center point can be compared for different cities.

• Journal of architectural history
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• v.31 no.2
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• pp.51-65
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• 2022

Seoju is one of the nine weeks of the ancient period, and according to literature records, the construction of Seojuseong Fortress has a long history of 2573. This is the land of Oseongtong-gu, a political and military hub, and flood disasters have frequently led to frequent reconstruction of fortresses. In particular, it is also an important place to show that the function of the fortress is defensive and has a function of preventing floods. This study analyzed the shape of Seojuseong Fortress and the characteristics of urban spaces in the Myeongcheong period through excavation data and literature data.

• Journal of the Korean Regional Science Association
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• v.31 no.1
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• pp.3-20
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• 2015

The objective of this study is to identify the applicability of urban network theory. The degree of network and city size of 163 Si-Guns in Korea are used to perform an empirical analysis for 2005 and 2010. The result indicates that the effect of city size (based on central place theory) is still larger than the network effect (based on urban network theory). However, the effects are different according to the industrial types. The size-based effectis more efficient in manufacturing sector, whereas the network-based effect is more efficient in service industry. The trend from 2005 to 2010 indicates that there is an increasing pattern in network-based effect and decreasing patternin size-based effect. It is necessary to recognize continual benefit of the sized-based effect, however it is also important to distinguish different characteristics of the functional form by the size and network. The feasibility of the urban network theory is tested in this study with the empirical analysis and recommends the importance of policy implication with recognition of the distinction between size and network-based effects.

• BMB Reports
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• v.40 no.4
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• pp.475-485
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• 2007

Methamphetamine is an illicit drug that is often abused and can cause neuropsychiatric and neurotoxic damage. Repeated administration of psychostimulants such as methamphetamine induces a behavioral sensitization. According to a previous study, Bax was involved in neurotoxicity by methamphetamine, but the function of Bax in rewarding effect has not yet been elucidated. Therefore, we have studied the function of Bax in a rewarding effect model. In the present study, we treated chronic methamphetamine exposure in a Bax-deficient mouse model and examined behavioral change using a conditioned place preference (CPP) test. The CPP score in Bax knockout mice was decreased compared to that of wild-type mice. Therefore, we screened for Bax-related genes that are involved in rewarding effect using microarray technology. In order to confirm microarray data, we applied the RT-PCR method to observe relative changes of Bcl2, a pro-apoptotic family gene. As a result, using our experiment microarray, we selected genes that were associated with Bax in microarray data, and eventually selected the Tgfbr2 gene. Expression of the Tgfbr2 gene was decreased by methamphetamine in Bax knockout mice, and the gene was overexpressed in Bax wild-type mice. Additionally, we confirmed that Creb, FosB, and c-Fos were related to rewarding effect and Bax using immunohistochemistry.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.169-180
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• 2016

The spaces of port and urban in a Port City have different space characteristics substantially, but those are required to be developed interdependently. Degradation and loss of the sense of place in the existing spaces caused by decline of natural function have an adverse effect on the revival of local economy as well as make worse image of the entire city. In some developed countries, therefore, many researches on the port spaces lagging behind the times due to changes of the characteristics and function of port spaces have been conducted continuously for a long time. This study aims at seeking a device how the domestic hinterland could be utilized as efficient spaces having the characteristics of outskirts space and port city interface through the application of characteristics of the interface space of port city, capable of playing a role as buffer zone between the port space and the city space.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.264-267
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• 2009

Today, our lifestyle and residential culture has been changed have been changed by interchange with various countries in various sides. In order to become an internationally recognized residential environment designer in this environment, we must understand the housing viewpoint of residents in a country first. Therefore, this study was intended to obtain useful material for residential environment design of both countries by comparing the housing viewpoint between Chinese students studying in Korea and Korean students. A questionnaire was conducted on 205 Korean students and 193 Chinese students (Korean race) from Y University in random sampling basis. The result is as follows. First, both Korea and China have a higher ratio of apartments in both current and previous types of house. But, both Korea and China have similar ratios between detached house and apartment for a desired type of house at the time of moving in. Second, Korean and Chinese university students consider and as the most important functions of residence, and Chinese university students consider more functions of residence than Korean students. Third, both Korean and Chinese consider a living room as the most important space among housing spaces, but Chinese consider a private room more importantly than Korean. Fourth, overall satisfaction rate of Korean students for current houses was average, and most Chinese students were generally satisfied with their houses.