• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.352-362
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• 2014

In this paper, a fuzzy logic controller is designed for a DC motor which can be used for navigation control of mobile robots. These mobile robots can be used for agricultural, defense and assorted social applications. The robots used in these fields can reduce manpower, save human life and can be operated using remote control from a distant place. The developed fuzzy logic controller is used to control navigation speed and steering angle according to the desired reference position. Differential drive is used to control the steering angle and the speed of the robot. Two DC motors are connected with the rear wheels of the robot. They are controlled by a fuzzy logic controller to offer accurate steering angle and the driving speed of the robot. Its location is monitored using GPS (Global Positioning System) on a real time basis. IR sensors in the robot detect obstacles around the robot. The designed fuzzy logic controller has been implemented in a robot, which depicts that the robot could avoid obstacle as well as perform its operation efficiently with remote online control.

• 한국의류학회지
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• 제32권7호
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• pp.1160-1168
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• 2008

The purpose of the study was to examine the effect of motif categories and motif colors on evaluating impressions of dress wearers. The research was conducted on a quasi experimental basis, with subjects numbering 187 male and 207 female college students. Data were collected in the period from march 19th to march 31st, 2007. A set of stimuli of dress wearers and semantic differential scales were developed. The stimuli were thirteen photographs editing by Youngwoo CAD system. Variables included; (a) motif colour(red, blue, achromatic and white) (b) motif categories(flower, paisley, stripes, zebra effect and plain). The semantic differential scale to measure impressions of dress wearer stimuli included 22 sets of hi-polar adjectives. The data were analysed by factor analysis and ANOVA and the major finding were as follows. Four factors emerged to account for dimension of impression. There were salience, attractiveness, comfort and femininity. The motif category effected on the four impression dimensions while the motif color effected on salience, comfort and softness sensory dimensions, and the results supported the gestalt theory of the impression perception.

• 농촌계획
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• 제17권2호
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• pp.33-41
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• 2011

To evaluate the value of a preserved tree as rural landscape resource, the growth environment and health condition was investigated, and the image evaluation was implemented on land~ape architectural major undergraduate students for zelkova trees in Yesan-gun. The image evaluation results of zelkova trees were as followings; 1) Typical image of preserved tree examined by Semantic Differential Scale were 'Old', 'Big', and 'Good'. 2) The 'big' image of zelkova tree and the height of tree, the width of tree crown, the breast girth of tree, the root girth of tree, the external formation of tree, and the health of tree bark is mutually related. Especially, the correlation between the 'big' and the external formation and the width of tree crown is high. 3) Typical image of preserved tree examined by Likert Scale were 'Natural', 'Green', 'Peaceful', and 'Rural'. 4) The preservation necessity for preserved tree was highly related with the state of ground, and the management necessity for preserved tree was highly related with contamination level and the state of ground. The appropriate management plan for preserved tree are proposed to improve the quality of rural landscape(basis of these results).

• 감성과학
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• 제6권4호
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• pp.33-40
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• 2003

본 연구는 웹 페이지 디자인의 감성모형을 구축하기 위해 실시되었다. 감성요소를 추출하기 위하여 첫째, 감성을 표현하는 어휘를 수집하고, 둘째, 감성어휘를 의미미분법을 사용해서 분류하고 셋째, 요인분석과 다차원척도법의 통계분석을 사용하였다. 본 연구결과로 얻어진 18개의 대표 어휘는 '독특하다. 신선하다, 화려하다. 소프트하다. 차갑다, 따뜻하다. 생생하다, 간단하다, 간결하다, 이색적이다, 도회적이다, 환하다, 칙칙하다, 밝다, 어둡다. 동적이다, 남성적이다, 딱딱하다'였으며, 세 개의 '밝다-어둡다', '소프트하다-딱딱하다', '간단하다-화려하다'의 감성 공간을 얻을 수 있었다.

• 한국도로학회논문집
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• 제17권5호
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• pp.1-10
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• 2015

PURPOSES : A finite difference model considering snow melting process on porous asphalt pavement was derived on the basis of heat transfer and mass transfer theories. The derived model can be applied to predict the region where black-ice develops, as well as to predict temperature profile of pavement systems where a de-icing system is installed. In addition, the model can be used to determined the minimum energy required to melt the ice formed on the pavement. METHODS : The snow on the porous asphalt pavement, whose porosity must be considered in thermal analysis, is divided into several layers such as dry snow layer, saturated snow layer, water+pavement surface, pavement surface, and sublayer. The mass balance and heat balance equations are derived to describe conductive, convective, radiative, and latent transfer of heat and mass in each layer. The finite differential method is used to implement the derived equations, boundary conditions, and the testing method to determine the thermal properties are suggested for each layer. RESULTS: The finite differential equations that describe the icing and deicing on pavements are derived, and we have presented them in our work. The framework to develop a temperature-forecasting model is successfully created. CONCLUSIONS : We conclude by successfully creating framework for the finite difference model based on the heat and mass transfer theories. To complete implementation, laboratory tests required to be performed.

• Molecular & Cellular Toxicology
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• 제4권4호
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• pp.267-277
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• 2008

Benzene and ethylbenzene (BE), the volatile organic compounds (VOCs) are common constituents of cleaning and degreasing agents, paints, pesticides, personal care products, gasoline and solvents. VOCs are evaporated at room temperature and most of them exhibit acute and chronic toxicity to human. Chronic exposure of benzene is responsible for myeloid leukemia and also ethylbenzene is also recognized as a possible carcinogen. To evaluate the BE effect on human, whole human genome 35 K oligonucleotide microarray were screened for the identification of the differential expression profiling. We identified 280 up-regulated and 201 down-regulated genes changed by more than 1.5 fold by BE exposure. Functional analysis was carried out by using DAVID bioinformatics software. Clustering of these differentially expressed genes were associated with immune response, cytokine-cytokine receptor interaction, toll-like signaling pathway, small cell lung cancer, immune response, apoptosis, p53 signaling pathway and MAPKKK cascade possibly constituting alternative or subordinate pathways of hematotoxicity and immune toxicity. Gene ontology analysis methods including biological process, cellular components, molecular function and KEGG pathway thus provide a fundamental basis of the molecular pathways through BEs exposure in human lymphoma cells. This may provides a valuable information to do further analysis to explore the mechanism of BE induced hematotoxicity.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1993년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.2-2
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• 1993

The present status of the thennomechanica1 evaluation of functionally gradient materials(FGMs) for space plane application was reviewed, in which research activities and the cooperation of the national project team organized to study FGM science were demonstrated. The project team was divided into three working groups; de singing, processing and evaluation, each of which had their own tasks in the project cooperation. The testings details of the various thennomechanical tests for the FGM samples fabricated by the processing groups were described, along with their corresponding heating conditions of the real environments in the space plane application. For small-sized samples, laser beam heating test and burner heating test were well applied to study the heat shielding and heat resisting properties. Arc-heated wind tunnel test and high temperature!high velocity gas flow test were used for large-sized panel assemblies having cooling structures. The criteria for the evaluation of the heat shielding and heat resisting properties of the FGMs, as well as a crack activation mechanism in their differential temperature heating, were proposed on the basis of the observation in the burner heating test.

• 대한의용생체공학회:의공학회지
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• 제13권3호
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• pp.181-188
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• 1992

This paper provides an overview of system analysis of immunology. The theoretical research in this area is aimed at an understanding of the precise manner by which the immune system controls Infec pious diseases, cancer, and AIDS. This can provide a systematic plan for immunological experimentation by means of an integrated program of immune system analysis, mathematical modeling and computer simulation. Biochemical reactions and cellular fission are naturally modeled as nonlinear dynamical processes to synthesize the human immune system! as well as the complete organism it is intended to protect. A foundation for the control of tumors is presented, based upon the formulation of a realistic, knowledge based mathematical model of the interaction between tumor cells and the immune system. Ordinary bilinear differential equations which are coupled by such nonlinear term as saturation are derived from the basic physical phenomena of cellular and molecular conservation. The parametric control variables relevant to the latest experimental data are also considered. The model consists of 12 states, each composed of first-order, nonlinear differential equations based on cellular kinetics and each of which can be modeled bilinearly. Finally, tumor control as an application of immunotherapy is analyzed from the basis established.

• 한국항해학회지
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• 제4권1호
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• pp.31-50
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• 1980

It does not seem necessarily practicable to keep the system always in optimal condition, athough the control system of the follow-up mechanism on the most marine gyro compasses is to be adjusted by the operator through the gain adjustment. Sometimes a sustained oscillation or an incorrect gyro reading occurs to the system. For such a system any systematical research or theoretical basis of the guide for the optimal gain adjustment has not been reported yet. As a basic investigation of the theoretical system analysis to solve the problems concerned, the author attempts in this paper to express the system in a mathematical model deduced from the results of the theoretical approach and the experimental observation of each element contained in the follow-up mechanism of Hokshin D-1 gyro compass, and to constitute an over-all closed loop transfer function. This funciton being reverted to a fourth orderlinear differential equation, the first order simultaneous differential equations are obtained by means of the state-variables. The latter equations are solved by the Runge-Kutta method with digital computer. By comparing the characteristic of the simulated over-all output with that of the experimental result, it is shown that both outputs are nearly consistent with each other. It is also expected that the system representation proposed by this paper is valid and will be a prospective means in a further study on the design and optimal adjustment of the system.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.215-228
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• 2020

As is shown in the paper, the Koltunov-Rzhanitsyn singular kernel of heredity (when constructing mathematical models of the dynamics problem of the hereditary theory of viscoelasticity) adequately describes real mechanical processes, best approximates experimental data for a long period of time. A mathematical model of the problem of the flutter of viscoelastic plates moving in a gas with a high supersonic velocity is given. Using the Bubnov-Galerkin method, discrete models of the problem of the flatter of viscoelastic plates flowed over by supersonic gas flow are obtained. A numerical method is developed to solve nonlinear integro-differential equations (IDE) for the problem of the hereditary theory of viscoelasticity with weakly singular kernels. A general computational algorithm and a system of application programs have been developed, which allow one to investigate the nonlinear dynamic problems of the hereditary theory of viscoelasticity with weakly singular kernels. On the basis of the proposed numerical method and algorithm, nonlinear problems of the flutter of viscoelastic plates flowed over in a gas flow at an arbitrary angle are investigated. In a wide range of changes in various parameters of the plate, the critical velocity of the flutter is determined. It is shown that the singularity parameter α affects not only the oscillations of viscoelastic systems, but the critical velocity of the flutter as well.