• 한국자동차공학회논문집
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• 제18권5호
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• pp.115-123
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• 2010

Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.

• 한국실내디자인학회논문집
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• 제16호
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• pp.175-181
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• 1998

The purpose of this study was to analyze the characteristics of expression and formal principle of universalism in Architectural Composition. Theorical category is to find universal system with the connection between idea of society and tradition in compositional frame the results were as follows : First it is the pursuit of divine. Through Middle Age and Renaissance universalism of principles in Architectural Composition is appeared a numerical order and human proportion with applying of cosmology. Second it is the pursuit of schema. With the simplicity of formal image it represented to the geometrical form for its clearness. Third it is the pursuit of typology. As to play a role of decisive factor in formal construction type represented the model with abstraction of shape.

• Advances in robotics research
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• 제2권2호
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• pp.151-159
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• 2018

The evolution of bipedal robots was the foundation stone for development of Humanoid robots. The highly complex and non-linear dynamic of human walking made it very difficult for researchers to simulate the gait patterns under different conditions. Simple controllers were developed initially using basic mechanics like Linear Inverted Pendulum (LIP) model and later on advanced into complex control systems with dynamic stability with the help of high accuracy feedback systems and efficient real-time optimization algorithms. This paper illustrates a number of significant mathematical models and controllers developed so far in the field of bipeds and humanoids. The key facts and ideas are extracted and categorized in order to describe it in a comprehensible structure.

• 한국항공운항학회지
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• 제9권2호
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• pp.63-76
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• 2001

The number of civil aviation aircraft registered in Korea has continuously increased. Accordingly the accidents accompanying loss of human or economic resources occurred repeatedly. But the analysis of flight data recorded in FDR was not done by ourselves in the accident investigation because of lack of analysis technology. Therefore, this study is performed to secure the safety of civil aviation by establishing systematic analysis ability of Flight Data Recorder. Through this study, download flight data to personal computer, editing interface file to convert from binary data to engineering data, three dimensional graphical analysis and numerical analysis are performed. For the analysis, the flight of B747-400 model aircraft between Narita(Japan) and Gimpo(Korea) was selected.

• 한국안전학회지
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• 제9권1호
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• pp.89-94
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• 1994

Two methods, the numerical method of CPQRA and the manual method of IAEA, were used to estimate the effect distance from release and dispersion of toxic materials. The Gaussian plume model which has a weather stability class D with wind velocity of 5m/s was applied to calculate dispersion of toxic materials. Also, probit function were employed to evaluate the human fatality as a result of exposure to toxic gases. Furthermore, concentration of toxic materials corresponding to LC$_{50}$ for 30 min could be determined by setting Pr as 5.0 and solving the probit function. Calculations were conducted by employing chlorine and ammonia as toxic materials because they are not only most commonly used In chemical plants but also very harmful to humans. Calculated results by employing toxic materials indicated that the effect distance from the CPQRA method was between the minimum and maximum distance from the method proposed by IAEA.A.

• 대한수학회보
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• 제48권3호
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• pp.555-574
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• 2011

It is well known that the mathematical models provide very important information for the research of human immunodeciency virus type. However, the infection rate of almost all mathematical models is linear. The linearity shows the simple interaction between the T-cells and the viral particles. In this paper, a differential equation model of HIV infection of $CD4^+$ T-cells with Crowley-Martin function response is studied. We prove that if the basic reproduction number $R_0$ < 1, the HIV infection is cleared from the T-cell population and the disease dies out; if $R_0$ > 1, the HIV infection persists in the host. We find that the chronic disease steady state is globally asymptotically stable if $R_0$ > 1. Numerical simulations are presented to illustrate the results.

• 전자공학회논문지B
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• 제33B권2호
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• pp.131-139
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• 1996

This paper describes the chaotic neuron model to represent the complicated states of brain and analyzes the dynamical responses of chaotic neuron such as periodic, bifurcation, and chaotic phenomena which are simulated iwth numerical analysis. Next, the chaotic neuron circuit is implemented w ith the analog electronic devices. The transfer function of chaotic neuron is given by summed the linear and nonlinear property. The output function of chaojtic neuron is designed iwth the two cMOS inverters and a feedback resistor. By adjusting the external voltage, the various dynamical properties are demonstrated. In addition, we construt the chaotic neural networks which are composed of the interconnection of chaotic neuroncircuit such as serial, paralle, and layer connection. On the board experiment, we proved the dynamci and chaotic responses which exist in the human brain.

• Fibers and Polymers
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• 제4권4호
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• pp.169-175
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• 2003

A simulation system for versatile garment drape has been developed. Using this system, the shape of a garment can be simulated in consideration of fabric physical properties as well as the interaction between fabrics and other objects. Each fabric piece in a garment is modeled using a geometrically constrained particle system and its behavior is calculated from an implicit numerical integration algorithm in a relatively short time. The system consists of three modules including a preprocessor for the preparation of fabric patterns and external objects, a postprocessor for the results of three-dimensional visualization, and a drape simulation engine. It can be used for the design process of textile goods, garments, furniture, or upholsteries.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1669-1673
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• 2008

In this study, we simulated the atrial arrhythmia numerically. By using electro-physiological model of atrial cell from Nygren et al. and applying reaction-diffusion partial differential equation, we simulated electrical conduction in atrium. A 3-D mesh system representing the human atrium was reconstructed from the surface geometry of atrium. We used a stimulus in the form of an archetype around pulmonary vessels in the left atrium to cause the atrial arrhythmia. The septal atrial tarchycardia was developed after the stimulus.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2410-2414
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• 2008

Human heart valves diseased by congenital heart defects, rheumatic fever, bacterial infection, cancer may cause stenosis or insufficiency in the valves. Treatment may be with medication but often involves valve repair or replacement (insertion of an artificial heart valve). Bileaflet mechanical heart valves (BMHVs) are widely implanted to replace the diseased heart valves, but still suffer from complications such as hemolysis, platelet activation, tissue overgrowth and device failure. These complications are closely related to both flow characteristics through the valves and leaflet dynamics. In this study, the physiological flow interacting with the moving leaflets in a bileaflet mechanical heart valve (BMHV) is simulated with a strongly coupled implicit fluid-structure interaction (FSI) method which is newly organized based on the Arbitrary-Lagrangian-Eulerian (ALE) approach and the dynamic mesh method (remeshing) in FLUENT. The simulated results are in good agreement with previous experimental studies. This study shows the applicability of the present FSI model to the complicated physics interacting between fluid flow and moving boundary.