• 연구논문집
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• s.23
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• pp.73-80
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• 1993

This study presents an intelligent PID control method based on the fuzzy logic and this method is applied to the active magnetic bearing system. By using an appropriate fuzzy matrix, some changes of values of the three coefficients of the controller are determined during system operation and these lead to the improvement of the transient and steady state behavior of the closed loop system. The presented method is actually a combination of the principles of PID control and fuzzy logic. Since the fuzzy logic using linguistic variables in place of numeric variables has many points of likeness to the human logic, the improvement in performance is notable especially in case of large nonlinearity and uncertainty such as the controller start and the excessive mass unbalance. A set of simulation and experimental results illustrate and considerable improvement in the control performance including small overshoot and small transient currents in magnet coils, while maintaining the overal static and dynamic characteristics near the equilibrium position.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.171-174
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• 1992

Development of a noninvasive intensive care system calls for the use of evoked potentials (EPs), as a means of diagnosing traumatic head-injured patients. The experiment entails surgically plating two subarachnoid bolts and a subdural balloon through the skull to simulate a subdural hematoma. Using various levels of intracranial pressure (ICP) and/or different sizes of balloons, auditory evoked potentials (AEPs) were recorded from a rabbit. Six positive peat latencies ($P_1-P_6$) and five negative peak latencies ($N_1-N_5$) were extracted from an averaged AEP waveform. Multiple regression analyses were performed for determining a relationship between the ICP and AEP peak latencies. The results indicate that a major correlation of changes on AEP peak latencies is due to mechanical forcer of a mass (inflated balloon simulating a hematoma) in the distortion of the brain matter rather than increased ICP.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.198-201
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• 1997

The new system for identification of organic vapours and analysis method of mechanism between organic vapours and sensitive materials were attempted using the resonant resistance and resonant frequency of Quartz Crystal Analyzer (Q. C. A.). The resonant resistance shift means rheological changes in sensitive LB films occurred by the adsorption of organic vapours, while the resonant frequency shift represent the mass of organic vapour loaded in or on the sensitive LB films. It is thought that we can obtain more accurate response mechanism of organic vapour using the resonant frequency and resonant resistance diagram. The polymeric sensitive material were quantitively depositied using the LB method. In the experimental results, the adsorption behavior of organic vapour response can be decided by two type ; surface adsorption and penetration into sensitive material. Organic vapours had different positions in the Frequency-Resistance (F-R) diagram as to the kinds and concentrations of organic vapours. Thus F-R diagram can be applied to the development of one channel gas sensing system using the Quartz Crystal Analyzer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.155-164
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• 1998

A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the dynamic response of heat pump. First, a basic heat pump cycle is examined at steady state to show the general trends of exergy changes in each process of the cycle. Entropy generation issue in the exchangers is discussed to optimize the heat pump cycle. Second, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Third, the exergy destruction rate associated with the ON/OFF operations of the heat pump is calculated by simulating the thermodynamic states of the condenser and the evaporator. The inefficiency of the ON/OFF operation during the transient period is quantitatively revealed by the exergy analysis.

• Journal of Korean Society of Rural Planning
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• v.21 no.2
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• pp.1-10
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• 2015

This study consists of an observation of the changes in management and agricultural production of Shinbuk-eup based on the data from the Agricultural, Forestry & Census Report Survey. The following is a short summary and suggestions of the research. First, taking a look at the farming conditions of Shinbuk-eup, it shows that it is extremely polarized into rice paddies and vegetable cropping. Second, using the Tobit model to analyze the factor of determination of farmable lands of the farmers in Shinbuk-eup, the higher the number of family members, the less the hired work, and the more the experience in farming, have larger farmable lands. Meanwhile, the younger the farmer, their land mass is higher, however, after reaching their threshold age, their lands decrease.

• Proceedings of the KSRS Conference
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• v.1
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• pp.328-331
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• 2006

Eight years of SeaWiFS data quantify variability in the time/space patterns of spring bloom development in the Gulf of Maine (GOM). Maximum and earliest spring bloom are usually observed over Georges Bank, later on the deep basins from the west to the east GOM, and latest development along the eastern Maine coast in cold, tidally mixed water. Pronounced interannual variability of spring bloom timing, spatial position, and magnitude are shown in the GOM. Strongest negative anomalies are present in April 1998 and 2001 over Georges Bank and the eastern GOM, and in January to April of 2005 over the most of GOM. Positive anomalies are strong in April 2001, 2003 and 2004 in varying locations as well as in February and March 1999. It is suggested that interannaul variability in spring phytoplankton bloom concentrations is strongly associated with changes in water mass and stratification which might be influenced by basin-scale forcing due to large climate change.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.391-398
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• 1990

The intradermal injection of Propionibacterium acnes (ATCC 6919) into the ears of female Sprague-Dawley rats produced a chronic inflammation with the formation of acneiform lesions. Inflammation was characterized by more than four times of ear thickness and 2.8 times of ear weight at day 21. Histologically, massive infiltration of neutrophils, macrophage and lymphocytes, hyperplastic epidermis, comedones containing keratin mass and inflammatory materials were observed. Both ginseng saponin and extract from Korean red ginseng significantly redliced the ear thickness and their effects were similar to that of benzoyl peroxide. Ginseng samples and beneoyl peroxide modified lipid constituents of P. acnesinjected rat ear tissues. Even though no marked histological changes in inflammatory lesions were observed in ginseng-treated ear tissues, Korean red ginseng showed a possibility of reduce in the risk of acne development.

• Selected Papers of The Society of Naval Architects of Korea
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• v.2 no.1
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• pp.47-62
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• 1994

Herein the surge-heave-pitch motion of a ship in harbor has been analyzed within the framework of linear potential theory. The ship is assumed to be slender and moored at an arbitrary position in a rectangular harbor with a constant depth. The coast line is assumed to be straight. The ship and harbor responses to incident long waves are represented in terms of Green's function, which is the solution of tole Helmholtz equation satisfying necessary boundary conditions. An integral equation is obtained from matching condition between harbor and ocean solutions, and it is replaced by an equivalent variational form. Numerical results sallow that the ship motion can be highly amplified at the frequencies, where the harbor is resonated by the incident wave. At the resonant frequencies, the added mass for vertical motions becomes negative and the damping forte changes abruptly.

• Journal of Korean Medicine for Obesity Research
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• v.9 no.2
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• pp.1-10
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• 2009

Objectives This study was performed to find out the effects of obesity educational program on blood lipid profile and body composition on overweight elementary school students. Methods Twenty-five overweight elementary school students were recruited in 2009. Pilates exercise(9 times, twice per week), two smile theraphie, and nutrition consults were underwent for two months. Anthropometry, bioelectrical impedance analysis, and blood test have been done before and after the program. Result There were significant changes in height, weight, waist circumference, body mass index, and percent body fat after the program. Conclusion The obesity educational program which were consisted of pilates exercise, smile theraphies, and nutrition consults had effects on overweight elementary school students' losing weight and improving lipid profile.

• Structural Engineering and Mechanics
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• v.8 no.5
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• pp.453-464
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• 1999

Safety monitoring systems of structures generally resort to detecting possible changes of dynamic system parameters. Sensitivity analysis of these dynamic system parameters may implement these techniques. Conventional structural eigenvalue problems are discussed in the scope of those systems with deterministic parameters. Large and flexible structures, such as suspension bridges, actually possess stochastic material properties and these random properties unavoidably affect the dynamic system parameters. The sensitivity matrix of structural modal parameters to basic design variables has been established in this paper. Moreover, second order statistics of natural frequencies due to the randomness of material properties have been discussed. It is concluded from numerical analysis of a modem suspension bridge that although the second order statistics of frequencies are small relatively to the change of basic design variables, such as density of mass and modulus of elasticity, the sensitivities of modal parameters to these variables at different locations change in magnitude.