• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.294-299
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• 2009

The purpose of this research was to find out the housing history of Sakhalin returnees since leaving hometown under the Japanese ruling period. Face to face interview had been done with 20 returnees in the community center during October to December, 2008. Personal life as well as housing histories were differed by the reason to move into Sakhalin, which still influenced the returnee' life in Ansan. The housing they had lived changed from barracks like a training camp, to Japanese small wooden cottage/row house, and then Russian brick house/apartment. Housing alteration and addition were common to renew the old house. The boundary of residing area was mostly limited to the first residing location throughout one's life without a long distance move. Housing satisfaction was very high in Gohyangmaeul because of the improvement of housing facilities and residence itself as well as convenience of housing management compared to the residence in Sakhalin. Economic and emotional aspect of life satisfaction were also high through about 8 years of living in. Forced movers still require the compensation on hand no matter the amount.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.733-740
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• 2016

To achieve bipedal walking in real human environments, a bipedal robot should be capable of modifiable walking both on uneven terrain with different heights and on flat terrain. In this paper, a novel walking pattern generator based on a 3-D linear inverted pendulum model (LIPM) is proposed to achieve this objective. By adopting a zero moment point (ZMP) variation scheme in real time, it is possible to change the center-of-mass (COM) position and the velocity of the 3-D LIPM throughout the single support phase. Consequently, the proposed method offers the ability to generate a modifiable pattern for walking on uneven terrain without the necessity for any extra footsteps to adjust the COM motion. In addition, a control strategy for bipedal walking on uneven terrain with unknown height is developed. The torques and ground reaction force are measured through force-sensing resisters (FSRs) on each foot and the foot of the robot is modeled as three virtual spring-damper models for the disturbance compensation. The methods for generating the foot and vertical COM of 3-D LIPM trajectories are proposed to achieve modifiable bipedal walking on uneven terrain without any information regarding the height of the terrain. The effectiveness of the proposed method is confirmed through dynamic simulations.

• Laser Solutions
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• v.15 no.2
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• pp.15-20
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• 2012

A novel joining technology was developed to compensate the camber in polymers. The preheating laser beam circulates on the joining location and the accumulated heat serves to increase the flexibility of neighboring polymers. The temperature rises up to the glass transient temperature of the polymers and continually loading spring force closes the gap of camber. The irradiated laser was 808nm central wavelength and the power varied between 2Watt and 5Watt. The laps were adjusted between 3 and 10 and the optimum process parameters were 3Watt and 5 laps for the specific application. An FEM analysis was introduced to understand the mechanism of joining by the transient temperature distribution on the polymers. Thermocouples experiments were also tried to correlate the numerical analysis results and it showed the trend of heat accumulation in experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.43-48
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• 2001

In conventional wind generation systems, since the blade rotates at low speed when the velocity of wind decreases their operations are possible only under limited conditions. Therefore they are in trouble of self-generation without the help of auxiliary generation devices outside. In addition, most of them have very low usage efficiency because of the characteristic changes of wind. For the solution of these problems and for enough generation regardless of districts and geographical features the rotation energy stored in a spring drives a compact generator and then electric power is stored at battery and supplied to the load continuously according to the lack of wind force. In this paper, the fabricated system consisting of a wind generator and power storage apparatus was introduced and its operation characteristics were analyzed.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.132-137
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• 2022

In this paper, we have studied the quadrature error reduction for the single drive 3-axis MEMS Gyroscope. There was a limitation of the previous study which is the z-axis quadrature error was large. To reduce this value, design methodologies were presented. And the methodologies included a different mesh application, z-rate spring structure change, and mass compensation for balancing of the structure. We conducted the modal analysis, drive mode analysis and sense mode analysis using COMSOL Multiphysics. As a result, a drive resonant frequency was 26003 Hz, with the x-sense, y-sense, z-sense being 26749 Hz, 26858 Hz, 26920 Hz, respectively. And the Mechanical sensitivity was computed at 2000 degrees per second(dps) input angular rate while the sensitivity for roll, pitch, and yaw was computed 0.011, 0.012, and 0.011 nm/dps respectively. And z-axis quadrature error was successfully improved, 2.78 nm to 0.95 nm, which the improvement rate was about 66 %.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.1
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• pp.28-41
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• 2024

The carbon balance serves as a valuable indicator of a plant's physiological status under diverse environmental conditions. We investigated the photosynthetic and respiratory responses of the Asian surfgrass Phyllospadix iwatensis along the northeast coast of the Korean peninsula in response to changing water temperature (ranging from 5℃ to 30℃) to estimate the seasonal whole-plant carbon balance through a series of incubation experiments. The maximum gross photosynthetic rate (P_max) showed a significant difference among the temperature treatments, while there was no significant difference in photosynthetic efficiency (α). The maximum gross photosynthetic rate of P. iwatensis reached its peaks at 20℃ treatment (101.65 μmol O₂ g^-1 DW h^-1) but decreased rapidly at 30℃. The saturation irradiance (I_k), compensation irradiance (I_c), and respiration rate (R) of P. iwatensis exhibited significant differences among the temperature treatments. The saturation irradiance increased up to 20-25℃ (121.59-124.50 μmol photons m^-2 s^-1) and sharply decreased at 30℃. The compensation irradiance and respiration rate increased steadily with rising water temperature. The ratio of P_max to R (P_max:R ratio) was the highest at 5℃ but dramatically decreased at 30℃. The whole-plant carbon balance, calculated based on photosynthetic parameters, respiration rates, and biomass, exhibited distinct seasonal variation, increasing during winter and spring and decreasing during summer and fall, which is consistent with the highest in situ growth in spring and severely limited growth at the highest water temperature conditions. Phyllospadix iwatensis displayed a negative carbon balance during late summer, fall, and winter, but demonstrated a positive carbon balance during spring and early summer. Our findings suggest that the rising seawater temperatures associated with climate change may lead to significant alterations in the seagrass ecosystem functioning along the rocky shores of the Korean east coast.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.426-433
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• 1986

This experiment was carried out to investigate the competitive ability and the interaction of each species in ten mono-and binary-associations of four forage species; orchardgrass, tall fescus, ladino clover, and alfalfa. Each species was grown in intra- and interspecific stands in large pots for one year. And samplings of shoot and root were taken in Spring, Summer, and fall clipping stages. Intra- and interspecific competition was compared and evaluated by expected yield, aggressivity, relative yield total(RYT), compensation index(CI), general combining ability(GCA), and specific combining ability (SCA) with shoot and root dry matter production of each species in monoculture and binary mixture. The forage yield was high in two grass species and the mixture of them, but low in two legume species and the mixture of them. The mixture of tall fescue-ladino clover was evaluated as a productive association with a high PYT(1.05) and a high SCA(0.79), and tall fescue was a more aggressive species in it. Each of grass-grass and legume-legume mixture was less aggressive between two species and lower SCAs than grass-legume mixtures. Especially, orchardgrass was the most agressive species and alfalfa was the least, but tall fescue had the highest GCA and ladino clover had the lowest in shoot competition. Also in root, tall fescue- ladino clover mixture was a good match with a high RYT(l.12) and a high SCA (0.60), and orchardgrass was highest in aggressivity. However, orchardgrass had the highest GCA in root while tall fescue had the highest in shoot.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.224-229
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• 1982

Effects of light intensity and temperature on photosynthesis and respiration of autogenous wild SUMBODY plants, Dystaenia takesimana, known as a prospective source of forage in Ulleung island, Korea, were investigated. Results were as follows : 1. Light saturation point at $20^{\circ}C$ was 34 to 38 klux and light compensation point was 4 to 6 klux. Apparent photosynthetic rate at light saturation was 9 to 12 mg $CO_2/dm^2/hr$. 2. Optimum temperature for photosynthesis was $20^{\circ}C$ and $Q_{10}$ values of two temperature ranges, 20 to $30^{\circ}C$ and 30 to $40^{\circ}C$, were 0.8 and 0.9 for photosynthesis, while $Q_{10}$ for respiration were 1.6 and 1.7. 3. Native plants sampled in area of higher altitude had a higher apparent photosynthtic rate at lower temperature and the plants sampled in area of mixed with bushes had lower a light compensation point. These rusults suggest that the Inland weather condition of Korea during spring and fall seasons might be. suitable for the SUMBODY growth but inadequate during summer.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.24-34
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• 2001

The authors reconstruct a mooring type underwater positioning system to measure the movement of bag-net in a set-net by long base line mode with four transponders attached on the bag-net in latitudinal and a transponder fixed on the sea bed. To confirm the practical use of the system, the field experiments were carried out at the Jaran Bay, Kosung, Kyungnam Prov., on October 6, 2000 (neap tide) and November 28, 2000 (spring tide). And the vertical oscillation of bag-net was observed with three data loggers attached on the bottom of bag-net in longitudinal on November 28, 2000. The longitudinal movement range, the latitudinal one and the vertical one of the bag-net were 3.2 m, 3.4 m and 2.1 m. respectively. At the spring tide, these variations were 7.8 m, 7.8 m and 5.0 m, respectively. The vertical oscillation range about the bottom of the bag-net at near point of the slope net, at the middle part and at far point from the slope net were 3.2 m, 3.7 m and 8.4 m, respectively. The depth of the bottom net was decreased and its vertical oscillation appeared frequently when the current speed was more than 10 cm/s and the current direction was significantly different from the longitudinal axis of the bag-net. The variation of hydrophone coordinates measured by the transponder fixed on the sea bed presents that hydrophones equipped to the frame line of the set-net could be moved within several meters due to the tidal current. The fact indicates that the compensation of hydrophone coordinates is necessary to reduce the measuring errors. The position measuring errors of x, y and z axis of the system measured in the cage of aquaculture were 0.6 m, 0.8 m, and 1.2 m, respectively. And the errors of the transponders those were close to the base lines or placed in the baselines were smaller than those of others.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1141-1146
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• 2014

As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.