• Journal of Power Electronics
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• v.13 no.6
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• pp.1042-1050
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• 2013

This paper presents a study of maximum power point tracking (MPPT) for photovoltaic arrays with only one current sensor. Initially, a review of MPPT methods with only a current sensor is performed with extension for a variety of dc/dc converters. Furthermore, the same topology is developed to achieve better performance in the presence of sensor offset and environmental noise. The proposed method is robust, cost effective, and behaves well dynamically and in the steady state. After a theoretical analysis of presented approach, its validity and effectiveness are verified by simulation and experimental results.

• Journal of Acupuncture Research
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• v.32 no.3
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• pp.53-60
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• 2015

Purpose : This study aimed to prove that surface electromyography(SEMG) can be used to identify the degree of symptoms of diseases in the upper extremities; it also aimed to confirm various potential therapeutic effects through an inquiry into the value measured by the SEMG on certain acupuncture points in the upper extremities. Methods : Fifty healthy people received instructions for the method of exercise: wrist flexion, extension and hand grasping. Disposable electrodes were attached to acupuncture points of Susamni($LI_{10}$), Naegwan($PC_6$), Oegwan($TE_5$) and below Sohae($HT_3$) two cun on both sides in flexion, extension and grasping to measure the SEMG values. The research results were analyzed using SPSS statistics Ver. 22.0(IBM, USA). Results : The average value was highest on Naegwan($PC_6$) in grasping, and the average SEMG value was higher in the order of grasping, extension and flexion. The asymmetry index of each point was Susamni($LI_{10}$) $16.26{\pm}13.59%$, Oegwan($TE_5$) $20.38{\pm}15.59%$, below Sohae($HT_3$) two cun $20.89{\pm}16.77%$, Naegwan($PC_6$) $22.49{\pm}14.91%$ in wrist extension, Susamni($LI_{10}$) $25.99{\pm}21.44%$, Oegwan($TE_5$) $21.15{\pm}15.94%$, below Sohae($HT_3$) two cun $19.62{\pm}15.46%$, Naegwan($PC_6$) $19.93{\pm}16.85%$ in wrist flexion, Susamni($LI_{10}$) $16.60{\pm}12.21%$, Oegwan($TE_5$) $10.94{\pm}8.29%$, below Sohae($HT_3$) two cun $15.20{\pm}12.60%$, Naegwan($PC_6$) $11.68{\pm}7.77%$ in grasping. Conclusions : In this study, to identify the degree of symptoms of diseases in the upper extremities and confirm therapeutic effects, it is necessary to analyze the calculated percentage and compare the SEMG measurement of special points with those of other points, and with the asymmetry index.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.25-32
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• 2005

PLC is the most widely utilized among many sorts of existing controller for the design of process control system, and study about a PLC language is performed actively. In this paper, we proposed the method that we increase an output points when increased of the output machine which is going to control it in the FA design that used PLC. Output point is going to be extended with 2-3 points in the state that cannot equip output unit in basic base any more. Then an extension base, a power supply, an extension cable and an output unit must be equipped particularly. Then a cost must be added very much. This paper propose the method which extended an output in a small quantity. We designed the expansion unit that received the points of output unit and decoded the signal and the program module that finally extended output points by encoding and decoding, and we confirmed his feasibility through a experiment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1351-1360
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• 1993

The fatigue behavior of GFRP composites is affected by environmental parameters. Therefore, we have to study on effect of sea water on fatigue behavior of GFRP composites as to maintain the safety and confidence in design of ocean structure of GFRP. In this paper, we investigated the fatigue properties of chopped strand glass mat/polyester composite in synthetic sea water. (pH 8.2) In case of the glass fiber (CSM type) reinforced polyester composite materials, the fatigue crack in the both dry and wet specimens tested in air or synthetic sea water occurred at the initial of cycle. Thereafter, it was divided with two regions that one decreased with the crack extension and the other increased with the crack extension. The transition point occurred during the crack propagation shifted to high ${\Delta}K$ value as load increase but its point is not changed regardless of immersion or test environment under a constant load. The synthetic sea water degrades the bond strength between fiber and matrix, thereby the tendency of rapid deceleration and acceleration of the crack growth was appeared.

• Korean Journal of Applied Biomechanics
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• v.28 no.4
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• pp.199-205
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• 2018

Objective: The purpose of this study was to examine the effect of increase in barbell weight on closely related variable to the anterior cruciate ligament (ACL) injury which are knee joint kinematics, joint load, joint moment, and maximum load attainment point during snatch of the weight lifting. Method: The subjects of the study were 10 male Korean national weight lifting athletes (69 kg 5, 77 kg 5; age: $21.80{\pm}3.91yrs.$, height: $168.00{\pm}4.06cm$, weight: $75.00{\pm}4.02kg$, career: $7.8{\pm}3.99yrs.$, snatch records: $168{\pm}4.06kg$). The weight of the barbell during the snatch operation was set at 70%, 75% and 80% of the highest records for each subject studied. Results: The result obtained from the one-way repeated measure ANOVA are as follows: With increased barbell weight, the extension moment of the left knee joint was higher in the 80% condition than the 70% (p<.001). However, other variables were not statistically significant difference. According to the factor analysis of the variables related to maximum load attainment point of the ACL major injury variables, the first sub-factor was the internal shear force, the posterior shear force, the abduction moment, and the muscle activity of the VL. The second sub-factor was the extension moment of the knee joint, compressive force, adduction moment, and the third sub-factor was the muscle activity of BF. Conclusion: These results indicate that the possibility of ACL injury can be lowered when performing a stable snatch movement.

• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.123-130
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• 2015

Wolsong Unit 2,3&4 has been performing a containment integrity test during power operation. This test could impact to the safe operation during test. If an accident occurs during pressure dropping phase, reactor trip can be delayed because of the increased pressure difference which causes a time delay to reach the trip set-point. On the contrary, if an accident occurs during pressure increasing phase, reactor trip could be accelerated because the pressure difference to the trip set-point decrease. Point Lepreau nuclear power plant, which installed GCLMS (Gross Containment Leakage Monitoring System) in 1990, has discontinued the test since 1992 due to these adverse effects. Therefore, we evaluated the risk to obviate the GCLMS test based on PWR's ILRT (Integrated Leak Rate Test) extension methodologies. The results demonstrate that risk increase rate is not high in case of performing only ILRT test at every 5 years instead of doing GCLMS test at every 1.5 years. In addition, the result shows that GCLMS test can be removed on a risk-informed perspective since risk increasement is in acceptable area of regulatory acceptance criteria.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3C
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• pp.264-270
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• 2006

In this paper, we propose the modified display color control system using white point line, boundary lines and S-shaped curves to emphasize blue and red tone colors on CIE1931 diagram. The proposed system divides RGB gamut into movable area and non-movable area by using boundary lines. The colors in movable area are moved into right side or left side along quadratic curve to change the bluish (or reddish) color to more bluish (or more reddish), while those in non-movable area are excepted from color control to prevent skin color from changing. The loci of the quadratic curves are very similar to the arc of the white-point line which connects all points that represent the chromaticities of a black body radiator at different temperatures and is also called the black body locus. The RGB gamut extension by movement of chromaticity coordinate can improve color reproducibility. Therefore in the case of application to LCD, the display shows excellent performance because the LCD's color reproducibility is comparatively lower than that of other display systems. The proposed system is also experimentally demonstrated with Xilinx Virtex FPGA XCV2000E- 6BG560 and the TV set.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.165-173
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• 2014

This study is about determination of fire origin by using analysis of shadow that was recorded CCTV data at the fire scene. This analysis is based on straight and radiate nature of light. At fire experiment with about 1m flame, we conformed that 2-dimensional extension line is focused at the bottom of the fire. If the fire is burning at the same level with shadow, it indicate the point of origin exactly. In 3-dimensional analysis that connect extensional line between distinctive points the shadow and the objet, the line focused in the ${\emptyset}$ 50cm-circle. We estimate the reason of that is because of the character of combustion of gases. The line indicate not the point of origin but the flame that is over the point of origin. thus, you have to consider the line indicate the flame when you do 3-dimensional analysis.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.197-203
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• 2012

In this paper, study the substantial issues which occurs upon free flight environment by performing separation assurance under multiple conflict(over 3 Aircraft), recovery en route under the terms of time constrains and fixed way point after the conflict avoidance, correlations between conflict detection distance and separation assurance by utilizing Autonomous flight algorithm. Result of this experiment demonstrates that the extension of detection distance is advantageous to solution of separation assurance and enhancing of flight efficiency, choose to maneuver by applying time constrain terms and fixed way point according to the situation of conflict prediction in case of recovery maneuver after the conflict avoidance. And separation assurance can be solved by applying 2 degrees or more of bank angle. When choosing the optimal bank angle could be drastically improved flight efficiency.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.345-350
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• 2001

In order to perform elastic-plastic fracture mechanical analyses, fracture resistance curves for concerned materials are required. 1T-CT specimen was used to obtain fracture resistance curves. But the fracture resistance curve by the 1T-CT specimen was very conservative to evaluate the integrity of the structure. And fracture resistance curve was affected by the specimen geometry and crack plane orientation. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the 1T-CT specimen and to provide the additional safety margin. For these, the fracture tests using the real pipe specimen and standard 1T-CT specimen test were performed. 4-point bending jig was manufactured for pipe test and direct current potential drop method was used to measure the crack extension and length for pipe test. From the pipe and the 1T-CT specimen test results, it was observed that the J-integral of the 1T-CT specimen test at the crack initiation point was very small compare to that of the pipe specimen test.