• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.449-454
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• 2006

We present a pressure sensor based on the mechanically induced long-period fiber gratings (LPFG) for detecting the multi-location strain variation. The theoretical analysis is performed using a graphic method for a weakly guiding step-index fiber. The calculated results are in good agreement with the experimental results. In this study, from the fact that the optical parameters of a single-mode fiber slightly differ from manufacturing company to manufacturing company, the multipoint pressure-detection sensor systems composed two identical LPFGs are realized. When the pressure is applied two LPFG sensors at once, the resonance peaks are separated as much as about 40 nm. These types of sensor systems are well suited as a multipoint monitoring of strain or temperature in the ship or the smart structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.199-202
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• 2011

플로팅구조물은 열악한 해양환경상태에 있기 때문에 구조물응답에 대한 실시간 모니터링 기술을 적용하여 구조안전성을 확보해야 한다. 특히 기존의 전기 저항식 스트레인 게이지 단점을 극복한 광섬유 센서를 이용하여 실시간 모니터링 시스템 개발에 관한 연구가 필요하다. 본 논문에서는 플로팅구조물의 축소 모델에 광섬유 센서 중 하나인 FBG센서를 부착하고 실험용 수조에 설치하여 광학 스펙트럼 분석기를 통해 중심파장을 측정한 후 변형률을 계산하였다. 또한 유한요소 모델을 유한요소 해석 프로그램인 ABAQUS를 사용하여 모델링하고 유한요소 해석을 통해 변형률을 출력하고 실험결과와 해석 결과를 비교하여 광섬유 센서를 이용한 플로팅구조물의 실시간 모니터링을 위한 기초자료를 제공하고자 한다.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.1-4
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• 2011

The full spade rudder for the high speed has advantage to prevent gap cavitation of the rudder. DSME has developed the full spade rudder and GL has carried out CFD analysis and FE analysis to confirm strength and fatigue for DSME and Owner. Necessarily, it needs to compare rudder torque & rudder force between CFD, FE analysis and full scale measurement. This report introduces the measurement method and application of strain gauge for measuring the rudder torque and rudder force for the 8,400 TEU container ship.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.925-931
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• 2009

This paper reports a preliminary experimental investigation and characterization of an optical fiber-based submersion sensor system for applications in water flooding and leakage. The sensor system comprises a multi-mode fiber spliced with fiber Bragg grating and an intensity-based interrogator. Submersion tests were conducted in water-air and Glycerin-air environments. By the refractive index of the fiber-probe surrounding materials, the reflectance and the detecting power level is determined. When the probe is dipped into the water, the optical output power dramatically decreases from -7.5dBm to -17.5dBm. But, the center of Bragg wavelength is not affected in spite of external material changes. Temporal response characteristics of the sensor system is investigated to verify the real-time reaction. When the probe is immersed into the liquid, there is no transition time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.153-153
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• 2018

In this paper, we have represented basic experiment results for the application of electric vehicle powerline communication using an induction type coupler. The coupler was fabricated using nano-crystalline alloy and it was applied to the charging system of electric vehicles to measure the communication performance. Experimental results showed a channel bandwidth over 48 Mbps.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.154-154
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• 2018

Conventional inductive powerline communications typically use ferrite cores. However, since the recent nanocrystalline cores are expected to perform better, this paper aims to measure the performance of inductive couplers using nanocrystalline cores. To do this, we used inductive powerline communications to observe the communication range when increasing the number of cores from one to five. This experiment shows that we have the best communication performance when we connect 5 cores.

• Journal of Sensor Science and Technology
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• v.18 no.3
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• pp.245-250
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• 2009

The paper presents the wireless wind chill temperature measurement system that is composed of IEEE 802.15.4 standard wireless communication devices, hot film anemometer and serial communication temperature sensor. It's sometimes very difficult for a person, who lives in a high-rise apartment, to see the outside wind chill temperature due to harsh outside weather. The wind chill temperature is calibrated from an air velocity and air temperature. IEEE 802.15.4 standard wireless communication is ZigBee compatible, and consumes low power in communication. Under the air temperature of 5 $^{\circ}C$ and air velocity ranging from 0 to 50 km/h, the experimental result of wind chill temperature shows good accuracy within 5%.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.184-190
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• 2010

In this paper, a remote submersion warning system based on multi-mode optical fiber(MMF) sensors and a wireless sensor network(WSN) are proposed. To improve the reliability and stability of the sensors, the dual optical fiber sensors combined to the optical coupler are demonstrated. A slave zigbee as a wireless sensor module was used as a platform to monitor and record the signal from the MMF sensors and then transmits these information to a master zigbee wirelessly. The monitoring system running the $LabVIEW^{(R)}$ software was connected to the internet to support the short message service(SMS) through extensible markup language(XML) web service. No matter where the managers are, they can always receive the real-time remote-monitoring data for safety check.

• The Journal of Korean Medicine
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• v.27 no.3 s.67
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• pp.212-221
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• 2006

Objectives: This study was designed to investigate acupuncture treatment of alopecia patients by researching literature and to standardize acupuncture treatment. Methods: We extracted the parts about acupuncture treatment of alopecia which are called 'Tal Bal(說髮), 'Ban Dok'(斑禿), 'Tal Mo'(脫毛), 'Bal Rak'(髮洛), 'Wonhyung Talmo'(圓形脫老) from 2 ancient and 49 modern oriental medicine literal sources. We surveyed the frequency and characteristics of the acupoints used for treatment of alopecia, and the acupoint was classified according to its meridian or demonstration. The results of this study were recorded as follows: 1. The most frequently used acupoints were GB20(風紙), GV20(百會), BL13(膈兪), SP6(三陰交), ST36(足三里), BL23(腎兪), SP10(血海), LI11(曲池), in that order. 2. The most frequently used meridians were the urinary bladder meridian (足太湯膀胱經), the Governor Vessel(督豚), the spleen meridian(足少陰脾經), and the gall bladder meridian(足少陰膽經), in that order 3. The most frequently used regions were the head, under the knee, and the back, in that order. 4. The most frequently used Jang organs and Bu organs were the spleen(脾), the stomach(胃), the liver(肝), the gall bladder(擔), the lungs(肺), and the large intestines(大腸), in that order. 5. Common methods of differentiation of alopecia are Hyulyulsaengpung(血熱生風), Gichehyutea(氣滯血瘀), Gihyulyanghea(氣血兩瘀), and Gansinbugok(肝腎不足). Conclusions : For treatment of alopecia, all the patient's symptoms, including alopecia, must taken into consideration and demonstrated.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.9 no.1
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• pp.69-83
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• 2005

Background and purpose: The purpose of this study is to review the recent achievements on ryodoraku and suggest new ryodoraku studies. Methods: The study papers related with ryodoraku, published in foreign countries and Korea up to the present, were collected first by internet search & journal. And then the collected papers were classified and summarized. Results and Conclusion: There are three study trends. One is finding some effect and analysis for some symptoms, another is finding a distinguishing mark and a diagnostic index, and the other is raising several points & providing solution & studying about relativity with another diagnosis. Some studies finding some effect and analysis for some symptoms are to be classified into four items(1. effect of drugs medication. 2. effect of ryodoraku therapy. 3. effect of other treatments. 4. effect of other treatments with ryodoraku therapy). Other studies finding a distinguishing mark and a diagnostic index are to be classified into two items(1. diagnostic index of symptoms. 2. distinguishing mark of disease). The other studies are to be classified into three items(1. ryodoraku introduction and raising several points at issue. 2. improvement machinery and tools. 3. studying about relativity with another diagnosis). Finally we need solving the ryodoraku problems(the condition of measurement and reproducibility, relation with Kyung-rak(經絡) and Ryodoraku, the reason of Ryodoraku points producing and etc.).