• 한국통신학회논문지
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• 제27권12C호
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• pp.1299-1305
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• 2002

본 논문에서는 위성통신용 송수신 안테나 시스템을 위한 배열 안테나를 설계하고, 이를 제작하여 그 결과를 검증한다. 본 논문에 제시된 안테나는 하나의 마이크로스트립 패치 소자로 송/수신을 겸용하기 위하여 광대역 특성을 가지며, 송/수신 주파수 대역에서 각각 우원편파와 좌원편파로 동작하도록 설계하였다. 특히 광대역 특성을 얻기위해 적층 기술을 이용하였고, 원형편파 생성을 위해 truncated square 형태의 정사각형 소자를 이용하였으며, 2$\times$1 시퀀셜 로테이션 배열 방식을 적용하여 대역폭 특성을 더욱 개선시켰다. 설계 결과에 대한 타당성을 검증하기 위하여 8$\times$1 마이크로스트립 배열 안테나를 제작 및 측정하여 시뮬레이션 결과와 비교하였으며, 측정결과는 시뮬레이션 결과와 거의 일치함을 보였다.

• 한국운동역학회지
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• 제15권4호
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• pp.97-104
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• 2005

Previous studies of kinematic analysis of golf swing usually dealt with variations vertically. The purpose of the study was to examine the horizontal hip joints motion of the fifteen male professional golfers during driver swinging. Kinematic variables were calculated by the Kwon3D motion analysis program. Paired t-tests and one-way ANOVA were used to compare the hip height, distance, displacement, and position differences. Results showed that there were no hip height changes and no hip height differences between left and right hip from address to impact. The axis of the backswing was braced right hip, the axis of the downswing was moving left hip. Hips position at the top of the backswing showed that hips move to target prior to hands, which means the sequential motion of the chain linked body segments. From address to impact, left hip moving distance was longer than right hip(p<.001), but during the whole swing, right hip moving distance was longer than left hip(p<.001). Hip rotation angle to target line was $-48.14{\pm}9.32^{\circ}$ at top of the backswing, $40.88{\pm}8.44^{\circ}$ at impact, and $104.70{\pm}8.14^{\circ}$ at finish.

• 대한약침학회지
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• 제3권2호
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• pp.213-232
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• 2000

Hemiplegic shoulder pain(HSP) is one of the most frequent and difficult problems affecting poststroke hemiplegic patients. Honeybee venom acupuncture therapy(BVAT) is known for its pain relieving effects in arthralgia. To evaluate the effectiveness of BVAT on HSP, 24 patients were sequential1y allocated into BVA T treatment group and control group and monitored for 4 weeks at time interval of initial(T0), 1 week(T1), 2 weeks(T2) and 4 weeks(T4). In treatment group, 1:10000 honeybee venom solution 0.2㎖ was injected into acupoint(s) following Deqi three times a week. Kyonu(LI15) was used in the first week. Thereafter Kyonu(LI15) and Nosu(SI10) were used. Visual analogue scale of pain severity showed significant decrease in treatment group compared to control group at T2 and T4 evaluation. Painless passive range of motion of shoulder external rotation showed significant increase in treatment group compared to control group at T4 evaluation. Fugl-Meyer Motor Assessment of upper limb motor function and Modified Ashworth scale of the spasticity of upper limb showed no difference between two groups. BVAT showed as an effective therapy in HSP and further extensive clinical studies are expected.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.776-781
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• 2004

We report the performance of a four-element, 11.67 GHz, $high-{T}_c$ superconducting (HTS) microstrip antenna array with corporate feed network. The HTS antenna array used in this work had a circular polarization for direct broadcasting satellite (DBS) system. Our array antennas were designed and built on a 0.5 mm thick MgO substrate. To compare the superconducting antennas with normal conducting counterpart, One antenna pattern was fabricated from gold thin film, and a second pattern was fabricated from ${YBa}_2{Cu}_3{O}_7-x(YBCO)$ superconducting thin film. To improve the axial ratio of circularly polarized arrays, sequential rotation technique were used. Efficiency, radiation pattern, return loss and bandwidth were measured for both antennas at cryogenic temperature and room temperature. The array produced good circular polarization, and the gain of the array at 77 K, relative to a copper array at room temperature was approximately 1.54 dB. The measured return loss of our HTS antenna array was 35.79 dB at the resonant frequency of 11.67 GHz and The total effective bandwidth was about 3.4 %. The results showed that high-temperature superconductors, when used in microstrip arrays, improved the efficiency of the HTS antenna array for circularly polarization.

• 전기학회논문지
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• 제67권6호
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• pp.782-788
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• 2018

This paper proposes a novel method for the omnidirectional camera-based image rendering synchronization system using head mounted display. There are two main processes in the proposed system. The first one is rendering 360-degree images which are remotely photographed to head mounted display. This method is based on transmission control protocol/internet protocol(TCP/IP), and the sequential images are rapidly captured and transmitted to the server using TCP/IP protocol with the byte array data format. Then, the server collects the byte array data, and make them into images. Finally, the observer can see them while wearing head mounted display. The second process is displaying the specific region by detecting the user's head rotation. After extracting the user's head Euler angles from head mounted display's inertial measurement units sensor, the proposed system display the region based on these angles. In the experimental results, rendering the original image at the same resolution in a given network environment causes loss of frame rate, and rendering at the same frame rate results in loss of resolution. Therefore, it is necessary to select optimal parameters considering environmental requirements.

• 한국전자파학회논문지
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• 제13권4호
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• pp.393-400
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• 2002

본 논문에서는 원형편파를 발생시키기 위한 여러 가지 방법 중 단일 급전 십자개구 결합 방식이 가지는 협대역의 축비 대역폭을 개선하기 위해 단일 급전으로 하이브리드 급전의 효과를 가져을 수 있는 직렬 급전 십자개구 결합 마이크로스트립 안테나를 제안하고, 기존에 발표된 단일 급전 십자개구 결합 안테나와의 축비 대역폭, 이득, 방사패턴, 그리고 임피던스 대역폭 등과 비교하여 개선된 축비 대역폭 특성을 제시하여 제안된 안테나의 타당성을 보였다. 또한 제안된 단일 안테나를 이용해 2$\times$2 배열 안테나로 확장하는 과정에서 시퀀셜 로테이션 기법을 적용함으로써 더욱 넓은 축비 대역폭을 화보할 수 있도록 하였다. 직렬급전 단일 안테나와 2$\times$2 배열 안테나의 측정된 축비 대역폭은 110 MHz(4.6 %)와 420 MHz(17.5 %)를 보였고, 측정된 임피던스 대역폭 (VSWR<1.5)은 240 MHz(10%)와 500 MHz(20.8%)출 가졌으며, 이득 측정결과에서는 단일 안테나와 2$\times$2 배열 안테나 모두 3 dB 이득 대역폭에서 400 MHz(16.7%) 이상의 평탄 특성을 가지며 최대이득에서는 8.2 ㏈i와 12.5 ㏈i의 이득특성을 보여주었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.297-302
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• 2007

Vibrating test of vehicle component can be possible in lab-based simulators instead of field testing owing to the development of technology in control algorithm as well as computational process. Currently, Multi-Axial Simulation Table(MAST) is recommended as a vibrating equipment, which excites a target component for 3-directional translation and rotation motion simultaneously and hence, vibrational condition can be fully approximated to that of real road test. But, the vibration-free performance of target component is not guaranteed with MAST system, which is only simulator subjective to the operator. Rather, the reliability of multi-axial vibration test is dependent on the quality of input profile which should cover the required severity of vibrating condition on target component. In this paper, multi-axial vibration testing methodology of vehicle component is presented here, from data acquisition of vehicle accelerations to the obtaining the input profile of MAST using severe data at proving ground. To compare the severity of vibration condition, between real road test and proving ground one, energy principle of equivalent damage is proposed to calculate energy matrices of acceleration data and then, it is determined the optimal combination of special events on proving ground which is equivalent to real road test at the aspects of vibration fatigue using sequential searching optimal algorithm. To explain the vibration methodology clearly, seat and door component of vehicle are selected as a example.

• 정보과학회 논문지
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• 제42권6호
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• pp.748-754
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• 2015

본 연구에서는 다중 상태 변수의 인수 HMM을 일반화하여 연속 은닉 변수와 이산 은닉 변수가 결합된 순차 상태 추정 모형을 제안하고 이에 기반한 보행 동작 모형을 설계한다. 유한 상태의 이산변수는 마르코프 연쇄 구조로 보행의 동역학적 특성을 표현하고 각 이산 상태에 대해 연속 변수를 독립변수로 한 가우스 과정을 정의한다. 마르코프 상태 천이는 여러 가우스 과정 사이의 스위칭을 제어하며 각 가우스 과정은 동일한 자세의 회전 또는 다양한 시각을 표현한다. 온라인 필터링 추론을 위해 입자 필터 방식의 추론 알고리듬도 제시한다. 이 알고리듬은 입력 벡터 열이 주어졌을 때 이들 병렬적 가우스 과정을 동적으로 갈아타는 스위칭 궤적을 디코딩 해준다. 실험 결과 비선형적 보행자 비디오 영상을 보행방향과 보행 상태의 열로 분리하며 매우 직관적인 해석을 할 수 있음을 보였다.

• 한국조경학회지
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• 제30권2호
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• pp.1-11
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• 2002

The purpose of this study is to investigate landscape image and define elements of difference in visual preference of bridges on the Han River. To do this end, video was used as a media for the evaluation of the landscape image of 16 bridges on the Han River using a Semantic Differential scale. Data is collected by 50 students from Woosuk University, majoring landscape architecture. Final analysis utilized a total of 704 samples of data. Data is analyzed through descriptive statistics, and spatial image is analyzed by factor analysis algorithm Principle component analysis using Varimax method is applied far extraction and factor rotation. T-test is used to find the difference between the bridge type of preference with the data of factor score. Logistic regression is used to select the factors that influences the visual preference among the image factors. The results of this study can be summarized as follows; The image of whole bridges on the Han River is somewhat orderly, sequential and open. The degree of visual preference of unique bridge type is higher than normal but there are some differences in visual preference within the same type of structure. This suggests that the surrounding landscape is one of the important factor for visual preference. Factors covering the image of bridge are found to be 'aesthetic',　'structure','spatial factor', and 'shape'. Total variance is obtained as 60.4%. The aesthetic variables are the most important factor for visual preference and the structural factor presents no significant difference in visual preference between more preferred and less preferred bridges. Since the collapse of Songsu Bridge, we thought the structural factor is very important but the results of this study suggest that it is more important to consider the aesthetic and spatial factors of the bridge to increase the visual preference when planning and designing bridges. Simulations with more detailed data about surroundings should be utilized practical design.

• 노동경제논집
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• 제26권3호
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• pp.49-75
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• 2003

본고는 생산현장에서의 인적자본 축적, 즉 근로자의 숙련형성에 영향을 주는 요인들을 실증적으로 찾아보고, 형성된 숙련이 생산성 향상에 기여하고 있는 것을 확인한다. 먼저 숙련형성의 유형은 '단순/견습근로자 < 단능근로자 < 다능근로자'의 직렬적 순서이다. 제품수요의 급변성과 비정상적인 상황 발생이라는 외부적 내부적 불확실성이 클수록 다능화가 활발하게 이루어지고 있으며, 선배 동료 근로자와의 상호학습, 근로자의 의사결정 참여, 직무 순환 등의 인적자원관리 관행들도 다능화를 촉진한다. 이러한 발견들로부터 생산 현장에서의 숙련형성은 다능화로 대표될 수 있다고 판단된다. 기업의 노동생산성 성장률을 기업의 성장률이라고 하면, 불확실성과 인적자원관리 관행들은 다능화를 통해서 기업의 성장에 영향을 준다. 구체적으로 기업의 다능화 비율이 0.1만큼 올라감에 따라 노동생산성 성장률이 0.019만큼 증가한다. 이것은 또한 다능화가 인적자원관리 관행들에 영향을 받아 형성되는 인적자본 축적의 한 결과라는 주장에 대한 근거가 될 수 있다.