• ETRI Journal
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• 제34권6호
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• pp.858-868
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• 2012

In this paper, stochastic models for the cross-correlation of multiple channels are established based on measurement data collected using a wideband multiple-input multiple-output relay Band Exploration and Channel Sounder system at 3.7 GHz. We propose models for the cross-correlation characteristics of large-scale parameters (LSPs) between two links, that is, the base station and mobile station (MS) link and the relay station and MS link. The LSPs include shadow fading, Rician K-factor, delay spread, angle spread of arrival, and angle spread of departure. Furthermore, models are established for the cross-correlation of the small-scale fading in the impulse responses of two links. The statistics of these model parameters are investigated as functions of geometrical features of the multilink. They are extracted from a large amount of cross-correlation observations, which are obtained in three measurement sites along more than one hundred measurement routes. These models can be used together with the standard single-link channel models for the generation of correlated components, for example, path clusters, in two separate channels.

• 한국정밀공학회지
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• 제4권4호
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• pp.36-42
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• 1987

Very accurate calibration is needed to index tables which are necessary for precision angle measurement. The repeatability of index table is less than 0.2 second, so that attentions should be paid to choosing devices to be used in the calibration of index tables. The auto- collimators have been used in the calibration of index tables, but the repeatability of auto- collimators is bad compared with that of index table. In place of autocollimators, we described a method which uses electric comparators which are possessed by most precision measurement laboratories. Electric comparators are set to measure small angle displacement without interrupting the rotation of index tables and the signals of two electric comparators are added to remove the run-out errors of the shafts of index tables. Two index tables have been calibrated simulataneously by this method and the measurement data have been analyzed by the least squares method. We compare the calibration results with those of methods using autocollimator and auto- matic autocollimator and are able to know that the data of electric comparator method lie between the data of autocollimator methods. The repeatability of measurement is less than 0.02 second. The electric comparator method is economical and capable of reducing the uncertainty of the measurement.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1619-1621
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• 2007

Novel optical measurement systems and improved cell configurations for measuring of azimuthal anchoring energies were developed. The difference between the mechanical rubbing direction and the optical easy axis that caused errors in the previous azimuthal anchoring energy measurement was compensated. In addition, the measurement accuracy of the twist angle and therefore the azimuthal anchoring energy was greatly enhanced. As a result, we were able to obtain valid azimuthal anchoring energy values for different alignment layers.

• Journal of Electrical Engineering and information Science
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• 제3권1호
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• pp.80-85
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• 1998

A theoretical calculation and an optical measurement method of normal-incidence absorption are proposed. By using a waveguide structure, optical interference and the problem of low level signal can be avoided in the measurement of normal-incidence absorption. The oscillator strength of intersubband absorption for a waveguide structure is calculated in Si(001), Si(110), and Ge(001) quantum wells. The polarization angle dependence of the measured and the calculated absorption strength can be obtained with the same waveguide structure, and be compared after normalization. The normal-incidence absorption in Si(110) and Ge(001) quantum wells is shown theoretically, and can be observed in the optical measurement using waveguide structures at the polarization angle of 90$^{\circ}$.

• 대한임베디드공학회논문지
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• 제12권4호
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• pp.223-229
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• 2017

An angle error is a factor obstructing to track accurate position in tracking radars. And the noise incurring the angle error can be divided as follows; thermal noise and glint. In general, Extended Kalman filter used in tracking radars is designed with considering thermal noise only. The Extended Klaman filter uses a fixed measurement error covariance when updating an estimate state by using ahead state and measurement. But, a noise power varies according to the range. Therefore we purposes the adaptive Kalman filter which changes the measurement noise covariance according to the range. In this paper, we compare the performance of the Extended Kalman filter and the proposed adaptive Kalman filter by considering KSLV-I (Korean Satellite Launch Vehicles).

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.629-634
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• 2002

Demands for the automatic measurement on angle and depth of equipment were arisen for the better construction in deep mixing method and grouting method. Civil, geotechnical, electronic, and communication experts worked together for the development of automatic measuring devices using wire and wireless transmitting-receiving set. The results on the development of automatic devices in an industrial installation will be presented.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.531-533
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• 2007

A new method is developed for the measurement of twist angles of LC molecules in an LC panel with angular resolution of 0.01degree, which allows measurement of LC panels with small twist angles. The method is based on the analysis of the change in polarization state of a light beam as it passes through the LC panel in test is rotated in-plane. Compared to other traditional method, including the analysis of transmittance change, our method is more sensitive and more precise. This method allows accurate determination of anchoring energy and close analysis of the rubbing process in the fabrication of IPS mode LC panels.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.819-820
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• 2007

• 대한족부족관절학회지
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• 제13권1호
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• pp.1-6
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• 2009

Purpose: To study the reliability of intra- and interobserver reliability in angular measurement of hallux valgus deformity by assessing hallux valgus angle (HVA) and the 1st to 2nd intermetatarsal angle (1-2 IMA) through using computerized system. Materials and Methods: 20 cases of moderate to severe hallux valgus patients were included in this study. With the standing anteroposterior view of foot, the HVA and 1-2 IMA were calculated by computerized measurement system of Infinity cooperation, called ${\pi}$-view, with its software tools. Using the statistical software program, SPSS (version 12th), we interpreted the results which were measured by two independent observers. Results: In the intraobserver measurement, the HVA of observer A showed reliability ($32.5^{\circ}{\pm}6.9$ and $33.1^{\circ}{\pm}6.8$)(p<0.05). 1-2 IMA in observer A was not regarded as reliable ($16.9^{\circ}{\pm}2.8$ and $17.1^{\circ}{\pm}2.8$)(p>0.05). In the results of observer B, HVAs were measured as $35.7^{\circ}{\pm}7.6$ and $36.2^{\circ}{\pm}7.7$, and were not reliable (p>0.05). 1-2 IMA in observer B was not reliable as well ($17.0^{\circ}{\pm}0.8$ and $20.8^{\circ}{\pm}1.5$)(p>0.05). In the interobservers' measurements, the first and the second results of HVA were $3.2^{\circ}{\pm}3.6$ and $3.1^{\circ}{\pm}3.1$, reliable within the 95% confidence interval (p<0.05). 1-2 IMAs were $0.1^{\circ}{\pm}1.9$ and $3.73^{\circ}{\pm}1.3$, which were not reliable (p>0.05). Conclusion: In the angular measurement of the hallux valgus by computerized system, the HVA and 1-2 IMA showed less error range in the interobserver's results, compared with the previous studies about the manual measurement. However, our results failed to show the statistical reliability of intra- and interobserver's measuring. Therefore, even the computerized angular measurements in the severity of hallux valgus require development of the measuring methods and software tools.

• 대한치과교정학회지
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• 제33권4호
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• pp.293-305
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• 2003

인두는 호흡과 연하를 수행하는 기관의 일부를 구성하며 이의 기능 및 형태는 두개악안면구조의 형태와 밀접한 관련성을 가지는 것으로 알려져 있다. 본 연구의 목적은 정상과 개방교합성 골격형태에서 인두와 연구개, 혀 그리고 설골을 포함하는 기도크기를 비교하고 또한 각 군에서 연령에 따른 차이를 평가하는 것이다. 본 연구의 대상은 51명의 정상골격군(정상군)과 52명의 개방교합성 골격군(개방골격군)으로 구성되고 각각은 연령에 따라 아동군(9-12세)과 성인군(18세 이상)으로 나누었다. 측모두부 규격 방사선 사진이 촬영하였고 안면 골격과 인두, 연구개, 혀 그리고 설골의 거리, 각, 비율을 계측하고 통계적으로 분석하여 다음과 같은 결론을 얻었다. 1. 정상군과 개방골격군 모두 SN-Mn angle, FMA와 Pal-Mn angle은 아동군에서 성인군보다 컸으며, facial height ratio(FHR)는 성인군보다 아동군에서 작았다. Occl-Mn angle은 개방골격군과 정상군에 따라서는 유의한 차이가 있었으나 아동군과 성인군 사이에 유의한 차이는 관찰되지 않았다. 2. SN-Mn angle, FMA, Palatal-Mn angle, lower anterior facial height(LAFH), FHR 등은 정상군보다 개방골격군에서 기도크기와 높은 상관관계를 보였고 성인군보다 아동군에서 높은 상관관계를 보였다. 개방골격 아동에서 SN-Mn angle, FMA, Palatal-Mn angle은 비인두의 골격적 전후방 크기와 비인두강의 전후방 깊이와 높은 역상관관계를 보이나 이는 성인이 되면 사라졌다. LAFH는 기도의 수직적인 계측치와 높은 순상관관계를 보였다. 3. 수직적 골격 형태에 따라서 기도 크기에서는 유의한 차이를 보이지 않았다. 4. 인두의 연조직 두께는 성인군에서 아동군보다 작았으며 비인두강의 깊이는 성인군에서 더 큰 값을 보였고, 아동군과 성인군에서의 구인두강의 깊이는 유의한 차이가 없었다. 5. 설골의 전후방적인 위치는 아동군과 성인군에서 차이를 보이지 않았으나 수직적으로는 성인군에서 아동군보다 더 하방에 위치하였다.