• 전기학회논문지P
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• 제64권2호
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• pp.67-73
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• 2015

Distance relay is widely used for the protection of long transmission line. Most of distance relay used to calculate line impedance by measuring voltage and current using DFT. So if there is a computation error due to the influence of phasor by DC offset component, due to excessive vibration by measuring line impedance, overreach or underreach can be occurs, and then abnormal and non-operation of distance relay can be issue. It is very important to implement the robust distance relaying that is not affected by DC offset component. This paper describes an enhanced distance relaying based on the DC offset elimination filter to minimize the effects of DC offset on a long transmission line. The proposed DC offset elimination filter has not need any prior information. The phase angle delay of the proposed DC offset filter did not occurred and the gain error was not found. The enhanced distance relay uses fault current as well as residual current. The behavior of the proposed distance relaying using off-line simulation has been verified using data about several fault conditions generated by the ATP simulation software.

• 국제지역연구
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• 제14권3호
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• pp.109-130
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• 2010

서비스산업은 2005년 현재 세계 GDP의 2/3를 그리고 세계 무역의 20%를 차지하고 있어 그 중요성이 확대되고 있다. 또한 향후 정보통신기술 등 기술의 발전으로 서비스의 원거리간 교역(long-distance trade)은 확대될 것으로 예상된다. 하지만 서비스의 원거리간 교역에 대한 실증연구는 아직 활발하게 이루어지지 않고 있는 실정이다. 본 연구는 서비스의 원거리간 교역의 패턴을 분석하였다. 특히 다양한 특성을 가진 서비스들을 생산과 소비의 분리가능 여부에 따라 분류하여 서비스의 원거리간 교역의 패턴을 중력모형을 이용하여 분석하였다. 서비스의 원거리간 교역에 대한 신뢰할 만한 자료를 찾기가 어려워 본 연구는 지역산업연관표를 활용하여 분석하였다. 분석결과 생산과 소비가 분리되는 서비스가 생산과 소비가 분리되지 않는 서비스에 비해 원거리간 교역 가능성이 높은 것으로 분석되었다. 또한 지역의 총생산은 서비스의 원거리간 교역의 패턴에 있어 중요한 요인으로 분석되었다.

• 한국안광학회지
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• 제18권4호
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• pp.495-501
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• 2013

목적: 본 연구는 망원경과 바이프리즘(biprism)을 이용하여 골퍼로부터 깃대까지의 거리를 정확히 측정할 수 있는 골프 거리측정기를 개발하기 위한 것이다. 방법: 망원경내부에 이동 가능한 바이프리즘을 포함시켜 골프거리측정기를 제작하였으며. 20~200 m 거리에서 제작된 거리측정기의 정확도를 분석하였다. 결과: 바이프리즘의 위치에 따라 거리를 계산할 수 있는 방정식을 유도하였으며 개발된 골프거리측정기를 이용하여 성공적으로 거리를 측정할 수 있었다. 2 ${\Delta}$의 바이프리즘이 짧은 거리의 측정에서는 유용했지만 먼 거리의 측정에서는 정확도가 떨어지는 것으로 나타났으며 먼 거리의 측정에는 0.5 ${\Delta}$이 더 유용한 것으로 나타났다. 먼 거리를 측정하기 위하여 바이프리즘이 대물렌즈의 초점부근으로 접근할 때 상이 나빠지는 현상이 나타났으며, 이러한 약점을 보완하기 위하여 다층형 바이프리즘을 개발하였다. 결론: 바이프리즘을 이용하여 손떨림에 구애받지 않고 거리를 잘 측정할 수 있었으며 유도한 거리계산 방정식이 유용함을 확인하였다. 먼 거리를 측정하기 위하여 바이프리즘이 대물렌즈의 초점부근으로 접근했을 때 새로이 고안된 다층형 바이프리즘이 일반적인 바이프리즘보다 유용하다는 것을 확인하였다.

• 한국농공학회지
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• 제31권2호
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• pp.104-115
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• 1989

In an effort to clarify the wetted patterns of sandy loam soil under trickle irrigation conditions, the distance of wetted zone, infiltration capacity and soil wetted patterns, etc. were measured by gypsum block as soil moisture sensor located every 5 cm vertically and horizontaly in the soil bin under the such conditions as a). irrigation rates set to 2, 4, 6, 8 liters per hour b). total amount of water applied fixed to 14.62 liters per soil bin c) the hearing force of soil measured by plate penetrometer ranging from 1.04 to 1.22kg/cm$_2$ The results can be summarized as follows ; 1. The wetted distance in horizontal direction(H), the wetted distance in vertical direction(D), the horizontal infiltration capacity (iH) and the vertical infiltration capacity(in)could by explained as a function of time t. 2. The horizontal wetted distance (H) is explained by an exponetial function H= a$.$ t where b was found ranging from 021 to 026 under surface trickle irrigation, which was considered a lotlower than the classical value of 0.5 and these measurements were indifferent to the increasing irrigation rates. 3. As for the surface trickle irrigation where horizontal infiltration capacity(iH) is explained as iH = A $.$ t h, the coefficient A increases with respect to irrigation rates within the limits of 0.89~1.34. 4. In terms of surface trickle irrigation of the ratio of Dm Which is maximum vertical wetted distance to Hm, which is maximum horizontal wetted distance, found to be within range of 1.0 to 1.21. It was also noted that the value of Dm decreses when irrigation rates increases while the value of Hm changes the opposite direction. 5. The optimum location of sensors from emitter for surface trickle irrigation should he inside of hemisphere whose lateral radius is 28~30cm long and vertical radius is 10~12cm long. The distance between emitters should be within 60cm long. 6. In the study of vertical wetted distance( D) where D= a $.$ tb, the exponential coefficient b ranged from 0.61 to 0.75 in surface trickle irrigation, and from 0A9 to 0.68 for subsurface trickle irrigation. These measurements showed an increasing tendency to with respect to irrigation rates. 7. In case of vertical infiltration capacity( in), where iD= A $.$ t 1-h, the coefficient A for surface trickle irrigation found to be within range of 0.16 to 0.19 and did not show any relationships with varying degree of irrigation rates. However, the coefficient was varying from 0.09 to 0.22 and showed a tendency to increase vis-a-vis irrigation rates for subsurface trickle irrigation, in contrast. 8. In the observation of subsurface trickle irrigation, it was found that Dm/Hm ratio was within 1.52 to 1.91 and showed a decreasing tendency with respect to increasing rates of irrigation. 9. The location of sensors for subsurface trickle irrigation follows same pattern as above, with vertical distance from emitter being 10~17cm long and horizontal 22~25cm long. The location of emitter should be 50 cm. 10.The relationship between VS which is the volume of wetted soil and Q which is the total amount of water when soil is reached field capacity could be explained as VS= 2.914Q0.91and the irrigation rates showed no impacts on the above relationship.

• 한국의류학회지
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• 제33권2호
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• pp.266-275
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• 2009

Variations of individual hip shapes are a major obstacle in pattern making for fitness. The drafting method is used for pattern making in today's apparel industry. Whilst catering to a limited number of information such as waist and hip sizes, this method does not cater to variations in hip shape. This paper describes the analysis of hip shapes using 3D body model and tries to make sure the relationship between hip shape and pattern by calculating hip angle and dart amount. We achieved results in analyzing various hip shapes by extracting hip angle. Moreover, various hip shapes can be divided into three types(A, B and C) by the hip angle value($K_{sh}-K_{wsh}$). When we use computerized draping method to make a personalized pattern for a tigth skirt, we easily create complex dart lines automatically. Therefore we achieve the result of individual dart amount such as distance between dart lines and dart areas. C type of hip shape had short dart length, long distance between dart lines and a large amount of dart area. On the other hand, A type had long dart length, short distance between dart lines and small amount of dart area. B type had long length and long distance between dart lines and large amount of dart area. In traditional pattern making, distance between dart lines is usually proportional to amount of dart area because of similarity in dart line shape. In our pattern, there is no proportional relationship between dart line distance and dart area. This means that variations in hip shapes result in a wide variety of dart line curvature resulting in a wide range of dart area. By ensuring an accurate relationship between hip shape and pattern, it is possible to make patterns which result in clothing that not only fits well, but also exhibits other desirable properties.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.291-291
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• 2002

DGPS(Differential Global Positioning System) and RTK(RealTime Kinematic) is in one of today's most widely used surveying techniques. But It's use is restricted by the distance between reference station and rover station and it is difficult to process data in realtime by it's own orgnizational limitation in precise measurement of positioning. To meet these new demands, In This paper, new DGPS and RTK correction data services through Internet and PSTN(Public Switched Telephony Network) have been proposed. For this purpose, we implemented performance a DGPS and RTK error correction data transmission system for long-distance using the internet and PSTN network which allows a mobile user to increase the distance at which the rover receiver is located from the reference in realtime. and we analyzed and compared DGPS and RTK performance by experiments through the Internet and PSTN network with the distance and the time.

• 천문학논총
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• 제30권2호
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• pp.371-374
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• 2015

Classical Cepheids (hereafter Cepheids) belong to a class of important variable stars that can be used to determine distances to nearby galaxies via the famous period-luminosity (PL) relations, i.e. the Leavitt Law. In turn, these distances can then be used to calibrate a host of secondary distance indicators located well within the Hubble flow, and ultimately determine the Hubble constant in a manner independent of the Cosmic Microwave Background (CMB) measurements. Some recent progress in determining the Hubble constant to within ~ 3% level via the Cepheid-based distance scale ladder (the SH0ES and the Carnegie Hubble Program) were first summarized in this Proceeding, followed by a brief discussion on the prospect of using ultra-long period Cepheids (ULPC) in future distance scale work. ULPC are those Cepheids with periods longer than 80 days, which seem to follow a different PL relation than their shorter period Cepheids. It has been suggested that ULPC can be used to determine the Hubble constant in "one-step". However, based on the two ULPCs found in M31, it was found that the large dispersion in derived distance moduli leads to a less accurate distance modulus to M31 compared to the classical Cepheids. This finding might raise an alert regarding the use of ULPCs in future distance scale work.

• Geomechanics and Engineering
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• 제37권4호
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• pp.395-418
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• 2024

The epicentral region of earthquakes is typically where liquefaction-related damage takes place. To determine the maximum distance, such as maximum epicentral distance (R_e), maximum fault distance (R_f), or maximum hypocentral distance (R_h), at which an earthquake can inflict damage, given its magnitude, this study, using a recently updated global liquefaction database, multiple ML models are built to predict the limiting distances (R_e, R_f, or R_h) required for an earthquake of a given magnitude to cause damage. Four machine learning models LSTM (Long Short-Term Memory), BiLSTM (Bidirectional Long Short-Term Memory), CNN (Convolutional Neural Network), and XGB (Extreme Gradient Boosting) are developed using the Python programming language. All four proposed ML models performed better than empirical models for limiting distance assessment. Among these models, the XGB model outperformed all the models. In order to determine how well the suggested models can predict limiting distances, a number of statistical parameters have been studied. To compare the accuracy of the proposed models, rank analysis, error matrix, and Taylor diagram have been developed. The ML models proposed in this paper are more robust than other current models and may be used to assess the minimal energy of a liquefaction disaster caused by an earthquake or to estimate the maximum distance of a liquefied site provided an earthquake in rapid disaster mapping.

• 한국환경과학회지
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• 제25권6호
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• pp.799-815
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• 2016

In this study, according to the reference setting based on the runoff video of 9:00 where the highest water level of 3.94 m has been recorded during the runoff of Cheon-mi Stream in Jeju Island by the attack of Typhoon no. 16 Sanba on September $17^{th}$, 2012, the error rate of long-distance and short-distance velocimetry and real-distance change rate by input error have been calculated and the input range value of reference point by stream has been suggested. In the reference setting process, if a long-distance reference point input error occurs, the real-distance change rate of 0.35 m in the x-axis direction and 1.35 m in y-axis direction is incurred by the subtle input error of 2~11 pixels, and if a short-distance reference point input error occurs, the real-distance change rate of 0.02 m in the x-axis direction and 0.81 m in y-axis direction is incurred by the subtle input error of 1~11 pixels. According to the long-distance reference point setting variable, the velocity error rate showed the range of fluctuation of at least 14.36% to at most 76.06%, and when calculating flux, it showed a great range of fluctuation of at least 20.48% to at most 78.81%.

• 한국언어정보학회지:언어와정보
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• 제15권1호
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• pp.63-78
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• 2011

This study investigates the binding behavior of the Korean anaphor 'caki', which has been regarded thus far as a long-distance anaphor (LDA). Given that even local anaphors can be bound long-distance when they function as exempt anaphors in certain languages (Pollard and Sag 1992; Kim and Yoon 2009a, b), I investigated the binding behavior of LD-bound 'caki', in order to determine whether LD-bound 'caki' differs from LD-bound 'caki-casin' in the same contexts. In the experiment, subjects were required to rate the grammaticality of Korean sentences representing various types of LD binding of 'caki' and to determine whether the sloppy or the strict reading was more prominent in elliptical VPs containing the anaphor. The results are discussed with respect to the typology of LDAs proposed by Cole, Hermon and Huang (2001).