• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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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.

• International Area Studies Review
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• v.14 no.3
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• pp.109-130
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• 2010

The service sector comprises two thirds of world GDP in 2005 and takes 20% of the world trade. As the technologies such as telecommunication technologies advance, the long-distance trades in services is expected to increase. But there are few empirical research on the flows of services between regions. This paper studies the pattern of flows of long-distance trades in services across the regions. Since it is very hard to collect reliable data on long-distance trade in services, we collect data from regional input-output tables of Korea. The results shows that the hard service which can be consumed spatially separated from production tends to have more long-distance trade than the soft service which is consumed simultaneously with production. It also shows that regional gross domestic production is important factor for the pattern of trades in services.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.495-501
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• 2013

Purpose: This study was to develop golf range finder which could measure exact distance from golfer to flag by using telescope and biprism. Methods: Golf range finder was made that included telescope and biprism which could move in the telescope, and an accuracy of the range finder was analyzed in distance range 20~200 m. Results: An equation was made for measuring distance which was related at position of biprism, and we could measure distance successfully by using developed golf range finder. Biprism of 2 ${\Delta}$ was useful to measure in short distance but it had bad accuracy in long distance, and 0.5 ${\Delta}$ was more useful in long distance. Image got worse when the biprism approch to focal point of objective lens for measurement in long distance, so we developed multi-layer biprism to prevent the weak point. Conclusions: Image stabilization by biprism for measuring distance was confirmed. Even if hand was moving, the distance could be measured well by using biprism, and we could find that the induced equation for distance measurement was useful. We found that multi-layer biprism, which is was new developed, was more useful than general biprism when the biprism approched to focal point of objective lens for measurement in long distance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.2
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.2
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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.

• Proceedings of the KSRS Conference
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• 2002.10a
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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.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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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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• v.37 no.4
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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.

• Journal of Environmental Science International
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• v.25 no.6
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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%.

• Language and Information
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• v.15 no.1
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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).