• Korean Architects
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• no.12 s.332
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• pp.44-50
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• 1996

• Korean Architects
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• no.10 s.330
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• pp.64-69
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• 1996

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.361-368
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• 2013

As one way to describe the behavior of a vibrating string, analogies to a transmission line have been made based on the fact that they have oppositely travelling waves on each of them. In such analogies, a rigid end to the string has been represented as an open circuit, and the displacement of the string as the current on the transmission line. However it turns out that the rigid end corresponds to a short circuit, the displacement to the voltage by the theory of the transmission line, and it is confirmed by experiments with circuit simulations. Based on these discoveries, a transmission line based plucked string model comprising a transmission line, two piecewise linear current sources, and switches is proposed. The proposed model is validated by showing that the voltage at the arbitrarily chosen location, and the voltage calculated over an infinitesimal portion at the end of the transmission line are consistent with the displacement at the corresponding location and the force on the rigid end of the string from the well known difference form of a wave equation governing the behavior of the string with its fundamental frequency tuned to that for the proposed model, respectively. Moreover, the applicability of the proposed model to modeling string and wind instruments is presented.

• Journal of National Security and Military Science
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• s.13
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• pp.137-658
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• 2016

1. Movement of the leaders of the Silla army The leaders of the Silla army traveled from Gyeongju(경주) to Icheon (이천), Deokjeokdo(덕적도) Island, and Hwangsanwon(황산원) during the period of the Against Baekje(백제) War that began in 660. Movement route between Gyeongju and Icheon : Gyeongju(경주)-Daegu(대구)-Gumi(구미)-Gimcheon(김천)-Chupungryeong(추풍령)-Geumdol Fortress(금돌성)-Boeun(보은)-Jincheon(진천)-Juksan(죽산)-Bubal-eup(부발읍) Movement route between Bubal-eup and Deokjeokdo Island : Bubal-eup(부발읍)-Ipo(이포) Ferry-Haengju(행주) Ferry-Palmido (팔미도) Island-Seonjaedo(선재도) Island-Yeongheungdo(영흥도) Island-Pido(피도) Island-Soyado(소야도) Island-Deokjeokdo(덕적도) Island Movement route between Deokjeokdo Island and Hwangsan: Deokjeokdo(덕적도) Island-Danghangpo(당항포)-Jincheon(진천)-Boeun (보은)-Okcheon(옥천)-Geumsan(금산)-Tanhyeon(탄현)-Hwangsan (황산)-Ganggyeong(강경)-Buyeo(부여) 2. Movement of the combat units of the Silla army Jincheon area : 4,325 persons of the Geupdang unit(急幢) and 611 persons of the Kaegeumdang unit(罽衿幢) were deployed. These units moved from Jincheon to Cheongju, Yeongi, and Gongju, and contained Ungjin Fortress(熊津城) (6,650 Baekje troops). Boeun area : 4,763 persons of the Daedang(大唐) unit, 3,548 persons of the Hajujeong unit(下州停), 3,017 persons of the Namcheonjeong unit(南川停), and 4,500 persons of the Saseoldang unit(四設幢) were deployed. These units moved from Boeun(보은) to Okcheon(옥천), Geumsan(금산), Tanhyeon,(탄현) and Hwangsan(황산). Geumdol Fortress area : 3,753 persons of the Sangjujeong unit(上州停), 5,762 persons of the Seodang unit(誓幢), 3,753 persons of the Guidang unit(貴幢), and 5,562 persons of the Nangdang uni(郎幢)t were deployed. These units moved from Geumdol Fortress to Hwanggan(황간), Yeongdong(영동), Geumsan(금산), Tanhyeon(탄현), and Hwangsan(황산). Jirye area: 3,017 persons of the Eumrihwajeong unit(音里火停) and 3,017 persons of the Ehwahyejeong unit(伊火兮停) were deployed. These units moved from Jirye(지례) to Juchiryeong(走峙嶺), Mupung (무풍), Muju-eup(무주읍), and Bunam-myeon(부남면) in Muju-gun. Goryeong area: 3,017 persons of the Samryanghwajeong unit(三良火停) and 3,017 persons of the Sosamjeong unit(召參停) were deployed. These units moved from Goryeong(고령) to Geochang(거창), Hamyang(함양), Namwon(남원), Sunchang(순창), and Jeongeup(정읍). 3. Movement of the Tang army Dangjin area(당진 방면) : 1,000 persons were deployed. These units moved from Dangjin(당진) to Myeoncheon(면천), Yesan(예산), and Imjon Fortress(임존성). Garijeo area(가리저 방면) : 1,000 persons were deployed in the Garijeo(加里渚) area. These units moved from Garijeo(가리저) to Myeoncheon(면천), Yesan(예산), and Imjon Fortress(임존성). Geumganggu area(금강구 방면) : 000 persons were deployed. These units moved from Geumganggu(금강구) to Ganggyeong(강경) and Sabi Fortress(사비성). 4. Baekje military deployment Total troops of the Baekje army : There were 60 thousand Baekje troops according to the Old Book of Tang(舊唐書). Troop deployment by the Baekje army: 62,230 persons were deployed in 15 regions: 1,000 in Dangjin(당진), 1,000 in Garijeo(가리저), 6,120 in Imjon Fortress(임존성), 1,120 in Namjam Fortress(남잠성), 1,350 in Dooryangyun Fortress(두량윤성), 870 in Wangheungsajam Fortress(왕흥사잠성), 6,650 in Ungjin Fortress(웅진성), 1,120 in Jinhyeon Fortress(진현성), 1,000 in Dooshiwonak(두시원악), 1,000 in Irye Fortress(이례성), 5,000 in Gosaburi Fortress(고사부리성), 5,000 in Gujiha Fortress(구지하성), 3,000 plus 3,000 in Gibeolpo and Yangan(기벌포 양안), 5,000 in Deukan Fortress(득안성), and 20,000 in Sabi Fortress(사비성).

• Journal of the Korean institute of surface engineering
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• v.30 no.1
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• pp.23-32
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• 1997

The electrolytic boronizing on carbon steels in the mixture of $Na_2B_4O_7$ and NaCl was conducted at 750~$950^{\circ}C$ for 1~6 hours under 0.5A/$\textrm{cm}^2$ current density. The micorostructrure and microheredness of boronized layer was also studien. The effect of the additive such as $CaCl_2$ or NaOH on the formation of boronized layer was also investigated. The boronized layer were composed of two sublayers, i.e., FeB and $Fe_2B$ , which have tooth structure. the average layer thinknesses of the low carbon steel and SM45C boronized at $900^{\circ}C$ for 4hours were 153 and 138 $\mu\textrm{m}$, respectively. The thickness of the twosublayers was significantly increased with increasing boronizing temperature. To obtain a single $Fe_2B$ layer without FeB sublayer, the boronized materials ware homegenized at $950^{\circ}C$ for 4 hours. It was fount that the single layer with a microhardness Hv$\thickapprox$ 1120 -1250 was formed. The calculated activation energies for formation of boronized layer on the low carbon steel and SM45C were 18.7 and 12.6 Kcal/mol, respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.134-142
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• 2012

This paper presents a study of system identification on the tilt response of the L-type retaining wall located at Tanhyun 11th ACE Apartment, Ilsan in order to understand mechanism how the structure behaves in operational conditions and to provide a reference tilt values for assessing structural abnormality. The retaining wall was extraordinarily tall (14m) in urban area so the long-term monitoring system had been installed with 3 tilts-meters and 9 temperature sensors operational from Oct 2004 upto Nov 2007. By using 5-months continuous data in which all the 12 channels were up and running, the two prediction models, 1) the linear model, and 2) the state-space equation (SSE) model, have been identified by finding the best fitness model among all possible 511 combinations of input temperatures out of the 9 temperatures. The linear model which was simple in the model structure achieved the validation fittness of 68% due to the fact that the static model wasn't able to represent thermal dynamics. The SSE model achieved the validation fitness of 90% which was quite accurate considering various unexpected noises happening in field measurements.