• Structural Engineering and Mechanics
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• 제41권2호
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• pp.285-297
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• 2012

An inverse approach is presented for calculating the flexibility coefficient of open-side cracks in the cross sectional of beams. The cracked cross section is treated as a massless rotational spring which connects two segments of the beam. Based on the Euler-Bernoulli beam theory, the differential equation governing the forced vibration of each segment of the beam is written. By using a mathematical manipulation the time dependent differential equations are transformed into the static substitutes. The crack characteristics are then introduced to the solution of the differential equations via the boundary conditions. By having the time history of transverse response of an arbitrary location along the beam, the flexibility coefficient of crack is calculated. The method is applied for some cracked beams with solid rectangular cross sections and the results obtained are compared with the available data in literature. The comparison indicates that the predictions of the proposed method are in good agreement with the reported data. The procedure is quite general so as to it can be applicable for both single-side crack and double-side crack analogously. Hence, it is also applied for some test beams with double-side cracks.

• 한국전자파학회논문지
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• 제14권10호
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• pp.1079-1088
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• 2003

본 논문에서는 도선상의 결함 감지 및 추정 방법인 고분해능 시간-주파수 반사측정기법(time-frequency domain reflectometry)을 제안한다. 이 방법은 관측된 신호를 시간과 주파수 영역에서 동시에 분석 가능한 시간-주파수 상호 상관 관계(time-frequency cross correlation) 특성을 채택하였다. 제안된 방법인 TFDR의 정확도는 고주파용 coaxial cable을 가지고 실험을 통하여 기존의 방식들과 비교 검증하였다. 제안된 알고리즘의 다양한 결함들에 대한 감지 및 추정 결과, 기존의 방법에 비해 월등하다는 것을 명백히 나타내었다.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.269-283
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• 2022

In this paper, a particular type of all-steel HSS brace members with a locally reduced cross-sectional area was experimentally and numerically investigated. The brace member was strengthened against local buckling with inner and outer boxes in the reduced area. Four single-span braced frames were tested under cyclic lateral loadings. Specimens included a simple steel frame with a conventional box-shaped brace and three other all-steel reduced section buckling-restrained braces. After conducting the experimental program, numerical models of the proposed brace were developed and verified with experimental results. Then the length of the proposed fuse was increased and its effect on the cyclic behavior of the brace was investigated numerically. Eventually, the brace was detailed with a fuse-to-brace length of 30%, as well as the cross-sectional area of the fuse-to-brace of 30%, and the cyclic behavior of the system was studied numerically. The study showed that the proposed brace is stable up to a 2% drift ratio, and the plastic cumulative deformation requirement of AISC (2016) is easily achieved. The proposed brace has sufficient ductility and stability and is lighter, as well as easier to be fabricated, compared to the conventional mortar-filled BRB and all-steel BRB.

• 무역학회지
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• 제46권6호
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• pp.239-255
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• 2021

To review the theoretical background of regulatory approaches to cross-border transfer of personal data, this paper divides major digital trade participating countries into four types according to the OECD - non-regulatory, post-intervention, pre-supervision, and national control. It then analyzes the US, Japan, the EU, and China respectively that belong to each type. South Korea, which is currently about to pass the amendment by the National Assembly, has identified that it is in the middle of post-intervention and pre-supervision, and needs to evolve into pre-supervision norms like the EU while it has to participate more actively in the process of establishing international digital trade rules. Korea first needs to sign digital trade agreements and promote mutual certification projects more actively from the standpoint of a medium-sized open country with growing digital companies and digitally-open consumers. Second, the government should fully consider the interests of not only companies but also various trade stakeholders including domestic consumers, when drafting and implementing trade policies. To this end, 'a single window approach' is needed not only at the Ministry of Trade, Industry, and Energy, but also at the level of the entire government which require an integrated form of digital trade policy governance.

• 가정과삶의질연구
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• 제32권2호
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• pp.1-11
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• 2014

This study investigated the characteristics of housing considerations of college students from post graduation to pre marriage. The data came from the survey with 267 college students in Ulsan and Daegu from November 26 through December 14, 2012 and were analyzed with descriptive statistics, cross-tabulation analysis with chi-squared test, and logistic regression analysis. Over half of the respondents desired to separate from parents for the adulthood and about forty-three percent of them wanted to live alone. Among the housing characteristics, location, utilities, housing type and facility features were important for the respondents desiring to live the single life, and specifically, apartment and efficiency with $33-66m^2$, low monthly rents, floor plan with bedroom, kitchen and bathroom, and good public transportations were the most and primarily preferred features of housing for their future housing consideration. The variables influencing future housing preferences for the respondents were the number of roommate and preferred housing type.

• 한국육종학회지
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• 제41권2호
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• pp.173-176
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• 2009

A new spray chrysanthemum cultivar 'Pure Angel' was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea in 2007. The cross was made in 2004 between 'Innocence', a breeding cultivar of NIHHS, and 'Baeksokuk', a spray cultivar with white petals. Trials were conducted from 2005 to 2007 for the evaluation and selection of this cultivar, including shade cultures in summer and retarding cultures in autumn. The natural flowering time of 'Pure Angel' is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pure white petals and a green flower center. It shows long vase life and resistance to white rust. The diameter of flower is 52.5 mm. The numbers of flowers per stem and petals per flower are 12 and 22.5, respectively. Days to flowering under the short day treatment is about 52 days in spring seasons.

• 한국육종학회지
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• 제40권4호
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• pp.439-442
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• 2008

A new spray chrysanthemum cultivar, 'Cherry Blossom' was released by National Horticultural Research Institute (NHRI), Rural Development Administration (RDA), Korea in 2007. A cross was made in 2002 between 'Relance', a spray cultivar with red petals and resistant to white rust and 'Yeonja', a spray cultivar with pink petals. Trials were conducted from 2005 to 2007 for the evaluation and selection of this cultivar, including shading culture in summer and retarding culture in autumn. The natural flowering time of "Cherry Blossom" is late October, but year-round flowering is possible by shading and lighting treatment. This cultivar is single type flowers with dark pink petals and green flower center and resistant to white rust. It is very stable color of petals when the variety is cultivated under high temperature conditions in summer season. The diameter of flower is 55.0 mm. The number of flowers per stem is 10.5 and the number of petals per flower is 24.0. The days to flowering under the short day treatment is about 45 in spring season.

• 한국육종학회지
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• 제42권6호
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• pp.595-599
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• 2010

A new spray chrysanthemum cultivar 'Prima Donna' was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), in 2008. The cross was made between 'Plano' and 'Yeonja' in 2005. Trials were conducted from 2006 to 2008 for the evaluation and selection of this cultivar, including shading cultures in summer and retarding cultures in spring. The natural flowering time of 'Prima Donna' is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pink petals, green center and good inflorescence. The growth of plant is very vigorous. The diameter of flower is 7.0cm. The number of flowers per stem and petals per flower are 13 and 42, respectively. Days to flowering under the short day treatment is about 59 and its vase life is 26.1 days in autumn season.

• 한국육종학회지
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• 제41권2호
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• pp.141-144
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• 2009

A new spray chrysanthemum 'Pink Berry' was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea in 2007. A cross was made in 2004 between 'Lineker Salmon', a spray cultivar with salmon petals, and 'Baeksokuk', a spray cultivar with white petals. Trials were conducted from 2005 to 2007 for evaluation and selection of this cultivar, including shade cultivation in summer and retarding cultivation in autumn. The natural flowering time of 'Pink Berry' is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pink petals and a green flower center. It shows long vase life of 22 days and resistance to white rust. The diameter of flower is 52.0 mm. The numbers of flowers per stem and petals per flower are 15.5 and 29.5, respectively. Days to flowering under the short day treatment is about 56 in autumn seasons.

• 대한치과보철학회지
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• 제35권2호
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• pp.373-384
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• 1997

In this study, 4 types of dowel pin were used to fabricate removable dies using the Pindex system. The comparison of interabutment distances between before and after sawing were conducted in each type of dowel pin, and the horizontal discrepancies in the interabutment distance according to the abutment location and the type of dowel pin were comparatively analyzed. Abutments LM(left molar), LP(left premolar), A(anterior), RP(right premolar), and RM (right molar) were used for measurement. The interabutment distances were measured between each abutment : LM-LP, LM-A, LM-RP, and LM-RM. The slide scanned image of each model was magnified on the computer screen and the measurements were conducted using the meeting point of the cross on the occlusal surface of each abutment. The results were as follows : 1. In the comparison of interabutment distances between before and after sawing in each type of dowel pin, there was no significant difference in World dowel pin(double), Bi-pin(double), Maxcel dowel pin(single). In the World dowel pin(single) there was no significant difference between LM-LPs, but in the other measurements (LM-As, LM-RPs, and LM-RMs) there was significant difference between before and after sawing(p<0.05). 2. In comparison of horizontal discrepancies of the measurement according to the abutment location, there was significant difference between measurement LM-LP($0.27{\pm}0.19mm$) and the others : LM-A($0.46{\pm}0.20mm$), LM-RP($0.38{\pm}0.25mm$), LM-RM($0.45{\pm}0.22mm$) (p<0.05). 3. In comparison of horizontal discrepancies of the measurement according to the type of dowel, there was no significant difference between each dowel. As a result when fabricating a removable die using the previously mentioned 4 types of dowel pins, it is thought that the horizontal discrepancy increased in proportion to the interabutment span length and does not depend on the type of dowel pin.