• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.1
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• pp.23-29
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• 2011

This study investigates the axial behavior of CFRP strengthened circular CFT columns and proposes the design formula of CFRP strengthened circular CFT columns. 10 specimens were prepared and axial loading test were conducted to investigate the retrofitting effects of CFRP composites on CFT columns. The main parameters are the number of FRP sheets and D/t ratio. Test results showed that the CFRP retrofitting enhanced the load bearing capacity of the circular CFT columns. Finally, A ACI 440 code applied ultimate axial strength formula is proposed to predict the ultimate strength of CFRP strengthened circular CFT columns. The proposed formula are good agreement with the test results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.12
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• pp.1233-1238
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• 2003

In this paper, radially corrugated circular-type microstrip patch antenna was devised and manufactured for GPS (center frequency: 1.575 GHz). Radially corrugated circular-type microstrip patch antenna having radiational corrugation-patch contributed to add size reduction ratio by lowering the resonant frequency because the edge current also has the extended and perpendicular path. As a result, radially corrugated circular-type microstrip patch antenna has 28 % area reduction than planer circular-type patch antenna for linear polarization and 27.7 % area reduction than planer circular-type patch antenna for circular polarization. Radially corrugated circular-type microstrip patch antenna is suitable for miniaturized receive antenna for GPS which has the characteristic of gain 2.1 dBd, axiai ratio 1.3 dB, 2 dB axial bandwidth 15 MHz(0.9 %).

• Journal of the Korea Society of Computer and Information
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• v.27 no.6
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• pp.95-107
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• 2022

This study attempted to develop a bodice prototype suitable for the 20's obese male's trunk with a BMI of 25kg/m² or more, which is distinguished from the standard body type. Through this, it was intended to provide data to help the development of clothing for obese males. Patterns such as front bodice shoulder line and front sagging were modified through primary appearance and garment pressure evaluation. Through the second evaluation, corrections such as back armhole, back waistline, and front sagging were performed. Through the third evaluation, the final pattern drafting method was developed by removing the front sagging added through the second evaluation. In the case of obese male body types in their 20s, a drafting method distinguished from the standard body type was required in the method of setting the front and back waist lines, back armhole darts, and front shoulder lines due to protruding and posture of the abdomen. This study was meaningful in that it presented a bodice prototype drafting method suitable for the 20s obese males. In the follow-up study, it is thought that actual clothing experiments and studies to develop clothing patterns by applying them to obese male tops in their 20s should be conducted.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.96-104
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• 1995

A study for a lathe to machine workpiece with noncircular cross-section is presented. The noncircular cutting is accomplished by controlling radial tool position synchronized with revolution angle of the spindle according to the desired cross-sectional shape. A learning control algorithm is suggested for the tool positioning. The learning law of the algorithm is based on pole-zero cancellation, which guarantees the control stability. The control performances are analyzed and simulated on a numerical computer that the effectiveness of the control algorithm is convinced. The algorithm is tested on a conventional NC-lathe which shows some successful results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.46-55
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• 2016

Three small scale hollow circular reinforced concrete columns(4.5 aspect ratio) were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable are transverse steel ratio. Volumetric ratio of spirals of all the columns is 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The final objectives of this study are to provide quantitative reference data and tendency for performance or damage assessment based on the performance levels such as cracking, yielding, steel fracture, etc. In this paper, describes mainly failure behavior, strength degradation behaviour, displacement ductility of circular reinforced concrete bridge columns with respect to test variables.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.127-137
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• 2003

In locations where the cost of concrete is relatively high, or in situations where the weight of concrete members is to be kept to a minimum, it may be economical to use hollow R.C. members. The ductility of circular hollow R.C. columns with one layer of longitudinal and spiral reinforcement placed near the outside face of the section and the steel tube placed on the inside face of the section is investigated. Such hollow sections are confined through the wall thickness since the steel tube is placed. In this study, moment-curvature analyses are conducted with Mander's confined concrete stress-strain relationship. The variables influenced on the ultimate strain is the ratio and yield strength of confining reinforcement and the compression strength for confined concrete. From this ultimate strain - the transverse reinforcement ratio relationship, the transverse reinforcement ratio for circular hollow reinforced columns with confinement is proposed. The proposed transverse reinforcement ratio is confirmed by experimental results.

• Proceedings of the Korea Society of Costume Conference
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• 2003.05a
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• pp.34-34
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• 2003

본 연구는 체형의 특성이 현저히 나타나는 40~50대의 Plus-size 여성을 대상으로 체형의 특징이 고려된 치수체계에 대해 맞음새가 우수한 재킷을 개발하고, 이 원형을 토대로 하여 체형의 단점을 보완할 시각적 효과를 연구하기 위해 Plus-size에 해당하는 여성을 선정하여 수트(suit)를 제작한 후 착의 평가하여 Plus-size에 적합한 수트를 제안하는데 목적을 두고 있다. 결과를 요약하면 다음과 같다. 1. Plus-size 여성의 착용실태를 파악하기 위해 실시한 착용실태 조사는 판매자의 측면의 심층면접과 소비자 측면의 착장조사로 구분하여 조사하고 분석하였다. 착용실태조사 결과, Plus-size 여성은 의복구매시 맞음새와 편안함을 중시하고 상완부와 어깨의 두께, 가슴둘레와 복부의 비만등의 체형단점을 갖게 되므로 판매자측에서는 의복제도 시에 등품, 앞품, 상완부, 복부의 여유분을 고려하고 있었다. 시각적 효과로는 세미피트 스타일의 프린세스 라인과 허리선+20, 30cm의 재킷길이, 그리고 테일러드 칼라, 스테인 칼라, 라운드 네크라인이 판매자과 소비자의 양측면에서 선호되고 있었다. 2. Plus-size 여성의 체형에 맞음새가 우수한 재킷원형을 개발하기 위해 Plus-size 여성복의 재킷 원형 중 4종의 기존원형을 선정하고, 착의 피험자 3인을 대상으로 3차에 걸친 착의실험을 통해 연구 원형을 개발하고 평가단을 구성해 객관적인 평가 33문항에 대한 외관 관능검사를 실시하였다. 1) 가슴둘레 여유분을 8~9cm, 허리둘레 여유분을 6~7cm, 엉덩이둘레 여유분을 6~8cm로 적용하여 맞음새를 향상시켜 날씬해 보이는 효과를 높였다. 2) 진동깊이 계산식은 (B/10+10.5)+2cm 적용하고, 진동두께 계산식은 (B/8-1.5)+2cm를 적용함으로써 진동깊이와 진동두께의 편차가 작아짐으로 인해 소매부위와 진동부위의 맞음새를 향상시켰다. 3) 가슴둘레의 증가에 따라 등길이에 앞길이 치수를 증가시키는 계산식을 설정하여 앞가슴둘레의 맞음새를 향상시켰다. 4) Plus-size여성의 경우 허리부분의 신체적합성을 높이기 위하여 사이드 판넬(side panel)의 재킷원형으로 하였다. 앞 허리와 배 부분의 지방 침착이 크므로 앞 허리둘레 다아트 폭과 앞판 사이드 판넬(side panel) 솔기 다아트 폭을 작게 설정하고, 뒤판 사이드 판넬 솔기 폭을 크게 설정하였다. 5) 어깨끝점 사이길이는 다른 부위의 체지방 침착과 같이 비례적으로 증가하지 않으므로 표준체형에 비해 좁게 설정하였다.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.101-109
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• 2004

In order to enhance the productivity of AVM $B_{la}$ produced by Streptomyces avermitilis as a secondary metabolite, we established a basic protocol necessary for protoplast fusion with high-producing strains as a fusion partner, and then obtained various kinds offusants by adopting a massive strain-development procedure (a miniaturized strain screening system). An alternative fusion method using UV and/or NTG mutation of protoplasts was developed to screen genetic recombinants without specific selectable markers. In this method, the mutants obtained by protoplast fusion after UV and/or NTG treatment (95% death rate) of the respective fusion partner (protoplasts of the respective mutants resistant against L-isoleucine antimetabolites such as O-methylthreonine and/or azaleucine) were regarded as DNA-recombined protoplast fusants. Notably it was demonstrated that most of the protoplast recombinants obtained by the UV mutation method were able to biosynthesize higher amount of AVM $B_{la}$ , reaching almost three times higher level (almost equal to the industrial productivity), compared to the average AVM Bla amount of the parallel mother strains.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.81-88
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• 1999

In order to properly evaluate the shear strength of reinforced concrete circular columns due to the transverse shear reinforcement, the average of fractions of forces generated along the circular transverse hoops across the shear failure plane in the loading direction is calculated. For this, the center-to-center diameter of circular transverse hoops. spacing and the crack angle measured to the column longitudinal axis are considered. Using these variables, an equation representing the effective section area of circular transverse shear steel is proposed. The study result shows that the constant parameter. used for the calculation of the effective section area of circular hoops over the last 10 years, should not universally be applied any more. The use of the constant parameter may not seriously do harm to the evaluation of shear strength for circular columns with non-seismically designed transverse hoop reinforcement, since it gives slightly conservative results. However. for well-confined circular columns with close spacing or circular steel jacketing. it gives about 20% overestimation of the shear capacity contributed by the transverse hoop steel.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.643-650
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• 2020

The phased array antenna has an advantage enabling rapid beam aim without the mechanical rotation of the antenna, because it arranges multiple elements in a linear or planer (grid or circular) and electronically controls the phase for each element. The planar array antenna is generally used a grid array and a circular array, and the circular form has the higher resolution comparing to the grid form due to the its structural characteristics. However, a concentric circular array (CCA) or a concentric ring array (CRA) with multiple circular arrays which each has different radius is used in the limited area, because the entire radius should be increased for the circular array with a number of elements. In this paper, we introduce the angle-of-arrival (AOA) estimator for an adaptive beamforming satellite system based on CRA and provide the simulation results for performance evaluation. In addition, simulation results are compared and analyzed to the case for the circular array antenna.