• 한국정보과학회논문지:시스템및이론
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• 제30권1호
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• pp.1-11
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• 2003

프래그멘테이션은 다수의 사용자를 지원하는 대규모 멀티컴퓨터 시스템의 성능에 병목현상을 초래하는 주요 요인이다. 본 논문에서는 프래그멘테이션을 줄이기 위해서, 할당되는 프로세서들이 형성하는 모양이 직사각형이어야 한다는 제약조건을 완화시킨 LSSA(L-Shaped Submesh Allocation) 기법을 제안한다. LSSA 기법은 단편화된 메쉬 시스템에도 전용될 수 있도록 직사각형 뿐 만 아니라. 변형된 L자 모양의 서브메쉬를 할당할 수 있다. 그러므로 LSSA 기법은 시스템으로 들어오는 작업을 다른 기법들보다 빨리 수용할 수 있으며, 이로 인해 작업응답시간을 줄일 수 있다. 시뮬레이션 결과를 통해서 LSSA 기법이 외부 프래그멘테이션, 작업응답시간, 그리고 시스템의 활용도 면에서 다른 기법들보다 우수함을 보인다.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.204-217
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• 2016

Modified poplar has emerged as a potential raw material for furniture production. Lack of specific modified poplar strength information; however, restricts applications in the furniture industry especially as related to strength in corner-joints. Optimization of strength in L-shaped corner dowel modified poplar joints under compression loads utilizing finite element analysis (FEA) by Taguchi method with the focus of this study. Four experiment factors (i.e., Structure Style, Tenon Length, Tenon Diameter, and Tenon Gap), each at three levels, were conducted by adopting a $L_9-3^4$ Taguchi orthodoxy array (OA) to determine the optimal combination of factors and levels for the von Mises stress utilizing ANSYS software. Results of Signal-to-Noise ratio (S/N) analysis and the analysis of variance (ANOVA) revealed the optimal L-shaped corner dowel joint in modified poplar is $45^{\circ}$ Bevel Butt in structure style, 24 mm in tenon length, 6 mm in tenon diameter, and 20 mm in tenon gap. Tenon length and tenon gap are determined to be significant design factors for affecting von Mises Stress. Confirmation tests with optimal levels and experimental test indicated the predicted optimal condition is comparable to the actual experimental optimal condition.

• 한국기계가공학회지
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• 제20권11호
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• pp.52-59
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• 2021

Titanium alloy (Ti-alloy) is widely used as a material for core parts of aircraft structures and engines that require both lightweight and heat-resistant properties owing to their high specific stiffness. Most parts used in aircraft have I-, L-, and H-shaped thin-walled structures for weight reduction. It is difficult to machine thin-walled structures owing to vibrations and deformations during machining. In particular, cutting tool damage occurs in the corners of thin-walled structures owing to the rapid increase in cutting force and vibration, and machining quality deteriorates because of deep tool marks on machined surfaces. In this study, milling experiments were performed to derive an effective method for machining a L-shaped thin-walled structure with Ti-alloy (Ti-6Al-4V). Three types of machining experiment were performed. The surface quality, tool wear, cutting force, and vibration were analyzed comprehensively, and an effective machining method in terms of tool life and machining quality was derived.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.171-172
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• 2018

Dual gate L-shaped tunnel field-effect-transistor (DG-LTFET) is presented in this study. DG-LTFET achieves near vertical subthreshold slope (SS) and its ON current is also found to be higher then both conventional TFET and LTFET. This device could serve as a potential replacement for conventional complimentary metal-oxide-semiconductor (CMOS) technology.

• Journal of applied mathematics & informatics
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• 제13권1_2호
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• pp.261-275
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• 2003

In this paper we study two stage problems of stochastic convex programming. Solving the problems is very hard. A L-shaped method for it is given. The implement of the algorithm is simple, so less computation work is needed. The result of computation shows that the algorithm is effective.

• 한국경영과학회지
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• 제22권1호
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• pp.1-24
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• 1997

In this paper, we have proposed new solution methods to solve TSLP (two-stage stochastic linear programming) problems. One solution method is to combine the analytic center concept with Benders' decomposition strategy to solve TSLP problems. Another method is to apply an idea proposed by Geoffrion and Graves to modify the L-shaped algorithm and the analytic center algorithm. We have compared the numerical performance of the proposed algorithms to that of the existing algorithm, the L-shaped algorithm. To effectively compare those algorithms, we have had computational experiments for seven test problems.

• 복식문화연구
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• 제10권5호
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• pp.485-492
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• 2002

The purpose of this study is to classify of the Cone shaped Pendants in old tombs of Three Kingdom States. These Cone shaped Pendants are made of bronze and coated with gold plate or Gold. Each Cone shaped Pendants consists of a Sehwhan(細環) type or Taewhan type, a median part in the form of a several joined small globe, or circular shape, and finally a cone-shared pendant. Cone shaped Pendants is 5 part(A-L A-b, B-1-a, B-1-b, B-2-b type) in according to the styles of the Sehwhan(細環) and Taewhan type and median ornament types. A-a, A-b, B-1-a, B-1-b type was general style that was found in most of the old tombs in Kokuryo, Pacjae, ancient Silla. B-2-b type was excavated from the only Kokuryo tombs.

• 한국항공운항학회지
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• 제29권4호
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• pp.78-87
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• 2021

This study is to evaluate the applicability and performance of trapezoidal-shaped grooves on domestic airport runways. For this, the constructability, drainage performance, and friction resistance characteristics of trapezoidal-shaped grooves compared to square-shaped grooves were evaluated through test construction on pavement at Incheon Airport. As a result of the test construction, the trapezoidal-shaped grooves satisfies the required geometry standards and tolerance, and secured a macrotexture that was 25% improved compared to the square-shaped grooves. It was confirmed that trapezoid-shaped grooves secured drainage performance of more than 7-9%, and surface friction performance improved compared to existing grooves when the surface of the pavement was wet as the test speed increased in the dry state. In addition, after trapezoidal-shaped grooves was installed on the RWY 16R/34L of Incheon Airport, the friction coefficient was 0.84, which satisfies the design level of the new runway surface of 0.82 at the test speed.

• 한국항행학회논문지
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• 제19권6호
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• pp.623-629
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• 2015

본 논문에서 CDMA (1.85~2.12 GHz) 및 2.4 GHz WLAN (2.4~2.484 GHz) 이중대역 사용이 가능하면서 무지향성 방사패턴을 가질 수 있도록 역 L-형 슬롯을 가진 CPW (coplanar waveguide) 급전 인쇄형 모노폴 안테나를 새롭게 제안하였다. 제안된 안테나는 2.4 GHz WLAN (wireless local area network) 대역에서 임피던스 대역폭을 증가시키기 위해 기존의 n-형 슬롯을 대신하여 역 L-형 슬롯이 인쇄된 방사 모노폴에 에칭 된다. 제안된 안테나는 크기가 $50{\times}25mm^2$이고 두께가 1.6 mm, 유전상수가 4.4인 FR4 기판의 한쪽 면에서 설계 및 제작되었다. 제작된 안테나의 측정결과, 임피던스 대역폭($S_{11}{\leq}-10dB$)이 CDMA (code division multiple access) 주파수 대역에서는 280 MHz (1.84~2.12 GHz), WLAN 주파수 대역에서는 420 MHz (2.38~2.8 GHz)인 대역폭을 얻을 수 있었다. 역 L-형 슬롯 사용의 결과로 WLAN 대역에서 기존의 n-형 슬롯의 사용결과 140 MHz (2.39~2.53 GHz)에 비해 대역폭이 3배가량 증가된 점은 주목할 만한 결과이다. 또한 사용 주파수 전 대역에서 좋은 무지향성 방사패턴을 얻을 수 있었다.

• 대한전자공학회논문지TC
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• 제43권5호
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• pp.169-175
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• 2006

본 논문에서는 GPS 수신용 안테나인 T형 슬릿을 갖는 마이크로스트립 패치 안테나를 설계 제작하였다. T형 슬릿을 삽입한 마이크로스트립 패치 안테나는 슬릿이 없는 패치 안테나 보다 낮은 주파수에서 공진한다. 이것으로부터 패치의 크기를 축소시킬 수 있다. T형 슬릿를 갖는 마이크로스트립 패치 안테나의 공진 주파수를 계산하기 위하여 패치 표면의 전류 분포로 부터 공진 주파수 공식을 유도하였다. Ensemble 6.0을 이용하여 근사식의 정확성을 검증하였다. 이렇게 구해진 공식을 이용하여 1.575GHz에서 동작하는 최적의 안테나를 설계하였으며, 그 결과 T형 슬릿을 갖는 안테나의 경우 29%까지 안테나의 크기를 감소시킬 수 있었다. 또한 슬릿을 갖는 마이크로스트립 안테나는 대역폭은 매우 좁기 때문에 협대역 특성을 개선하기 위해 구형 슬릇을 갖는 마이크로스트립 패치 안테나를 제안하였다. 제작된 T형을 갖는 마이크로스트립 패치 안테나의 공진 주파수는 1.575GHz이고 대역폭은 50MHz를 얻었다.