• 한국경영과학회지
• /
• 제27권4호
• /
• pp.1-10
• /
• 2002

The ring routing and wavelength assignment problem arose in the planning of optical communication networks which use WDM rings. Traffic demands are given for each pair of nodes in an ring : each demand must be routed one of the two possible connections round the ring and the wavelength assignments must be made so that there are no conflicts : that is. no two connections whose routes share a link can be assigned the same wavelength along that link. The objective is to minimize the number of used wavelengths. We propose the local optimal routing for the problem and show that there always exists an optimal solution satisfying it. Furthermore we suggest a new lower bound for the problem and show that it is very efficient for the worst case example.

• Current Optics and Photonics
• /
• 제2권4호
• /
• pp.356-360
• /
• 2018

We demonstrate continuous-wave operation of an all-fiber thulium-holmium codoped laser operating at a wavelength of 1706.3 nm. To realize laser operation in the short-wavelength region of the emission-band edge of thulium in silica fiber, we employ fiber Bragg gratings having resonant reflection at a wavelength around 1700 nm as a wavelength-selective mirror in an all-fiber cavity scheme. We first examine the performance of the laser by adjusting the central wavelength of the in-band pump source. Although a pump source possessing a longer wavelength is observed to provide reduced laser threshold power and increased slope efficiency, because of the characteristics of spectral response in the gain fiber, we find that the optimal pump wavelength is 1565 nm to obtain maximum laser output power for a given system. We further explore the properties of the laser by varying the fiber gain length from 1 m to 1.4 m, for the purpose of power scaling. It is revealed that the laser shows optimal performance in terms of output power and slope efficiency at a gain length of 1.3 m, where we obtain a maximum output power of 249 mW for an applied pump power of 2.1 W. A maximum slope efficiency is also estimated to be 23% under these conditions.

• ETRI Journal
• /
• 제37권5호
• /
• pp.888-897
• /
• 2015

Group scheduling is an operation whereby control packets arriving in a time slot schedule their bursts simultaneously. Normally, those bursts that are of the same wavelength are scheduled on the same channel. In cases where the support of full wavelength converters is available, such scheduling can be performed on multiple channels for those bursts that are of an arbitrary wavelength. This paper presents a new algorithm for group scheduling on multiple channels. In our approach, to reach a near-optimal schedule, a maximum-weight clique needs to be determined; thus, we propose an additional algorithm for this purpose. Analysis and simulation results indicate that an optimal schedule is almost attainable, while the complexity of computation and that of implementation are reduced.

• 한국통신학회논문지
• /
• 제27권6B호
• /
• pp.645-651
• /
• 2002

본 논문은 OMS(Optical Multiplex Section) 또는 OCh (Optical Channel) SPRING (Shared Protection Ring)에 적용되는 두 가지 광파장 할당 알고리즘을 제안하고 시뮬레이션을 통해 특성을 비교하였다. 제안한 알고리즘들은 WDM SPRING 네트워크에 적용할 수 있는 최적화 알고리즘과 넌블러킹 알고리즘이며 대부분의 비교에서 최적화 알고리즘이 넌블러킹 알고리즘에 비해 우수함을 보였다. 하지만, 넌블러킹 알고리즘도 몇몇 기존 연결을 재구성하기 위한 광파장 연결이나 할당을 필요로 하지 않는 중요한 잇점이 있다.

• Near Infrared Analysis
• /
• 제1권1호
• /
• pp.1-7
• /
• 2000

A convenient algorithm for optimizing wavelength selection in multiple linear regression (MLR) has been developed. MOP (MLP Optimization Program) has been developed to test all possible MLR calibration models in a given spectral range and finally find an optimal MLR model with external validation capability. MOP generates all calibration models from all possible combinations of wavelength, and simultaneously calculates SEC (Standard Error of Calibration) and SEV (Standard Error of Validation) by predicting samples in a validation data set. Finally, with determined SEC and SEV, it calculates another parameter called SAD (Sum of SEC, SEV, and Absolute Difference between SEC and SEV: sum(SEC+SEV+Abs(SEC-SEV)). SAD is an useful parameter to find an optimal calibration model without over-fitting by simultaneously evaluating SEC, SEV, and difference of error between calibration and validation. The calibration model corresponding to the smallest SAD value is chosen as an optimum because the errors in both calibration and validation are minimal as well as similar in scale. To evaluate the capability of MOP, the determination of benzene content in unleaded gasoline has been examined. MOP successfully found the optimal calibration model and showed the better calibration and independent prediction performance compared to conventional MLR calibration.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
• /
• pp.158-159
• /
• 2003

In four-wave-mixing wavelength converter, we investigated the performance through simulation by using VPI tool, changing the input signal power and CW power at 2.SGb／s. Controlling optimal CW power to each input signal power, we extended the input signal power range to 20dB, which guarantees the minimum power penalty.

• 조명전기설비학회논문지
• /
• 제26권1호
• /
• pp.15-21
• /
• 2012

In this study, the characteristics of the 2-wavelength white organic light-emitting diod (WOLED) with two colors of yellow and blue were compared and analyzed with 3-wavelength WOLED with three colors of red, green, and blue. The results indicated that the power efficiency of the 2-wavelength WOLED was 1.6 times higher than 3-wavelength WOLED. In addition, the colot coordinate of the 2-wavelenth WOLED which was (0.34, 0.39) was found closer to the optimal color coordinate for the white-lighting application when compared with that of the 3-wavelength WOLED.

• ETRI Journal
• /
• 제24권2호
• /
• pp.131-141
• /
• 2002

This paper considers a routing and wavelength assignment problem (RWAP) for the implementation of efficient Wavelength Division Multiplexing all-optical mesh networks without wavelength conversion. For a given physical network and required connections, the solution to the RWAP consists in how to select a suitable path and wavelength among the many possible choices for each connection so that no two paths using the same wavelength pass through the same link, while minimizing the number of required wavelengths. We introduce an integer programming formulation of the RWAP, which has an exponential number of variables, and propose an algorithm to solve it based on the column generation technique. The proposed algorithm can yield high quality solutions and tight lower bounds at the same time. Though the proposed algorithm cannot guarantee optimal solutions, computational results show that the algorithm yields provably good solutions within a reasonable time.

• 대한전자공학회논문지
• /
• 제19권6호
• /
• pp.80-83
• /
• 1982

X-밴드 주파수에서 λg/4 개방 마이크로스트립 선로 급전형 스로트 점렬을 구현하였다. 최적 급전점은 실험적으로 결정하였고 스로트 점각의 여러 주파수에서 입력 임피던스와 복재 패턴을 측정하였으며 다소 다른 길이의 16개 소자와 본 논문에서 제시한 급전 선로를 사용하여 주파수 대역을 증가시켜 보았다. A quarter-wavelength open circuited microstripline slot array is realized at X-band froquency. The optimal feeding point is experimentally determined. The input impedance of the slot array for various frequencies and its radiation pattern are measured. The bandwidth of the slot array is increased by using the 4×4 elements which are slightly different in length and feeding network which is suggested in this papers.

• 한국산학기술학회논문지
• /
• 제11권12호
• /
• pp.4735-4741
• /
• 2010

초음파 금속 용착은 신소재, 도금 구조물 등과 같은 다양한 재료의 용착에 대한 가능성 때문에 광범위한 분야에서 사용되고 있으며 용착 조건도 다양하다. 본 연구에서는, 이종 금속 박판의 초음파 금속 용착을 위해 설계된 단부가형 한파장 혼은 유한요소해석 하였다. 유한유소해석은 초음파 혼의 최적 설계와 초음파 공구혼의 고유 주파수를 예상하기 위해 사용되었다. 그리고 설계된 한파장 스텝 혼은 고유 주파수 분석 시스템을 사용하여 실험적으로 검증하였다.