• 전자공학회논문지A
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• 제31A권2호
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• pp.9-17
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• 1994

This paper proposes Double queue threshold QLT(Queue Length Threshold) algorithm and Hysteresis effect QLT algorithm. as being DPS(Dynamic Priority Scheduling) techniques. in order to advance the processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed through computer simulations,and the priority scheduling is analyzed using a retrial queue with two types of calls. Our simulation results show that the performance of the proposed Double queue length threshold QLT algorithm is superior to that of the conventinal QLT algorithm for 2 or more classes delay sensitive traffics. Also we find that Hysteresis effecT QLT algorithm is better mechanism than that of the existing QLT for real time and non-real time traffics.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.311-324
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• 2018

Herein,the Neodymium ion ($Nd^{3+}$) doped CoAl-LDH have been successfully prepared via co-precipitation method and was used as a precursor of Nd-doped CoAl-mixed metal oxides (MMO). The photocatalytic activity of doped LDH and MMO was investigated in the degradation of an azo dye, C.I. Acid Red 14, under visible light irradiation. DRS and PL analysis demonstrated decreasing in the band gap energy and recombination of photo-induced charge carriers of Nd-doped LDH and MMO compared with the pristine CoAL-LDH. Due to significant difference in photocatalytic performance. A power law empirical kinetic model was obtained for predicting the photocatalytic degradation efficiency.

• 한국자기학회지
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• 제26권6호
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• pp.206-212
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• 2016

대형 전동기에서 영구자석을 받치는 철제 받침대의 형상은 요크와의 결합력을 결정하는 매우 중요한 요소이다. 대형 전동기에서 받침대의 형상에 따라 요크와의 결합력 차이가 있다. 이 논문에서는 이중 받침대(Double bed)와 단일 받침대(Single bed)의 결합력을 가상공극 법을 통해 계산하여 차이점과 문제점을 제시하고 단일 받침대가 결합력 향상 측면에서 우위에 있음을 보여준다. 또한 받침대의 아래에 홈(Groove) 형상을 새김으로해서 받침대와 요크 간의 결합력이 향상됨을 보인다

• 한국유체기계학회 논문집
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• 제17권1호
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• pp.28-34
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• 2014

This paper presents the performance enhancement of a double-inlet centrifugal blower by the shape optimization of an impeller. Two design variables, a number of blade and a length of chord, are introduced, and analyzed by a response surface method. Three-dimensional compressible Navier-Stokes equations are used to analyze the blower performance and the internal flow of the blower. Throughout the numerical simulation of the blower, blower efficiency can be increased by reducing separation flow generating from the blade leading edge of a blade pressure surface. It is noted that recirculation flow observed inside the blade passage induces low velocity region, thus increases pressure loss. Efficiency and pressure of the optimum blower are successfully increased up to 3% and 3.9% compared to those of reference blower at the design flow condition, respectively. Detailed flow field inside the blower is also analyzed and compared.

• Journal of Electrochemical Science and Technology
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• 제1권1호
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• pp.63-68
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• 2010

The $Li_4Ti_5O_{12}$/AC composite was prepared by sol-gel process with ultrasonication. The prepared composite was characterized by SEM, XRD and TG analysis, and their electrochemical behaviors were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge test in 1M $LiBF_4$/PC electrolyte. From the results, the $Li_4Ti_5O_{12}$ particles coated on AC surface had an average particle size of 100 nm and showed spinel-framework structure. When the potential range of the $Li_4Ti_5O_{12}$/AC composite was extended from 0.1 to 2.5 V, redox peaks and electric double layer property were revealed. The initial discharge capacity of $Li_4Ti_5O_{12}$/AC composite was 218 mAh $g^{-1}$ at 1 C. The enhancement of discharge capacity was attributed to electric double layer of added activated carbon.

• 한국인터넷방송통신학회논문지
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• 제12권2호
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• pp.221-232
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• 2012

이중 밀도 이산 웨이브렛 변환은 정밀하게 표본화되는 이산 웨이브렛 변환에 중요한 특징을 추가하여 그 성능을 개선한 것이다. 우선적으로 이 변환은 하나의 스케일링 함수와 두 개의 웨이브렛 함수로 구성된다. 즉, 3개 채널로 분해가 되며 두 웨이브렛 함수는 주파수 대역을 1/2씩 분할하도록 설계되었다. 따라서 입력 데이터보다 더 많은 양의 부대역 데이터들을 생성하면서도 완전재생을 만족한다. 또한 근사적으로 이동 불변의 특징을 만족하도록 설계되었다. 그러나 웨이브렛들이 모든 방향성을 반영하지 못하는 제약성을 갖는다. 즉, 이중 밀도 이산 웨이브렛 변환이 기존의 웨이브렛 변환보다 우수하지만, 다양한 방향성의 부족으로 그에 대한 처리가 제약받는다. 본 논문에서 제안된 방법은 이중 밀도 이산 웨이브렛 변환에 quincunx 표본화를 결합하여 각각의 장점을 얻도록 하였다. 특히, quincunx 표본화는 더 많은 방향성을 생성할 수 있다. 결과적으로 제안된 방법이 다양한 각도의 회전된 부영상을 생성할 수 있기 때문에 영상처리 영역에서 향상된 성능을 제공할 수 있다.

• Advances in Computational Design
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• 제4권4호
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• pp.327-342
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• 2019

Rehabilitation and retrofitting of structures designed in accordance to standard design codes is an essential practice in structural engineering and design. For steel structures, one of the challenges is to strengthen the panel zone as well as its analysis in moment-resisting frames. In this research, investigations were undertaken to analyze the influence of the panel zone in the response of structural frames through a computational approach using ETABS software. Moment-resisting frames of six stories were studied in supposition of real panel zone, different values of rigid zone factor, different thickness of double plates, and both double plates and rigid zone factor together. The frames were analyzed, designed and validated in accordance to Iranian steel building code. The results of drift values for six stories building models were plotted. After verifying and comparing the results, the findings showed that the rigidity lead to reduction in drifts of frames and also as a result, lower rigidity will be used for high rise building and higher rigidity will be used for low rise building. In frames with story drifts more than the permitted rate, where the frames are considered as the weaker panel zone area, the story drifts can be limited by strengthening the panel zone with double plates. It should be noted that higher thickness of double plates and higher rigidity of panel zone will result in enhancement of the non-linear deformation rates in beam elements. The resulting deformations of the panel zone due to this modification can have significant influence on the elastic and inelastic behavior of the frames.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.9-11
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• 2000

To increase the device linearities and the breakdown-voltages of FETs, Al$\sub$0.25/ Ga$\sub$0.75/AS / In$\sub$0.25/Ga$\sub$0.75/As / Partially doped channel FET(DCFET) structures are proposed. The metal- insulator -semiconductor (MIS) like structures show the high gate-drain breakdown voltage(-20 V) and high linearities. The devices showed the small ripple of the current cut-off frequency and the power cut-off frequency over the wide bias range.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1986년도 춘계학술발표회 논문집
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• pp.206-210
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• 1986

Double Ion Implantation methods are used to improve the stiffness os carrier profiles, and then the analytical solutions to Poisson`s equation are derived with summation of each carrier profile. Numerical analyses are done using profer boudary conditions and the results show that the improvement of voltage-dependent-capacitance ratio (C(!)/C(25)) is obtained up to B.6. The third ion implantation is for the enhancement of the Schottky barrier height.

• 대한원격탐사학회지
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• 제33권2호
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• pp.159-169
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• 2017

위성용 전자광학탑재체는 제한된 소모전력 및 우주방사선과 같은 사용 환경에 의해 설계부터 특별한 요구사항을 가지고 있으며, 획득 영상의 품질은 주로 GSD (Ground Sampled Distance), 신호대잡음비(SNR, Signal to Noise Ratio), MTF (Modulation Transfer Function)에 따라 좌우된다. 영상센서의 출력신호에 포함된 잡음 감소를 통한 신호대잡음비 개선을 위하여, 센서에 추가된 프리픽셀(Pre-pixel) 및 다크픽셀(Dark-pixel)을 사용하여 CDS (Corrective Double Sampling) 방식을 통해 영상센서의 잡음 성분을 포함한 오프셋 신호(Offset Signal)를 제거하는 아날로그 신호처리(ASP, Analog Signal Processor) 방법을 제안한다. 또한 센서 제어시스템에서는 영상의 불균일성 처리를 위해 제어시스템의 출력 포트별 게인(Gain), 오프셋, 및 센서의 화소별 특성을 반영한 다양한 방식에 의한 보정 방법이 적용된다. 본 논문에서는 이상 설명한 여러 가지 잡음 개선방법을 시스템 설계 및 운영에 적용하여 위성탑재용 전자광학카메라의 신호대잡음비 향상 방법을 제안하고, 실험을 통해 검증한다.