• Journal of Information Display
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• 제9권3호
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• pp.23-27
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• 2008

This paper reports that well-balanced white emission with three primary colors can be achieved with a simple white organic light-emitting diode (WOLED) structure of ITO / $\alpha$-NPD (50 nm) / $\alpha$-NPD: Btp2Ir(acac) (8 wt%, 6 nm) / $\alpha$-NPD (5 nm) / BCP (3 nm) / $Alq_3$: C545T (0.5 wt%, 10 nm) / $Alq_3$ (40 nm) / LiF (0.5 nm) / Al (100 nm). The external quantum efficiency of the device reached 3.8% at a current density (luminance) of 4.6 mA/$cm^2$ (310 cd/$m^2$), and the maximal luminance of the device reached 19,000 cd/$m^2$ at 11.5 V. The insignificant blue shift of the emitting color with an increasing current density can be attributed to the narrowing of the exciton formation zone width.

• 한국컴퓨터정보학회논문지
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• 제25권1호
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• pp.21-27
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• 2020

본 논문에서는 전투관리체계의 QoS를 향상시키기 위해 동적 가중 결손 라운드로빈과 우선 순위 기반의 혼합 스케줄링 알고리즘을 제안한다. 제안된 알고리즘인 DWDRR은 큐의 트래픽과 중요도에 따라 가중치를 동적으로 부여하여 패킷을 전송하는 방법이다. 제안된 알고리즘의 타당성을 분석하기 위해 모의실험을 통해 제안된 알고리즘이 특정구간에서 높은 효율성을 나타내는 것을 증명하였다. 따라서 기존의 알고리즘과 제안된 알고리즘을 혼합하여 사용하는 방법을 제안한다. 또한, 빈번한 기법 전환을 방지하기 위해 히스테리시스 기법을 적용하였다. 제안한 알고리즘은 동일한 트래픽에서 기존 알고리즘보다 낮은 패킷 손실률과 지연 시간을 나타낸다.

• Progress in Superconductivity
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• 제6권2호
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• pp.104-107
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• 2005

We have developed and tested an RSFQ 4-bit Arithmetic Logic Unit (ALU) based on half adder cells and de switches. ALU is a core element of a computer processor that performs arithmetic and logic operations on the operands in computer instruction words. The designed ALU had limited operation functions of OR, AND, XOR, and ADD. It had a pipeline structure. We have simulated the circuit by using Josephson circuit simulation tools in order to reduce the timing problem, and confirmed the correct operation of the designed ALU. We used simulation tools of $XIC^{TM},\;WRspice^{TM}$, and Julia. The fabricated 4-bit ALU circuit had a size of $\3000{\ cal}um{\times}1500{\cal}$, and the chip size was $5{\cal} mm{\times}5{\cal}mm$. The test speeds were 1000 kHz and 5 GHz. For high-speed test, we used an eye-diagram technique. Our 4-bit ALU operated correctly up to 5 GHz clock frequency. The chip was tested at the liquid-helium temperature.

• 한국정보통신학회논문지
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• 제6권6호
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• pp.863-872
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• 2002

Real-time(RT) object-oriented(00) distributed computing is a form of RT distributed computing realized with a distributed computer system structured in the form of an object network. Several approached proposed in recent years for extending the conventional object structuring scheme to suit RT applications, are briefly reviewed. Then the approach named the TMO(Time-triggered Message-triggered Object) structuring scheme was formulated with the goal of instigating a quantum productivity jump in the design of distributed time triggered simulation. The TMO scheme is intended to facilitate the pursuit of a new paradigm in designing distributed time triggered simulation which is to realize real-time computing with a common and general design style that does not alienate the main-stream computing industry and yet to allow system engineers to confidently produce certifiable distributed time triggered simulation for safety-critical applications. The TMO structuring scheme is a syntactically simple but semantically powerful extension of the conventional object structuring approached and as such, its support tools can be based on various well-established 00 programming languages such as C++ and on ubiquitous commercial RT operating system kernels. The Scheme enables a great reduction of the designers efforts in guaranteeing timely service capabilities of application systems.

• Progress in Superconductivity
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• 제7권2호
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• pp.109-113
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• 2006

The Arithmetic Logic Unit (ALU) is a core element of a computer processor that performs arithmetic and logic operations on the operands in computer instruction words. We have developed and tested an RSFQ multi-bit ALU constructed with half adder unit cells. To reduce the complexity of the ALU, We used half adder unit cells. The unit cells were constructed of one half adder and three de switches. The timing problem in the complex circuits has been a very important issue. We have calculated the delay time of all components in the circuit by using Josephson circuit simulation tools of XIC, $WRspice^{TM}$, and Julia. To make the circuit work faster, we used a forward clocking scheme. This required a careful design of timing between clock and data pulses in ALU. The designed ALU had limited operation functions of OR, AND, XOR, and ADD. It had a pipeline structure. The fabricated 1-bit, 2-bit, and 4-bit ALU circuits were tested at a few kilo-hertz clock frequency as well as a few tens giga-hertz clock frequency, respectively. For high-speed tests, we used an eye-diagram technique. Our 4-bit ALU operated correctly at up to 5 GHz clock frequency.

• 한국컴퓨터정보학회논문지
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• 제10권1호
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• pp.1-6
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• 2005

백색발광은 풀칼라, 백라이트 및 조명을 위한 전자발광 소자로의 응용에 매우 중요하다. 본 논문에서는 오렌지 발광을 내는 Rubrene 색소를 포함하는 청색 재료인 nitro-DPVT 박막을 사용한 단분자 유기 백색발광소자를 구현하였다. 제작된 소자의 기본적 구조는 ${\alpha}-NPD/nitro-DPVT/nitro-DPVT:Rubrene/BCP/Alq3.$이다. 알루미늄은 음극재료로 사용하였으며 양극 재료는 ITO를 사용하였다. 백색 발광 스펙트럼은 가시광선 전 영역에 걸쳐 나타났고 14V에서 발광된 빛의 C.I.E 색좌표는 (0.3347,0.3515)이다. 동작개시 전압은 2.5V이하에서 나타났고 양자효율은 $0.35\%$이었다.

• 한국전기전자재료학회논문지
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• 제26권1호
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• pp.18-21
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• 2013

$SiO_2$ layer grown by rapid thermal oxidation and $SiN_x$ layer were used for passivating the surface of n-type silicon solar cell, instead of only $SiN_x$ layer generally used in photovoltaic industry. The rapid thermal oxidation provides the reduction of processing time and avoids bulk life time degradation during the processing. Improvement of 30 mV in Voc and $2.7mA/cm^2$ in Jsc was obtained by applying these two layers. This improvement led to fabrication of a large area ($239cm^2$) n-type solar cell with 17.34% efficiency. Internal quantum efficiency measurement indicates that the improvement comes from the front side passivation, but not the rear side, by using $SiO_2/SiN_x$ stack.

• International Journal of Internet, Broadcasting and Communication
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• 제10권3호
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• pp.59-64
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• 2018

A cooperative spectrum sensing has been proposed to improve the sensing performance in cognitive radio (CR) network. However, cooperative sensing causes additional overhead for reporting the result of local sensing to the fusion center. In this paper, we propose a technique to reduce the overhead of data transmission of cooperative sensing for applying the quantum data fusion technique in cognitive radio networks by omitting the lowest quantized in the local sensed results. If a CR node senses the lowest quantized level, it will not send its local sensing data in the corresponding sensing period. The fusion center can implcitly know that a spectific CR node sensed lowest level if there is no report from that CR node. The goal of proposed sensing policy is to reduce the overhead of quantized data fusion scheme for cooperative sensing. Also, our scheme can be adapted to all quantized data fusion schemes because it only deal with the form of the quantized data report. The experimental results show that the proposed scheme improves performance in terms of reporting overhead.

• 한국광학회지
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• 제16권4호
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• pp.366-375
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• 2005

Ti 확산 리튬나오베이트 채널 광도파로의 z-축 분극을 주기적으로 $180^{\circ}$ 위상 변화시키는 Ti:PPLN 제작 공정을 검토하고, 개선하였다. 분극반전 공정에 적합한 지그와 Labview 프로그램을 이용하여 전하량 제어시스템을 고안하였다. 분극반전에 필요한 전하량으로부터 분극에 적절한 고전압 펄스와 duty-cycle을 조절하였으며, 분극에 필요한 임계 전압 보다 작은 전압을 인가한 상태에서 누설전류의 변화를 관찰하여 절연파괴 현상을 또한 최소화하였다.

• 대한화학회지
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• 제56권2호
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• pp.195-200
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• 2012

In this study we present a new approach for computing the partial atomic charge derived from the wavefunctions of molecules. This charge, which we call the "y_charge", was calculated by taking into account the energy level and orbital populations in each molecular orbital (MO). The charge calculations were performed in the software, which was developed by us, developed using the C# programming language. Partial atomic charges cannot be calculated directly from quantum mechanics. According to a partitioning function, the electron density of constituent molecular atoms depends on the electrostatic attraction field of the nucleus. Taking into account the Boltzmann population of each MO as a function of its energy and temperature we obtain a formula of partial charges.