• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.319-323
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• 2003

In this paper, we propose a hybrid transceiver for underwater acoustic communication, which allows the system to reduce complexity and increase robustness in time variant underwater channel environments. It is designed in the digital domain except for amplifiers and implemented by using a multiple digital signal processors (DSPs) system. The digital modulation technique is quadrature phase shift keying (QPSK) and frame synchronization is an energy (non-coherent) detection scheme based on the quadrature receiver structure. DSP implementation is based on block data parallel architecture (BDPA). We shaw experimental results in th? underwater anechoic basin at KRISO. The results indicate that the frame synchronization is performed without PLL. Also, we shaw that the adaptive equalizer can compensate frame synchronization error and the correction capability is dependent on the length of equalizer.

• 대한산업공학회지
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• 제36권2호
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• pp.125-137
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• 2010

This study focuses on the problem of scheduling wafer lots of several product families in the deposition workstation in a semiconductor wafer fabrication facility. There are multiple identical parallel machines in the deposition workstation, and two types of setups, record-dependent setup and family setup, may be required at the deposition machines. A record-dependent setup is needed to find optimal operational conditions for a wafer lot on a machine, and a family setup is needed between processings of different families. We suggest two-phase heuristic algorithms in which a priority-rule-based scheduling algorithm is used to generate an initial schedule in the first phase and the schedule is improved in the second phase. Results of computational tests on randomly generated test problems show that the suggested algorithms outperform a scheduling method used in a real manufacturing system in terms of the sum of weighted flowtimes of the wafer lots.

• 한국지능시스템학회논문지
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• 제10권4호
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• pp.315-323
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• 2000

본 논문에서는 생명창발과 진화에 기반한 신경망 구성방법을 제안한다. 이 방법은 생뭉의 DNA 구조의 특성과 식물의 생장에 기반을 둔 방법이다. 본 논문에서 제안한 방법은 DNA 코딩 방법과 L-system의 생장 구칙을 이용하여 신경망을 구성하는 방법이닫. L-system은 병렬적인 제조합 규칙을 이용하여, DNA 코딩 방법은 표현의 제약이 없는 표기법이다. 또한 진화 알고리듬은 다윈의 자연도태를 모방한 탐색법으로 다양한 해공간의 표현과 높은 효율로 탐색이 가능하다. 본 논문에서는 이러한 방법들을 이용햐 신경망을 구성하고, 신경망의 Mackey-Glass, Sunspot, KOSPI 같은 시계열 예측분제에 적용하여 유효성을 입증하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4930-4951
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• 2018

The deep learning based speech enhancement has shown considerable success. However, it still suffers performance degradation under mismatch conditions. In this paper, an adaptation method is proposed to improve the performance under noise mismatch conditions. Firstly, we advise a noise aware training by supplying identity vectors (i-vectors) as parallel input features to adapt deep neural network (DNN) acoustic models with the target noise. Secondly, given a small amount of adaptation data, the noise-dependent DNN is obtained by using $L_2$ regularization from a noise-independent DNN, and forcing the estimated masks to be close to the unadapted condition. Finally, experiments were carried out on different noise and SNR conditions, and the proposed method has achieved significantly 0.1%-9.6% benefits of STOI, and provided consistent improvement in PESQ and segSNR against the baseline systems.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.115-120
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• 1997

We have developed new algorithms for solution of the three-dimensional, time-dependent Navier-Stokes equations that utilize massively parallel supercomputing implemented on the Connection Machine 5. Here, we apply these techniques to analyze he fluid flows that occur during the growth of the tow nonlinear optical crystals-potassium dihydrogen phosphate (KDP), which is producted in a novel rapid growth system under development by the Lawrence Livermore National Laboratory Laser Division, and Potassium titanyl phosphate(KTP), which is grown from a high-temperature aqueous solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.139-139
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• 2009

As ideal new energy, solar cell has renewable and inexhaustible characteristics and the fuel cell only needs low maintenance and low operating cost. This paper introduces hybrid system of solar cell and fuel cell considering the advantages of stable and sustainable energy from the economic point of view. Then the paper shows the I-V characteristics of the solar module which are dependent on the power of the halogen lamp and the P-I and I-V characteristics of fuel cells which are connected in parallel and series.

• 한국환경과학회지
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• 제9권5호
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• pp.389-392
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• 2000

In this study a packed tower was selected for the treatment apparatus of $NH_3$ gas produced in industry. Formerly latticework packing has been used in preventive facility of treatment of $NH_3$ gas. However recently metallic Ralu-Pack 250YC. structured packing is usually being used in petrochemical production plant. This study is for the application the packing to the $NH_3$ gas treatment in wet scrubbing process. In Air/water system hydraulic pressure drop dependent of specific liquid load and gas capacity factor was continuous and parallel from graph. The tower height can be determuined by the number of transfer unit and the height of transfer unit influenced on liquid distribution.

• 품질경영학회지
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• 제11권2호
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• pp.32-36
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• 1983

지금까지의 신뢰도 분석 모형은 대부분이 한가지 유형의 고장상태를 가정하였다. 그러나, 현실적으로 고장상태를 몇가지 유형으로 나누는 것이 바람직할 경우가 많다. 예를들면, 어떤 스위치의 경우 닫혀야할 때 열리는 고장과 열려야할 때 닫히는 고장이 있을 것이다. 이러한 예는 자동화기계, 배수관, 폭발물 등에서 찾아볼 수 있다. 본 논문에서는 두가지 유형의 고장상태를 갖는 중복시스템(직렬구조, 병렬구조, 대기구조)에 관한 마아코프 분석 모형을 설정하고, 라플라스 변환법을 사용하여 가용도 함수를 구하였다.

• 한국통신학회논문지
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• 제21권7호
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• pp.1833-1841
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• 1996

Recently, by emerging of the ALE techniques that make it possible to providereliable communications link automatically, high frequency communiation is newly used as emergency communication and back-up for satellite communications. ALE signal is transmitted in burst, and the received signal is subject to distortions by detrimental multipath fading channels. In the case of that channel, the performance of ALE system is highly dependent upon that of synchronization techniques. In this paper, M-ary FSK signals are detected by a bank of bandpass filter, which is implemented using recusive DFT(Discrete Fourier Transform). Also an acquisition and trancking algorithm are designed uisng parallel structure and early-late-gate methods respectively. Finally, we verify the performance ofthe proposed synchronization algorithm by the computer simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.34-39
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• 1998

In order to compute the forces which are transmitted through rubber bushings with a commercial multibody dynamic analysis (MBDA) program, a rubber bushing model is needed. The rubber bushing model of MBDA programs such as DADS or ADAMS is the Voigt model which is simply a parallel spring-viscous damper system, meaning that the damping force of the Voigt model is proportional to the frequency. However, experiments do not necessarily support this proportionality. Alternatively, the viscoelastic characteristics of rubber bushings can be better represented by the complex stiffness. The purpose of this paper is to develop a viscoelastic rubber bushing model for the MBDA programs. Firstly, a methodology is proposed to calculate the complex stiffness of rubber bushings considering static and dynamic load conditions. Secondly, a viscoelastic rubber bushing model developed which uses standard elements provided by DADS. The proposed methods are applied to the rubber bushings of the lower control arms of a rear suspension of a 1994 Ford Taurus model. Then, the forces computed for the rubber bushing model are analyzed and compared with the Voigt model in time and frequency domains.