• 대한전자공학회논문지
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• 제27권2호
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• pp.65-72
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• 1990

이 논문에서는 인쇄체 한글문자 인식에 있어서 신경회로망의 적용가능성을 알아 보았다. 한글 문자수의 과다와 그들 사이의 유사성, 많은 입력 영상 데이타 등으로 인하여 신경회로망을 한글인식에 적용시키는데는 많은 난점이 따른다. 한글 문자의 이진영상은 신경회로망의 입력으로 사용하기에는 그 데이타 수가 너무 많으므로 입력 영상으로부터 DC 성분을 추출하여 이것을 신경회로망의 입력으로 사용하기 위한 전처리과정을 두었다. 출력층은 한글의 특성에 맞도록 구성하였다. 한글인식에 도입된 신경회로망은 다층인식자이고, 적용된 훈련방법은 BEP 알고리듬을 한글인식에 적절하도록 변형시킨 형태이다. 이 방법을 통하여 정위치에 있는 2,300개 이상의 문자를 인식할 수 있었다. 이 결과로부터 신경회로망을 이용한 인쇄체 한글문자 인식은 적절한 방법임을 알 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.900-904
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• 1991

In this paper, our study for the recognition of Hand-written Korean characters, Arabic numbers and alphabets by neural netwoks. This System extracts feature of character by using the MESH feature point of handwritten character, Arabic numbers and alphabets. To reduce the input image data, features are extracted from each input images. A MLP(multi-layer perceptron) with one hidden layer was trained with a modified BEP(back error propagation) algorithm. This method extracts feature sets of the characters directly from the scanner and can enhance computation speed without using the special preprocesses such as size normalization, smoothing, and thinning.

• 한국통신학회논문지
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• 제35권7A호
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• pp.731-742
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• 2010

We propose an incremental relaying protocol in conjunction with opportunistic communication for differential modulation with an aim to make efficient use of the degrees of freedom of the channels by exploiting a imited feedback signal from the destination. In particular, whenever the direct link from the source to the destination is not favorable to decoding, the destination will request the help from the opportunistic relay (if any). The performance of the proposed system is derived in terms of average bit error probability and achievable spectral efficiency. The analytic results show that the system assisted by the opportunistic relaying can achieve full diversity at low SNR regime and exhibits a 30㏈ gain relative to direct transmission, assuming single-antenna terminals. We also determine the effect of power allocation on the bit error probability BEP) performance of our relaying scheme. We conclude with a discussion on the relationship between the given thresholds and channel resource savings. Monte-Carlo simulations are performed to verify the analysis.

• ETRI Journal
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• 제25권4호
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• pp.231-237
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• 2003

We derive and analyze the exact closed-form expression for the average bit error probability (BEP) of M-ary square quadrature amplitude modulation (QAM) for diversity reception in frequency-nonselective Nakagami fading. A maximal ratio combining (MRC) diversity technique with independent or correlated fading cases are considered. Numerical results demonstrate error performance improvement with the use of MRC diversity reception. The presented new expressions offer a convenient way to evaluate the performance of M-ary square QAM with an MRC diversity combiner for various cases of practical interest.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.368-373
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• 2001

A major concern on high-energy centrifugal pump is the potential for interaction of two-phase flow phenomena with mechanical response of the pumping elements. The other concern is the pressure pulsations created from trailing edge of the impeller blade and flow separation and recirculation at partial load in centrifugal pumps. These interactions generating between rotor and casing cause dynamic pulsation on pump and exciting pipeline vibration. The higher severity responses, the more lead to failure of pump and system components. Finally, it cause severe axial vibration of single stage pump due to the hydraulic instability in flow condition below BEP.

• Structural Engineering and Mechanics
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• 제51권2호
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• pp.299-313
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• 2014

In the first part of this paper, the influences of some of crack parameters on natural frequencies of a cracked cantilever Functionally Graded Beam (FGB) are studied. A cantilever beam is modeled using Finite Element Method (FEM) and its natural frequencies are obtained for different conditions of cracks. Then effect of variation of depth and location of cracks on natural frequencies of FGB with single and multiple cracks are investigated. In the second part, two Multi-Layer Feed Forward (MLFF) Artificial Neural Networks (ANNs) are designed for prediction of FGB's Cracks' location and depth. Particle Swarm Optimization (PSO) and Back-Error Propagation (BEP) algorithms are applied for training ANNs. The accuracy of two training methods' results are investigated.

• 한국시뮬레이션학회논문지
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• 제9권1호
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• pp.11-19
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• 2000

The main idea behind the Intelligent Networks (IN) concept is the separation of switching function from the service control, in order to meet various service requirements of subscribers and development of new services in time. The (N+l) architecture of the IN service system consists of front-end processors (FEP) and back-end processors (BEP), which is in service in a domestic telecommunication company, and balances the traffic load for services among the processors. Under this architecture, the IN service system can distribute the traffic load dynamically, and M services are easily launched and manipulated minimizing impacts on the existing services. This paper traces the performance of the (N＋1) structured system by means of the simulation approach, and shed a light on the result.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.354-354
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• 2000

In this paper, we would study the applicability of neural networks to the recognition process of Korean stenographic character image, applying the classification function, which is the greatest merit of those of neural networks applied to the various pans so far, to the stenographic character recognition, relatively simple classification work. Korean stenographic recognition algorithms, which recognize the characters by using some methods, have a quantitative problem that despite the simplicity of the structure, a lot of basic characters are impossible to classify into a type. They also have qualitative one that it is not easy to classify characters for the delicacy of the character forms. Even though this is the result of experiment under the limited environment of the basic characters, this shows the possibility that the stenographic characters can be recognized effectively by neural network system. In this system, we got 90.86% recognition rate as an average.

• Journal of Communications and Networks
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• 제9권2호
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• pp.177-184
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• 2007

Alamouti space-time code (STC) is a part of the UMTS-WCDMA standard. However, up to the best of our knowledge no exact closed-form outage and bit error probability (BEP) formulas for this famous code exists. Evaluating its performance through simulations is time-consuming and therefore, there should be analytical performance graphs to serve as a reference which are derived in this paper for coherently MPSK-modulated data. Additionally, analytical results take into account different channel fading levels from transmit antennas to receive ones.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.101-102
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• 1998

1991년 Anderson 등이 높은 산소/질소 선택도를 갖는 분리막에 관한 발표를 한 이후, 많은 연구자들은 같은 결과를 재연하기 위한 연구와 함께 산소의 투과도를 향상시키기 위한 연구를 행하여 왔다. 그들은 HCl과 NaOH로 도핑, 탈도핑, 재도핑한 폴리아닐린막이 산소/질소의 선택도가 30에 가까운, 대단히 높은 값을 갖는다고 보고하였다. 한편 막의 성능을 향상시키기 위해 dodecylbenzenesulfonic acid와 같이 분자크기가 큰 도판트를 사용하려는 시도가 있었지만, 이에 따른 선택도의 감소 때문에 좋은 결과를 얻지는 못하였다. Pron등은 bis(2-ethyl hexyl) hydrogen phosphate(BEP)로 도핑된 폴리아닐린이 일반적인 유기용매에 잘 녹고, 여기에 PMMA나 ABS를 블렌드한 폴리아닐린은 높은 전도성과 기계적인 물성을 가질 수 있다고 하였다. Bis(2-ethyl hexyl) hydrogen phosphate는 mp가 -60$\circ$C정도 이며, 폴리아닐린 용액에 첨가하였을 때 상분리가 일어나지 않는 특성을 지닌 가소제이다.