• 한국수자원학회논문집
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• 제51권11호
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• pp.1031-1041
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• 2018

본 연구에서는 ANFIS 기반 GloSea5 앙상블 기상전망 개선 기법을 개발하고 평가하였다. 대상유역은 국내 주요 다목적댐인 충주댐 유역을 선정하였으며, 개선 기법은 ANFIS 기반의 전 후처리기법으로 구성된다. 전처리 기법에서 GloSea5의 앙상블 멤버에 가중치를 부여하며(OWM), 후처리 과정에서는 전처리결과를 편의보정 한다(MOS). 평가결과 편의보정된 GloSea5에 비해 예측성능이 개선되었으며, CASE3, CASE1, CASE2 순으로 모의성능이 우수하였다. 전처리 기법은 강수의 변동성이 큰 계절에 개선효과가 우수하였으며, 후처리 기법은 전처리로 개선하지 못한 오차를 줄 일 수 있는 것으로 나타났다. 따라서 본 연구에서 개발한 ANFIS 기반 GloSea5 앙상블 기상전망 개선 기법은 전 후처리 기법을 함께 사용하는 것이 가장 좋으며, 특히 여름철과 같이 강수의 변동성이 큰 계절에 활용성이 높을 것으로 판단된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.319-322
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• 2001

The proposed system was composed of pre-processor which was executing binary/high-pass filtering and post-processor which ranged from statistic data to prediction. In post-processor work, step one was filter process of image, step two was image recognition, and step three was destruction degree/time prediction. After these processing, we could predict image of the last destruction timestamp. This research was produced variation value according to growth of tree pattern. This result showed improved correction, when this research was applied image Processing. Pre-processing step of original image had good result binary work after high pass- filter execution. In the case of using partial discharge of the image, our research could predict the last destruction timestamp. By means of experimental data, this Prediction system was acquired ${\pm}$3.2% error range.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.206-211
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• 2021

Internet users are increasingly invited to express their opinions on various subjects in social networks, e-commerce sites, news sites, forums, etc. Much of this information, which describes feelings, becomes the subject of study in several areas of research such as: "Sensing opinions and analyzing feelings". It is the process of identifying the polarity of the feelings held in the opinions found in the interactions of Internet users on the web and classifying them as positive, negative, or neutral. In this article, we suggest the implementation of a sentiment analysis tool that has the role of detecting the polarity of opinions from people about COVID-19 extracted from social media (tweeter) in the Arabic language and to know the impact of the pre-processing phase on the opinions classification. The results show gaps in this area of research, first of all, the lack of resources when collecting data. Second, Arabic language is more complexes in pre-processing step, especially the dialects in the pre-treatment phase. But ultimately the results obtained are promising.

• 한국전기전자재료학회논문지
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• 제14권1호
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• pp.26-33
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• 2001

The proposed system was composed of pre-processor which was executing binary/high-pass filtering and post-processor which ranged from statistic data to prediction. In post-processor work, step one was filter process of image, step two was image recognition, and step three was destruction degree/time prediction. After these processing, we could predict image of the last destruction timestamp. This research was produced variation value according to growth of tree pattern. This result showed improved correction, when this research was applied image Processing. Pre-processing step of original image had good result binary work after high pas- filter execution. In the case of using partial discharge of the image, our research could predict the last destruction timestamp. By means of experimental data, this prediction system was acquired $\pm$3.2% error range.

• 대한전자공학회논문지SD
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• 제39권5호
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• pp.74-86
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• 2002

본 논문은 결정 궤환 구조를 갖는 차동 위상 검출기의 고속 데이터 처리를 위한 VLSI 구조를 제안한다. 기존 차동 위상 검출 방식의 낮은 BER 성능을 극복하기 위해 DF-DPD, DPD-RGPR, DFDPD-SA 등의 다중 심볼 검출 방식이 제시되었다. 이러한 검출 방식들은 참조 위상으로 사용되는 이전 심볼에서의 잡음 효과를 작게 하기 위하여 검출된 위상을 궤환시키는 구조를 갖고 있다. 하지만, 검출된 위상을 궤환시키는 작용은 데이터 처리 속도를 기존의 차동 위상 검출기보다 느리게 한다. 본 논문에서는 결정 궤환 구조를 갖는 차동 위상 검출기가 기존의 차동 위상 검출 방식처럼 고속으로 데이터를 처리할 수 있는 VLSI 구조를 제안하였다. 제안된 구조는 'M-1' 번째 과정에서 'M' 번째 과정을 미리 계산하는 선계산(pre-calculation) 방식과 'M-1'번째 과정에서 예견 위상들을 궤환시키는 선결정 궤환(pre-decision feedback) 방식을 갖는다. 본 논문에서 제안된 구조는 VHDL(Very-high-speed-IC Hardware Description Language)를 사용하여 RTL(Register Transfer Level)로 구현되었다. 시뮬레이션 결과, 제안된 구조는 고속으로 데이터를 처리함을 확인하였다.

• 대한임베디드공학회논문지
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• 제11권5호
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• pp.277-285
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• 2016

Moving object detection system has been an emerging research field in various advanced driver assistance systems (ADAS) and surveillance system. In this paper, we propose two optical flow based moving object detection methods at dynamic scenes. Both proposed methods consist of three successive steps; pre-processing, foreground segmentation, and post-processing steps. Two proposed methods have the same pre-processing and post-processing steps, but different foreground segmentation step. Pre-processing calculates mainly optical flow map of which each pixel has the amplitude of motion vector. Dense optical flows are estimated by using Farneback technique, and the amplitude of the motion normalized into the range from 0 to 255 is assigned to each pixel of optical flow map. In the foreground segmentation step, moving object and background are classified by using the optical flow map. Here, we proposed two algorithms. One is Gaussian mixture model (GMM) based background subtraction, which is applied on optical map. Another is adaptive thresholding based foreground segmentation, which classifies each pixel into object and background by updating threshold value column by column. Through the simulations, we show that both optical flow based methods can achieve good enough object detection performances in dynamic scenes.

• KCI Concrete Journal
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• 제12권2호
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• pp.3-10
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• 2000

A computer program, named NEO-PCBRG, for the analysis and design of prestressed con-crete(PSC) bridges was developed using the finite element method. NEO-PCBRG can predict the response of PSC bridges throughout the various stages of construction and service. NEO-PCBRG has both pre- and post-processing capabilities. Pre-processing refers to all the neces- sary steps required to prepare a virtual prototype, more commonly termed a varied model for analysis. Post-processing here stands for the step in which the results from the analysis are reviewed and interpreted. In order to allow for the easy and convenient execution of the entire procedure, NEO-PCBRG was developed using computer graphics in the Visual Basic pro- gramming language. In conclusion, this study presents a new software architecture for analy-sis using the user-oriented design technique.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2006년도 공동학술대회 논문집
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• pp.253-258
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• 2006

한반도는 고도의 산업화와 도시화로 인해 깨끗한 MT 및 GDS 자료를 획득하기 매우 어렵다. 이러한 환경에서는 적당한 신호 대 잡음비를 가지는 자료를 선별하는 전처리 과정이 필수적이다. 본 연구에서는 전자기장의 분광에너지에 기반한 자동 전처리 과정(RMP)을 한반도의 현실적인 상황을 고려하여 수정하였고, 이를 한반도 내륙에서 획득된 총 7 측점의 MT 자료에 적용하였다. 전반적으로, RMP 기법은 주기 10초 대역 부근에서 주파수에 따른 전기비저항과 위상의 연결성을 상당히 향상시켰다. 또한 RMP 기법에 의한 결과는 수작업으로 편집된 기존의 처리 결과와도 거의 유사였고, 특히 전기 비저항의 연결성면에서 그 우수성이 확인되었다.

• 한국위성정보통신학회논문지
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• 제11권2호
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• pp.14-17
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• 2016

본 논문은 시각 장애인들을 위해 영상처리 기반의 숫자-자동 점자 변환기의 설계 및 구현에 관한 내용을 기술한다. 영상처리 기반의 숫자-점자 변환 알고리즘은 카메라로 획득한 입력 영상을 이진 영상화 한 다음, 문자 영역을 팽창과 라벨링 연산을 수행하고 저장되어 있는 문자 패턴 영상과 상호 상관도를 계산하여 해당되는 점자로 변환한다. 컴퓨터 시뮬레이션을 통하여 제안한 알고리즘을 모의실험한 결과, A4 용지에 인쇄된 숫자(0-9)에 대하여 91.8% 변환 성공률을 보여 주었고, DSP 영상처리 보드에 구현한 시제품 시험을 통하여 90% 변환 성능을 확인함으로서 구현된 숫자-자동 점자 변환기의 실용화 가능성을 확인하였다.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.335-346
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• 2010

The present study investigates the difficulty of solving the mathematical problem, namely the DLP (Discrete Logarithm Problem) for ephemeral keys. The DLP is the basis for many public key cryptosystems. The ephemeral keys are used in such systems to ensure security. The DLP defined on a prime field $Z^*_p of random prime is considered in the present study. The most effective method to solve the DLP is the ICM (Index Calculus Method). In the present study, an efficient way of computing the DLP for ephemeral keys by using a new variant of the ICM when the factors of p-1 are known and small is proposed. The ICM has two steps, a pre-computation and an individual logarithm computation. The pre-computation step is to compute the logarithms of a subset of a group and the individual logarithm step is to find the DLP using the precomputed logarithms. Since the ephemeral keys are dynamic and change for every session, once the logarithms of a subset of a group are known, the DLP for the ephemeral key can be obtained using the individual logarithm step. Therefore, an efficient way of solving the individual logarithm step based on the newly proposed precomputation method is presented and the performance is analyzed using a comprehensive set of experiments. The ephemeral keys are also solved by using other methods, which are efficient on random primes, such as the Pohlig-Hellman method, the Van Oorschot method and the traditional individual logarithm step. The results are compared with the newly proposed individual logarithm step of the ICM. Also, the DLP of ephemeral keys used in a popular password key exchange protocol known as Chang and Chang are computed and reported to launch key recovery attack.