• Journal of Digital Convergence
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• v.12 no.8
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• pp.329-335
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• 2014

Collaborative filtering has been popular in commercial recommender systems, as it successfully implements social behavior of customers by suggesting items that might fit to the interests of a user. So far, most common method to find proper items for recommendation is by searching for similar users and consulting their ratings. This paper suggests a new similarity measure for movie recommendation that is based on genre interest, instead of differences between ratings made by two users as in previous similarity measures. From extensive experiments, the proposed measure is proved to perform significantly better than classic similarity measures in terms of both prediction and recommendation qualities.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.779-781
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• 2013

As the demand for various multimedia service increases the technology that utilizes image as information transfer method develops rapidly. Though average filter, median filter and weight filter etc. have been proposed to remove various noises that are added to images, the existing methods are short of noise removal and edge reservation performance. Therefore, in this paper an algorithm, in which noise is decided at the first hand, and then it is processed through modified median filter and adaptive weighted average filter, is proposed to effectively remove the complex noise that has been added to an image. And it was compared with existing methods through simulation and PSNR(peak signal to noise ratio) has been used as a criterion.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1292-1295
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• 2009

일반적으로 유역의 기저유출 산정에는 적용의 간편성을 이유로 수평직선분리법, N-day법등을 주로 사용해 왔으며 이를 단기호우사상에 대한 모의에 적용해 왔다. 그러나 수평직선분리법이나 N-day에의한 기저유량의 산출은 연구자의 주관성이 반영될 수 있는 가능성이 다분하며 총 유출에 대한 기저 유출의 기여가 상대적으로 크게 되는 장기유출모의에 이용하기에는 효율적이지 못할 뿐 아니라 분석을 수행하는 사람에 따라서 그 결과에 많은 차이가 있을 수 있다. 그래서 최근에는 이러한 문제를 해결하기 위해서 다양한 'Digital Filtering' 방법이 수문곡선 분리에 많이 사용되고 있다. Eckhardt 필터는 출력의 신호대 잡음비가 최소화를 목적함수로 사용하는 최적선형필터의 형태를 갖고 있으며, BFImax 변수 값을 이용하여 수문분석 시 대수층별 특성을 반영할 수 있는 장점을 지니고 있다. 따라서 BFImax 변수 값에 따라서 분리된 직접유출과 기저유출 값에는 상당한 차이가 발생할 수 있는데, 정확한 수문분석을 위해서는 연구대상 유역 내 대수층의 특성에 가장 부합되는 BFImax 변수 값을 구하여야 하는 어려움이 있다. 이러한 문제를 해결하기 위하여 감수곡선 분석방법과 최적화 기법을 이용하여 BFImax 변수 값을 결정해 주는 모듈을 사용하고 있다. 금강유역의 수문곡선분리를 위해 먼저 금강 유역 내 관측소의 강우 및 수위 일 자료를 수집하고 수위자료는 동향, 옥천, 천천, 청성, 호탄지점의 자료를 이용하였다. 관측단위는 일 단위를 사용하였다. 분리된 수문곡선에 대한 검증은 지하수관측이나 중간유출에 대한 관측에 한계가 있기 때문에 정량적인 검증은 쉽지 않은 상황이고 수문곡선에 대한 시각적 판단에 의지하고 있다. 하지만 효과적인 기저유출분리가 가능해진다면 하천 건천화에 대한 정확한 진단과 함께 기후변화에 따른 지하수 및 지표수 영향에 대한 보다 신뢰도 있는 전망이 가능해지므로 매우 중요한 연구 분야라 판단된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.408-414
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• 2009

A GPS/INS system is widely used in the UGV to estimate position during the mission. However, there are few restrictions when a GPS/INS system used alone. For example, GPS provides precise location information but easily interrupted by external factors like weather, environment, etc. INS provides continuous location data but positioning errors grew very rapidly with time. Therefore, it is necessary to integrating multi-sensors for more continuous and correct position estimation. In this paper, we propose location estimation algorithm of the UGV for GPS/INS integrated system that combines Fuzzy Inference and Unscented Particle Filter(UPF) to improve navigation. Fuzzy inference provides the simplest method integrating GPS/INS and UPF is non-linear estimation filter well suited to the correction of errors. The performance of the proposed algorithm was tested to compare with other algorithms. the results show that the proposed algorithm is more accuracy in position estimation and ensures continuous position tracking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1284-1289
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• 2016

Recently, digital image processing is applied a lot to the broadcasting, communication, computer graphic, and medical sectors. It generates noise when data is transmitted. There are many kinds of noises that add to the image such as salt and pepper noise, AWGN, and complex noise. Thus, this study divides the corrupted image into four4 areas and estimates the types of noises each pixel, and this study suggested a switching filter that separates the estimated into salt and pepper noise and AWGN. In the case that center pixel of local mask is corrupted by salt and pepper noise, it used a histogram probability weighting of subdivided area. Also, in case that it is corrupted by AWGN, algorithm that is applied to with different weights given for the distribution of each area with using subdivided area's distribution was suggested. For an objective comparison and conclusion, this study used PSNR and compared to existing methods.

• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.78-90
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• 2013

Recently, the interest on exposure to radiation is rising. The radiation exposure of mammography is higher in absorbed dose than of X-ray, therefore unnecessary exposure needs to be reduced, and higher image quality is needed. Generally, ray quality of the radiation imaging is an important factor that determines image quality and the amount of ray exposure, and they are affected by tube voltage and added filter. The X-ray energy that is exposed from mammography device is generally a continuous spectrum, which includes low energy that has minute influence on the image quality, and high energy that hinders contrast on image. Currently, molybdenum (Mo) and rhodium (Rh) are the most used added filters for mammography device, and they are used differently according to the energy region of X-ray. This study aims to find out the degree of reduction in exposure dose according to the thickness of aluminum (Al), and to study the changes in image quality and dose when the added filter plates that are made with niobium (Nb) or zirconium (Zr) are used, other than molybdenum (Mo) and rhodium (Rh), the two most used added filters that have similar atomic number and K-absorption regions as Nb and Zr. In this study, single-added filters of molybdenum (Mo), niobium (Nb), and zirconium (Zr) are used, and in some cases, Aluminum (Al) is combined with the single filters. In this case, image quality is considered to be improved depending on the type of added filters, and by using Aluminum (Al) filter together with the others, unnecessary X-ray of low energy would be absorbed, therefore the dose is expected to decrease without any influence when the concentration level becomes identical.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.168-171
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• 2003

화산석/polyurethane 복합담체를 충전한 biofilter에서 ethyl acetate의 제거특성에 관한 연구결과는 다음과 같다. 공탑접촉시간(EBCT)을 30 sec로 운전시에는 ethyl acetate의 유입농도가 300 ppmv 이하에서는 100%의 제거효율을 나타내었다. 유입부하량에 따른 제거용량을 살펴보면 유입부하량이 160 g/m3/hr 이하일때는 유입부햐량과 제거용량과는 직선적인 관계를 보였으며 본 연구에서 ethyl acetate의 최대제거용량은 210 g/m3/hr으로 산정되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.166-168
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• 2004

복합어 추출 기법은 최근 활발한 연구가 진행되고 있는 온톨로지 구축과 정보 검색에 중요한 기법으로 연구되어 왔다. 초기의 연구는 주로 언어학적인 필터 기법이나 통계적 기법을 사용하였지만, 최근 문맥정보와 의미 사전 등을 이용하여 용어를 추출하는 방법으로 발전해 오고 있다. 또한 정보검색 분야와 온톨로지 분야에서도 모든 용어를 추출하는 방법보다 문서 집합의 도메인에 적합하다고 판단되는 용어들을 추출하는 방법이 그 성능을 향상시킬 수 있다. 본 논문에서는 통계학적 방법을 이용하여 도메인에 적합한 시드 용어의 추출을 하고, 그 시드 용어를 이용해 가중치를 정제하는 방법과 시드 용어로부터 관련된 용어를 추출해 나가는 방법을 적용하여 문서 집합의 도메인에 맞는 용어들을 추출하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.629-635
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• 2017

In this paper, we proposed a nonlinear synthesis filter for noise reduction to reduce the effects of Gaussian noise and impulse noise. When the centralization of the local mask is judged to be Gaussian noise by the noise judgment, the weight value of the weight filter are applied differently according to the spatial weight filter and the pixel change by using the sample variance in the local mask. And if it is determined as the impulse noise, we proposed an algorithm that applies different weights of local histogram weight filter and standard median filter according to noise density of mask. In order to evaluate the performance of the proposed filter algorithm, we used PSNR(peak signal to noise ratio) and compared existing methods and proposed filter algorithm in the mixed noise environment with Gaussian noise, impulsive noise, and two noises mixed.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.569-570
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• 2016

본 논문은 뇌파 기반 감정 분류 기술의 상용화를 위한 낮은 성능을 보완하기 위하여 Regularized Common Spatial Pattern 필터링을 통한 전처리 방식을 제안하고 있다. RCSP 필터는 뇌파 기반 행동 인식 시스템에서 높은 성능 향상을 보이는 것으로 알려져 있다. 본 연구에서는 장기적이고 복합적인 뇌파의 감성 인지 연구에도 RCSP 필터의 적용 방법을 설명하고, 제안하는 알고리즘이 뇌파를 통한 감정 인식에 성능 향상을 보여준다는 것을 설명하고 있다.