• 한국정보통신학회논문지
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• 제22권2호
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• pp.276-283
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• 2018

기후변화 등으로 해안 침수 등의 피해가 증가하고 있으며, 이러한 피해를 줄이기 위해 해양을 지속적으로 모니터링하기 위한 연구들이 진행되고 있다. 본 논문에서는 해수면의 변화를 모니터링하고 위험한 상황을 경보하는 해양모니터링 시스템에 적용할 수 있는 조위 예측 모델을 제안한다. 기존의 조위 예측 모델은 장기적인 예보를 위한 것으로 많은 데이터와 복잡한 알고리즘이 필요하기 때문에 실시간 시스템에는 적절하지 않다. 반면, 제안하는 알고리즘은 조위 센서에 의해 측정된 데이터를 이용하여 실시간으로 조위를 예측하는 방법으로 간단하지만 정확하게 한 시간 또는 두 시간의 비교적 짧은 시간 후의 조위를 예측한다. 제안하는 방법은 조석의 조화분석을 위해 칼만필터 알고리즘을 사용하고 추가적인 오류 보정을 위해 이중 지수 평활법을 사용한다. 실험 결과는 제안하는 알고리즘이 간단하지만 정확하게 조위를 예측하는 것을 보여준다.

• 센서학회지
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• 제15권6호
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• pp.433-441
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• 2006

Because of the low power and low rate of a sensor network, outlier is frequently occurred in the time series data of sensor network. In this paper, we suggest periodic pattern analysis that is applied to the time series data of sensor network and predict outlier that exist in the time series data of sensor network. A periodic pattern is minimum period of time in which trend of values in data is appeared continuous and repeated. In this paper, a quantization and smoothing is applied to the time series data in order to analyze the periodic pattern and the fluctuation of each adjacent value in the smoothed data is measured to be modified to a simple data. Then, the periodic pattern is abstracted from the modified simple data, and the time series data is restructured according to the periods to produce periodic pattern data. In the experiment, the machine learning is applied to the periodic pattern data to predict outlier to see the results. The characteristics of analysis of the periodic pattern in this paper is not analyzing the periods according to the size of value of data but to analyze time periods according to the fluctuation of the value of data. Therefore analysis of periodic pattern is robust to outlier. Also it is possible to express values of time attribute as values in time period by restructuring the time series data into periodic pattern. Thus, it is possible to use time attribute even in the general machine learning algorithm in which the time series data is not possible to be learned.

• 응용통계연구
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• 제7권1호
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• pp.149-158
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• 1994

커널 추정은 커널함수와 bandwidth에 의해서 결정이 된다. 그러나 평활의 정도를 조절하는 적절한 bandwidth를 찾는 것이 더욱 중요한 문제이다. 그러므로 이론적으로 최적의 bandwidth와 비교하여 실제자료에 잘 적용될 수 있는 적절한 bandwidth를 어떻게 찾느냐는 것이 문제가 된다. 본 논문에서는 평균제곱오차(mean square error)의 편의(bias)와 분산(variance)의 관계를 통하여 커널을 이용한 회귀선의 추정에 있어서 간단하고 효과적인 local bandwidth를 찾을 수 있는 알고리즘을 제안하였다.

• 복식
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• 제38권
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• pp.245-260
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• 1998

Our country's fur clothing industry has rapidly grown for a short time since it started with simple needlework of fur pieces, and now it is still developing as export industry that some enterprises besides general business firm export more than ten million dollars a year. However, it is true that fur clothing industry is still in unsatisfactory level in its size and system, compared with manufacturing or leather industry. Of course, we import crude material and processed fur on an entire base, and we have few wild fur on an entire base, and we have few wild fur animals because of our natural condition and it is hard to breed them. On the other hand, the world's fur industry shows that the demand of fur clothes is increasing as fur animal breeding is improved and developed and supply has become rather abundant with the help of fur clothing fashion since late 19th century : Also, there is a trend that some developed countries depend on importing rather than self-prodoction because of the character-istic of labor-concetntraled fur industry. Accordingly, considering this situation, we can expect fur clothing industry as promising export industry by analyzing the present situation of our country's fur clothing industry and suggesting its problems and solutions, and here are developing plans for growing fur clothing industry as promising export industry. First, smoothing delivery of crude material. Second, making high quality products and diversifying goods. Third, establishing effective competition system in fur clothing industry. Fourth, raising skilled man power. Lastly, there should be coopetation among the related fields in the aspect of policy including the support from the government.

• Smart Structures and Systems
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• 제14권4호
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• pp.569-594
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• 2014

Damage detection methods based on modal analysis have been widely studied in recent years. However the calculation of mode shapes in real structures can be time consuming and often requires dedicated software programmes. In the present paper the combined application of proper orthogonal decomposition and gapped smoothing method to structural damage detection is presented. The first is used to calculate the dynamic shapes of a damaged structural element using only the time response of the system while the second is used to derive a reference baseline to which compare the data coming from the damaged structure. Experimental verification is provided for a beam case while numerical analyses are conducted on plates. The introduction of a stiffener on a plate is investigated and a method to distinguish its influence from that of a defect is presented. Results highlight that the derivatives of the proper orthogonal modes are more effective damage indices than the modes themselves and that they can be used in damage detection when only data from the damaged structure are available. Furthermore the stiffened plate case shows how the simple use of the curvature is not sufficient when analysing complex components. The combined application of the two techniques provides a possible improvement in damage detection of typical aeronautical structures.

• 대한원격탐사학회지
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• 제36권4호
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• pp.503-513
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• 2020

This paper presents a method to evaluate denoising filters based on edge locations in their denoised images. Image quality assessment has often been performed by using structural similarity (SSIM). However, SSIM does not provide clearly the geometric accuracy of features in denoised images. Thus, in this paper, a method to localize edge locations with subpixel accuracy based on adaptive weighting of gradients is used for obtaining the subpixel locations of edges in ground truth image, noisy images, and denoised images. Then, this paper proposes a method to evaluate the geometric accuracy of edge locations based on root mean squares error (RMSE) and jaggedness with reference to ground truth locations. Jaggedness is a measure proposed in this study to measure the stability of the distribution of edge locations. Tested denoising filters are anisotropic diffusion (AF), bilateral filter, guided filter, weighted guided filter, weighted mean of patches filter, and smoothing filter (SF). SF is a simple filter that smooths images by applying a Gaussian blurring to a noisy image. Experiments were performed with a set of simulated images and natural images. The experimental results show that AF and SF recovered edge locations more accurately than the other tested filters in terms of SSIM, RMSE, and jaggedness and that SF produced better results than AF in terms of jaggedness.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.529-534
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• 2008

Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Tracer gas techniques are widely used to measure ventilation rates, ventilation effectiveness, and interzonal air movements. Depending on the number of gases used, they are divided into single and multi tracer gas methods. This paper deals with the comparison of the tracer gas methods in measuring air exchange rate between rooms. Experiments have been conducted in a simple two-room model with known airflow rates. In multi-gas procedure, the concentration decays of two tracer gases, i.e SF6 and R134a are measured after simultaneous injections in each room. The single tracer gas method is also applied by injecting SF6 gas with a time lag between two rooms. The data reduction procedures are developed to obtain the interzonal airflow rate using the matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, and smoothing. Uncertainty for each airflow rate is investigated depending on the parameters based on the setting values.

• 융합보안논문지
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• 제11권3호
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• pp.19-24
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• 2011

소프트웨어 고장 시간은 테스팅 시간과 관계없이 일정하거나, 단조증가 혹은 단조 감소 추세를 가지고 있다. 이러한 소프트웨어 신뢰모형들을 분석하기 위한 자료척도로 자료에 대한 추세 검정이 개발되어 있다. 추세 분석에는 산술평균 검정과 라플라스 추세 검정 등이 있다. 추세분석들은 전체적인 자료의 개요의 정보만 제공한다. 본 논문에서는 고장시간을 측정하다가 시간 절단이 될 경우에 미래의 고장 시간 예측에 관하여 연구 하였다. 시계열 분석에 이용되는 단순이동 평균법과 가중이동평균법, 지수평활법을 이용하여 미래고장 시간을 예측하여 비교하고자 한다. 실증분석에서는 고장간격 자료를 이용하여 모형들에 대한 예측값을 평균자승오차를 이용하여 비교하고 효율적 모형을 선택 하였다.

• 설비공학논문집
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• 제21권11호
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• pp.606-612
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• 2009

Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Tracer gas techniques are widely used to measure ventilation rates, ventilation effectiveness, and interzonal air movements. Depending on the number of gases used, they are divided into single and multi tracer gas methods. This paper deals with the comparison of the tracer gas methods in measuring air exchange rate between rooms. Experiments have been conducted in a simple two-room model with known airflow rates. In multi-gas procedure, the concentration decays of two tracer gases, i.e SF6 and R134a are measured after simultaneous injections in each room. The single tracer gas method is also applied by injecting SF6 gas with a time lag between two rooms. The data reduction procedures are developed to obtain the interzonal airflow rate using the matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, and smoothing. Uncertainty for each airflow rate is investigated depending on the parameters based on the setting values.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.99-104
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• 2007

Tracer gas technique is widely used to measure the ventilation rates and/or ventilation effectiveness of building spaces. However, the conventional method using a single tracer gas can measure only outdoor air change rates in a single zone. This paper deals with the multi-gas tracer technique to measure air exchange rates between rooms. Interzonal air movements are important to characterize overall ventilation performance of complicated multi-zone buildings. Experiments are conducted in a simple two-room model with known airflow rates using tracer gases of SF6 and R134a. The concentration decays of two tracer gases are measured after simultaneous injections in each room. The governing equations are derived from the continuity and the mass balance of each room. The data reduction procedure are developed to obtain the inter-room airflow rates using the governing matrix inversion, and various data manipulation methods are tested, such as data shift, interpolation, smoothing, and etc, to improve the estimate and interpretation of the results.