우리나라 해역별 해양환경에 최적화된 확률모형 개발

조용준 한국해안,해양공학회 2024 한국해안해양공학회 논문집 Vol.36 No.1

본 연구에서는 먼저 우리나라 해역별 해양환경 특성이 담긴 장기 파랑 관측자료로부터 Goda 모형을활용하여 파력과 양력 시계열자료를 생성하였다. 이어 이렇게 생성된 시계열자료부터 Three-parameter Weibull distribution에 기반한 파력과 양력 확률모형을 개발하였다. 해역별로 다른 우리나라 해양환경은 파력과 양력 확률모형 모수에서도 그 차이를 확연하게 드러내었다. 충분히 발달한 풍성 파가 우월한 남해안의 경우 큰 Scale Coefficient, 작은 Location Coefficient, 1.3 전후의 Shape Coefficient로 특정되는 것을 확인하였다. 이에 비해 파랑의성장이 취송거리에 의해 제한되는 서해를 마주하고 있는 군산의 경우 작은 Scale Coefficient, 큰 Location Coefficient, 2.0 전후의 Shape Coefficient로 특정되었다. 서해와 남해가 만나는 해역을 마주하고 있는 목포의 경우 작은 Scale Coefficient, 큰 Location Coefficient, 제일 작은 Shape Coefficient를 지녀 남해와 서해의 해양환경이 혼재한다는 사실도 확인할 수 있었다. In this study, probabilistic models for the wave- and lifting forces were derived directly from long term in-situ wave data embedding the Korean marine environment characteristics varying from sea to sea based on the Three-Parameter Weibull distribution. Korean marine environment characteristics varying from sea to sea carved out their presence on the probability coefficients of probabilistic models for wave- and lifting forces. Energetic wave conditions along the southern coast of Korea distinguish themselves from the others with a relatively large scale coefficient, small location coefficient, and shape coefficient around 1.3. On the other hand, mild marine environment along the western coast has a small variability, leading to small scale-coefficient, large location coefficient and shape coefficient around 2.0. In the sea off Mokpo, near the boundary between the South and West Seas, marine environment was characterized by small scale-coefficient, large location coefficient, and shape coefficient around 1.2, implying that marine environments characteristics of the South-and West Sea coexist in the sea off Mokpo.

Noncrossing varying coefficient support vector quantile regression

Jooyong Shim,Changha Hwang,Insuk Sohn,Kyungha Seok 한국데이터정보과학회 2020 한국데이터정보과학회지 Vol.31 No.6

Quantile regression fits specified percentiles of the response, such as the 90th percentile, and can potentially describe the entire conditional distribution of the response. Sometimes quantile functions estimated at different quantiles can cross each other. Varying coefficient models are a useful extension of classical linear models. We propose a new noncrossing varying coefficient support vector quantile regression method based on a location-scale model. To choose the hyper-parameters we apply the model selection method that use cross validation techniques. The proposed method provides a good solution for estimating noncrossing quantile regression functions when several quantiles are required. Real examples are provided to show the usefulness of the proposed method.

Development of Fault Location Algorithm and Its Verification Experiments for HVDC Submarine Cables

Chae-Kyun Jung,Hung-Sok Park,Ji-Won Kang,Xinheng Wang,Yong-Kab Kim,Jong-Beom Lee 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

A new fault location algorithm based on stationary wavelet transform and its verification experiment results are described for HVDC submarine cables in this paper. For wavelet based fault location algorithm, firstly, 4th level approximation coefficients decomposed by wavelet transform function are superimposed by correlation, then the distance to the fault point is calculated by time delay between the first incident signal and the second reflected signal. For the verification of this algorithm, the real experiments based on various fault conditions and return types of fault current are performed at HVDC submarine cable test yard located in KEPCO(Korea Electric Power Corporation) Power Testing Center of South Korea. It proves that the fault location method proposed in this paper is very simple but very quick and accurate for HVDC submarine cable fault location.

생활SOC의 지역 간 격차와 최적입지 분석 - 생활거점시설을 중심으로

이세영,김현중,여관현 한국측량학회 2022 한국측량학회지 Vol.40 No.3

Local governments should try to resolve the inequality of living SOC (Social Overhead Capital) and construct spatial information on the location of living SOCs and optimal locations. This study analyzed the accessibility, equity, and optimal location of the living SOC, considering the research needs related to the living SOC. The target facility is core living facilities(a public library, a park, a culture center, and a public daycare center). The analysis area is Suwon city in Gyeonggi province, and the base year of the analysis is 2020. The study calculated accessibility per population in a microscopic neighborhood living area(200m×200m). The Gini coefficient was used to identify the regional disparity in accessibility among Dong regions. The optimal location was explored with the Maximal Covering Location Problem theory. As a result, spatial accessibility of facilities except for public daycare centers revealed a large gap between regions. Areas with excellent accessibility also showed significant variations in the facilities. The regional disparity in living SOC was the largest in culture centers, followed by parks, public daycare centers, and public libraries. The optimal locations for public libraries, parks, and culture centers are concentrated in the old downtown, while those of public daycare centers are found throughout Suwon city. The results of this study are the crucial contents of spatial planning for SOC supply in local governments. Therefore, follow-up studies will be able to refer to the analysis structure and results of the study. 지방자치단체는 생활SOC의 불균형을 해소하려는 노력을 추진되어야 하며, 생활SOC의 입지 현황, 최적입지 등에 관한 공간정보를 구축해야 한다. 이 연구는 생활SOC 관련 연구수요를 고려하여, 생활SOC의 접근성, 형평성, 그리고 최적입지를 분석하였다. 분석 시설은 생활거점시설로서, 공공도서관, 근린공원, 생활문화센터, 국공립어린이집으로 구성하였다. 분석지역은 경기도 수원시이며, 분석의 기준연도는 2020년이다. 접근성은 세생활권(200m×200m)에서 인구 1인당 접근성을 산출하였다. 형평성은 지니계수를 활용하여 동 간 접근성의 지역 간 격차를 확인하였다. 최적입지는 최대 커버링 입지문제를 활용하여 탐색하였다. 분석 결과, 국공립어린이집을 제외한 시설의 공간적 접근성은 지역 간 커다란 차이를 드러냈다. 접근성이 우수한 지역도 시설에 따라 커다란 편차를 보였다. 생활SOC의 지역 간 격차는 생활문화센터가 가장 컸으며, 뒤를 이어, 근린공원, 국공립어린이집, 공공도서관 순으로 나타났다. 공공도서관, 근린공원, 생활문화센터의 최적입지는 원도심에 집중적으로 분포하였으나, 국공립어린이집의 최적입지는 수원시 전역에서 나타났다. 이 연구의 결과는 추후 지방자치단체에서 생활SOC 공급계획을 수립함에 있어 핵심적인 계획내용이다. 따라서 후속연구는 이 연구의 분석구조와 결과를 유용하게 활용 가능할 것으로 기대한다.

Development of Fault Location Algorithm and Its Verification Experiments for HVDC Submarine Cables

Jung, Chae-Kyun,Park, Hung-Sok,Kang, Ji-Won,Wang, Xinheng,Kim, Yong-Kab,Lee, Jong-Beom The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

A new fault location algorithm based on stationary wavelet transform and its verification experiment results are described for HVDC submarine cables in this paper. For wavelet based fault location algorithm, firstly, 4th level approximation coefficients decomposed by wavelet transform function are superimposed by correlation, then the distance to the fault point is calculated by time delay between the first incident signal and the second reflected signal. For the verification of this algorithm, the real experiments based on various fault conditions and return types of fault current are performed at HVDC submarine cable test yard located in KEPCO(Korea Electric Power Corporation) Power Testing Center of South Korea. It proves that the fault location method proposed in this paper is very simple but very quick and accurate for HVDC submarine cable fault location.

Location Template Matching(LTM) 방법에 사용되는 유사성 척도들의 비교 연구

신기홍(Kihong Shin) 한국소음진동공학회 2014 한국소음진동공학회 논문집 Vol.24 No.4

The location template matching(LTM) method is a technique of identifying an impact location on a structure, and requires a certain measure of similarity between two time signals. In general, the correlation coefficient is widely used as the measure of similarity, while the group delay based method is recently proposed to improve the accuracy of the impact localization. Another possible measure is the frequency response assurance criterion(FRAC), though this has not been applied yet. In this paper, these three different measures of similarity are examined comparatively by using experimental data in order to understand the properties of these measures of similarity. The comparative study shows that the correlation coefficient and the FRAC give almost the same information while the group delay based method gives the shape oriented information that is best suitable for the location template matching method.

위치모수를 이용한 로버스트 CV 관리도의 설계

전동진(Dong Jin Chun),정영배(Young Bae Chung) 한국산업경영시스템학회 2016 한국산업경영시스템학회지 Vol.39 No.1

Recently, the production cycle in manufacturing process has been getting shorter and different types of product have been produced in the same process line. In this case, the control chart using coefficient of variation would be applicable to the process. The theory that random variables are located in the three times distance of the deviation from mean value is applicable to the control chart that monitor the process in the manufacturing line, when the data of process are changed by the type of normal distribution. It is possible to apply to the control chart of coefficient of variation too. ??,  estimates that taken in the coefficient of variation have just used all of the data, but the upper control limit, center line and lower control limit have been settled by the effect of abnormal values, so this control chart could be in trouble of detection ability of the assignable value. The purpose of this study was to present the robust control chart than coefficient of variation control chart in the normal process. To perform this research, the location parameter, ????, ?? were used. The robust control chart was named Tim-CV control chart. The result of simulation were summarized as follows; First, P values, the probability to get away from control limit, in Trim-CV control chart were larger than CV control chart in the normal process. Second, ARL values, average run length, in Trim-CV control chart were smaller than CV control chart in the normal process. Particularly, the difference of performance of two control charts was so sure when the change of the process was getting to bigger. Therefore, the Trim-CV control chart proposed in this paper would be more efficient tool than CV control chart in small quantity batch production.

Location Template Matching (LTM) 방법에 사용되는 유사성 척도들의 비교 연구

신기홍(Kihong Shin) 한국소음진동공학회 2014 한국소음진동공학회 학술대회논문집 Vol.2014 No.4

The location template matching (LTM) method is a technique of identifying an impact location on a structure, and requires a certain measure of similarity between two time signals. In general, the correlation coefficient is widely used as the measure of similarity, while the group delay based method is recently proposed to improve the accuracy of the impact localization. Another possible measure is the frequency response assurance criterion (FRAC), though this has not been applied yet. In this paper, these three different measures of similarity are examined comparatively by using experimental data in order to understand the properties of these measures of similarity. The comparative study shows that the correlation coefficient and the FRAC give almost the same information while the group delay based method gives the shape oriented information that is best suitable for the location template matching method.

Location Template Matching(LTM) 방법을 적용함에 있어서 진동 모드 수의 영향

신기홍(Kihong Shin) 한국소음진동공학회 2016 한국소음진동공학회 논문집 Vol.26 No.2

The location template matching (LTM) method is a technique of identifying an impact location on a structure, and is often applied to structural health monitoring and large scale human-computer interface (HCI) systems. The LTM method utilizes a certain measure of similarity between two time signals. The correlation coefficient is most widely used for this purpose, and the group delay based method is recently proposed to improve the accuracy of finding the best matching pair of signals. In practice, one of key essential consideration for implementing the LTM method is to guarantee that a sufficient number of vibration modes must be contained in the measured signal, and yet the lower sampling rate is needed for a real-time implementation. In this paper, the properties of correlation coefficient and group delay with respect to the number of vibration modes are investigated. A few important results are obtained through extensive computer simulations and experiments. If the number of vibration modes contained in the measured signal is more than four it is sufficient for the correlation based LTM method, while the group delay based LTM method requires smaller number of vibration modes.

외팔 보를 이용한 Location Template Matching 방법을 적용함에 있어서 격자간격의 영향 분석

신기홍(Kihong Shin) 한국소음진동공학회 2016 한국소음진동공학회 논문집 Vol.26 No.5

Measuring similarity between two signals is a key element of the location template matching (LTM) method which is one of impact source localization technique. As a measure of similarity, the correlation coefficient is most widely used, and the group delay based method is recently proposed to improve the accuracy of finding the impact source. In practice, the LTM method assumes that the similarity between two signals decreases as the distance between two corresponding impact points increases, where the distance between two neighboring impact points defines the grid spacing. In this paper, it is shown that this assumption is not always true but the correlation coefficients fluctuate forming a main robe and many side robes as the distance between two neighboring impact points increases. On the other hand, the standard deviation of group delay sharply increases with a small increase of the grid spacing. These are demonstrated by using a simple cantilever beam. Based on these findings, an optimal way of implementing the LTM method may be suggested by combining the correlation coefficient and the group delay based approaches.