• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.511-516
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• 2004

수치표고모델, 정사영상과 같은 공간영상정보를 구축하기 위해서는 입체영상을 이동한 영상정합(image matching)의 과정이 필수적이며, 단영상 또는 스테레오 영상을 이용하여 대상물의 3차원 정보를 재구성하고 복원하는 기술은 사진측량 및 컴퓨터 비전 분야의 주요 연구 중의 하나이다. 본 연구에서는 화소값의 유사성과 상호관계성을 고려하는 MRF 모델을 이용하여 영상정합을 수행하였다. MRF 모델은 공간분석이나 물리적 현상의 전후관계(contextural dependencies)의 분석을 위한 확률이론의 한 분야로 다양한 공간정보를 통합할 수 있는 방법을 제공한다. 본 연구에서는 기준영상의 화소에 시차를 할당하는 접근 방법으로 확률모델의 일종인 마르코프 랜덤필드(MRF)모델에 기반한 영상정합기법을 제안하였고, 공간내 화소의 상호관계를 고려해주므로 대상물의 경계부분에서의 매칭 정확도를 향상시켰다. 영상정합문제에서의 MRF 기본가정은 영상 내 특정화소의 시차는 그 주위화소의 시차에 의한 부분정보에 따라 결정이 가능하다는 것이다. 깁스분포(gibbs distribution)를 사용하여 사후(posteriori) 확률값을 유도해내고, 이를 최대사후확률(MAP: Maximum a Posteriori)추정법을 이용하여 에너지함수를 생성하였다. 생성된 에너지함수의 최적화(Optimization)를 위하여 본 연구에서는 전역최적화기법인 multiway cut 기법을 사용하여 영상정합에 있어 에너지함수를 최소로 하는 이미지화소에 대한 시차레이블을 구하여 영상정합을 수행하였다.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.939-947
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• 2019

With the revitalization of the media market, the necessity of compression, searching, editing and copyright protection of videos is increasing. In this paper, we propose a method to detect scene change in all these fields. We propose a pre-processing, feature point extraction using SIFT, and matching algorithm for detecting the same scene change even if distortions such as resolution change, subtitle insertion, compression, and flip are added in the distribution process. Also, it is applied to filtering technology and it is confirmed that it is effective for all transformations other than considering transform.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.798-807
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• 2021

The directivity characteristics of acoustic transducers for conventional single-beam echo sounders considerably limit the detection of fish-size information in acoustic field surveys. To overcome this limitation, using the split-aperture technique to estimate the direction of arrival of single-echo signals from individual fish distributed within the sound beam represents the most reliable method for fish-size classification. For this purpose, we design and develop a split-beam data acquisition and processing system to obtain fish-size information in conjunction with a 50-kHz single-beam echo sounder. This split-beam data acquisition and processing system consists of a notebook PC, a field-programmable gate array board, an external single-transmitter module with a matching network, and four-channel receiver modules operating at a frequency of 50-kHz. The functionality of the developed split-beam data processor is tested and evaluated. Acoustic measurements in an experimental water tank showed that the developed data acquisition and processing system can be used as a fish-sizing echo sounder to estimate the size distribution of individual fish, although an external single-transmitter module with a matching network is required.

• Journal of Distribution Science
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• v.15 no.7
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• pp.5-17
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• 2017

Purpose - This study analyzes an economic effect on the project that Korean government supported for the vitalization of traditional markets using an input-output model. From 2002 to 2013, the government provided 180.8 billion won for a Management Modernization Project and 2.851 trillion won for a Facility Modernization Project for vitalization of traditional markets. Research design, data, and methodology - The present study conducted inter-industry analysis by matching industries related to the Traditional Market Project for the measurement, and calculated the ripple effect of each project. Result - The results from the study showed that from 2002 to 2012, the Management Modernization Project and Facility Modernization Project showed a 296.1 billion won effect on production inducement, a 158.7 billion won value-added inducement effect, and a 3,135-person effect on employment inducement in total. From 2002 to 2013, the Facility Modernization Project showed a 6.948 trillion won effect on production inducement, a 2.1109 trillion won effect on value-added inducement, and 40,209-person of effect on employment inducement in total. Conclusions - This study provided an empirical demonstration of a clear effect of the governmental support to traditional markets on developing regional economies. In particular, this study empirically analyzed and presented that there were a considerable amount of an economic effect by region due to governmental policy support to traditional markets.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1683-1689
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• 2014

In this paper, we propose an image processing based time-frequency domain reflectometry(TFDR) in order to estimate the fault location of a cable. The Wigner-Ville distribution is used for analysis in both the time domain and the frequency domain when the conventional TFDR estimates the fault location in a cable. However, the Winger-Ville distribution is a bi-linear function, and hence the cross-term is occurred. The conventional TFDR cannot estimate the accurate fault location due to the cross-term in case the fault location is close to the position where the reference signal is applied to the cable. The proposed method can reduce the cross-term effectively using binarization and morphological image processing, and can estimate the fault location more accurately using the template matching based cross correlation compared to the conventional TFDR. To prove the performance of the proposed method, the actual experiments are carried out in some cases.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.250-260
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• 2015

Purpose: Dual cylindrical microwave chambers equipped with an ohmic heating tube were designed and fabricated to maximize the electric field strength for expeditious heat treatment of particulate foods. Methods: The efficacy of the combination heater was investigated by simulating the electric field distribution by using COMSOL Multiphysics software. Results: All components of the designed microwave heating unit were suitable for transmitting maximal microwave power to the load. The simulated electric field distribution implied that single-mode microwave heating would be sufficient for the steady generation of a highly localized heating zone in the cavity. During impedance matching, the calculated reflection coefficient ($S_{11}$) was small, possibly implying minimal power loss and wave reflection in the designed microwave heating chamber. Conclusions: This study demonstrates the possibility of concentrating the microwave power at the centerline for a single-frequency microwave, for thermal treatment of multiphase foods without attenuating the microwave power.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.671-676
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• 2011

A multilayer square-type piezoelectric transformer with a hole at the center was investigated in this paper. Temperature distribution at the center was improved by using this construction, therefore increasing input voltage and output power. This model was simulated and investigated successfully by applying a finite element method (FEM) in ATILA software. An optimized structure was then fabricated, examined, and compared to the simulation results. Electrical characteristics, including output voltage and output power, were measured at different load resistances. The temperature distribution was also monitored using an infrared camera. The piezoelectric transformer operated at first radial vibration mode and a frequency area of 70 kHz. The 16 W output power was achieved in a three-layer transformer with 96% efficiency and $20^{\circ}C$ temperature rise from room temperature under 115 V driving voltage, 100 ${\Omega}$ matching load, $28{\times}28{\times}1.8mm$ size, and 2 mm hole diameter. With these square-type multilayer piezoelectric transformers, the temperature was concentrated around the hole and lower than in piezoelectric transformers without a hole.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.114-114
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• 2020

Water contamination in a water distribution network (WDN) is harmful since it directly induces the consumer's health problem and suspends water service in a wide area. Actions need to be taken rapidly to countermeasure a contamination event. A contaminant source ident ification (CSI) is an important initial step to mitigate the harmful event. Here, a CSI approach focused on determining the contaminant intrusion possible location and time (PLoT) is introduced. One of the methods to discover the PLoT is an inverse calculation to connect all the paths leading to the report specification of a sensor. A filtering procedure is then applied to narrow down the PLoT using the results from individual sensors. First, we spatially reduce the suspect intrusion points by locating the highly suspicious nodes that have similar intrusion time. Then, we narrow the possible intrusion time by matching the suspicious intrusion time to the reported information. Finally, a likelihood-score is estimated for each suspect. Another important aspect that needs to be considered in CSI is that there are inherent uncertainties, such as the variations in user demand and inaccuracy of sensor data. The uncertainties can lead to overlooking the real intrusion point and time. To reflect the uncertainties in the CSI process, the Monte-Carlo Simulation (MCS) is conducted to explore the ranges of PLoT. By analyzing all the accumulated scores through the random sets, a spread of contaminant intrusion PLoT can then be identified in the network.

• Journal of Distribution Science
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• v.13 no.8
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• pp.97-104
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• 2015

Purpose - This study examines the positive impact of the social distance between producers and users of online content, investigating and analyzing the most popular Web content. In addition, it tries to elicit the matching effect that appears when the individuals'cultural background is consistent with social distance. Research design, data, and methodology - We collected and analyzed actual data about 4,981 videos clips on YouTube, looking at six countries in order to verify the content of this study. Based on the results of the data analysis, the study conducted behavioral measurements on popularity, social distance, culture, and user engagement. The unit of analysis was the content and we collected information about the content producers and the content records. We controlled the views, comments, likes, calendar dates, and ages in the empirical models. The data was collected in 2011, with the records coming from South Korea, Japan, China, U.S., German, and France. A total of 4,980 elements were analyzed in the model. The empirical model estimated is the bivariate negative binomial distribution (NBD) model. Results - It turns out that there is a possibility that the matching effect can be diminished by variables that reflect the psychological involvement of user engagement. This study proposes academic and practical implications based on these research results. This research shows the positive effect of social distance between users and producers on the increased performance of the online content. We find the effect of social distance to be a stronger tendency in collectivism. The collectivists follow their sense of friendship and intimacy in their culture and, the social congruence effect can be found there as well. The effect, however, could erode in a social case where users are motivated by strong intrinsic and psychological factors. In addition, user engagement complicates the process of user decision making regarding the information. Conclusions - This study examines how the differential effects of social distance caused by culture could disappear through user commitment as a complicated user motivation. Some potential implications are as follows. First, a firm in the collectivism culture has to communicate based on the social distance. In fact, most online channels do not have a function that indicates the social distance as measured by favorites or subscribers. This function could help increase the performance of the content in online channels, but this increasing effect can only be found in a collectivist culture. Based on this, the firms have to communicate and announce to users the actual social distance between users and producers. Second, firms should develop a system that discovers the social distance and culture and shows these measures to users and producers, since the congruence effect between social distance and culture is found only for low user engagement. The firms can take the advantage of the congruence effect only for the development of the social distance and culture visualized system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.225-232
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• 2009

In this paper, a new face detection method based on pupil color distribution maps with the frequency under the illumination variance is proposed. Face-like regions are first extracted by applying skin color distribution maps to a color image and then, they are reduced by using the standard deviation of chrominance components. In order to search for eye candidates effectively, the proposed method extracts eye-like regions from face-like regions by using pupil color distribution maps. Furthermore, the proposed method is able to detect eyes very well by segmenting the eye-like regions, based on a lighting compensation technique and a segmentation algorithm even though face regions are changed into dark-tone due to varying illumination conditions. Eye candidates are then detected by means of template matching method. Finally, face regions are detected by using the evaluation values of two eye candidates and a mouth. Experimental results show that the proposed method can achieve a high performance.