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PV Inverter Operation according to DC Capacitor Aging (직류 커패시터 노후화에 따른 PV 인버터 동작)

  • Yongho Yoon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.2
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    • pp.149-155
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    • 2023
  • Photovoltaic power generation is the most familiar power generation facility among new and renewable energies, and its supply began to expand about 10 years ago, and at this point, interest in solutions and technologies for system maintenance management is increasing. In particular, it is necessary to take measures to maximize the overall efficiency of the solar power generation system, whether or not there is an abnormality in the solar power generation system, and when to replace parts. The PV inverter, one element of the photovoltaic power generation system, is a power conversion system that relies on power switching devices, and DC-Link capacitors are used according to the configuration of DC/DC converters and DC-AC inverters. These DC capacitors also affect system safety (Safety) through renewable energy facilities due to the decrease in power generation of PV inverters, power loss, and increase in harmonics (THD, total distortion of AC output current) due to aging and deterioration due to long-term use. factors can be analyzed. Therefore, in this paper, the PV inverter operating characteristics according to the DC capacitor capacity state currently operating in the photovoltaic power generation system were considered, and research contents were proposed to secure the safety and reliability of renewable energy facilities.

Field Phenotyping of Plant Height in Kenaf (Hibiscus cannabinus L.) using UAV Imagery (드론 영상을 이용한 케나프(Hibiscus cannabinus L.) 작물 높이의 노지 표현형 분석)

  • Gyujin Jang;Jaeyoung Kim;Dongwook Kim;Yong Suk Chung;Hak-Jin Kim
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.67 no.4
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    • pp.274-284
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    • 2022
  • To use kenaf (Hibiscus cannabinus L.) as a fiber and livestock feed, a high-yielding variety needs to be identified. For this, accurate phenotyping of plant height is required for this breeding purpose due to the strong relationship between plant height and yield. Plant height can be estimated using RGB images from unmanned aerial vehicles (UAV-RGB) and photogrammetry based on Structure from Motion (SfM) algorithms. In kenaf, accurate measurement of height is limited because kenaf stems have high flexibility and its height is easily affected by wind, growing up to 3 ~ 4 m. Therefore, we aimed to identify a method suitable for the accurate estimation of plant height of kenaf and investigate the feasibility of using the UAV-RGB-derived plant height map. Height estimation derived from UAV-RGB was improved using multi-point calibration against the five different wooden structures with known heights (30, 60, 90, 120, and 150 cm). Using the proposed method, we analyzed the variation in temporal height of 23 kenaf cultivars. Our results demontrated that the actual and estimated heights were reliably comparable with the coefficient of determination (R2) of 0.80 and a slope of 0.94. This method enabled the effective identification of cultivars with significantly different heights at each growth stages.

A Study on the Methods to Improve High-Wave Reproducibility during Typhoon (태풍 내습 시의 고파 재현성 개선방안 연구)

  • Jong-Dai, Back;Kyong-Ho, Ryu;Jong-In, Lee;Weon-Mu, Jeong;Yeon-S., Chang
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.34 no.6
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    • pp.177-187
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    • 2022
  • This study estimates the design wave in the event of a typhoon attack at Busan new port using the wind field, the revised shallow water design wave estimation method proposed by the Ministry of Oceans and Fisheries in 2020, and proposed a reliable method of calculating the shallow water design through verification with the wave observation data. As a result of estimating typhoon wave using the wind field and SWAN numerical model, which are commonly used in the field work, for typhoon that affected Busan new port, it was found that reproducibility was not good except typhoons KONG-REY(1825) and MAYSAK(2009). In particular, in the case of typhoon MAEMI(0314), which had the greatest impact on Busan new port, the maximum significant wave height was estimated to be about 35.0% smaller than that of the observed wave data. Therefore, a plan to improve the reproducibility of typhoon wave was reviewed by applying the method of correcting the wind field and the method of using the Boussinesq equation numerical model, respectively. As a result of the review, it was found that the reproducibility of the wind field was not good as before when the wind field correction. However as a method of linking wind field data, SWAN model results, and Boussinesq numerical model, typhoon wave was estimated during typhoon MAEMI(0314), and the maximum significant wave was similar to the wave observations, so it was reviewed to have good reproducibility.

Analysis of the Distribution and Diversity of the Microbial Community in Kimchi Samples from Central and Southern Regions in Korea Using Next-generation Sequencing (차세대 염기서열 분석법을 이용한 우리나라 중부지방과 남부지방의 김치 미생물 군집의 분포 및 다양성 분석)

  • Yunjeong Noh;Gwangsu Ha;Jinwon Kim;Soo-Young Lee;Do-Youn Jeong;Hee-Jong Yang
    • Journal of Life Science
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    • v.33 no.1
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    • pp.25-33
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    • 2023
  • The fermentation process of kimchi, which is a traditional Korean food, influences the resulting compo- sition of microorganisms, such as the genera Leuconostoc, Weissella, and Lactobacillus. In addition, several factors, including the type of kimchi, fermentation conditions, materials, and ingredients, can influence the distribution of the kimchi microbial community. In this study, next-generation sequencing (NGS) of kimchi samples obtained from central (Gangwon-do and Gyeonggi-do) and southern (Jeolla-do and Gyeongsang-do) regions in Korea was performed, and the microbial communities in samples from the two regions were compared. Good's coverage prediction for all samples was higher than 99%, indicating that there was sufficient reliability for comparative analysis. However, in a α -diversity analysis, there was no significant difference in species richness and diversity between samples. The Firmicutes phylum was common in both regions. At the species level, Weissella kandleri dominated in central (46.5%) and southern (30.8%) regions. Linear discriminant analysis effect size (LEfSe) analysis was performed to identify biomarkers representing the microbial community in each region. The LEfSe results pointed to statistically significant differences between the two regions in community composition, with Leuconostocaceae (71.4%) dominating in the central region and Lactobacillaceae (61.0%) dominating in the southern region. Based on these results, it can be concluded that the microbial communities of kimchi are significantly influenced by regional properties and that it can provide more useful scientific data to study the relationship between regional characteristics of kimchi and their microbial distribution.

Private Blockchain and Biometric Authentication-based Chronic Disease Management Telemedicine System for Smart Healthcare (스마트 헬스케어를 위한 프라이빗 블록체인과 생체인증기반의 만성질환관리 원격의료시스템)

  • Young-Ae Han;Hyeok Kang;Keun-Ho Lee
    • Journal of Internet of Things and Convergence
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    • v.9 no.1
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    • pp.33-39
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    • 2023
  • As the number of people with chronic diseases increases due to an aging society, it is urgent to prevent and manage their diseases. Although biometric authentication methods and Telemedicine Systems have been introduced to solve these problems, it is difficult to solve the security problem of medical information and personal authentication. Since smart healthcare includes personal medical information of subjects, the security of personal information is the most important field. Therefore, in this paper, we tried to propose a Telemedicine System using a smart wearable device ECG in the form of a wristband and face personal authentication in a private blockchain environment. This system targets various medical personnel and patients with chronic diseases in all regions, and uses a private blockchain that can increase data integrity and transparency, ECG and face authentication that are difficult to forge and alter and have high personal identification to provide a system with high security and reliability. composed. Through this, it is intended to contribute to increasing the efficiency of chronic disease management by focusing on disease prevention and health management for patients with chronic diseases at home.

Principle and Application of 'Image-mapping' in-situ U-Pb Carbonate Age-dating ('Image-mapping' in-situ U-Pb 탄산염광물 연대측정법의 원리 및 적용)

  • Ha Kim;Seongsik Hong;Chaewon Park;Jihye Oh;Jonguk Kim;Yungoo Song
    • Economic and Environmental Geology
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    • v.56 no.2
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    • pp.115-123
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    • 2023
  • We introduce a new 'image-mapping' in-situ U-Pb dating method using LA-ICP-MS, proposed by Drost et al. (2018), and show the characteristics and usability of this method through several examples of absolute age results determined by first applying it to samples from the Joseon Supergroup of the Early Paleozoic Era in Korea. Unlike the previous in-situ spot analysis, this in-situ U-Pb dating method for carbonate minerals can determine the absolute age with high reliability by applying the 'image-mapping' method of micro-sized domains based on micro-textural observation, as well as determine the absolute age of multiple geological 'events' that occurred after deposition. This was confirmed in the case of determining the syn-depositional age and the multiple post-depositional ages from carbonate minerals of the Makgol and the Daegi Formations. Therefore, if the 'image-mapping' in-situ U-Pb dating method is applied to determine the absolute age of various types of carbonate minerals that exist in various geological environments throughout the geologic era, it will be possible to secure new geological age information.

Fake News Detection on YouTube Using Related Video Information (관련 동영상 정보를 활용한 YouTube 가짜뉴스 탐지 기법)

  • Junho Kim;Yongjun Shin;Hyunchul Ahn
    • Journal of Intelligence and Information Systems
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    • v.29 no.3
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    • pp.19-36
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    • 2023
  • As advances in information and communication technology have made it easier for anyone to produce and disseminate information, a new problem has emerged: fake news, which is false information intentionally shared to mislead people. Initially spread mainly through text, fake news has gradually evolved and is now distributed in multimedia formats. Since its founding in 2005, YouTube has become the world's leading video platform and is used by most people worldwide. However, it has also become a primary source of fake news, causing social problems. Various researchers have been working on detecting fake news on YouTube. There are content-based and background information-based approaches to fake news detection. Still, content-based approaches are dominant when looking at conventional fake news research and YouTube fake news detection research. This study proposes a fake news detection method based on background information rather than content-based fake news detection. In detail, we suggest detecting fake news by utilizing related video information from YouTube. Specifically, the method detects fake news through CNN, a deep learning network, from the vectorized information obtained from related videos and the original video using Doc2vec, an embedding technique. The empirical analysis shows that the proposed method has better prediction performance than the existing content-based approach to detecting fake news on YouTube. The proposed method in this study contributes to making our society safer and more reliable by preventing the spread of fake news on YouTube, which is highly contagious.

Reliability Analysis of Finger Joint Range of Motion Measurements in Wearable Soft Sensor Gloves (웨어러블 소프트 센서 장갑의 손가락 관절 관절가동범위 측정에 대한 신뢰도 분석)

  • Eun-Kyung Kim;Jin-Hong Kim;Yu-Ri Kim;Ye-Ji Hong;Gang-Pyo Lee;Eun-Hye Jeon;Joon-bum Bae;Su-in Kim;Sang-Yi Lee
    • PNF and Movement
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    • v.21 no.2
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    • pp.171-183
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    • 2023
  • Purpose: The purpose of this study was to compare universal goniometry (UG), which is commonly used in clinical practice to measure the range of motion (ROM) of finger joints with a wearable soft sensor glove, and to analyze the reliability to determine its usefulness. Methods: Ten healthy adults (6 males, 4 females) participated in this study. The metacarpophalangeal joint (MCP), interphalangeal joint (IP), and proximal interphalangeal joint (PIP) of both hands were measured using UG and Mollisen HAND soft sensor gloves during active flexion, according to the American Society for Hand Therapists' measurement criteria. Measurements were taken in triplicate and averaged. The mean and standard deviation of the two methods were calculated, and the 95% limits of agreement (LOA) of the measurements were calculated using the intraclass correlation coefficient (ICC) and Bland-Altman plot to examine the reliability and discrepancies between the measurements. Results: The results of the mean values of the flexion angles for the active range of motion (AROM) of the finger joints showed large angular differences in the finger joints, except for the MCP of the thumb. In the inter-rater reliability analysis according to the measurement method, the ICC (2, 1) value showed a low level close to 0, and the mean difference by the Bland-Altman plot showed a value greater than 0, showing a pattern of discrepancy. The 95% LOA had a wide range of differences. Conclusion: This study is a preliminary study investigating the usefulness of the soft sensor glove, and the reliability analysis showed a low level of reliability and inconsistency. However, if future studies can overcome the limitations of this study and the technical problems of the soft sensor glove in the development stage, it is suggested that the measurement instrument can show more accurate measurement and higher reliability when measuring ROM with UG.

A Study on Derivation of Public Conflict Management Countermeasure in the Port Sector (항만분야 공공갈등 관리방안 도출에 관한 연구)

  • Ga-Hyun Kim;Se-Won Kim;Hye-Ryeong Lee
    • Journal of Navigation and Port Research
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    • v.47 no.4
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    • pp.246-255
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    • 2023
  • Public conflicts in the port sector can cause additional social costs and delay the supply of port infrastructure, which can negatively affect local industries and national competitiveness. Although the importance of conflict management in the port sector is gradually increasing, there is still no systematic conflict management countermeasure. Therefore, in this study, the limitations of the current conflict management system in the port sector were considered, and a Delphi survey was conducted targeting experts and stakeholders in the port sector and conflict management. In addition, criteria for diagnosing conflicts in the port sector, causes of conflicts, proactive management measures, and ex post solutions were derived. The results of the Delphi survey analysis showed that the biggest causes of conflict were the absence of stakeholder opinion collection, consultation, and communication tools. Preliminary conflict management measures including a public deliberation process to collect local opinions and discuss development directions before deciding on specific issues, and ex post conflict resolution measures including investigation of causes of conflicts and objective personnel management in the process of preparing alternatives (e.g., securing reliability) were determined as the most important factors. In addition, based on the results obtained in this study, conflict management techniques for each phase of the port development project were presented. These findings are expected to be used as a useful reference material to reflect the port sector, which has not been included in the "Public Institution Conflict Management Manual (2016)" of the Office for Government Policy Coordination.

National Awareness of the 2019 World Swimming Championships using Big Data from Social Network Analysis (소셜네트워크 분석의 빅데이터를 활용한 2019세계수영선수권 대회의 국내 인식조사)

  • Kim, Gi-Tak
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.4
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    • pp.173-184
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    • 2019
  • The data processing of this study is based on the word data search in social media through textom and the big data analysis is carried out and three areas (2019 Gwangju World Swimming Championships, 2019 Gwangju World Swimming Masters Competition, 2019 World Swimming Championships Problem) was consistently handled through data collection and refinement in the web environment. We applied the collected words to the program of Ucinet6, visualized them, and conducted a CONCOR analysis to grasp the similar relationship of words and to identify the cluster of common factors. As a result of the analysis, the clusters related to the 2019 Gwangju World Swimming Championships mainly consisted of four major areas of recognition and perception, mainly searching for operational aspects related to the swimming championship, and the community related to the 2019 Gwangju World Swimming Masters Competition Is mainly searched for the promotion of the Masters Competition and the aspect of the competition divided into two areas of major recognition and peripheral recognition. The cluster related to the problems of the 2019 Gwangju World Swimming Championships is divided into five areas, And they are mainly searching for the place, operation, institution, event, etc. of the problem of the swimming championship.