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Journal of Modern Power Systems and Clean Energy 2018年第3期6卷 509-520页

作者： chul-Ho NOH chul-hwan kim Gi-Hyeon GWON Yun-Sik OH College of Information and Communication Engineering Sungkyunkwan University

The increasing importance of energy efficiency has led to several studies related to the construction of a reliable low voltage DC(LVDC) distribution ***, studies on a protection scheme that considers the fault characteristics of an LVDC distribution system are essential to improve system reliability. When compared to a conventional distribution system, the most distinct feature of an LVDC distribution system is the existence of a capacitive discharge current from converters under a fault condition that results in the prompt operation of protection devices. Therefore, this study involves proposing a precise and rapid technique to identify the fault section in an LVDC distribution system. The technique involves two stages, namely: an analysis stage to analyze the capacitive discharge current and a decision stage to identify the fault section based on the fault type. A detailed discussion of each step is presented and its feasibility is verified based on the results of simulations with an ElectroMagnetic Transients Program and MATLAB~?.

关键词： Capacitive discharge current Fault section identification Fault type identification Low voltage DC distribution system

Intelligent Islanding Detection of Multi-distributed Generation Using Artificial Neural Network Based on Intrinsic Mode Function Feature

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 511-520页

作者： Samuel Admasie Syed Basit Ali Bukhari Teke Gush Raza Haider chul hwan kim Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwonSouth Korea U.S.-Pakistan Center for Advanced Studies in Energy(USPCAS-E) National University of Sciences and Technology(NUST)H-12 IslamabadPakistan Department of Electrical Engineering Balochistan University of Engineering and TechnologyKhuzdar 89100Pakistan

The integration of distributed energy resources(DERs) into distribution networks is becoming increasingly important, as it supports the continued adoption of renewable power generation, combined heat and power plants, and storage systems. Nevertheless, inadvertent islanding operation is one of the major protection issues in distribution networks connected to DERs. This study proposes an intelligent islanding detection method(IIDM) using an intrinsic mode function(IMF)feature-based grey wolf optimized artificial neural network(GWO-ANN). In the proposed IIDM, the modal voltage signal is pre-processed by variational mode decomposition followed by Hilbert transform on each IMF to derive highly involved features. Then, the energy and standard deviation of IMFs are employed to train/test the GWO-ANN model for identifying the islanding operations from other non-islanding events. To evaluate the performance of the proposed IIDM, various islanding and non-islanding conditions such as faults, voltage sag, linear and nonlinear load and switching, are considered as the training and testing datasets. Moreover, the proposed IIDM is evaluated under noise conditions for the measured voltage signal. The simulation results demonstrate that the proposed IIDM is capable of differentiating between islanding and non-islanding events without any sensitivity under noise conditions in the test signal.

关键词： Distributed energy resource(DER) intrinsic mode function(IMF) grey wolf optimized artificial neural network(GWO-ANN) intelligent islanding detection method(IIDM) microgrid

Fault area estimation using traveling wave for wide area protection

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Journal of Modern Power Systems and Clean Energy 2016年第3期4卷 478-486页

作者： Jae-Won LEE Won-Ki kim Joon HAN Won-Hyeok JANG chul-hwan kim Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Daewoo Shipbuilding&Marine Engineering Co. Ltd.GeojeRepublic of Korea Electrical and Computer Engineering Department University of Illinois at Urbana-ChampaignChampaignILUSA

As the increasing number of Phasor Measurement Units(PMUs) are deployed, wide area protection in power systems has been gaining interest. In particular, fault detection, fault classification and fault area estimation are essential to reduce the damage of faults, and even prevent catastrophic cascades of failures. In this paper, we present a scheme for fault area estimation using PMUs and traveling wave theory. The purpose of this paper is to formulate a scheme for fault area estimation by calculating the approximate fault location based on traveling wave *** research has targeted at reliable operation of wide transmission system through the estimation of fault *** verify the suggested scheme, the various simulations are performed in practical Korean power transmission *** simulation results show that the proposed scheme has a good performance with high accuracy for estimating fault area.

关键词： Fault area estimation Phasor measurement unit(PMU) Transmission line system Traveling wave Wide area protection

Water-filling algorithm based approach for management of responsive residential loads

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Journal of Modern Power Systems and Clean Energy 2018年第1期6卷 118-131页

作者： Zunaib Maqsood HAIDER Khawaja Khalid MEHMOOD Muhammad Kashif RAFIQUE Saad Ullah KHAN Soon-Jeong LEE chul-hwan kim College of Information and Communication Engineering Sungkyunkwan University

Integration of large number of electric vehicles(EVs)with distribution networks is devastating for conventional power system devices such as transformers and power lines *** paper proposes a methodology for management of responsive household appliances management and EVs with water-filling *** the proposed scheme,the load profile of a transformer is retained below its rated capacity while minimally affecting the associated *** the instantaneous demand at transformer increases beyond its capacity,the proposed methodology dynamically allocates demand curtailment limit(DCL)to each home served by *** DCL allocation takes convenience factors,load profile and information of flexible appliances into account to assure the comfort of all the *** proposed scheme is verified by modeling and simulating five houses and a distribution *** smart appliances such as an HVAC,a water heater,a cloth dryer and an EV are also modeled for the *** show that the proposed scheme performs to reduce overloading effects of the transformer efficiently and assures comfort of the consumers at the same time.

关键词： Water-filling(WF) algorithm Responsive household appliances management(RHAM) Electric vehicle(EV) Demand curtailment limit(DCL) Convenience factor Load profile

Very Short-Term Generating Power Forecasting for Wind Power Generators Based on Time Series Analysis

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Smart Grid and Renewable Energy 2013年第2期4卷 181-186页

作者： Atsushi Yona Tomonobu Senjyu Funabashi Toshihisa chul-hwan kim Meidensha Corporation Tokyo Japan Sungkyunkwan University Suwon City South Korea. University of the Ryukyus Okinawa Japan

In recent years, there has been introduction of alternative energy sources such as wind energy. However, wind speed is not constant and wind power output is proportional to the cube of the wind speed. In order to control the power output for wind power generators as accurately as possible, a method of wind speed estimation is required. In this paper, a technique considers that wind speed in the order of 1 - 30 seconds is investigated in confirming the validity of the Auto Regressive model (AR), Kalman Filter (KF) and Neural Network (NN) to forecast wind speed. This paper compares the simulation results of the forecast wind speed for the power output forecast of wind power generator by using AR, KF and NN.

关键词： Very Short-Term Ahead Forecasting Wind Power Generation Wind Speed Forecasting Time Series Analysis

Electrochemical biosensors for point-of-care testing

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Bio-Design and Manufacturing 2024年第4期7卷 548-565页

作者： Jinsol kim Juho Jeong Seung hwan Ko Department of Mechanical Engineering Seoul National UniversitySeoul 08826Republic of Korea Institute of Advanced Machinery and Design(SNU-IAMD) Seoul National UniversitySeoul 08826Republic of Korea

Point-of-care testing(POCT)is the practice of diagnosing and monitoring diseases where the patient is located,as opposed to traditional treatment conducted solely in a medical laboratory or other clinical *** has been less common in the recent past due to a lack of portable medical devices capable of facilitating effective medical ***,recent growth has occurred in this field due to advances in diagnostic technologies,device miniaturization,and progress in wearable *** these developments,electrochemical sensors have attracted interest in the POCT field due to their high sensitivity,compact size,and *** are used in various applications,from disease diagnosis to health status *** this paper we explore recent advancements in electrochemical sensors,the methods of fabricating them,and the various types of sensing mechanisms that can be ***,we delve into methods for immobilizing specific biorecognition elements,including enzymes,antibodies,and aptamers,onto electrode surfaces and how these sensors are used in real-world POCT settings.

关键词： Point-of-care testing(POCT) Electrochemical sensor Enzyme Antibody Health care

Programmable directional color dynamics using plasmonics

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Microsystems & Nanoengineering 2024年第1期10卷 325-334页

作者： Gyurin kim Doeun kim Soeun Ko Jang-hwan Han Juhwan kim Joo hwan Ko Young Min Song Hyeon-Ho Jeong School of Electrical Engineering and Computer Science Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Department of Semiconductor Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Artificial Intelligence(AI)Graduate School Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual ***,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural ***,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer *** nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission ***,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible ***,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

关键词： directional prevailing exceptional

Myostatin gene role in regulating traits of poultry species for potential industrial applications

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Journal of Animal Science and Biotechnology 2024年第5期15卷 1793-1801页

作者： Joonbum Lee Dong‑hwan kim Kichoon Lee Department of Animal Sciences The Ohio State UniversityColumbusOH 43210USA

The myostatin(MSTN)gene is considered a potential genetic marker to improve economically important traits in live-stock,since the discovery of its function using the MSTN knockout *** anti-myogenic function of the MSTN gene was further demonstrated in farm animal species with natural or induced *** poultry species,myo-genesis in cell culture was regulated by modulation of the MSTN ***,different expression levels of the MSTN gene in poultry models with different muscle mass have been reported,indicating the conserved myogenic function of the MSTN gene between mammalian and avian *** advances of CRISPR/Cas9-mediated genome edit-ing techniques have led to development of genome-edited poultry species targeting the MSTN gene to clearly dem-onstrate its anti-myogenic function and further investigate other potential functions in poultry *** review summarizes research conducted to understand the function of the MSTN gene in various poultry models from cells to whole ***,the genome-edited poultry models targeting the MSTN gene are reviewed to inte-grate diverse effects of the MSTN gene on different traits of poultry species.

关键词： Chicken Economic traits Myostatin Quail

Decision Technique of Solar Radiation Prediction Applying Recurrent Neural Network for Short-Term Ahead Power Output of Photovoltaic System

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Smart Grid and Renewable Energy 2013年第6期4卷 32-38页

作者： Atsushi Yona Tomonobu Senjyu Toshihisa Funabashi Paras Mandal chul-hwan kim Meidensha Corporation Tokyo Japan Sungkyunkwan University Suwon City South Korea University of Texas at El Paso El Paso USA University of the Ryukyus Okinawa Japan 2Meidensha Corporation Tokyo Japan

In recent years, introduction of a renewable energy source such as solar energy is expected. However, solar radiation is not constant and power output of photovoltaic (PV) system is influenced by weather conditions. It is difficult for getting to know accurate power output of PV system. In order to forecast the power output of PV system as accurate as possible, this paper proposes a decision technique of forecasting model for short-term-ahead power output of PV system based on solar radiation prediction. Application of Recurrent Neural Network (RNN) is shown for solar radiation prediction in this paper. The proposed method in this paper does not require complicated calculation, but mathematical model with only useful weather data. The validity of the proposed RNN is confirmed by comparing simulation results of solar radiation forecasting with that obtained from other

关键词： Neural Network Short-Term-Ahead Forecasting Power Output for PV System Solar Radiation Forecasting

Nanocrystalline low-silica X zeolite as an efficient ion-exchanger enabling fast radioactive strontium capture

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 15-23页

作者： Hyungmin Jeon Susung Lee Jeong-chul kim Minkee Choi Department of Chemical and Biomolecular Engineering(BK21 Four) Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea Center for Nanomaterials and Chemical Reactions Institute for Basic Science(IBS)Daejeon 34141Republic of Korea

NaA zeolite(Si/Al=1.00)has been commercially applied for capturing radioactive 90Sr^(2+)because of its high surface charge density,effectively stabilizing the multivalent ***,owing to its narrow micropore opening(4.0Å),large micron-sized crystallites,and bulkiness of hydrated Sr^(2+),the Sr^(2+)exchange over NaA has been limited by very slow *** this study,we synthesized nanocrystalline low-silica X by minimizing a water content in a synthesis gel and utilizing a methyl cellulose hydrogel as a crystal growth *** resulting zeolite exhibited high crystallinity and Al-rich framework(Si/Al of approximately 1.00)with the sole presence of tetrahedral Al sites,which are capable of high Sr^(2+)uptake and ion ***,the zeolite with a FAU topology has a much larger micropore opening size(7.4Å)and a much smaller crystallite size(~340 nm)than NaA,which enable significantly enhanced ion-exchange *** to conventional NaA,the nanocrystalline low-silica X exhibited remarkably increased Sr^(2+)-exchange kinetics(>18-fold larger rate constant)in batch *** both the nanocrystalline low-silica X and NaA exhibited comparable Sr^(2+)capacities under equilibrated conditions,the former demonstrated a 5.5-fold larger breakthrough volume than NaA under dynamic conditions,attributed to its significantly faster Sr^(2+)-exchange kinetics.

关键词： Sr^(2+)removal low-silica X zeolite nanocrystal hydrogel methyl cellulose