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Jonghoon Kim,Hongseok Kim,In-Myoung Kim,Young-Il Kim,Seungyoung Ahn,Jiseong Kim,Joungho Kim 한국전자파학회JEES 2011 Journal of Electromagnetic Engineering and Science Vol.11 No.3
In this paper, we implemented and analyzed a wireless power transfer (WPT) system with a CSPR topology. CSPR refers to constant current source, series resonance circuit topology of a transmitting coil, parallel resonance circuit topology of a receiving coil, and pure resistive loading. The transmitting coil is coupled by a magnetic field to the receiving coil without wire. Although the electromotive force (emf) is small (about 4.5V), the voltage on load resistor is 148V, because a parallel resonance scheme was adopted for the receiving coil. The implemented WPT system is designed to be able to transfer up to 1 ㎾ power and can operate a LED TV. Before the implementation, the EMF reduction mechanism based on the use of ferrite and a metal shield box was confirmed by an EM simulation and we found that the EMF can be suppressed dramatically by using this shield. The operating frequency of the implemented WPT system is 30.7㎑ and the air gap between two coils is 150㎜. The power transferred to the load resistor is 147W and the real power transfer efficiency is 66.4 %.
Coil Design and Shielding Methods for a Magnetic Resonant Wireless Power Transfer System
Jiseong Kim,Jonghoon Kim,Sunkyu Kong,Hongseok Kim,In-Soo Suh,Nam Pyo Suh,Dong-Ho Cho,Joungho Kim,Seungyoung Ahn IEEE 2013 Proceedings of the IEEE Vol.101 No.6
<P>In this paper, we introduce the basic principles of wireless power transfer using magnetic field resonance and describe techniques for the design of a resonant magnetic coil, the formation of a magnetic field distribution, and electromagnetic field (EMF) noise suppression methods. The experimental results of wireless power transfer systems in consumer electronics applications are discussed in terms of issues related to their efficiency and EMF noise. Furthermore, we present a passive shielding method and a magnetic field cancellation method using a reactive resonant current loop and the utilization of these methods in an online electric vehicle (OLEV) system, in which an OLEV green transportation bus system absorbs wireless power from power cables underneath the road surface with only a minimal battery capacity.</P>
Kim, Young-Nam,Kim, Jiseong,Lee, Jeongeun,Kim, Sujung,Lee, Keum-Ah,Kim, Sun-Hyung The Korean Society of Plant Biotechnology 2020 JOURNAL OF PLANT BIOTECHNOLOGY Vol.47 No.4
Reed (Phragmites spp.) is a rhizomatous plant of the Poaceae family and is known as high tolerant plant to heavy metal contaminants. This plant is widely recognized as a Cd root-accumulator, but improved heavy metal tolerance and uptake capacity are still required for phytoremediation efficiency. To enhance capacity of hyperaccumulator plants, ethyl methane sulfonate (EMS) as chemical mutagen has been introduced and applied to remediation approaches. This study aimed to select EMS-mutagenized reeds representing high Cd resistance and large biomass and to investigate their ability of Cd accumulation. After 6 months cultivation of M<sub>2</sub> mutant reeds under Cd stress conditions (up to 1,500 µM), we discovered seven mutant individuals that showed good performances like survivorship, vitality, and high accumulation of Cd, particularly in their roots. Compared to wild type (WT) reeds as control, on average, dry weight of mutant type (MT) reeds was larger by 2 and 1.5 times in roots and shoots, respectively. In addition, these mutant plants accumulated 6 times more Cd, mostly in the roots. In particular, MT8 reeds showed the greatest ability to accumulate Cd. These results suggest that EMS mutagenesis could generate hyperaccumulator plants with enhanced Cd tolerance and biomass, thereby contributing to improvement of phytoremediation efficiency in Cd-contaminated soil or wastewater. Further studies should focus on identifying Cd tolerance mechanisms of such EMS-mutagenized plants, developing techniques for its biomass production, and investigating the practical potential of the EMS mutants for phytoremediation.
Kim, Jonghoon J.,Changhyun Cho,Bumhee Bae,Sukjin Kim,Sunkyu Kong,Heegon Kim,Jung, Daniel H.,Jiseong Kim,Joungho Kim IEEE 2014 IEEE transactions on components, packaging, and ma Vol.4 No.12
<P>A simultaneous switching current (SSC) drawn by an integrated circuit (IC) creates simultaneous switching noise on power nets, which in turn causes jitters in the I/O signals and reduces the maximum clock frequency. For a thorough analysis of high-speed ICs, there is a dire need to measure currents at specific power pins of the ICs. In this paper, a novel magnetically coupled embedded current probing structure is proposed for measuring the SSC on the chip level resulting from the logical activity of the I/O buffers. SSCs are found by capturing the magnetic flux induced by the SSC of interest, with the proposed embedded current probing structure using magnetic coupling, and then reconstructing the original current waveform using the transfer impedance profile. Through a series of measurements with test vehicles fabricated on the chip level, we experimentally verified the proposed probing structures in the time and frequency domains and proved that they can effectively measure the SSC. Finally, future directions for improvements are discussed at the end of this paper.</P>
RISC-V 가상플랫폼 기반 Yolov3-tiny 물체 탐지 딥러닝 모델 구현
김도영 ( Doyoung Kim ),설희관 ( Seol Hui-gwan ),임승호 ( Seung-ho Lim ) 한국정보처리학회 2022 한국정보처리학회 학술대회논문집 Vol.29 No.1
딥러닝 기술의 발전으로 객체 인색, 영상 분석에 관한 성능이 비약적으로 발전하였다. 하지만 고성능 GPU 를 사용하는 컴퓨팅 환경이 아닌 제한적인 엣지 디바이스 환경에서의 영상 처리 및 딥러닝 모델의 적용을 위해서는 엣지 디바이스에서 딥러닝 모델 실행 환경 과 이에 대한 분석이 필요하다. 본 논문에서는 RISC-V ISA 를 구현한 RISC-V 가상 플랫폼에 yolov3-tiny 모델 기반 객체인식 시스템을 소프트웨어 레벨에서 포팅하여 구현하고, 샘플 이미지에 대한 네트워크 딥러닝 연산 및 객체 인식 알고리즘을 적용하여 그 결과를 도출하여 보았다. 본 적용을 바탕으로 RISC-V 기반 임베디드 엣지 디바이스 플랫폼에서 딥러닝 네트워크 연산과 객체 인식 알고리즘의 수행에 대한 분석과 딥러닝 연산 최적화를 위한 알고리즘 연구에 활용할 수 있다.
Sujung Kim,Hualin Nie,Byungki Jun,Jiseong Kim,Jeongeun Lee,Seungill Kim,Ekyune Kim,Sunhyung Kim 한국유전학회 2020 Genes & Genomics Vol.42 No.5
Background Sweet potato is easily propagated by cuttings. But the molecular biological mechanism of adventitious root formation are not yet clear. Objective To understand the molecular mechanisms of adventitious root formation from stem cuttings in sweet potato. Methods RNA-seq analysis was performed using un-rooted stem (0 day) and rooted stem (3 days). Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, comparison with Arabidopsis transcription factors (TFs) of DEGs were conducted to investigate the characteristics of genes and TFs involved in root formation. In addition, qRT-PCR analysis using roots at 0, 3, 6, 9, and 12 days after planting was performed to confirm RNA-seq reliability and related genes expression. Results 42,459 representative transcripts and 2092 DEGs were obtained through the RNA-seq analysis. The DEGs indicated the GO terms related to the single-organism metabolic process and cell periphery, and involved in the biosynthesis of secondary metabolites, and phenylpropanoid biosynthesis in KEGG pathways. The comparison with Arabidopsis thaliana TF database showed that 3 TFs (WRKY, NAC, bHLH) involved in root formation of sweet potato. qRT-PCR analysis, which was conducted to confirm the reliability of RNA-seq analysis, indicated that some metabolisms including oxidative stress and wounding, transport, hormone may be involved in adventitious root formation. Conclusions The detected genes related to secondary metabolism, some hormone (auxin, gibberellin), transports, etc. and 3 TFs (WRKY, NAC, bHLH) may have functions in adventitious roots formation. This results provide valuable resources for future research on the adventitious root formation of sweet potato.
Song, Chiuk,Kim, Hongseok,Jung, Daniel H.,Kim, Jonghoon J.,Kong, Sunkyu,Kim, Jiseong,Ahn, Seungyoung,Kim, Jonghoon,Kim, Joungho [Institute of Electrical and Electronics Engineers 2016 IEEE transactions on electromagnetic compatibility Vol.58 No.4
<P>Wireless power transfer ( WPT) technology is an electrically safe and convenient method of charging batteries. WPT technology allows elimination of exposed contacts, which can cause direct electrocution of human. In spite of the great advantages, the WPT system inevitably generates strong electromagnetic fields ( EMFs), causing interference on the nearby electrical devices as well as harmful influence on human health. Therefore, it is important to satisfy EMF guidelines and reduce leakage magnetic field harmonics in WPT system. For the first time, in this paper, we propose a new tightly coupled handheld resonant magnetic field ( HH-RMF) charger operating at 20 kHz with low EMF and high efficiency. Using a guided magnetic flux in resonance structure, 64.5 mG of EMF is reduced compared to the conventional inductive charger at a distance of 200 mm from edge of the core. In addition to the electromagnetic interference ( EMI) reduction, the isolation inductor scheme is proposed as an EMI reduction method. Through a series of measurements, we experimentally verified that the proposed HH-RMF charger complies with the regulations published by the International Commission on Non-Ionizing Radiation Protection in 1998. The proposed HH-RMF charger with the isolation inductor scheme successfully reduces the third harmonic of the Tx and Rx currents by 23.4 and 11.8 dB mu A, respectively. Furthermore, the third and fifth magnetic field harmonics reduce by 1.38 and 0.67 mG, respectively. The coil-to-coil power transfer efficiency and total system power transfer efficiency of the proposed structure are maintained at over 98% and 84%, respectively.</P>