Reduction of Electromagnetic Field from Wireless Power Transfer Using a Series-Parallel Resonance Circuit Topology

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 %.

A Study on the Red Queen Process and the Evolution of Interfirm Relations

Jonghoon Bae 한국전략경영학회 2010 한국전략경영학회 학술대회발표논문집 Vol.2010 No.4

The Boundaries of Brokerage-Based Knowledge Transfer

Jonghoon Bae(배종훈) 한국인사조직학회 2010 인사조직연구 Vol.18 No.4

본 연구는 Burt(1992)의 구조공백이론에서 주장하고 있는, 중개지위의 지식이전 효과를 참으로 하는 이론적 조건을 분석하고 있다. 이를 위해, 본 연구에서는 중개지위의 지식이전 효과가 전제하고 있는 세 가지 기본 가정을 밝혀내고, 그 개별 가정이 충족되지 않았을 때 중개지위 지식이전 효과가 이론적으로 가능한지 여부를 규명하고 있다. 이를 통해, 어떠한 기본 가정이 Burt(1992)의 구조공백이론의 충분조건인지 살피고 있다. 특히, 본 연구는 정보의 소실에 관한 가정이 중개지위의 지식이전 효과에 충분조건임을 밝히고 있고, 구조공백이론의 효과가 참이 되게 하는 정보 소실의 수준, 즉 허용가능한 정보 소실의 수준에 관한 모형을 제시하고 있다. 또한, 구조공백 이론이 전제하고 있는 세 가지 기본 가정으로부터 두 가지 상이한 중개지위, 즉 대체성 중개지위와 최소차수 중개지위를 연역하고, 정보 소실 수준에 따라 두 가지 중재지위 중 하나가 더 효과적임을 보여주고 있다. 허용가능한 정보 소실 수준을 연결망 형성 비용과 취득 정보의 가치의 비율로 환산할 때, 다음과 같은 결과를 얻었다. 즉, 허용가능한 정보 소실 수준이 높아질수록, 대체성 중개지위가 최소차수 중개지위보다 더 효과적이다. This paper analyzes the theoretical boundaries of brokerage-based knowledge transfer, a model based on Burt’s (1992) structural hole theory. To this end, this paper specifies three theoretical assumptions underlying brokerage-based knowledge transfer and examines whether the violations of those assumptions facilitate or hinder brokerage-based knowledge transfer. In doing so, this paper seeks to identify which assumption is fundamental to brokerage-based knowledge transfer. The following are the three basic assumptions concerning brokerage positions: 1) actors hold knowledge different from one another. 2) the cost of having a tie or forming a relationship is nontrivial. 3) there is no information loss when transferring information from one actor to another. To further examine these assumptions, this paper proposes a model for a tolerable level of information loss that leads to brokerage-based information benefits. In particular, this paper derives two different types of brokerage and shows that brokerage with substitution is preferred to brokerage with minimum direct ties as the ratio of networking cost to information value increases. Moreover, this study shows that the tolerable level of information loss that facilitates brokerage-based knowledge transfer is matched with the cost of having a tie and the ex ante value of knowledge held by partners. In this regard, the working of the third basic assumption is contingent upon that of the first and the second basic assumptions. Finally, it shows that the optimal mix of redundant and non-redundant ties depends again on information loss.

Sliding Mode Observer (SMO) using Aging Compensation based State-of-Charge(SOC) Estimation for Li-Ion Battery Pack

Jonghoon Kim(김종훈),Dmitry Nikitenkov,Valeria Denisova 전력전자학회 2013 전력전자학술대회 논문집 Vol.2013 No.11

Microfluidic Image Cytometry (μFIC) Assessments of Silver Nanoparticle Cytotoxicity

Jonghoon Park,Tae Hyun Yoon 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

Cytotoxicity assessment of silver nanoparticles (AgNPs) was performed using MTT-based microfluidic image cytometry (μFIC). The LC50 value of HeLa cells exposed to AgNPs in the microfluidic device was estimated as 46.7 mg/L, which is similar to that estimated by MTT-based IC for cells cultured in a 96 well plate (49.9 mg/ L). These results confirm that the μFIC approach can produce cytotoxicity data that is reasonably well-matched with that of the conventional 96 well plate system with much higher efficiency. This μFIC method provides many benefits including ease of use and low cost, and is a more rapid in vitro cell based assay for AgNPs. This may aid in speeding up data acquisition in the field of nanosafety and make a significant contribution to the quantitative understanding of nanoproperty- toxicity relationships.

Online State-of-health(SOH) estimation for a LiMn ₂O₄ cell based on fuzzy-logic

Jonghoon Kim,Dmitry Nikitenkov,Jungpil Park 전력전자학회 2013 전력전자학술대회 논문집 Vol.2013 No.7

Discharging/Charging Voltage-Temperature Pattern Recognition for Improved SOC/Capacity Estimation and SOH Prediction at Various Temperatures

Jonghoon Kim,Seongjun Lee,Bohyung Cho 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.1

This study investigates an application of the Hamming network-dual extended Kalman filter (DEKF) based on pattern recognition for high accuracy state-of-charge (SOC)/capacity estimation and state-of-health (SOH) prediction at various temperatures. The averaged nine discharging/charging voltage-temperature (DCVT) patterns for ten fresh Li-Ion cells at experimental temperatures are measured as representative patterns, together with cell model parameters. Through statistical analysis, the Hamming network is applied to identify the representative pattern that matches most closely with the pattern of an arbitrary cell measured at any temperature. Based on temperature-checking process, model parameters for a representative DCVT pattern can then be applied to estimate SOC/capacity and to predict SOH of an arbitrary cell using the DEKF. This avoids the need for repeated parameter measuremet.

The Lasing Characteristics of a Passively Q-Switched Nd:YVO4 Laser Using a Cr:YAG Saturable Absorber

Jonghoon Yi,Jin Hyuk Kwon 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.I

A diode-pumped, passively Q-switched Nd:YVO$_4$ laser was fabricated. A composite crystal, 0.6 \% Nd doped YVO$_4$ crystal block bonded with an undoped YVO$_4$ crystal cap, was used. The end cap reduced thermal lensing as well as thermal stress, when the crystal was end pumped by using a fiber coupled diode laser. Cr:YAG crystals with initial transmission of 80 \% or 90 \% were used as saturable absorbers. For each Cr:YAG crystal, several output couplers with different reflectivity were tested. The variations in the pulsewidth, the pulse repetition rate, and the average output power of the passively Q-switched laser were measured while varying the diode pump power for each value of the output coupler reflectivity and the Cr:YAG initial transmission. The dependences of the lasing characteristics on the output coupler reflectivity and the Cr:YAG initial transmission were explained.

Equivalent Circuit Modeling of PEM Fuel Cell Degradation Combined With a LFRC

Jonghoon Kim,Jaemoon Lee,Cho, B. H. IEEE 2013 IEEE transactions on industrial electronics Vol.60 No.11

<P>This approach investigates with an equivalent circuit modeling a polymer electrolyte membrane (PEM) fuel cell degradation combined with a low-frequency ripple current (LFRC) that may shorten the fuel cell life and worsen the fuel efficiency. Through the immediate measurement of the impedance curves on single cells obtained after cycling for hours and operating in cathode flooding and membrane dehydration modes at variable frequencies, it has been shown that the impedance magnitude of a fuel cell injecting a LFRC increased when compared with that of a high-frequency ripple current. This study develops these investigations one step further by designing equivalent circuit elements like resistance and capacitance by electrochemical impedance spectroscopy. Impedance-based model is able to describe the dynamic behavior of the PEM fuel cell. For validation of the proposed fuel cell model, an experimental study has been carried out for a 1.2-kW Nexa module.</P>

SOC/Capacity Estimation of a Li-Ion Battery based on Pattern Recognition at Different Temperature

Jonghoon Kim,Seongjun Lee,Bohyung Cho 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Differences in electrochemical characteristics among Li-Ion batteries caused by temperature effect result in erroneous state-of-charge (SOC)/capacity estimations when using the existing dual extended Kalman filter (DEKF) algorithm is used. Therefore, this study presents an application of the DEKF based on pattern recognition combined with empirical parameters measurement for high accuracy SOC/capacity estimations at various temperatures. The averaged 9 discharging/charging voltage-temperature (DCVT) patterns for 10 fresh Li-Ion batteries at experimental temperatures are measured as representative patterns, together with battery model parameters such as capacity, open circuit voltage (OCV), and two resistances (Ri, RDiff). Through statistical analysis, the Hamming network is applied for identification of the representative pattern that matches most closely of the pattern of the arbitrary battery to be measured at any temperature. Based on temperature-checking process, model parameters for representative DCVT pattern can be then applied to estimate SOC/capacity of an arbitrary battery using the DEKF. This avoids the need for repeated parameter measurement.