4-포트 수평/수직 겸용 프로브용 교정키트

김태호(Taeho Kim),김종현(Jonghyeon Kim),김성준(Sungjun Kim),김광호(Kwangho Kim),푸보(Bo Pu),나완수(Wansoo Nah) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.5

본 논문에서는 4-포트 수평/수직 프로브 스테이션을 사용하여 수직 커넥터 핀의 특성 측정 시 사용되는 회로망 분석기의 교정용 키트(calibration kit)를 제안한다. 기존의 수평면에서 사용되는 교정키트를 사용하면, 교정 후 프로브 암의 변경 및 추가적인 장치가 필요하며, 이로 인한 시간 소요뿐 아니라, 주변 상황에 민감한 프로브 팁의 위치 변동에 기인한 정밀도 훼손의 위험이 있다. 본 논문에서는 이를 보완할 수 있는 4-포트 수평/수직 겸용 교정키트를 제시한다. 교정은 SOLT 방법을 이용하였으며, Short, Open, Load는 수평면에서 교정하며, Thru는 프로브의 위치에 따라서 교정기판의 같은 수평면에서 교정하거나 또는 교정기판의 위쪽, 아래쪽을 수직으로 연결하여 사용할 수 있도록 설계/제작하였다. 즉, 기판에 수직한 Thru를 교정할 때에는 교정키트를 수직으로 세워 키트 양면을 사용하여 교정할 수 있는 방법을 제안하였다. 제안한 교정키트에서의 SOLT 회로 반사/전달 특성을 기존 교정키트의 SOLT 회로의 반사/전달 특성과 비교 분석하였으며, 두 교정키트의 전달 특성은 길이 보정 후, 300 kHz부터 8.5 GHz까지 약 ±0.1 dB의 차이가 있음을 확인할 수 있었다. 이와 같이 설계/제작된 4-포트 수평/수직 교정키트의 유용성을 입증하기 위하여 각각 수평 측정의 경우와 수직 측정의 경우의 두 가지 경우 사례 연구를 수행하였으며, 그 결과를 기존의 교정키트를 사용한 후 측정된 결과 데이터와 비교 분석하였다. In this paper, we propose a horizontal/vertical calibration kit for calibrating a vector network analyzer(VNA) to measure the vertical connector pin. If the conventional calibration kit is used, we should change the arm for a probe or need an assistant device and it takes a long time. In addition there is a risk of precision degradation caused by the position change of the probe tip sensitive to the surroundings. We suggest a 4-port vertical calibration kit to make up for the aforementioned shortcomings. The calibration kit was manufactured for the SOLT calibration method. ‘Short’, ‘Open’, and ‘Load’ are available in the horizontal plane, ‘Thru’ is available not only in the horizontal plane on the two planes of a PCB, but in the vertical plane between the two planes according to the positions of the probes. We complemented the conventional calibration kit to make a vertical calibration kit to be used for the vertical measurement method. We compared and analysed their reflection/transfer characteristics of the SOLT calibration standards of the proposed calibration kit and conventional one, we get a ±0.1 dB differences of transfer characteristics in the range from 300 kHz to 8.5 GHz. In order to demonstrate usefulness, and we performed a case study for horizontal and vertical cases, and compared the results of the proposed calibration kit and conventional one.

Transparent and flexible high frequency transmission lines based on composite structure comprising silver nanowires and polyvinyl butyral

Kim, Sang-Woo,Kim, Kwangho,Nah, Wansoo,Lee, Cheul-Ro,Jung, Seung-Boo,Kim, Jong-Woong Elsevier 2018 Composites science and technology Vol.159 No.-

<P><B>Abstract</B></P> <P>Percolated networks of silver nanowires (AgNWs) have attracted intensive attention because of their remarkable mechanical stability, along with their excellent optical and electrical performance for the fabrication of flexible transparent electrodes. Most prior research has mainly focused on fabricating transparent electrodes that can be used in optoelectronic devices such as touch sensors, light emitting diodes, and photovoltaics. However, fabrication of transparent and flexible transmission lines designed to conduct alternating current of high frequency has not been reported so far. Herein, we developed highly transparent, mechanically stable transmission line by employing inverted layer processing (ILP) in order to embed the AgNWs just below the surface of a free-standing transparent polymer. For this, we synthesized polyvinyl butyral (PVB), which can be prepared from polyvinyl alcohol by reaction with butyraldehyde, for AgNW support. AgNWs deposited on a preliminary substrate (glass) were plasmonically sintered to significantly enhance their conductivity, and then transferred to the surface of the cured PVB film by the ILP. Measurements and simulation of specially designed coplanar waveguide circuits comprising AgNWs and PVB revealed that the fabricated electrode can simultaneously provide impressive transmission performance as well as excellent mechanical flexibility and transparency. An interesting finding was that the transmission characteristics and mechanical stability are in a trade-off relationship, which needs to be carefully considered in the design and selection of materials for the flexible transmission lines.</P>

Electrical and mechanical diagnosis of aging 600 V rated STP cables in a nuclear power plant

Kim, Kwangho,Shin, Jaeyoung,Kim, Byung-Sung,Nah, Wansoo,Lim, Chanwoo,Chai, Jangbom Institute of Electrical and Electronic Engineers 2017 IEEE transactions on dielectrics and electrical in Vol.24 No.3

<P>This paper proposes electrical and mechanical diagnostic methods to estimate the aging effects of 14 American wire gage (AWG) 600 V rated shielded twisted pair (STP) cables used in nuclear power plant. The cables were accelerated to be degraded in a dry oven using Arrhenius's equation, and the properties of healthy and degraded cables were estimated electrically and mechanically as well. S-parameters were measured using a vector network analyzer (VNA) and were used to assess the aging effects of the degraded cable. An effective modulus was also used as an aging indicator of the mechanical properties. An indenter was designed and fabricated to measure the effective modulus of aged cables. Both methods' results were compared and found to be effective for diagnosing the deterioration of the aging cables. Therefore, the proposed methods could be very useful for maintaining power cables in nuclear power plants.</P>

Development of bulldozer sensor system for estimating the position of blade cutting edge

Kim, Sang-Ho,Lee, Yong-Seok,Sun, Dong-Ik,Lee, Sang-Keun,Yu, Bo-Hyun,Jang, Sung-Hoon,Kim, Wansoo,Han, Chang-Soo Elsevier 2019 AUTOMATION IN CONSTRUCTION - Vol.106 No.-

<P><B>Abstract</B></P> <P>This paper proposed a bulldozer sensor system for estimating the blade cutting edge position, designed to help bulldozer operators guide the bulldozer blade cutting edge towards a precise position in leveling works. The proposed sensor system consists of two GNSSs, two IMUs, and a position estimation controller. Each sensor and position estimation controller are connected through CAN and RS-232 communications, which facilitate reception of the GNSS's position data and the IMU's angle data as well as the calculation of the bulldozer posture and the blade position. A blade cutting edge position estimation formula is proposed using the frame mapping method reflecting kinematic analysis to calculate the position of the blades. The bulldozer mechanism was modeled, and the effectiveness of the proposed method was verified via simulation to determine accuracy of the estimated positions. The proposed sensor system was then applied to a navigation system to estimate the position of the blade cutting edge after being mounted on an actual bulldozer. The performance of the proposed sensor system was verified by comparing with the positions provided by a commercial GPS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We proposed a sensor system for estimating a bulldozer's blade cutting edge position. </LI> <LI> The sensor system is composed to dual RTK GPS sensor and two motion sensors. </LI> <LI> Kinematic analysis is proposed for estimating a blade's edge position and orientation. </LI> <LI> We performed an experiment to estimate the position of the blade's edge while driving. </LI> <LI> Also, we have verified that its performance has an error within 30 mm. </LI> </UL> </P>

Mechanical Design of the Hanyang Exoskeleton Assistive Robot(HEXAR)

Wansoo Kim,Heedon Lee,Donghwan Kim,Jungsoo Han,Changsoo Han 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10

This study developed a lower extremity exoskeleton system to enhance lower body strength. In this paper, selected the degrees of freedom (DOF) which actuated based on analyzed human motion, and analyzed the human joint function to design the joint modules of the exoskeletal robot. To improve the efficiency of the exoskeleton robot, a mechanical structure was designed on the basis of a semi-anthropomorphic architecture. The Hanyang EXskeleton Assistive Robot (HEXAR) has seven degrees of freedom per leg, two of which are powered by an electrical motor. Appropriately sized motors and gearing are selected, and put through a thorough power analysis. quasi-passive mechanisms were designed with compliance material for supporting the weight of external loads in the stance phase and absorbing/releasing the energy. This paper discusses design criteria considered in mechanical design for HEXAR.

The Role of Planetariums in Astronomy Education

Wansoo Kim,Hyunjin Shim 한국천문학회 2017 天文學會報 Vol.42 No.1

Measurement of Multi-Port S-Parameters using Four-Port Network Analyzer

Kim, Jongmin,Luong, Duc Long,Nah, Wansoo,Kim, SoYoung The Institute of Electronics and Information Engin 2013 Journal of semiconductor technology and science Vol.13 No.6

An efficient measurement methodology is proposed to construct the scattering parameters of a multi-port device using a four-port vector network analyzer (VNA) without the external un-terminated ports. By using the four-port VNA, the reflected waves from the un-terminated ports could be minimized. The proposed method significantly enhances the accuracy of the S-parameters with less number of measurements compared to the results of classical renormalization technique which uses two-port VNA. The proposed method is validated from the measured data with the coupled 8-port micro-strip lines.

Immunity Test for Semiconductor Integrated Circuits Considering Power Transfer Efficiency of the Bulk Current Injection Method

Kim, NaHyun,Nah, Wansoo,Kim, SoYoung The Institute of Electronics and Information Engin 2014 Journal of semiconductor technology and science Vol.14 No.2

The bulk current injection (BCI) and direct power injection (DPI) method have been established as the standards for the electromagnetic susceptibility (EMS) test. Because the BCI test uses a probe to inject magnetically coupled electromagnetic (EM) noise, there is a significant difference between the power supplied by the radio frequency (RF) generator and that transferred to the integrated circuit (IC). Thus, the immunity estimated by the forward power cannot show the susceptibility of the IC itself. This paper derives the real injected power at the failure point of the IC using the power transfer efficiency of the BCI method. We propose and mathematically derive the power transfer efficiency based on equivalent circuit models representing the BCI test setup. The BCI test is performed on I/O buffers with and without decoupling capacitors, and their immunities are evaluated based on the traditional forward power and the real injected power proposed in this work. The real injected power shows the actual noise power level that the IC can tolerate. Using the real injected power as an indicator for the EMS test, we show that the on-chip decoupling capacitor enhances the EM noise immunity.

Isolation and characterization of steroidal saponins from Trigonella foenum -graecum

KIM Chungsook,LEE Eun Ju,KIM Ju Sun,KANG Sam Sik,SON Kun Ho,LEE Je-hyun,CHOI H wansoo,HA Hekyung,LEE Ho Young 大韓藥學會 2006 大韓藥學會 總會 및 學術大會 Vol.2006 No.1

모듈화된 신경망을 사용한 소리 감지 및 위치 추정

김완수(Wansoo Kim),이교구(Kim, Kyogu Lee) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.11

In this paper, we propose and evaluate a novel modular neural network model for sound event localization and detection (SELD). One SELD module extracts arrival time differences and detects sound events from phase and magnitude spectrogram. The assembled neural network model consists of nC2 numbers of SELD modules where n is the number of channels in the microphone array. The modular structure of the proposed model makes the model easier to train using less training data. The structure also makes the model scalable to microphone array shape change.