• Title/Summary/Keyword: 마이크로 크기

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A Study on the Speed Sensorless Vector Control for Induction Motor Adaptive Control Method using a High Frequency Boost Chopper of Hybrid Type Piezoelectric Transformer (하이브리드형 압전 변압기의 고주파 승압 초퍼를 이용한 적응제어기법 유도전동기 속도 센서리스 벡터제어에 관한 연구)

  • Hwang, Lark-Hoon;Na, Seung-Kwon;Kim, Yeong-Wook;Choi, Song-Shik
    • Journal of Advanced Navigation Technology
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    • v.17 no.3
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    • pp.332-345
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    • 2013
  • In this paper, recently, it is described to the piezoelectric transformer technology develops, because it was have to favorable characteristics such as electromagnetic-noise free, compact size, higher efficiency, and superior power density, flux linkage, noiseless, etc. its resonance frequency was used to output waveform of a sine wave. A rotor speed identification method of induction motor based on the theory of flux model reference adaptive system(FMRAS). The estimator execute the rotor speed identification so that the vector control of the induction motor may be achieved. The improved auxiliary variable of the model are introduced to perform accurate rotor speed estimation. The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM techniuqe and DC-DC converter. High speed calculation and processing for vector control is carried out by digital signal one chip microprocessor. Validity of the proposed control method is verified through simulation and experimental results.

Design of a Binary Adder Structure Suitable for High-Security Public Key Cryptography Processor (고비도 공개키 암호화 프로세서에 적합한 이진 덧셈기의 구조 연구)

  • Moon, Sang-Gook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.11
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    • pp.1976-1979
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    • 2008
  • Studies on binary adder have been variously developed. According to those studies of critical worst delay and mean delay time of asynchronous binary adders, carry select adders (CSA) based on hybrid structure showed 17% better performance than ripple carry adders (RCA) in 32 bit asynchronous processors, and 23% better than in 64 bit microprocessor implemented. In the complicated signal processing systems such as RSA, it is essential to optimize the performance of binary adders which play fundamental roles. The researches which have been studied so far were subject mostly to addition algorithms or adder structures. In this study, we analyzed and designed adders in an asp;ect of synthesis method. We divided the ways of implementing adders into groups, each of which was synthesized with different synthesis options. Also, we analyzed the variously implemented adders to evaluate the performance and area so that we can propose a different approach of designing optimal binary adders.

Estimation of Cloud Liquid Watetr used by GMS-5 Observations (GMS-5 자료를 이용한 구름 수액량 추정 연구)

  • 차주완;윤홍주
    • Korean Journal of Remote Sensing
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    • v.15 no.1
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    • pp.21-30
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    • 1999
  • The CLW (Cloud Liquid Water) is a parameter of vital interest in both modeling and forecasting weather. In mesoscale models, the magnitude of latent heat effects corresponds to the amount of CLW, which is important in the development of a certain weather system. The goal of this study is the estimation of CLW by GMS-5 data which is compared with that of SSM/I data and GMR(Grounded Microwave Radiometer)data. First of all, we found out the relationship of cloud albedo to cloud thickness, and caculated the CLW using the result of the relationship. The CLW amount of SSM/I or GMR and that of GMS-5 were compared, respectively. The correlation coefficient was about 0.86 and RMSE was 9.23 mg/$cm^2$ between GMS-5 data and GMR data. And also the correlation coefficient was 0.84 and RMSE was 14.02 mg/$cm^2$ between GMS-5 data and SSM/I data.

Synthesis of size-controlled ZnO tetrapods sizes using atmospheric microwave plasma system and evaluation of its photocatalytic property (대기압 마이크로웨이브 플라즈마를 이용한 다양한 크기의 ZnO tetrapod 합성 및 광촉매 특성 평가)

  • Heo, Sung-Gyu;Jeong, Goo-Hwan
    • Journal of the Korean institute of surface engineering
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    • v.54 no.6
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    • pp.340-347
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    • 2021
  • Among various metal oxide semiconductors, ZnO has an excellent electrical, optical properties with a wide bandgap of 3.3 eV. It can be applied as a photocatalytic material due to its high absorption rate along with physical and chemical stability to UV light. In addition, it is important to control the morphology of ZnO because the size and shape of the ZnO make difference in physical properties. In this paper, we demonstrate synthesis of size-controlled ZnO tetrapods using an atmospheric pressure plasma system. A micro-sized Zn spherical powder was continuously introduced in the plume of the atmospheric plasma jet ignited with mixture of oxygen and nitrogen. The effect of plasma power and collection sites on ZnO nanostructure was investigated. After the plasma discharge for 10 min, the produced materials deposited inside the 60-cm-long quartz tube were obtained with respect to the distance from the plume. According to the SEM analysis, all the synthesized nanoparticles were found to be ZnO tetrapods ranging from 100 to 600-nm-diameter depending on both applied power and collection site. The photocatalytic efficiency was evaluated by color change of methylene blue solution using UV-Vis spectroscopy. The photocatalytic activity increased with the increase of (101) and (100) plane in ZnO tetrapods, which is caused by enhanced chemical effects of plasma process.

Design and Manufacture of Triple-Band Antennas with Two Branch Line and a Vertical Line for WLAN/WiMAX system applications (2개 분기선로와 수직 선로를 갖는 WLAN/WiMAX 시스템에 적용 가능한 삼중대역 안테나 설계 및 제작)

  • Choi, Tae-Il;Yoon, Joong-Han
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.6
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    • pp.740-747
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    • 2019
  • In this paper, an antenna applicable to WLAN and WiMAX frequency bands is designed, fabricated, and measured. The proposed antenna is designed to have two branch strip line in the patch plane and a rectangular slit in the ground plane based on microstrip feeding for triple band characteristics and added a vertical strip in the ground plane to enhance impedance bandwidth characteristics. The proposed antenna is designed on a substrate with a relative permittivity of 4.4, a thickness of 1.0 mm, and has a size of $18.0mm(W1){\times}37.3mm$ (L4+L5+L7). From the fabricated and measured results, impedance bandwidths of 480 MHz (2.32 to 2.80 GHz) for 2.4/2.5 GHz band, 810 MHz (3.22 to 4.03 GHz) for 3.5 GHz band, and 1,820 MHz (5.05 to 6.87 GHz) for 5.0 GHz band were obtained based on the impedance bandwidth. Measured 3D pattern and gains are displayed.

Design of an Inexpensive Heater using Chip Resistors for a Portable Real-time Microchip PCR System (저항소자를 이용한 휴대형 Real-time PCR 기기용 히터 제작)

  • Choi, Hyoung-jun;Kim, Jeong-tae;Koo, Chi-wan
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.295-301
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    • 2019
  • A heater in a portable real-time polymerase chain reaction(PCR) system is one of the important factors for controlling the PCR thermocycle precisely. Since heaters are integrated on a small-sized PCR chip for rapid heating and fabricated by semiconductor processes, the cost of producing PCR chips is high. Here, we propose to use chip resistors as an inexpensive and accurate temperature control method. The temperature distribution was simulated using one or two chip resistors on a real-time PCR chip and the PCR chip with uniform temperature distribution was fabricated. The temperature rise and fall rates were $18^{\circ}C/s$ and $3^{\circ}C/s$, respectively.

Design of transistor oscillator for X-band application using a pair of L-shaped monopole slot resonator (한 쌍의 L-형 모노폴 슬롯 공진기를 이용한 X-밴드 트랜지스터 발진기 설계)

  • Lee, Yeong-min;Lee, Young-soon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.21 no.1
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    • pp.107-114
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    • 2021
  • In this paper, a planar transistor oscillator for X-band using a newly proposed L-shaped monopole slot resonator is proposed. For planar design, an L-shaped monopole slot with an open-end is used as a resonator for a transistor oscillator. As a result of the simulated design of the resonator in three stages, a high Q value of 1169.84 and a high insertion loss of 49.934 dB were identified. The results of the final design and manufactured oscillator measurements confirmed that the oscillation output is greater than 7 dBm and has good phase noise characteristics of -58 dBc/Hz at 100 kHz offset. The proposed oscillator is planar and has the advantage of being directly applicable to microwave integrated circuit technology. It also has the advantage of being able to reduce its size as it can only be implemented in microstrip form without additional devices such as metal cavities and tuning screws in 3D structures, as in the case of a DRO (dielectric resonance oscillator).

TinyECCK : Efficient Implementation of Elliptic Curve Cryptosystem over GF$(2^m)$ on 8-bit Micaz Mote (TinyECCK : 8 비트 Micaz 모트에서 GF$(2^m)$상의 효율적인 타원곡선 암호 시스템 구현)

  • Seo, Seog-Chung;Han, Dong-Guk;Hong, Seok-Hie
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.18 no.3
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    • pp.9-21
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    • 2008
  • In this paper, we revisit a generally accepted opinion: implementing Elliptic Curve Cryptosystem (ECC) over GF$(2^m)$ on sensor motes using small word size is not appropriate because partial XOR multiplication over GF$(2^m)$ is not efficiently supported by current low-powered microprocessors. Although there are some implementations over GF$(2^m)$ on sensor motes, their performances are not satisfactory enough due to the redundant memory accesses that result in inefficient field multiplication and reduction. Therefore, we propose some techniques for reducing unnecessary memory access instructions. With the proposed strategies, the running time of field multiplication and reduction over GF$(2^{163})$ can be decreased by 21.1% and 24.7%, respectively. These savings noticeably decrease execution times spent in Elliptic Curve Digital Signature Algorithm (ECDSA) operations (Signing and verification) by around $15{\sim}19%$.

A Study on the Design of Small SMT Platform for Education (교육용 소형 SMT 플랫폼 설계에 관한 연구)

  • Park, Se-Jun
    • Journal of Platform Technology
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    • v.8 no.1
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    • pp.24-32
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    • 2020
  • This paper designed and manufactured a chip mounter based on 3D printer technology that can be used for educational research or sample production to disseminate chip mounter, a core technology of SMT line. A stepper motor with open loop control is used for low cost drive design. The shortcomings of the motor's vibration and disassembly caused by the use of the step motor were compensated by the Micro-Step control method. In the chip mounter experiment, the gerber file was generated on the small chip mounter, printed at the actual size, and the solder cream was printed on the HASL-treated PCB in the same manner as the sample board fabrication. As a result of the experiment, unlike the 2012 micro components, parts such as SOIC and TQFP that require correction are twice as long as the component mounting time, but it can be confirmed that they are mounted relatively accurately. In addition, as a result of repeatedly measuring the error of the initial position 10 times, it was confirmed that a relatively small error of about 0.110mm occurs.

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Slot Antenna Embedded in a PCB for Zigbee Communication (지그비 통신용 PCB 내장형 슬롯 안테나)

  • Woo, Hee-Sung;Shin, Dong-Gi;Lee, Young-Soon
    • Journal of Advanced Navigation Technology
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    • v.25 no.3
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    • pp.223-228
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    • 2021
  • In this paper, we proposed a slot-type antenna with microstrip feed embedded in a PCB for Zigbee communication (2.4 ~ 2.484 GHz). The proposed antenna is designed on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 50×65 mm2. Through simulations, trends of design parameters are analyzed and optimized, and the proposed antenna composed with three slots satisfy the frequency band. The measured impedance bandwidths (|S11| ≤ -10 dB) of fabricated antenna are 900 MHz (2 ~ 2.9 GHz) in Zigbee frequency band. In addition, the radiation pattern showed omnidirectional characteristics for E and H-planes, and the gain of antenna in Zigbee frequency band was 1.782 dBi.