• Title/Summary/Keyword: Low-end System

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Cutting Force Measuring System Using the Load Cell for a Milling Process (로드셀을 이용한 밀링 가공시의 절삭력 측정시스템)

  • Kang, E. G.;Park, S. J.;Lee, S. J.;Kwon, H. D.
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.6
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    • pp.133-140
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    • 2001
  • This paper suggests another system for a cutting force measuring tool in a milling process. Generally, tool dynamometer is taken into account for the most appropriate cutting force measuring tool in the analysis of cutting mechanism. However, high price and limited space make it difficult to be in-situ system for controllable milling process. Although an alternative method using AC current of servo-motor has been suggested, it is unsuitable for cutting force control because of small upper frequency limit and noise. The cutting force measuring system is composed of two load cells placed between the moving table bracket and the nut flange part of ballscrew. It has many advantages such as low cost and wide range measurement than tool dynamometer because of the built-in moving table and the low cost load cell. The static and dynamic model of the measuring system using imbeded load cell is introduced. Various Experiments are carried out to validate both models. By comparing the cutting forces from a series of end milling experiments on the tool dynamometer and the system developed in this paper, the accuracy of the cutting force measuring system is verified. Upper frequency limit is measured by the experiment of dynamic characteristics.

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Front-End Module of 18-40 GHz Ultra-Wideband Receiver for Electronic Warfare System

  • Jeon, Yuseok;Bang, Sungil
    • Journal of electromagnetic engineering and science
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    • v.18 no.3
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    • pp.188-198
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    • 2018
  • In this study, we propose an approach for the design and satisfy the requirements of the fabrication of a small, lightweight, reliable, and stable ultra-wideband receiver for millimeter-wave bands and the contents of the approach. In this paper, we designed and fabricated a stable receiver with having low noise figure, flat gain characteristics, and low noise characteristics, suitable for millimeter-wave bands. The method uses the chip-and-wire process for the assembly and operation of a bare MMIC device. In order to compensate for the mismatch between the components used in the receiver, an amplifier, mixer, multiplier, and filter suitable for wideband frequency characteristics were designed and applied to the receiver. To improve the low frequency and narrow bandwidth of existing products, mathematical modeling of the wideband receiver was performed and based on this spurious signals generated from complex local oscillation signals were designed so as not to affect the RF path. In the ultra-wideband receiver, the gain was between 22.2 dB and 28.5 dB at Band A (input frequency, 18-26 GHz) with a flatness of approximately 6.3 dB, while the gain was between 21.9 dB and 26.0 dB at Band B (input frequency, 26-40 GHz) with a flatness of approximately 4.1 dB. The measured value of the noise figure at Band A was 7.92 dB and the maximum value of noise figure, measured at Band B was 8.58 dB. The leakage signal of the local oscillator (LO) was -97.3 dBm and -90 dBm at the 33 GHz and 44 GHz path, respectively. Measurement was made at the 15 GHz IF output of band A (LO, 33 GHz) and the suppression characteristic obtained through the measurement was approximately 30 dBc.

The Current-Position Cascade PID Control of Delta-type Parallel Robot (델타 로봇의 전류-위치 Cascade PID 제어)

  • Paek, Dong-Hee;Kim, Yeong-Dae;Cho, Whang
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.2
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    • pp.273-284
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    • 2020
  • This paper proposes a method of designing and controlling delta robots with low-cost DC motors, which are widely used in the automation process. Simulation was performed by interpreting the mechanics and dynamics of the delta robot, and based on this analysis, low-cost DC motor was selected. Experiments were conducted to obtain characteristic values of motors and the current-position cascade control system was designed and implemented. In order to verify the feasibility of the proposed system, the experiment to check that the end-effector of the delta robot follows the target path was progressed. Through the experiment, the limitations of using low-cost motors were overcome by designing compensation algorithms and the performance of the position control was verified.

An Improved Decoding Scheme of LCPC Codes (LCPC 부호의 개선된 복호 방식)

  • Cheong, Ho-Young
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.4
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    • pp.430-435
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    • 2018
  • In this paper, an improved decoding scheme for low-complexity parity-check(LCPC) code with small code length is proposed. The LCPC code is less complex than the turbo code or low density parity check(LDPC) code and requires less memory, making it suitable for communication between internet-of-things(IoT) devices. The IoT devices are required to have low complexity due to limited energy and have a low end-to-end delay time. In addition, since the packet length to be transmitted is small and the signal processing capability of the IoT terminal is small, the LCPC coding system should be as simple as possible. The LCPC code can correct all single errors and correct some of the two errors. In this paper, the proposed decoding scheme improves the bit error rate(BER) performance without increasing the complexity by correcting both errors using the soft value of the modulator output stage. As a result of the simulation using the proposed decoding scheme, the code gain of about 1.1 [dB] was obtained at the bit error rate of $10^{-5}$ compared with the existing decoding method.

Study of Via-Typed Air-Gap for Logic Devices Applications below 45 nm Node

  • Kim, Sang-Yong;Kim, Il-Soo;Jeong, Woo-Yang
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.4
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    • pp.131-134
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    • 2011
  • Back-end-of-line using ultra low-k (ULK; k < 2.5) has been required to reduce resistive capacitance beyond 45 nmtechnologies, because micro-processing units need higher speed and density. There are two strategies to manufacture ULK inter-layer dielectric (ILD) materials using an air-gap (k = 1). The former ULK and calcinations of ILD degrade the mechanical strength and induce a high cost due to the complication of following process, such as chemical mechanical polishing and deposition of the barrier metal. In contrast, the air-gap based low-k ILD with a relatively higher density has been researched on the trench-type with activity, but it has limited application to high density devices due to its high air-gap into the next metal layer. The height of air-gap into the next metal layer was reduced by changing to the via-typed air-gap, up to about 50% compared to that of the trench-typed air-gap. The controllable ULK was easily fabricated using the via-typed air-gap. It is thought that the via-type air-gap made the better design margin like via-patterning in the area with the dense and narrow lines.

Theoretical and Experimental Evaluation of R502 Alternatives in Low Temperature Applications (저온용 R502 대체 냉매의 이론 및 실험적 평가)

  • Kwon, S.L.;Park, Y.B.;Jung, D.S.;Kim, C.B.;Kang, D.J.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.4
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    • pp.654-666
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    • 1995
  • R502 has been extensively used as a working fluid in transport refrigerating vehicles and low temperature refrigerating machines but is to be phased out by the end of 1995 due to ozone layer depletion problem. In this study, both theoretical cycle analysis and experiments were carried out to examine the best substitutes for R502. Theoretical results indicate that the alternatives available in the market today may replace R502 without significant changes in the system without suction line heat exchanger(SLHX). When the system contains a SLHX, however, COPs of the alternatives increase up to approximately 15~20% than those without the SLHX. But simultaneously, the discharge temperatures of the compressor also increrease significantly with the SLHX. Actual test results obtained from the experiment with a transport vehicle's refrigerator indicate the similar trend as those of the theoretical results. Especially, HFCs and their mixtures show lower discharge temperature than those of R502, which is one of the desirable features. Further research is needed to study the effect of the SLHX on the performance of the real machine as well as on the oil return for reliability of the system.

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A Finger Crease Pattern Identification Algorithm Utilizing Clustering Method (클러스터링 기법을 이용한 손가락 마디지문 식별 알고리즘)

  • 주일용;안장용;최환수
    • Proceedings of the IEEK Conference
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    • 2000.11d
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    • pp.247-250
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    • 2000
  • This paper proposes a finger crease pattern identification algorithm utilizing a clustering method. The algorithms has been developed for the use of biometric person identification system. Since the finger crease pattern may be well-imaged utilizing low cost imaging devices such as low-end CCD camera with LED lighting, the feasibility of commercialization of the algorithm and the system utilizing the algorithm may be well justified if the finger crease pattern is a reasonable choice for the biometric feature. In this paper, we exploit this possibility and show the potential of using the finger crease pattern as a feature for biometric person identification.

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Implementation of ZigBee Home Control System (ZigBee 스펙에 의한 가전 제어 구현)

  • Park, Woo-Chool;Kim, Young-Ho;Kim, Dae-Whan
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.228-230
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    • 2004
  • ZigBee Alliance is a network designed for low-cost and very low-power short-range wireless communications. The ZigBee Alliance is a consortium formed by several leading semiconductor and industrial manufactures, and end users. One of the tasks of this organization is the definition of the networking support and applications profiles that will use IEEE Std 802.15.4-compliant transceivers. In the case of IEEE Std 802.15.4, the ZigBee Alliance is an organization that has led the development of the upper layers, through the definition of application profiles. We have implemented ZigBee home control system, however we have not fully implemented. Because of the ZigBee is not perfectly standarded. We will have to implement according to ZigBee Specifications.

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Low-temperature Phase Equilibria in $TiO_2$-rich Region of the System BaO-$TiO_2$ (BaO-$TiO_2$계의 $TiO_2$-rich 조성 영역에서의 저온 상평형)

  • 박정호;김호기
    • Journal of the Korean Ceramic Society
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    • v.38 no.3
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    • pp.245-250
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    • 2001
  • BaO-TiO$_2$계의 TiO$_2$-rich 조성영역에 대한 상평형 관계를 완전 고상 반응법을 통하여 재평가하였다. 출발 시료로는 이 계의 end-member인 BaO와 TiO$_2$(rutile)를 이용하였다. 각 시료들은 대기 중에서 800~120$0^{\circ}C$의 온도구간에서 선택적으로 열처리되었다. 열처리된 시편들은 상온까지 급냉 처리되었으며, 상 분석은 X-ray 회절 분석을 통하여 이루어졌다. 연구결과에서 BaTi$_2$O$_{5}$(1:2)상과 BaTi$_{5}$O$_{11}$(1:5)상이 저온에서의 고상 반응을 통해서도 쉽게 형성될 수 있음을 알 수 있었으며, 각 저온 상들의 불변 반응 온도를 열처리 온도에 따른 상 분석을 통하여 확인할 수 있었다.

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Analysis and Measurement of Current Harmonics Due to Non-linear Load in Low Voltage System (저압 시스템에서 비선형 부하의 사용에 따른 전류 고조파 해석 및 측정)

  • Kim, Jong-Gyeom;Lee, Eun-Ung
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.12
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    • pp.601-608
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    • 2001
  • The ever increasing density of adjustable speed drives(ASD) device with non-linear operating characteristics has been to put tremendous harmonic stress on end user's electrical application. All ASD controllers which employ solid state power devices cause harmonic currents in the source side line. This paper describes harmonic problems for use of ASD. In order to investigate the effect of harmonics caused by using of nonlinear load at the low voltage system, we fixed up simple load model and measured the voltage and current waveforms. Measurement results show that additional operation of linear load at the parallel bus with nonlinear load such as ASD is helpful to the reduction of harmonic influence.

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