• Title/Summary/Keyword: continuous method

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A Continuous Scanning Laser Doppler Vibrometer for Mode Shape Analysis (모드형상분석을 위한 연속 스캐닝 레이저 도플러 진동측정기)

  • Park, Kyi-Hwan;Choi, Ji-Eun;La, Jong-Pil;Wang, Sem-Yung;Kyoung, Yong-Soo;Kim, Koung-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.5
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    • pp.734-741
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    • 2003
  • This paper addresses the vibration mode shape Measurement technique utilizing a Continuous Scanning Laser Doppler Vibrometer (CSLDV). The continuous scanning capability is added to the conventional discrete Laser Doppler Vibrometer by reflecting the laser beams on the surface of the object using two oscillating mirrors. The bow scanning resulted from the proposed scanning method is eliminated by feedback control. The velocity output signal from the CSLDV is modulated to give the spatial velocity distribution in terms of coefficients which are obtained from the Fast Fourier Transformation of the time dependent velocity signal. Using the Chebyshev series from, the analysis of the vibration mode shape techniques for straight line scanning and 2 dimensional scanning are presented and discussed. The performance of the proposed SLDV is presented using the experimental results of the vibration mode shape of a cantilever and plate

Characterization of Continuous Cast Cu-Ni-Si Alloys (연속주조된 Cu-Ni-Si계 합금의 특성평가)

  • Lee, Jung-Il;Cho, Hoon
    • Journal of the Korean Society for Heat Treatment
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    • v.25 no.6
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    • pp.292-298
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    • 2012
  • In this study, Cu-2.5at.%Ni-1at.%Si alloys were fabricated by horizontal continuous casting system to improve the electrical conductivity and mechanical properties of Cu-Ni-Si alloy. Withdrawing speed was changed with 50, 100, 150 and 200 mm/min for the optimum manufacturing condition. Microstructure was observed using OM, FE-SEM and TEM. Electrical conductivity was measured by 4-point probe method and mechanical properties were tested. A horizontal continuous cast thin slab had sound macro and micro structures with partly crystallized structures. Electrical resistivity decreased with increasing annealing temperature from 250 to $850^{\circ}C$, with increasing annealing temperature The maximum hardness and tensile strength were Hv 130, 610 MPa at $550^{\circ}C$, respectively. With changing withdrawing speed from 50 to 150 mm/min, hardness, tensile strength, yield strength and elongation were Hv 60-65, 210-230 MPa, 65-75 MPa and 40-50%, respectively.

Korean Continuous Speech Recognition Using Discrete Duration Control Continuous HMM (이산 지속시간제어 연속분포 HMM을 이용한 연속 음성 인식)

  • Lee, Jong-Jin;Kim, Soo-Hoon;Hur, Kang-In
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.1
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    • pp.81-89
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    • 1995
  • In this paper, we report the continuous speech recognition system using the continuous HMM with discrete duration control and the regression coefficients. Also, we do recognition experiment using One Pass DP method(for 25 sentences of robot control commands) with finite state automata context control. In the experiment for 4 connected spoken digits, the recognition rates are $93.8\%$ when the discrete duration control and the regression coefficients are included, and $80.7\%$ when they are not included. In the experiment for 25 sentences of the robot control commands, the recognition rate are $90.9\%$ when FSN is not included and $98.4\%$ when FSN is included.

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Optimum Design of Greenhouse Structures Using Continuous and Discrete Optimum Algorithms (연속 및 이산화 최적알고리즘에 의한 단동온실구조의 최적설계)

  • Park, Choon-Wook;Lee, Jong-Won;Lee, Hyun-Woo;Lee, Suk-Gun
    • Journal of Korean Association for Spatial Structures
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    • v.5 no.4 s.18
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    • pp.61-70
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    • 2005
  • In paper the discrete optimum design program was developed using the continuous and discrete optimum algorithms based on the SUMT and genetic algorithms. In this paper, the objective function is the weight of structures and the constraints are limits state design limits method. The design variables are diameter and thick of steel pipe. Design examples are given to show the applicability of the optimum design using the continuous and discrete optimum algorithms based on the SUMT and genetic algorithms of this study.

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Chip Shape Control using AE Signal in Pure Copper Turning (순동선삭가공에서 AE 신호를 이용한 칩 형상 제어)

  • Oh, Jeong Kyu;Kim, Pyeong Ho;Koo, Joon Young;Kim, Duck Whan;Kim, Jeong Suk
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.4
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    • pp.330-336
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    • 2014
  • The continuous chip generated in cutting process deteriorates workpiece, tool, and machine tool system. It is necessary to treat this continuous chip in ductile material machining condition for stable cutting. This paper deals with the chip control method using acoustic emission(AE) signal in pure copper turning operation. AE raw signals, root mean square(RMS) signals and wavelet transformed signals measured in turning process are introduced to analysis for chip patterns. With analysis of AE signals, it is obtained that the produced chip patterns are correlated with the specified AE signals which are transformed by fuzzy pattern algorithm. By this experimental investigation, the chip patterns can be classified at significant level in pure copper machining process and controlled from continuous chips to reduced-length stable chips.

Multivariable Nonlinear Model Predictive Control of a Continuous Styrene Polymerization Reactor

  • Na, Sang-Seop;Rhee, Hyun-Ku
    • 제어로봇시스템학회:학술대회논문집
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    • 1999.10a
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    • pp.45-48
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    • 1999
  • Model predictive control algorithm requires a relevant model of the system to be controlled. Unfortunately, the first principle model describing a polymerization reaction system has a large number of parameters to be estimated. Thus there is a need for the identification and control of a polymerization reactor system by using available input-output data. In this work, the polynomial auto-regressive moving average (ARMA) models are employed as the input-output model and combined into the nonlinear model predictive control algorithm based on the successive linearization method. Simulations are conducted to identify the continuous styrene polymerization reactor system. The input variables are the jacket inlet temperature and the feed flow rate whereas the output variables are the monomer conversion and the weight-average molecular weight. The polynomial ARMA models obtained by the system identification are used to control the monomer conversion and the weight-average molecular weight in a continuous styrene polymerization reactor It is demonstrated that the nonlinear model predictive controller based on the polynomial ARMA model tracks the step changes in the setpoint satisfactorily. In conclusion, the polynomial ARMA model is proven effective in controlling the continuous styrene polymerization reactor.

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The Experiences of Pump-driven Continuous Venovenous Hemofiltration Therapy in Pediatric Patients (소아에서 펌프를 이용한 지속적 정정맥 여과법을 시행한 경험 3례)

  • Lim Yean-Jung;Hahn Hye-Won;Lee Byung-Sun;Park Young-Seo
    • Childhood Kidney Diseases
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    • v.6 no.2
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    • pp.251-258
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    • 2002
  • We report the experiences of pump-driven continuous venovenous hemofiltration therapy in three children with acute renal failure. The all three patients required mechanical ventilation and needed the support of vasopressors. Renal replacement therapy was needed to meet the metabolic and fluid balance, but intermittent hemodialysis and peritoneal dialysis were not feasible because of hemodynamic instability and concurrent infection. We instituted pump-driven continuous venovenous hemofiltratlon (CVVH), and immediate improvement of pulmonary edema and successful removal of retained fluid were observed. Urea clearance also was satisfactory. During the filter running time, significant thromboembolic event or rapid drop of systemic blood pressure were absent. We concluded that the CVVH is an effective and safe method of renal support for critically ill pediatric patient.

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A Study on the Fabrication Method of Mold for 7 inch LCD-BLU by continuous microlens 200μm (연속마이크로렌즈 200μm 적용 7인치 LCD-BLU 금형개발)

  • Kim, J.S.;Ko, Y.B.;Min, I.K.;Yu, J.W.;Heo, Y.M.;Yoon, K.H.;Hwang, C.J.
    • Transactions of Materials Processing
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    • v.16 no.1 s.91
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    • pp.42-47
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    • 2007
  • LCD-BLU is one of kernel parts of LCD and it consists of several optical sheets: LGP, light source and mold frame. The LGP of LCD-BLU is usually manufactured by etching process and forming numerous dots with $50\sim300{\mu}m$ diameter on the surface. But the surface of the etched dots of LGP is very rough due to the characteristics of the etching process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched dot patterned LGP, optical pattern with continuous microlens was designed using optical simulation CAE. Also, a mold with continuous micro-lens was fabricated by UV-LiGA reflow process and applied to 7 inch size of navigator LCD-BLU in the present study.

Derivation of work-hardening exponent using continuous indentation technique (연속압입시험법을 이용한 가공경화지수의 유도)

  • Jeon, Eun-Chae;Ahn, Jeong-Hoon;Kwon, Dong-Il
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.256-261
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    • 2000
  • In this study, we derived work-hardening exponent using continuous indentation test technique. Continuous indentation test technique is a powerful method to evaluate mechanical properties, such as hardness, modulus, ${\sigma}-{\varepsilon}$ curves and etc. It has many merits conventional indentation test has. The relationship between true stress and mean contact pressure and between strain and indentation depth were derived. While the indenter pushes the materials, the region around the indenter is deflected elastically. It is called elastic deflection. And pile-up phenomenon related to plastic deformation around the indenter increased the contact depth, and sink-in phenomenon decreases. So we calibrated contact depth change by considering elastic deflection and pile-up/sink-in. Using calibrated contact depth we redefined the relationship between true stress and mean contact pressure and between strain and contact depth. Through these relationship we could derive work-hardening exponent by analyzing load-depth curves. And it showed good agreement with tensile test results.

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Effects of Continuous Antagonistic Muscle Strengthening and Evjenth-Hamberg Stretching on the Pressure Pain Threshold of Forward Head Posture Subjects

  • Koo, Ja Pung;Choi, Wan Suk;Park, Ju Hyun
    • Journal of International Academy of Physical Therapy Research
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    • v.7 no.1
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    • pp.956-964
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    • 2016
  • The purpose of this study was to identify the effects of continuous muscle strengthening applied to the antagonist of the sternocleidomatoid, upper trapezius, and pectoralis major, which are the shortened muscles of forward head posture(FHP) subjects, and Evjenth-Hamberg stretching(EHS) applied to the shortened muscles on changes in pressure pain threshold(PPT). Twenty subjects were divided into the continuous antagonist strengthening(CAS) group(n=10) and the EHS group(n=10), and each group performed its respective exercise three times a week for a six week period. The results were as follows: The comparison of changes in PPT within each group before and after the treatment showed a statistically significant difference(p<.05) according to the treatment period and a statistically significant difference according to the treatment period and method(p<.05). While the comparison of the tests of between subjects effects between the groups did not show a statistically significant difference, the CAS group exhibited better effects. The above results suggest that the combined application of CAS and EHS generates better effects on changes in PPT than the single application of EHS. Given that stretching and muscle strengthening exercises even for the short research period of six weeks could change the PPT, continuous exercises and a correct postural habit for a longer period of time are likely to help prevent chronic pain and correct FHP.