• Title/Summary/Keyword: optimal processing condition

검색결과 273건 처리시간 0.023초

고속 도플러 편이 환경에서 최적 시간지연을 갖는 다중모드 모노펄스 신호처리에 관한 연구 (Study on Multi-Mode Monopulse Signal Processing System Providing Optimal Time Delay under High Doppler Condition)

  • 이재문;임재성;안희수
    • 한국군사과학기술학회지
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    • 제19권5호
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    • pp.582-589
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    • 2016
  • Multi-mode monopulse system is widely used for satellite terminal like UAV because of high tracking accuracy and low size/weight profile. In order to calculate tracking error, Multi-mode monopulse system utilizes high-order mode signal, and it should have enough C/N(carrier to noise) level therefore tracking system needs narrow band filtering of received satellite beacon signal as much as possible. However, UAV suffers for beacon frequency drift derived from Doppler effect due to satellite figure 8 movement and UAV maneuvering. Therefore wideband signal processing needs to be considered in advance for exact doppler compensation and consequent time delay. In this paper, we propose the multi-stage Digital Signal processing system for beacon signal, which could minimize the signal delay under high Doppler and low C/N condition.

수지 및 탄소섬유 함유량에 따른 C-SMC 복합재료 물성 연구 (Study on Properties of Carbon Sheet Molding Compound(C-SMC) according to Resin and Carbon Fiber Ratio)

  • 서대경;양석곤;김기영;박민기;박대규;이은하;김용태;배진석
    • 한국염색가공학회지
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    • 제32권4호
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    • pp.245-254
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    • 2020
  • The sheet molding compound composite has been applied divers section. This paper reports processing of carbon fiber reinforced thermosetting composite with diverse resins and which was composed of chopped carbon fiber (30 ~ 60 wt%). Normally the paste that the viscosity is over 15,000 cps has been used in traditional Sheet molding compound (SMC) machine. In this research, SMC machine was designed to make Carbon-sheet molding compound (C-SMC) prepreg which was composed with low viscosity resin (1,800 ~ 2,500 cps increase up to 10,000 cps after aging). In order to confirm the optimal processing condition. Mechanical strength tests including tensile test, shear test, impact test, flexural strength test were conducted on C-SMC composites. Plus we identified the correlation between the mechanical properties and prepreg processing condition (carbon ratio and applied resin).

Application of compressive sensing and variance considered machine to condition monitoring

  • Lee, Myung Jun;Jun, Jun Young;Park, Gyuhae;Kang, To;Han, Soon Woo
    • Smart Structures and Systems
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    • 제22권2호
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    • pp.231-237
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    • 2018
  • A significant data problem is encountered with condition monitoring because the sensors need to measure vibration data at a continuous and sometimes high sampling rate. In this study, compressive sensing approaches for condition monitoring are proposed to demonstrate their efficiency in handling a large amount of data and to improve the damage detection capability of the current condition monitoring process. Compressive sensing is a novel sensing/sampling paradigm that takes much fewer data than traditional data sampling methods. This sensing paradigm is applied to condition monitoring with an improved machine learning algorithm in this study. For the experiments, a built-in rotating system was used, and all data were compressively sampled to obtain compressed data. The optimal signal features were then selected without the signal reconstruction process. For damage classification, we used the Variance Considered Machine, utilizing only the compressed data. The experimental results show that the proposed compressive sensing method could effectively improve the data processing speed and the accuracy of condition monitoring of rotating systems.

다구찌 방법과 신경회로망을 이용한 사출성형 가공공정의 최적 가공조건 선정에 관한 연구 (Selecting the Optimum Condition of Injection Molding Process by the Taguchi Method and Neural Network)

  • 홍정의
    • 산업경영시스템학회지
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    • 제25권2호
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    • pp.71-76
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    • 2002
  • Defining the relationship between the quality of Injection molded parts and the process condition is very complicate because of lots of factors are involved and each factor has a non-linearity. With the development of CAE(Computer Aided Engineering) technology, the estimation of volumetric shrinkage of injection mold parts is possible by computer simulation in spite of restricted application. In this research, the Taguchi method md Neural Network are applied for finding optimal processing condition. The percent of volumetric shrinkage is compared on each case and shows neural network can be successfully applied.

A NONCONFORMING PRIMAL MIXED FINITE ELEMENT METHOD FOR THE STOKES EQUATIONS

  • Cho, Sungmin;Park, Eun-Jae
    • 대한수학회보
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    • 제51권6호
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    • pp.1655-1668
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    • 2014
  • In this article, we propose and analyze a new nonconforming primal mixed finite element method for the stationary Stokes equations. The approximation is based on the pseudostress-velocity formulation. The incompressibility condition is used to eliminate the pressure variable in terms of trace-free pseudostress. The pressure is then computed from a simple post-processing technique. Unique solvability and optimal convergence are proved. Numerical examples are given to illustrate the performance of the method.

유동경로를 이용한 축대칭 금형 형상의 실용적 ,결정 (Practical Determination of the Die Shape Using a Streamline in Axisymmetric Extrusion)

  • 이용신
    • 소성∙가공
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    • 제10권2호
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    • pp.111-114
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    • 2001
  • A new, simple method to determine the die shape using a streamline in extrusion is presented. This method assumes that a billet deforms naturally to minimize the energy input for the given process condition. Then, an optimal die shape can be determined along a streamline. Extrusion operations with two types of materials, strain-hardening material and strain-rate hardening material, are examined using this method. Predictions with the proposed method are compared with those by the previous optimizing model to show its efficiency.

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광신호 에너지 최적화를 위한 IIR 격자형 광파이버필터 설계 (Optical IIR lattice fiber filter design for optimum of optical signal energy)

  • 이채욱;김신환
    • 전자공학회논문지B
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    • 제32B권11호
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    • pp.1481-1488
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    • 1995
  • Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of IIR lattice structure, which uses coherent light sources and consists of directional couplers whose coupling coefficients are restricted between 0 and 1. Considering restrictions of directional coupler, the design formulae and condition for realibility of optical fiber filter of IIR lattice structure which makes the optimal use of optical signal energy are derived.

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압축센싱과 통계학적 기법을 적용한 회전체 시스템의 상태진단 (Application of Compressive Sensing and Statistical Analysis to Condition Monitoring of Rotating Machine)

  • 이명준;전준영;박규해;강토;한순우
    • 한국소음진동공학회논문집
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    • 제26권6_spc호
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    • pp.651-659
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    • 2016
  • Condition monitoring (CM) encounters a large data problem due to sensors that measure vibration data with a continuous, and sometimes, high sampling rate. In this study, compressive sensing approaches for condition monitoring are proposed to demonstrate the efficiency in handling a large amount of data and to improve the damage detection capability of the current condition monitoring process. Compressive sensing is a novel sensing/sampling paradigm that takes much fewer samples compared to traditional sampling methods. For the experiments a built-in rotating system was used and all data were compressively sampled to obtain compressed data. Optimal signal features were then selected without the reconstruction process and were used to detect and classify damage. The experimental results show that the proposed method could improve the data processing speed and the accuracy of condition monitoring of rotating systems.

Submerged Culture of Phellinus linteus for Mass Production of Polysaccharides

  • Lee, June-Woo;Baek, Seong-Jin;Kim, Yong-Seok
    • Mycobiology
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    • 제36권3호
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    • pp.178-182
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    • 2008
  • In order to increase the mycelial production of Phellinus linteus, which exhibits potent anticancer activity, some ingredients of the medium used to culture P. linteus were investigated. The optimal medium composition for the production of Phellinus linteus was determined to be as follows: fructose, 40 g/l; yeast extract, 20 g/l; $K_2HPO_4$, 0.46 g/l; $K_2HPO_4$, 1.00 g/l; M$MgSO_4\cdot7H_2SO$, 0.50 g/l; $FeCl_2\cdot6_2O$, 0.01 g/l; $MnCl_2\cdot4H_2O$, 0.036 g/l; $ZnCl_2$, 0.03 g/l; and $SuSO_4\cdot7H_2O$, 0.005 g/l. The optimal culture conditions were determined to be as follows: temperature, 28$^{\circ}C$; initial pH, 5.5; aeration, 0.6 vvm; and agitation, 100 rpm, respectively. Under optimal composition and conditions, the maximum mycelial biomass achieved in a 5 l jar fermentor was 29.9 g/l.

Robust seismic retrofit design framework for asymmetric soft-first story structures considering uncertainties

  • Assefa Jonathan Dereje;Jinkoo Kim
    • Structural Engineering and Mechanics
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    • 제86권2호
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    • pp.249-260
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    • 2023
  • The uncertainties involved in structural performances are of importance when the optimum number and property of seismic retrofit devices are determined. This paper proposes a seismic retrofit design framework for asymmetric soft-first-story buildings, considering uncertainties in the soil condition and seismic retrofit device. The effect of the uncertain parameters on the structural performance is used to find a robust and optimal seismic retrofit solution. The framework finds a robust and optimal seismic retrofit solution by finding the optimal locations and mechanical properties of the seismic retrofit device for different realizations of the uncertain parameters. The structural performance for each realization is computed to evaluate the effect of the uncertainty parameters on the seismic performance. The framework utilizes parallel processing to decrease the computationally intensive nonlinear dynamic analysis time. The framework returns a robust design solution that satisfies the given limit state for every realization of the uncertain parameters. The proposed framework is applied to the seismic retrofit design of a five-story asymmetric soft-first-story case study structure retrofitted with a viscoelastic damper. Robust optimal parameters for retrofitting a structure to satisfy the limit state for the different realizations of the uncertain parameter are found using the proposed framework. According to the performance evaluation results of the retrofitted structure, the developed framework is proved effective in the seismic retrofit of the asymmetric structure with inherent uncertainties.