• 제목/요약/키워드: Parameter study

검색결과 9,863건 처리시간 0.038초

미세먼지 간이측정기 현장 검사용 시험 입자 발생기 개발 및 성능 평가 (Development and performance evaluation of a test particle generator for a field inspection equipment of PM-2.5 sensors)

  • 정혁;박진수
    • 한국입자에어로졸학회지
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    • 제18권3호
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    • pp.61-68
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    • 2022
  • In this study, a fluidized bed particle generator was developed to generate an aerosol without supply of compressed air and to increase portability. It was assumed that the mixing ratio of the test particles and beads, the input amount, and the air flow rate supplied to the generator would have effect on the aerosol generation characteristics. The product of these three parameters was set as a characteristic parameter and particle generation characteristics according to the change of the characteristic parameter were observed. As a result, it was confirmed that the input amount of test particles and beads was not suitable as a characteristic parameter and a characteristic parameter expressed as a product of the mass mixing ratio and the air flowrate was newly defined. When the new characteristic parameter is applied, it can be confirmed that the total amount of particles generated from the particle generator is a function of the characteristic parameter. As a result of measuring the amount of particle generation by adjusting the characteristic parameter, it was confirmed that the performance required for the test particle generator for the field inspection equipment of PM-2.5 sensors could be satisfied.

확률론적 방법에 의한 지반조사 자료의 설계정수 산정 (Design-Parameter Computation of Subsurface Investigation Profile on Probability Method)

  • 신은철;김종인;이준철
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2003년도 봄 학술발표회 논문집
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    • pp.833-840
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    • 2003
  • The stability of structure, effectiveness of design and construction are very important factors in soil-structure design. The design-parameter is based on the test through laboratory-test and field-test. There are two ways to obtain the design-parameter. One is to through test, and the other is through relative documents and references. Recently, statistics has been used to get reliable data. In this study, Kriging method as Geostatistics and the theory of Bayesian's inference are used and the design-parameters are obtained. As the result of this study to the design-parameter is reliable and information about soil condition and soil properties in design and construction is easily found.

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Characterization of behaviors using electric pulse for phase switching operation of Ge2Sb2Te5 material

  • 이현철;최두진
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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    • pp.322-322
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    • 2016
  • Phase change memory (PCM) has attracted much attention as one of the most promising candidates for next-generation nonvolatile memory. In that regard, the purposes of the study are to propose reference of effective pulse parameter to control phase switching operation and to invest the effect of nitrogen doped in PCM materials for improved cycling stability and economic energy consumption. Switching operation of PCM is affected by electric pulse parameter and as shown in figure.1 are composed to RT(rising time), ST(setting time), FT(falling time) and the effect of these parameter was precisely investigated. Transmission electron microscope (TEM) was used to confirm fine structure and retention cycle test was conducted to confirm reliability. Finally improvement reliability and economic power consumption in quantitatively are obtainable by optimum pulse parameter and nitrogen doping in GST material. these study is related to the engineering background of other semiconductor industries and it have confirmed to possibility further applications.

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공구파손검출을 위한 시스템인식에 관한 연구 (A Study on the System Identification for Detection of Tool Breakage)

  • 사승윤
    • 한국생산제조학회지
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    • 제9권5호
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    • pp.144-149
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    • 2000
  • The demands for robotic and automatic system are continually increasing in manufacturing fields. There have been many studies to monitor and predict the system, but they have mainly focused upon measuring cutting force, and current of motor spindle, and upon using acoustic sensor, etc. In this study, time series sequence of cutting force was acquired by taking advantage of piezoelectric type tool dynamometer. Radial cutting force was obtained from it and was available for useful observation data. The parameter was estimated using PAA(parameter adaptation algorithm) from observation data. ARMA(auto regressive moving average) model was selected for system model and second order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter.

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강우상태에 의한 소수력발전소 설계변수의 변화 (The Variations of Design Parameters for Small Scale Hydro Power Plant with Rainfall Condition)

  • 박완순;이철형
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.138-141
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    • 2008
  • The effects of design parameters for small scale hydro power(SSHP) plants due to rainfall condition have been studied. The model to predict hydrologic performance for SSHP plants is used in this study. The results from analysis for rainfall conditions based on Weibull distribution show that the capacity and load factor of SSHP site had large difference between the variation of shape and scale parameter. Especially, the hydrologic performance of SSHP site due to variation of shape parameter varied more sensitive than the case of variation of scale parameter. And also, the methodology represented in this study can be used to decide the primary design specifications of SSHP sites.

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축소모형실험을 통한 사질토지반에서 Gap Parameter의 연구 (A Study on the Gap Parameter in Sand by Scale Model Test)

  • 김상환;강준구;서윤식
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 추계 학술발표회
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    • pp.1343-1349
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    • 2010
  • This paper presents the behavior of the soil based on the Gap Parameter during the Shield TBM tunnel excavation in sandy soil. This study reproduced the tunnel before and after the excavation according to the diameter of the tunnel, water ratio and depth to execute a Scaled Model Test and analyzed the behavior change of the upper soil. As a result, tunneling after for soil stress decreased was similar in all the Case. In addition, the soil stress decreased was in water ratio increases.

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수직자장하에서 원관내 자성유체의 거동에 관한 연구 (A Study on the Flow Behavior of Magnetic Fluids in a Circular Pipe with a Vertical Magnetic Field)

  • 박정우;유신오;서이수
    • 대한기계학회논문집B
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    • 제23권1호
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    • pp.25-32
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    • 1999
  • In the present paper, we theoretically analyze the flow of magnetic fluids in a circular pipe with a vertical magnetic field and investigate the magnetic response by the external magnetic field. Theoretical study through the governing equation derived by Siliomis is carried out with numerical analysis by the Gauss Elimination Method. Using polar and magnetic effect parameters, theoretical equations and distributions for the velocity, vorticity, internal angular momentum and induced magnetization as the magnetic response are shown. Especially, in the region of strong magnetic field the specific property is appeared by finding a critical magnetic effect parameter for a polar effect parameter.

Objective Bayesian multiple hypothesis testing for the shape parameter of generalized exponential distribution

  • Lee, Woo Dong;Kim, Dal Ho;Kang, Sang Gil
    • Journal of the Korean Data and Information Science Society
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    • 제28권1호
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    • pp.217-225
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    • 2017
  • This article deals with the problem of multiple hypothesis testing for the shape parameter in the generalized exponential distribution. We propose Bayesian hypothesis testing procedures for multiple hypotheses of the shape parameter with the noninformative prior. The Bayes factor with the noninformative prior is not well defined. The reason is that the most of the noninformative prior can be improper. Therefore we study the default Bayesian multiple hypothesis testing methods using the fractional and intrinsic Bayes factors with the reference priors. Simulation study is performed and an example is given.

체적비구배를 이용한 섬유강화 적층 복합재의 열하중에 의한 층건력 감소에 대한 연구 (A Study on Reduction of Thermal Interlaminar Forces of Fiber-Reinforced Laminate Composites Using Volume Fraction Gradient)

  • 최덕기;신종한
    • 대한기계학회논문집A
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    • 제24권5호
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    • pp.1115-1122
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    • 2000
  • This paper addresses an application of a fiber volume fraction gradients to reduce the interlaminar forces of fiber reinforced composites subjected to thermal loadings. The degree of the reduction in the interlaminar forces may be expressed by introducing a new parameter, so called, the interlaminar force parameter. Several cases of stacking sequences and models for fiber volume fraction gradients prove the availability of the new parameter which is defined in this study.

원관내 자성유체의 Rheology 특성에 관한 연구 (A Study on the Rheology Characteristics of Magnetic Fluids in a Circular Pipe)

  • 전언찬;박정우;김태호;김수용
    • 한국기계가공학회지
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    • 제7권2호
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    • pp.38-44
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    • 2008
  • In the present paper, we theoretically analyze the flow of magnetic fluids in a circular pipe with a vertical magnetic field and investigate the magnetic response by the external magnetic field. Theoretical study through the governing equation derived by Siliomis is carried out with numerical analysis by the Gauss Elimination Method. Using polar and magnetic effect parameters, theoretical equations and distributions for the velocity, apparent viscosity as the magnetic response are shown. Especially, in the region of strong magnetic field the specific property is appeared by finding a critical magnetic effect parameter for a polar effect parameter.

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