• Title/Summary/Keyword: 산포해석

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Dispersion of Particle Pulse in Human Lung Airway (인체기관지내의 입자펄스 확산 실험)

  • 이진원;이동엽;추경호
    • Journal of Biomedical Engineering Research
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    • v.19 no.5
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    • pp.511-518
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    • 1998
  • In order to develop the aerosol bolus technique which is thought to be a potential tool for probing geometries or abnormalities of small airways, an experimental system of measuring fast time variations of particle concentration in the inhaled and exhaled breathing air was developed. The system generates monodisperse sebacic acrid particles of 1 micron size and 1.2 of geometric standard deviation in high concentration of $10^8$ particles/cc, delivers a short pulse of particles at the controlled instant during inhalation using a solenoid valve, and measures the fast change of particle concentration in using the laser light scattering. Successful operation of the generator and the measuring system was confirmed by smooth concentration profiles in inhalation. It was also confirmed that maintaining a constant breathing rate is essential to stable outputs and any disturbance in flow rate near the mode (maximum concentration) induces a large number of spurious peaks in the exhalation. Experimental data without strict control of breathing flow rate showed a substantial amount of scatter. The measured results showed an improvement in scatter over the existing results. When compared with theoretical predictions from 1-D convective diffusion equation and other experiments, general characteristics of dispersion for several penetration depths showed a good agreement, but there exists some difference in absolute values, which is attributed to the difference in body conditions. Improvements are needed in the theory, especially in relation to correcting for the effect of breathing flow rate.

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An Empirical Study on the Economical Competition Factors of Internet Retailers (인터넷 소매상의 경제적 경쟁요인에 관한 실증연구)

  • 이수정;남순해;고석하
    • Proceedings of the Korea Society of Information Technology Applications Conference
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    • 2002.11a
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    • pp.3-13
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    • 2002
  • 고석하 등(2002)은 인터넷 소매상이 상품 품목의 명목 가격과 배송료를 이용해서 고객의 일회 총 구매 비용을 조절한다는 것을 밝혔다. 고석하 등(2002)은 같은 내용의 상품 조합을 인터넷 시장에서 구매하기 위한 비용과 전통 시장에서 구매하기 위한 비용을 비교하였다. 분석 결과, 그 교호작용과 함께, 상품 종류와 일회 구매액/가격의 크기의 두 요소가 인터넷 시장의 전통 시장에 대한 총 구매비용 할인율의 변동의 약 60%내지 80%를 설명할 수 있다는 것을 보여주었다. 한편, 구매액/가격은 인터넷 시장에서의 해당 산포도(전통 시장의 그것에 대비한)에는 거의 영향을 미31지 못하며, 상품의 종류도 산포도에는 할인율에서와 같이 큰 영향을 미치지 않았다. 인터넷 시장의 가격이나 구매비용 산포도는 상품 특성이나 구매액 크기 이외의 다른 요인에 의해서 주로 영향을 받는 것으로 나타났다. 따라서, 본 논문에서는 가격 요인 이외의 경제적 경쟁요인에 관한 실증연구로서, 2002년 6월 17일부터 20일까지, 소프트웨어, PC와 주변기기, 휴대폰, 가전제품, CD, 화장품, 그리고 책의 7가지 산업 전문 쇼핑몰과 종합 쇼핑몰을 대상으로, 인터넷 시장에서 수행되고 있는 경제적인 비가격 경쟁요인에 관한 실증 조사를 실시하였다. 조사 결과, 인터넷 시장에서 수행되고 있는 경제적인 비가격 경쟁요인은 매우 다양하며, 상품별로도 다른 특성을 보이고 있는 것으로 밝혀졌다. 인터넷 소매상의 경제적인 비가격 경쟁요인은 크게 배송료 면제와 배송료 외 인센티브 제도로 구분된다. 본 논문에서는 경제적인 비가격 경쟁요인의 모든 경우의 수를 고려할 수 있도록, 코드표를 작성하여 정리하고 분석하였다.기호로 인식하였다. 실험결과, 표준패턴을 음표와 비음표의 두개의 그룹으로 나누어 인식함으로써 DP 매칭의 처리 속도를 개선시켰고, 국소적인 변형이 있는 패턴과 특징의 수가 다른 패턴의 경우에도 좋은 인식률을 얻었다.리되고 이원화된 코드체계와 데이터 형태의 이질화를 통일하는 방법으로 데이터웨어하우스 시스템을 제시하였다. 결국 병원에서 데이터웨어하우스 시스템의 구축은 임상, 연구, 교육의 유기적 순환관계를 정립하여 지식의 순환적 고리인 수집, 공유, 확산, 재창출을 지속적 유지할 수 있는 인프라를 구축해 준다. 반면 상이한 정보들간의 충돌과 이에 따른 해석의 오류로 잘못된 의사결정을 위한 정보를 제공할 수 있고 기초정보의 접근 및 추출의 유용성에 의해서 정보유출에 대한 문제가 한계점으로 나타났다.로세스 개선을 위해서 무엇을 정말로 필요로 하는지를 밝힘으로써, 한국 소프트웨어 산업의 현실적인 특수성을 고려한 소프트웨어 프로세스 평가와 개선 모델의 개발을 위한 기초적인 자료를 제공할 것으로 예상된다. 또한, 본 연구 결과는, 우리나라 소프트웨어 조직들이 실제로 무엇을 필요로 하는지를 밝힘으로써, 우리나라의 소프트웨어 산업을 육성하기 위한 실효성 있는 정책 입안을 위한 기초 자료를 제공할 것으로 예상된다.를 검증하려고 한다. 협력체계 확립, ${\circled}3$ 전문인력 확보 및 인력구성 조정, 그리고 ${\circled}4$ 방문보건사업의 강화 등이다., 대사(代謝)와 관계(關係)있음을 시사(示唆)해 주고 있다.ble nutrient (TDN) was highest in booting stage (59.7%); however no sig

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Shape Optimization and Reliability Analysis of the Dovetail of the Disk of a Gas Turbine Engine (가스터빈엔진 디스크의 도브테일 형상 최적화와 신뢰도 해석)

  • Huh, Jae-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.4
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    • pp.379-384
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    • 2014
  • The most critical rotating parts of a gas turbine engine are turbine blades and disc, given that they must operate under severe conditions such as high turbine inlet temperature, high speeds, and high compression ratios. Owing to theses operating conditions and high rotational speed energy, some failures caused by turbine disks and blades are categorized into catastrophic and critical, respectively. To maximize the margin of structural integrity, we aim to optimize the vulnerable area of disc-blade interface region. Then, to check the robustness of the obtained optimized solution, we evaluated structural reliability under uncertainties such as dimensional tolerance and fatigue life variant. The results highlighted the necessity for and limitations of optimization which is one of deterministic methods, and pointed out the requirement for introducing reliability-based design optimization which is one of stochastic methods. Thermal-structural coupled-filed analysis and contact analysis are performed for them.

Study on the Prediction Technique of Vehicle Performance using Parameter Analysis (파라미터 해석을 통한 차량 성능 예측 기법 연구)

  • Kim, Ki-Chang;Kim, Chan-Mook;Kim, Jin-Taek
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.647-653
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    • 2009
  • Taguchi parameter design is an approach to reducing performance variation of quality characteristic value in products and processes. Taguchi has used SN (Signal to Noise) ratio to achieve the appropriate set of operating conditions where variability around target is low in the Taguchi parameter design. This paper describes the prediction technique of vehicle performance using parameter analysis to reduce man hour and test development period as well as to achieve stable NVH performance. Design engineer could efficiently decide the design variable using parameter analysis database in early design stage. These improvements can reduce the time needed to develop better vehicles.

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Selection Technique of Filter based on Analysis for Variables of Dual Polarized Radar (이중편파레이더 변수 분석 기반 필터 선정 기법)

  • Lee, Keon Haeng;Lim, Sanghun;Jang, Bong Joo;Hyun, Myung Suk;Lee, Dong Ryul
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.517-517
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    • 2015
  • 레이더에 수신된 신호는 신호처리기를 통해 자료의 해석시 불필요한 지형에코를 제거하는 과정을 거친다. 신호처리기의 필터는 레이더의 기종에 따라 다르나, 일반적으로 도플러 속도나 스펙트럼 폭의 값에 따라 지형에코를 제거하며, 이 값들에 따라 번호를 부여하여 필터를 선택적으로 이용할 수 있도록 되어 있다. 본 연구에서는 국토교통부에서 운영하고 있는 비슬산 강우레이더와 소백산 강우레이더의 필터번호에 따른 반사도의 빈도 영역 그래프, 반사도-차등반사도의 빈도 산포도, 반사도와 차등반사도의 평균 및 표준편차를 통해 적정 필터를 선정하고자 하였다. 이 때, 지형에코와 기상에코의 제거 정도 확인을 위해 레이더 관측반경 50 km를 기준으로 비교를 수행하였다. 그 결과, 1번 필터 이후에는 필터에 따른 큰 변화가 없어 1번 필터를 사용하는 것이 기상에코를 보존하면서 지형에코를 제거하는 효과가 가장 좋은 것으로 판단되었다.

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Numerical Simulation on Dispersion of Fume Micro-Particles by Particle Suction Flows in Laser Surface Machining (입자 석션유동에 따른 레이저 표면가공의 마이크로 흄 오염입자 산포 특성 해석연구)

  • Kyoungjin Kim
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.4
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    • pp.1-6
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    • 2023
  • In CO2 laser surface machining of plastic films in modern display manufacturing, scattering of fume particles could be a major source of well-recognized film surface contamination. This computational fluid dynamics research investigates the suction air flow patterns over a film surface as well as the dispersion of micron-sized fume particles with low-Reynolds number particle drag model. The numerical results show the recirculatory flow patterns near laser machining point on film surface and also over the surface of vertical suction slot, which may hinder the efficient removal of fume particles from film surface. The dispersion characteristics of fume particles with various particle size have been tested systematically under different levels of suction flow intensity. It is found that suction removal efficiency of fume particles heavily depends on the particle size in highly nonlinear manners and a higher degree of suction does not always results in more efficient particle removal.

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Improvement of Assembly Characteristics of a Lens Module in a Mobile Phone Camera using Finite Element Analysis (유한요소해석을 사용한 휴대폰 카메라용 렌즈모듈의 결합특성 개선)

  • Moon, Yang-Ho;Moon, Jae-Ho;Lyu, Min-Young;Park, Keun
    • Elastomers and Composites
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    • v.44 no.4
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    • pp.366-372
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    • 2009
  • The present study covers the optimal design for a lens module in a mobile phone camera by using the design of experiments (DOE) and finite element (FE) analysis. FE analyses are performed to investigate the effect of design parameters on the amount of torque required to assemble a barrel and a housing part. The DOE approach is then performed to optimize the design parameters in order to maintain an appropriate torque with less variations.

Bayesian Reliability Analysis Using Kriging Dimension Reduction Method(KDRM) (크리깅 기반 차원감소법을 이용한 베이지안 신뢰도 해석)

  • An, Da-Un;Choi, Joo-Ho;Won, Jun-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.3
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    • pp.275-280
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    • 2008
  • A technique for reliability-based design optimization(RBDO) is developed based on the Bayesian approach, which can deal with the epistemic uncertainty arising due to the limited number of data. Until recently, the conventional REDO was implemented mostly by assuming the uncertainty as aleatory which means the statistical properties are completely known. In practice, however, this is not the case due to the insufficient data for estimating the statistical information, which makes the existing RBDO methods less useful. In this study, a Bayesian reliability is introduced to take account of the epistemic uncertainty, which is defined as the lower confidence bound of the probability distribution of the original reliability. In this case, the Bayesian reliability requires double loop of the conventional reliability analyses, which can be computationally expensive. Kriging based dimension reduction method(KDRM), which is a new efficient tool for the reliability analysis, is employed to this end. The proposed method is illustrated using a couple of numerical examples.

A Feasibility Study of Seawater Injection Nozzle Prototype Development by Using 3D Printing (3D 프린팅을 이용한 해수분사용 노즐 시제품 개발의 가능성 연구)

  • Yoon, Seok-Tea;Park, Jong-Chun;Cho, Yong-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.3
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    • pp.51-57
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    • 2021
  • The seawater cooling system of naval ships is installed to remove the toxic substances generated by CBR (Chemical, Biological, and Radiological) warfare and reduce the infrared signature of naval ships from outside the hull. The dispersion range of the nozzle is determined according to the injection pressure of seawater and the nozzle type. Therefore, it is necessary to select the appropriate injection pressure and design the optimal nozzles to increase the seawater dispersion area and maximize the efficiency of the cooling system. In this study, the applying feasibility of 3D printing technology to produce an injection nozzle for the seawater cooling system was examined. To this end, the extruded plastic specimens were fabricated by 3D printing, and the physical properties of the specimens were estimated through tensile testing. After this, the strain and stress of the nozzle as a function of the pressure were simulated by applying the estimated results to the finite element analysis. The finite element analysis results showed that the nozzle remained within the elastic range at the optimal pressure. The nozzle was estimated to be structurally stable, and the possibility of this study was confirmed.

Study on the Prediction Technique of Vehicle Performance Using Parameter Analysis (파라미터 해석을 통한 차량 성능 예측 기법 연구)

  • Kim, Ki-Chang;Kim, Chan-Mook;Kim, Jin-Taek
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.11
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    • pp.995-1000
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    • 2010
  • With the development of the auto industry, the automobile manufacturers demand to shorten development period and reduce the cost. Compared with the traditional method, applying the virtual prototype is more economical. This paper presents a method for parameters sensitivity analysis and optimizing the performance of vehicle noise and vibration. The existing design processes were repeatedly analyzed with a focus on vehicle performance to decide the design parameters of dimension, thickness, mounting type of body and chassis systems in the vehicle development period. This paper describes the prediction technique of vehicle performance using L18 orthogonal array layout, quality deviation analysis and parameter sensitivity analysis for robust design. This paper analyzed the performance correlation equation through the frequency and sensitivity database according to a design factor change. The new concept is that the performance prediction is possible without repeated activities of test and analysis. This paper described the parameter analysis applications such as bush dynamic stiffness and bush void direction of rear suspension. Design engineer could efficiently decide the design variable using parameter analysis database in early design stage. These improvements can reduce man hour and test development period as well as to achieve stable NVH performance.