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  • Title/Summary/Keyword: Proper variables

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The Characteristics of Iron(Fe) Floc Formation for Treatment of Acid Mine Drainage (산성 광산 배수의 처리를 위한 철(Fe) 성분의 플럭 형성 특성)

  • Song, Kun-Ho;Lee, Kwang-Rae
    • Journal of Industrial Technology
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    • v.33 no.A
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    • pp.89-92
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    • 2013
  • The characteristics of floc formation of the iron(Fe) ions was studied for developing the process treating the acid mine drainage. The metal ions in aqueous solution oxidized with oxygen in air, which generated hydrogen ion and lowered the pH of the aqueous solution. The iron(Fe) ions were formed into flocs by the acid-base reaction with the added Ca(OH)2 for the neutralizing the solution. There were several variables affecting the formation, size and color of floc; whether air was present or not, air feeding rate, oxidizing time, concentration of Ca(OH)2, the acid-base reaction time of the iron(Fe)Ca(OH)2. For proper formation of the $iron(Fe)-Ca(OH)_2$ flocs and developing the floc treating system, the control variables mentioned above should be considered.

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Vibration Analysis of Rotating Cantilever Plates with Arbitrary Orientation Angle (임의의 자세를 갖는 외팔평판의 진동해석)

  • Kim, Sung-Kyun;Yoo, Hong-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.8
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    • pp.1331-1337
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    • 2003
  • Linearized equations of motion for the vibration analysis of rotating cantilever plates with arbitrary orientation angle are derived in the present work. Two in-plane stretch variables are introduced to be approximated. The use of the two in-plane stretch variables enables one to derive the equations of motion which include proper motion-induced stiffness variation terms. The equations of motion are transformed into dimensionless forms in which dimensionless parameters are identified. The effects of the dimensionless parameters on the modal characteristics of rotating cantilever plates are investigated through numerical study. The natural frequency loci veering along with the associated mode shape variations, which occur while the rotating speed increases, are also presented and discussed.

A Study on Dynamic Characteristics of Welding Current and Arc Length At GMAW (GMA용접에서 용접전류와 아크 길이의 동특성에 관한 연구)

  • Lee, Tae-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.14 no.1
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    • pp.15-21
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    • 2011
  • Welding variables and conditions in gas metal arc welding (GMAW) effect on the quality and productivity of the weld, extensive research efforts have been made to analyze the effect of the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the characteristics of the power supply, wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

Application of Bayesian Networks for Flood Risk Analysis (베이지안 네트워크를 적용한 홍수 위험도 분석)

  • SunWoo, Woo-Yeon;Lee, Kil-Seong;Chung, Eun-Sung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.467-467
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    • 2012
  • As the features of recent flood are spatially concentrated, loss of life and property increase by the impact of climate change. In addition to this the public interest in water control information is increased and socially reasonable justification of water control policy is needed. It is necessary to estimate the flood risk in order to let people know the status of flood control and establish flood control policy. For accurate flood risk analysis, we should consider inter-relation between causal factors of flood damage. Hence, flood risk analysis should be applied to interdependence of the factors selected. The Bayesian networks are ideally suited to assist decision-making in situations where there is uncertainty in the data and where the variables are highly interlinked. In this research, to provide more proper water control information the flood risk analysis is performed using the Bayesian networks to handle uncertainty and dependency among 13 specific proxy variables.

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A Study on Dynamic Characteristics of Welding voltage and Welding Current At GMAW (GMA 용접에서 전압과 전류의 동특성에 관한 연구)

  • Kim, Myun-Hee;Choi, Young-Geun;Lee, Moon-Hwan
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.2
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    • pp.207-213
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    • 2001
  • Welding variables and condition in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the chararcteristic equations of the power supply. wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

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Identifying Factors Affecting Dental University Hospitals' Profitability (치과대학병원 수익성에 영향을 미치는 요인 분석)

  • Lee, Ji-Hoon;Kim, Seong-Sik
    • Korea Journal of Hospital Management
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    • v.26 no.2
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    • pp.17-26
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    • 2021
  • Purposes: This study aims to identify factors affecting dental university hospitals' profitability and understand recent their business condition. Methodology: Data from 2016 to 2019 was collected from financial statement, public open data in 8 dental university hospitals. For the study, multiple regression test with stepwise selection was applied. Findings: First of all, 9 out of 19 independent variables were selected by stepwise selection. As a result of multiple regression test with selected independent variables and the dependent variable(operating profit margin ratio), the factors affecting hospitals' profitability were the number of dental unit chair, hospital location, debt ratio, total capital turnover ratio, employment cost rate, material cost rate, management expense rate, the number of patient per a dentist. Practical Implication: To improve dental university hospitals' profitability, hospitals specifically analysis and manage their cost such as employment, material and management cost and seek effectiveness by managing the proper number of patient per a dentist.

Advanced Congestion Control Algorithm Using Change of Queue Length in ATM ABR Service (ATM ABR 서비스에서 큐 길이 변화를 이용한 개선된 폭주 제어 알고리즘)

  • 김체훤;강현철;곽지영;남지승
    • Proceedings of the IEEK Conference
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    • 2000.06c
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    • pp.109-112
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    • 2000
  • The EPRCA(Enhanced Proportional Rate Control Algorithm) is one of the explicit rate control algorithm recommended by the ATM forum. EPRCA algorithm is using only two threshold to buffer change is not considered for calculating ER value. In this paper to cover the shortage, two more variables are added for considering increase of buffer quantity. So calculating proper ER would avoid before getting into the congestion situation. To analysis the affect, EPRCA and proposed algorithm are compared through simulation by analysis of change of buffer length and ACR change

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An Analytical Evaluation of the Ductility of Reinforced High-Strength Concrete Columns (고강도 철근 콘크리트 기둥 부재의 연성해석)

  • 박훈규;장일영
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.463-466
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    • 1999
  • Ductility is an important consideration in the design of reinforced high-strength concrete. Therefore, this research investigate the ductile behavior of rectangular high-strength concrete columns like as bridge piers with confinement steel. The effect on the ductility of axial load, lateral reinforcement ratio, longitudinal reinforcement ratio, shear ratio, and compressive strength of concrete were investigated analytically using layered section analysis. As the results, it was proposed the proper relationship between ductility and variables and formulated into equations.

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Simulated Annealing Algorithm for Optimum Design of Space Truss Structures (입체 트러스구조물의 최적설계를 위한 SA기법)

  • 정제원;박효선
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.102-109
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    • 1999
  • Two phase simulated annealing algorithm is presented as a structural optimization technique and applied to minimum weight design of space trusses subjected to stress and displacement constraints under multiple loading conditions. Univariate searching algorithm is adopted for automatic selection of initial values of design variables for SA algorithm. The proper values of cooling factors and reasonable stopping criteria for optimum design of space truss structures are proposed to enhance the performance of optimization process. Optimum weights and design solutions are presented for two well-blown example structures and compared with those reported in the literature.

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Characterization of Chemical Vapor Condensation Reactor for Parylene-N Thin Film Deposition

  • Lee, Jong-Seung;Yeo, Seok-Ki;Park, Chin-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.897-900
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    • 2003
  • Chemical vapor condensation (CVC) reactor was investigated for the deposition of Parylene-N thin films as the passivation layer for organic light emitting diodes (OLEDs). Several gas inlet manifold designs were tested to improve the deposition rate and its uniformity, and it was found that proper inlet design is crucial to get the desired film properties. Process characterization was also performed with the modified inlets to optimize the process variables.

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