• Title/Summary/Keyword: convergence test

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Study on Environmental Resistance of Railway Transponder Tag for Wayside Installation (철도교통 트랜스폰더 태그의 선로변 설치를 위한 내환경성 연구)

  • Kim, Hye Yun;Park, Sungsoo;Yang, Youngoo;Lee, Seung Won;Youm, Ki Jung;Lee, Jae-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.6
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    • pp.948-953
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    • 2015
  • In this paper, we studied the environmental requirements for the railway transponder system. The transponder system is comprised of a reader installed beneath the train, a tag installed on the track, and a portable programmer. Among them, the transponder tag should be designed to withstand harsh environments, such as wide operating temperature range, mechanical shock and vibration, etc. To validate stable and reliable service under railway conditions, we carried out environmental test for transponder tag. We then installed the tags on the Honam high-speed test line.

The Study of Accommodation Assessment in Binocular Functional Test (양안시검사의 조절평가 연구)

  • Cho, Young-Rae;Park, Hyun-Ju
    • Journal of Korean Ophthalmic Optics Society
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    • v.12 no.1
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    • pp.61-67
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    • 2007
  • The binocular functional test was performed in test of both accommodation and convergence. The balance of accommodation and convergence was important. Objects were 100 adults in 18-36 years old ages. The used apparatus was vision tester(Shinnippon VT10)and visual chart(Shinnippon CT30). Accommodative lag test by fused cross cylinder were that in case of high 39.0%, in case of low 14.0%. Negative relative accommodation were that in case of high 23.0%, in case of low 38.0%. Positive relative accommodation were that in case of high 29.0%, in case of low 23.0%. In 18% were case of low accommodation.

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Research on the NOx Reduction Rate of Diesel Vehicle for Euro-6 (Euro-6 대응 경유 차량의 NOx 저감율 분석 연구)

  • Kang, Minkyung;Kwon, Seokjoo;Seo, Youngho
    • Journal of Institute of Convergence Technology
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    • v.7 no.1
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    • pp.15-18
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    • 2017
  • As emission gas regulation of deisel vehicles is strengthened to Euro-6, It becomes difficult to deal with NOx regulated value mainly by EGR without additional after-treatment system. In addition, RDE(Real Driving Emissions) test will be introduced after september 2017. Therefore, It is essential to develop the after-treatment of diesel vehicles which reduce NOx emissions. It is possible to use DOC, DPF, LNT or DOC, DPF and SCR as a after-treatment system for reducing NOx. However, It is expected that the SCR will be applied widely because LNT alone does not have sufficient NOx purification efficiency. In this study, It tried to analyze the efficiency of reducing NOx emissions during the mode test by attaching a NOx sensor to test vehicle. As a result, It was confirmed that NOx emissions was significantly reduce through the after-treatment system from engine. And the NOx reduction efficiency of SCR was about 4.5 times better than DOC, DPF.

Comparison and Evaluation of Two-part Wedge Analysis for Reinforced Slopes with Centrifuge Test (보강사면(補强斜面)에 대한 Centrifuge Test와 Two-part Wedge 해석(解析)의 비교평가(比較評價))

  • Seo, In-Shik;Lee, Chin;Kim, Byung-Tak
    • Journal of the Korean Society of Industry Convergence
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    • v.2 no.2
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    • pp.35-39
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    • 1999
  • Results of two-part wedge analysis and centrifuge test executed by Zornberg et al. were compared for geotextile-reinforced slope stability. For two-part wedge analysis results of two cases, a frictional case considering internal friction of soil as interwedge friction and a nonfrictional case not considering, were also compared and evaluated. The analysis was based on limit equilibrium and two-part wedge was divided into slices as many as the number of geotextiles to obtain a maximum tension distribution mobilized in reinforcements. A significant observation was that the distribution was a triangular shape with maximum tension of geotextile at a transit point of interwedge. The number of geotextiles and failure surface of frictional case were reasonable and more comparable to results of the centrifuge tests than those of nonfrictional case. Therefore it can be said that two-part wedge analysis is recommendable for design analysis of reinforced slopes if an interwedge angle is regarded to be an angle of internal friction in soil.

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Case study comparisons of computational fluid dynamics modeling versus tracer test to evaluate the hydraulic efficiency of clearwell (정수지 내 추적자 실험과 CFD(전산유체역학)의 상관관계 분석)

  • Kim, Tae-Kyun;Choi, Young-June;Jo, Young-Mahn
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.5
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    • pp.635-642
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    • 2011
  • Hydraulic efficiency was a vital component in evaluating the disinfection capability of clearwell. Current practice evaluates these system based on the tracer test only. In this paper, CFD(Computational Fluid Dynamics) was applied on the clearwell for alternating or supplementing the tracer test. The baffle factor derived from the CFD modeling closely matched the values obtained from full scale tracer testing. And, for suggesting proper numerical model in clearwell; the turbulence model, discretization scheme, convergence criteria were investigated through separate simulation runs. The model validation was conducted by comparing the simulated data with experimental data. In the turbulence model, the realizable ${\kappa}-{\varepsilon}$ model and the standard ${\kappa}-{\varepsilon}$ model were found to be more appropriate than RNG ${\kappa}-{\varepsilon}$ model. The residuals of convergence criteria should be used as not $10^{-3}$ but $10^{-4}$ or $10^{-5}$. In discretization scheme, the difference of simulated values in 1st, 2nd, 3rd upwind scheme was found to be insignificant. Moreover, the result of this study suggest that CFD modeling can be a reliable alternative to tracer testing for evaluating the hydraulic efficiency.

An Experimental Study on the Characteristic of Thermal Performance according to Feed Water Conditions to of Vacuum Membrane Distillation Module using PVDF Hollow Fiber (PVDF 중공사막을 이용한 진공 막 증류 모듈의 공급수 조건에 따른 열성능 특성에 관한 실험적 연구)

  • Joo, Hongjin;Kwak, Heeyoul
    • Journal of Korean Society of Water and Wastewater
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    • v.31 no.4
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    • pp.339-346
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    • 2017
  • In this study, thermal performance test of VMD module was performed, prior to the construction of the demonstration plant using the vacuum membrane distillation (VMD) module of the capacity of $400m^3/day$ and to the commercialization of the VMD module. For the thermal performance test, the experimental equipment of capacity of $2m^3/day$ was constructed. The permeate flux test and thermal performance test according to feed water conditions such as temperature and flow rate were conducted. The VMD module used in the study was manufactured by ECONITY Co., LTD with PVDF hollow fiber membrane. As a result, the Performance Ratio (PR) of the VMD module showed the maximum value of 0.904 under the condition of feed water temperature of $75^{\circ}C$ and flow rate of $8m^3/h$. PR value of the VMD module using PVDF hollow fiber membrane showed linearly increasing relationship with feed water temperature and flow rate. Also, The permeate flux of the VMD module was analyzed to have maximum value of 18.25 LMH and the salt rejection was 99.99%.

A Study on Weapon Systems Acquisition for the Use of Modeling & Simulation(M&S) (무기체계 획득을 위한 모델링 및 시뮬레이션(M&S) 활용에 관한 연구)

  • Lee, Pil-Jung;Lee, Young-Uk
    • Convergence Security Journal
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    • v.11 no.3
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    • pp.11-17
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    • 2011
  • The acquisition of weapons systems test and evaluation in the early stages of the acquisition process as a source of data used for modeling and simulation are being actively encouraged. Thus, in the reliability of weapon systems acquisition can be called the most important part, and M&S to apply for this test reliability and accuracy of the assessment can provide, test time and cost savings, the pre-and post-test predictions and available data can provide. In this study, theoretical study of M&S to acquire weapon systems used for the importance of M&S, acquired the characteristics of the model, utilization for weapon systems acquisition, and weapon systems acquisition review for an effective utilization of M&S tries to find out.

A Durability Evaluation of Remanufactured Industrial Hydraulic Pump and Solenoid Valve (산업용 유압펌프 및 솔레노이드 밸브 재제조품의 내구성 평가)

  • Lee, Kyu-Chang;Park, Sang-Jin;Son, Woo-Hyun;Jeon, Chang-Su;Mok, Hak-Soo
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.5
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    • pp.537-546
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    • 2021
  • Remanufacturing is one of the most important resource recycling technology in response to resource depletion and environmental pollution. Domestic remanufacturing industry don't invigorate compared to other advanced countries because of low price and reliability of remanufactured product. In this study, remanufactured hydraulic pump and solenoid valve were evaluated durability by accelerated life test. In order that standard remanufacturing process was developed by core analysis and failure mode and effect analysis. And cores were remanufactured by standard remanufacturing process. For accelerated life test, the evaluation item and criteria were deduced by results of FMEA, reliability standards and enterprise interior criteria. To evaluate durability of remanufactured product, the remanufactured hydraulic pump and solenoid valve were evaluated performance after accelerated life test and the results were satisfied with criteria. This study showed that remanufactured products have a similar level of durability to new products by definition of remanufacturing.

A Study on the Bonding Strength of Titanium Artificial Teeth for Baking Dental Ceramics using Micro-arc Oxidation Surface Treatment Technology (마이크로 아크 산화 표면처리 기술을 활용한 치과도재 소부용 티타늄 인공치아 결합강도 연구)

  • Song, Jong-Beop;Park, Jong-Min;Kim, Jong-Soon;Jung, Hyo-Kyung;Choi, Won-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.2_2
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    • pp.309-314
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    • 2022
  • The bonding strength [ISO22674] test was conducted by firing a dedicated ceramic powder on the surface of the dental titanium material treated with micro-arc oxidation. In the test group, an average result value of 34.34 MPa was obtained, and in the control group, a result value of 21.53 MPa was obtained. The bonding strength of the test group was higher than that of the control group by 12.81 MPa, resulting in a 37% improvement in durability of the dental artificial tooth ceramic restoration.

Analysis of Charge and Discharge Characteristics of Heavy Duty Electric Commercial Vehicle Batteries (중대형 전기 상용차 배터리의 주행중 충방전 특성 분석)

  • Song, Jingeun;Cha, Junepyo
    • Journal of Institute of Convergence Technology
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    • v.11 no.1
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    • pp.19-23
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    • 2021
  • These days, sales of battery electric vehicles have been rapidly increasing due to the strict CO2 regulations. However, since it take too long to measure the energy economy of electric vehicles, it has been required to improve the procedure of energy economy measurement. In order to improve this problem, the present study analyzed the battery charge/discharge pattern according to the changes in battery SOC (state of charge). In general, the energy economy test is started with a battery SOC charged to 100 %. However, it was identified that when the battery is fully charged, it can actually be charged over the 100 % (e.g., 100.5 %). This can induce errors in the energy economy measurement. Therefore, the present study recommend to start the test at SOC 99.9 %. The regenerative braking was partly restricted for the SOC over 90 %. This made it difficult to estimate the overall energy economy of the electric vehicle. However, it was identified that there was no change in the battery charge/discharge characteristics under the SOC 90 %. Therefore, the energy economy test can be shortened by predicting the overall energy economy through a short mileage test.