• Title/Summary/Keyword: Optimization of Operation Conditions

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Optimization of Polishing Conditions for Anodized Inner Surfaces in Large Hydraulic Devices (아노다이징 처리된 대형 유압장치의 내면에 대한 연마 조건의 최적화)

  • Choi, Su-Hyun;Cho, Young-Tae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.7
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    • pp.14-21
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    • 2019
  • Large-diameter hydraulic devices such as the hydraulic reservoir in aircraft that serves to balance the hydraulic pressure in the various hydraulic devices in the cabin and to store hydraulic oil are operated by the internal piston systems. However, since this operates in an environment with high temperature and humidity, it may cause the inner surface to flake during its operation. Therefore, an anodizing surface treatment is applied to improve the corrosion resistance, abrasion resistance, and smooth operation. However, anodizing increases the surface roughness. Accordingly, the polishing process that improves the surface roughness after anodizing is important. However, the existing polishing process is performed manually, which results in an inefficient process. Therefore, in this study, we selected the optimum polishing conditions for effective polishing using the experimental design to improve the polishing process for the $Al_2O_3$ film that forms after anodization. Through experiments, we confirmed that the surface uniformity after polishing was superior as the feed rate was slower when the same polishing time had been applied.

Development of a Deep Learning-based Long-term PredictionGenerative Model of Wind and Sea Conditions for Offshore Wind Farm Maintenance Optimization (해상풍력단지 유지보수 최적화 활용을 위한 풍황 및 해황 장기예측 딥러닝 생성모델 개발)

  • Sang-Hoon Lee;Dae-Ho Kim;Hyuk-Jin Choi;Young-Jin Oh;Seong-Bin Mun
    • Journal of Wind Energy
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    • v.13 no.2
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    • pp.42-52
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    • 2022
  • In this paper, we propose a time-series generation methodology using a generative adversarial network (GAN) for long-term prediction of wind and sea conditions, which are information necessary for operations and maintenance (O&M) planning and optimal plans for offshore wind farms. It is a "Conditional TimeGAN" that is able to control time-series data with monthly conditions while maintaining a time dependency between time-series. For the generated time-series data, the similarity of the statistical distribution by direction was confirmed through wave and wind rose diagram visualization. It was also found that the statistical distribution and feature correlation between the real data and the generated time-series data was similar through PCA, t-SNE, and heat map visualization algorithms. The proposed time-series generation methodology can be applied to monthly or annual marine weather prediction including probabilistic correlations between various features (wind speed, wind direction, wave height, wave direction, wave period and their time-series characteristics). It is expected that it will be able to provide an optimal plan for the maintenance and optimization of offshore wind farms based on more accurate long-term predictions of sea and wind conditions by using the proposed model.

Optimization for the Antibacterial Activity of Konjak Jelly using Evolutionary Operation-Factorial Design Technique (Evolutionary Operation-Factorial Design Technique를 이용한 곤약의 항균활성 최적화)

  • Lee, Nan-Hee;Choi, Won-Seok;Choi, Ung-Kyu
    • The Korean Journal of Food And Nutrition
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    • v.31 no.2
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    • pp.272-277
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    • 2018
  • This research was conducted to elucidate the optimum conditions for the antibacterial activity of konjak jelly using the evolutionary operation-factorial design technique. In the first set of experiments, concentration of a coagulation agent, soaking liquid, and temperature of water were set to 0.4%, $0.6{\times}10^{-2}N$, and $65^{\circ}C$ as a central point, respectively. The highest antibacterial activity was acquired at E21, in which the number of bacteria was 1.25 log cfu/g. Because the code of changes in the main effect was (-), it could be decided that the central point of the first set was not the optimum point. Although antibacterial activity in the second set was improved, the values of the main effect were higher than that of changes in the mean effect. The central point of third set was concentration of coagulation agent 0.8%, concentration of soaking liquid $1.0{\times}10^{-2}N$, and temperature of water $65^{\circ}C$. It was found that the antibacterial activity of central point in the third set was highest among all the tested set. Further, all the necessary conditions were appropriate to reach the optimum condition. The antibacterial activity of the central point in third set was more than 1,000 times higher than that of E11, in first set.

A Study on the Operating Characteristics of Variable Speed Pump for In-Line Booster Pumping Station (직결식 변속펌프의 운전 방안에 대한 연구)

  • Park, Jong-Moon;Choi, Sung-Il;Roh, Hyung-Woon;Suh, Sang-Ho;Kim, Sang-Gyun
    • 유체기계공업학회:학술대회논문집
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    • 2001.11a
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    • pp.191-196
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    • 2001
  • In the systems with largely pipe head loss, variable speed pumps are generally used because substantial energy saving can be expected from such systems by controlling pump speed and also they offer simpler maintenance and operational ease even in conditions where abrupt changes In flow rate and head can occur. The invertor or the fluid coupling system are mainly adopted to control the rotating speed. In this paper, operating conditions at Migum pressing pump station(5 stage), where the fluid coupling system was the first installed for KOWACO, are investigated and analysed so that information thus gained can be usefully employed in the efficient operation of variable speed pump in new installations of in-line booster pumping station.

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Optimization of ultrasonification of slaughter blood for protein solubilization

  • Jeon, Yong-Woo
    • Environmental Engineering Research
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    • v.20 no.2
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    • pp.163-169
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    • 2015
  • In this study, we attempted to solubilize protein in slaughter blood (SB) using ultrasonic technology. The application of ultrasonic technology can make enzymatic degradation of SB more effective, which has no comparable alternative for treatment. The SB was homogenized by grinding it for 10 minutes at 10,000 rpm as a pretreatment for preventing its clotting, and then ultrasonic treatment was attempted to solubilize protein in SB. To maximize the efficiency of ultrasonic treatment for SB, the optimum condition of ultrasonic frequency (UF) was determined to be 20 kHz. To optimize the operation conditions of ultrasonification with 20 kHz of frequency, we used response surface methodology (RSM) based on ultrasonic density (UD) and ultrasonification time (UT). The solubilization rate (SR) of protein (%) was calculated to be $101.304-19.4205X_1+0.0398X_2+7.9411X_1{^2}+0.0001X_2{^2}+0.0455X_1X_2$. From the results of the RSM study, the optimum conditions of UD and UT were determined at 0.5 W/mL and 22 minutes, respectively, and SB treated under these conditions was estimated to have a 95% SR. Also, experimentally, a 95.53% SR was observed under same conditions, accurately reflecting the theoretical prediction of 95%.

Online railway wheel defect detection under varying running-speed conditions by multi-kernel relevance vector machine

  • Wei, Yuan-Hao;Wang, You-Wu;Ni, Yi-Qing
    • Smart Structures and Systems
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    • v.30 no.3
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    • pp.303-315
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    • 2022
  • The degradation of wheel tread may result in serious hazards in the railway operation system. Therefore, timely wheel defect diagnosis of in-service trains to avoid tragic events is of particular importance. The focus of this study is to develop a novel wheel defect detection approach based on the relevance vector machine (RVM) which enables online detection of potentially defective wheels with trackside monitoring data acquired under different running-speed conditions. With the dynamic strain responses collected by a trackside monitoring system, the cumulative Fourier amplitudes (CFA) characterizing the effect of individual wheels are extracted to formulate multiple probabilistic regression models (MPRMs) in terms of multi-kernel RVM, which accommodate both variables of vibration frequency and running speed. Compared with the general single-kernel RVM-based model, the proposed multi-kernel MPRM approach bears better local and global representation ability and generalization performance, which are prerequisite for reliable wheel defect detection by means of data acquired under different running-speed conditions. After formulating the MPRMs, we adopt a Bayesian null hypothesis indicator for wheel defect identification and quantification, and the proposed method is demonstrated by utilizing real-world monitoring data acquired by an FBG-based trackside monitoring system deployed on a high-speed trial railway. The results testify the validity of the proposed method for wheel defect detection under different running-speed conditions.

2011, The Analysis Operating Characteristics of Photovoltaic System in Naju-city (2011년 나주시 태양광 발전 시스템의 운전특성)

  • Hyun, Jeong-Woo;Lee, Nam-Jin;Cha, In-Su;Kim, Dong-Mook;Choi, Jeong-Sik
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.359-363
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    • 2011
  • Building-integrated photovoltaics(BIPV)are increasingly incorporate into new domestic and industrial buildings as a proncipal or ancillary source of electrical power, and are on of the fastest growing segments of the photovoltaic industry. This paper presents operational features analysis and PCS(Power conversion System) factors of grid-connected 30kW BIPV on library of Dongshin University. The data consisted of insolation, Temperature, solar-cell performance and inverter performance are collected by IVIsion web monitoring system and analyzed. The analyzed data gave this paper effect elements of optimal operation.

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Dynamic Configuration and Operation of District Metered Areas in Water Distribution Networks

  • Bui, Xuan-Khoa;Kang, Doosun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.147-147
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    • 2021
  • A partition of water distribution network (WDN) into district metered areas (DMAs) brings the efficiency and efficacy for water network operation and management (O&M), especially in monitoring pressure and leakage. Traditionally, the DMA configurations (i.e., number, shape, and size of DMAs) are permanent and cannot be changed occasionally. This leads to changes in water quality and reduced network redundancy lowering network resilience against abnormal conditions such as water demand variability and mechanical failures. This study proposes a framework to automatically divide a WDN into dynamic DMA configurations, in which the DMA layouts can self-adapt in response to abnormal scenarios. To that aim, a complex graph theory is adopted to sectorize a WDN into multiscale DMA layouts. Then, different failure-based scenarios are investigated on the existing DMA layouts. Here, an optimization-based model is proposed to convert existing DMA layouts into dynamic layouts by considering existing valves and possibly placing new valves. The objective is to minimize the alteration of flow paths (i.e., flow direction and velocity in the pipes) while preserving the hydraulic performance of the network. The proposed method is tested on a real complex WDN for demonstration and validation of the approach.

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Risk-Informed Optimization of Operation and Procedures for Korea Research Reactor (리스크정보 최적화를 통한 국내 연구용원자로의 안전성 향상)

  • Lee, Yoon-Hwan;Jang, Seung-Cheol
    • Journal of the Korean Society of Safety
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    • v.37 no.2
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    • pp.43-53
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    • 2022
  • This paper describes an attempt to improve and optimize the operational safety level of a domestic research reactor by conducting a probabilistic safety assessment (PSA) under full-power operating conditions. The PSA was undertaken to assess the level of safety at an operating research reactor in Korea, to evaluate whether it is probabilistically safe and reliable to operate, and to obtain insights regarding the requisite procedural and design improvements for achieving safer operation. The technical objectives were to use the PSA to identify the accident sequences leading to core damage, and to conduct sensitivity analyses based thereon to derive insights regarding potential design and procedural improvements. Based on the dominant accident sequences identified by the PSA, eight types of sensitivity analysis were performed, and relevant insights for achieving safer operation were derived. When these insights were applied to the reactor design and operating procedure, the risk was found to be reduced by approximately ten times, and the safety was significantly improved. The results demonstrate that the PSA methodology is very effective for improving reactor safety in the full-power operating phase. In particular, it is a highly suitable approach for identifying the deficiencies of a reactor operating at full power, and for improving the reactor safety by overcoming those deficiencies.

Modeling of Microalgal Photosynthetic Activity Depending on Light Intensity, Light Pathlength and Cell Density (빛의 세기, 투과거리 및 세포농도에 따른 미세조류의 광합성 활성 모델링)

  • Yun, Yeong-Sang;Park, Jong-Mun
    • KSBB Journal
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    • v.14 no.4
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    • pp.414-421
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    • 1999
  • The influenced of light intensity, cell density, and light pathlength on photosynthetic activity of Chlorella vulgaris were investigated. Since the light respon curve varied according to reaction conditions, the parameters estimated from nonlinear regression were proved to be apparent and could not be applied to various situations. The light response model incorporating the light penetration through the microalgal suspension was developed based upon the spatial distribution of the photosynthetic activity. This model showed a good agreement with experimental data at different cell densities and light intensities. Using the model the effects of cell density and light pathlenth were simulated and some dicussions about optimization of operation conditions of photobioreactors were carried out. Concludingly, the developed model can be useful for predicting microalgal photosynthesis and for determining the optimal operating conditions.

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