• Title/Summary/Keyword: uncertainty measurement

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Design optimization of tuned mass damper for the vibration of hydraulic pipeline (유압 배관 진동 감쇠를 위한 동조질량감쇠기 최적 설계)

  • Kim, Chan-Kyeong;Baek, Seunghun
    • The Journal of the Acoustical Society of Korea
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    • v.40 no.1
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    • pp.64-72
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    • 2021
  • This paper carried out the optimal design of Tuned Mass Damper (TMD) to attenuate the vibrational energy of pipeline subjected to fluid movement. Under the uncertainty of the vibration source and the specification of a pipeline system, an adaptive approach to design TMD is suggested. A surrogate pipeline system model was designed using MATLAB, and the optimal design method was developed based on the surrogate pipe model. The developed optimization method was validated using Finite Element (FE) model in ANSYS Workbench. And the TMD was designed to account for measurement error and installed on the industrial pipeline system. It showed that the pipeline vibrational amplitude was reduced by 95 % after installing the TMD.

Determination of more than 500 Pesticide Residues in Hen Eggs by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Gas Chromatography-Tandem Mass Spectrometry (GC/MS/MS)

  • Golge, Ozgur;Liman, Turan;Kabak, Bulent
    • Food Science of Animal Resources
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    • v.41 no.5
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    • pp.816-825
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    • 2021
  • This study aims to validate a fast method of simultaneous analysis of 365 LCamenable and 142 GC-amenable pesticides in hen eggs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively, operating in multiple reaction monitoring (MRM) acquisition modes. The sample preparation was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction. Key method performance parameters investigated were specificity, linearity, limit of quantification (LOQ), accuracy, precision and measurement uncertainty. The method was validated at two spiking levels (10 and 50 ㎍/kg), and good recoveries (70%-120%) and relative standard deviations (RSDs) (≤20) were achieved for 92.9% of LC-amenable and 86.6% of GC-amenable pesticide residues. The LOQs were ≤10 ㎍/kg for 94.2% of LC-amenable and 92.3% of GC-amenable pesticides. The validated method was further applied to 100 egg samples from caged hens, and none of the pesticides was quantified.

Neutronic simulation of the CEFR experiments with the nodal diffusion code system RAST-F

  • Tran, Tuan Quoc;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.54 no.7
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    • pp.2635-2649
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    • 2022
  • CEFR is a small core-size sodium-cooled fast reactor (SFR) using high enrichment fuel with stainless-steel reflectors, which brings a significant challenge to the deterministic methodologies due to the strong spectral effect. The neutronic simulation of the start-up experiments conducted at the CEFR have been performed with a deterministic code system RAST-F, which is based on the two-step approach that couples a multi-group cross-section generation Monte-Carlo (MC) code and a multi-group nodal diffusion solver. The RAST-F results were compared against the measurement data. Moreover, the characteristic of neutron spectrum in the fuel rings, and adjacent reflectors was evaluated using different models for generation of accurate nuclear libraries. The numerical solution of RAST-F system was verified against the full core MC solution MCS at all control rods fully inserted and withdrawn states. A good agreement between RAST-F and MCS solutions was observed with less than 120 pcm discrepancies and 1.2% root-mean-square error in terms of keff and power distribution, respectively. Meanwhile, the RAST-F result agreed well with the experimental values within two-sigma of experimental uncertainty. The good agreement of these results indicating that RAST-F can be used to neutronic steady-state simulations for small core-size SFR, which was challenged to deterministic code system.

Target alignment method of inertial confinement fusion facility based on position estimation

  • Lin, Weiheng;Zhu, Jianqiang;Liu, Zhigang;Pang, Xiangyang;Zhou, Yang;Cui, Wenhui;Dong, Ziming
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3703-3716
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    • 2022
  • Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments' results, thereby improving the success rate of the experiments.

Structural damage detection in presence of temperature variability using 2D CNN integrated with EMD

  • Sharma, Smriti;Sen, Subhamoy
    • Structural Monitoring and Maintenance
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    • v.8 no.4
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    • pp.379-402
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    • 2021
  • Traditional approaches for structural health monitoring (SHM) seldom take ambient uncertainty (temperature, humidity, ambient vibration) into consideration, while their impacts on structural responses are substantial, leading to a possibility of raising false alarms. A few predictors model-based approaches deal with these uncertainties through complex numerical models running online, rendering the SHM approach to be compute-intensive, slow, and sometimes not practical. Also, with model-based approaches, the imperative need for a precise understanding of the structure often poses a problem for not so well understood complex systems. The present study employs a data-based approach coupled with Empirical mode decomposition (EMD) to correlate recorded response time histories under varying temperature conditions to corresponding damage scenarios. EMD decomposes the response signal into a finite set of intrinsic mode functions (IMFs). A two-dimensional Convolutional Neural Network (2DCNN) is further trained to associate these IMFs to the respective damage cases. The use of IMFs in place of raw signals helps to reduce the impact of sensor noise while preserving the essential spatio-temporal information less-sensitive to thermal effects and thereby stands as a better damage-sensitive feature than the raw signal itself. The proposed algorithm is numerically tested on a single span bridge under varying temperature conditions for different damage severities. The dynamic strain is recorded as the response since they are frame-invariant and cheaper to install. The proposed algorithm has been observed to be damage sensitive as well as sufficiently robust against measurement noise.

Wireless sensor network design for large-scale infrastructures health monitoring with optimal information-lifespan tradeoff

  • Xiao-Han, Hao;Sin-Chi, Kuok;Ka-Veng, Yuen
    • Smart Structures and Systems
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    • v.30 no.6
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    • pp.583-599
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    • 2022
  • In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.

A Dynamic OHT Routing Algorithm in Automated Material Handling Systems (자동화 물류시스템 내 차량 혼잡도를 고려한 무인운반차량의 동적 경로 결정 알고리즘)

  • Kang, Bonggwon;Kang, Byeong Min;Hong, Soondo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.45 no.3
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    • pp.40-48
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    • 2022
  • An automated material handling system (AMHS) has been emerging as an important factor in the semiconductor wafer manufacturing industry. In general, an automated guided vehicle (AGV) in the Fab's AMHS travels hundreds of miles on guided paths to transport a lot through hundreds of operations. The AMHS aims to transfer wafers while ensuring a short delivery time and high operational reliability. Many linear and analytic approaches have evaluated and improved the performance of the AMHS under a deterministic environment. However, the analytic approaches cannot consider a non-linear, non-convex, and black-box performance measurement of the AMHS owing to the AMHS's complexity and uncertainty. Unexpected vehicle congestion increases the delivery time and deteriorates the Fab's production efficiency. In this study, we propose a Q-Learning based dynamic routing algorithm considering vehicle congestion to reduce the delivery time. The proposed algorithm captures time-variant vehicle traffic and decreases vehicle congestion. Through simulation experiments, we confirm that the proposed algorithm finds an efficient path for the vehicles compared to benchmark algorithms with a reduced mean and decreased standard deviation of the delivery time in the Fab's AMHS.

The Sizing Communications of Menswear on Retail Websites (온라인 쇼핑 사이트의 성인 남성복 제품 사이즈 정보 실태 분석)

  • Jaehyun Park;Ah Lam Lee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.47 no.1
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    • pp.73-84
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    • 2023
  • This study aims to identify the current sizing communication issues of menswear on retail websites and to suggest an effective size information presentation method. Based on sales frequency and awareness in the Korean menswear market, 22 brand websites were selected, and size-related information was investigated using 7 types of representative apparel items. The current diverse types of size codes had limitations in delivering actual product size information. Many websites preferred to display garment dimensions rather than basic body measurements, which is the suggested size designation method in Korean Standard. The websites posted fit model photos and customer reviews. However, the body size specifications, which consumers can use as a useful reference, were often omitted. There was also a high uncertainty in product size selection, with only the basic body measurement information listed, and there was a high deviation of garment dimensions within the same basic body measurements. The product size distribution did not match actual Korean body types. Based on the findings, we suggested improved effective sizing communication methods. These methods will contribute to a better online shopping environment for both consumers and retail sellers.

Frequency dependent squeezing for gravitational wave detectors using filter cavity and international collaboration of a filter cavity project for KAGRA (중력파 검출기의 양자 잡음 저감을 위한 필터 공동기 기반 주파수 의존 양자조임 기술과 KAGRA의 필터 공동기 제작을 위한 국제협력연구)

  • Park, June Gyu;Lee, Sungho;Kim, Chang-Hee;Kim, Yunjong;Jeong, Ueejeong;Je, Soonkyu;Seong, Hyeon Cheol;Han, Jeong-Yeol
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.37.3-38
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    • 2021
  • Radiation pressure noise of photon and photon shot noise are quantum noise limitation in interferometric gravita-tional wave detectors. Since relationship between the two noises is position and momentum of the Heisenberg uncertainty principle, quantum non-demolition (QND) technique is required to reduce the two noises at the same time. Frequency dependent squeezing using a filter cavity is one of realistic solutions for QND measurement and experimental results show that its cutting-edge performance is sufficient to apply to the current gravitational wave detectors. A 300m filter cavity is under construction at adv-LIGO. KAGRA (gravitational wave detector in Japan) has also started international collaboration to build a filter cavity. Recently we joined the filter cavity project for KAGRA. Current status of squeezing and filter cavity research at KASI and details of the KAGRA filter cavity project will be presented.

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Reverberation Mapping of Nearby AGN with Medium-band and LSGT

  • Kim, Joonho;Im, Myungshin;Choi, Changsu;Hwang, Sungyong
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.34.2-34.2
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    • 2020
  • Reverberation mapping is one of the best ways to investigate the physical mechanism of broad-line regions around central supermassive black holes of active galactic nuclei (AGNs). It is usually used to estimate the masses of supermassive black holes. Although spectroscopic reverberation mapping has used to study dozens of AGN, spectroscopic monitoring campaign of large sample is expansive. Here, we present results of photometric reverberation mapping with medium-band photometry. We monitored five nearby AGN which were already studied with H-alpha emission line. Observation has been performed for ~3 months with ~3 days cadence using three medium-band filters installed in LSGT (Lee Sang Gak Telescope; 0.43m). We found 0.01-0.08 magnitude variations from differential photometry. Also time-lags between continuum light-curves and H-alpha emission line light-curves are found using JAVELIN software. The result shows that our study and previous studies are consistent within uncertainty range. In the near future, medium-band photometric reverberation mapping seems useful to study large AGN samples. We will present preliminary result of following study that report new time lag measurement of six AGNs in the similar way.

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