산업단지 지하수 오염원 위치 및 누출 이력 규명 기술의 특성 분석

박유철 대한지질학회 2019 지질학회지 Vol.55 No.6

To investigate the problem of groundwater contamination caused by multiple contaminant sources in industrial complexes, we developed an identification method for contaminant source location and determination of release history, and analyzed the results of sensitivity analysis on the constraints of actual contaminant sites. The study site was the Woosan Industrial Complex, located in Wonju City, Gangwon Province. Numerical models were constructed based on field measurement data and multiple contaminant sources were identified. The simulation-optimization method was used for identification of contaminant sources and the genetic algorithm was used as the optimization method. For multiple contaminant sources, the larger the difference in the initial contaminant concentration of the contaminant source, the lower the average error rate of the contaminant source identification. For the sensitivity analysis of the contaminant source identification method, bias was imposed on the temporal or spatial characteristics of the contaminant concentration data. The average error rate increased with decrease in the number of contaminant concentration data, increase in the detection limit, or increase in the measurement error. The temporal or spatial bias of contaminant concentration data did not significantly affect the contaminant source identification ability on the average error rate. 산업단지에서 발생하는 다중오염원에 의한 지하수 오염 문제에 대하여 오염원 위치 및 누출이력에 대한 규명 기술을 개발하고, 실제 오염 현장의 제약 조건에 대한 민감도 분석을 수행한 결과를 분석하였다. 연구지역은강원도 우산공단이며, 현장 측정 자료를 바탕으로 수치모델을 구성하고, 다중 오염원 규명을 수행하였다. 오염원 규명 기술은 시뮬레이션-최적화 기법을 사용하였으며, 최적화 방법으로 유전알고리즘을 사용하였다. 다중오염원의 경우에 오염원의 초기 오염물질의 농도 차이가 클수록 오염원 규명의 평균 오차율이 감소하였다. 오염원 규명 기술의 민감도 분석을 위하여, 오염물질의 농도 자료에 대한 시간적 혹은 공간적 특성에 제한을 가하였다. 오염물질의 농도 자료의 개수가 감소하거나, 측정 한계가 증가하거나, 측정 오차가 증가하는 경우에 평균오차율이 증가하였다. 오염물질의 농도 자료의 시간적 혹은 공간적 편중 현상은 평균 오차율에 오염원 규명 능력에 큰 영향을 주지 않았다.

Direct tracking of noncircular sources for multiple arrays via improved unscented particle filter method

Yang Qian,Xinlei Shi,Haowei Zeng,Mushtaq Ahmad 한국전자통신연구원 2023 ETRI Journal Vol.45 No.3

Direct tracking problem of moving noncircular sources for multiple arrays is investigated in this study. Here, we propose an improved unscented particle filter (I-UPF) direct tracking method, which combines system proportional symmetry unscented particle filter and Markov Chain Monte Carlo (MCMC) algorithm. Noncircular sources can extend the dimension of sources matrix, and the direct tracking accuracy is improved. This method uses multiple arrays to receive sources. Firstly, set up a direct tracking model through consecutive time and Doppler information. Subsequently, based on the improved unscented particle filter algorithm, the proposed tracking model is to improve the direct tracking accuracy and reduce computational complexity. Simulation results show that the proposed improved unscented particle filter algorithm for noncircular sources has enhanced tracking accuracy than Markov Chain Monte Carlo unscented particle filter algorithm, Markov Chain Monte Carlo extended Kalman particle filter, and two-step tracking method.

Optimal Design of Irrigation Pipe Network with Multiple Sources

Lyu, Heui-Jeong,Ahn, Tae-Jin The Korean Society of Agricultural Engineers 1997 韓國農工學會誌 : 전원과 자원 Vol.39 No.2

Abstract This paper presents a heuristic method for optimal design of water distribution system with multiple sources and potential links. In multiple source pipe network, supply rate at each source node affects the total cost of the system because supply rates are not uniquely determined. The Linear Minimum Cost Flow (LMCF) model may be used to a large scale pipe network with multiple sources to determine supply rate at each source node. In this study the heuristic method based on the LMCF is suggested to determine supply rate at each source node and then to optimize the given layout. The heuristic method in turn perturbs links in the longest path of the network to obtain the supply rates which make the optimal design of the pipe network. Once the best tree network is obtained, the frequency count of reconnecting links by considering link failure is in turn applied to form loop to enhance the reliability of the best tree network. A sample pipe network is employed to test the proposed method. The results show that the proposed method can yield a lower cost design than the LMCF alone and that the proposed method can be efficiently used to design irrigation systems or rural water distribution systems.

A practical subcritical rod worth measurement technique based on the improved neutron source multiplication method

Jiahe Bai,Chenghui Wan,Ser Gi Hong,Hongchun Wu Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.4

The control rod worth is a key safety parameter required to be measured in commercial pressurized water reactors (PWRs). Conventionally, the control rod worth is measured after reaching the critical state, which occupies the considerable time in the zero-power physics test. In this study, an efficient control-rod worth measurement technique has been proposed based on the improved neutron-source multiplication method, which can be implemented with the source-range detector count rates in the subcritical states. Moreover, the noise reduction technique has been adopted to smooth the large fluctuation existing in the original signals. In order to verify the engineering performance of the proposed measurement technique, the measured source-range detector count rates during the rod withdrawal process before reaching critical state in a CNP1000 reactor have been employed. It demonstrated that almost all estimated results of control rod worth satisfy the engineering acceptance criteria, except one control rod with the relative difference over 10 %, which indicates the capability of the proposed method in estimating control rod worth.

KURT 환경 자료를 이용한 가상의 다중 발생원에서의 누출 핵종의 이동시간 평가

고낙열,정종태,김경수,황영택 한국방사성폐기물학회 2013 방사성폐기물학회지 Vol.11 No.4

KURT(KAERI Underground Research Tunnel) 부지 부근에 가상의 처분장을 설정하고, 해당 부지의 세 지점에서 방사성폐기물로부터 누출된다고 가정한 방사성 핵종의 이동 시간을 계산하였다. 핵종의 이동 경로는 핵종 누출 지점에서 천부 지하수대까지로 설정하고 KURT 주변 지하수 유동계 모의를 통해 결정하였다. 세 지점은 지하수가 빠르게 유동하는 구조(highlywater-conductive feature)를 지나가기 때문에 천부 지하수까지 도달하는데 상대적으로 적은 시간이 걸리는 지점으로 선정되었다. 핵종의 이동 시간은 TDRW(Time-Domain Random Walk) 기법을 통해 계산하였다. 지하수 내의 핵종의 이동 시간을 계산하기 위해, 이류(advection)와 분산(dispersion) 이외에 암반 기질(rock matrix)로의 확산(diffusion)과 기질 내부에서의 흡착(sorption)이 고려되었고, 핵종의 붕괴 및 변환에 의한 영향도 몇 개의 붕괴 사슬(decay chain)을 이용하여 계산에반영하였다. 계산 결과를 보면, 지표 부근의 천부 지하수에 도달하는 핵종의 시간당 이동량(mass flux)은 복수의 이동 경로뿐만 아니라 핵종의 반감기와 암반 기질 내에서의 핵종의 흡착 분배 계수에 크게 영향을 받는 것으로 나타났다. 따라서 보다 안정적이고 불확실성이 감소된 심지층 처분장의 안전성 평가를 위해 우선적으로 필요한 사항으로는, 장반감기 핵종에 대한 평가가 이동 과정 이외에 저장 용기에 들어있는 상태에서부터 면밀하게 이루어져야 하고, 암반 기질에서 발생하는 핵종의 흡착 과정이 심부 현장 조건을 반영하여 평가되어야 할 것으로 생각된다. A hypothetical repository was assumed to be located at the KURT (KAERI Underground Research Tunnel) site,and the travel times of radionuclides released from three source positions were calculated. The groundwater flowaround the KURT site was simulated and the groundwater pathways from the hypothetical source positions to theshallow groundwater were identified. Of the pathways, three pathways were selected because they had highly water-conductive features. The transport travel times of the radionuclides were calculated by a TDRW (Time-DomainRandom Walk) method. Diffusion and sorption mechanisms in a host rock matrix as well as advection-dispersionmechanisms under the KURT field condition were considered. To reflect the radioactive decay, four decay chainswith the radionuclides included in the high-level radioactive wastes were selected. From the simulation results, thehalf-life and distribution coefficient in the rock matrix, as well as multiple pathways, had an influence on the massflux of the radionuclides. For enhancing the reliability of safety assessment, this reveals that identifying the historyof the radionuclides contained in the high-level wastes and investigating the sorption processes between the radionuclidesand the rock matrix in the field condition are preferentially necessary.

음원 방향각 추정에 관한 계산기 시뮬레이션

이채봉,김정국,김길중 東西大學校 1998 동서논문집 Vol.4 No.-

In this paper describes the optimum beamforming algorithm when it estimates source signal localization. It is proposed many methods for the identification of a sound source localization. But in this study, compares and ivestigates the angle resolution and sharp peak value by the simulation. The simulation perform to each of DSA(Delay Sum Arry), MV(Minimum Variance), MUSIC(MUltiple SIgnal Classification) method when signals with two or three frequency exist. In result, the MUSIC method has excellent angle resolution and sharp peak value in estimating the derection of arrival signals at each microphone for arbitrary direction of the sound source singnal.

Modeling of multiple sources of workload and time pressure effect with ACT-R

Park, Sungjin,Jeong, Sungoo,Myung, Rohae Elsevier 2018 International journal of industrial ergonomics Vol.63 No.-

<P><B>Abstract</B></P> <P>Workload is the most critical element to be evaluated in the design of a new system or interface because it generally tends to be closely connected with an operator's overall performance. However, few existing simulation models are able to cover the major sources of workload or simulate the time pressure effect on information processing and workload. In this study, a mathematical model to quantitatively compute the multiple sources of workload with a cognitive architecture, Adaptive Control of Thought – Rationale (ACT-R), is proposed, which at the same time reflects the effect of time pressure. Specifically, mathematical equations were developed to quantify each subscale of the National Aeronautics and Space Administration Task Load Index (NASA-TLX) and the time pressure effect on information processing speed. The proposed method not only successfully estimates each subscale of NASA-TLX but also simulates the change of human performance and workload by time pressure, comparing the simulated values by the proposed method to performance time by the experiment and subjective ratings of NASA-TLX, as measured by participants on an experiment in the Kanfer-Ackerman Air Traffic Control (KA-ATC) task. There is also a discussion about further usage and implementation of this method in designing a complex system or interface. Practicably speaking, in domains of complex system or interface design, the proposed method can be used to quantitatively estimate the operator's workload and comprehend where the operator workload is concentrated early on, in the design phase.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simulation model was developed to model multiple sources of mental workload. </LI> <LI> Several mathematical equations were developed to estimate subscales of NASA-TLX. </LI> <LI> The proposed model can also reflect the time pressure effect. </LI> <LI> The simulation results were highly matched with experimental results by subjects. </LI> <LI> The model can be used to evaluate the interface early on in the design phase. </LI> </UL> </P>

Comparison of Validity of Food Group Intake by Food Frequency Questionnaire Between Pre- and Post-adjustment Estimates Derived from 2-day 24-hour Recalls in Combination with the Probability of Consumption

Kim, Dong-Woo,Oh, Se-Young,Kwon, Sung-Ok,Kim, Jeong-Seon Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

Validation of a food frequency questionnaire (FFQ) utilising a short-term measurement method is challenging when the reference method does not accurately reflect the usual food intake. In addition, food group intake that is not consumed on daily basis is more critical when episodically consumed foods are related and compared. To overcome these challenges, several statistical approaches have been developed to determine usual food intake distributions. The Multiple Source Method (MSM) can calculate the usual food intake by combining the frequency questions of an FFQ with the short-term food intake amount data. In this study, we applied the MSM to estimate the usual food group intake and evaluate the validity of an FFQ with a group of 333 Korean children (aged 3-6 y) who completed two 24-hour recalls (24HR) and one FFQ in 2010. After adjusting the data using the MSM procedure, the true rate of non-consumption for all food groups was less than 1% except for the beans group. The median Spearman correlation coefficients against FFQ of the mean of 2-d 24HRs data and the MSM-adjusted data were 0.20 (range: 0.11 to 0.40) and 0.35 (range: 0.14 to 0.60), respectively. The weighted kappa values against FFQ ranged from 0.08 to 0.25 for the mean of 2-d 24HRs data and from 0.10 to 0.41 for the MSM-adjusted data. For most food groups, the MSM-adjusted data showed relatively stronger correlations against FFQ than raw 2-d 24HRs data, from 0.03 (beverages) to 0.34 (mushrooms). The results of this study indicated that the application of the MSM, which was a better estimate of the usual intake, could be worth considering in FFQ validation studies among Korean children.

The first application of modified neutron source multiplication method in subcriticality monitoring based on Monte Carlo

Wang, Wencong,Liu, Caixue,Huang, Liyuan Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.3

The control rod drive mechanism needs to be debugged after reactor fresh fuel loading. It is of great importance to monitor the subcriticality of this process accurately. A modified method was applied to the subcriticality monitoring process, in which only a single control rod cluster was fully withdrawn from the core. In order to correct the error in the results obtained by Neutron Source Multiplication Method, which is based on one point reactor model, Monte Carlo neutron transport code was employed to calculate the fission neutron distribution, the iterated fission probability and the neutron flux in the neutron detector. This article analyzed the effect of a coarse mesh and a fine mesh to tally fission neutron distributions, the iterated fission probability distributions and to calculate correction factors. The subcriticality before and after modification is compared with the subcriticality calculated by MCNP code. The modified results turn out to be closer to calculation. It's feasible to implement the modified NSM method in large local reactivity addition process using Monte Carlo code based on 3D model.

다파장 간섭계에서의 파장선택방법

김윤석(Y. Kim),진종한(J. Jin),김영진(Y.-J. Kim),현상원(S. Hyun),김승우(S.-W. Kim) 한국정밀공학회 2007 한국정밀공학회 학술발표대회 논문집 Vol.2007 No.11월