• Nuclear Engineering and Technology
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• 제54권3호
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• pp.1109-1114
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• 2022

The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the feasibility and applicability of a 3D-based equivalent model using dynamic condensation method for seismic analysis of a SMART control rod drive mechanism. The equivalent model is utilized for complicated seismic analysis during the design of the SMART. While the 1D-based beam-mass equivalent model is widely used in the nuclear industry for its calculation efficiency, the 3D-based equivalent model is suggested for the seismic analysis of SMART to enhance the analysis accuracy of the 1D-based equivalent model while maintaining its analysis efficiency. To verify the suggested model, acceleration response spectra from seismic analysis based on the 3D-based equivalent model are compared to those from the 1D-based beam-mass equivalent model and experiments. The accuracy and efficiency of the dynamic condensation method are investigated by comparison to analysis results based on the conventional modeling methodology used for seismic analysis.

• Advances in Computational Design
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• 제7권4호
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• pp.345-369
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• 2022

Infectious disease emergency hospitals are usually temporarily built during the pneumonia epidemic with higher requirements regarding diagnosis and treatment efficiency, hygiene and safety, and infection control.This study aims to identify how the Building Information Modeling (BIM) + Industrialized Building System (IBS) approach could rapidly deliver an infectious disease hospital and develop site epidemic spreading algorithms. Coronavirus-19 pneumonia construction site spreading algorithm model mind map and block diagram of the construction site epidemic spreading algorithm model were developed. BIM+IBS approach could maximize the repetition of reinforced components and reduce the number of particular components. Huoshenshan Hospital adopted IBS and BIM in the construction, which reduced the workload of on-site operations and avoided later rectification. BIM+IBS integrated information on building materials, building planning, building participants, and construction machinery, and realized construction visualization control and parametric design. The delivery of Huoshenshan Hospital was during the most critical period of the Coronavirus-19 pneumonia epidemic. The development of a construction site epidemic spreading algorithm provided theoretical and numerical support for prevention. The agent-based analysis on hospital evacuation observed "arched" congestion formed at the evacuation exit, indicating behavioral blindness caused by fear in emergencies.

• 한국농공학회논문집
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• 제65권5호
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• pp.81-91
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• 2023

As abnormal weather conditions escalate, water disasters such as droughts and floods occur more frequently. These natural disasters are fatal to agricultural reservoirs, where the operation techniques vary greatly depending on the season and weather conditions, and response through intake works is limited. In response, governments like the Korea Rural Community Corporation have researched efficient water supply methods through irrigation channels. Therefore, previous studies analyzed the irrigation process using numerical models to determine an efficient irrigation system. However, SWMM and EPANET used in previous studies are limited in quantitative agricultural irrigation process analysis. Therefore, this study developed AIRISS to simulate and analyze agricultural irrigation. Specifically, we simulated the irrigation process in the Ssangbong area of South Korea and simulated the irrigation process to verify the performance of the numerical model. AIRISS, developed in this study, is specialized in simulating the agricultural irrigation process. It can check the supply to each paddy and the condition of each paddy.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.465-477
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• 2023

In proton exchange membrane fuel cell (PEMFC), proper thermal management of the stack and moisture generation by electrochemical reactions significantly affect fuel cell performance. In this study, the PEMFC dynamic characteristic model was developed through Simcenter AMESim, a development program. In addition, the developed model aims to understand the thermal resin balance of the stack and performance characteristics for input loads. The developed model applies the thermal management model of the stack and the moisture content and permeability model to simulate voltage loss and stack thermal behavior precisely. This study extended the C based AMESet (adaptive modeling environment submodeling tool) to simulate electrochemical reactions inside the stack. Fuel cell model of AMESet was liberalized with AMESim and then integrated with the balance of plant (BOP) model and analyzed. And It is intended to be used in component design through BOP analysis. The resistance loss of the stack and thermal behavior characteristics were predicted, and the impact of stack performance and efficiency was evaluated.

• 산업경영시스템학회지
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• 제46권4호
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• pp.281-293
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• 2023

This study addresses the optimal design methodology for switching between active electronically scanned array (AESA) radar operating modes to easily select the necessary information to reduce pilots' cognitive load and physical workload in situations where diverse and complex information is continuously provided. This study presents a procedure for defining a hidden Markov chain model (HMM) for modeling operating mode changes based on time series data on the operating modes of the AESA radar used by pilots while performing mission scenarios with inherent uncertainty. Furthermore, based on a transition probability matrix (TPM) of the HMM, this study presents a mathematical programming model for proposing the optimal structural design of AESA radar operating modes considering the manipulation method of a hands on throttle-and-stick (HOTAS). Fighter pilots select and activate the menu key for an AESA radar operation mode by manipulating the HOTAS's rotary and toggle controllers. Therefore, this study presents an optimization problem to propose the optimal structural design of the menu keys so that the pilot can easily change the menu keys to suit the operational environment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.241-241
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• 2012

Semiconductor industry has been taking the advantage of improvements in process technology in order to maintain reduced device geometries and stringent performance specifications. This results in semiconductor manufacturing processes became hundreds in sequence, it is continuously expected to be increased. This may in turn reduce the yield. With a large amount of investment at stake, this motivates tighter process control and fault diagnosis. The continuous improvement in semiconductor industry demands advancements in process control and monitoring to the same degree. Any fault in the process must be detected and classified with a high degree of precision, and it is desired to be diagnosed if possible. The detected abnormality in the system is then classified to locate the source of the variation. The performance of a fault detection system is directly reflected in the yield. Therefore a highly capable fault detection system is always desirable. In this research, time series modeling of the data from an etch equipment has been investigated for the ultimate purpose of fault diagnosis. The tool data consisted of number of different parameters each being recorded at fixed time points. As the data had been collected for a number of runs, it was not synchronized due to variable delays and offsets in data acquisition system and networks. The data was then synchronized using a variant of Dynamic Time Warping (DTW) algorithm. The AutoRegressive Integrated Moving Average (ARIMA) model was then applied on the synchronized data. The ARIMA model combines both the Autoregressive model and the Moving Average model to relate the present value of the time series to its past values. As the new values of parameters are received from the equipment, the model uses them and the previous ones to provide predictions of one step ahead for each parameter. The statistical comparison of these predictions with the actual values, gives us the each parameter's probability of fault, at each time point and (once a run gets finished) for each run. This work will be extended by applying a suitable probability generating function and combining the probabilities of different parameters using Dempster-Shafer Theory (DST). DST provides a way to combine evidence that is available from different sources and gives a joint degree of belief in a hypothesis. This will give us a combined belief of fault in the process with a high precision.

• 대한원격탐사학회지
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• 제24권2호
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• pp.99-106
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• 2008

영상 레이다(SAR)는 주야간, 일조량에 관계없이 전천후로 영상획득이 가능하여 군사용으로는 물론 과학 민수용으로 광범위하게 활용된다. SAR 시스템에서는 고도, 운용 주파수, PRF 등의 다양한 시스템설계 파라미터로부터 생성된 임펄스 응답 함수(impulse response function)를 분석하여 공간해상도, PSLR, ISLR 등 영상품질 성능 파라미터의 추정이 가능하다. 그러나 모델링된 임펄스 응답 특성은 주변 클러터 환경이 고러되지 않은 이상적인 경우이므로 실제 주변 클러터 환경을 고려한 SAR 영상품질 분석 기법이 필요하다. 본 논문에서는 먼저 주요 SAR시스템 파라미터를 기반으로 SAR 점표적 원시 데이터를 생성하고, 거리-도플러 알고리듬(range-Doppler algorithm)을 이용하여 임펄스 응답 데이터를 형성한다. 그리고 실제 SAR영상의 일부분을 추출하여 주변 배경 클러터 환경 데이터를 형성한 후, 임펄스 응답 데이터를 삽입한다. 형성된 응답 데이터는 영상품질의 정확도를 향상시키고자 확장보간법을 도입하여 분석하고, 이에 대한 효과를 주요 도플러 파라미터인 방위 FM율 오차에 따른 성능분석을 수행함으로써 확인한다.

• 한국인터넷방송통신학회논문지
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• 제19권3호
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• pp.73-82
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• 2019

스마트팩토리를 구축하기 위해서는 CPPS(Cyber Physical Production System)의 구축은 필수적으로 동반되어야 하는 중요한 시스템이다. CPPS를 통해서 물리적 공장을 디지털 기반의 사이버 세상으로 옮겨오고 이를 지능적, 자율적으로 모니터링하고 제어하는 것이 스마트팩토리의 실체이다. 하지만 기존에 제시된 CPPS의 아키텍처들은 추상적인 모델링 형태의 아키텍처만 제시하고 있으며, 스마트팩토리에서 데이터를 수 집 교환을 위한 국제 표준인 OPC UA Framework(Open Platform Communication Unified Architecture)을 CPPS의 기본적인 체계로 적용한 연구는 부족하였다. 이에 아키텍처 구성 실제 공장에 적용 가능한 CPPS 아키텍처로 분산되어진 필드 데이터를 수집하여 중앙에 집중화 된 서버에서 집중된 데이터 처리가 되어야만 클라우드와 IoT를 모두 포함할 수 있는 CPPS를 구현 가능하다. 본 연구에서는 중앙 처리 OPC UA Framework을 준수한 OPC UA를 기술 체계를 기반으로 중앙의 OPC UA Server를 통해 CPPS 아키텍처를 구현하고 OPC UA 모델링 처리를 통해 CPPS 논리 프로세스와 데이터 처리 프로세스가 자동으로 생성되는 방법을 포함한 CPPS 아키텍처를 제안하고 모델 공장을 실제로 구현하여 그 성능과 가용성에 대해서 연구하였다.

• 대한토목학회논문집
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• 제29권1D호
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• pp.1-9
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• 2009

버스정보시스템(bus information system, BIS)은 지능형교통시스템(intelligent transportation systems, ITS)의 일환으로서 버스정류장에서 버스를 기다리고 있는 이용자들에게 실시간의 버스교통정보를 제공하는 첨단대중교통시스템의 하나이다. 그러나 본 연구대상지역인 울산광역시를 포함하여 버스정보시스템을 운영하고 있는 대부분의 도시에서는 아직 적정의 버스도착시간 예측모형이 구축되어 있지 않기 때문에 현재의 버스위치, 이용자들의 버스 기다리는 시간, 버스 도착시간 등의 보다 정확한 버스정보가 버스 이용자들에게 제공되지 않는 상황이다. 따라서 본 연구에서는 연구대상 간선도로에 대해 실시간의 버스교통특성 자료를 조사하여 버스운행특성을 확인하고, 연구대상구간을 버스 정류장, 교차로 및 순행구간의 단위구간으로 세분하여 각 단위구간에 대해 지수평활법, 가중평활법 및 Kalman Filter법을 적용하여 최적의 단위구간 통행시간 예측모형을 구축하며, 마지막으로 버스정류장에서 실시간의 버스도착시간을 예측하기 위한 최적의 통합모형을 제시하고자 한다.

• 마이크로전자및패키징학회지
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• 제23권2호
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• pp.85-89
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• 2016

본 논문에서는 형광 이미징 시스템의 대역통과필터의 회전에 의한 특성 변화를 관찰하였다. 이론적 모델을 통해 대역통과필터의 투과율 및 대역폭이 회전각에 따라 변한다는 것을 알 수 있고, 회전각에 따른 파장별 투과율 측정을 통해 이를 입증하였다. 그러므로 대역통과필터의 회전에 따른 특성변화를 이용하면 바이오 영상 장치를 정밀하게 조절하여 시스템의 형광 신호를 더욱 강하게 하고, 양질의 영상을 얻을 수 있다.