• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.702-708
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• 2019

This paper deals with break size estimation of loss of coolant accidents (LOCA) using a nonlinear autoregressive with exogenous inputs (NARX) neural network. Previous studies used static approaches, requiring time-integrated parameters and independent firing algorithms. NARX neural network is able to directly deal with time-dependent signals for dynamic estimation of break sizes in real-time. The case studied is a LOCA in the primary system of Bushehr nuclear power plant (NPP). In this study, number of hidden layers, neurons, feedbacks, inputs, and training duration of transients are selected by performing parametric studies to determine the network architecture with minimum error. The developed NARX neural network is trained by error back propagation algorithm with different break sizes, covering 5% -100% of main coolant pipeline area. This database of LOCA scenarios is developed using RELAP5 thermal-hydraulic code. The results are satisfactory and indicate feasibility of implementing NARX neural network for break size estimation in NPPs. It is able to find a general solution for break size estimation problem in real-time, using a limited number of training data sets. This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr NPP.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.607-615
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• 2022

In this study, economic analysis program was developed for economic evaluation of hydrogen production, storage/delivery, and utilization technologies as well as overseas import of hydrogen. Economic analysis program can be used for the estimation of the levelized cost of hydrogen for hydrogen supply chain technologies. This program include five hydrogen production technology on steam methane reforming and water electrolysis, two hydrogen storage technologies (high compressed gas and liquid hydrogen storage), three hydrogen delivery technologies (compressed gas delivery using tube trailer, liquid hydrogen, and pipeline transportation) and six hydrogen utilization technologies on hydrogen refueling station and stationary fuel cell system. In the case of overseas import hydrogen, it was considered to be imported from five countries (Austraila, Chile, India, Morocco, and UAE), and the transportation methods was based on liquid hydrogen, ammonia, and liquid organic hydrogen carrier. Economic analysis program that was developed in this study can be expected to utilize for planning a detailed implementation methods and hydrogen supply strategies for the hydrogen economy road map of government.

• Journal of Korea Water Resources Association
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• v.51 no.4
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• pp.301-311
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• 2018

Recently, the flood inundation caused by heavy rainfall in urban area is increasing due to global warming. The variability of climate change is described in the IPCC 5th report (2014). The precipitation pattern and hydrological system is varied by climate change. Since the heavy rainfall surpassed the design capacity of the pipeline, it caused great damage in metropolitan cities such as Seoul and Busan. Inundation in urban area is primarily caused by insufficient sewer capacity and surplus overflow of river. Inundation in urban area with concentrated population is more dangerous than rural and mountains areas, because it is accompanied by human casualties as well as socio-economic damage to recover destruction of roads, brides and underground spaces. In addition, various factors such as an increase in impervious area, a short time of concentration to outlet, and a shortage of sewer capacity's lack increase flooding damage. In this study, flood inundation analysis was conducted for vulnerable areas using XP-SWMM. Also, three structural flood prevention measures such as drainage pipeline construction, detention reservoir construction, and flood pumping station construction are applied as flood damage prevention alternatives. The flood data for each alternative were extracted by dividing the basin by grid. The Spatial Compromise Programming are applied using flood assessment criteria, such as maximum inundation depth, inundation time, and construction cost. The purpose of this study is to reflect the preference of alternatives according to geographical condition even in the same watershed and to select flood defense alternative considering regional characteristics.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.5 s.311
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• pp.44-59
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• 2006

This paper describes the efficient implementation of DNA sequence generate system with genetic algorithm for reducing computation time of NACST. The proposed processor is based on genetic algerian with fitness functions which would suit the point of reference for generated sequences. In order to implement efficient hardware structure, we used the pipelined structure. In addition our design was applied the parallelism to achieve even better simulation time than the sequence generator system which is designed on software. In this paper, our hardware is implemented on the FPGA board with xc2v6000 devices. Through experiment, the proposed hardware achieves 467 times speed-up over software on a PC and sequence generate performance of hardware is same with software.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.469-472
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• 2003

A life cycle cost analysis model for public water supply systems should be different from the ones for other civil and architectural facilities as the operation and the maintenance cost of the water supply systems mainly come from the various mechanical systems and the pipeline systems of the collecting/treating/distributing facilities. This paper presents a cost classification scheme and a life cycle cost analysis model for public water supply systems. A value analysis (VA) procedure that is well suited for practical purposes is also presented. The presented life cycle model and the value analysis procedure were applied to a real world project, and this case study is discussed in the paper. The model and the procedure presented in this study can greatly contribute to the value-oriented design alternative selection, the estimation of the maintenance cost, and the allocation of budget for water supply system construction projects.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.185-190
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• 2005

This study is to determine an optimal reservoir among many alternative proposals in order to obtain the maximized efficiency under the limited budget. There are many alternative proposals which deal with problems to assign reservoir such as water conversion establishment construction, subterranean water, reservoir, submarine pipeline, water bort, and marine water saving base construction. In this paper, the new model to assign the most reasonable alternative is introduced using 0-1 integer programming. This proposed model has not been applied in the optimal reservoir selection problem yet. This paper will contribute to determine the most reasonable alternative to minimize budget under constraints. Also, this proposal model can be applied to other reservoir selection problem in other regions.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.11-19
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• 2006

Sewerage is the system that improves the quality of human life and prevents many disasters such as floods. However the investigators in Korea only have been concerned about the sewer system, so the sewage treatment plant stays in the basic level like mapping. For example, only one attribute can be recognized in the linear object. Because of this limitation, it makes difficult to manage the linear attribute regarding to the sewage pipe plan. And it is impossible to control a partial (point type, line type) attribute changes of the linear object. We will therefore present the applicable method for the attribute changes of the linear object like the sewage pipe plans. For this reason, this paper is designed on the basis of Dynamic Segmentation(DS). DS has the advantage of giving the attribute value to the exact place in the linear object. As a result of using DS, the variety environment changes around the sewage pipes are applied to the building sewerage data. This also makes it possible to get a precise estimation for the maximum dirty water amount.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.25-32
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• 2019

In many mass-consumption gas facilities, natural gas is not supplied through the pipeline of the gas corporation. LNG is supplied from the gas corporation through the tank lorry to be vaporized. In order to prevent human or property damage due to gas leakage at these facilities, a study was conducted to analyze the concentration of odorant injected at the initial and consumption points. An analysis was performed to confirm the change in odorant concentration according to the pipe position in the gas facility when a constant flow rate flowed. For this study the gas samples were taken with aluminium cylinders(4.5 L) which were created a vacuum at the pressure regulator in which the odorants was injected and the points using the gas. Odorant levels of the samples were analyzed by Gas chromatography(Main Body : Agilent 7890A, Detector : ANTEC 7090).We suggest that the small facilities using LNG need to make the management system by the types of facilities for maintaining the odorization system.

• Journal of IKEEE
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• v.24 no.3
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• pp.783-790
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• 2020

In this paper, the human detecting radar system for indoor security applications is proposed, and its FPGA-based implementation results are presented. In order to minimize the complexity and memory requirements of the computation, the top half of the spectrogram was used to extract features, excluding the feature extraction techniques that require complex computation, feature extraction techniques were proposed considering classification performance and complexity. In addition, memory requirements were minimized by designing a pipeline structure without storing the entire spectrogram. Experiments on human, dog and robot cleaners were conducted for classification, and 96.2% accuracy performance was confirmed. The proposed system was implemented using Verilog-HDL, and we confirmed that a low-area design using 1140 logics and 6.5 Kb of memory was possible.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.54.3-55
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• 2016

DEEP-South Scheduling and Data reduction System (DS SDS) consists of two separate software subsystems: Headquarters (HQ) at Korea Astronomy and Space Science Institute (KASI), and SDS Data Reduction (DR) at Korea Institute of Science and Technology Information (KISTI). HQ runs the DS Scheduling System (DSS), DS database (DB), and Control and Monitoring (C&M) designed to monitor and manage overall SDS actions. DR hosts the Moving Object Detection Program (MODP), Asteroid Spin Analysis Package (ASAP) and Data Reduction Control & Monitor (DRCM). MODP and ASAP conduct data analysis while DRCM checks if they are working properly. The functions of SDS is three-fold: (1) DSS plans schedules for three KMTNet stations, (2) DR performs data analysis, and (3) C&M checks whether DSS and DR function properly. DSS prepares a list of targets, aids users in deciding observation priority, calculates exposure time, schedules nightly runs, and archives data using Database Management System (DBMS). MODP is designed to discover moving objects on CCD images, while ASAP performs photometry and reconstructs their lightcurves. Based on ASAP lightcurve analysis and/or MODP astrometry, DSS schedules follow-up runs to be conducted with a part of, or three KMTNet telescopes.