• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1757-1762
• /
• 2003

With distribution industrial control system, the use of low cost to achieve a highly reliable and safe system in real time distributed embedded application is proposed. This developed intelligent node is based on two microcontrollers, one for the execution of the application code, also as master controller for ensuring the real time control & the logic operation with PLD and other for communication task and the easy control execution, i.e., I/O digital input, digital output and interrupting. This paper also presents where the case NCS (Networked control system) with LonTalk protocol is applied for the filtration process control system of a small water treatment plant.

• Membrane and Water Treatment
• /
• v.3 no.3
• /
• pp.201-209
• /
• 2012

Membrane separation technologies have some of advantages are considered a better alternative to traditional methods. Research of novel membranes is very vital for covering the higher required of membrane in several purposes like water desalting technology. In this work polyamide-6/cellulose acetate (PA-6/CA) blend membrane was developed according to the wet phase inversion system. The structures of the prepared membranes were examined by scanning electron microscopy (SEM). SEM images showed uniform particles distribution in the prepared membranes. Moreover, SEM images revealed that the membranes have relatively uniform surface (PA-6/CA). PA-6/CA blend membranes systems are evaluated by using synthetic NaCl solution. The separation performance showed that salt rejection increased with increasing of heat treatment of the casted films and it was improved with increasing of operating pressure.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.3
• /
• pp.385-391
• /
• 2004

This paper examines the applicability of DAF-system to the domestic sewers for the effective CSOs treatment. The procedures for the experiment include mainly two steps. One is to analyse the water qualities and settling test of the CSOs and the other focuses on general characteristics of the CSOs such as the removal efficiency of pollutant, the distribution of particle size and mass balance of DAF-system. The result of this study show that the application of DAF-system is more effective and economical than the existing treatment systems because it has two removal mechanisms of sedimentation and flotation simultaneously.

• Proceedings of the Korea Water Resources Association Conference
• /
• 1993.07a
• /
• pp.535-543
• /
• 1993

이 논문의 목적은 기존의 상수도 관망을 개선하는데 있어 어느 관을 교체 또는 재생할 것인가와 펌프용량을 얼마나 늘릴 것인가를 결정함으로써 관망내 각 급수지점에서의 요구유량및 수압을 만족시킴은 물론 그에 드는 비용을 최소화시키는 모델을 개발하는데 있다. 이 논문은 관교체 비용, 세관 및 재생 비용, 관보수 비용, 펌핑 비용, 펌프시설 확충비용 등의 다섯가지 비용들을 비교 검토함으로써 의사결정을 하게 된다. 제약조건식으로는 급수 조건식, 에너지 방정식, 수리학적 방정식, 결정 조건식, 한계 조건식, 정수 조건식 등이 있다. 이 모델을 수식화하면 정수혼합 비선형계획법 (mixed-integer nonlinear programming, MINLP) 문제가 된다. 이 문제를 풀기 위해 비선형해법의 GRG (generalized reduced gradient) 방법과 분기와 한계 (banch and bound) 기법을 통한 implicit enumeration 기법을 접목시키는 방법을 제안하였다.

• Nuclear Engineering and Technology
• /
• v.48 no.4
• /
• pp.975-981
• /
• 2016

The containment response during the first 24 hours of a low-pressure severe accident scenario in a nuclear power plant with a two-loop Westinghouse-type pressurized water reactor was simulated with the CONTAIN 2.0 computer code. The accident considered in this study is a large-break loss-of-coolant accident, which is not successfully mitigated by the action of safety systems. The analysis includes pressure and temperature responses, as well as investigation into the influence of spray on the retention of fission products and the prevention of hydrogen combustion in the containment.

• Fire Science and Engineering
• /
• v.19 no.4 s.60
• /
• pp.32-36
• /
• 2005

A water mist system was considered as a possible alternative to a gaseous suppression system that can not prevent re-ignition after fire extinguishment for a power transformer room. This study deals with the fire suppression capability of the water mist systems. High-and low-pressure water mist systems were examined to compare efficiency of both systems. The power transformer examined in this study occupied about $7\%$ of a $10m\times10m\times$ transformer room. Full-scale suppression tests were performed for six different fire scenarios: two spray fires, three pool fires and one cascade fire. The fire suppression test results demonstrated that the high-pressure system was superior to the low-pressure system, especially considering oxygen depletion and the ambient temperature distribution.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.6
• /
• pp.133-141
• /
• 2009

The main objective of water distribution system is to supply enough water to users with proper pressure. Hydraulic analysis of water distribution system can be divided into Demand Driven Analysis (DDA) and Pressure Driven Analysis (PDA). Demand-driven analysis can give unrealistic results such as negative pressures in nodes due to the assumption that nodal demands are always satisfied. Pressure-driven analysis which is often used as an alternative requires a Head-Outflow Relationship (HOR) to estimate the amount of possible water supply at a certain level of pressure. However, the lack of data causes difficulty to develop the relationship. In this study, effective supply, which is the possible amount of supply while meeting the pressure requirement in nodes, is proposed to estimate the serviceability and user's convenience of the network. The effective supply is used to calculate Subsystem Importance Index (SII) which indicates the effect of isolating a subsystem on the entire network. Harmony Search, a stochastic search algorithm, is linked with EPANET to maximize the effective supply. The proposed approach is applied in example networks to evaluate the capability of the network when a subsystem is isolated, which can also be utilized to prioritize the rehabilitation order or evaluate reliability of the network.

• Journal of Korean Society on Water Environment
• /
• v.26 no.6
• /
• pp.943-947
• /
• 2010

Runoff ratio of paddy fields for the application of Event Mean Concentration (EMC) method was studied. To measure actual runoff ratio of paddy fields, a field monitoring was conducted for 2008 ~ 2009 period. Long-term rainfall data of four cities in major river basins were analyzed and weighting factors were developed to consider temporal and spatial variation of rainfall distribution of Korean peninsula. The observed runoff ratio ranged 0.00 ~ 1.20 and arithmetic mean were 0.25, respectively. However, the representative runoff ratio for paddy fields was determined as 0.41 according to the method suggested by National Institute of Environmental Research (NIER).

• Journal of Astronomy and Space Sciences
• /
• v.40 no.4
• /
• pp.149-171
• /
• 2023

ShadowCam is a National Aeronautics and Space Administration Advanced Exploration Systems funded instrument hosted onboard the Korea Aerospace Research Institute (KARI) Korea Pathfinder Lunar Orbiter (KPLO) satellite. By collecting high-resolution images of permanently shadowed regions (PSRs), ShadowCam will provide critical information about the distribution and accessibility of water ice and other volatiles at spatial scales (1.7 m/pixel) required to mitigate risks and maximize the results of future exploration activities. The PSRs never see direct sunlight and are illuminated only by light reflected from nearby topographic highs. Since secondary illumination is very dim, ShadowCam was designed to be over 200 times more sensitive than previous imagers like the Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC). ShadowCam images thus allow for unprecedented views into the shadows, but saturate while imaging sunlit terrain.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.2
• /
• pp.53-63
• /
• 2016

Monitoring of cyanobacteria bloom in reservoir systems is important for water managers responsible of water supply system. Cyanobacteria affect the taste and smell of water and pose considerable filtration problems at water use places. Harmful cyanobacteria bloom in reservoir have significant economic impacts. We develop a new method for estimating the cyanobacteria bloom using Landsat TM and ETM+ data. Developed model was calibrated and cross-validated with existing in situ measurements from Daecheong Reservoir's Water Quality Monitoring Program and Algae Alarm System. Measurements data of three stations taken from 2004 to 2012 were matched with radiometrically converted reflectance data from the Landsat TM and ETM+ sensor. Stepwise multiple linear regression was used to select wavelengths in the Landsat TM and ETM+ bands 1, 2 and 4 that were most significant for predicting cyanobacteria cell number and bio-volume. Based on statistical analysis, the linear models were that included visible band ratios slightly outperformed single band models. The final monitoring models captured the extents of cyanobacteria blooms throughout the 2004-2012 study period. The results serve as an added broad area monitoring tool for water resource managers and present new insight into the initiation and propagation of cyanobacteria blooms in Daecheong reservoir.