• Proceedings of KOSOMES biannual meeting
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• 2001.05a
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• pp.105-133
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• 2001

World trade has been increasing continuously in total volume, on the other hand, environmental protection on sea and conservation of fishery resources has been rising up the major issue. All of the world are pushing their efforts two major purposes to the full, one is taking competitive place in marine transportation throughout the world and another Is environment protection. Pusan Port as world leading Port put its all effort in bring more ocean going vessels and securing their traffic route by providing them more information related marine traffics through PTMS in port. During two years of operation, statistics of marine traffic accidents showed that many dynamic casualties such as collisions, groundings, and rammings has been decreased. However, due to increasing cargo volume, limited water area and unpredictable weather condition, potential risks still exist high. In this paper, in order to maximize the efficiency of PTMS and reduce various risks in the future, we examine risk factors over operational results and experience, and propose reasonable operational methods of PTMS.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.93-100
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• 2016

Since the sodium-cooled fast reactor is operated in a hostile environment due to the use of liquid sodium as its coolant, advanced techniques for in-service inspection are required to periodically verify the integrity of the reactor. This paper presents the development of in-service inspection techniques for Proto-type Generation IV Sodium-cooled Fast Reactor. First, the 10 m long plate-type ultrasonic waveguide sensor has been developed for in-service inspection of reactor internals, and its feasibility was verified through several under-water and under-sodium experiments. Second, the combined inspection system for in-service inspection of ferromagnetic steam generator tubes has been developed. The remote field eddy current testing and magnetic flux leakage testing can be conducted simultaneously by using the developed inspection system, and the detectability was demonstrated through several damage detection experiments. Finally, the electro-magnetic acoustic transducer which can withstand high temperature and be installable in the remote operated vehicle has been developed for in-service inspection of the reactor vessel, and its detectability was investigated through damage detection experiments.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.141-150
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• 2021

With the recent spread of the concept of Smart Cities which is to solve urban problems with ICT technology, Living Lab, which identifies the demands of citizens who dwell in the city and verifies the acceptability of the services being introduced, has become an important topic. Living Lab is an open innovation platform introduced in consideration of the user's perspective in real life and is a new approach in that service developers use collective intelligence in the process of Co-creation with users. Living Lab is operated on topics which is close to citizens' daily lives such as energy, housing, transportation, and education. In particular, as energy and environmental-focused Living Lab emerges in accordance with the 'Korean New Deal Policy', interest and importance in the field are increasing. The paper derives the characteristics of water resource Living Lab through case analysis of several Living Lab practices. Water resource Living Lab in Daejeon and Chuncheon, which are located in Korea, and water resource Living Lab in Romania and Indonesia are covered in this paper as the reference. The paper finally analyzes the case of Sambang Water Living Lab in Gimhae, which is the city located in southern part of Korea. As a result of case analysis, the urban water resource Living Lab focuses on the raw water of urban water resource and should respond sensitively to the safety of citizens. And for the success of this urban water resource Living Lab, it is essential to ensure that citizens participating in the Living Lab clearly understand the concept of water resources, and citizens' opinions to be implemented as services.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.183-201
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• 2018

The tolerance of Korean benthic macroinvertebrates to organic pollution has been analyzed since the early 1990s. However, considering the fact that there have been related studies carried out in some European countries since the early 20th century, the history of the research in Korea is very short and there is still much knowledge to supplement. We revised the saprobic valency, the saprobic value and the indicator weight value of 190 benthic macroinvertebrates taxa through the data of water quality and individual abundance collected from 7,086 sampling units in Korea from 2008 to 2014. The individual abundance of Uracanthella (Ephemeroptera) as a representative, one of the most common and abundant taxa in Korea, showed a typical lognormal distribution to 5-day biochemical oxygen demand (BOD5) concentration, and a normal distribution to the class interval of BOD5 concentration according to saprobic series. The value combining the mean individual abundance and the relative frequency of occurrence was a more efficient indicator value than that of each property alone. Benthic Macroinertebrates Index (BMI) was newly proposed as a modification of the saprobic index of Zelinka and Marvan (1961). BMI showed extremely significant correlation (determination coefficient $r^2$ > 0.6, n = 569 sites) with the concentration of BOD5, and the coefficient was a little higher than those of the previous indices. Until now, there has been very little research on the assessment of biological integrity of benthic macroinvertebrates community in Korea. While continuing researches into improve the reliability of BMI, it is necessary to develop multimetric indices for evaluating the integrity, including the composition of species and functional guilds, and the richness and diversity of the community.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.9-21
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• 2020

The proper operation and safety management of water and wastewater treatment systems are essential for providing stable water service to the public. However, various natural disasters including floods, large storms, volcano eruptions and earthquakes threaten public water services by causing serious damage to water and wastewater treatment plants and pipeline systems. Korea is known as a country that is relatively safe from earthquakes, but the recent increase in the frequency of earthquakes has increased the need for a proper earthquake management system. Interest in research and the establishment of legal regulations has increased, especially since the large earthquake in Gyeongju in 2016. Currently, earthquakes in Korea are managed by legal regulations and guidelines integrated with other disasters such as floods and large storms. The legal system has long been controlled and relatively well managed, but technical research has made limited progress since it was considered in the past that Korea is safe from earthquake damage. Various technologies, including seismic design and earthquake forecasting, are required to minimize possible damages from earthquakes, so proper research is essential. This paper reviews the current state of technology development and legal management systems to prevent damages and restore water and wastewater treatment systems after earthquakes in Korea and other countries. High technologies such as unmanned aerial vehicles, wireless networks and real-time monitoring systems are already being applied to water and wastewater treatment processes, and to further establish the optimal system for earthquake response in water and wastewater treatment facilities, continuous research in connection with the Fourth Industrial Revolution, including information and communications technologies, is essential.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.177-186
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• 2015

The main objective of this study was to assess the applicability of IoT (Internet of Things)-based flood management under climate change by developing intelligent water level monitoring platform based on IoT. In this study, Arduino Uno was selected as the development board, which is an open-source electronic platform. Arduino Uno was designed to connect the ultrasonic sensor, temperature sensor, and data logger shield for implementing IoT. Arduino IDE (Integrated Development Environment) was selected as the Arduino software and used to develop the intelligent algorithm to measure and calibrate the real-time water level automatically. The intelligent water level monitoring platform consists of water level measurement, temperature calibration, data calibration, stage-discharge relationship, and data logger algorithms. Water level measurement and temperature calibration algorithm corrected the bias inherent in the ultrasonic sensor. Data calibration algorithm analyzed and corrected the outliers during the measurement process. The verification of the intelligent water level measurement algorithm was performed by comparing water levels using the tape and ultrasonic sensor, which was generated by measuring water levels at regular intervals up to the maximum level. The statistics of the slope of the regression line and $R^2$ were 1.00 and 0.99, respectively which were considered acceptable. The error was 0.0575 cm. The verification of data calibration algorithm was performed by analyzing water levels containing all error codes in a time series graph. The intelligent platform developed in this study may contribute to the public IoT service, which is applicable to intelligent flood management under climate change.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.484-491
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• 2012

The hydrological components of a sandy loam soil of nearly level in Chuncheon over 30 years were computed using the E-DiGOR model. Daily simulations were carried out for each year during the period of 1980 to 2009 using standard climate data. Reference evapotranspiration and potential soil evaporation based on Penman-Montheith model were higher during May to August because of the higher atmospheric evaporative demand. Actual soil evaporation was mainly found to be a function of the amount and timing of rainfall, and presumably soil wetness in addition to atmospheric demand. Drainage was affected by rainfall and increased with a higher amount of precipitation and soil water content. Excess drainage occurred throughout rainy months (from July to September), with a peak in July. Therefore, leaching may be a serious problem in the soils all through these months. The 30-year average annual reference evapotranspiration and potential soil evaporation were 951.5 mm and 714.2 mm, respectively. The actual evaporation from bare soil varied between 396.9-528.4 mm and showed comparatively lesser inter-annual variations than drainage. Annual drainage rates below 120 cm soil depth ranged from 477.8 to 1565.9 mm. The long-term mean annual drainage-loss was approximately two times higher than actual soil evaporation.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.517-523
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• 2014

In order to remove both nitrate and sulfate present in the concentrate of RO(reverse osmosis) process, a combined bio-regeneration and ion-exchange(IX) system was studied. For this purpose, both denitrifying bacteria(DNB) and sulfate reducing bacteria(SRB) were simultaneously cultivated in a bio-reactor under anaerobic conditions. When the IX column containing a nitrate-selective A520E resin was fully exhausted by nitrate and sulfate, the IX column was bio-regenerated by pumping the supernatant of the bio-reactor, which contains MLSS concentration of $125{\pm}25mg/L$, at the flowrate of 360 BV/hr. Even though the nitrate-selective A520E resin was used, the breakthrough curves of ionic species showed that sulfate was exhausted earlier than nitrate. The reason for this result is due to the fact that the concentration of sulfate in RO concentrate was 36 to 48 times higher than nitrate. The bio-reactor was successfully operated at a volumetric loading rate of 0.6 g $COD/l{\cdot}d$, nitrate-N loading rate of 0.13 g $NO_3{^-}-N/l{\cdot}d$, and sulfate loading rate of 0.08 g $SO_4{^{2-}}/l{\cdot}d$. The removal rate of SCOD, nitrate-N, sulfate was 90, 100, and 85%, respectively. When the virgin resin was fully exhausted and consecutively bio-regenerated for 2 days, 81% of nitrate and 93% of sulfate were reduced. When the virgin resin was repeatedly used up to 4 cycles of service and bio-regeneration, the ion-exchange capacity of bio-regenerated resin decreased to 95, 91, 88, and 81% of virgin resin.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.573-576
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• 2006

To predict service life of concrete structures exposed to chloride attack, surface chloride concentration, diffusion coefficient of chloride ion, and chloride corrosion threshold value in concrete, are used as important factors. of these, as the diffusion coefficient of chloride ion for concrete is strongly influenced by concrete quality and environmental conditions of structures and may significantly change the service life of structures, it is considered as the most important factor for service life prediction. The qualitative factors affecting the penetration and diffusion of chloride ion into concrete are water-binder(W/B) ratio, age, cement type and constituents, chloride ion concentration of given environment, wet and dry conditions, etc. In this paper the influence of cement type on the diffusion characteristics of chloride ion in concrete was investigated through the chloride ion diffusion test. For this purpose, the diffusion characteristics in concrete with cement type such as ordinary portland cement(OPC), binary blended cement(BBC), and ternary blended cement(TBC) were estimated for the concrete with W/B ratios of 32% and 38%, respectively. It was observed from the test that the difussion characteristics of BBC containing OPC and ground granulated blast-furnace slag was found to be most excellent of the cement type used in this study.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.360-366
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• 2008

The spatial and temporal variations of the high turbid water by a single event of heavy rain (total 299.1 mm and daily maximum 99.4 mm) were studied in Andong Reservoir, which has hypolimnetic discharges. Turbid water entered into the reservoir, was isolated from the bottom at the midreservoir and then passed through the metalimnion as an interflow current in the lacustrine zone. Maximum turbidity was 290 NTU at 16 m depth of the midreservoir, but the initial turbidity showed about 10 NTU in the reservoir before the rainfall. Turbid water in the reservoir affected to increase the withdrawal turbidity from the 3rd day after the rainfall, the maximum turbidity was 129 NTU at 5th day after the rainfall. Turbid water that flew towards the downreservoir distributed within 5 m above the outlet gate of the intake tower, showing the maximum turbidity, and that was decreased in its thickness and concentration by discharging through the intake tower. It has taken 38 days until the turbidity in the withdrawal reduced to 30 NTU, and 87 days to reduce the turbidity to the way when it was before the rainfall, with the correlation coefficient of 0.96 and 0.97, respectively. Turbid water was withdrawn from the reservoir by entraining into the intake tower as a form of the interflow, and not be settled down to the bottom of the reservoir. Therefore, we assessed that the depth of the withdrawal was appropriately positioned in Andong Reservoir, so as to withdraw the turbid water effectively from the reservoir.