• Journal of the Korean Graphic Arts Communication Society
• /
• v.20 no.1
• /
• pp.16-27
• /
• 2002

Recently, the attraction for water-based ink is increasing, Because Solvent ink, based on organic solvent, cause bad effect on environment and rise the cost. Instead of organic solvent that cause environment pollution as well as cost-rise by rise of petroleum price, Binder based on alkali-soluble resin is popular and studied by many other country. However, in domestic, research and development for alkali-soluble resin is not like, because of lack of understanding environmental pollution and safety, therefor alkali-soluble resin development and research for the properties of the water-based ink used by alkali-soluble resin is not study very well. In this paper, we studied dispersion of carbon black in acrylic resin solution and the properties of water-based ink used by carbon black and acrylic binder.

• Journal of the Korea Furniture Society
• /
• v.17 no.3
• /
• pp.87-94
• /
• 2006

The purpose of this study was to evaluate the relationships between the mixing ratio and water vapor sorption property of charcoal-based loess composites for furniture & building materials with environmental friendly. Charcoal-based loess composite can be easily made by blending method with water. But the composites had much brittle fracture pattern with the increase of charcoal content. That is due to the lack of loess that takes linkage role of composites. In water vapor sorption properties, adsorption ability of charcoal was about six times higher than that of loess. Therefore, vapor sorption ability was maximum at the mixture ratio of charcoal 80% and loess 20%. It is considered that wood charcoal based inorganic composite materials can be used for various purposes as a building interior & exterior and furniture members.

• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.2
• /
• pp.107-113
• /
• 2018

Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

• Ocean and Polar Research
• /
• v.38 no.4
• /
• pp.331-338
• /
• 2016

Many studies using tracers have been conducted to understand a physical process in a system. Rain-on-snow could accelerate snowmelt processes, which influences the hydrological process in both temperate and polar regions. Hydrological and ecological conditions will be affected by the amount and timing of discharge reaching the bottom of a snowpack. The discharge consists of the rain-on-snow, pore water penetrating into the snowpack and natural meltwater. In this study, after a rain-on-snow experiment, we conducted an isotopic hydrograph separation to distinguish rainwater and pore water from meltwater. Using the isotopic data of snow and meltwater from Lee et al. (2010), two components were separated based on the assumption that rainwater and pore water are new water and natural meltwater is old water. After the second rain-on-snow experiment, the maximum contributions of rainwater and pore water reached up to 69% of the discharge and then decreased. During the study period, the measured total discharge was 4153 L and 40% (based on hydrogen isotope) of rainwater and pore water was calculated in the discharge, which is not consistent with what Lee et al. (2016) calculated using chemical separation (63%). This inconsistency can be explained by how an end-member was defined in both approaches. The contributions of artificial rainonsnow and pore water to melwater discharge range between the two methods. This study will suggest a mixing calculation from isotopic compositions of the Southern Ocean.

• Journal of Korean Society on Water Environment
• /
• v.23 no.1
• /
• pp.103-110
• /
• 2007

An efficient operational strategy using expert system for metro water supply systems in case of emergency situations is developed in this study. The emergency situations of the water supply systems are classified into three categories : pipeline system accident, machinery and electric facility accident and water quality accident. A PC-based expert system is developed using CLIPS for Seoul metro water supply system, Phase 1 & 2 system and Phase 3 & 4 system. Broad professional knowledges and experiences from the experts in the water supply systems have been collected systematically to construct the knowledge base. Decision-making in case of an emergency is based upon the professional knowledge so that a rational and efficient operational management can be available even in the absence of experienced expert. Especially the expert model developed in this study also provides a guide for pumping operation in case of pipeline accident to confirm that the proper pressure to all nodes in the system is supplied. The pipe network simulator KYPIPE has been consecutively executed by trial and error fashion for each pipeline in the system. The results from KYPIPE were included in the knowledge base to supplement the knowledge of the field engineers.

• Journal of Korean Society on Water Environment
• /
• v.30 no.4
• /
• pp.409-417
• /
• 2014

Spatial prediction methods have been useful to determine the variability of water quality in space and time due to difficulties in collecting spatial data across extensive spaces such as watershed. This study compares two kriging methods in predicting BOD concentration on the unmonitored sites in the Geum River Watershed and to assess its predictive performance by leave-one-out cross validation. This study has shown that cokriging method can make better predictions of BOD concentration than ordinary kriging method across the Geum River Watershed. Challenges for the application of cokriging on the spatial prediction of surface water quality involve the comparison of network-distance-based relationship and euclidean-distance-based relationship for the improvement in the predictive performance.

• Journal of Korean Society of Water and Wastewater
• /
• v.31 no.3
• /
• pp.249-256
• /
• 2017

Recently, application areas based on M2M (Machine-to-Machine communications) and IoT (Internet of Things) technologies are expanding rapidly. Accordingly, water flow and water quality management improvements are being pursued by applying this technology to water and sewage facilities. Especially, water management will collect and store accurate data based on various ICT technologies, and then will expand its service range to remote meter-reading service using smart metering system. For this, the error in flow rate data transmitting should be minimized to obtain credibility on related additional service system such as real time water flow rate analysis and billing. In this study, we have identified the structural problems in transmitting process and protocol to minimize errors in flow rate data transmission and its handling process which is essential to water supply pipeline management. The result confirmed that data acquisition via communication system is better than via analogue current values and pulse, and for communication method case, applying the industrial standard protocol is better for minimizing errors during data acquisition versus applying user assigned method.

• Geomechanics and Engineering
• /
• v.28 no.6
• /
• pp.573-584
• /
• 2022

Water inrush may occur during seaside urban tunnel excavation. Various factors affect the water inrush, and the water inrush mechanism is complex. In this study, nine evaluation indices having potential effects on water inrush were analysed. Specifically, the geographic and geomorphic conditions, unfavourable geology, distance from the tunnel to sea, strength of the surrounding rock, groundwater level, tidal action, cyclical footage, grouting pressure, and grouting reinforced region were analysed. Furthermore, a two-step interval risk assessment method for water inrush management during seaside urban tunnel excavation was developed by a multi-index system and interval risk assessment comprised of an interval analytic hierarchy process, fuzzy comprehensive evaluation, and relative superiority analysis. The novel assessment method was applied to the Haicang Tunnel successfully. A preliminary interval risk assessment method for water inrush was performed based on engineering geological conditions. As a result, the risk level fell into a risk level IV, which represents a section with high risk. Subsequently, a secondary interval risk assessment method was performed based on engineering geological conditions and construction conditions. The risk level of water inrush is reduced to a risk level II. The results agreed with the current tunnel situation, which verified the reliability of this approach.

• Journal of Korean Society on Water Environment
• /
• v.39 no.4
• /
• pp.261-268
• /
• 2023

The benthic macroinvertebrates index (BMI) was developed based on the 5-day biochemical oxygen demand (BOD₅), which is the amount of biodegradable organic matter in stream water. However, benthic macroinvertebrates mainly live in the streambed substrate and are affected by the interaction of water quality and substrate. This study was conducted to examine the interactive relationship between water quality items (BOD₅, total phosphorus (TP), total suspended solids (TSS)) and substrate with BMI by performing statistical analyses (four-way analysis of variance, Pearson's correlation analysis, partial correlation analysis and multiple regression analysis). The data used in the analyses were collected from 19,915 sampling units at 1,937 sites in South Korea from 2010 to 2020. The interaction effect between BOD₅ and substrate types was confirmed through a four-way analysis of variance. Partial correlation analysis and multiple regression analysis estimated the degree of influence on the change in BMI value in the order of mean grain size of the substrate as (𝜱_m) > BOD₅ > TP > TSS. BMI can be regarded as an index that evaluates the comprehensive effects of water quality and streambed status, although it is an index that was developed based on the amount of biodegradable organic matter in a water column.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.43-46
• /
• 2022

The optimal operation of the water purification plant can be carried out only when the required flow rate is supplied in a timely manner using the minimum electrical energy by accurately predicting the pattern and amount of tap water used in the consumer. In order to ensure the stability of tap water production and supply, a system that can be pre-verified before applying AI-based composite sensors to the water purification plant was established to derive complementary matters through the pre-verification model for each composite sensor and improve the quality and operation stability of the composite sensor data.