• Journal of ILASS-Korea
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• v.28 no.1
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• pp.10-15
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• 2023

Recently, various types of towels and dishcloth dryer products are being widely distributed in Korea. Evaluation methods for water absorption properties of various fabrics have been developed, and there are many studies using them. This study newly intended that whether it is possible to obtain data that can quantitatively analyze the water absorption characteristics of various fabrics, to show the correlation between the water absorption height and the amount of water (water holdup) absorbed, and to experimentally suggest the applicability to evaluate the drying capacity of towel dryer using IR camera. Through these experiments, it was confirmed that quantitative data on the water absorption height of various fabrics can be measured using an IR camera and can be clearly applied to the performance evaluation of actual products.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.453-465
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• 2007

With rapid expansion of the water market and growth of water companies, the recent trends in international water industry show that standardization of service activities concerning management of water and wastewater system (ISO/TC 224, to be issued in the second half year of 2007) is expected to have a large influence on the global water market including liberalization of water service market. In the Draft International Standard(DIS) of ISO/TC224, Performance Indicators(PIs) are suggested to estimate the service activities relating to water and wastewater treatment facilities. PIs have been developed in many countries including some international organization(World Bank, IWA and etc.) for service benchmarking. To evaluate public service level and establish plans to improve service level of wastewater utilities, we developed PIs for 120 items and applied them to 10 sewage utilities in the consideration of their scales, circumstances and conditions. In this study, we verified the applicability of the developed performance indicators(PIs). So, we concluded that PIs developed for the purpose of this study can be a useful tool applicable to objective evaluation of the service level of sewage utilities. Using the evaluation tool of PIs developed, it can also be used as a benchmarking tool in this industry as well as for enhancing the efficiency of operation and management of the sewage system. It will also contribute to the water resource management through determination of investment priorities based on the evaluation results and to raising international competitiveness of the domestic sewage utilities to meet the future opening of the water market.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.864-868
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• 2008

Water transmission and distribution systems play a important role to deliver safe and clean water and are responsible for the most direct impacts of water utilities to customers. Although the performance of WDS(Water Distribution Systems) should be evaluated by a certain standards, interests has not been in WDS and developed due to invisible, hard-working and insufficient information in the evaluation process in Korea till now. The investigations and researches were carried out to develop software to assist the evaluation of WDS with respects to hydraulics, water quality and structural analysis methods. The methodologies have been developed which can be used to estimate the performance to water distribution network and software are implemented by the process. Developed systems are consisted with database, analysis techniques, simulation models, decision support systems and other tools. The concepts and functions are introduced in this paper and the performance index are discussed for accurate assessment of water distribution systems.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.256-267
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• 2022

This study analyzed the current status and trend of water quality using long-term water quality monitoring data measured over the past 5 years in the Seohwacheon Basin, located upstream of Daecheong Lake. In the Seohwacheon Basin, a project is underway to reduce the occurrence of algal blooms in the Daecheong Lake and to improve water quality, and continuous management is required for water quality management. The current water quality evaluation aims to identify the water quality management point, and the good water grade and the integrated water quality index (WQI) were used. For trend evaluation, the effect of the water quality improvement project was evaluated using the Mann-Kendall test and Sen's Slope. As a result of the evaluation, the current water quality index was used to identify the watersheds and when to manage water quality, and the effect of the improvement project was confirmed through trend analysis. Through this study, it is possible to review the water quality status and improvement effect using long-term water quality monitoring data, so it is expected to be applicable to similar types of watersheds in the future.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.101-112
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• 2007

In this study, a methodology was developed to evaluate the effects produced in the event of joint-operation of dams from the viewpoint of water use. It was applied to evaluating the actual results of dam operation in the Han River basin. In order to evaluate the effects of real joint-operation in terms of water supply and flow conditions, the methodology used the satisfaction rate of water requirement and the stability of flow conditions at the evaluation site as indicator. In order to evaluate the effects of joint-operation in terms of power generation, the total power generation produced by dams was used as evaluation indicator. Actual operation results were evaluated by comparison of evaluation indicators relating to single dam operation by which the notified mont of water was supplied, as well as to optimization models. Results of actual joint-operation of the Han River basin, from 2001 to 2004, were compared yearly with results from single operation and optimization model; in terms of water supply, the satisfaction ratio of water requirement stood at $94.36{\sim}99.68%$ for single operation, $97.16{\sim}99.90%$ for actual joint-operation, and 100.0 % for optimization model for all four years. The stability of flow condition was evaluated by the coefficient of river regime and coefficient of flow conditions definitely, indicating that flow conditions were more stable in case of actual operation and optimization models than in case of single operation. The actual total power generation was compared with that generated by other operation rules, indicating that the optimization model increased the power generation by $-3.47{\sim}6.54%$ compared with the actual total power generation, and that the single operation decreased the power generation amount by $12.68{\sim}38.94%$ compared with the actual total power generation.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.521-534
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• 2020

In this study, the variation of water quality was analyzed for six sites in major tributaries of the Nakdong River Basin. Standard-FDC (Flow Duration Curve) was developed using PM (Percentile Method), one of the statistical FDC estimation methods. The LDC (Load Duration Curve) was obtained using the developed FDC. The current method and the LDC evaluation method were compared and analyzed to evaluate the achievement of TWQ (Target Water Quality). Regarding the monthly flow rate variation, the five sites showed the distribution of the lowest flow rate between May and June, indicating a high probability of dry weathering of the streams. The variation of water quality confirmed the vulnerable timing of flow rate in each site, and it is therefore deemed necessary to plan to reduce T-P and TOC. A comparison and evaluation of TWQ showed that there was a difference between the TWQ values achieved by the two techniques. In addition, the margin ratio to the 50% excess ratio can be found in the LDC evaluation. The results of the LDC evaluation by section and by month showed whether or not the water quality was exceeded by flow conditions, along with the vulnerable sections and timing. Accordingly, it is judged that this method can be used for water quality management in TMDLs (Total Maximum Daily Loads).

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.748-756
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• 2006

Accurate and timely information on status and trends in the environment is necessary to shape sound water quality management policy and to implement water quality improvement programs efficiently. One of the most effective ways to communicate information on water quality trends to policy-makers, scientists, and the general public is with comprehensive water quality indices. The derivation and structure of a water quality index (WQI) for the classification of surface water quality is discussed. The WQI generally developed through the selection, transformation and weighting of determinants with rating curves based on legal standards and quality directives or guidelines. The representative pollutants should be included in the index, and the relationship between the quantity of these pollutants in the water and the resulting quality of the water should be based on scientific results. The WQI be simply and meaningfully formulated that nonscientifically trained users can easily become familiar with the framework of the system and use the output data to evaluate their own pollution problems.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.417-430
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• 2009

A BNR comprehensive performance evaluation (BNR CPE) system was established employing system-oriented evaluation methodology for biological nutrient removal (BNR) processes based on the CPE techniques developed by U.S. EPA for evaluation of conventional biological processes. The BNR CPE system applied to five domestic BNR plants adopting $A^2/O$ process confirmed that all target plants except the smallest one had not any serious defective performance and process stability was enhanced with increasing plant size. The system also clearly verified relatively poor performances in anoxic reactors without exception mainly due to influent carbon limit rather than functional defect. Consistent good performances were confirmed even during both winter season and wet weather generally known to be difficult to achieve satisfactory removals. Presentation of evaluation results by modified radar chart system simplified and clarified the evaluation and analysis procedures. The BNR CPE system could not only discover readily the causes of present and prospective poor performances but also facilitate the suggestion of their optimization options. Mutual effect and cause-and-effect among operation parameters and unit processes were also found easily using the evaluation system. The system justified that the adverse effect of defective operating parameters could be compensated by other favorable parameters, especially in anaerobic and anoxic reactors as well as during the winter season.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.4
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• pp.9-18
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• 2012

In this study, a shaking table test was performed for the evaluation of water extinguishing facilities. Water extinguishing facilities, such as a general pipe, a seismic pipe (Loof type) and a pump, were used in the experiment. This captured the dynamic characteristics of water extinguishing systems by earthquake records at El-Centro with a 50%, 70%, 100%, 120% level. As a result, seismic type facilities have excellent seismic performance compared to general facilities. By using the acceleration response spectrum, not only is the performance evaluation of water extinguishing facilities able to be determined, but also the deformation of facilities in low earthquake levels can be known. This proposed approach can determine the seismic performance evaluation of water extinguishing facilities and verify seismic performance criteria.

• Journal of the Korean Data and Information Science Society
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• v.16 no.2
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• pp.349-357
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• 2005

Principal component analysis(PCA) was carried out to evaluate the water quality with the monitering data collected from 1997 to 2003 along the coastal area of Ulsan, Korea. To enhance evaluation and to complement descriptive power of traditional PCA, optimal scaling was applied to transform the original data into optimally scaled data. Cluster analysis was also applied to classify the monitering stations according to their characteristics of water quality.