• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.183-183
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• 2023

Smart water cities (SWC) are urban municipalities that utilizes modern innovations in managing and preserving the urban water cycle in the city; with the purpose of securing sustainability and improving the quality of life of the urban population. Understanding the different urban water characteristics and management strategies of cities situate a baseline in the development of evaluation scheme in determining whether the city is smart and sustainable. This research herein aims to develop measurements and evaluation for SWC Key Performance Indicators (KPIs), and set up a unified global standard and certification scheme. The assessment for SWC is performed in technical, as well as governance and prospective aspects. KPI measurements under Technical Pillar assess the cities' use of technologies in providing sufficient water supply, monitoring water quality, strengthening disaster resilience, minimizing hazard vulnerability, and maintaining and protecting the urban water ecosystem. Governance and Prospective Pillar on the other hand, evaluates the social, economic and administrative systems set in place to manage the water resources, delivering water services to different levels of society. The performance assessment is composed of a variety of procedures performed in a quantitative and qualitative manner, such as computations through established equations, interviews with authorities in charge, field survey inspections, etc. The developed SWC KPI measurements are used to evaluate the urban water management practices for Busan Eco Delta city, a Semulmeori waterfront area in Gangseo district, Busan. The evaluation and scoring process was presented and established, serving as the basis for the application of the smart water city certification all over the world. The established guideline will be used to analyze future cities, providing integrated and comprehensive information on the status of their urban water cycle, gathering new techniques and proposing solutions for smarter measures.

• 한국약용작물학회지
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• 제26권2호
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• pp.181-187
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• 2018

Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate ($P_{N\;max}$), stomatal conductance ($g_s$), stomatal transpiration rate (E), and intercellular $CO_2$ concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in $g_s$ to reduce transpiration. Particularly, E and $g_s$ were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of -0.30 MPa at full turgor and -0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity ($E_{max}$) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.

• Advances in concrete construction
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• 제6권1호
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• pp.47-68
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• 2018

This article reports the utilization of fly ash (FA) waste product from industry and silpozz which is an agro-waste from agriculture as an environmental friendly material in construction industry. The evaluation of strength and durability study was observed using FA and silpozz as a partial replacement of Ordinary Portland Cement (OPC). The studied parameters are compressive strength, flexural strength, split tensile strength and bond strength as well as the durability study involves the acid soluble chloride (ASC), water soluble chloride (WSC), water absorption and sorptivity. Scanning electron microscopy (SEM) and XRD of selected samples are also done. It reveals from the test results that the deterioration factor (DF) in compressive strength is 4% at 365 days. The DF of split tensile strength and flexural strength is 0.96% and 0.6% at 90 days respectively. The minimum slip is 1mm and 1.1mm after 28 days of testing bond strength for NWC and SWC sample respectively. The percentage decrease in bond strength is 10.35% for 28 days SWC samples. The pre-cast blended concrete samples performed better to chloride diffusion. Modulus of elasticity of SWC samples are also studied.The water absorption and sorptivity tests are conducted after 28 days of curing.

• Journal of information and communication convergence engineering
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• 제20권1호
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• pp.49-57
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• 2022

Fertilizers have long been used to increase crop yields; however, farmers are still having difficulties in managing fertilizers for growing crops as well as economic problems. The conventional method of soil sampling and laboratory analysis to determine soil pH is time consuming and costly; therefore, a portable pH sensor is developed to characterize spatial or temporal variability within fields via rapid and dense data acquisition. The portable pH sensor comprises an electrode unit, a portable console, and a USB connector. The soil water content (SWC) and electrical conductivity (EC) affect the electrical resistance of soil. An artificial test soil is performed to evaluate the effect of SWC and EC on soil pH. The test results show that stable pH measurements are achieved at SWCs greater than 20 mL (16.3%). Regardless of the SWC, the electric potential difference (EPD) remains at 2.5 g of NaCl. As the EC increases in the soil samples, the EPD increases.

• 한국기계가공학회지
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• 제4권4호
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• pp.48-53
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• 2005

This research is materialized the mechanism of a interlocking elevator device to meet with customer's requirement demanding a variety of function. On this suitably theoretical translation and by considering of material significance of the most factor's tension spring and torsion spring, it's compared and reviewed the stress's calculation according that SWC and SWPB applied differently. And also that is approved through actual experiment. Out of a variety of feasible movement. Torque Balance is materialized by combination of tension spring, torsion spring and disk spring. So that application of 3 factors for optimal design is very important factor. In future, this research thesis make sure to play a highly role for application and improvement mechanically in various industry sector out of materializing interlock.

• 상하수도학회지
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• 제29권4호
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• pp.511-517
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• 2015

Korea's modern waterworks began with construction of DDukdo water treatment plant in 1908 and has been growing rapidly along with the country's economic development. As a result, water supply rates have reached 98.5% based on 2013. Despite multilateral efforts for high-quality water supply, such as introduction of advanced water treatment process, expansion of waterworks infrastructure and so on, distrust for drinking tap water has been continuing and domestic consumption rate of tap water is in around 5% level and extremely poor comparing to advanced countries such as the United States(56%), Japan(52%), etc. Recently, the water management has been facing the new phase due to water environmental degradation caused by climate change, aging facilities, etc. Therefore, K-water has converted water management paradigm from the "clean and safe water" to the "healthy water" and been pushing the Smart Water City(SWC) Pilot Project in order to develop and spread new water supply models for consumers to believe and drink tap water through systematic water quality and quantity management combining ICT in the whole water supply process. The SWC pilot projects in Pa-ju city and Go-ryeong county were an opportunity to check the likelihood of the "smart water management" as the answer to future water management. It is needed to examine the necessity of smart water management introduction and nationwide SWC expansion in order to improve water welfare for people and resolve domestic & foreign water problems.

• Journal of Ecology and Environment
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• 제35권3호
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• pp.213-225
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• 2012

Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.

• 한국환경과학회지
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• 제19권6호
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• pp.689-701
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• 2010

The effects of high-resolution wind profiler (HWP) data on the wind distributions were evaluated in two different coastal areas during the study period (23-26 August, 2007), indicating weak-gradient flows. The analysis was performed using the Weather Research and Forecasting (WRF) model coupled with a three-dimensional variational (3DVAR) data assimilation system. For the comparison purpose, two coastal regions were selected as: a southwestern coastal (SWC) region characterized by a complex shoreline and a eastern coastal (EC) region surrounding a simple coastline and high mountains. The influence of data assimilation using the HWP data on the wind distributions in the SWC region was moderately higher than that of the EC region. In comparison between the wind speed and direction in the two coastal areas, the application of the HWP data contributed to improvement of the wind direction distribution in the SWC region and the wind strength in the EC region, respectively. This study suggests that the application of the HWP data exerts a large impact on the change in wind distributions over the sea and thus can contribute to the solution to lack of satellite and buoy data with their observational uncertainty.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.505-505
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• 2022

This study shows the first output of the three-year project (2021-2023) to develop a Smart Water City (SWC) Global Standard and Certification Scheme ley by K-water, International Water Resources Association (IWRA) and Asia Water Council (AWC). There are three major parts in the first year. In Part 1, it investigates the essential features of cities today and details the water challenges currently faced and likely to be confronted in the future. It also investigates the functions that water fulfills in the urban environment, and how ICTs can contribute to improving those functions by each Urban Water Cycle. A definition of a Smart Water City is proposed following a discussion on the meaning of "smart development". This part of the report also presents different city cases from countries around the world to illustrate the urban water challenges and the technological and non-technological solutions that cities have put in place, including national and/or local policies and strategies. In Part 2, it defines what global standards indicators and certification schemes are and identifies their characteristics. Especially, it analyses in detail eight relevant standards and certification schemes measuring sustainable development and/or water resources management in urban settings. Standards elaborated by international organizations are distinguished from those developed by the private sector, non-governmental organizations, and by academia. Finally, this study suggests the right direction to develop SWC global standard frameworks and certification schemes. And then, it shows the main tasks for the Stage 2 (second year) project. Basically, the framework for a future SWC standard (consisting three main pillars: Technical, Governance and Prospective pillars) will be fully defined in Stage 2.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2137-2142
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• 2003

One of the important performance metrics of the World Wide Web is how fast and precise a request from users will be serviced successfully. Shared Web Caching (SWC) is one of the techniques to improve the performance of the network system. In Shared Web Caching Systems, the key issue is on deciding when and where an item is cached, and also how to transfer the correct and reliable information to the users quickly. Such SWC distributes the items to the proxies which have sufficient capacity such as the processing time and the cache sizes. In this study, the Hot Spot Prediction Algorithm (HSPA) has been suggested to improve the consistent hashing algorithm in the point of the load balancing, hit rate with a shorter response time. This method predicts the popular hot spots using a prediction model. The hot spots have been patched to the proper proxies according to the load-balancing algorithm. Also a simulator is developed to utilize the suggested algorithm using PERL language. The computer simulation result proves the performance of the suggested algorithm. The suggested algorithm is tested using the consistent hashing in the point of the load balancing and the hit rate.