• Title/Summary/Keyword: 배수성

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Comparing Methods for Determining Flood Protection Elevation in Urban Built-up Areas (도시지역 방어침수위 설정방법 비교분석)

  • Lee, Yang Jae;Shin, Sang Young;Lee, Chang Hee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3B
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    • pp.271-281
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    • 2008
  • To determine the flood protection elevation (FPE) in urban built-up areas, this study examines four possible methods: using the highest flood elevation in the past, extending base flood elevations of nearby watercourse to inland, and two simulation methods of inland flood under the same rainfall used in the watercourse planning nearby. According to the case study of the Jang-An Drainage Area, Seoul, the highest flood elevation in the past and simulation results of inland flood under the same rainfall in the watercourse planning nearby tend to get similar results, while extending base flood elevations of nearby watercourse to inland shows much higher elevations than other results. Meanwhile, cost-benefit analysis, when regulating residential/commercial uses below the FPE by each of four methods, suggest that planners need to consider carefully the economic feasibility of FPE used to choose appropriate methods.

Quantity-based Early Cost Estimation Model for Road Construction Projects (대표물량 기반의 도로공사 설계단계의 개략공사비 예측모델)

  • Kim, Du Yon;Kim, Byungil;Yeo, Donghoon;Han, Seung Heon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.3D
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    • pp.373-379
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    • 2009
  • Cost estimation in the early phase enables government to plan public budgeting more efficiently by providing information about construction cost. However, cost estimation in the early phase is difficult to predict because only a little information can be utilized. The cost estimation method now being used by the government is calculated by length of the road multiplied by unit cost per length and shows high error rate because it cannot reflect the unique characteristics of each project. As the project is being proceeded, level of available information also changed. So, reflecting available information of a project is important. This paper divided early phase into two parts : planning phase and early design phase, and developed cost estimation model considering level of available information of each phase. Total 143 cases are utilized to find influencing variables and develop cost estimation model and model validation is done by adopting required accuracy level. This cost estimation model reflecting level of available information can be applied to public budgeting, feasibility test, and comparison between routes.

Optimal Method for Injection of Neutralizer into Embankment Structure Composed of Pyrite Rocks (황철석으로 조성된 성토구조체의 중화제 주입을 위한 최적 방안 제안)

  • Young-Suk Song;Jung-Mann Yun
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.4
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    • pp.73-82
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    • 2023
  • In this study, the optimal method for injection of neutralizer to restraint the leakage of acid drainage in embankment structure composed of pyrite rocks is proposed. Finite Element Analysis was performed to examine the seepage effect caused by injection of neutralizer into the embankment structure. The diameter of the neutralizer injection hole was selected as 50cm, the interval space of injection ranged from 1m to 4m and the injecting pressure ranged from 100kPa to 220 kPa were applied for the numerical analysis. According to the analysis results, the saturation time of the whole embankment structure was shown to be fast at a relatively low injecting pressure in the case of injecting interval space of 1.0m and injecting pressure of 130kPa and in the case of injecting interval space of 2.0m and injecting pressure of 160kPa. When the interval space of injection for saturation of whole embankment structure is selected as 3m, various injection pressures can be applied from 130kPa to 190kPa, and the saturation time of whole embankment is similar regardless of the injection pressure. Therefore, the optimal method for injection of neutralizer considering economic efficiency was selected as injecting interval space of 3.0m and injection pressure of 130kPa.

Study on the Automatic Hull-form Optimal Design of Container Carriers Using HOTCONTAINER (HOTCONTAINER를 사용한 컨테이너선의 선형 최적 설계에 관한 연구)

  • Hee Jong Choi;Hyoun Mo Ku
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.1
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    • pp.118-126
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    • 2024
  • In this paper, the research contents and results related to the automation of the hull-form optimal design of container ships are summarized. A container ship is a ship that generally operates near Froude number of 0.26. To implement hull-form optimal design automation for ships operating at this speed, an optimization algorithm, a hull-form change algorithm, a ship performance prediction algorithm, an automation algorithm, and an iterative calculation technique were applied to develop a numerical analysis computer program that enables hull-form optimal design automation of the container ship, and it was named HOTCONTAINER. In this study, a sensitivity analysis algorithm was developed and applied to appropriately set design variables for hull-form optimal design. To understand the reliability and real ship applicability of the developed algorithm, a numerical analysis was performed on KCS(KRISO Container Ship), a container ship that has been studied in various ways worldwide. Consequently, the optimal ship was derived, and the wave resistance, wave pattern, and wave height of the target and optimal ship were compared. In conclusion, compared the target ship, the optimal ship a 47.63% decrease in wave resistance, and the displacement and wet surface area decreased by 0.50% and 0.39%, respectively.

An Experimental Study of UX Writing based on Interaction mode in the Automotive Financial Application : Focusing on Terminology Use In Lease service (자동차 금융 애플리케이션의 인터랙션 모드에 따른 UX 라이팅 실험 연구 : 리스 서비스에서 전문용어 사용을 중심으로)

  • Jeongmin Lee;Naeun Yang;Sueun Bae;Junho Choi
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.4
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    • pp.563-574
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    • 2024
  • While the integration of chatbot and the simplification of financial terminology in Financial services' apps are increasingly common, automotive finance apps often show lower user satisfaction for complex terminol- ogy and rigid content. This study investigates the effects of chatbot interaction modes and the simplification of financial terminology on user experience in automotive finance apps. We developed prototypes for car lease tasks under different conditions: the type of user interaction channel (chatbot vs menu-based), and the usage of financial terminology. A 2 x 2 experimental survey was conducted to measure perceptions of friendliness, read- ability, trust, and accuracy. The findings revealed that chatbot interactions significantly enhance friendliness more than menu-based interactions, and simplifying terminology significantly improves readability and friendliness. However, no significant differences were observed in trust and accuracy between the conditions. Furthermore, nosignificant interaction effects were found between the two conditions across all variables. This study contributes by quantitatively assessing the impacts of chatbot consultation modes and terminology sim- plification on customer experience in financial services.

Research on Wave-Making Resistance Reduction Technology for Container Ships (컨테이너선의 조파저항 감소 기술에 대한 연구)

  • Hee Jong Choi
    • Journal of Navigation and Port Research
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    • v.48 no.4
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    • pp.249-260
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    • 2024
  • This paper aimed to summarize research on technologies that could efficiently reduce wave-making resistance of container ships. Tto develop wave resistance reduction technology that could be applied to container ships and use it in real ship design, hull-form optimal design was performed by applying optimization algorithms, hull-form change algorithms, ship performance prediction algorithms, automation algorithms, and iterative optimal design techniques. A computer program was also developed. To properly set design variables known to be important elements in hull-form optimal design and to efficiently set lower and upper limits of design variables, a sensitivity analysis algorithm was developed and applied to hull-form optimal design. To predict the reliability and applicability of the developed computer program for real ships, hull-form optimal design was performed for a KRISO Container Ship (KCS), a container ship with various studies conducted worldwide. Hull-form optimal design was performed at Fn=0.26, the design speed of the KCS ship. Numerical analysis was performed on the hull-form of the target ship, the KCS ship, and the hull-form of the ship derived as a result of the hull-form optimal design to determine wave resistance, wave system, and wave height. The optimal ship's wave resistance was found to be reduced by 80.60% compared to the target ship. The displacement and wetted surface area were also found to be reduced by 1.54% and 1.21%, respectively.

Relationship between Flow Limit and Compression Index for Clayey Soils (점성토의 흐름한계와 압축지수의 상관관계에 관한 연구)

  • Moon, Hong Duk;Hwang, Keum-Bee;Woo, Seung-Wook;Kim, Do-Hyop;Kim, Tae-heon;Park, Sung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.40 no.5
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    • pp.39-49
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    • 2024
  • Obtaining the compression index directly from consolidation tests is time-consuming; thus, it is often estimated using an empirical equation based on the liquid limit. However, the liquid limit measurement can introduce significant errors depending on the instrument or the experimenter. Therefore, this study proposes a new empirical equation for the compression index, utilizing the flow limit, which corresponds to the water content when the undrained shear strength of the clayey soil is zero. To achieve this, clayey soils of various compositions were prepared by mixing sand at proportions of 10, 20, and 30% with calcium-based and sodium-based bentonite. Liquid limit, flow limit, and consolidation tests were subsequently conducted. The results showed that the liquid and flow limits of sodium-based bentonite were 4-7 times higher than those of calcium-based bentonite. Additionally, the compression index differed significantly, ranging from 0.31-4.91. Conversely, regardless of bentonite type, the differences in liquid limit, flow limit, and compression index between the two clayey soils diminished as the sand content increased. The current linear empirical equation for the compression index was found unsuitable for sodium-based bentonite with high liquid limits; hence, a new exponential correlation was proposed. Consequently, the coefficient of determination for the exponential compression index equation based on the liquid limit was 0.81, while the equation using the flow limit achieved a coefficient of determination of 0.98, demonstrating a higher correlation compared to the liquid limit-based equation.

Study on the relationship between the potassium activity ratio of paddy soils and potassium uptake by rice plant (답토양(沓土壤)의 가리(加里) Activity ratio와 수도(水稻)의 가리(加里) 흡수(吸收) 특성(特性)에 관(關)한 연구)

  • Kim, Tai-Soon
    • Korean Journal of Soil Science and Fertilizer
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    • v.9 no.4
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    • pp.223-233
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    • 1976
  • The potassium equilibrium activity ratio ($AR^k_e$) and energies of exchange for replacement of ca+Mg by K ($E_k$) were measured for seven paddy soils to investigate their correlations with the exchangeable K (Kex) and uptake of K at different growth stages of rice plant. It was found that $AR^k_e$ had highly significant correlations at 1% level with uptake of K at maximum tillering, heading and harvesting stages, and also with Kex in soils at maximum tillering stage. The larger $AR^k_e$ of soils, the more uptake of K by rice plant. The fact indicates that uptake of K by the plant can be characterized in terms of $AR^k_e$ or energy of exchange of soils. In aspect of energy of exchange, higher uptake of K and yield of grain were observed from -2500 to -3000 calories per chemical equivalent, representing suitable balances between K and Ca+Mg in soils. Low uptake of K was observed at the energies of exchange below -3500 calories per chemical equivalent, which were prevalent in the ordinary acidic soils. From the correlations between energy of exchange and Kex, it can be concluded that at least 0.37 meq. of exchangeable K should be existed in 100g of dried acidic soil to keep suitable balances of K and Ca+Mg. The result shown that application of K adsorbed zeolite to paddy soils increased $AR^k_e$ and consequently brought about higher K uptake and grain yield. Therefore, a reasonable way recommended to get good balance of exchangeable K in the soil is applying 1.7 tonns of K adsorbed zeolite containing 60kg $K_2O$ per hectare.

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An Application Status and Consideration of System Improvement on the Sea Area Utilization Conference and Impact Assessment (해역이용협의제도 운용 현황 분석 및 실효성 제고방안)

  • Lee, Dae-In;Kim, Gui-Young;Jeon, Kyeong-Am;Eom, Ki-Hyuk;Yu, Jun;Kim, Yeong-Tae;Moon, Ju-Hoon;Kam, Min-Jae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.14 no.4
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    • pp.239-248
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    • 2011
  • This paper evaluated types and characteristics of development projects occurred in coastal area (Public Water) by analyzing an application status of Sea Area Utilization Conference System that effective protect and manage marine environment and ecosystem from various artificial utilization and development enforced in 2008. Also, system improvement for stable settlement and security of efficiency considering exposed problems during system enforcement were diagnosed. The number of Sea Area Utilization Conference (SAUC) performanced during the period of 2009-2010 was 3,705, which consisted of simple SAUC (87.0%), general SAUC (12.8%), and Sea Area Utilization Impact Assessment (SAUIC; 0.2%). The general SAUC was accomplished for Public Water reclamation (43.4%), seawater supply and drainage (17.5%), dredging sediment (5.5%), installation of port facilities (4.6%) and fishing harbor facilities (2.3%), and others (23.4%). Statements of Environmental Impact Assessment (EIA) were reviewed mainly for construction of port facilities (32.9%), followed by construction of industrial complex, development of tourism and leisure complex, road construction, and development of energy facilities. It would be necessary to strengthen effectiveness of the system, advertisement, and capability of conference and review agency, and to enhance confidence of marine EIA continuously, according to the increase of development projects, and diversity and enlargement of development types.

A Study of Improvement for the Prediction of Groundwater Pollution in Rural Area: Application in Keumsan, Korea (농촌지역 지하수의 오염 예측 방법 개선방안 연구: 충남 금산 지역에의 적용)

  • Cheong, Beom-Keun;Chae, Gi-Tak;Koh, Dong-Chan;Ko, Kyung-Seok;Koo, Min-Ho
    • Journal of Soil and Groundwater Environment
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    • v.13 no.4
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    • pp.40-53
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    • 2008
  • Groundwater pollution prediction methods have been developed to plan the sustainable groundwater usage and protection from potential pollution in many countries. DRASTIC established by US EPA is the most widely used groundwater vulnerability mapping method. However, the DRASTIC showed limitation in predicting the groundwater contamination because the DRASTIC method is designed to embrace only hydrogeologic factors. Therefore, in this study, three different methods were applied to improve a groundwater pollution prediction method: US EPA DRASTIC, Modified-DRASTIC suggested by Panagopoulos et al. (2006), and LSDG (Land use, Soil drainage, Depth to water, Geology) proposed by Rupert (1999). The Modified-DRASTIC is the modified version of the DRASTIC in terms of the rating scales and the weighting coefficients. The rating scales of each factor were calculated by the statistical comparison of nitrate concentrations in each class using the Wilcoxon rank-sum test; while the weighting coefficients were modified by the statistical correlation of each parameter to nitrate concentrations using the Spearman's rho test. The LSDG is a simple rating method using four factors such as Land use, Soil drainage, Depth to water, and Geology. Classes in each factor are compared by the Wilcoxon rank-sum test which gives a different rating to each class if the nitrate concentration in the class is significantly different. A database of nitrate concentrations in groundwaters from 149 wells was built in Keumsan area. Application of three different methods for assessing the groundwater pollution potential resulted that the prediction which was represented by a correlation (r) between each index and nitrate was improved from the EPA DRASTIC (r = 0.058) to the modified rating (r = 0.245), to the modified rating and weights (r = 0.400), and to the LSDG (r = 0.415), respectively. The LSDG seemed appropriate to predict the groundwater pollution in that it contained land use as a factor of the groundwater pollution sources and the rating of each class was defined by a real pollution nitrate concentration.