• Title/Summary/Keyword: annual rate of change

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Analysis of Generalized Extreme Value Distribution to Estimate Storm Sewer Capacity Under Climate Change (기후변화에 따른 하수관거시설의 계획우수량 산정을 위한 일반극치분포 분석)

  • Lee, Hak-Pyo;Ryu, Jae-Na;Yu, Soon-Yu;Park, Kyoo-Hong
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.2
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    • pp.321-329
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    • 2012
  • In this study, statistical analysis under both stationary and non-stationary climate was conducted for rainfall data measured in Seoul. Generalised Extreme Value (GEV) distribution and Gumbel distribution were used for the analysis. Rainfall changes under the non-stationary climate were estimated by applying time variable (t) to location parameter (${\xi}$). Rainfall depths calculated in non-stationary climate increased by 1.1 to 6.2mm and 1.0 to 4.6mm for the GEV distribution and gumbel distribution respectively from those stationary forms. Changes in annual maximum rainfall were estimated with rate of change in the location parameter (${\xi}1{\cdot}t$), and temporal changes of return period were predicted. This was also available for re-evaluating the current sewer design return period. Design criteria of sewer system was newly suggested considering life expectance of the system as well as temporal changes in the return period.

Estimation of Fugitive Emission Factors of HFC-134a from Scrap Cold Drinking Vending Machine at Use- and Disposal-Phase (음료용 폐자동판매기에서의 HFC-134a 사용 및 폐기단계 탈루배출계수 결정에 대한 연구)

  • Lee, Youngphyo;Kim, Eui-Kun;Kim, Seungdo;Byun, Seokho;Kim, Hyerim;Park, Junho;Lee, Dongwon
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.5
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    • pp.350-355
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    • 2013
  • Little information is available for emission pathway even if HFC-134a that is known as one of the major greenhouse gases has been broadly used in Korea. This paper attempts to clarify the emission characteristics of HFC-134a used for refrigerant of cold drinking vending machines (CDVMs) at the use- and disposal-phase. We measured the residual amounts in the scrap CDVMs of 47 by applying commercial recover for refrigerant. The first-order kinetic model was introduced and the emission rate would be proportional to the remaining quantity of refrigerant. The emission factor at the use-phase was determined indirectly to be $6.9{\pm}0.7$ %/yr within a confidence interval of 95%, using information on residual amount and elapsed operation time at the disposal point. Correspondingly, the annual emission rate of HFC-134a per CDVM was determined to be 11.6 g. The average residual rate of HFC-134a in scrap CDVMs was assessed to be $62.5{\pm}2.2%$, leading to a potential emission amount of 144.8 g per scrap CDVM. The chemical compositions of refrigerants from scrap passenger vehicles are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap passenger vehicles could be reused. During the recovering process of refrigerant, the recovered refrigerant was contaminated by compressor lubricant that accounted for about 30% in weight. It is necessary to separate the refrigerant from the recovered material contaminated by lubricant for recycling and reuse the refrigerant.

N-point modified exponential model for household projections in Korea using multi-point register-based census data

  • Saebom Jeon;Tae Yeon Kwon
    • Communications for Statistical Applications and Methods
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    • v.31 no.4
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    • pp.377-391
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    • 2024
  • Accurate household projections are essential for sectors such as housing supply and tax policy planning, given the rapid social changes like declining birthrates, an aging population, and a rise in single-person households that impact household size and type. Korea introduced its first register-based census in 2015, transitioning from five-year general survey-based approach to an annual administrative data-based census. This change in census allows for more frequent and effective capturing the rapid demographic shifts and trends. However, this change in census has caused challenges in future projection by the existing household projection model due to the rapid dynamics. This paper proposes a new household projection method, the N-point Modified Exponential Model (MEM), that accurately reflects register-based census data and mitigates the impact of rapid demographic changes, in three types: the Weighted N-point MEM, the Regression-based N-point MEM, and the Rolling Weighted N+point MEM. Using register-based census data from 2016 to 2020 to forecast household headship rates by age, household size, and household type to 2051, the N-point modified exponential model outperformed the existing model in both long- and short-term forecast accuracy, suggesting its suitability as a future household projection model for Korea.

Statistical Analysis on Application of External Solar Shading Devices (외부 차양장치의 적용실태에 관한 통계적 분석)

  • Kim, Hyo-Jung;Lee, Chul-Sung;Yoon, Jong-Ho
    • KIEAE Journal
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    • v.16 no.5
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    • pp.65-71
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    • 2016
  • Purpose : The solar shading device carries out roles in a reduction of the cooling load and an improvement of the thermal comfort of occupants by adjusting incident solar radiation. In addition, The shading device enhances the visual sensation comfort by controlling the optical properties. In order to improve building performance and comfort of occupancy, interests in application of the shading devices are getting increasing. This study investigated the application and effectiveness of the external shading device design using statistical analysis. The outcome of this paper could be utilized for the realization of status quo and for an estimation of effectiveness of the shading device Method : The period of data gathering was between 2003 and 2014 and total 459 cases of practical building project were investigated. Firstly, this study defined qualification of the shading devices; the shading device should have minimum protruding lengths of 150mm to outside and have the function of shading control. This paper investigated application rate of the shading device in real project, regional rate of application, annual change of application, materials and types. Result : The statistical analysis showed that the application rate of shading devices was 25.7% in total 459 building design projects. The application rate in central and southern region was 25.3% and 27.0% respectively. Meanwhile, Jeju region showed 22.2%, which was the lowest rate although this area needs more shading devices. The application number of the shading device was the smallest in 2007, but the rate gradually increased after that. The applications was the largest in 2014 due to growing interest of the shading devices in the building.

effect of Cattle Compost and NPK Application on Growth and Dry Matter Accumulation of Selected Forage Crops on Neqly Reclaimed Uplands (신개간지에서 구비 및 삼요소시용이 청예사료작물의 생육 및 건물축적에 미치는 영향)

  • 한민수;박종선
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.11 no.2
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    • pp.108-115
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    • 1991
  • A field experiment was conducted to evaluate the effects of cattle compost application on the change of soil physical properties and their relationship to yield performance of selected main forage crops. Maize(CV. Suweon 19) and sorghum hybrids(CV. Pioneer 9'31) as a summer crops and winter rye were grown on newly reclaimed red yellow soils(Fine loamy, Typic Hapludults) under different application rate of cattle compost associated with chemical NPK fertilization, from Oct. 1986 to Sept. 1989. Experimental field was laid down as a split plots design with four replications. The results obtained are summarized as follows: 1. Cattle compost application reclaimed soil physical propeties, such as formation of granular structure and water holding capacity, and it result in a great increase of plant growth and the rate of dry matter accumulation. 2. While cattle compost treatment reduced the portion of soild phase of the three phase constituents of soils, it increased the portion of air phase and liquid phase comparatively. 3. Organic matter, N, P, K, and mineral content in soil were markedly increased in the plot treated with compost. 4. Cattle compost application increased fodder production both in maize-rye and sorghum hybrids-rye cultivation. Annual dry matter yield of maize-rye cropping was 2183(NI'K only), 2425(NPK+compvst 3000 kg) and 2800kg/lOa(NPK + compost 6000kg/10a).

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Spatiotemporal evolution and influencing factors of ecosystem service value in the Sanjiangyuan nature reserve nature reserve

  • Liu, Hao;Shu, Chang;Sun, Lihui
    • Advances in nano research
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    • v.12 no.3
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    • pp.319-336
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    • 2022
  • Evaluating the temporal and spatial changes in the ecosystem service value (ESV) of the Sanjiangyuan Nature Reserve is important for understanding the impact of human activities on natural ecosystem and guiding ecosystem restoration and environmental pollution control. In this study, remotely sensed land-cover data and the equivalent factor method were used to analyze the spatiotemporal evolution characteristics of the ESV in Sanjiangyuan Nature Reserve from 1992 to 2015, and regression analysis was employed to determine the factors driving changes in the ESV. The results show that grassland was the main type of ecosystem in the study area, and the transformation of grassland into bare areas was the primary change in land cover. Additionally, the ESV in the study area first decreased and then increased, with an annual growth rate of 0.69%. The ESV mainly increased in the north of the Yellow River's source area, and mainly decreased in the northwest of the Yangtze River's source area. Finally, the gross output value of agriculture, urbanization rate and proportion of secondary industry were found to be the main factors driving the ESV in the study area.

The Effect of Soil Permeability and Pumping Rate on Performance of Two-well Geothermal Heat Pump System (지반 투수계수와 양수량 조건이 복수정 지열 히트펌프 시스템의 성능에 미치는 영향)

  • Cho, Jeong-Heum;Nam, Yujin
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.11 no.4
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    • pp.28-34
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    • 2015
  • The groundwater heat pump (GWHP) systems have great potential for heating-cooling system which use annual constant groundwater temperature for heat source. Generally, the performance of GWHP system significantly depends on the geological and hydraulic properties such as hydraulic conductivity, thermal conductivity, soil condition so on. Therefore, in order to use GWHP systems efficiently, it is necessary to analyze the effect of design factors on the system performance. However, there are a few researches on the optimum design method for the open-loop geothermal system. In this research, the design factor in the open-loop geothermal system was analyzed quantitatively for the optimal design method by using numerical simulation. As a result, it was found that the temperature change of heat source depends on the design factor.

The Transition of Production, Consumption and Price of Non-ferrous Metals (비철금속(非鐵金屬)의 생산(生産), 소비(消費), 시세(時勢)의 추이(推移))

  • Moon, W.J.
    • Economic and Environmental Geology
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    • v.2 no.3
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    • pp.1-25
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    • 1969
  • In considering the mining industry, it is necessary to study the production, consumption and price of ore and metals in every country of the world in order to determine the trend of the industry in the present and for the future. This study is necessary especially for exporting domestically produced are which is in excess of domestic consumption and for importing are, or metal where local production does not meet domestic demand. It will be treated of Au, Ag, Cu, Pb, Zn, W, Mo, which are the most important non-ferrous metals, and which greatly affect the mining industry of Korea. The presentation will concern itself only with the free world. About 1, 200 ton of gold are produced annually with little fluctiation in recent years. Most of the gold produced is consumed by advanced countries for industrial uses as well as for producing precious objects. The U.S.A. expends yearly about four times its domestic production and Japan about three times its domestic production for industry and arts. Because of the instability of the currency of the U.S.A., England and France, recently, the price of gold has been $ 41-42 per ounce, whereas the official price is $35.00 per ounce. It will be expected that the official price will be raised in the near future. As for silver, about 6,500 tons are produced annually with no special fluctuation change in recent years. However, the annual consumption is about 14,000 ton, so the supply and demand is extremely unbalanced. The shortage is made up by the sale of the U.S. treasury's reserve stock and the reclaiminig of silver from coins and other scrap. As the Treasury'S reserves will be exhausted in a year or two, the price of silver which is $1. 64 per ounce, will go up drastically in about a year. As for copper, 5,257,000 ton's were mined in 1966. It's production is being increased about 5% annually. However, consumption exceeds production by about 100,000 ton a year. The recent Foreign refinery copper price in the U.S.A is $ 60 per pound. The supply of copper being insufficient to meet international demands, the price will go up and with no prospect of being lowered in the near future even with the slight annual increase in production. About 2,100,000 to 2,200,000 tons of lead are produced annually. Consumption exceeds production by about 50,000-60,000 tons annually. The current price of lead in New York is $ 155 per pound. As the supply of lead is internationally stable, It will be believed that there will be no significant change in its price in the near future. In 1967, 3,926,000 tons of Zinc were produced. There is annual increase of 4-7% in production. The annual consumption exceeds production by 100,000 to 200,000 tons. The current zinc price in the St. Louis market inthe U.S.A. is $ 145 per pound. Even though its supply is stable and sufficient world wide, the consumption rate will increase at a faster pace than before; hence, the price will slowly go up. Tungsten mines yield about 11,000 tons a year. Its production has been relatively constant in the past few years. The amount of its consumption increases slowly world wide, but in the free world· there has been a slight annual decrease. However, since Red China has not been exporting their tungsten to other countries for several months, the price on the London market of S.T.U. of $Wo_3$ has increased to $ 44~46. Should Red China begin to export actively again the price will drop to $ 40~42. In 1967, 56,000 tons of Molybdenum were produced. Production exceeds consumption by 200,000 -30,000 tons annually. The current price in the U.S.A. is $ 1.72 per Mo pound. Since the rate of production in the U.S.A. is on the increase with large amounts of ore reserve, the price of molubdenum should not go up.

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Association between Scrub Typhus Outbreaks and Meteorological Factors in Jeollabuk-do Province (전북지역 쯔쯔가무시증 발생과 기후요소의 상호 관련성)

  • Kang, Gong-Unn;Ma, Chang-Jin;Oh, Gyung-Jae
    • Journal of Environmental Health Sciences
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    • v.42 no.1
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    • pp.41-52
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    • 2016
  • Objectives: Scrub typhus is one of the most prevalent vector-borne diseases. It is caused by Orientia tsutsugamushi, which is transmitted when people are bitten by infected chigger mites. This study aims at quantifying the association between the incidence of scrub typhus and meteorological factors in Jeollabuk-do Province over the period 2001-2015. Methods: Reported cases of scrub typhus were collected from the website of the Disease Web Statistical System supported by the Korea Centers for Disease Control and Prevention (KCDC). Simultaneous meteorological data, including temperature, rainfall, relative humidity, and sunshine duration were collected from the website of the National Climate Data Service System by the Korea Meteorological Administration. Correlation and regression analyses were applied to identify the association between the incidence of scrub typhus and meteorological factors. Results: The general epidemiological characteristics of scrub typhus in Jeollabuk-do Province were similar to those nationwide for sex, age, and geographical distribution. However, the annual incidence rate (i.e., cases per 100,000) of scrub typhus in Jeollabuk-do Province was approximately four times higher than all Korea's 0.9. The number of total cases was the highest proportion at 13.3% in Jeonbuk compared to other regions in Korea. The results of correlation analysis showed that there were significant correlations between annual cases of scrub typhus and monthly data for meteorological factors such as temperature and relative humidity in late spring and summer, especially in the case of temperature in May and June. The results of regression analysis showed that determining factors in the regression equation explaining the incidence of scrub typhus reached 46.2% and 43.5% in May and June. Using the regression equation, each 1oC rise in the monthly mean temperature in May or June may lead to an increase of 38 patients with scrub typhus compared to the annual mean of incidence cases in Jeollabuk-do Province. Conclusion: The result of our novel attempts provided rational evidence that meteorological factors are associated with the occurrence of scrub typhus in Jeollabuk-do. It should therefore be necessary to observe the trends and predict patterns of scrub typhus transmission in relation to global-scale climate change. Also, action is urgently needed in all areas, especially critical regions, toward taking steps to come up with preventive measures against scrub typhus transmission.

Estimates of the Water Cycle and River Discharge Change over the Global Land at the End of 21st Century Based on RCP Scenarios of HadGEM2-AO Climate Model (기후모델(HadGEM2-AO)의 대표농도경로(RCP) 시나리오에 따른 21세기 말 육지 물순환 및 대륙별 하천유출량 변화 추정)

  • Kim, Moon-Hyun;Kang, Hyun-Suk;Lee, Johan;Baek, Hee-Jeong;Cho, ChunHo
    • Atmosphere
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    • v.23 no.4
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    • pp.425-441
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    • 2013
  • This study investigates the projections of water cycle, budget and river discharge over land in the world at the end of twenty-first century simulated by atmosphere-ocean climate model of Hadley Centre (HadGEM2-AO) and total runoff integrating pathways (TRIP) based on the RCP scenario. Firstly, to validate the HadGEM2-AO hydrology, the surface water states were evaluated for the present period using precipitation, evaporation, runoff and river discharge. Although this model underestimates the annual precipitation about 0.4 mm $mon^{-1}$, evaporation 3.7 mm $mon^{-1}$, total runoff 1.6 mm $mon^{-1}$ and river discharge 8.6% than observation and reanalysis data, it has good water balance in terms of inflow and outflow at surface. In other words, it indicates the -0.3 mm $mon^{-1}$ of water storage (P-E-R) compared with ERA40 showing -2.4 mm $mon^{-1}$ for the present hydrological climate. At the end of the twenty-first century, annual mean precipitation may decrease in heavy rainfall region, such as northern part of South America, central Africa and eastern of North America, but for increase over the Tropical Western Pacific and East Asian region. Also it can generally increase in high latitudes inland of the Northern Hemisphere. Spatial patterns of annual evaporation and runoff are similar to that of precipitation. And river discharge tends to increase over all continents except for South America including Amazon Basin, due to increased runoff. Overall, HadGEM2-AO prospects that water budget for the future will globally have negative signal (-8.0~-0.3% of change rate) in all RCP scenarios indicating drier phase than the present climate over land.