• Title/Summary/Keyword: Long-Term Trend

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Long-gap Filling Method for the Coastal Monitoring Data (해양모니터링 자료의 장기결측 보충 기법)

  • Cho, Hong-Yeon;Lee, Gi-Seop;Lee, Uk-Jae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.33 no.6
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    • pp.333-344
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    • 2021
  • Technique for the long-gap filling that occur frequently in ocean monitoring data is developed. The method estimates the unknown values of the long-gap by the summation of the estimated trend and selected residual components of the given missing intervals. The method was used to impute the data of the long-term missing interval of about 1 month, such as temperature and water temperature of the Ulleungdo ocean buoy data. The imputed data showed differences depending on the monitoring parameters, but it was found that the variation pattern was appropriately reproduced. Although this method causes bias and variance errors due to trend and residual components estimation, it was found that the bias error of statistical measure estimation due to long-term missing is greatly reduced. The mean, and the 90% confidence intervals of the gap-filling model's RMS errors are 0.93 and 0.35~1.95, respectively.

Long-term Changes and Variational Characteristics of Water Quality in the Cheonsu Bay of Yellow Sea, Korea (천수만의 수질환경특성과 장기변동)

  • Park, Soung-Yun;Park, Gyung-Soo;Kim, Hyung-Chul;Kim, Pyoung-Joong;Kim, Jeon-Poong;Park, Jung-Hyeon;Kim, Sug-Yang
    • Journal of Environmental Science International
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    • v.15 no.5
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    • pp.447-459
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    • 2006
  • Long-term trends and distribution patterns of water quality were investigated in the Cheonsu Bay of Korea from 1983 to 2004. Water samples were collected at 4 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns were not clear between stations but the seasonal variations were distinctive except COD, SS and nitrate. Twenty two year long-term trend analysis by PCA revealed the significant changes in water quality in the study area. Water quality during 1980's and early 1990's showed high SS, low nutrients and low COD which increased during the mid and late 1990's and early 2000's. Overall water duality in the Cheonsu Bay indicated the increase in nutrients and COD concentration.

Trends in Home-visit Nursing Care by Agencies' Characteristics under the National Long-term Care Insurance System (노인장기요양보험의 방문간호 제공기관 특성별 서비스 제공 추이)

  • Lee, Jung Suk;Hwang, Rah Il;Han, Eun Jeong
    • Research in Community and Public Health Nursing
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    • v.23 no.4
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    • pp.415-426
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    • 2012
  • Purpose: This study aimed to investigate trends in home-visit nursing care by agencies' characteristics under the national long-term care insurance system. Methods: Cochran-Mantel-Haenzel tests were conducted, using data drawn from the nationwide long-term care insurance claim database of the Korean National Health Insurance Corporation from 2009 to 2011. Results: The number of home-visit nursing care agencies has decreased continuously since 2009. There were also similar trends in the total amount of service provided by home-visit nursing care agencies, the number of recipients, the number of employees, and payments. This study showed that there were statistically significant differences in the trends in home-visit nursing care by agencies' characteristics. Despite the overall downward trend, there were some increases in the percentage of home-visit nursing care provided by agencies which were established by individuals, located in large cities, and which combined home-visit care with home-visit bathing. Conclusion: Home-visit nursing care agencies are responsible for providing community-based healthcare services. For past three years, however, they have not been utilized to their full potential. Understanding the trends in home-visit nursing care by agencies' characteristics is important to develop utilization strategies for home-visit nursing care.

Long-Term Slope Stability Considering Strength Degradation of Soil (지반의 열화에 따른 사면의 장기 안정성 검토)

  • Jaemo Kang;Hoki Ban
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.11
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    • pp.25-31
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    • 2024
  • The strength of ground tends to weaken as time goes, and experimental observation and measured data indicate that this reduction in strength follows an exponential degradation trend. Therefore, this study presents a degradation model in which the ground strength parameters degraded according the history of time. Using the proposed model, the long-term stability of slope is predicted through numerical analysis, and the results are presented. Based on the these results, it is possible to predict the long-term behavior of slope and provide a basis for determining when the maintenance or reinforcement might be necessary.

Multimodal therapy for locally advanced prostate cancer: the roles of radiotherapy, androgen deprivation therapy, and their combination

  • Lee, Sung Uk;Cho, Kwan Ho
    • Radiation Oncology Journal
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    • v.35 no.3
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    • pp.189-197
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    • 2017
  • Locally advanced prostate cancer (LAPC) is defined as histologically proven T3-4 prostatic adenocarcinoma. In this review, we define the individual roles of radiotherapy (RT), short-term (ST-) and long-term (LT-) androgen deprivation therapy (ADT), and their combination in multimodal therapy for LAPC. Despite limitations in comparing the clinical outcomes among published papers, in the present study, a trend of 10-year clinical outcomes was roughly estimated by calculating the average rates weighted by the cohort number. With RT alone, the following rates were estimated: 87% biochemical failure, 34% local failure (LF), 48% distant metastasis (DM), 38% overall survival (OS), and 27% disease-specific mortality (DSM). Those associated with ADT alone were 74% BCF, 54% OS, and 25% DSM, which appeared to be better than those of RT alone. The addition of ADT to RT produced a notable local and systemic effect, regardless of ST- or LT-ADT. The LF rate decreased from 34% with RT alone to 21% with ST-ADT and further to 15% with LT-ADT. The DM and DSM rates also showed a similar trend among RT alone, RT+ST-ADT, and RT+LT-ADT. The combination of RT+LT-ADT resulted in the best long-term clinical outcomes, indicating that both RT and ADT are important parts of multimodal therapy.

The Variations of Stratospheric Ozone over the Korean Peninsula 1985~2009 (한반도 상공의 오존층 변화 1985~2009)

  • Park, Sang Seo;Kim, Jhoon;Cho, Nayeong;Lee, Yun Gon;Cho, Hi Ku
    • Atmosphere
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    • v.21 no.4
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    • pp.349-359
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    • 2011
  • The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

Selection of Climate Indices for Nonstationary Frequency Analysis and Estimation of Rainfall Quantile (비정상성 빈도해석을 위한 기상인자 선정 및 확률강우량 산정)

  • Jung, Tae-Ho;Kim, Hanbeen;Kim, Hyeonsik;Heo, Jun-Haeng
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.1
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    • pp.165-174
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    • 2019
  • As a nonstationarity is observed in hydrological data, various studies on nonstationary frequency analysis for hydraulic structure design have been actively conducted. Although the inherent diversity in the atmosphere-ocean system is known to be related to the nonstationary phenomena, a nonstationary frequency analysis is generally performed based on the linear trend. In this study, a nonstationary frequency analysis was performed using climate indices as covariates to consider the climate variability and the long-term trend of the extreme rainfall. For 11 weather stations where the trend was detected, the long-term trend within the annual maximum rainfall data was extracted using the ensemble empirical mode decomposition. Then the correlation between the extracted data and various climate indices was analyzed. As a result, autumn-averaged AMM, autumn-averaged AMO, and summer-averaged NINO4 in the previous year significantly influenced the long-term trend of the annual maximum rainfall data at almost all stations. The selected seasonal climate indices were applied to the generalized extreme value (GEV) model and the best model was selected using the AIC. Using the model diagnosis for the selected model and the nonstationary GEV model with the linear trend, we identified that the selected model could compensate the underestimation of the rainfall quantiles.

The Long-term Variation Patterns of Atmospheric Mercury in Seoul, Korea from 1997 to 2002 (서울시 대기 중 수은농도의 장기변동 특성 1997~2002)

  • 김민영;김기현
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.2
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    • pp.179-189
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    • 2003
  • The concentration of gaseous elemental mercury (Hg) was measured concurrently with relevant environmental parameters from Yang-Jae monitoring station in Seoul during Sept. 1997 to June 2002. Although data collection was disrupted for certain periods, the grand mean concentration of Hg for this five year period was found at 5.32 $\pm$ 3.53 ng m$^{-3}$ (N = 27,170). Because of short resolution of data acquisition, we were able to examine the temporal variability of Hg at varying time scale. The diurnal variability of Hg, when investigated for each of those five years, indicated consistently the dominance of nighttime over daytime. If examined at seasonal scale, Hg level was systematically higher during winter/spring than summer/fall period. The results of this short-term variability were best explained by the combined effects of such factors as meteorological conditions (formation of inversion layer and seasonal changes) and anthropogenic source processes. However, examination of long-term variation Pattern was much more complicated to explain. Thus, extension of our study is needed to diagnose the future direction in long-term trend of Hg behavior.

Future Change Using the CMIP5 MME and Best Models: II. The Thermodynamic and Dynamic Analysis on Near and Long-Term Future Climate Change over East Asia (CMIP5 MME와 Best 모델의 비교를 통해 살펴본 미래전망: II. 동아시아 단·장기 미래기후전망에 대한 열역학적 및 역학적 분석)

  • Kim, Byeong-Hee;Moon, Hyejin;Ha, Kyung-Ja
    • Atmosphere
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    • v.25 no.2
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    • pp.249-260
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    • 2015
  • The changes in thermodynamic and dynamic aspects on near (2025~2049) and long-term (2075~2099) future climate changes between the historical run (1979~2005) and the Representative Concentration Pathway (RCP) 4.5 run with 20 coupled models which employed in the phase five of Coupled Model Inter-comparison Project (CMIP5) over East Asia (EA) and the Korean Peninsula are investigated as an extended study for Moon et al. (2014) study noted that the 20 models' multi-model ensemble (MME) and best five models' multi-model ensemble (B5MME) have a different increasing trend of precipitation during the boreal winter and summer, in spite of a similar increasing trend of surface air temperature, especially over the Korean Peninsula. Comparing the MME and B5MME, the dynamic factor (the convergence of mean moisture by anomalous wind) and the thermodynamic factor (the convergence of anomalous moisture by mean wind) in terms of moisture flux convergence are analyzed. As a result, the dynamic factor causes the lower increasing trend of precipitation in B5MME than the MME during the boreal winter and summer over EA. However, over the Korean Peninsula, the dynamic factor causes the lower increasing trend of precipitation in B5MME than the MME during the boreal winter, whereas the thermodynamic factor causes the higher increasing trend of precipitation in B5MME than the MME during the boreal summer. Therefore, it can be noted that the difference between MME and B5MME on the change in precipitation is affected by dynamic (thermodynamic) factor during the boreal winter (summer) over the Korean Peninsula.

Applications of Gaussian Process Regression to Groundwater Quality Data (가우시안 프로세스 회귀분석을 이용한 지하수 수질자료의 해석)

  • Koo, Min-Ho;Park, Eungyu;Jeong, Jina;Lee, Heonmin;Kim, Hyo Geon;Kwon, Mijin;Kim, Yongsung;Nam, Sungwoo;Ko, Jun Young;Choi, Jung Hoon;Kim, Deog-Geun;Jo, Si-Beom
    • Journal of Soil and Groundwater Environment
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    • v.21 no.6
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    • pp.67-79
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    • 2016
  • Gaussian process regression (GPR) is proposed as a tool of long-term groundwater quality predictions. The major advantage of GPR is that both prediction and the prediction related uncertainty are provided simultaneously. To demonstrate the applicability of the proposed tool, GPR and a conventional non-parametric trend analysis tool are comparatively applied to synthetic examples. From the application, it has been found that GPR shows better performance compared to the conventional method, especially when the groundwater quality data shows typical non-linear trend. The GPR model is further employed to the long-term groundwater quality predictions based on the data from two domestically operated groundwater monitoring stations. From the applications, it has been shown that the model can make reasonable predictions for the majority of the linear trend cases with a few exceptions of severely non-Gaussian data. Furthermore, for the data shows non-linear trend, GPR with mean of second order equation is successfully applied.