• 제목/요약/키워드: Bias correlation

검색결과 344건 처리시간 0.028초

WRF, MM5, RSM 모형에서 모의한 2004년 7월 11-18일의 동아시아 몬순의 비교 (Intercomparison of the East-Asian Summer Monsoon on 11-18 July 2004, simulated by WRF, MM5, and RSM models)

  • 함수련;박선주;방철한;정병주;홍성유
    • 대기
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    • 제15권2호
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    • pp.91-99
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    • 2005
  • This study compares the summer monsoon circulations during a heavy rainfall period over the Korean peninsular from 11 to 18 July 2004, simulated by three widely used regional models; WRF, MM5, and RSM. An identical model setup is carried out for all the experiments, except for the physical option differences in the RSM. The three models with a nominal resolution of about 50 km over Korea are nested by NCEP-DOE reanalysis data. Another RSM experiment with the same cumulus parameterization scheme as in the WRF and MM5 is designed to investigate the importance of the representation of subgrid-scale parameterized convection in reproducing monsoonal circulations in East Asia. All thee models are found to be capable of reproducing the general distribution of monsoonal precipitation, extending northeastward from south China across the Korean peninsula, to northern Japan. The results from the WRF and MM5 are similar in terms of accumulated precipitation, but a slightly better performance in the WRF than in the MM5. The RSM improves the bias for precipitation as compared to those from the WRF and MM5, but the pattern correlation is degraded due to overestimation of precipitation in northern China. In the comparison of simulated synoptic scale features, the RSM is found to reproduce the large-scale features well compared to the results from the MM5 and WRF. On the other hand, the simulated precipitation from the RSM with the convection scheme used in the MM5 and WRF is closer to that from the WRF and MM5 simulations, indicating the significant dependency of simulated precipitation in East Asia on the cumulus parameterization scheme.

GloSea5 모형의 6개월 장기 기후 예측성 검증 (Assessment of 6-Month Lead Prediction Skill of the GloSea5 Hindcast Experiment)

  • 정명일;손석우;최정;강현석
    • 대기
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    • 제25권2호
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    • pp.323-337
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    • 2015
  • This study explores the 6-month lead prediction skill of several climate indices that influence on East Asian climate in the GloSea5 hindcast experiment. Such indices include Nino3.4, Indian Ocean Diploe (IOD), Arctic Oscillation (AO), various summer and winter Asian monsoon indices. The model's prediction skill of these indices is evaluated by computing the anomaly correlation coefficient (ACC) and mean squared skill score (MSSS) for ensemble mean values over the period of 1996~2009. In general, climate indices that have low seasonal variability are predicted well. For example, in terms of ACC, Nino3.4 index is predicted well at least 6 months in advance. The IOD index is also well predicted in late summer and autumn. This contrasts with the prediction skill of AO index which shows essentially no skill beyond a few months except in February and August. Both summer and winter Asian monsoon indices are also poorly predicted. An exception is the Western North Pacific Monsoon (WNPM) index that exhibits a prediction skill up to 4- to 6-month lead time. However, when MSSS is considered, most climate indices, except Nino3.4 index, show a negligible prediction skill, indicating that conditional bias is significant in the model. These results are only weakly sensitive to the number of ensemble members.

동아시아 지역의 AERONET 관측자료를 이용한 천리안 위성 기상탑재체의 에어로솔 광학두께 산출물의 검증 (Validation of COMS/MI Aerosol Optical Depth Products Using Aerosol Robotic Network (AERONET) Observations Over East Asia)

  • 이권호
    • 대한원격탐사학회지
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    • 제34권3호
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    • pp.507-517
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    • 2018
  • 천리안 위성(Communication, Ocean and Meteorological Satellite, COMS)의 에어로솔 광학두께(Aerosol Optical Depth; AOD) 산출물의 검증을 위하여, 동아시아 지역을 대상으로 2011년 1월부터 2014년 7월까지 산출자료와 134개의 지상관측 Aerosol Robotic Network(AERONET) AOD와 비교 분석하였다. 시공간 일치법을 사용하여 천리안 위성 AOD와 AERONET 전체 관측 지점의 AOD의 비교결과는 약한 상관관계(R=0.297)와 함께 천리안 AOD가 과대평가된 결과를 나타내었다. 그러나, AERONET 관측지점별 비교 결과는 각 지점별로 상이한 결과를 나타내었으며, 최소 상관계수 R=0.026(AOE_Baotou 지점) 과 최대 상관계수 R=0.905(DRAGON_Anmyeon 지점)을 보였다. 천리안 AOD와 AERONET AOD의 편차와 입자 유효반경, 수증기, 지표반사도, 태양천정각과의 비교결과, 천리안 AOD 산출물에 대한 계통적 오차가 발견되지 않았다. 그러나 한반도 인근지역의 한정된 지역을 대상으로 하면 천리안 AOD와 AERONET AOD의 유사성이 나타나므로, 지역적인 한계가 있음을 발견하였다. 마지막으로, 본 연구 결과는 COMS AOD 산출 알고리즘의 개선에 도움을 줄 수 있을 것이며, 따라서 개선된 비교검증 결과를 얻을 수 있을 것이다.

중규모 수치 모델 자료를 이용한 2007년 여름철 한반도 인지온도 예보와 검증 (Forecast and verification of perceived temperature using a mesoscale model over the Korean Peninsula during 2007 summer)

  • 변재영;김지영;최병철;최영진
    • 대기
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    • 제18권3호
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    • pp.237-248
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    • 2008
  • A thermal index which considers metabolic heat generation of human body is proposed for operational forecasting. The new thermal index, Perceived Temperature (PT), is forecasted using Weather Research and Forecasting (WRF) mesoscale model and validated. Forecasted PT shows the characteristics of diurnal variation and topographic and latitudinal effect. Statistical skill scores such as correlation, bias, and RMSE are employed for objective verification of PT and input meteorological variables which are used for calculating PT. Verification result indicates that the accuracy of air temperature and wind forecast is higher in the initial forecast time, while relative humidity is improved as the forecast time increases. The forecasted PT during 2007 summer is lower than PT calculated by observation data. The predicted PT has a minimum Root-Mean-Square-Error (RMSE) of $7-8^{\circ}C$ at 9-18 hour forecast. Spatial distribution of PT shows that it is overestimated in western region, while PT in middle-eastern region is underestimated due to strong wind and low temperature forecast. Underestimation of wind speed and overestimation of relative humidity have caused higher PT than observation in southern region. The predicted PT from the mesoscale model gives appropriate information as a thermal index forecast. This study suggests that forecasted PT is applicable to the prediction of health warning based on the relationship between PT and mortality.

부유성 유공충의 유생은 고해양/고기후의 연구에 영향을 미치는가\ulcorner : 1년간의 퇴적물트랩 관찰로부터 (Do Planktonic Foraminifera Juveniles Bias the Paleoceanographic/Paleoclimatic History Interpretation\ulcorner : Short Report of Year-long Trap Result)

  • Im Chul Shin;Byong-Kwon Park;Hi-Il Yi
    • 한국제4기학회지
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    • 제13권1호
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    • pp.91-98
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    • 1999
  • 부유성 유공충의 상대적인 양이 고기후 및 고해양환경의 해석에 미치는 영향을 1년 동안 관찰한 퇴적물 포집장치에 함유된 유공충의 연구로 행하여졌다. 본 연구는 저자들이 알고 있는 한 처음으로 행해진 것이다. 총 부유성 유공충의 수, 고기후의 지시자로 사용되는 부유성 유공충 G. bulliodes와 N. dutertrei)의 상대적인 양, 수온, 염도 등은 부유성 유공충 유생의 상대적인 양과 통계적으로 의미 있는 상관관계를 보이지 않는다. 하지만 부유성 유공충 유생의 상대적인 양은 종다양성지수(종 풍성도, 샤논-와이너 지수, 균등도)와 상관관계를 보인다. 이러한 결과는 유생의 양은 종의 상대적인 양에는 영향을 미치지 않으나 종다양성에는 영향을 미침을 의미한다. 따라서 퇴적물 포집장치에서 일년간 관찰한 결과에 의하면 부유성 유공충의 유생을 count 시 제외했을 때 종다양성 지수를 이용한 고기후/고환경해석시 주의 가 요망된다.

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AIRS를 이용한 대기 수증기 관측 (Observation of Atmospheric Water Vapors Using AIRS)

  • 하지현;김두식;박관동;원지혜
    • Journal of Astronomy and Space Sciences
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    • 제26권4호
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    • pp.547-554
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    • 2009
  • AIRS는 미국 NASA의 지구관측위성인 Aqua에 탑재되어 있으며, 적외선 채널을 이용하여 지구 대기의 수증기량을 관측한다. 이 논문에서는 AIRS 적외선 관측데이터를 이용하여 인천에 소재한 GPS 상시관측소 상공에 분포하는 가강수량을 추출하고, 이를 GPS 추정치와 비교하였다. 그 결과 AIRS에서 관측된 가강수량과 GPS 가강수량은 거의 비슷한 경향을 보였으며, GPS 가강수량을 기준으로 편향 0.3cm, RMSE 0.7cm의 정확도를 달성하였다. GPS 가강수량과 AIRS 가강수량의 상관관계 분석 결과 0.89의 높은 상관계수를 보여 AIRS 가강수량이 지역적 특성을 비교적 잘 반영함을 알 수 있었다.

Accuracy of predictive equations for resting metabolic rate in Korean athletic and non-athletic adolescents

  • Kim, Jae-Hee;Kim, Myung-Hee;Kim, Gwi-Sun;Park, Ji-Sun;Kim, Eun-Kyung
    • Nutrition Research and Practice
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    • 제9권4호
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    • pp.370-378
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    • 2015
  • BACKGROUND/OBJECTIVES: Athletes generally desire changes in body composition in order to enhance their athletic performance. Often, athletes will practice chronic energy restrictions to attain body composition changes, altering their energy needs. Prediction of resting metabolic rates (RMR) is important in helping to determine an athlete's energy expenditure. This study compared measured RMR of athletic and non-athletic adolescents with predicted RMR from commonly used prediction equations to identify the most accurate equation applicable for adolescent athletes. SUBJECTS/METHODS: A total of 50 athletes (mean age of $16.6{\pm}1.0years$, 30 males and 20 females) and 50 non-athletes (mean age of $16.5{\pm}0.5years$, 30 males and 20 females) were enrolled in the study. The RMR of subjects was measured using indirect calorimetry. The accuracy of 11 RMR prediction equations was evaluated for bias, Pearson's correlation coefficient, and Bland-Altman analysis. RESULTS: Until more accurate prediction equations are developed, our findings recommend using the formulas by Cunningham (-29.8 kcal/day, limits of agreement -318.7 and +259.1 kcal/day) and Park (-0.842 kcal/day, limits of agreement -198.9 and +196.9 kcal/day) for prediction of RMR when studying male adolescent athletes. Among the new prediction formulas reviewed, the formula included in the fat-free mass as a variable [$RMR=730.4+15{\times}fat-free\;mass$] is paramount when examining athletes. CONCLUSIONS: The RMR prediction equation developed in this study is better in assessing the resting metabolic rate of Korean athletic adolescents.

역정규 손실함수를 이용한 기대손실 능력지수의 개발 (Development of Expected Loss Capability Index Using Reflected Normal Loss Function)

  • 전동진;정영배
    • 산업경영시스템학회지
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    • 제40권1호
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    • pp.41-49
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    • 2017
  • Process quality control, which prevents problems and risks that may occur in products and processes, has been recognized as an important issue, and SPC techniques have been used for this purpose. Process Capability Index (PCI) is useful Statistical Process Control (SPC) tool that is measure of process diagnostic and assessment tools widely use in industrial field. It has advantage of easy to calculate and easy to use in the field. $C_p$ and $C_{pk}$ are traditional PCIs. These traditional $C_p$ and $C_{pk}$ were used only as a measure of process capability, taking into account the quality variance or the bias of the process mean. These are not given information about the characteristic value does not match the target value of the process and this has the disadvantage that it is difficult to assess the economic losses that may arise in the enterprise. Studies of this process capability index by many scholars actively for supplement of its disadvantage. These studies to evaluate the capability of situation of various field has presented a new process capability index. $C_{pm}$ is considers both the process variation and the process deviation from target value. And $C_{pm}{^+}$ is considers economic loss for the process deviation from target value. In this paper we developed an improved Expected Loss Capability Index using Reflected Normal Loss Function of Spring. This has the advantage that it is easy to realistically reflect the loss when the specification is asymmetric around the target value. And check the correlation between existing traditional process capability index ($C_{pk}$) and new one. Finally, we propose the criteria for classification about developed process capability index.

Metformin Association with Lower Prostate Cancer Recurrence in Type 2 Diabetes: a Systematic Review and Meta-analysis

  • Hwang, In Cheol;Park, Sang Min;Shin, Doosup;Ahn, Hong Yup;Rieken, Malte;Shariat, Shahrokh F.
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권2호
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    • pp.595-600
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    • 2015
  • Background: Accumulating evidence suggests that metformin possesses anticarcinogenic properties, and its use is associated with favorable outcomes in several cancers. However, it remains unclear whether metformin influences prognosis in prostate cancer (PCa) with concurrent type 2 diabetes (T2D). Materials and Methods: We searched PubMed, EMBASE, and the Cochrane Library from database inception to April 16, 2014 without language restrictions to identify studies investigating the effect of metformin treatment on outcomes of PCa with concurrent T2D. We conducted a meta-analysis to quantify the risk of recurrence, progression, cancer-specific mortality, and all-cause mortality. Summary relative risks (RRs) with corresponding 95% confidence intervals (CIs) were calculated. Publication bias was assessed by Begg's rank correlation test. Results: A total of eight studies fulfilled the eligibility criteria. We found that diabetic PCa patients who did not use metformin were at increased risk of cancer recurrence (RR, 1.20; 95%CI, 1.00-1.44), compared with those who used metformin. A similar trend was observed for other outcomes, but their relationships did not reach statistical significance. Funnel plot asymmetry was not observed among studies reporting recurrence (p=0.086). Conclusions: Our results suggest that metformin may improve outcomes in PCa patients with concurrent T2D. Well-designed large studies and collaborative basic research are warranted.

니트 플레어스커트의 제작 방법에 따른 외관 평가 - 봉제형과 무 봉제형 - (A Study on the Knit Flare Skirts for Making Method through Sensory Test - Cut & Sew and Seamless Making Method -)

  • 기희숙;김영주;서정권;류경옥;서미아
    • 복식문화연구
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    • 제18권3호
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    • pp.465-475
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    • 2010
  • For this study, 18 kinds of cut and sew or seamless knitted test garment were made. Samples differed from each other by skirt angles($90^{\circ}$, $180^{\circ}$), gauges(7G, 12G, 15G), and grain directions(bias direction, wale direction, and radial direction). After measuring the mechanical properties of various gauges on the seamless knitting machine, I compared shape of the knitted flare skirt through subjective evaluation on appearances. The data analysis methods used in this study were descriptive statistics, one-way ANOVA, Duncan-test, correlation analysis, and regression analysis. The subjective evaluation on appearances of knitted flare skirts showed the following: In case of $90^{\circ}$ skirt, the seamless skirt showed a much higher score in every gauge expect that of the cut and sew 12G, and silhouette of 15G wale direction. In case of the $180^{\circ}$ skirt, the seamless type showed a much higher score in every item over the cut and sew expect the silhouette part of 7G wale direction.