• Title/Summary/Keyword: Correlation time

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A Statistic Correlation Analysis Algorithm Between Land Surface Temperature and Vegetation Index

  • Kim, Hyung-Moo;Kim, Beob-Kyun;You, Kang-Soo
    • Journal of Information Processing Systems
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    • v.1 no.1 s.1
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    • pp.102-106
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    • 2005
  • As long as the effective contributions of satellite images in the continuous monitoring of the wide area and long range of time period, Landsat TM and Landsat ETM+ satellite images are surveyed. After quantization and classification of the deviations between TM and ETM+ images based on approved thresholds such as gains and biases or offsets, a correlation analysis method for the compared calibration is suggested in this paper. Four time points of raster data for 15 years of the highest group of land surface temperature and the lowest group of vegetation of the Kunsan city Chollabuk_do Korea located beneath the Yellow sea coast, are observed and analyzed their correlations for the change detection of urban land cover. This experiment based on proposed algorithm detected strong and proportional correlation relationship between the highest group of land surface temperature and the lowest group of vegetation index which exceeded R=(+)0.9478, so the proposed Correlation Analysis Model between the highest group of land surface temperature and the lowest group of vegetation index will be able to give proof an effective suitability to the land cover change detection and monitoring.

Long and Short Wave Radiation and Correlation Analysis Between Downtown and Suburban Area(II) - Study on Correlation Analysis Method of Radiation Data - (도심부와 교외지역의 장·단파 복사와 상관도 분석 (II) - 관측 자료의 상관도 분석기법에 관한 연구 -)

  • Choi, Dong-Ho;Lee, Bu-Yong;Oh, Ho-Yeop
    • Journal of the Korean Solar Energy Society
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    • v.33 no.4
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    • pp.101-110
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    • 2013
  • The propose of this study is to understand the phenomenon of radiation and comparison of analysis of two methods. One is analysis method of same-time data and the another is analysis method of rank data. We confirmed that two methods of correlation analysis had the effectiveness and suitability. The followings are main results from this study. 1) The seasonal correlation coefficient of long and short-wave radiation is higher in winter than in summer because of high humidity in the summer season can makes easily cloud in the sky locally. 2) According to analysis method, there is big difference in correlation coefficient from 0.494(Analysis method of same-time data) to 0.967(Analysis method of rank data) with short-wave radiation by the location during summer. These results have significant value in solar radiation research and analysis. It has explored a new way for solar radiation research of analysis method as well.

A Study on the Correlation Analysis between the Daily Earthwork Volume and Fine Dust Concentration

  • Dong-Myeong, CHO;Ju-Yeon, LEE;Tae-Hwan, JEONG;Woo-Taeg, KWON
    • Journal of Wellbeing Management and Applied Psychology
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    • v.6 no.1
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    • pp.1-7
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    • 2023
  • Purpose: Fine dust is classified as a group 1 carcinogen and poses a significant environmental problem that urgently requires improvement to protect the environmental rights of citizens. Given the difficulty of implementing measures to reduce overseas sources of fine dust, it is essential to first devise specific measures to address domestic emission sources. As such, this study aims to analyze the correlation between earthwork volume control and fine dust concentration as preliminary management measures to reduce the impact of scattering dust at construction sites. Based on real-time air quality information, field management measures will be presented to mitigate the effects of dust emissions. Research design, data and methodology: As examples, we selected construction sites that had recently undergone small-scale environmental impact assessment consultations. The standard earthwork volume was classified into grades using 20% intervals, and we applied AERMOD to predict the weighted concentration of fine dust based on the earthwork volume class and analyzed its correlation. Results: The results of this study demonstrate a strong correlation between earthwork volume and fine dust concentration. By utilizing the correlation analysis between earthwork volume and fine dust concentration on-site, this finding can be utilized as an effective fine dust management plan. Conclusions: This involves determining the daily earthwork intensity based on real-time air quality information and implementing measures to reduce scattering dust.

Numerical vibration correlation technique analyses for composite cylinder under compression and internal pressure

  • Do-Young Kim;Chang-Hoon Sim;Jae-Sang Park;Joon-Tae Yoo;Young-Ha Yoon;Keejoo Lee
    • Structural Engineering and Mechanics
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    • v.87 no.5
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    • pp.419-429
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    • 2023
  • This study conducts numerical analyses of a thin-walled composite cylinder under axial compression and internal pressure of 10 kPa. Numerical vibration correlation technique and nonlinear postbuckling analyses are conducted using the nonlinear finite element analysis program, ABAQUS. The single perturbation load approach and measured imperfection data are used to represent the geometric initial imperfection of thin-walled composite cylinder. The buckling knockdown factors are derived using present initial imperfection and analysis methods under axial compression without and with the internal pressure. Furthermore, the buckling knockdown factors are compared with the buckling test and computation time are calculated. In this study, derived buckling knockdown factors in present study have difference within 10% as compared with the buckling test. It is shown that nonlinear postbuckling analysis can derive relatively accurate buckling knockdown factor of present thin-walled cylinders, however, numerical vibration correlation technique derives reasonable buckling knockdown factors compared with buckling test. Therefore, this study shows that numerical vibration correlation technique can also be considered as an effective numerical method with 21~91% reduced computation time than nonlinear postbuckling analysis for the derivation of buckling knockdown factors of present composite cylinders.

Analysis on the Performance of $2{\times}1$ Alamouti Scheme in Time-varying and Spatially Correlated Channels (시변 및 공간 상관 채널 환경에서 $2{\times}1$ 알라마우티 구조 (Alamouti Scheme)의 성능 분석)

  • Lee, Eun-Ju;Park, Jae-Don;Yoon, Gi-Wan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2011.05a
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    • pp.539-542
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    • 2011
  • In this paper, we have implemented a performance analysis of $2{\times}1$ Alamouti scheme suggested by Alamouti, composed of the transmit space-time code and the simple linear decoding processing, in perfectly time-varying and spatially correlated channels. In addition, we derived the closed-form probability density function (PDF) of the output signal-to-noise ratio (SNR) and the outage probability of the Alamouti scheme as a function of the spatial correlation coefficient in the consideration of no correlation in time. As a result, it was found that the performance of the Alamouti scheme could be significantly degraded particularly in the case that the channels are time-varying and spatially correlated.

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Correlation between the Time to Surgery and That to Recovery from Postoperative Diplopia Based on a Single-Center, Retrospective Experience: A Case Series of 11 Patients

  • Kim, Nam Hoon;Kang, Seok Joo
    • Archives of Plastic Surgery
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    • v.41 no.5
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    • pp.486-492
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    • 2014
  • Background We conducted this study to identify the correlation between the time to surgery and that to recovery from postoperative diplopia. Methods In the current single-center, retrospective study, we enrolled a total of 11 patients (n=11) who were diagnosed with white-eyed blowout fracture and underwent surgical operation at our institution between January 2009 and January 2013. To identify the correlation between the time to surgery and that to recovery from postoperative diplopia, we divided our patients into the three groups: the group A (time to surgery, <2 days) (n=4), the group B (time to surgery, 3-7 days) (n=4) and the group C (n=3) (time to surgery, 8-60 days). Then, we compared such variables as sex, age, signs of soft tissue injury, preoperative nausea/vomiting, the degree of preoperative diplopia and the side of the fracture on computed tomography scans between the three groups. Results In our series, mean age at the onset of trauma was nine years (range, 5-16 years); the mean time to surgery was 30 days (range, 2-60 days); and the mean follow-up period was one year (range, 6 months-2 years). Our results showed that the time to recovery was shorter in the patients with a shorter time to surgery. Conclusions We found that the degree of recovery from impaired ocular motility and diplopia was the highest in the patients undergoing surgical operations within 48 hours of the onset of trauma with the reconstruction of the fracture sites using implant materials.

Variation of Magnetic Field (By, Bz) Polarity and Statistical Analysis of Solar Wind Parameters during the Magnetic Storm Period

  • Moon, Ga-Hee
    • Journal of Astronomy and Space Sciences
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    • v.28 no.2
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    • pp.123-132
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    • 2011
  • It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME)-driven storms, co-rotating interaction region (CIR)-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF $B_y$ and $B_z$ components (in geocentric solar magnetospheric coordinate system coordinate) during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst) index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of $B_z$ < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF $B_z$ (T1~T4) is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0%) under the $B_z$ < 0 condition. It is found that the correlation is highest between the time-integrated IMF $B_z$ and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is found between timeintegrated $B_z$ and time-integrated Dst index. The relationship between storm size and time lag in terms of hours from $B_z$ minimum to Dst minimum values is investigated. For the CME-driven storms, time lag of 26% of moderate storms is one hour, whereas time lag of 33% of moderate storms is two hours for the CIR-driven storms. The average values of solar wind parameters for the CME and CIR-driven storms are also examined. The average values of ${\mid}Dst_{min}{\mid}$ and ${\mid}B_{zmin}{\mid}$ for the CME-driven storms are higher than those of CIR-driven storms, while the average value of temperature is lower.

Correlation between Colon Transit Time Test Value and Initial Maintenance Dose of Laxative in Children with Chronic Functional Constipation

  • Kim, Mock Ryeon;Park, Hye Won;Son, Jae Sung;Lee, Ran;Bae, Sun Hwan
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.19 no.3
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    • pp.186-192
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    • 2016
  • Purpose: To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. Methods: Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis. Results: The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was $0.68{\pm}0.18g/kg/d$; according to age, the dose was $0.73{\pm}0.16g/kg/d$ (<8 years), $0.53{\pm}0.12g/kg/d$ (8 to <12 years), and $0.36{\pm}0.05g/kg/d$ (12 to 15 years). The dose of lactulose was $1.99{\pm}0.43mL/kg/d$ (<8 years) or $1.26{\pm}0.25mL/kg/d$ (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268, p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267, p=0.022). Conclusion: CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.

Time Series and Groundwater Recharge Analyses Using Water Fluctuation Data in Mountain Geumjeong Area (금정산지역의 수위변동 자료를 이용한 시계열 및 지하수 함양량 분석)

  • Kim, Tae-Won;Hamm, Se-Yeong;Cheong, Jae-Yeol;Ryu, Sang-Min;Lee, Jeong-Hwan;Son, Keon-Tae;Kim, Nam-Hoon
    • Journal of Environmental Science International
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    • v.17 no.2
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    • pp.257-267
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    • 2008
  • Groundwater recharge characteristics in a fractured granite area, Mt. Geumjeong, Korea. was interpreted using bedrock groundwater and wet-land water data. Time series analysis using autocorreclation, cross-correlation and spectral density was conducted for characterizing water level variation and recharge rate in low water and high water seasons. Autocorrelation analysis using water levels resulted in short delay time with weak linearity and memory. Cross-correlation function from cross-correlation analysis was lower in the low water season than the high water season for the bedrock groundwater. The result of water level decline analysis identified groundwater recharge rate of about 11% in the study area.

Experimental Study on the Accumulation of Cadmium and Other Metals in the Fish Bodies(Oryzias latipes) (송사리(Oryzias latipes)의 생체내 카드뮴 및 미량금속의 축적에 관한 실험적 연구)

  • 조영채;송인순;박상환
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.25-31
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    • 2000
  • In order to assess the accumulation levels of cadmium and other metals(Zn, Cu, Ca and Fe) in fish bodies, an experimental study was performed by raising fry of "Oryzias latipes" in the water containing cadmium 0.03 ppm, cadmium 0.03 ppm + zinc 0.03 ppm and in the tap water(control group) were made. In the results the concentration of Cd in fish bodies were increased with advancing exposure time in Cd 0.03 ppm treated group and 0.03 ppm + Zn 0.03 ppm treated group, but there was no significantly different between both groups with Cd concentration in each week. The concentration of Zn in fish bodies was no changed with advancing exposure time in control group and Cd 0.03 ppm + Zn 0.03 ppm treated group were significantly different from control and Cd 0.03 ppm treated group. The concentration of Cu, Ca and Fe in fish bodies were increased with advancing exposure time, and control group was higher than any other groups. Simple correlation analysis showed that the positive correlation between Cd and Zn, Cu and Ca, Fe, Ca and Fe, but Cd was negative correlation with Cu, Ca and Fe. In conclusion, we investigated a tendency that the concentration of Cd and Zn in fish bodies tended to increase with the lapse of time, but Cu was unchanged and those of Ca and Fe were decreased in administrating the trace dose of Cd and Zn in water. in water.

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