• Title/Summary/Keyword: time series data analysis

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1SWASP J093010.78+533859.5: A Possible Hierarchical Quintuple System

  • Koo, Jae-Rim;Lee, Jae Woo;Lee, Byeong-Cheol;Kim, Seung-Lee;Lee, Chung-Uk;Hong, Kyeongsoo;Lee, Dong-Joo;Rey, Soo-Chang
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.71.1-71.1
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    • 2013
  • Among quadruples or higher multiplicity stars, only a few binary systems have been discovered. They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data show that the brighter object A is an Algol-type detached eclipsing binary with an orbital period of 1.3 days and the fainter B is a W UMa-type contact eclipsing binary with a period of 0.23 days. Using the high-resolution optical spectra, we obtained well-defined radial velocity variations of the system A. Furthermore, stationary spectral lines were detected and should have originated from the other stellar component, which was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to its faintness. We obtained the binary parameters and the absolute dimensions from each light curve synthesis. The primary and secondary components of the system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations at out of eclipses were appeared in both systems, interpreting as the effect of stellar spots on these late spectral type stars. We estimated the distances to the systems A and B individually. They may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).

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An Empirical Study of the Relationships between CO2 Emissions, Economic Growth and Openness (개방화와 경제성장에 따른 한국, 중국, 일본의 이산화탄소 배출량 비교 분석)

  • Choi, Eunho;Heshmati, Almas;Cho, Yongsung
    • Journal of Environmental Policy
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    • v.10 no.4
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    • pp.3-37
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    • 2011
  • This paper investigates the existence of the environmental Kuznets curve (EKC) for carbon dioxide $CO_2$ emissions and its causal relationships with economic growth and openness by using time series data (1971-2006) from China (an emerging market), Korea (a newly industrialized country), and Japan (a developed country). The sample countries span a whole range of development stages from industrialized to newly industrialized and emerging market economies. The environmental consequences according to openness and economic growth do not show uniform results across the countries. Depending on the national characteristics, the estimated EKC show different temporal patterns. China shows an N-shaped curve while Japan has a U-shaped curve. Such dissimilarities are also found in the relationship between $CO_2$ emissions and openness. In the case of Korea, and Japan it represents an inverted U-shaped curve while China shows a U-shaped curve. We also analyze the dynamic relationships between the variables by adopting a vector auto regression or vector error correction model. These models through the impulse response functions allow for analysis of the causal variable's influence on the dynamic response of emission variables, and it adopts a variance decomposition to explain the magnitude of the forecast error variance determined by the shocks to each of the causal variables over time. Results show evidence of large heterogeneity among the countries and variables impacts.

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Effect of Oral Sport Beverages with Medicinal Herbs Added on Short-term Recovery from Exercise-induced Fatigue (한의약소재 스포츠음료수 섭취가 운동-유발성 피로의 단시간 회복에 미치는 영향)

  • Na Hyun-Jong;Lee Kyu-Lark;Kang Ho-Youl
    • The Journal of Korean Medicine
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    • v.27 no.1 s.65
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    • pp.36-46
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    • 2006
  • Objectives : Ginseng Research Group in Korea Food Research Institute developed Saeng Mac San (KFRI-2)and Je Ho Tang (KFRI-3) with their sensory factors more acceptable. And we examined their effects on the short-term recovery capacity for cycling exercise (EX) maintained to all-out. Methods : Seven healthy young subjects (aged $24.0{\pm}2.1yr$) were volunteered at this double blind test. Each of KFRI-2, 3, a commercial sport beverage and control (CON) was offered randomly on a series of EX protocol including 65% VO2max-90min EX (D-ride). 1h-recovery and 85% VO2max EX to all-out (P-ride) under the control of their heart rate (HR) and rating perception of exertion (RPE). Blood samples were collected before D-ride, 30, 60 and 90min in D-ride, 30 and 60min in the recovery period and each 10min in P-ride. Plasma analysis items were glucose, insulin, cortisol (CORT), testosterone (TEST), free fatty acid (FFA), $Na^+$, Cl-and $K^+$. The collected data (Means${\pm}$SE) were analysed by two-way ANOVA and statistically significant differences between treatments (p<0.05) by LSD.; the significant level in FFA, $Na^+$, Cl-and $Na^+$ was p<0.01 Results : At 30min during recovery. plasma glucose level in KFRI-3 was significantly higher than CON, and also insulin in KFRI-3 was than CON and KFRI-2. FFA in KFRI-3 was significantly lower than CON during recovery. $Na^+$ in KFRI-3 significantly higher than CON at 90min in D-ride, and also KFRI-2 was at 60min during recovery. However CORT, TEST, Cl-and $Na^+$ in treated beverages were not significant. KFRI-2, 3 elevated the time for P-ride more than CON did. Conclusions : KFRI-2, 3 elevated the time for P-ride about 12% more than CON did. It is based on rapid recovery of plasma glucose level and inhibition of lipolysis during recovery.

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The Determinants of New Supply in the Seoul Office Market and their Dynamic Relationship (서울 오피스 신규 공급 결정요인과 동태적 관계분석)

  • Yang, Hye-Seon;Kang, Chang-Deok
    • Journal of Cadastre & Land InformatiX
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    • v.47 no.2
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    • pp.159-174
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    • 2017
  • The long-term imbalances between supply and demand in office market can weaken urban growth since excessive supply of offices led to office market instability and excessive demand of offices weakens growth of urban industry. Recently, there have been a lot of new large-scale supplies, which increased volatility in Seoul office market. Nevertheless, new supply of Seoul office has not been fully examined. Given this, the focus of this article was on confirming the influences of profitability, replacement cost, and demand on new office supplies in Seoul. In examining those influences, another focus was on their relative influences over time. For these purposes, we analyzed quarterly data of Seoul office market between 2003 and 2015 using a vector error correction model (VECM). As a result, in terms of the influences on the current new supply, the impact of supply before the first quarter was negative, while that of office employment before the first quarter was positive. Also, that of interest rate before the second quarter was positive, while those of cap rate before the first quarter and cap rate before the second quarter were negative. Based on the findings, it is suggested that prediction models on Seoul offices need to be developed considering the influences of profitability, replacement cost, and demand on new office supplies in Seoul.

Estimating Spatio-Temporal Distribution of Climate Factors in Andong Dam Basin (안동댐 유역 기상인자의 시공간분포 추정)

  • Lim, Chul Hee;Moon, Joo Yeon;Lim, Yoon Jin;Kim, Sea Jin;Lee, Woo Kyun
    • Journal of Korean Society for Geospatial Information Science
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    • v.23 no.4
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    • pp.57-65
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    • 2015
  • This study investigates characteristics of time series spatial distribution on climate factors in Andong Dam basin by estimating precise spatio-temporal distribution of hydro-meteorological information. A spatio-temporal distribution by estimating Semi-Variogram based on spatial autocorrelation was examined using the data from ASOS and 7 hydro-meteorological observatories in Andong Dam basin of upper Nakdonggang River, which were installed and observed by NIMR(National Institute of Meterological Research). Also, temperature and humidity as climate variables were analyzed and it was recognized that there is a variability in watershed area by time and months. Regardless of season, an equal spatial distribution of temperature at 14 o'clock and humidity at 10 o'clock was identified, and nonequal distribution was noticed for both variables at 18 o'clock. From monthly spatial analysis, the most unequal distribution of temperature was seen in January, and the most equal distribution was detected in September. The most unequal distribution of humidity was identified in May, and the most equal distribution was seen in January. Unlike in forest, seasonal spatial distribution characteristics were less apparent;but temperature and humidity had respective characteristics in hydro-meteorology.

A Study on the UAV-based Vegetable Index Comparison for Detection of Pine Wilt Disease Trees (소나무재선충병 피해목 탐지를 위한 UAV기반의 식생지수 비교 연구)

  • Jung, Yoon-Young;Kim, Sang-Wook
    • Journal of Cadastre & Land InformatiX
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    • v.50 no.1
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    • pp.201-214
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    • 2020
  • This study aimed to early detect damaged trees by pine wilt disease using the vegetation indices of UAV images. The location data of 193 pine wilt disease trees were constructed through field surveys and vegetation index analyses of NDVI, GNDVI, NDRE and SAVI were performed using multi-spectral UAV images at the same time. K-Means algorithm was adopted to classify damaged trees and confusion matrix was used to compare and analyze the classification accuracy. The results of the study are summarized as follows. First, the overall accuracy of the classification was analyzed in order of NDVI (88.04%, Kappa coefficient 0.76) > GNDVI (86.01%, Kappa coefficient 0.72) > NDRE (77.35%, Kappa coefficient 0.55) > SAVI (76.84%, Kappa coefficient 0.54) and showed the highest accuracy of NDVI. Second, K-Means unsupervised classification method using NDVI or GNDVI is possible to some extent to find out the damaged trees. In particular, this technique is to help early detection of damaged trees due to its intensive operation, low user intervention and relatively simple analysis process. In the future, it is expected that the utilization of time series images or the application of deep learning techniques will increase the accuracy of classification.

Comparison of Co-registration Algorithms for TOPS SAR Image (TOPS 모드 SAR 자료의 정합기법 비교분석)

  • Kim, Sang-Wan
    • Korean Journal of Remote Sensing
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    • v.34 no.6_1
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    • pp.1143-1153
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    • 2018
  • For TOPS InSAR processing, high-precision image co-registration is required. We propose an image co-registration method suitable for the TOPS mode by comparing the performance of cross correlation method, the geometric co-registration and the enhanced spectral diversity (ESD) matching algorithm based on the spectral diversity (SD) on the Sentinel-1 TOPS mode image. Using 23 pairs of interferometric pairs generated from 25 Sentinel-1 TOPS images, we applied the cross correlation (CC), geometric correction with only orbit information (GC1), geometric correction combined with iterative cross-correlation (GC2, GC3, GC4), and ESD iteration (ESD_GC, ESD_1, ESD_2). The mean of co-registration errors in azimuth direction by cross correlation and geometric matching are 0.0041 pixels and 0.0016 pixels, respectively. Although the ESD method shows the most accurate result with the error of less than 0.0005 pixels, the error of geometric co-registration is reduced to 0.001 pixels by repetition through additional cross correlation matching between the reference and resampled slave image. The ESD method is not applicable when the coherence of the burst overlap areas is low. Therefore, the geometric co-registration method through iterative processing is a suitable alternative for time series analysis using multiple SAR data or generating interferogram with long time intervals.

Comparison of Observation Performance of Urban Displacement Using ALOS-1 L-band PALSAR and COSMO-SkyMed X-band SAR Time Series Images (ALOS-1 L-band PALSAR와 COSMO-SkyMed X-band SAR 시계열 영상을 이용한 도심지 변위관측 성능 비교 분석)

  • Choi, Jung-Hyun;Kim, Sang-Wan
    • Korean Journal of Remote Sensing
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    • v.34 no.2_1
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    • pp.283-293
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    • 2018
  • We applied PSInSAR to two SAR satellite (ALOS-1 and COSMO-SkyMed) images and analyzed the difference in displacement observation performance according to sensor characteristics. The building layer was extracted from the digital topographic map, and the PS extracted from the SAR image was classified into two groups(building structure and ground surface) for density analysis. The density of PS extracted from the research area was $0.023point/m^2$ for ALOS-1 PALSAR and $0.1point/m^2$ for COSMO-SkyMed, more than 4 times PS was extracted compared to ALOS-1. In addition, not only the PS density in the building, but also the density in the ground were greatly increased. The average displacement velocity of ALOS-1 PALSAR is within ${\pm}1cm/yr$, while for COSMO-SkyMed it is within ${\pm}0.3cm/yr$. Although it is difficult to make quantitative comparisons because it does not use the data for the same period, it can be said that the accuracy of X-band SAR system is very high compared to the L-band. In consideration of PS observation density and observation accuracy of displacement, X-band SAR data is very effective in research where it is important to acquire useful signals from the ground surface, such as ground subsidence and sinkhole.

Validation of OMI HCHO with EOF and SVD over Tropical Africa (EOF와 SVD을 이용한 아프리카 지역에서 관측된 OMI HCHO 자료의 검증)

  • Kim, J.H.;Baek, K.H.;Kim, S.M.
    • Korean Journal of Remote Sensing
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    • v.30 no.4
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    • pp.417-430
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    • 2014
  • We have found an error in the operational OMI HCHO columns, and corrected it by applying a background parameterization derived on a 4th order polynomial fit to the time series of monthly average OMI HCHO data. The corrected OMI HCHO agrees with this understanding as well as with the other sensors measurements and has no unrealistic trends. A new scientific approach, statistical analyses with EOF and SVD, was adapted to reanalyze the consistency of the corrected OMI HCHO with other satellite measurements of HCHO, CO, $NO_2$, and fire counts over Africa. The EOF and SVD analyses with MOPITT CO, OMI $NO_2$, SCIAMAHCY, and OMI HCHO show the overall spatial and temporal pattern consistent with those of biomass burning over these regions. However, some discrepancies were observed from OMI HCHO over northern equatorial Africa during the northern biomass burning seasons: The maximum HCHO was found further downwind from where maximum fire counts occur and the minimum was found in January when biomass burning is strongest. The statistical analysis revealed that the influence of biogenic activity on HCHO wasn't strong enough to cause the discrepancies, but it is caused by the error in OMI HCHO from using the wrong Air Mass Factor (AMF) associated with biomass burning aerosol. If the error is properly taken into consideration, the biomass burning is the strongest source of HCHO seasonality over the regions. This study suggested that the statistical tools are a very efficient method for evaluating satellite data.

Clinical Outcomes and Risk Factors of Traumatic Pancreatic Injuries (외상성 췌장 손상의 임상 결과 및 예후인자)

  • Lee, Hong-Tae;Kim, Jae-Il;Choi, Pyong-Wha;Park, Je-Hoon;Heo, Tae-Gil;Lee, Myung-Soo;Kim, Chul-Nam;Chang, Surk-Hyo
    • Journal of Trauma and Injury
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    • v.24 no.1
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    • pp.1-6
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    • 2011
  • Purpose: Even though traumatic pancreatic injuries occur in only 0.2% to 4% of all abdominal injuries, the morbidity and the mortality rates associated with pancreatic injuries remain high. The aim of this study was to evaluate the clinical outcomes of traumatic pancreatic injuries and to identify predictors of mortality and morbidity. Methods: We retrospectively reviewed the medical records of 26 consecutive patients with a pancreatic injury who underwent a laparotomy from January 2000 to December 2010. The data collected included demographic data, the mechanism of injury, the initial vital signs, the grade of pancreatic injury, the injury severity score (ISS), the revised trauma score (RTS), the Glasgow Coma Scale (GCS), the number of abbreviated injury scales (AIS), the number of associated injuries, the initial laboratory findings, the amount of blood transfusion, the type of operation, the mortality, the morbidity, and others. Results: The overall mortality rate in our series was 23.0%, and the morbidity rate was 76.9%. Twenty patients (76.9%) had associated injuries to either intra-abdominal organs or extra-abdominal organs. Two patients (7.7%) underwent external drainage, and 18 patients (69.3%) underwent a distal pancreatectomy. Pancreaticoduodenectomies were performed in 6 patients (23.0%). Three patients underwent a re-laparotomy due to anastomosis leakage or postoperative bleeding, and all patients died. The univariate analysis revealed 11 factors (amount of transfusion, AAST grade, re-laparotomy, associated duodenal injury, base excess, APACHE 11 score, type of operation, operation time, RTS, associated colon injury, GCS) to be significantly associated with mortality (p<0.05). Conclusion: Whenever a surgeon manages a patient with traumatic pancreatic injury, the surgeon needs to consider the predictive risk factors. And, if possible, the patient should undergo a proper and meticulous, less invasive surgical procedure.