• Title/Summary/Keyword: Data validation

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Clinical significance of APOB inactivation in hepatocellular carcinoma

  • Lee, Gena;Jeong, Yun Seong;Kim, Do Won;Kwak, Min Jun;Koh, Jiwon;Joo, Eun Wook;Lee, Ju-Seog;Kah, Susie;Sim, Yeong-Eun;Yim, Sun Young
    • Experimental and Molecular Medicine
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    • v.50 no.11
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    • pp.7.1-7.12
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    • 2018
  • Recent findings from The Cancer Genome Atlas project have provided a comprehensive map of genomic alterations that occur in hepatocellular carcinoma (HCC), including unexpected mutations in apolipoprotein B (APOB). We aimed to determine the clinical significance of this non-oncogenetic mutation in HCC. An Apob gene signature was derived from genes that differed between control mice and mice treated with siRNA specific for Apob (1.5-fold difference; P < 0.005). Human gene expression data were collected from four independent HCC cohorts (n = 941). A prediction model was constructed using Bayesian compound covariate prediction, and the robustness of the APOB gene signature was validated in HCC cohorts. The correlation of the APOB signature with previously validated gene signatures was performed, and network analysis was conducted using ingenuity pathway analysis. APOB inactivation was associated with poor prognosis when the APOB gene signature was applied in all human HCC cohorts. Poor prognosis with APOB inactivation was consistently observed through cross-validation with previously reported gene signatures (NCIP A, HS, high-recurrence SNUR, and high RS subtypes). Knowledge-based gene network analysis using genes that differed between low-APOB and high-APOB groups in all four cohorts revealed that low-APOB activity was associated with upregulation of oncogenic and metastatic regulators, such as HGF, MTIF, ERBB2, FOXM1, and CD44, and inhibition of tumor suppressors, such as TP53 and PTEN. In conclusion, APOB inactivation is associated with poor outcome in patients with HCC, and APOB may play a role in regulating multiple genes involved in HCC development.

Assessment of Water Quality Calibration Criteria for Field-Scale Water Quality Model

  • Seong, Choung-Hyun;Kim, Sang-Min;Park, Seung-Woo;Park, Tae-Yang;Kim, Sung-Jae;Jung, Ki-Woong
    • Journal of agriculture & life science
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    • v.44 no.5
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    • pp.101-107
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    • 2010
  • The objective of this study was to assess the statistics and associated criteria for field-scale model used to simulate nutrient concentrations in paddy field. CREAMS-PADDY, a modified version of the field-scale CREAMS model, simulates the hydrologic, sediment, and nutrient cycles in paddy fields was applied in this study. The model was calibrated and validated using data from study rice paddy fields in Republic of Korea. The calibration statistics include mean and the minimum-maximum range associated with a "temporal window" that spans a period of several days. Because nutrient concentrations in paddy filed are typically sampled infrequently (on a weekly basis, at best) and represent only an instant in time, it is not reasonable to expect any model to simulate a daily average concentration equal to an observed value on a particular day. The 5-day window and related calibration statistics were applied in this study and the applicability of this concept was tested for field-scale water quality model. As a result of calibration and validation, the ponded water nutrient concentration values showed only small changes except the fertilization period. Because of the small changes in ponded water concentration, the size of 5-day window was too small to capture the observed values. Further study is required to establish the 5-day window calibration method for field-scale water quality modeling.

Development of Stem Profile and Taper Equation for Carpinus laxiflora in Jeju Experimental Forests of Korea Forest Research Institute (국립산림과학원 제주시험림의 서어나무 수간형태와 수간곡선식 추정)

  • Chung, Young-Gyo;Kim, Dae-Hyun;Kim, Cheol-Min
    • Journal of agriculture & life science
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    • v.44 no.4
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    • pp.1-7
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    • 2010
  • Data was collected to develop equation for predicting stemp taper for Carpinus laxiflora in Jeju Experimental Forests. The Models tested for choosing the best-fit equations were Max & Burkhart's model, Kozak's model, and Lee's model. Performance of the equations in predicting stem diameter at a specific point along a stem was evaluated with fit and validation statistics and distribution of residuals on predicted values. In result, all the three models gave slightly better values of fitting statistics. In plotting residuals against predicted diameter, Max & Burkhart's model showed underestimation in predicting small diameter and Lee's Model did the same in predicting small diameter. Based on the above analysis of the three models in predicting stem taper, Kozak's model was chosen for the best-fit stem taper equations, and its parameters were given for C. laxiflora. Kozak's model was used to develop a stem volume table of outside bark for C. laxiflora.

Landslide Detection and Landslide Susceptibility Mapping using Aerial Photos and Artificial Neural Networks (항공사진을 이용한 산사태 탐지 및 인공신경망을 이용한 산사태 취약성 분석)

  • Oh, Hyun-Joo
    • Korean Journal of Remote Sensing
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    • v.26 no.1
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    • pp.47-57
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    • 2010
  • The aim of this study is to detect landslide using digital aerial photography and apply the landslide to landslide susceptibility mapping by artificial neural network (ANN) and geographic information system (GIS) at Jinbu area where many landslides have occurred in 2006 by typhoon Ewiniar, Bilis and Kaemi. Landslide locations were identified by visual interpretation of aerial photography taken before and after landslide occurrence, and checked in field. For landslide susceptibility mapping, maps of the topography, geology, soil, forest, lineament, and landuse were constructed from the spatial data sets. Using the factors and landslide location and artificial neural network, the relative weight for the each factors was determinated by back-propagation algorithm. As the result, the aspect and slope factor showed higher weight in 1.2-1.5 times than other factors. Then, landslide susceptibility map was drawn using the weights and finally, the map was validated by comparing with landslide locations that were not used directly in the analysis. As the validation result, the prediction accuracy showed 81.44%.

Validation and selection of GCPs obtained from ERS SAR and the SRTM DEM: Application to SPOT DEM Construction

  • Jung, Hyung-Sup;Hong, Sang-Hoon;Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.24 no.5
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    • pp.483-496
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    • 2008
  • Qualified ground control points (GCPs) are required to construct a digital elevation model (DEM) from a pushbroom stereo pair. An inverse geolocation algorithm for extracting GCPs from ERS SAR data and the SRTM DEM was recently developed. However, not all GCPs established by this method are accurate enough for direct application to the geometric correction of pushbroom images such as SPOT, IRS, etc, and thus a method for selecting and removing inaccurate points from the sets of GCPs is needed. In this study, we propose a method for evaluating GCP accuracy and winnowing sets of GCPs through orientation modeling of pushbroom image and validate performance of this method using SPOT stereo pair of Daejon City. It has been found that the statistical distribution of GCP positional errors is approximately Gaussian without bias, and that the residual errors estimated by orientation modeling have a linear relationship with the positional errors. Inaccurate GCPs have large positional errors and can be iteratively eliminated by thresholding the residual errors. Forty-one GCPs were initially extracted for the test, with mean the positional error values of 25.6m, 2.5m and -6.1m in the X-, Y- and Z-directions, respectively, and standard deviations of 62.4m, 37.6m and 15.0m. Twenty-one GCPs were eliminated by the proposed method, resulting in the standard deviations of the positional errors of the 20 final GCPs being reduced to 13.9m, 8.5m and 7.5m in the X-, Y- and Z-directions, respectively. Orientation modeling of the SPOT stereo pair was performed using the 20 GCPs, and the model was checked against 15 map-based points. The root mean square errors (RMSEs) of the model were 10.4m, 7.1m and 12.1m in X-, Y- and Z-directions, respectively. A SPOT DEM with a 20m ground resolution was successfully constructed using a automatic matching procedure.

Aerosol Optical Thickness Retrieval Using a Small Satellite

  • Wong, Man Sing;Lee, Kwon-Ho;Nichol, Janet;Kim, Young J.
    • Korean Journal of Remote Sensing
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    • v.26 no.6
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    • pp.605-615
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    • 2010
  • This study demonstrates the feasibility of small satellite, namely PROBA platform with the compact high resolution imaging spectrometer (CHRIS), for aerosol retrieval in Hong Kong. The rationale of our technique is to estimate the aerosol reflectances by decomposing the Top of Atmosphere (TOA) reflectances from surface reflectance and Rayleigh path reflectances. For the determination of surface reflectances, the modified Minimum Reflectance Technique (MRT) is used on three winter ortho-rectified CHRIS images: Dec-18-2005, Feb-07-2006, Nov-09-2006. For validation purpose, MRT image was compared with ground based multispectral radiometer measurements and atmospherically corrected Landsat image. Results show good agreements between CHRIS-derived surface reflectance and both by ground measurement data as well as by Landsat image (r>0.84). The Root-Mean-Square Errors (RMSE) at 485, 551 and 660nm are 0.99%, 1.19%, and 1.53%, respectively. For aerosol retrieval, Look Up Tables (LUT) which are aerosol reflectances as a function of various AOT values were calculated by SBDART code with AERONET inversion products. The CHRIS derived Aerosol Optical Thickness (AOT) images were then validated with AERONET sunphotometer measurements and the differences are 0.05~0.11 (error=10~18%) at 440nm wavelength. The errors are relatively small compared to those from the operational moderate resolution imaging spectroradiometer (MODIS) Deep Blue algorithm (within 30%) and MODIS ocean algorithm (within 20%).

Perspectives on the Applicatio of Remote Sensing for Observation of Ocean Environments (해양환경관측을 위한 원격탐사의 활용과 그 전망)

  • 유신재;정종철
    • Korean Journal of Remote Sensing
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    • v.15 no.3
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    • pp.277-288
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    • 1999
  • The aim of this review is to provide perspectives on the application of remote sensing techniques for observation of marine environmental changes on various spatio-temporal scales. Currently available remote sensing technologies are reviewed and future direction is suggested. For better utilization of remote sensing, a comprehensive plan should be developed by a demand-side and problem-solving approach. Marine environmental changes should be observed on proper spatio-temporal scales where the processes occur. For appropriate observation and monitoring of various environmental changes in coastal regions, more sensors must be utilized. Platforms other than satellites should also be utilized to expand the spatio-temporal scales of observation. Calibration/validation activities, required for accurate interpretation of remotely sensed data, could utilize buoys and ship-of-opportunity sensors. It is desirable that such systems by developed as a part of an integrated monitoring network.

The Study on the Extraction of the Distribution Potential Area of Debris Landform Using Fuzzy Set and Bayesian Predictive Discriminate Model (퍼지집합과 베이지안 확률 기법을 이용한 암설사면지형 분포지역 추출에 관한 연구)

  • Wi, Nun-Sol;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.3
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    • pp.105-118
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    • 2017
  • The debris slope landforms which are existent in Korean mountains is generally on the steep slopes and mostly covered by vegetation, it is difficult to investigate the landform. Therefore a scientific method is required to come up with an effective field investigation plan. For this purpose, the use of Remote Sensing and GIS technologies for a spatial analysis is essential. This study has extracted the potential area of debrisslope landform formation using Fuzzy set and Bayesian Predictive Discriminate Model as mathematical data integration methods. The first step was to obtain information about debris locations and their related factors. This information was verified through field investigation and then used to build a database. In the second step, the map that zoning the study area based on the degree of debris formation possibility was generated using two modeling methods, and then cross validation technique was applied. In order to quantitatively analyze the accuracy of two modeling methods, the calculated potential rate of debrisformation within the study area was evaluated by plotting SRC(Success Rate Curve) and calculating AUC(Area Under the Curve). As a result, the prediction accuracy of Fuzzy set model wes 83.1% and Bayesian Predictive Discriminate Model wes 84.9%. It showed that two models are accurate and reliable and can contribute to efficient field investigation and debris landform management.

Development and Application of the Korean Prototype of Wellness Index (한국형 웰니스 인덱스 원안 개발과 적용)

  • Lee, Insook;Bang, Kyung-Sook;Kim, Sungjae;Lee, Juna;Jo, Juhyun
    • Perspectives in Nursing Science
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    • v.16 no.2
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    • pp.84-97
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    • 2019
  • Purpose: This study aimed to develop the Korean Prototype of Wellness Index (KP-WI) and identify the relationship between Koreans' health characteristics and wellness. Methods: The Wellness Index (WI) was translated into the primitive version of the KP-WI, considering the Koreans' culture and health behavior. It was administered to 223 service industrial employees at one workplace along with the Positive Affect and Negative Affect Schedule (PANAS) and Stress Questionnaire-Short Form. Data analyses included item-total correlation, Pearson's correlation coefficient, independent t-test, and one-way ANOVA. Results: The primitive version was modified to KP-WI based on the item-total correlation. The items considered to lower the reliability of the KP-WI were eliminated. Cronbach's ${\alpha}$ for each subscale ranged from .857 to .939. Perceived stress and negative emotions correlated significantly with wellness measured by KP-WI (r=-.29, p<.001; r=-.27, p<.001). Positive emotions correlated significantly with wellness (r=.60, p<.001). Conclusion: This study contributes to the development of Korean-style wellness indexes by developing a prototype and exploring the factors related to wellness.

The Analysis of Flood in an Ungauged Watershed using Remotely Sensed and Geospatial Datasets (I) - Focus on Estimation of Flood Discharge - (원격탐사와 공간정보를 활용한 미계측 유역 홍수범람 해석에 관한 연구(I) - 홍수량 산정을 중심으로 -)

  • Son, Ahlong;Kim, Jongpil
    • Korean Journal of Remote Sensing
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    • v.35 no.5_2
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    • pp.781-796
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    • 2019
  • This study attempted to simulate the flood discharge in the Duman River basin containing Hoeryong City and Musan County of North Korea where were damaged from Typhoon Lionrock on August, 2016. For hydrological modelling remotely sensed datasets were used to estimate watershed properties and hydrologic factors because the basin is ungauged where hydrological observation is not exist or sparse. For validation we applied our methodology and datasets to the Soyanggang Dam basin. It has not only similar shape factor and compactness ratio to those of the target basin but also accurate, adequate, and abundant measurements. The results showed that the flood discharge from Typhoon Lionrock corresponded to three to five years design floods in the Duman River basin. This indicate that the Duman River basin has a high risk of flood in the near future. Finally this study demonstrated that remotely sensed data and geographic information could be utilized to simulate flood discharge in an ungauged watershed.