• Journal of Gastric Cancer
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• v.12 no.4
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• pp.223-231
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• 2012

Purpose: Clinical staging of gastric cancer appears to be important more and more for tailored therapy. This study aimed to verify the accuracy of clinical T staging in a low-volume institute. Materials and Methods: We retrospectively reviewed prospectively collected data of gastric cancer patients who underwent resection. A total of 268 patients of gastric cancer were enrolled from March 2004 to June 2012. These demographics, tumor characteristics, and clinical stages were analyzed for identification of diagnostic value of clinical T staging. Results: The predictive values for pT1 of endoscopy and computed tomography were 90.0% and 89.4%, respectively. In detail, the predictive values of endoscopy for pT1a, pT1b, and pT2 or more were 87%, 58.5%, and 90.6%, respectively. The predictive values of computed tomography for pT1a, pT1b, and pT2 or more were 68.8%, 73.9%, and 84.4%, respectively. The factors leading to underestimation of pT2 or more lesions by gastroscopy were the middle third location, the size greater than 2 cm, and younger age. Those for overestimation of pT1 lesion by computed tomography were male, age more than 70 years, elevated type, and size greater than 3 cm. Conclusions: Diagnostic accuracy of early gastric cancer was 90%, which is comparable to those of high volume center. In patients with early gastric cancer, limited gastrectomy or minimal invasive surgery can be safely introduced at a low volume center also. However, the surgeon of low-volume institute should consider the accuracy of clinical staging before extending the indication of limited treatment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.327-338
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• 2015

Because of impact on the underwater light field, CDOM can influence the accuracy of global satellite-based measurement of ocean chlorophyll and primary productivity. So we investigated the distribution and seasonal variation of CDOM in the East Sea during summer 2009 and 2011. Among them we report two distinctively different summer cases between 2009 and 2011 year, in which showed the different main sources for CDOM. Regulating factors and sources of CDOM in the East Sea were examined. Comparison between in situ and satellite derived Chl a and CDOM were made to find an influence of CDOM on measurement of satellite derived Chl a. Similar pattern and matching of MODIS Chl a with in situ Chl a 2009 was comparable, but significant discrepancy between MODIS Chl a and in situ Chl a was found, when CDOM was high in summer of 2011. GOCI data showed better matching with in situ data for both Chl a and CDOM, compared to MODIS data in summer of 2011. The presence of high CDOM at the surface layer supplied by vertical mixing seems to affect on the overestimation of Chl a by satellite data.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.569-578
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• 2017

Objective: The purposes of this experiment are an analysis of accuracy between target force level and subjective rating for the Target Force Level and an analysis of the patterns of subjective rating depending on target force level when there is no feedback from males for analysis. Background: The study of perceived exertion about the static contraction is processed with using among the matching procedure method between contralateral limbs, Exertion vs. Borg CR-10 scale and Exertion vs. %MVC (Maximum Voluntary Contraction). However, when there is no feedback, there is lack of the study on whether the subject can distinguish the subjective rating of the force depending on the target force levels. Method: Total 30 males, healthy subjects are measured the maximum grip strength, MVC, and then, each subject is measured the subjective rating and the accuracy with the random target force level (10, 20, 30, 40, 50, 60, 70, 80, and 90% MVC). Results: In the MVC study, males exerted 256.87N (${\pm}51.33$). In the subjective rating of grip strength increased for each Target Force Level (9 levels), higher subjective rating evaluated (p<0.05). In accuracy examination between target force level and subjective rating of grip strength by each %MVC, 10, 30, 40, 50, 70, 90% target force levels showed accurate strength (p>0.05). However, at 20% target force level, the subjects evaluated less subjective rating of grip strength than the target force (Underestimation), and at 60% and 80% target force level, the subjects evaluated more subjective rating of grip strength than the target force (Overestimation) (p<0.05). Conclusion: In the experiment, the MVC showed 256.87N (${\pm}51.33$) for the male adults and as the subjective rating value increased for each Target Force Level (9 levels), higher subjective rating evaluated (p<0.05). Moreover, the results of the accuracy test between target forces and subjective rating of the subjects showed that most participants rated a fairly accurate assessment of subjective rating of grip strength for Target Force Level (9 levels), except for 20%, 60%, and 80%MVC. Application: This experimental result would be used for basic data for the subjective rating of grip strength pattern by the target force level when the voluntary muscle is contracted.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4717-4721
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• 2014

Background: Dosimetric comparison of two dimensional (2D) radiography and three-dimensional computed tomography (3D-CT) based dose distributions with high-dose-rate (HDR) intracavitry radiotherapy (ICRT) for carcinoma cervix, in terms of target coverage and doses to bladder and rectum. Materials and Methods: Sixty four sessions of HDR ICRT were performed in 22 patients. External beam radiotherapy to pelvis at a dose of 50 Gray in 27 fractions followed by HDR ICRT, 21 Grays to point A in 3 sessions, one week apart was planned. All patients underwent 2D-orthogonal and 3D-CT simulation for each session. Treatment plans were generated using 2D-orthogonal images and dose prescription was made at point A. 3D plans were generated using 3D-CT images after delineating target volume and organs at risk. Comparative evaluation of 2D and 3D treatment planning was made for each session in terms of target coverage (dose received by 90%, 95% and 100% of the target volume: D90, D95 and D100 respectively) and doses to bladder and rectum: ICRU-38 bladder and rectum point dose in 2D planning and dose to 0.1cc, 1cc, 2cc, 5cc, and 10cc of bladder and rectum in 3D planning. Results: Mean doses received by 100% and 90% of the target volume were $4.24{\pm}0.63$ and $4.9{\pm}0.56$ Gy respectively. Doses received by 0.1cc, 1cc and 2cc volume of bladder were $2.88{\pm}0.72$, $2.5{\pm}0.65$ and $2.2{\pm}0.57$ times more than the ICRU bladder reference point. Similarly, doses received by 0.1cc, 1cc and 2cc of rectum were $1.80{\pm}0.5$, $1.48{\pm}0.41$ and $1.35{\pm}0.37$ times higher than ICRU rectal reference point. Conclusions: Dosimetric comparative evaluation of 2D and 3D CT based treatment planning for the same brachytherapy session demonstrates underestimation of OAR doses and overestimation of target coverage in 2D treatment planning.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.335-343
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• 2020

Objectives: The Korean Ministry of Environment has identified cases of people suspected of suffering lung disease potentially caused by polyhexamethylene guanidine (PHMG) used in humidifier disinfectants (HDs). Exposure assessment for the HDs was conducted using a questionnaire during face-to-face interview. The main purposes of this study were to develop a methodology to effectively classify levels of exposure to HDs based on a questionnaire. Methods: We first identified the overall participants' exposure characteristics by HD exposure levels; Second, we selected misclassified subjects and investigated characteristics of overestimated and underestimated subjects, focusing on exposure cases to PHMG-containing HDs. An inhalation reference concentration (RfC) for PHMG was produced on the basis of inhalation toxicity values. We made a cross-tabulation of the exposure classes (Exposure classes 1-to-4) by clinical classes based on the RfC. When the value of the exposure class minus the clinical class was 0 or 1, we assumed these were true values. When the value was ≥2 and ≤ -2, we assigned these cases to the overestimation group and underestimation group, respectively. Results: The overestimated group may have already recovered and responded excessively due to psychological anxiety or in order to receive compensation. On the other hand, relatively high mortality rates and surrogate responses for those under 10 years of age may have resulted in inaccurate exposure assessment for underestimated groups. For the characteristics of exposure, it was shown that for the underestimated group, the exposure was relatively weaker than the overestimated group, even though a high overall clinical rating was determined. Conclusions: This study may suggest ways to reduce bias and overcome the limitations of current HD exposure assessment.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.38-50
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• 2020

The purpose of this study is to identify the risks to financial institutions in terms of expanding potential risks due to the deferral of exposure, by identifying the structures in which real estate finance and financial institutions affect real estate prices at low interest rates. To this end, real estate financing is categorized according to the method of financing and the type of value measurement from a risk management perspective and analyzed for each case. As a result of analysis, in the case of profitable real estate, the rate of real estate is increased by directly decreasing the cap rate and directly affecting the fair value calculation method. In the case of non-profitable real estate, the real estate price is increased by expanding the leverage width of investors or financial institutions. Through the analysis of this case, the continuous increase in real estate prices over the past 10 years has the potential to prevent financial institutions from losing under the circumstances such as the growth of real estate finance due to the advancement of the financial market and the continued low interest rate trend that has continued for 10 years. It is judged that the deferred delay is part of the cause, which leads to an increase in the risk to financial institutions.

• Journal of The Korean Association For Science Education
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• v.21 no.3
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• pp.506-515
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• 2001

Understanding the students' ability and tendency of self assessment is one of the important factors in helping their learning and in giving the appropriate feedbacks. The purposes of this study is to analyse the coincidency of the students' self-assessment with the teacher assessment, and the tendency of over and under estimation. The students performed open investigations and assessed their process skills by checking their investigation reports with a given checklist. The total mean of the 'Self-Assessment Capability(SAC)' was 0.73 by 1. The SAC was related to the achievement, not to the gender. The correlation between SAC and achievement was significantly positive(r=0.7, p<.01), and for the girls, the tendency was remarkable. Among the five areas of process skills of open investigation, students got the highest SAC score in the managing and interpreting data area, and the lowest SAC in the drawing conclusion area. The mean of 'Self-Assessment Tendency(SAT)' for all items showed that students overestimated their process skills. While the high achievement students underestimated their process skills, the middle and low showed the tendency of overestimation.

• Tuberculosis and Respiratory Diseases
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• v.72 no.3
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• pp.302-309
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• 2012

Background: Korean regression models for spirometric reference values are different from those of Americans. Using spirometry results of Korean adults, goodness-of-fits of the Korean and the USA Caucasian regression models for forced vital capacity (FVC) and forced expiratory volume in one second ($FEV_1$) were compared. Methods: The number of study participants was 2,360 (1,124 males and 1,236 females). Spirometry was performed under the guidelines of the American Thoracic Society and the European Respiratory Society. After excluding unsuitable participants, spirometric data for 729 individuals (105 males and 624 females) was included in the statistical analysis. The estimated FVC and $FEV_1$ values were compared with those measured. Goodness-of-fits for Korean and USA Caucasian models were compared using an F-test. Results: In males, the expected values of FVC and $FEV_1$ using the Korean model were 12.5% and 5.7% greater than those measured, respectively. The corresponding values for the USA Caucasian model were 3.5% and 0.6%. In females, the difference in FVC and $FEV_1$ were 13.5% and 7.7% for the Korean model, and 6.3% and 0.4% for the USA model, respectively. Goodness-of-fit for the Korean model regarding FVC was not good to the study population, but the Korean regression model for $FEV_1$, and the USA Caucasian models for FVC and $FEV_1$ showed good fits to the measured data. Conclusion: These results suggest that the USA Caucasian model correlates better to the measured data than the Korean model. Using reference values derived from the Korean model can lead to an overestimation regarding the prevalence of abnormal lung function.

• Korean Journal of Remote Sensing
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• v.33 no.5_1
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• pp.599-605
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• 2017

Accurate cloud discrimination in satellite images strongly affects accuracy of remotely sensed parameter produced using it. Especially, cloud contaminated pixel over ocean is one of the major error factors such as Sea Surface Temperature (SST), ocean color, and chlorophyll-a retrievals,so accurate cloud detection is essential process and it can lead to understand ocean circulation. However, static threshold method using real-time algorithm such as Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Himawari Imager (AHI) can't fully explained reflectance variability over ocean as a function of relative positions between the sun - sea surface - satellite. In this paper, we assembled a reflectance spectral library as a function of Solar Zenith Angle (SZA) and Viewing Zenith Angle (VZA) from ocean surface reflectance with clear sky condition of Advanced Himawari Imager (AHI) identified by NOAA's cloud products and spectral library is used for applying the Dynamic Time Warping (DTW) to detect cloud pixels. We compared qualitatively between AHI cloud property and our results and it showed that AHI cloud property had general tendency toward overestimation and wrongly detected clear as unknown at high SZA. We validated by visual inspection with coincident imagery and it is generally appropriate.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.415-426
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• 2015

Solar radiation under a clear sky is a important factor in the process by which meteorological satellite images are converted into solar radiation maps, and the quality of estimations depends on the accuracy of clear sky models. Therefore, it is important to select models appropriate to the purpose of the study and the study area. In this instance, complex models were applied using Linke turbidity, including ESRA, Dumortier, and MODTRAN, in addition to simple models such as Bourges and PdBV, which consider only the solar elevation angles. The presence of cloud was identified using the Communication, Ocean, and Meteorological Satellite and the Meteorological imager (COMS MI), and reference data were then selected. In order to calculate the accuracy of the clear sky models, the concepts of RMSE and MBE were applied. The results show that Bourges and PdBV produced low RMSE values, while PdBV had relatively steady RMSE values. Also, simple models tend to underestimate global solar irradiation during spring and early summer. Conversely, in the winter season, complex methods often overestimate irradiation. In future work, the cause of overestimation and other factors will be analyzed and the clear sky models will be adjusted in order to make them suitable for the Korean Peninsula.