• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.2
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• pp.59-66
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• 2018

This study examined the correlation among topography, forest type, soil and geology in Inje area where landslides occurred during heavy rainfall from July 11 to July 18, 2006 to assess the landslide susceptibility. In order to assess the susceptibility of future landslides, landslides occurred in Inje area were classified into slide type and flow type, and slope angle, aspect, curvature, ridge and valley were extracted from the area. The landslide susceptibility was assessed by applying diameter class, age class, density, and forest type to Bayesianbased LR (Logistic Regression) model and WOE (Weight of Evidence) model, and the fitness of modeling was verified by predict rate curve. As the results of susceptibility assessment, using all landslides without no distintion, it was found that 75% of the LR model and 73% of the WOE model were fit in terms of the top 20% of the landslides. According to slide type and flow type in the top 20% of the landslides, it was found that 71% of the LR model and 69% of the WOE model were fit in terms of the slide type. Whereas, it was found that 86% of the LR model and 82% of the WOE model were fit in terms of the flow type. That is, the results of the LR model showed higher fitness than the results of the WOE model, and the fitness of the flow type was higher than that of the slide type. Consequently, it suggests that it is reasonable to assess and verify the landslide susceptibility according to the types of landslides.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.357-365
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• 2011

The current trends in steel construction intend to use tapered sections to minimize as much as possible the use of excess material. This can be done by choosing the cross-sections to be as economical as possible, leaving the classical approach of using prismatic members. In addition, it is important to predict the buckling behavior of tapered member with large depth-to-thickness ratio in order to prevent the collapse of PEB system subjected to overloads. An experimental investigation of buckling behavior of tapered beam was presented. The primary test parameter was depth-to-thickness ratio and taper ratio. Using initial stiffness and load-carrying capacity proposed by current provision, the simple plastic hinge method using modified Yoda's model and finite element analysis, the prediction of a moment-rotation curve of linearly tapered member was presented. Moreover, comparisons between analytical and experimental data for moment-rotation curves were accomplished.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.250-250
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• 1990

In this paper, fatigue tests were carried out at stress test levels of 461 MPa, 441 MPa, and 431 MPa by using smooth specimen of$2_{1/4}$ Cr-1 Mo steel with the stress ratio(R) of 0.05. The initiation, growth and coalescense process of the major cracks and sub-cracks among the fatigue cracks on the smooth specimen are investigated and measured under each stress level at a constant cycle ratio by the replica technique with optical microscope. Some of the important results are as follows: In spite of the difference of stress levels, the major crack data gather into a small band in the curve of surface crack length and crack depth against cycle ratio N/Nf. The sub-crack data, however, deviate from the band of the major crack. The growth rates, da/dN, of major and sub-crack plotted against the stress intensity factor range, ${\Delta}K$, have the tendency to be compressed on a relatively small band. But it is more effective to predict fatigue life through major cracks. The propagation behavior of surface microcracks on the smooth specimens coincides with that of the specimen having an artificial small surface defect or through crack.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.539-546
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• 2019

Liver biopsy is invasive and it is a risk of complications. Nevertheless, liver biopsy is gold standard for predicting liver fibrosis. To compensate for these shortcomings, in this study, the liver fibrosis stage was divided using Fibroscan(R) in 200 chronic hepatitis C patients. And, the usefulness and cut-off values of fibrosis index based on four factors(FIB-4), AST to platelet ratio index(APRI) and AST/ALT ratio(AAR) calculated as serum tests were investigated by analyzing ROC curve. As a result, using FIB-4 and APRI rather than AAR is appropriate for evaluation of liver fibrosis. And using APRI to predict significant Fibrosis(F2) and FIB-4 is considered useful for predicting cirrhosis(F4). By applying the advantages of the serum based liver fibrosis marker, which are convenient and repeatable, liver fibrosis follow-up term can be reduced, and furthermore, the prevalence of liver cirrhosis and hepatocellular carcinoma(HCC) can be reduced.

• Tuberculosis and Respiratory Diseases
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• v.69 no.3
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• pp.184-190
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• 2010

Background: The purpose of this study was to determine the prognostic significance of chest computed tomographic (CT) parameters in acute submassive pulmonary embolism (PE). Methods: Between January 2006 and December 2009, 268 consecutive patients with acute submassive PE that was confirmed by chest CT with pulmonary angiography in emergency room were studied. One experienced radiologist measured CT parameters and judged the presence of right ventricular dysfunction. CT parameters were analyzed to determine their ability to predict a major adverse event (MAE). Results: There were 220 patients included and 61 (27.7%) had MAE. Left ventricular and right ventricular maximum minor axis ($36.4{\pm}8.0$ vs. $41.7{\pm}7.4$, p<0.01; $45.7{\pm}9.4$ vs. $41.5{\pm}7.6$, p<0.01), superior vena cava diameter ($19.2{\pm}3.4$ vs. $18.0{\pm}3.4$, p=0.02), azygos vein diameter ($10.0{\pm}2.2$ vs. $9.2{\pm}2.3$, p=0.02), septal displacement (19 vs. 18, p<0.01) were significantly higher in MAE group than in no MAE group. Patients with MAE had high right ventricular/left ventricular dimension ratio (RV/LV ratio) compared to patients without MAE ($1.34{\pm}0.48$ vs. $1.03{\pm}0.28$, p<0.01). The most useful cut-off value of RV/LV ratio for MAE was 1.3 and the area under the curve was 0.71 (0.62~0.79). Conclusion: RV/LV ratio on chest CT was a significant predictor of submassive PE related shock, intubation, in-hospital mortality, thrombolysis, thrombectomy within 30 days.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.3
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• pp.313-319
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• 2017

Cylindrical shells are often used in ship structures at deck plating with a camber, side shell plating at fore and aft parts, and bilge structure part. It has been believed that such curved shells can be modelled fundamentally by a part of a cylinder under axial compression. From the estimations with the usage of cylinder models, it is known that, in general, curvature increases the buckling strength of a curved shell subjected to axial compression, and that curvature is also expected to increase the ultimate strength. We conduct series of elasto-plastic large deflection analyses in order to clarify the fundamentals in buckling and plastic collapse behaviour of cylindrical shells under axial compression. From the numerical results, we derive design formula for predicting the ultimate strength of cylindrical shell, based on a series of the nonlinear finite element calculations for all edges, simply supporting plating, varying the slenderness ratio, curvature and aspect ratio, as well as the following design formulae for predicting the ultimate strength of cylindrical shell. From a number of analysis results, fitting curve can be developed to use parameter of slenderness ratio with implementation of the method of least squares. The accuracy of design formulae for evaluating ultimate strength has been confirmed by comparing the calculated results with the FE-analysis results and it has a good agreement to predict their ultimate strength.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2037-2041
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• 2015

Background: Relationships between poor prognosis of ovarian malignancies and changes in complete blood count parameters have been proposed previously. In this work, we aimed to evaluate clinicopathologic features in adolescents with adnexal masses and sought to establish any predictive value of the platelet to lymphocyte ratio (PLR) in diagnosis. Materials and Methods: This retrospective study was conducted on 196 adolescent females with adnexal masses. Three groups were constituted with respect to clinical or histopathology results: group 1, non-neoplastic patients (n:65); group 2, neoplastic patients (n:68); and group 3 expectantly managed patients (n:63). The main parameters recorded from the hospital database and patient files were age, body mass index (BMI), chief symptoms, diameter of the mass (DOM), tumor marker levels, complete blood count values including absolute neutrophil, lymphocyte, and platelet counts, mean platelet volume, platelet distribution width, and platecrit, surgical features, and postoperative histopathology results. Results: The expectantly managed patients were younger than the other groups (p=0.007). The mean body mass index (BMI) was higher in the neoplastic group (p=0.016). Preoperative DOM, CA125, mean platelet volume and PLR were statistically significantly different between the groups (p<0.05). ROC curve analysis demonstrated that increased PLR (AUC, 0.609; p=0.011) and BMI (AUC, 0.611; p=0.011) may be discriminative factors in predicting ovarian neoplasms in adolescents preoperatively. When the cut-off point for the PLR level was set to 140, the sensitivity and specificity levels were found to be 65.7% and 57.6%, respectively. Conclusions: We suggest that beside a careful preoperative evaluation including clinical characteristics, ultrasonographic features and tumor markers, PLR may predict ovarian neoplasms in adolescents.

• Korean Journal of Remote Sensing
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• v.36 no.1
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• pp.67-81
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• 2020

The rapid climatic changes being caused by global warming are resulting in abnormal weather conditions worldwide, which in some regions have increased the frequency of landslides. This study was aimed to analyze and compare the landslide susceptibility using the Frequency Ratio (FR), Statistical Index, Weight of Evidence, Certainty Factor, and Index of Entropy (IoE) at Woomyeon Mountain in South Korea. Through the construction of a landslide inventory map, 164 landslide locations in total were found, of which 50 (30%) were reserved to validate the model after 114 (70%) had been chosen at random for model training. The sixteen landslide conditioning factors related to topography, hydrology, pedology, and forestry factors were considered. The results were evaluated and compared using relative operating characteristic curve and the statistical indexes. From the analysis, it was shown that the FR and IoE models were better than the other models. The FR model, with a prediction rate of 0.805, performed slightly better than the IoE model with a prediction rate of 0.798. These models had the same sensitivity values of 0.940. The IoE model gave a specific value of 0.329 and an accuracy value of 0.710, which outperforms the FR model which gave 0.276 and 0.680, respectively, to predict the spatial landslide in the study area. The generated landslide susceptibility maps can be useful for disaster and land use planning.

• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.29-41
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• 1994

High temperature tensiles tests, steady state creep tests, internal stress tests and creep rupture tests using Al 7075 alloy were performed over the temperature range of 9$0^{\circ}C$~50$0^{\circ}C$ and stress range of 0.64~17.2(kgf/$\textrm{mm}^2$) in order to investigate the creep behavior and predict creep rupture life From the apparent activation energy Qc and the applied stress exponent n measured, at the temperature range of 9$0^{\circ}C$~l2$0^{\circ}C$, the creep deformation seemed to be controlled by cross slip. On the other hand at the temperature of 20$0^{\circ}C$~23$0^{\circ}C$ the creep deformation seemed to be controlled by dislocation climb but at 47$0^{\circ}C$~50$0^{\circ}C$, by diffusion creep. And the rupture life(t$_{f}$) might be represented by anthermal process attributed to the difference of the applied stress dependence of Internal stress and the ratio of the Internal stress to the applied stress, the thermal activated process attributied to the temperature dependence of the internal stress. Also the ratio between stress dependence of primary creep rate and that of minimum creep rate was measured 0.46, the minimum creep rate is expected to be appromately obtained from master creep curve including the relationship primary creep rate and minumum creep rate. Finally the relationship new rupture parameter and logarithmic stress was represented with including the ratio between the dependence of primary creep rate and that of minimum creep rate, using the new rupture parameter the rupture life predition is exactly expected.d.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.307-313
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• 2021

The purpose of this study was to analyze the risk factors for uterine myoma diagnosed by ultrasonography in Korea women and to evaluate the risk. Among the patients who visited the outpatient department of obstetrics and gynecology at I hospital in Busin between January 2019 and March 2021 for the purpose of examination, 98 patients in the experimental group diagnosed with uterine myoma and 163 patients in the normal control group without other diseases were retrospectively conducted. Among the general characteristics of the subjects, age, body mass index, parity, and menopause showed significant differences between the myoma group and the normal control group. ROC(receiver operating characteristic) curve analysis and logistic regression analysis were performed to obtain the cut off value and odds ratio that can predict the occurrence of uterine myoma. The cut off value for the prediction of uterine myoma was determined to be 30 years old and a body mass index of 23 kg/m². After that adjusting for menopause, non menopausal cases with a body mass index of 23 kg/m² and over 39 years of age had the highest odds ratio of 6.04. Therefore, premenopausal women over 40 years of age require regular checkups and thorough weight management. This study was conducted with a small number of subjects. Therefore, there is a limit to generalizing to all Korean women. However, based on this study if a large scale prospective study considering various variables is made, it can play a role as a predictive marker in early detection of uterine myoma.