• Korean Journal of Radiology
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• v.22 no.9
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• pp.1514-1524
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• 2021

Objective: To develop a radiomics risk score based on dynamic contrast-enhanced (DCE) MRI for prognosis prediction in patients with glioblastoma. Materials and Methods: One hundred and fifty patients (92 male [61.3%]; mean age ± standard deviation, 60.5 ± 13.5 years) with glioblastoma who underwent preoperative MRI were enrolled in the study. Six hundred and forty-two radiomic features were extracted from volume transfer constant (K^trans), fractional volume of vascular plasma space (V_p), and fractional volume of extravascular extracellular space (V_e) maps of DCE MRI, wherein the regions of interest were based on both T1-weighted contrast-enhancing areas and non-enhancing T2 hyperintense areas. Using feature selection algorithms, salient radiomic features were selected from the 642 features. Next, a radiomics risk score was developed using a weighted combination of the selected features in the discovery set (n = 105); the risk score was validated in the validation set (n = 45) by investigating the difference in prognosis between the "radiomics risk score" groups. Finally, multivariable Cox regression analysis for progression-free survival was performed using the radiomics risk score and clinical variables as covariates. Results: 16 radiomic features obtained from non-enhancing T2 hyperintense areas were selected among the 642 features identified. The radiomics risk score was used to stratify high- and low-risk groups in both the discovery and validation sets (both p < 0.001 by the log-rank test). The radiomics risk score and presence of isocitrate dehydrogenase (IDH) mutation showed independent associations with progression-free survival in opposite directions (hazard ratio, 3.56; p = 0.004 and hazard ratio, 0.34; p = 0.022, respectively). Conclusion: We developed and validated the "radiomics risk score" from the features of DCE MRI based on non-enhancing T2 hyperintense areas for risk stratification of patients with glioblastoma. It was associated with progression-free survival independently of IDH mutation status.

• Korean Journal of Radiology
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• v.22 no.8
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• pp.1323-1331
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• 2021

Objective: To identify the association between renal tumor complexity and pathologic renal sinus invasion (RSI) and evaluate the usefulness of computed tomography tumor features for predicting RSI in patients with renal cell carcinoma (RCC). Materials and Methods: This retrospective study included 276 consecutive patients who underwent radical nephrectomy for RCC with a size of ≤ 7 cm between January 2014 and October 2017. Tumor complexity and anatomical renal sinus involvement were evaluated using two standardized scoring systems: the radius (R), exophytic or endophytic (E), nearness to collecting system or sinus (N), anterior or posterior (A), and location relative to polar lines (RENAL) nephrometry and preoperative aspects and dimensions used for anatomical classification (PADUA) system. CT-based tumor features, including shape, enhancement pattern, margin at the interface of the renal sinus (smooth vs. non-smooth), and finger-like projection of the mass, were also assessed by two independent radiologists. Univariable and multivariable logistic regression analyses were performed to identify significant predictors of RSI. The positive predictive value, negative predictive value (NPV), accuracy of anatomical renal sinus involvement, and tumor features were evaluated. Results: Eighty-one of 276 patients (29.3%) demonstrated RSI. Among highly complex tumors (RENAL or PADUA score ≥ 10), the frequencies of RSI were 42.4% (39/92) and 38.0% (71/187) using RENAL and PADUA scores, respectively. Multivariable analysis showed that a non-smooth margin and the presence of a finger-like projection were significant predictors of RSI. Anatomical renal sinus involvement showed high NPVs (91.7% and 95.2%) but low accuracy (40.2% and 43.1%) for RSI, whereas the presence of a non-smooth margin or finger-like projection demonstrated comparably high NPVs (90.0% and 91.3% for both readers) and improved accuracy (67.0% and 73.9%, respectively). Conclusion: A non-smooth margin or the presence of a finger-like projection can be used as a preoperative CT-based tumor feature for predicting RSI in patients with RCC.

• Advanced Industrial SCIence
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• v.3 no.2
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• pp.8-16
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• 2024

This paper shows the system of drug classification, the goal of this is to foretell the apt drug for the patients based on their demographic and physiological traits. The dataset consists of various attributes like Age, Sex, BP (Blood Pressure), Cholesterol Level, and Na_to_K (Sodium to Potassium ratio), with the objective to determine the kind of drug being given. The models used in this paper are K-Nearest Neighbors (KNN), Logistic Regression and Random Forest. Further to fine-tune hyper parameters using 5-fold cross-validation, GridSearchCV was used and each model was trained and tested on the dataset. To assess the performance of each model both with and without hyper parameter tuning evaluation metrics like accuracy, confusion matrices, and classification reports were used and the accuracy of the models without GridSearchCV was 0.7, 0.875, 0.975 and with GridSearchCV was 0.75, 1.0, 0.975. According to GridSearchCV Logistic Regression is the most suitable model for drug classification among the three-model used followed by the K-Nearest Neighbors. Also, Na_to_K is an essential feature in predicting the outcome.

• Journal of The Korean Association For Science Education
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• v.27 no.7
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• pp.547-558
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• 2007

The purpose of this study is to compare inquiry activities in science textbooks' physics contents for Korean secondary schools with those of Singapore in order to provide a reference for further improvement of inquiry activities in Korean science textbooks. We analyzed inquiry activities using the framework of Millar et al.(1998) and Chinn & Malhotra (2002). The results of this study are as follows: There are differences between Korean and Singaporean inquiry activities in the area of 'learning objectives', 'students' thinking activities' and 'degree of openness'. In the area of 'learning objectives', the Korean textbooks have more activities associated with the learning of science content than those in Singaporean, whereas the Singaporean textbooks have more activities associated with the processes of scientific inquiry than in Korean textbooks. In the area of 'students' thinking activities', the Singaporean textbooks have activities like 'test a prediction', which Korean textbooks lack. The 'degree of openness' is higher in Singaporean textbooks than in Korean textbooks. And some differences in the area of 'authentic scientific inquiry' between Korean and Singaporean textbooks were also found. While the Korean textbooks do not have any activities associated with 'generating research questions', the Singaporean ones feature such activities. In the area of 'designing studies', the Singaporean textbooks have activities corresponding to 'selecting variables' and 'controlling variables', while the Korean ones never have such activities. The results of this study imply that it is necessary to balance inquiry activities in the area of 'learning objectives', 'students' thinking activities' and 'degree of openness', and to present activities close to authentic scientific inquiry in inquiry activities in textbooks.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.181-188
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• 2009

The macro tidal flat of the Gochanggun Myongsasipri, located on the southwestern coast of Korea, is studied in terms of seasonal variations of surface sediment and sedimentary environment. Surface sediments of 45 sites in the winter (February) and the summer (August) are sampled across three survey lines (15 sites in each survey line), respectively. The tidal flat of open-coast Myongsasipri is mainly composed of fine to medium sand, the distribution of which shows a coast-parallel trend. Grain-size distribution has a bi-modal trend, and grain size in the winter is coarser than that in the summer. During the winter, the upper tidal flat is dominated by medium sand, while the lower tidal flat is dominated by find sand. Such a feature is attributed to wave-dominated sedimentation in the winter. The finer grains of the summer rather than that of the winter and relationship between texture parameters suggest that tidal energy plays an important role in tidal-flat sedimentation during the summer. This study represents an environmental change from wave-dominated conditions in the winter to tide-dominated conditions in the summer as a result of the seasonal variation in the intensity of onshore-directed winds and waves in the Myongsasipri tidal flat.

• Journal of the Daesoon Academy of Sciences
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• v.47
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• pp.105-138
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• 2023

The purpose of this study is to examine the significance of various figures in The Canonical Scripture and their contents. The Canonical Scripture (jeon-gyeong 典經) is a record of the beliefs and deeds of Kang Jeungsan, composed through the memories of the followers of Kang Jeungsan who followed the words of The Canonical Scripture. In other words, The Canonical Scripture is understood as the scripture of Daesoon Jinrihoe that contains the religious deeds and teachings of Kang Jeungsan. It is divided into seven parts and 17 chapters. Those seven parts, some of which contain more than one chapter, are as follows: Acts, Reordering Works, Progress of the Order, Dharma, Authority and Foreknowledge, Saving Lives, and Prophetic Elucidations. In particular, The Canonical Scripture records the deeds of historical figures from both China and Korea, and this prominently includes the life history of Kang Jeungsan, and this is an especially pronounced feature of the sections Acts, Progress of the Order, and Prophetic Elucidations. In addition, each chapter describes the teachings and faith-inspiring acts of Kang Jeungsan and presents the gist of the Daesoon Thought while referring to the lives and actions of various historical figures. In this paper, introductions to the figures that appear in each section are provided to help readers better understand the contents of The Canonical Scripture. Therefore, this study focuses on the major figures introduced in The Canonical Scripture in connection with the religious values of Daesoon Thought. Through this, a contribution is made to the academic development of Daesoon Thought by specifically exploring and examining the contents of the figures who appear in The Canonical Scripture. This is a surprisingly underdeveloped area of study in Daesoon Thought.

• Sim-seong Yeon-gu
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• v.31 no.1
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• pp.41-94
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• 2016

A Korean fairy tale "The uproot of an archenemy in the underworld" is discussed and interpreted from the perspective of analytical psychology. The essence of the story is as follows; When the three princesses were kidnapped by an archenemy in the underworld, a warrior appeared to save the princesses. He went to the underworld and killed the archenemy with the princesses help. When they tried to come back to the castle, he had difficulties because king's soldiers betrayed him. But a old wise man and a flying horse helped him to come back to the castle. He killed the soldiers that betrayed him and married one of the princesses and got the wealth from the underworld. The kingdom could be prosperous and peace because of the marriage. The psychological meaning of the three princesses were taken by the archenemy is that the archetypal shadow appeared from the unconscious and grasped a part of consciousness and repressed it in unconsciousness. This status could be called the lost of soul. So the warrior ego went through an unconscious trip, saving his anima from the archetypal shadow, and taking her back to consciousness and renewing the collective consciousness. The ego's trip is the individuation process like Shaman in primitive society. This fairy tale has hero motif. It reveals the feature of archetypal shadow. It also shows us man can make conscious with cautious attitude in the individuation process.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.1-15
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• 2024

The construction of smart communities is a new method and important measure to ensure the security of residential areas. In order to solve the problem of low accuracy in face recognition caused by distorting facial features due to monitoring camera angles and other external factors, this paper proposes the following optimization strategies in designing a face recognition network: firstly, a global graph convolution module is designed to encode facial features as graph nodes, and a multi-scale feature enhancement residual module is designed to extract facial keypoint features in conjunction with the global graph convolution module. Secondly, after obtaining facial keypoints, they are constructed as a directed graph structure, and graph attention mechanisms are used to enhance the representation power of graph features. Finally, tensor computations are performed on the graph features of two faces, and the aggregated features are extracted and discriminated by a fully connected layer to determine whether the individuals' identities are the same. Through various experimental tests, the network designed in this paper achieves an AUC index of 85.65% for facial keypoint localization on the 300W public dataset and 88.92% on a self-built dataset. In terms of face recognition accuracy, the proposed network achieves an accuracy of 83.41% on the IBUG public dataset and 96.74% on a self-built dataset. Experimental results demonstrate that the network designed in this paper exhibits high detection and recognition accuracy for faces in surveillance videos.

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.273-285
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• 2024

With the active utilization of Online Judge (OJ) systems in the field of education, various studies utilizing learner data have emerged. This research proposes a problem recommendation based on a user-based collaborative filtering approach with learner data to support learners in their problem selection. Assistance in learners' problem selection within the OJ system is crucial for enhancing the effectiveness of education as it impacts the learning path. To achieve this, this system identifies learners with similar problem-solving tendencies and utilizes their problem-solving history. The proposed technique has been implemented on an OJ site in the fields of algorithms and programming, operated by the Chungbuk Education Research and Information Institute. The technique's service utility and usability were assessed through expert reviews using the Delphi technique. Additionally, it was piloted with site users, and an analysis of the ratio of correctness revealed approximately a 16% higher submission rate for recommended problems compared to the overall submissions. A survey targeting users who used the recommended problems yielded a 78% response rate, with the majority indicating that the feature was helpful. However, low selection rates of recommended problems and low response rates within the subset of users who used recommended problems highlight the need for future research focusing on improving accessibility, enhancing user feedback collection, and diversifying learner data analysis.

• Composites Research
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• v.37 no.1
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• pp.7-14
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• 2024

Due to the structural characteristic of a double roller, the double roller can have various deformation behaviors depending on a gap block design, even if dimensions and loading conditions for the double roller are the same. Based on this feature, we propose a strategy for designing the gap block of the carbon-fiber reinforced plastic (CFRP) double roller to minimize defects (e.g., sagging and wrinkling), which can be raised during the product conveying process, with the pursue of the lightweight design. In the suggested strategy, analysis cases are first selected by considering main design parameters and engineering tolerances of the gap block, and then deformation behaviors of these selected cases are extracted using the finite element method (FEM). Here, to obtain the optimal gap block parameters that satisfy the purpose of this study, deformation deviations in the contact area are calculated and compared using the extracted deformation behaviors. Note that the contact area in this work is located between the product and the roller. As a result, through the design method of the gap block proposed in this work, it is possible to construct the CFRP double roller that can significantly decrease the defects without changing the overall sizes of the roller. A detailed method is suggested herein, and the results are evaluated in a numerical way.