• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.239-248
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• 2020

Exact rock classification helps suitable support patterns to be installed. Face mapping is usually conducted to classify the rock mass using RMR (Rock Mass Ration) or Q values. There have been several attempts to predict the grade of rock mass using mechanical data of jumbo drills or probe drills and photographs of excavation surfaces by using deep learning. However, they took long time, or had a limitation that it is impossible to grasp the rock grade in ahead of the tunnel surface. In this study, a method to predict the Q value ahead of excavation surface is developed using recurrent neural network (RNN) technique and it is compared with the Q values from face mapping for verification. Among Q values from over 4,600 tunnel faces, 70% of data was used for learning, and the rests were used for verification. Repeated learnings were performed in different number of learning and number of previous excavation surfaces utilized for learning. The coincidence between the predicted and actual Q values was compared with the root mean square error (RMSE). RMSE value from 600 times repeated learning with 2 prior excavation faces gives a lowest values. The results from this study can vary with the input data sets, the results can help to understand how the past ground conditions affect the future ground conditions and to predict the Q value ahead of the tunnel excavation face.

• Korean Journal of Environment and Ecology
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• v.36 no.3
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• pp.350-357
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• 2022

A national park is a place to conserve natural resources and visitors to experience nature, and thus, it is necessary to identify the noise distribution characteristic in the national park and preserve and restore the soundscape. However, most national parks in Korea are exposed to noise, leading to negative perceptions of the national park's soundscape and affecting the ecosystem. Many national parks in other countries have investigated the ecosystem impacts caused by noise and have performed various management to reduce the noise. However, in Korea, there is still a lack of awareness of the effect on the ecosystem, overlooking the need for soundscape management. Therefore, in this study, we developed a noise map of Mudeungsan National Park to investigate the quantitative impact of noise on visitors and the ecosystem. Also, we measured the trail's soundscape to describe a sound grade classification, and the soundscape of main spots in the park was recorded for a year and then analyzed. Finally, the sound resource distribution map was described, which can be used as preliminary data to determine the national park's sound distribution characteristics and manage the soundscape.

• The Mathematical Education
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• v.63 no.1
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• pp.19-33
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• 2024

This study investigates longitudinal patterns in middle school students' mathematics interest and achievement using panel data from the 4th to 6th year of the Gyeonggi Education Panel Study. Results from the multivariate growth mixture model confirmed the existence of heterogeneous characteristics in the longitudinal trajectory of students' mathematics interest and achievement. Students were classified into four latent classes: a low-level class with weak interest and achievement, a high-level class with strong interest and achievement, a middlelevel-increasing class where interest and achievement rise with grade, and a middle-level-decreasing class where interest and achievement decline with grade. Each class exhibited distinct patterns in the change of interest and achievement. Moreover, an examination of the correlation between intercepts and slopes in the multivariate growth mixture model reveals a positive association between interest and achievement with respect to their initial values and growth rates. We further explore predictive variables influencing latent class assignment. The results indicated that students' educational ambition and time spent on private education positively affect mathematics interest and achievement, and the influence of prior learning varies based on its intensity. The perceived instruction method significantly impacts latent class assignment: teacher-centered instruction increases the likelihood of belonging to higher-level classes, while learner-centered instruction increases the likelihood of belonging to lower-level classes. This study has significant implications as it presents a new method for analyzing the longitudinal patterns of students' characteristics in mathematics education through the application of the multivariate growth mixture model.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.23-29
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• 2005

The fancy veneer flooring board is high value-added wooden material. The classification of the flooring boards by the observation with the naked eye causes color difference among fancy veneers. It turned out that this inaccuracy of color difference among fancy veneers increased in case of the identification by metamerism or the flooring construction. Therefore, this study was performed to classify fancy veneers produced from 3 species such as Tilia sp., Betula sp., and Acer sp. which were identified with the naked eye by Light and Dark grade, by using CIELAB. In addition, each specie's threshold on CIERGB was investigated and a range of hue, saturation and intensity by an application of HSI color model were studied. Intensity of the HIS color model could be the best value to be used when color, saturation and intensity of the HSI color model were used for the classification of the flooring board's color. In addition, it seemed that color range of all three criteria lied between $45^{\circ}$ and $55^{\circ}$. In the case of identification by threshold of RGB element, considering only specific color element value is unlikely to lead to accurate classification of fancy veneers of flooring board.

• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.46-64
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• 2019

Technical practice code, KGS GC101 2018, for explosion hazard area selection and distance calculation of gas facility was enacted and implemented from July 12, 2018. This code includes whole contents of IEC60079-10-1 2015 (Explosive atmospheres Part 10-1: Classification of areas - Explosive gas atmospheres), and clarifies the interpretation of ambiguous standards or adds guidelines for standards. KGS GC101 is a method for classifying explosion hazard place types: (1) Determination of leak grade (2) Determination of leakage hole size (3) Determination of leakage flow (4) Determination of dilution class (5) Determination of ventilation effectiveness, finally (6) Determination of danger place (7) Explosion The range of dangerous places can be estimated. In order to easily calculate this process, the program (KGS-HAC v1.14, C-2018-020632) composed by Visual Basic for Application (Excel) language was produced by Korea Gas Safety Corporation. We will discuss how to use codes and programs to select and set up explosion hazard zones for field users.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.1
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• pp.45-51
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• 1995

The incidence of metastatic bony lesion has been increased recently, with the advanced therapeutic modalities of malignant tumors. The purpose of this study was to evaluate the effectiveness of surgical treatment in impending or established pathologic fractures due to metastasis in extremity. From 1981 to 1992, thirty two patients who had established or impending pathologic fractures in extremity had been treated surgically. The locations of metastasis, were lower extremity in 24 cases(femsral head and neck;5, intertrochanteric;7, subtrochanteric;8, femoral shaft;4) and upper extremity in 8 cases(proximal humerus;2, humoral shaft;6). The method of surgery was excision of tumor mass and rigid internal fixation to allow immediate mobilization, except 2 cases of amputation. The results were analysed by two criteria. The first was the grade of performance status that was made by modification of Functional Classification of New York Heart Association. The second was the degree of pain relief. The performance status was improved at least one grade in all patients and the mean improvement was 1.7 grades. The satisfactory pain relief was achieved in 81% of patients. Postoperatively, most of the patients had only slight to moderate limitation of physical activities and they became comfortable at rest and ordinary activities. The solitary metastatic lesions showed better pain relief(92%) than multiple metastasis(75%). The curative surgery was done in 3 cases, and they showed more than 24 months of disease-free survival.

• Journal of Korean Public Health Nursing
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• v.30 no.1
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• pp.149-163
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• 2016

Purpose: The aim of this study was to assess the readability and suitability of printed educational materials related to metabolic syndrome in South Korea. Methods: Data were collected on 15 educational materials on metabolic syndrome from public health centers in Seoul. The 9 Graded Korean Vocabulary Classification and Korean version of SAM (Suitability Assessment of Materials) were used for the readability evaluation and the suitability evaluation respectively. Results: Overall average of the readability was 3.0th grade level. The percentage of 1st to 4th grade words was 79.4%. The printed educational materials on metabolic syndrome were written according to recommended reading levels. In suitability assessment, 2 out of 15 materials(13.3%) were scored as superior, 12 materials(80.0%) were scored as adequate and only 1 (6.7%) was scored as inadequate. The total average score of suitability was adequate. However, there are limitations in "summary and review" and "context is given first" due to limited writing pages. Conclusion: Readability and suitability of educational materials for metabolic syndrome were evaluated as adequate level. However, future health educational materials should be evaluated for readability via different factors including length of sentences, numbers of sentences, and structure of sentences. In addition, for easier understanding and motivation of readers, materials should use summary & review, context and proper interaction.

• Journal of Korean Neurosurgical Society
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• v.52 no.3
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• pp.204-209
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• 2012

Objective : The authors performed a retrospective study to assess the accuracy and clinical benefits of a navigation coupled with O-arm$^{(R)}$ system guided method in the thoracic and lumbar spines by comparing with a C-arm fluoroscopy-guided method. Methods : Under the navigation guidance, 106 pedicle screws inserted from T7 to S1 in 24 patients, and using the fluoroscopy guidance, 204 pedicle screws from T5 to S1 in 45 patients. The position of screws within the pedicle was classified into four groups, from grade 0 (no violation cortex) to 3 (more than 4 mm violation). The location of violated pedicle cortex was also assessed. Intra-operative parameters including time required for preparation of screwing procedure, times for screwing and the number of X-ray shot were assessed in each group. Results : Grade 0 was observed in 186 (91.2%) screws of the fluoroscopy-guided group, and 99 (93.4%) of the navigation-guided group. Mean time required for inserting a screw was 3.8 minutes in the fluoroscopy-guided group, and 4.5 minutes in the navigation-guided group. Mean time required for preparation of screw placement was 4 minutes in the fluoroscopy-guided group, and 19 minutes in the navigation-guided group. The fluoroscopy-guided group required mean 8.9 times of X-ray shot for each screw placement. Conclusion : The screw placement under the navigation-guidance coupled with O-arm$^{(R)}$ system appears to be more accurate and safer than that under the fluoroscopy guidance, although the preparation and screwing time for the navigation-guided surgery is longer than that for the fluoroscopy-guided surgery.

• Proceedings of the Korean Society of Crop Science Conference
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• 2002.05a
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• pp.53-57
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• 2002

Quality evaluation must be more developed in order to offer the sufficient information for producer, distribution centers buyer, consumer. There are many parameters which influence the rice quality and cooked rice. It is difficult to evaluate the quality of rice and cooked rice by only some parameters. In the case of rice quality evaluation in Korea, physicochemical inspection is performed by examining the minimum and maximum limits of brown rice recovery, moisture content, damaged kernel, and colored kernel as inspection standard. Marketing standard of rice defines the limits of perfect, white core and belly, colored, damaged kernels, and broken rice, classifying into special, excellent, and normal grades. As a research direction for the development of rice quality evaluation, establishment as parts of technical field, must be further developed as follows : more detailed measure of characters, search of unknown taste-related components, creation and grade classification of quality evaluation factors at each management stages of treatment after harvesting, evaluation as food material as well as cooking rice, method development for simple evaluation and establishment of equation for palatability. In the side of policy, the following concerns must be conducted: price discrimination in conformity to rice cultivar and grade under the basis of qualify evaluation method developed, fixation of head rice branding, and introduction of low temperature circulation.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1187-1192
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• 2014

Background: To correlate breast cancer subtypes with prognostic factors, microvessel density (MVD), vascular endothelial growth factor (VEGF) expression and clinical features. Materials and Methods: One hundred cases of primary breast carcinoma were classified using biomarkers on tissue microarray as: luminal A [estrogen receptor (ER)+, HER2-, $Ki-67{\leq}14%$], luminal B [ER+, HER2+ or ER+, HER2-, Ki-67>14%], HER2, triple negative basal-like (TNB) [any basal cytokeratins (CKs, 5, 14, 17) and/or endothelial growth factor receptor (EGFR) expression], and TN without such markers [TNN, null], and assessed for p53, vimentin, VEGF and CD31 immunoperoxidase. Results: Of the 100 cases (mean age, 51 years; mean tumor size, 3.2cm; 56% with nodal metastasis; 89 invasive ductal carcinomas, not otherwise specified, 4 invasive lobular carcinomas, 3 metaplastic carcinomas, and 4 other types) there were 39 luminal A, 18 luminal B, 18 HER2, 15 TNB and 10 TNN. The positivities of basal-like markers in the basal-like subtype were 78.3% for CK5, 40% for CK14, 20% for CK17, 46.7% for EGFR. There was no significant difference in age distribution, tumor size, degree of tubular formation, pleomorphism, lymphovascular invasion, nodal metastasis, MVD, VEGF expression and survival among subgroups. TNs demonstrated significantly higher tumor grade, mitotic count, Ki-67 index, p53 and vimentin and decreased overall survival compared with nonTN. Conclusions: The distribution of breast cancer subtypes in this study was similar to other Asian countries with a high prevalence of TN. The high grade character of TN was confirmed and CK5 expression was found to be common in our basal-like subtype. No significant elevation of MVD or VEGF expression was apparent.