• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.147-156
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• 2009

We present a methodology for modeling and solving the transit frequency design problem with variable demand. The problem is described as a bi-level model based on a non-cooperative Stackelberg game. The upper-level operator problem is formulated as a non-linear optimization model to minimize net cost, which includes operating cost, travel cost and revenue, with fleet size and frequency constraints. The lower-level user problem is formulated as a capacity-constrained stochastic user equilibrium assignment model with variable demand, considering transfer delay between transit lines. An efficient algorithm is also presented for solving the proposed model. The upper-level model is solved by a gradient projection method, and the lower-level model is solved by an existing iterative balancing method. An application of the proposed model and algorithm is presented using a small test network. The results of this application show that the proposed algorithm converges well to an optimal point. The methodology of this study is expected to contribute to form a theoretical basis for diagnosing the problems of current transit systems and for improving its operational efficiency to increase the demand as well as the level of service.

• Land and Housing Review
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• v.3 no.4
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• pp.379-387
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• 2012

This paper analyzes characteristics and changing phenomenon of Chonsei & monthly rental real estate market based on a survey of participants. The frequency analysis, mean analysis, and cross-table analysis was utilized for this study, and a survey for 2,000 rental market participants was accomplished. The survey result of tenants and land-owners regarding the Chonsei market stability indicates the expansion of public housing supply is needed together with lowering of mortgage related restrictions. The major conclusions include that the expansion of public housing and rental supports for low-income families are needed, due to the population structural change and an aging society. In addition, survey result suggests the tenants require the expansion of public housing supply for the residence stability.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.499-506
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• 1995

A new numerical method estimated three dimensional shape of the internal surface of the stomach by analyzing the shading data of endoscopic image. First analyzed was the inherent instrumentational characteristics of the endoscope system, followed by the analysis of the stomach surface properties, both of which affected the imaging properties. We employed these prior informations to implement the iterative algorithm of shading analysis based on Hom's variational approach. The present algorithm was validated by performing simulation on a $256{\times}320$ image data chosen from original $512{\times}512$ image of the stomach surface model. The best 3-dimensional estimation of the surface was achieved with the Lagrangian multiplier, of 0.3, when the algorithm best converged showing minimal estimation error.

• Journal of the Korean earth science society
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• v.24 no.3
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• pp.117-127
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• 2003

This qualitative research investigated how to improve preservice and in-service teacher education programs through in-depth interviews with 10 exemplary science teachers. Data from interviews were used to analyze how the teachers perceived current situations of teacher education and what they suggested as an improvement plan. In terms of preservice teacher education, exemplary teachers argued that teacher education programs should (1) ensure the teacher education program's identity and goals, (2) provide preservice teachers with practical knowledge by translating theory into practice, and (3) secure faculty members who majored in science education. In light of in-service education, the teachers contended that (1) teachers should acknowledge the continuing processes of their own professional development, (2) the content and method of in-service training should incorporate teachers' practical needs in the classroom, and (3) the teaching community should implement a clinical supervision to improve their classroom practices. The central role of teacher (re)education in a successful classroom reform is also discussed.

• Korean Journal of Social Welfare
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• v.69 no.3
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• pp.165-191
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• 2017

The purpose of this study is to identify the major predictive factors of intention of drug users to use treatment services. The theoretical framework was used extended Behavioral Model of Health Services Use which integrates the Andersen model and the Theory of Planned Behavior. Thus, this study examined the effects of individual characteristics(predisposing, enabling, need factor) and attitude, subjective norm, perceived behavior control on drug users' intention to use treatment services. Factors with a statistically significant effect were as follows: from the individual characteristics - gender and past treatment experiences of the predisposing factors along with psychiatric diagnosis, anxiety and depression, and severity of drug abuse of need factors. From the Theory of Planned Behavior - subjective norm and perceived behavior control turned out to have impacts on their intention to use treatment services. The study emphasizes that a concern of women, increasing positive experiences of treatment, efforts to change the subjective norms and perceived behavior control of drug users to promote their determination to get treatment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1490-1499
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• 2022

Arrhythmia is a condition in which the heart has an irregular rhythm or abnormal heart rate, early diagnosis and management is very important because it can cause stroke, cardiac arrest, or even death. In this paper, we propose arrhythmia classification using hybrid combination model of CNN-BLSTM. For this purpose, the QRS features are detected from noise removed signal through pre-processing and a single bit segment was extracted. In this case, the GAN oversampling technique is applied to solve the data imbalance problem. It consisted of CNN layers to extract the patterns of the arrhythmia precisely, used them as the input of the BLSTM. The weights were learned through deep learning and the learning model was evaluated by the validation data. To evaluate the performance of the proposed method, classification accuracy, precision, recall, and F1-score were compared by using the MIT-BIH arrhythmia database. The achieved scores indicate 99.30%, 98.70%, 97.50%, 98.06% in terms of the accuracy, precision, recall, F1 score, respectively.

• Smart Media Journal
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• v.13 no.8
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• pp.39-48
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• 2024

Recently, various studies have emerged that utilize hyperspectral imaging for crop growth analysis and early disease diagnosis. However, the challenge of using numerous spectral bands or finding the optimal bands for crop area remains a difficult problem. In this paper, we propose a method of searching the optimized spectral band of crop area based on deep learning using the hyper-spectral image. The proposed method extracts RGB images within hyperspectral images to segment background and foreground area through a Vision Transformer-based Seformer. The segmented results project onto each band of gray-scale converted hyperspectral images. It determines the optimized spectral band of the crop area through the pixel comparison of the projected foreground and background area. The proposed method achieved foreground and background segmentation performance with an average accuracy of 98.47% and a mIoU of 96.48%. In addition, it was confirmed that the proposed method converges to the NIR regions closely related to the crop area compared to the mRMR method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.20-29
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• 2016

This study investigates the effect of the absorbent materials on the material properties(compressive strength and drying shrinkage) of natural hwangtoh mortar which is one of the traditional building material in Korea. The absorbent materials used are seaweed paste and Super-Absorbent Polymer(SAP). In addition to the absorbent materials, the initial sealed curing recommended by the standard specification of properties for Korean traditional building materials is also a main interest of this study. Based on the test results of 28 days compressive strength and converged drying shrinkage, it is confirmed that the initial sealed curing for 7 days is effective to reduce the drying shrinkage and to enhance the compressive strength. Thus, it is verified that the recommendation is reasonable and has positive effects on the properties of the mortar. Next, the test results show that the addition of absorbent materials into the mortar is also effective to the two properties depending on their absorption capacity. Thus, it is more effective to use SAP than the seaweed paste because of higher absorption capacity. However, both the initial sealed curing and keeping total water contents of the mortar are required to show this effectiveness. Lastly, the compressive strength is inversely proportional to the drying shrinkage. By using this relation, the reason of the increase of compressive strength due to the initial sealed curing or the addition of absorbent materials is quantitatively explained.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.236-247
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• 2020

This study was conducted with the aim of developing inspection tools to select and measure human resource figures and appropriate core competency of the educational goals pursued by S universities. Therefore, key competency factors were defined consistent with concept of talented figures and educational objectives of S universities, inspection tools were developed to measure core competences, and directions are presented for future education policies and curriculum compilation and securing data for rational operation. Based on key competency indicators, questions were developed in a self-reporting form that measures the consent level of the respondents by comprising seven areas of competence, 16 small areas (sub-capacity), and 46 questions. The main Test conducted an analysis of the questionnaires based on the survey results of 2,486 people to ensure the validity of the inspection by conducting a positive factor analysis and reliability analysis. The core competency diagnostic tool of S university is meaningful in this study which verifies the effectiveness of the curriculum and programs conducted at S university and as the first step for the rational operation of the core competency certification system to improve the competency appropriate for students.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.119-127
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• 2014

The application of sulfur polymer emulsion (SPE) as an acrylate substitute for semi-rigid pavement grout was evaluated, and the performance improvement by employing PVA fibers were also evaluated. The result indicated that the filling ratio of semi-rigid pavement material decreased as the fiber content increased, but it was measured to be 92~94% in every mixing condition, which satisfies the target performance, 90%. The maximum Marshall stability value of semi-rigid pavement material was measured to be 25.4 kN, which is about 4.7 times higher than the Korean Standard required for semi-rigid pavement material, 5.0 kN. The dynamic stability evaluation of semi-rigid pavement material indicated that the resistance to deformation from the wheel tracking test was improved by an SPE substitution, and in every mixing condition, the deformation converged to a constant value after 45 minutes with the same dynamic stability of 31,500 times/mm. The strain at the flexural failure was about 0.53%, which shows superior rigidity to asphalt pavements. The examination of abrasion resistance and impact resistance showed that the loss ratio was 9.8~6.0% in every mixing condition, which indicates a good abrasion resistance. Also, when fiber content ratio was 0.3%, the impact resistance was 2.82 times higher compared to plain (i.e., when fibers were not added). In the limited range of this study, an SPE substitution ratio of 30% was found to be an optimal level considering the mechanical and durability performance. In addition, it is thought that semi-rigid pavement material with superior performance could be manufactured if fiber content ratio up to 0.3% is applied depending on the purpose of use.