• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.175-177
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• 2020

In multi-channel wireless sensor networks, optimizing data aggregation delay without any channels and timeslots conflicts has been concerned these days. The aggregation delay can be reduced by using different aggregation tree construction methods or scheduling in different methods in bottom-up or top-down manners. In this paper, we propose a new way of constructing aggregation tree purposing to decrease the total aggregation delay. The result shows that our proposed scheme can improve up to 64% comparing with state-of-the-art schemes.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.65.2-65.2
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• 2016

We present a new database of our two-dimensional bulge-disk decompositions for 14,482 galaxies drawn from SDSS DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in g and r bands by utilizing the GALFIT software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique. The g-r colors of bulges derived are almost constantly red regardless of bulge size except for the bulges in the low bulge-to-total ratio galaxies (approximately $B/T_r{\leq}0.3$). Bulges exhibit similar scaling relations to those followed by elliptical galaxies, but the bulges in galaxies with lower bulge-to-total ratios clearly show a gradually larger departure in slope from the elliptical galaxy sequence. The scatters around the scaling relations are also larger for the bulges in galaxies with lower bulge-to-total ratios. Both the departure in slopes and larger scatters are likely originated from the presence of young stars. While bulges seem largely similar in optical properties to elliptical galaxies, they do show clear and systematic departures as a function of bulge-to-total ratio. The stellar properties and perhaps associated formation processes of bulges seem much more diverse than those of elliptical galaxies.

• PNF and Movement
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• v.19 no.1
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• pp.9-17
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• 2021

Purpose: This study aims to verify the effectiveness of sit-to-stand training with visual feedback to improve balance ability and knee extensor strength of total knee replacement patients. Methods: In this study, 15 patients with total knee replacement participated in this study. Subjects were assigned to two groups: a feedback group (experimental group)(n = 8) and a control group (n = 7). They all received 30 min of continuous passive motion (CPM) and sit-to-stand training for 15 min five times per week for two weeks. Knee extensor and balance ability were measured. Knee extensor was measured by Biodex system 3; balance ability was measured by Balancia software. Results: After the intervention, there was a significant difference in the strengthening of the knee extensor muscles in the feedback group, area 95%, weight distribution of the affected side, and the sit-to-stand test repeated five times (p < 0.05). Conclusion: The results of this study showed that sit-to-stand training with visual feedback was more effective in increasing knee extensor muscle strength and balance ability than the sit-to-stand training without visual feedback. Therefore, in order to improve the knee extensor muscle and the balance of total knee replacement patients, it is necessary to consider providing visual feedback during sit-to-stand training.

• Structural Engineering and Mechanics
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• v.91 no.3
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• pp.251-262
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• 2024

Numerical modeling using the finite element method (FEM) offers crucial insights into the mechanical behavior of prostheses, including stress and strain distribution, load transfer, and stress intensity factors. Analyzing cracking in PMMA surgical cement (polymethylmethacrylate) for total hip prostheses (THP) is essential for understanding the loosening phenomenon, as the rupture of orthopedic cement is a primary cause. By understanding various failure mechanisms, significant advancements in cemented total prostheses can be achieved. This study performed a numerical analysis using a 3D FEM model to evaluate stress levels in different THP models, aiming to model damage in the orthopedic cement used in total hip arthroplasty. Utilizing ABAQUS software, FEM, and XFEM, the damage in three types of THPs-Charnley (CMK3), Osteal (BM3), and THOMPSON was modeled under stumbling loading conditions. XFEM allowed for the consideration of crack propagation between the cement and bone, while the GEARING criterion employed a user-defined field subroutine to model damage parameters. The study's findings can contribute to improving implant fixation techniques and preventing postoperative complications in orthopedic surgery.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.57-63
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• 2012

Software release planning model of software product lines was formulated as a precedence-constrained multiple 0-1 knapsack problem. The purpose of the model was to maximize the total profit of an entire set of selected features in a software product line over a multi-release planning horizon. The solution approach is a dynamic programming procedure. Feasible solutions at each stage in dynamic programming are determined by using backward dynamic programming approach while dynamic programming for multi-release planning is forward approach. The pre-processing procedure with a heuristic and reduction algorithm was applied to the single-release problems corresponding to each stage in multi-release dynamic programming in order to reduce the problem size. The heuristic algorithm is used to find a lower bound to the problem. The reduction method makes use of the lower bound to fix a number of variables at either 0 or 1. Then the reduced problem can be solved easily by the dynamic programming approaches. These procedures keep on going until release t = T. A numerical example was developed to show how well the solution procedures in this research works on it. Future work in this area could include the development of a heuristic to obtain lower bounds closer to the optimal solution to the model in this article, as well as computational test of the heuristic algorithm and the exact solution approach developed in this paper. Also, more constraints reflecting the characteristics of software product lines may be added to the model. For instance, other resources such as multiple teams, each developing one product or a platform in a software product line could be added to the model.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.301-313
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• 1999

Recently, the rabid development of information technology has brought enormous changes in education. Consolidation of communications and multimedia technologies are enabling the new educational paradigm such as distance learning and virtual education. Furthermore, many studies in the education engineering field report that teaching using multimedia technologies more enhances students' performance than the traditional instructor-teaching method. However, little research regarding the education using multimedia has been done in the MIS filed. None of multimedia-related studies could be found in the top-ranked MIS journals published in Korea for the last five years, and only a few studies were found even worldwide. In this regard, the purpose of this study is to investigate which features of multimedia software are most important to enhance the teaching results of students. From the previous research, we found out the specific features of the educational multimedia software which are considered to affect the students'performance, and defined the research variables related to those educational software features. And, based on the constructivism and motivation theory of the education engineering field a theoretical research model and research hypotheses were developed. Perceived usefulness of the class and a student's perceived interests in the class were used as surrogate variables to measure teaching performance. Total 277 students participated separately in one of the two multimedia classes which have continued for three weeks. One was C programming language class and the other was multimedia CD-title development class. Each student listened for the multimedia session of the class using multimedia software and, at the end of the multimedia session, answered the survey questionnaire. The results of the study show that motivation to the class and the contents of education were statistically significant to the students'performance in the class. That implies, not only in the traditional instructor-teaching method but also in the multimedia class, that the contents of education itself and student's motivation to the class are most important to raise instructional results.

• Journal of Information Processing Systems
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• v.7 no.2
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• pp.363-384
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• 2011

As the complexity of software is increasing, generating an effective test data has become a necessity. This necessity has increased the demand for techniques that can generate test data effectively. This paper proposes a test data generation technique based on adequacy based testing criteria. Adequacy based testing criteria uses the concept of mutation analysis to check the adequacy of test data. In general, mutation analysis is applied after the test data is generated. But, in this work, we propose a technique that applies mutation analysis at the time of test data generation only, rather than applying it after the test data has been generated. This saves significant amount of time (required to generate adequate test cases) as compared to the latter case as the total time in the latter case is the sum of the time to generate test data and the time to apply mutation analysis to the generated test data. We also use genetic algorithms that explore the complete domain of the program to provide near-global optimum solution. In this paper, we first define and explain the proposed technique. Then we validate the proposed technique using ten real time programs. The proposed technique is compared with path testing technique (that use reliability based testing criteria) for these ten programs. The results show that the adequacy based proposed technique is better than the reliability based path testing technique and there is a significant reduce in number of generated test cases and time taken to generate test cases.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.203-215
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• 2014

Although many studies about start-up existed, It is almost never shown study about ICT convergence start-up enterprise. This study tries to analyze success factor to start-up enterprise in rapidly growing ICT convergence area. Based on 10 entrepreneurial success cases, We figure out the total 29 units success factors utilizing ERIS model. We classify ICT commercialization with 4 types which are software-R&D centric, software marketing centric, software plus hardware R&D centric, software plus hardware marketing centric. Among success factors the most success factor is related entrepreneur;s ability and include major and professional knowledge about ICT's filed, insight through sensitivity about technical paradigm etc. It was derived the success factors indicated in the course of commercialization of ICT Covergence Unlike other forms of the existing start-up entrepreneurs and contributed to typified in four forms startups for ICT Covergence start-up entrepreneurs.

• Korean Journal of Remote Sensing
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• v.35 no.6_4
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• pp.1341-1350
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• 2019

This research deals with algorithm for forest fire severity classification using multi-temporal KOMPSAT-3A image to mapping forest fire areas. The recent satellite of the KOMPSAT series, KOMPSAT-3A, demonstrates high resolution and multi-spectral imagery with infrared and high resolution electro-optical bands. However, there is a lack of research to classify forest fire severity using KOMPSAT-3A. Therefore, the purpose of this study is to analyze forest fire severity using KOMPSAT-3A images. In addition, this research used pre-fire and post-fire Sentinel-2 with differenced Normalized Burn Ratio (dNBR) to taking for burn severity distribution map. To test the effectiveness of the proposed procedure on April 4, 2019, Gangneung wildfires were considered as a case study. This research used the probability density function for the classification of forest fire damage severity based on R software, a free software environment of statistical computing and graphics. The burn severities were estimated by changing NDVI before and after forest fire. Furthermore, standard deviation of probability density function was used to calculate the size of each class interval. A total of five distribution of forest fire severity were effectively classified.

• Asia pacific journal of information systems
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• v.10 no.1
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• pp.37-59
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• 2000

Recently, the rapid development of information technology has brought enormous changes in education. Consolidation of communications and multimedia technologies are enabling the new educational paradigm such as distance learning and virtual education. Furthermore, many studies in the education engineering field report that teaching using multimedia technologies more enhances students' performance than the traditional instructor-teaching method. However, little research regarding the education using multimedia has been done in the MIS filed. None of multimedia-related studies could be found in the top-ranked MIS journals published in Korea for the last five years, and only a few studies were found even worldwide. In this regard, the purpose of this study is to investigate which features of multimedia software are most important to enhance the teaching results of students, From the previous research, we found out the specific features of the educational multimedia software which are considered to affect the students' performance, and defined the research variables related to those educational software features, And, based on the constructivism and motivation theory of the education engineering field, a theoretical research model and research hypotheses were developed. Perceived usefulness of the class and a student's perceived interests in the class were used as surrogate variables to measure teaching performance. Total 277 students participated separately in one of the two multimedia classes which have continued for three weeks. One was C programming language class and the other was multimedia CD-title development class. Each student listened for the multimedia session of the class using multimedia software and, at the end of the multimedia session, answered the survey questionnaire, The results of the study show that motivation to the class and the contents of education were statistically significant to the students' performance in the class. That implies, not only in the traditional instructor-teaching method but also in the multimedia class, that the contents of education itself and student's motivation to the class are most important to raise instructional results.