• 산업경영시스템학회지
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• 제37권1호
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• pp.1-8
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• 2014

This paper proposes an emotion classifier from EEG signals based on Bayes' theorem and a machine learning using a perceptron convergence algorithm. The emotions are represented on the valence and arousal dimensions. The fast Fourier transform spectrum analysis is used to extract features from the EEG signals. To verify the proposed method, we use an open database for emotion analysis using physiological signal (DEAP) and compare it with C-SVC which is one of the support vector machines. An emotion is defined as two-level class and three-level class in both valence and arousal dimensions. For the two-level class case, the accuracy of the valence and arousal estimation is 67% and 66%, respectively. For the three-level class case, the accuracy is 53% and 51%, respectively. Compared with the best case of the C-SVC, the proposed classifier gave 4% and 8% more accurate estimations of valence and arousal for the two-level class. In estimation of three-level class, the proposed method showed a similar performance to the best case of the C-SVC.

• 한국IT서비스학회지
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• 제15권4호
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• pp.153-174
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• 2016

On account of multiple causes, including prolonged global economic crisis, addressing environmental pollution and the advent of hyper-connected society, a new paradigm called 'sharing economy' has rapidly emerged. Many startups have attempted to build promising business model based on the sharing economy concept. Nevertheless, successful cases are still very rare in the global level, except for Uber and Airbnb cases. Therefore, this study analyzes necessary causes and sufficient causes for successful settlements in the market through a comparative case analysis on digital matching firms in the sharing economy businesses. For the case study, we compare five successful cases (Uber, Airbnb, Kickstarter, TaskRabbit and DogVacay), three failure cases (Homejoy, Ridejoy and Tuterspree) and a platform cooperativism case (Juno) in accordance with six value attributes of business model including value proposition, market segment, value chain, cost structure and profit potential, value network and competitive strategy. We apply Boolean method to support controlled comparison and eliminate unnecessary attributes. The Boolean analysis result shows that value proposition, cost structure and profit potential, value network and competitive strategy are the essential attributes. Furthermore, the result indicates that each attribute is a necessary condition, where all four conditions should be met simultaneously in order to be successful. With this result, we discuss essential consideration for those who are planning startup based on the sharing economy business model.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3472-3484
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• 2023

The objective of this research is to assess the seismic performance of different types of electrical cabinets in nuclear power plants. The cabinets under investigation are: (a) Case 1: a short single cabinet; (b) Case 2: a tall single cabinet; (c) Case 3: separated cabinets; and (d) Case 4: a combined cabinet with coupling effects. To accurately capture the real behavior of the cabinet, three-dimensional finite element models are developed using ANSYS with connection non-linearity. Frequency domain decomposition (FDD) is used to determine the dynamic properties of the cabinets from shaking table testing data, and these results are utilized to validate the numerical model. The close match between the experimental and numerical results obtained from the modal analysis demonstrates the accuracy of the numerical model. Subsequently, transient structural analysis is performed on the validated models to explore seismic performance. The results show that the acceleration response of the combined cabinet is lower than the single cabinet and the separated cabinet. This observation suggests that top anchors used to combine two different types of cabinets play a crucial role in assessing the efficiency and seismic resistance of electrical cabinets in a nuclear power plant.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1163-1169
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• 2023

In this study, the flow characteristics of the filter system were analyzed due to the effect of the density of the filter in the triple filter system. Flow analysis was performed as a flow passing through a porous medium. The flow characteristics of each filter system were analyzed by arranging filters with different densities in the forward flow flow and the reverse flow. The arrangement order of the triple filters was excellent in the case of forward fluid flow and in the case of higher density from the inside to the outside filter. In the reverse flow filter system, the performance of the system was the best in the case of reverse order filter arrangement. As a result of the analysis, Case II, which showed a pressure drop rate of 5.65% for forward flow, was the best in the reverse direction with a pressure drop rate of 14.25%. Considering reverse and forward flows, it was found that the optimal filter arrangement was most effective when the intermediate filter was the densest, and the inner or outer filter was less dense.

• 대한치과보철학회지
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• 제33권3호
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• pp.492-516
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• 1995

This study evaluated the responses of mandibular bones of mongrel dogs to loaded hydro xylapatite(HA) and titanium plasma spray(TPS) coated endosseous dental implants, using unloaded ones as the control group. after HA and TPS coated implants were implanted, their bone reactions with vital bones have been observed with light and scanning electron microscope(SEM) at the three periods of the 4th, 12th and 20th week. These reactions have been also compared in a histomorphometric method. The elemental distribution state of implants and the interface neighboring bone tissues have been measured with the energy dispersive analysis of X-rays(EDAX). The following results were obtained ; 1. The light microscopic analysis showed osseointegration in both the control group and the occlusal force loaded group ; Its degree was shown to be higher in the long-maintained and occlusal force groups. 2. The SEM analysis showed that both groups had osseointegration, In the case of TPS-coated implants, the coated layer was divided on the bone interface. In the case of HA-coated implants, there appeared a division between the metal and coated interface. 3. In the histomorphometric analysis, the measured ratio contaction bone of TPS-coated implants was $70{\pm}19$% in the case of no occlusal force ; it was $84{\pm}13$% in the case of occlusal force. The measured ratio contacting bone of HA-coated implants was $75{\pm}18$% in the case of no occlusal force ; it was $94{\pm}9$% in the case of occlusal force. However, there was no significant difference statistically(p>0.05). 4. Both groups showed that the ratio of calcium and phosphorous increased more in the bone tissues than on the bone to implant interface.

• 한국BIM학회 논문집
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• 제8권2호
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• pp.29-40
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• 2018

Recently, the free-form buildings are continuously increasing in the world. However, due to the shortage of experience and technology in the project of the free-form buildings, problems such as increase of construction cost, increase of air and deterioration of construction quality are occurring. In this study, data on the 27 free-form projects in Korea and abroad using digital fabrication were collected through the journals, reports, articles, and websites of the institutes and case studies were conducted based on the collected data. Based on the following case analysis, we conducted evaluation of case data analysis based on the knowledge domain specified in PMBOK. Evaluation of case data analysis shows that the application of digital fabrication is divided into positive and negative effects for each knowledge area in the free-form building project. Using the results of the analysis, we can confirm the knowledge field showing the positive effect on the free-form building project by using digital fabrication. However, the data scale of the project using the digital fabrication is not realized at present and research is insufficient. In Korea, a small number of specialists were interviewed and verified because experts do not exist much in korea. Therefore, this study is expected to suggest the necessity of applying digital fabrication in the free-form building projects in the construction industry.

• 한국태양에너지학회 논문집
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• 제40권2호
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• pp.1-10
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• 2020

Korea government published renewable energy obligation policy that public building must be supplied some part of total consumption energy (2019: 27%, 2020: 30%). RETScreen is freely available global energy tool that developed by Canadian National Energy Laboratory to quantify energy saving to compare conventional system. This program can be performed energy modeling, cost analysis, greenhouse gas emission analysis and financial analysis. In this study, GSHP (Ground source heat pump) heating and cooling system were studied for the energy deliverly and ROI (Return On Investment) in an office building. Three cases were studied according to the number of HP (Heat pump) units for the 1,000㎡ office building located in Daejeon. Results indicated that the energy delivery of the case 1 (1 HP unit) covered 57% of the office building heating and cooling energy consumption. The case 2 (2 HP units) covered 87.8% and the case 3 (3 HP units) covered 96.8% of the office building energy consumption. The ROI of the case 1 indicated 7.9 years. While 8.2 years for the case 2 and 9.7 years for the case 3.

• Journal of Computing Science and Engineering
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• 제5권2호
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• pp.131-140
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• 2011

Different cores typically share the last-level cache in a multi-core processor. Threads running on different cores may interfere with each other. Therefore, the multi-core worst-case execution time (WCET) analyzer must be able to safely and accurately estimate the worst-case inter-thread cache interference. This is not supported by current WCET analysis techniques that manly focus on single thread analysis. This paper presents a novel approach to analyze the worst-case cache interference and bounding the WCET for threads running on multi-core processors with shared L2 instruction caches. We propose to use an interference matrix to model inter-thread interference, on which basis we can calculate the worst-case inter-thread cache interference. Our experiments indicate that the proposed approach can give a worst-case bound less than 1%, as in benchmark fib-call, and an average 16.4% overestimate for threads running on a dual-core processor with shared-L2 cache. Our approach dramatically improves the accuracy of WCET overestimatation by on average 20.0% compared to work.

• 지역사회간호학회지
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• 제25권3호
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• pp.159-169
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• 2014

Purpose: The purpose of this study was to evaluate the effectiveness of case management for patients with hypertension on their health status and medical service utilization. Methods: This study was a secondary analysis of data collected for a larger study of chronic disease management in 2008 using the National Health Insurance Corporation database. A total of 12,944 patients who received case management for hypertension were included in this analysis. The subjects of case management were classified into subgroups, namely, over-use, under-use, and non-use groups according to the amount of medical service utilization. To compare the medical service utilization, a control group was selected randomly. The data were analyzed through descriptive statistics, McNemar test, and ANOVA. Results: All the subgroups displayed significant differences in blood pressure, self-management, social support, and their characteristics of medical service utilization. The total medical expense of the under-use and non-use groups increased after case management. However, there was no decrease in the medical expense of the over-use group. Conclusion: This finding suggests that there is a need to re-examine why patients overuse medical services and to supplement specific strategies for encouraging appropriate medical service utilization, and enhancing case management efforts for the over-use group.

• 대한두경부종양학회지
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• 제2권1호
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• pp.33-39
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• 1986

This is a clinical analysis of 24 cases of parotid gland tumor who were treated in the department of Surgery, Chonnam National University Medical School during the past 10years from January, 1976 to December, 1985. According to this analysis of total 24 cases, we concluded as follows; 1) 21 cases were benign tumors and 3 cases were malignant tumors. As the histopathological findings, benign tumor included 88%and malignant tumor 12%. Majority of benign tumor contained mixed tumor(86.7%), and the malignant tumor contained mucoepidermoid carcinoma (66.7%). 2) The peak age incidence was 40th in benign tumor and 50th in malignant tumor. 3) The chief complaints of patient was a painless mass and the duration of illness was average 5.2 years. 4) The mean size of mass was 4.5cm in diameter. 5) The surgical procedures were performed with excision 6 cases, superficial lobectomy 8 cases, wide excision with partial parotidectomy 4 cases, total parotidectomy 3 cases in benign tumors. In malignant tumors, total parotidectomy 2 cases and wide excision with partial parotidectomy 1 case were performed. 6) Major postoperative complications such as facial nerve palsy 7 cases (temporary ; 5 cases, permanent; 2 cases), Frey syndrome 1 case, seroma 1 case, hematoma 1 case, and wound infection 1 case were developed. The recurrence contained pleomorphic adenoma 1 case and mucoepidermoid carcinoma 1 case.