• Journal of KSNVE
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• v.8 no.4
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• pp.690-699
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• 1998

This paper discusses the techniques, procedures and the results of the ground vibration test(GVT) performed on the development aircraft and the simple procedure of FE model updating technique from the GVT results. The GVT was carried out using random excitation technique with MIMO(Multi-Input-Multi-Output) data acquistion method, and taking full advantage of poly-reference global parameter estimation technique to identify the vibration modes. In dynamic FE modeling, the aircraft was represented by beam elements and all dynamic analysis was performed using MSC/NASTRAN for this model. In updating procedure, the stiffness of the beam model was adjusted iteratively so as to get the natural frequencies and mode shapes close to the GVT results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.604-605
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• 2008

Modal participation factor (MPF) is a widely used in a mode-coupling squeal noise problem for finding the most sensitive component over a complex brake system in a vehicle using eigenvectors of sub-components. This methodology requires the problematic total response of system by the unstable squeal noise at a specific frequency as well as eigenvectors of each component belonging to brake system. In this paper, a unit-force response analysis is performed for intact total system to obtain eigenvectors of each component and then such data is directly used for the contribution analysis of a squeal noise problem. Since the eigenvectors of each component induced from virtual unit-excitation is most reliable owing to the intact boundary condition, it can be expected that the corresponding contribution analysis with MPF also provides a trustworthy result.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.341-348
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• 2001

In this study, a method is presented to find out a relationship between modes of a substructure and those of the system structure. Superelement analysis is performed for a full vehicle system, where the bus is partitioned by six parts. In this study, Modal Assurance Criteria(MAC) which is to represent the correlation between two mode shapes is used to investigate the contribution factor of each substructure for the full system. The proposed participation factor can be used for design of substructures to meet the design target of the total structural system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.72-77
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• 2011

In this study, the natural frequencies and mode shape of an external mounting pod were verified using the modal analysis and modal testing technique for a pod mounted on an aircraft. The procedure associated with the FEM building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FEM reflecting the results of the modal testing of a pod is built through the optimization, applied to the structural dynamic model of an Aircraft, used to verified the stability of vibration and flutter of an aircraft.

• Journal of Korean society of Dental Hygiene
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• v.15 no.5
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• pp.841-847
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• 2015

Objectives: The purpose of the study was to investigate the satisfaction with instruction medium according to learner attitude and lecture mode in the dental hygiene students. Methods: A web-based self-reported questionnaire was complected by 155 dental hygiene students in Cheonan from May 26 to June 5, 2015. The questionnaire consisted of general characteristics of the subjects, school adaptation, interest to learn, effort to learn, faculty centered lecture, learner centered lecture, self-directed learning, motivation to learn, characteristics of each subject, and satisfaction with lecture mode. The study was approved by institutional review board (IRB) by Baekseok University. Chi-square test and multivariate logistic regression were used to evaluate the satisfaction to medium of instruction according to explanation factors. Results: The lecture mode, opportunity and motivation to learn, interest to learn and effort to learn were the significant factors to satisfaction with instruction medium. In multivariate logistic regression model, the adjusted odds ratio was 6.28 for the opportunity to learn and 4.87 for the interesting to learn. Conclusions: The satisfaction with instruction medium is the most important factor that decides the lecture mode and learner attitude including opportunity to learn and concern to learn.

• Management & Information Systems Review
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• v.28 no.3
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• pp.99-115
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• 2009

This research analyzed determining factors of expenditure for processing fee by targeting trade show participants under a microeconomic approach in order to analyze determining factors of the participations of trade shows. As a result, with regard to the participation fees, income and the level of education seemed to be the socioeconomic factors that positively affected visitors in paying admission fees: and age and gender were negative elements. With regard to the participating businesses, the sales and the corporate history of the businesses were the positive elements to their willingness to pay the participation fees: however, the ratio of male and female personnel turned out to be a negative element in incurring the participation fees. The purchase of ticket was a positive mode-of participation factor to the visitors: however, distance tended to be a negative element for the visitors. For the participating businesses, the number of participation tended to be a positive element: however, distance was a negative one. The positive satisfaction factors that affected visitors' willingness to pay the participation fees included exhibited items, location, and schedules for events of the convention: for the participating businesses, the actual sales at the convention, the effects of advertisement and the level of satisfaction for location tended to play positive parts.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.4
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• pp.327-335
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• 2004

This study investigates the safety assessment of the potential for fretting-wear damages caused by foreign object in operating nuclear power plants. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for the helical type tubes with various conditions. The wear rate of helical type tube caused by foreign object is calculated using the Archard formula and the remaining life of the tube is predicted, and discussed in this study is the effect of the vibration of the tube on the remaining life of the tube. In addition, addressed is the effect of the external pressure on the vibration and fretting-wear characteristics of the tube.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.495-501
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• 2012

In this study, the natural frequencies and mode shape of an external mounting pod were verified using the modal analysis and modal testing technique for a pod mounted on an aircraft. The procedure associated with the FE model building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FE model reflecting the results of the modal testing of a pod is built through the optimization and will be applied to the structural dynamic model of an aircraft which is used to verified the stability of vibration and flutter of an aircraft.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.66-68
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• 2000

The Eigen analysis in large power system provides much useful information that is not got in nose curve. The branch participation factor is not quantitative information and is an indirect method calculating incremental change in branch reactive loss. But the Eigen sensitivity analysis to each mode is direct and provides of quantitative information but this method because of needing much time is used in large power system. In this paper the Hessenberg method is used to obtaining dominant eignvalues and corresponding eigenvectors of Jacobian matrix. Ranking the critical contingencies is done by computing the Eigen sensitivity of each dominant eignvalues for changes of each line. The proposed algorithm is tested on the New England 30-bus system and KEPCO system in the year of 2000, which comprises of 791-bus and 2500-branches.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.36-49
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• 2018

This study analyzed the public preference and acceptance regarding renewable energy projects through Choice Based Conjoint Analysis. The results show that the surveyed respondents consider the leading authority of the projects, as the most important factor when considering participating in renewable energy initiatives. Following this, the mode of participation and profit distribution and the power plant location are also viewed as important, whereas participation through decision making regarding the projects was less important. Also when participating in renewable energy projects, respondents tend to prefer to financially participating through loans or owning shares rather than volunteering support for the business such as sharing information, stating one's views, or providing cooperation and coordination. Therefore, the focus is on distributional justice, such as financial investment and profit distribution, rather than procedural justice, for instance decision making. When analyzing the part-worths utilities for the participation attribute, the respondents most preferred to receiving dividends based on earnings by owning shares with the local government in charge of the entire projects. As a consequence, the results suggest that it is important to have local government get involved and have trust-worthy governing systems in place for the initiation of the public participating-renewable energy projects.