• International Journal of Aeronautical and Space Sciences
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• v.17 no.2
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• pp.195-203
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• 2016

In order to overcome the influence of system stability and accuracy caused by uncertainty, estimation errors and external disturbances in Eight-Rotor MAV, L2 gain control method was proposed based on interval type II fuzzy neural network identification here. In this control strategy, interval type II fuzzy neural network is used to estimate the uncertainty and non-linearity factor of the dynamic system, the adaptive variable structure controller is applied to compensate the estimation errors of interval type II fuzzy neural network, and at last, L2 gain control method is employed to suppress the effect produced by external disturbance on system, which is expected to possess robustness for the uncertainty and non-linearity. Finally, the validity of the L2 gain control method based on interval type II fuzzy neural network identifier applied to the Eight-Rotor MAV attitude system has been verified by three prototy experiments.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.169-178
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• 2010

In this study, the optimal strengthening by micro genetic algorithm(${\mu}$-GA) method is proposed for improvement of load-carrying capacity of RC hollow slab bridges using external prestressing. The Qeen-post type and King-post type are considered for the optimal strengthening. The type for optimal strengthening, deviator, areas of tendons and the number of anchor are calculated by ${\mu}$-GA. The objective function is constituted with dimensionless cost of tendon and steel for optimal strengthening. The constraints are formulated by design specification for bridges and anchors. The validity of this study is presented by analysis of the results after the optimal strengthening of the RC hollow slab bridge.

• Asia pacific journal of information systems
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• v.10 no.2
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• pp.1-22
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• 2000

This paper presents an exploratory research on the application of the Technology Acceptance Model(TAM) to the domain of object orientation to investigate the validity of TAM in the perspective of its causal relationships. In the Management Information Systems(MIS) area, TAM has been applied to computer usage behavior as a specific technology adoption model. This paper also suggests the factors that affect the technology acceptance of object orientation in U.S. organizations through a modified TAM. Two major research questions are addressed. First, this research investigates the effect of these external variables on the dependent variable, the actual usage of object orientation in the viewpoint of knowledge interaction between structured methods and object orientation. Second, is TAM valid for the technology acceptance of object orientation in terms of its causal relationships? This study empirically explores the impact of the external variables on the level of actual usage of object orientation via the mediating variables in TAM. A structured questionnaire is administered to Data Processing Management Association(DPMA) professionals in US. The result of this study reveals one important contradictory finding that is not consistent with expectations based on related theory. TAM does not accommodate the technology acceptance of object orientation perhaps because object orientation is a complex and organization-level adoptive technology or the measures for the mediating constructs in TAM may not be appropriate in industry settings.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.565-565
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• 2004

Due to limitation of resources and increasing concerns about environment, reverse logistics has received growing attention in recent years. In this paper, we propose three types of reverse logistics networks based on reuse of returnable containers, materials recycling process and remanufacturing for parts reuse. First, the sender in the re-usable item network supplies containers for the recipient and orders either new containers from external supplier or returnable containers cleaned from the container depot. Second, the recycling center in the proposed recycling network collects either end of life products from customer or faulty goods from manufacturer, collected products are dismantled into materials and materials go into recycling process. Finally, the manufacturer in the proposed remanufacturing network has two alternatives for supplying parts: either ordering the required parts to external supplier or overhauling disassembled parts and bringing them back 'as new' conditions. In this product recovery environment, we build optimal order quantity models to minimize the total logistics costs related to reverse logistics network. The validity of the proposed model is investigated through comprehensive computational experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.639-647
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• 2007

This paper proposed the novel method that can realize the parallel coupled line(PCL) band-pass filter with directly coupled feeding structure by means of transforming the first and last PCL sections of the conventional PCL band-pass filter into K-inverters, then substituting T-type equivalence for K-inverter. The proposed method supplies simple design formulae and can considerably reduce time and efforts needed to optimize filter performance when compared to reported methods using external Q or equivalent parameters. On the basis of the proposed method, the band-pass filter using directly coupled feeding structure and having 18% fractional bandwidth was designed and fabricated. The validity of proposed method was proven by the measured result.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.170-179
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• 1997

This paper presents a hybrid navigation system for AUV to locate its position precisely in rough sea. The tracking system is composed of various sensors such as an inclinometer, a tri-axis magnetometer, a flow meter, and a super short baseline(SSBL) acoustic position tracking system. Due to the inaccuracy of the attitude sensors, the heading sensor and the flowmeter, the predicted position slowly drifts and the estimation error of position becomes larger. On the other hand, the measured position is liable to change abruptly due to the corrupted data of the SSBL system in the case of low signal to noise ratio or large ship motions. By introducing a sensor fusion technique with the position data of the SSBL system and those of the attitude heading flowmeter reference system (AHFRS), the hybrid navigation system updates the three-dimensional position robustly. A Kalman filter algorithm is derived on the basis of the error models for the flowmeter dynamics with the use of the external measurement from the SSBL. A failure detection algorithm decides the confidence degree of external measurement signals by using a fuzzy inference. Simulation is included to demonstrate the validity of the hybrid navigation system.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.79-84
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• 2012

This study aimed to analyze the nonlinear buckling of ring-stiffened circular cylinders under uniform external pressure, e.g. hydrostatic pressure, considering material nonlinearity and initial imperfection. In the present study, we analyzed the collapse pressure of pressure vessels using ANSYS Workbench, which is a framework of finite element methods. First, linear buckling analysis is performed to find collapse modes of the model. Second, scaling the first mode shape with small factor, geometric model is pre-deformed. And then, by analyzing the nonlinear buckling of the pre-deformed shape, the collapse pressure is estimated. To verify the validity of the analyses, we compared the results with Ross' experimental results. Finally, we applied it to ring-stiffened circular cylindrical shell of the pressure hull of a small submarine.

• Animal cells and systems
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• v.14 no.3
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• pp.213-219
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• 2010

Bottlenose dolphins (Tursiops sp.) commonly inhabit Korean waters, including the coastal waters of Jeju Island. However, their taxonomic position was unclear because of the validity of this genus. The genus Tursiops has recently been determined to comprise two species: the common bottlenose dolphin (Tursiops truncatus) and the Indo-Pacific bottlenose dolphin (Tursiops aduncus). To confirm the taxonomic position of bottlenose dolphins frequenting the coastal waters of Jeju Island, the external morphology and osteology of specimens from Jeju Island were examined. Photographs of free-swimming individuals were also used for determining external morphological characters. The cranial and meristic measurements fell within the ranges of T. aduncus. Osteological ratios were also consistent with those of T. aduncus. The presence of a prominent ventral spot was observed among some individuals. As a result, the dolphins mainly distributed in the coastal waters of Jeju Island were identified as Indo-Pacific bottlenose dolphins (T. aduncus) in terms of their cranial characters and ventral spotting. We propose a new Korean name, 'Nambang-keun-dol-go-rae'.

• Journal of Korean Society for Quality Management
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• v.46 no.4
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• pp.911-922
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• 2018

Purpose: This study provides an overview of the Product Liability Act which was revised in 2017 and took effect in 2018. It analyzes the effects of the revised Act on corporate management from internal and external perspectives to present coping strategies so that companies can synthetically respond to such effects. Methods: In order to achieve the purpose of this study, experts like companies, academia, governmental institutions, and consultants were invited, and Delphi techniques were applied to derive means, standard deviations, and Content Validity Ratio. Results: In this study, based on two expert questionnaire surveys, strengths and weaknesses of the internal environment of companies and opportunities and threats of the external environment were derived, followed by provision of S/O, W/O, S/T, and W/T strategies. Conclusion: To fundamentally remove the causes of accidents on their products, the relevant companies should strengthen the activities to increase product safety. They shall cooperate with suppliers to arrange the measures to speedily secure safety of consumers.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.381-391
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• 2018

The purpose of this study was to develop a measurement tool for education satisfaction of sport ethics program and to verify its validity. To achieve this goal, 3 steps of experimental processes were carried out. In the first step, the pilot questionnaires was created on the basis of previous researches regarding sport ethics education, education satisfaction, and response assessment. In the second process, as a pilot survey step, construct validity was obtained through exploratory factor analysis and confirmatory factor analysis of the measure constructed by the first process. In the third process, as a main survey step, external validity was obtained through difference verification, then questionnaires were constructed based on the analyzed contents. As a result of these steps, a measurement tool for educational satisfaction of sport ethics program composed of 17 questionnaires was developed. It consists of education contents (6), instructor competency (5), and education effect (6).