• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.712-715
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• 2006

This paper presents the nonlinear characteristics of the parametric resonance of a simply supported beam which is inextensible beam. For the beam model, the order-three expanded equation of motion has been determined in a form amenable to a perturbation treatment. The equation of motion is derived by a special Cosserat theory. The method of multiple scales is used to determine the equations that describe to the first-order modulation of the amplitude of simply supported beam. The stability and the bifurcation points of the system are investigated applying the frequency response function.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04a
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• pp.52-54
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• 2009

A plane wave expansion method(PWEM) was applied for photonic band structure calculation. We examined zero group velocity modes in photonic crystals. The zero group velocity was obtained in second band along G-K direction. We expanded Brillouin zone, and investigated on zero group velocity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.331-334
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• 2004

In clinical use, coronary stents keep coronary arteries open after expansion with a balloon catheter and prevent the expanded artery from collapsing. Coronary stents are positioned in artery by catheter with a balloon along a guide wire to the lesion site. Flexibility is one of important ability for delivery. In this paper, Palmaz-Schatz stent and Tenax complete stent were selected because these are the most representative of tubular stents. Finite element analyses for the stent system were performed using ABAQUS/Standard code. The present study estimated the flexibility of coronary stents due to loading directions. Moreover the present paper suggests a numerical method to test the flexibility of stents. In conclusion this paper shows how the finite element analysis can be effectively organized in the stent development.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.483-488
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• 2001

The RC beams subjected to bending and shear are an important substructure. After flexural cracking, the internal stress state in the beam could not be explained by the classical beam theory. In this study the internal force state factor is introduced to explain the stress state change in the RC beams. The internal force state factor of uniform load was expanded by superposition method using infernal force state factor of point load. As the load types change, the operator that would be calculated the internal force state factor was proposed.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.163-165
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• 2003

Over the past several years, the application extent of the real-time systems is being expanded with the progress of civilization. An effort to minimize power consumption at the system is being accomplished in several fields from the design of an analog/digital circuit up to the device level Things of this effort have included the power optimum-technique to minimize power consumption at the digital logic circuit and the dynamic managed skill by means o( the decision of the operating system. In this paper, we designed of low power system by using Power-optimized method. As an effective low-power design, we designed the low power system which it has a monitoring system within the main board and a personal computer.

• Journal of the Korean housing association
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• v.16 no.3
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• pp.69-77
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• 2005

The purpose of this study is to develop a automation for decision of the optimum stories in apartment buildings in order to assure the solar access right for neighboring areas. Compared to the results of the optimum stories by manual process through applying a legal case over solar access right, the proposed method provides more improved and expanded information by automating the computing process of decision of the optimum stories in apartment buildings. With the result of this research, it would be possible to furnish with advanced information for an amicable settlement against the civil petition and disputes, to reduce waste of the time and cost and to improve the efficiency of solar access right analysis works.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.4
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• pp.282-292
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• 2008

This study was conducted to evaluate work environment monitoring program(WMP) under Industrial Safety and Health Act in Korea. WMP was evaluated by focusing on five key elements, such as purpose, subject, scope, method and workers' participation. The operation status of WMP was evaluated by using questionnaire to workers and data published by Ministry of Labor(MOL). Compliance rate of WMP was less 13 % in manufacturing workplaces. Over-exposure rate was steady state by annual trend. The degree of workers' satisfaction to WMP was just 24 %. A critical problem with the current WMP is that the employer and workers are not acting as main players. For a fundamental improvement in working condition to take place, participation of workers should be expanded and be guaranteed by law.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.1
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• pp.65-77
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• 2017

The purpose of this paper is to develop a model of level evaluation for data governance that can diagnose and verify level of insufficient part of operating data governance. We expanded the previous study related on attribute indices of data governance and developed a level model of evaluation and items. The model of level evaluation for data governance is the level of evaluation and has items of 400 components. We used previous studies and expert opinion analysis such as the Delphi technique, KJ method in this paper. This study contributes to literature by developing a level evaluation model for data governance at the early phase. This paper will be used for the base line data in objective evidence of performance in the companies and agencies of operating data governance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.632-638
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• 2012

ZigBee network, based on PHY, MAC layer provides a specification for a suite of high level communication protocols using small, low-power digital radio based on an IEEE 802.15.4 standard. Meshing is a type of daisy chaining from one device to another. This technique allows the short range of an individual node to be expanded and multiplied, covering a much larger area. Each wireless technology that makes it to market serves a special purpose or function. Zigbee provides short-range connectivity in what is called a personal-area network (PAN). Within ZigBee PAN coordinator as manages an entire ZigBee network, the short range of frequency band was only selected because the technology allows typically less than 100 kbp or ZigBee troubles in retransmission processing and delaying data tranmission works to create unproductive condition of work. This research was proposed the method, based on short range frequency of zigBee nodes enable to long range of remote data transmission with specific algorithm tools.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.52-60
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• 2018

The winding of the motor stator coil is broken due to external stress and various factors. If the proper current is not injected when interturn fault(ITF) occurs, the fault can easily be expanded and the motor can be finally destroyed, resulting in many problems with time costs and safety. In this paper, the power loss limit concept, which is the inherent durability of each motor, is applied to secure safety by controlling the total power loss of the motor within the limits. So, we propose an algorithm that can control maximum torque per minimum power loss based on constant torque curve and power loss limit. To verify the proposed method, the simulation and experimental results with an Interior permanent magnet synchronous motor(IPMSM) having an ITF are shown.