• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.442-450
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• 2006

This paper describes the new modal analysis method to detect the presence of the breathing crack in a general rotor system with disk asymmetry and stator anisotropy. It is proposed that the modal analysis using directional frequency response functions (dFRFs), which, accounting for the directivity in modes, clears the heavily over-lapping of other harmonics occurring from non-isotropic properties in addition to those due to crack, can provide an effective method to detect the modes by a crack. The simulations from the simple general rotor model show that the r-dFRFs (reverse dFRFs) for asymmetry confirms a good indicator of the presence of the breathing crack and the instability is primarily influenced by the shaft asymmetry than the breathing crack.

• Journal of Korean Institute of Industrial Engineers
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• v.12 no.2
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• pp.1-11
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• 1986

This study is concerned on computerized analysis of COG, torques and EMG amplitudes in weight-lifting motion. The results show that; (1) torques on major joints show a rather consistent relationship with respect to the sequence of four distinct motions in weight-lifting, (2) analysis of EMG amplitudes is a sensitive measure of both athlete's skill and his potential capability, and (3) range of COG variations can be used as indicator of motion stability, existence of undesirable posture, and target muscle for intensive training. A computerized routine, which includes analyses on COG, EMG and torque, is a scientific tool for coaching athletes. In addition, an Expert System which includes CAD routine was developed in order to promote better understanding for athletes and coaches.

• Earthquakes and Structures
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• v.12 no.2
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• pp.177-189
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• 2017

For energy-based seismic design, a simplified normalized cumulative hysteretic energy spectrum proposed for obtaining hysteretic energy as energy demand is the main objective in this paper. The dimensionless parameter, ${\beta}_{Eh}$, is presented to express hysteretic energy indirectly. The ${\beta}_{Eh}$ spectrum is constructed directly through subtracting the hysteretic energy of single degree-of-freedom (SDOF) system energy equation. The simplified ${\beta}_{Eh}$ spectral formulation as well as pseudo-acceleration spectrum of modern seismic provisions is developed based on the regression analysis of the large number of seismic responses of SDOF system subjected to earthquake excitations, which considers the influence of earthquake event, soil type, damping ratio, and ductility factor. The relationship between PGV and PGA is established according to the statistical analysis relied on a total of 422 ground motion records. The combination of ${\beta}_{Eh}$ spectrum and PGV/PGA equation allows determining the cumulative hysteretic energy as a main aseismic design indicator.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.2
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• pp.51-59
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• 2015

It is generally recommended to use EVM as an efficient means for measuring project performance and progress so that the EVMS user could manage his project successfully. In spite of it's favorable intention, most project participants think it as a heavy load or a sub practiced job with low responsibility. Even though there are lots of variables triggering unpredictable troubles in EVM application, EVM still could be a valuable project health indicator. In this paper we introduce a performing method for EVM based on system engineering process.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.282-291
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• 2006

This study investigated the inactivation of the total coliform, an indicator organism in chlorine and chlorine in order to control microbial regrowth for water distribution systems and select an appropriate disinfection strategy for drinking water systems. The disinfection effects of chlorine and chlorine dioxide with regard to the dosage of disinfectant, contact time and DOC was investigated experimentally. In spite of the consistency of chlorine residuals at approximately 0.2 mg/l, bacteria regrowth was detected in the distribution system and it was confirmed by the scanning electron microscope results. The influence of organic carbon change on the killing effect of chlorine dioxide was strong.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.999-1006
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• 2003

This research presents efficient operation schemes that is emphasized on mailing center's automation parts. We utilized the automation indicator to analyzed the mailing center system. For automation of the mailing center, we proposed the sorting automation alternative of registered mail, automation of conveyance system between workshops and the Up-Grade scheme for process improvement in mailing center. The selection of the registered mailing f s automation alternatives is composed of the AHP(Analytic Hierarchy Process) method. Through the analysis of the space and the quantity of materials, the simulation experiments are conducted to examine conveyance equipment possibility of the mailing center. By simplifying the mailing center conceptually, we proposed the upgrade of process for the mailing center system. The result of this research can give some ideas to people who are formulating a policy for the mailing center operation.

• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.9-14
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• 2017

In this paper, we propose the smart belt system for preventing loss of items using Beacon. The proposed system monitors the distances of the registered items via the belt that is always worn. The belt determines the loss of the items by measuring the relative distance via RSSI (Received Signal Strength Indicator) value of the signals received from the BLE (Bluetoothl Low Energy) sensor, which is attached on the items such as bags and wallets. If the registered item is determined to be lost, the belt rings to remind the user of the loss. The missing status could be known to users through the smartphone application connected to the belt. The smartphone application communicates with the belt using Beacon, and provides users with a quick and easy way to check the status of their items.

• Journal of Engineering Education Research
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• v.13 no.2
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• pp.7-11
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• 2010

As the development of the computer and communication technologies, the ubiquitous society can be realized to the world early in the future. Thus, the localization system in Wireless Personal Area Network (WPAN) is required for many users of ubiquitous society to provide the ubiquitous computing based applications in respective of anytime and anywhere. In this paper, we propose the distance measurement scheme that is based on the distance measurement using RSSI (Received Signal Strength Indicator) of sensor module considering of two distance conditions for the localization system using Zigbee in WPAN. Also, the localization errors of the proposed scheme are analyzed in the three scenarios that the mobile module tracks in the in $6m{\times}6m$ scaled experimentation area. In addition to this, the monitoring subsystem is developed using GUI (Graphical User Interface) in order to monitor the location of the moving objects accurately and user-friendly.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.111-117
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• 2013

The autonomous driving method using magnetic sensors recognizes the position by measuring magnetic fields in autonomous robots or vehicles after installing magnetic markers in a moving path. The Position estimate method using magnetic sensors has an advantage of being affected less by variation of driving environment such as oil, water and dust due to the use of magnetic field. It also has the advantages that we can use the magnet as an indicator and there is no consideration for power and communication environment. In this paper, we propose an efficient sensor system for an autonomous driving vehicle supplemented for existing disadvantage. In order to efficiently eliminate geomagnetism, we analyze the components of the horizontal and vertical magnetic field. We propose an algorithm for position estimation and geomagnetic elimination to ease analysis, and also propose an initialization method for sensor applied in the vehicle. We measured and analyzed the developed system in various environments, and we verify the advantages of proposed methods.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.139-155
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• 2012

A fundamental concepts of business environment changes and the importance of stakeholder's value creation is changing in the business. This study ISO9004: 2009 quality management system of Category 5: Strategy and Policy, Category 10: improvement, innovation and learning (Note) SBK target was to develop a model that is the company's sustained success. Three concepts of the new revision of ISO9004" in response to environmental changes," "learning", "innovation" (Note) SBK applied to the project settings and talent establish long-term vision was to establish the process as the organization's learning content was TDR for the creation of exceptional and innovative programs were introduced. As a result, (Note) SBK three years of continuous business performance indicator has grown dramatically to more than 50% continued success is going to create business models. But 100 years to accomplish the vision, ISO9004 model needs to extends the entire category as a management system to achieve the optimization needed.