• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.413-417
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• 1997

Distributed piezoelectric sensor and actuator have been designed for efficient vibration control of a cantilevered beam. Both PZT and PVDF are used in this study, the former as an actuator and the latter as a sensor for our integrated structure. For the PZT actuator, the position and size have been optimized. Optimal electrode shape of the PVDF sensor has been determined. For multi-mode vibration control, we have used two PZT actuators and a PVDF sensor. Electrode shading of PVDF is more powerful for modal force adjustment than the sizing and positioning of PZT. Finite element method is used to model the structure that includes the PZT actuator and the PVDF sensor. By deciding on or off of each PZT segment, the length and the location of the PZT actuator are optimize. Considering both of the host structure and the optimized actuators, it is designed that the active electrode width of PVDF sensor along the span of the beam. Actuator design is based on the criterion of minimizing the system energy in the control modes under a given initial condition. Sensor is designed to minimize the observation spill-over. Modal control forces for the residual(uncontrolled) modes have been minimized during the sensor design. Genetic algorithm, which is suitable for this kind of discrete problems, has been utilized for optimization. Discrete LQG control law has been applied to the integrated structure for real time vibration control. Performance of the sensor, the actuator, and the integrated smart structure has been demonstrated by experiments.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.3
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• pp.151-169
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• 2014

We propose a new technique for autonomous navigation and travelling of mobile robot based on ultrasonic sensors through the narrow labyrinth that leave only distance of a few centimeters on each side between the guides and the robot. In our current implementation the ultrasonic sensor system fires at a rate of 100 ms, that is, each of the 8 sensors fires once during each 100 ms interval. This is a very good firing rate, implemented here for optimal performance. This paper presents an extensively tested and verified solution to the problem of obstacle avoidance. Our solution is based on the optimal placement of ultrasonic sensors at strategic locations around the robot. Both the sensor location and the associated navigation algorithm are defined in such a way that only the accurate radial sonar data is used for accurate travelling.

• Design & Manufacturing
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• v.2 no.4
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• pp.48-53
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• 2008

We injection molded a thin type of plate and wedge type of plate with micro prizm patterns on its surface and investigated the fidelity of replication of the micro pattern depending on the process parameter such as mold temperature, melt temperature, injection rate or packing pressure. The size of the $90^{\circ}$ prizm pattern is $50{\mu}m$ and the size of the plate is about $335mm{\times}213mm$ and $400mm{\times}400mm$. The thicknesses are 2.6mm and 0.7mm at each edge of the wedge type of plate and 1mm at each edge of the thin type of plate. The fidelity of the replication turned out quite different according to the process parameters and location of the patterns on the plate. We measured the cavity pressure and temperature in real-time during the molding to analyze the effect of the local melt pressure and temperature on the micro pattern replication.

• Journal of Animal Environmental Science
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• v.20 no.2
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• pp.63-68
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• 2014

Environmental heat stress by global warming has a severe effect on the productivity of livestock and, in particular, on that of dairy cattle. Heat stress during high temperature environment directly and indirectly affects milk yield, milk quality and physiological response. This study was conducted to investigate the effects of heat stress on productivity and physiological responses of livestock. Temperature-humidity data logger were established inside the feedlot for measuring real time changes in the feedlot environment. Milk was collected every day for analysing the productivity of dairy cattle. Blood sample and respiration of dairy cattle were collected once in a week for investigating the physiological response factors. Blood component concentration associated with lipolysis metabolism and milk production showed change during tropical night period. Temperature humidity index (THI) of a specific location inside the feedlot showed continuously high levels.

• Journal of Digital Contents Society
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• v.6 no.3
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• pp.175-178
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• 2005

Wirtual reality(VR) is both one of the high-technology and main paradime in leading next genaration of 21th century. It`s application spectrum is various and lead to numorous revolotion as well as transtion in technical aspect. These change is a good procept of it`s comes to receive at real-time tracking using Web-Cam. The method research which is the possibility of doing location tracking which is accurate.

• Proceedings of the Korean Magnestics Society Conference
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• 2013.05a
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• pp.19-20
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• 2013

Thermoelectic properties of the typical thermoelectric host materials, the tellurides and selenides, are known to be noticeably changed by their volume change due to the strain [1]. In the bismuth telluride ($Bi_2Te_3$) crystal, a substitution of rare-earth element by replacing one of the Bi atoms may cause the change of the lattice parameters while remaining the rhombohedral structure of the host material. Using the first-principles approach by the precise full potential linearized augmented plane wave (FLAPW) method [2], we investigated the Ce substitution effect on the thermoelectric transport coefficients for the bismuth telluride, employing Boltzmann's equation in a constant relaxation-time approach fed with the FLAPW wave-functions within the rigid band approximation. Depending on the real process of re-arrangement of atoms in the cell to reach the equilibrium state, $CeBiTe_3$ was found to manifest a metal or a narrow bandgap semiconductor. This feature along with the strong correlation effect originated by the 4f states of Ce affect significantly on the thermoelectric properties. We showed that the position of the strongly localized f-states in energy scale (Fig. 1, f-states are shaded) was found to alter critically the transport properties in this material suggesting an opportunity to improve the thermoelectric efficiency by tuning the external strain which may changing the location of the f-sates.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.3 s.37
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• pp.23-30
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• 2006

The case of a forest area has tome limitations of adopting a ground surveying like as TS (Total Station) and RTK-GPS (Real Time Kinematic-GPS) due to the specificity of the forest area. Therefore, the new method, is different from exist the cadastral re-surveying method in a metro area and a cropland, is applicably considered in the forest area. In this paper, we suggest the applicability of the digital cadastral map of forest which is used at KLIS. According to the result of study, the most important area error value for adopted in the cadastral re-surveying is almost contained the error tolerance. Therefore, KLIS data, if it is related with the actual reference data for adjusting the location boundary, is suitable to be adopted in the cadastral re-surveying.

• Journal of National Security and Military Science
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• s.2
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• pp.261-283
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• 2004

To build up the military strength based on information oriented armed forces, the Korean ministry of national defense (MND) promotes the defense CALS (Continuous Acquisition and Life cycle Support) initiative for the reductions of acquisition times, improvements of system qualities, and reductions of costs. These defense CALS activities are the major component of the underlying mid and long term defense digitization program and the ultimate goal of program is to bring a quick victory by providing real-time battlefield intelligence and the economical operations of the military. The concept of defense CALS is to automate the acquisition and disposition of defense systems throughout their life cycle. For implementing defense CALS, the technology for exchange and sharing CALS standard data that is created once and used many times should be considered. In order to develop an efficient CALS information exchange and sharing system, it is required to integrate distributed and heterogeneous data sources and provide systematic search tools for those data. In this study, we developed a content based search engine technology which is essential for the construction of integrated data environments. The developed technology provides the environment of sharing the CALS standard data such as SGML(Standard Generalized Markup Language) and STEP(Standard for The Exchange of Product model data). Utilizing this technology, users can find and access distributed and heterogeneous data sources without knowing its actual location.

• Journal of Convergence Society for SMB
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• v.6 no.3
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• pp.37-41
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• 2016

In this paper, we propose a fire alarm system that utilizes Wi-Fi to alarm multiple people at once. This system, based on Arduino, uses smoke, flame and temperature sensor units to sense fire and send detection data to a server via wireless communication system. The server uses stored data to relay current fire situations gathered from nearby sensors to smartphones. It also automatically reports the fire using location data from sensors. Using this system, we were able to retrieve fire alarm from sensors via push notification of our smartphone. We also confirmed the establishment of linkage with sensors and automatic report of fire via SMS. From this result, the possibility of sending real-time notifications via the Internet toward nearby smartphones about disasters such as conflagration has been proven to be feasible.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.698-704
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• 2011

This study aims to facilitate and increase the performance of the Traffic Analysis System which receives the location information of vessels sailing along the coast all over the country in real time and analyzes the vessels' sailing situation. Especially, the research has a signification that the system is designed with the application of Quad-Tree and R-Tree data structure in order for system users to search necessary information quickly and effectively, and it verifies the improvement of the performance by showing experiment results comparing the existing Traffic Analysis System to newly upgraded Traffic Analysis System.