• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.1-8
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• 2007

In this paper, we developed a file system architecture for portable multimedia devices. To enhance user convenience, the information about the stored files should be easily retrieved and organized. We defined NMD (Networked MetaData), which can organize the files in networked fashion by attaching user-defined attributes and relation between files. The NMD is stored in flash memory to utilize its nonvolatile property and low-power consumption, while multimedia files are stored in hard disk, an inexpensive mass storage. The experimental implementation showed that this architecture was able to save about 10% power compared to the hard disk NMD-store.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.119-124
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• 2001

Currently knowledge of strain in welds has mainly been obtained form strain gaging method:; that is directly attaching most of the material to the gate. The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics and the temperature changes of the TIG welded zone which is used with 3D ESPI system that is functionally modified through the laser ESPI system. This system employed the aluminum sheet-metal which are mainly used for the steel plate such as for the electronics, chemisry, food instrument and electronic appliances.

• International journal of advanced smart convergence
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• v.6 no.3
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• pp.38-44
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• 2017

Currently, wired gables have been installed or portable storage devices have been installed for data acquisition of flying drone. In this paper, we propose a technology to transmit data wirelessly by sensing information such as battery discharge value, acceleration, and temperature by attaching RF sensor to a drone. The purpose of this paper is to design and develop the monitoring technology of agriculture drone battery usage in real time using RF sensor. In this paper, we propose a monitoring system that can check real time data of battery changed value, temperature, and acceleration during pesticide control activity of agricultural drone.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.360-365
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• 2009

On this paper, piezoelectric generators using piezoelectric ceramics were designed and fabricated. Generators were made by attaching cymbal type metal plates on upper and bottom sides of a disc type piezoelectric ceramic. Generator converts wasting mechanical energy to electrical energy. Output voltage was increased when thickness of ceramic and displacement of vibration were increased. Temperature of the ceramic was increased when it generates, but the temperature rising was saturated at certain temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.169-170
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• 2008

On this paper, piezoelectric generators using piezoelectric ceramics were designed and fabricated. Generators were made by attaching cymbal type metal plates on upper and bottom sides of a disc type piezoelectric ceramic. Generator converts wasting mechanical energy to electrical energy. Output voltage was increased when thickness of ceramic and displacement of vibration were increased. Temperature of the ceramic was increased when it generates, but the temperature rising was saturated at certain temperature.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.109-120
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• 2008

An innovative method of changing a centrifugal low specific speed pump performance and pressure fluctuation by applying outlet flaps to impeller exit has been investigated. The outlet blade edge section corresponds to the trailing edge of wing on the circular-cascade, which dominates the pump performance and pressure fluctuation. Computational fluid dynamics (CFD) analysis of the entire impeller and volute casing and an experimental investigation are conducted. The pressure fluctuation and the vibration of the shaft are measured simultaneously. Kurtosis is applied as a dimensionless parameter with which the unevenness of velocity distribution at impeller outlet is indicated. The influence of the flaps on the pressure fluctuation is explained by the kurtosis. This paper presents a theoretical method of predicting the pump performance related to the attachment of a flap at impeller outlet.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.621-626
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• 2005

With precise GPS carrier positioning result, we can get attitude information if GPS antenna has adequate attaching position on the vehicle. In this case, baseline length information can be bandied as an additional measurement or constraint. In this paper, we have proposed a method to improve the attitude accuracy. To overcome nonlinearity of baseline observation model, we analyze attitude estimation result using existing estimation method like a least square method and Kalman filter, and apply a new nonlinear estimation method an unscented Kalman filter Finally we confirm the improvement of attitude estimation result in the case of appling the unscented Kalman filter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1288-1295
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• 2002

The column-type sensing element in building and mechanical construction parts was designed as three forces and three moments sensor by attaching strain gages approximately. Compared to conventional multi-component sensor, the designed sensor has high stiffness and low cost. The radius of the column was designed analytically and compared with finite element analysis. The interference errors between components were minimized by using addition and subtraction procedure of signals. The fabricated sensor was tested by using a deadweight force standard machine and a six-component force calibration machine. The calibration results showed that the 6-component forces and moments sensor had interference error less than 7.3 % between $F_x$ and $M_x$ components, and 5.0 % in case of other components.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.155-161
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• 2001

Currently knowledge of strain in welds has mainly been obtained from strain gaging method; that is directly attaching most of the material to the gage. The very few non-contact method are still in the early stage. One of the non-contact methods is by the use of the laser that has high-level of the accuracy for the measurement, and this laser also has excellent characteristics on which many studies for its applications are focused throughout the many fields. The dissertation is on the measurement of the strain caused by the characteristics and the temperature changes of the TIG welded zone which is used with 3D ESPI system that is functionally modified through the laser ESPI system. This system employed the aluminum sheet-metal which are mainly used for the steel plate such as for the electronics, chemistry, food instrument and electronic appliances.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1052-1055
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• 2001

In micro-drilling of brittle materials including glass, cracks occur at the exit surface. In drilling glass, the main type of crack is cone crack. Cone crack is generated by thrust force acting at the bottom surface of the workpiece. Cone crack size could be reduced by changing cutting conditions, but cone crack still existed. Two methods were proposed to prevent crack formation and perfect hole shapes were obtained. One method is attaching two glass plates with water and the other method is constraining two glass plates. The proposed methods eliminated tensile stress acting on the exit surface of glass and prevented crack propagation.