• Journal of the Korean Society of Visualization
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• v.7 no.2
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• pp.56-63
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• 2010

In this work, a dielectrophoresis-based particle-separation device is developed which is to be used to continuously separate particles in microchannels. We fabricated the particle-separation device with combining the benefits of electrode-based DEP and insulator-based DEP. The DEP forces are generated by an array of electrodes located in both sidewalls of a main channel. According to the magnitude and frequency of electrical signals, particles with different dielectric properties experience different DEP forces, and therefore, continuously move along different streamlines in the main flow channel without need of pre-focusing process. Based on this mechanism, we examined the performance of the device by controlling the trajectory of polystyrene particles. This device is applicable to the investigation of dielectric properties of biological cells as well as the continuous separation of biological cells.

• Journal of Biosystems Engineering
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• v.18 no.4
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• pp.358-370
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• 1993

In Korea, fruit grading has been mainly done manually, and manual grading depends on human sense. Thus it is subjected to human error and is not always as consistent as would be desired. Therefore, a study on the development of fruit grader was initiated to improve the consistency of fruit grading. The sensitivity for fruit weight of the conventional spring type weight grader has a tendency to decrease by physical characteristics of spring which is used as a weight sensing unit. This study was carried out to develop weight measuring device for establishing the base of weight sensing unit of electronic weight grader. This device consists of a weight sensor using load cell, data acquisition system, and a microcomputer containing program to calculate fruit weight. The weight measuring device using load cell was developed to increase sensitivity of fruit weight. The result of this study showed that the weight sensing unit of electronic weight grader contributed to the improvement of performance of weight measuring device.

• Bulletin of the Korean Institute for Industrial Safety
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• v.2 no.1
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• pp.6-10
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• 2002

Requirements for Distributed Monitoring and Control Networks(DMCN) differ greatly from those of typical data networks. Specifically, my DMCN technology which employs a filedbus protocol is different from IP network protocol TCP/IP. In general, one needs to integrate fieldbus protocol and TCP/IP to realize DMCN over IP network or internet, which can be viewed as Virtual Device Network(VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance(PM). This paper suggests a basic framework for VDN using DMCN over IP network and a method to guarantee interoperability between devices and equipments.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.1
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• pp.41-46
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• 2008

With widespread use of the Internet and improvements in streaming media and compression technology, digital music, video, and image can be distributed instantaneously across the Internet to end-users. However, most conventional Digital Right Management are often not secure and fast enough to process the vast amount of data generated by the multimedia applications to meet the real-time constraints. In this paper, we propose the copyright protection using encryption of DCT coefficients and motion vector in MPEG-4 video codec of mobile device. This paper presents a new Digital Rights Management that modifies the Motion Vector of Macroblock for mobile device. Experimental results indicate that the proposed DRM can not only achieve very low cost of the encryption but also enable separable authentication to individual mobile devices such as Portable Multimedia Player and Personal Digital Assistants. The performance of the proposed methods have low complexity and low increase of bit rate in overhead.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.925-931
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• 2000

Refrigerating ability of vapor compression refrigerator is decided by the harmonic work of it's components such as compressor, condenser, evaporator, expansion device, and so on. In this study, choosing refrigerant injectors as a new one of expansion device, temperature change of the cold room, ice freezing ability, and power consumption on flowrate of injector and refrigerant charging condition are evaluated experimentally. As the results of this study, it is verified that the spray injection type refrigeration system has some merits according to the flowrate and spray pattern of injector and charging quantum of refrigerant. And there are some design factors such as spray pattern and shape of spray chamber to utilize and fabricate this refrigerant injection type refrigerator.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.213-217
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• 2001

Requirements for Device Networks differ greatly from those of typical data networks. Specifically, any device network technology which employs a fieldbus protocol is different from IP network protocol TCP/IP. In general, one needs to integrate fieldbus protocol and TCP/IP to realize device network over IP network or internet. Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance(PM). This paper suggests a basic framework for web-based predicted maintenance and a method to guarantee interoperability between devices and equipments.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.1-10
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• 2004

A haptic rendering system is proposed for a puncture task of a virtual vertebra model. To build a mesh model from medical images, Delaunay triangulation is applied and physical models are based on elasticity theory. Also, a redundant actuated 6 DOF parallel type haptic device is designed to display large force and to resolve the singularity problem of parallel type mechanisms. Haptic feeling of puncture task and the performance of the proposed haptic device are tested by two puncture task experiments.

• Journal of IKEEE
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• v.19 no.4
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• pp.514-519
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• 2015

We propose the multiple gate structure of double gate junctionless metal oxide silicon field oxide transistor (JL MOSFET) for device optimization. Since different workfunction within multiple metal gates, electric potential nearby source and drain region is modulated in accordance with metal gate length. On current, off current and threshold voltage are influenced with gate structure and make possible to meet some device specification. Through the device simulation work, performance optimization of double gate JL MOSFETs are introduced and investigated.

• Geomechanics and Engineering
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• v.5 no.1
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• pp.1-15
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• 2013

Pressure transducers are increasingly used within soil mass or at soil-structure interface for appraisal of stresses acting at point of installation. Calibration of pressure transducers provides a unique relationship between applied pressure and voltage or strain sensed by transducer during various loading conditions and is crucial for proper interpretation of results obtained from pressure transducers. In the present study an in-house calibration device is used to calibrate pressure transducers and the study is divided into two parts: 1) demonstration of developed calibration device for fluid and in-soil calibration of pressure transducers; 2) effect of soil layer thickness on the earth pressure cell (EPC) output. Results obtained from the present study revealed successful performance of the developed calibration device, and significant effect of sand layer thickness on the calibration results. The optimum sand layer thickness is obtained as 1.5 times the diameter of EPC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.312-315
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• 2001

Recently organic electroluminescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decrease rapidly as the luminance increase, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all organic thin film transistor(OTFT). The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(ppy)$_3$/BCP/Alq$_3$/Li:Al/Al. In OTFT, Polymer is used as an insulator and pentacene as an active layer. Detailed performance of the integrated device will be discussed.