• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1790-1795
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• 2008

Energy scavenging is a technique that converts ambient energy, for example, vibration and light, to electrical energy in order to supply power to low power electronic devices such as ubiquitous sensors. In this paper, we propose an optimal operation condition of power delivery circuit and design strategy for energy scavenging system in which the generated power is order of microwatt and, consequently, efficient handling of power is critical. We also propose that high data transmission rate is more realistic optimal design objective rather than high energy efficiency. It is shown that disconnection of load from the storage capacitor right after data transmission reduces energy wasting and that optimal value of storage capacitor can be determined at this condition. The feasibility of our propose is proved by experiments and we believe that the proposed design strategy will promote the application of piezoelectric micropower generator to the ubiquitous sensor networks.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.2
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• pp.96-100
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• 2012

Existing, widely used industrial controller programmable logic controller (PLC) using the high cost and maintenance was a difficult problem. In addition, the network configuration was not easy. Thus, the filter press by remote control and management to improve productivity and shorten maintenance time. Variety of smart devices (smart phones, iPad, tablet PC, etc.) Remote control is possible by utilizing the existing controlled by the PLC addresses maintenance and improved performance compared to that of possible filter press control and management system was developed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.4
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• pp.272-277
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• 2013

In this paper the effect of instability and chaos in optical fiber networks based on the Internet is described. Nonlinear optical fiber effect especially Brillouin scattering in networks has emerged as the essential means for the construction of active optical devices used for all-optic in-line switching, channel selection, amplification, oscillation in optical communications and a host of other applications. The inherent optical feedback by the back-scattered Stokes wave in optical networks also leads to instabilities in the form of optical chaos. This paradigm of optical chaos in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical fiber communication. This paper attempts to present a survey and some of our research findings on the nature of Brillouin chaotic effect on Internet based optical communication.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.274-279
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• 2008

Roll to roll (R2R) manufacturing process, also known as 'web processing', has been tried for producing electronic devices on a flexible plastic or metal foil. To increase the performance and productivity the R2R process, effective control and on-line supervision for web quality becomes very important. Wrinkle is one of the defects, which is incurred due to compressive stresses. A system for on-line measurement of wrinkle is developed using area scan camera and machine vision laser. The 2D image, obtained by area scan camera, is produced by Gaussian regression method to characterize the wrinkle on a transparent web. The experiment proves that 0.3mm wrinkle height can be measured successfully with 74fps.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.311-314
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• 2009

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells, We evaluated hydrogen fed SOFC 50W system theoretically and got the results about the operating condition range from the comparison of the power efficiency, exhaust gas temperature, required heat for maintaining the operation temperature and operation time.

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.68-74
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• 2007

The fuel cells for portable application are attracted using a liquid fuel such as methanol and chemical hydride solutions. Recently, DBFC [Direct Borohydride Fuel Cell] is a candidate for power of portable electronic devices. In this work, the anion exchange membrane and non-precious catalyst for the DBFC were concerned. Anion-exchange membrane was fabricated by amination of polysulfone followed chloromethylation. Non-precious catalysts such as raney-Ni and Ag were used as an anode and cathode catalyst. The optimum conditions of catalyst slurry mixing and MEA fabrication were developed. The single cell performance using anion exchange membrane and non-precious catalyst was evaluated and the results were compared with cation exchange membrane [Nafion membrane] and precious catalysts.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.161-165
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• 2007

Recently by the development of the electronic engineering technology various mobile devices are developed. But their operation time need to be extended although capacity of the batteries are limited. We focused our attention to the portable SOFC system. Because SOFC has the high efficiency and a lot of strongness in comparison with other kinds of fuel cells. In addition they can be built as a self/non-reformable system and single/dual chamber system. So We evaluated some types of SOFC theoretically, and compared the results from the fuel and performance efficiency point of view.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1000-1007
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• 2007

In this study, structural vibration analyses of a smart unmanned aerial vehicle (UAV) have been conducted considering dynamic hub-loads of tilt rotor. Practical computational structural dynamics technique based on the finite element method is applied using MSC/NASTRAN. The present UAV(TR-S5-04) finite element model is constructed as a full three-dimensional configuration with different fuel conditions and tilting angles for helicopter, transient and airplane flight modes. In addition, the 3-dimensional supporting equipment structures of electronic devices are considered for vibration analysis. As the results of this study, transient structural displacements and accelerations are presented in detail. Moreover, vibration characteristics of structural parts and installed equipments are investigated for different fuel conditions and tilting angles.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.10a
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• pp.183-188
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• 1996

Films and coatings are used for an enormous and diverse set of applications including mechanical, electronic and optical devices, protection at high temperature, cutting tools enhancement and automotive use. Many of these applications require the various properties associated with inorganic and metallic / non-metallic materials; i.e., with ceramics. Therefore, a large number of coatings have been developed and used for a long time in the various fields, especially in mechanical one. As one of the mutual surface actions, the problems of contact stresses are complex. The relationship between load and stress are nonlinear. Besides, the material is often apt to deform plastically under low load. However, analytical solutions exist only for some simple problems. If a material has a complicated shape or inhomogeneous properties, numerical method must be used. In this paper, the analysis of the contact stress of the coating layer was solved, using the finite element method.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.3
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• pp.17-23
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• 2014

Recently, E-Commerce demands an integrated solution for online and off-line provided to customers on wired / wireless network and various mobile devices. Our E-commerce platform can use anytime, anywhere, for all consumers. And, it can take convenient and secure E-commerce service in mobile environment. So, we will implement a software platform base on the mobile environment that independent of the mobile OS. Particularly, our E-commerce platform is based on 3D GIS information for 3D electronic map. So, all users (customers) have got the more visible convenience. And, by using the e-catalog DB cloud server, off-line store operators can be built the online home-page easily. From now on our E-commerce platform based on 3D GIS can be usable at various E-commerce areas in the ubiquitous environment.