• Structural Engineering and Mechanics
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• v.34 no.2
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• pp.277-280
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• 2010

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.25-32
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• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.445-447
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• 2008

The CCTV systems is the most extensively used for a burglar proof, a crime prevention and a Prevention forest fires etc. The CCTV systems which is used in present is a PAN/TILT form. We want to control of CCTV systems motion by Up/Down, Left/Right, Zoom In/Out, Focus, TELE. We design a 8051 microcontroller board and a Key Controller and a Relay Controller. We conformed its feasibility through the simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.334-334
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• 2000

In this paper, sliding mode observer design principles based on the equivalent control approach are discussed for the systems which may not satisfy the matching conditions. We propose a new approach for designing a sliding observer and the proof of the stability of the state reconstruction error system for time-invariant systems using the Lyapunov method. The reaching time to the sliding surface, the sliding dynamics of the system, the stability of the reconstruction error system via Lyapunov method, sufficient conditions for the existence of the sliding mode are studied.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.31-36
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• 2022

Interval caching is one of the representative caching strategies used in multimedia streaming systems. However, there has been no theoretical analysis on interval caching. In this paper, we present an optimality proof of the interval caching policy. Specifically, we propose a caching performance model for multimedia streaming systems and show the optimality of the interval caching policy based on this model.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.64-71
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• 2012

An efficient cooling system is an essential part of the electronic packaging such as a high-luminance LED lighting. A special technology, Pulsating Heat Pipe (PHP), can be applied to improve cooling of a sealed, explosion-proof LED light fixture. In this paper, the characteristics of the pulsating heat pipes in the imposed thermal boundary conditions of LED lightings were experimentally investigated and a PHP device that works free of alignment angle was investigated for cooling of explosion-proof LED lights. Five working fluids of ethanol, FC-72, R-123, water, and acetone were chosen for comparison. The experimental pulsating heat pipe was made of copper tubes of internal diameter of 2.1 mm, 26 turns. A variable heat source of electric heater and an array of cooling fins were attached to the pulsating heat pipe. For the alignment of the heating part at bottom, an optimum charging ratio (liquid fluid volume to total volume) was about 50% for most of the fluids and water showed the highest heat transfer performance. For the alignment of the heating part on top, however, only R-123 worked in an un-looped construction. This unique advantage of R-123 is attributed to its high vapor pressure gradient. Applying these findings, a cooling device for an explosion-proof type of LED light rated 30 W was constructed and tested successfully.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.114-120
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• 2012

This paper describes the design, fabrication and testing of a micromachined resonant accelerometer consisting of a symmetrical pair of proof masses and double-ended tuning fork(DETF) oscillators. Under the external acceleration along the input axis, the proof mass applies forces to the oscillators, which causes a change in their resonant frequency. This frequency change is measured to indicate the applied acceleration. Pivot anchor and leverage mechanisms are adopted in the accelerometer to generate larger force from a proof mass under certain acceleration, which enables increasing its scale factor. Finite element method analyses have been conducted to design the accelerometer and a silicon on insulator(SOI) wafer with a substrate glass wafer was used for fabricating it. The fabricated accelerometer has a scale factor of 188 Hz/g, which is shown to be in agreement with analysis results.

• Journal of the Chungcheong Mathematical Society
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• v.10 no.1
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• pp.87-95
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• 1997

In general, the positive solution to biological reaction-diffusion equations is not unique. In this paper, we state the sufficient and necessary conditions of the existence of positive solutions, and give and the proof for the uniqueness of positive solutions for a certain elliptic interacting system.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.499-505
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• 2006

In this note, we give an elementary simple new proof of the main result of $Full{\acute{e}}r$ and Majlender [Fuzzy Sets and systems 136 (2003) 203-215] concerning obtaining minimal variability OWA operator weights.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.537-541
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• 2006

In this note, we give an elementary simple proof of the main result of $Full{\acute{e}}rand$ Majlender [Fuzzy Sets and systems 124(2001) 53-57] concerning obtaining maximal entropy OWA operator weights.