• Convergence Security Journal
• /
• v.11 no.1
• /
• pp.3-10
• /
• 2011

This paper proposes DPA(Dynamic Priority Assignment) MAC protocol to improve the traffic QoS on the HFC-CATV(Hybrid Fiber Coax CAble TeleVision) network. In results, DPA MAC protocol is the best performance compare with to IEEE 802.14a MAC in mean request delay, mean access delay. Also, the paper prove a reliability of proposed protocol through comparison between performance analysis and simulation result of DAP MAC protocol.

• KIEAE Journal
• /
• v.2 no.1
• /
• pp.63-68
• /
• 2002

Solar sunlighting systems are useful to apply for most buildings. This study aims to analysis the development and architectural application of solar sunlighting systems. For the purpose, abroad developing situation of solar sunlighting systems were investigated and analyzed literally. And, by case studies, architectural application methods are analyzed. As results, light pipe systems are mainly used for small building and houses. Also solar mirror systems are used for atrium and underground spaces. Lens-fiber systems are applied for high rise buildings and office buildings which internally have no influx of sunlighting. Some application suggestion in our country are discussed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.298-303
• /
• 2004

It is well known that a discharge in oil is the source of various physical phenomena. Ultrasonic-wave detection is a useful method to the diagnosis of the transformer-insulation condition. Conventionally, ultrasonic waves are detected by Piezo-electric transducer, and we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based rut the needle-plane electrode system in oil and applied AC high voltage Ultrasonic waves were detected and showed signal- analysis results with wavelet transform.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2001.11a
• /
• pp.118-123
• /
• 2001

The objectives of this research are to verify the structural stability and estimate the resisting performance of Stressed-Arch system during the construction process. Full scale models are taken to obtain the objective shape by the Dynamic Relaxation Method. As a result, it measured more strain than yielding strain at the extreme fiber of top chord member on the crown, but it is shown that members have the sufficiently compressive resisting performance as well as a considerable strain recovery capacity under unloading. Therefore, it is confirmed that Stressed-Arch system apparently have sufficient range of the structural capacity, but it is required that the elasto-plastic behavior of this system must be verified more detailed by numerical analysis and experiments.

• Proceedings of the KIEE Conference
• /
• 2000.11b
• /
• pp.287-289
• /
• 2000

Induction heating is utilized in a large and ever-increasing number of application. The most prominent of these are billet heating heat treating, metals joining, and metal melting. In these day, heating roll, a kind of induction heating, is widely used in curing of coatings and fiber industry. In this paper, at first, treated that heating roll's characteristics equation. The second, analysis of magnetic flux and eddy currents distribution using FEM.

• Analytical Science and Technology
• /
• v.17 no.6
• /
• pp.527-531
• /
• 2004

Treatment with aqueous sodium hydroxide solution plays an important role to impart certain desirable properties - feel and luster on the surface of polyester fiber. In this process alkali wastewater contains disodium terephthalate, ethylene glycol (EG) and residual sodium hydroxide. In this paper we report a new method containing the pretreatments of derivatization with benzoyl chloride and solvent extraction using pentane. The calibration curve of EG determined by GC/MS-SIM shows a good linearity in the range of 0.1 to $25{\mu}g/mL$ having the standard deviation of ${\leq}8.7%$. The recovery and the detection limit of this method are 91.9-93.7% and $0.05{\mu}g/mL$ respectively.

• 연구논문집
• /
• s.24
• /
• pp.81-96
• /
• 1994

To investigate failure mechanisms observed in carbon-phenolic thermal insulators, differential equations which govern the decomposition process in a deformable anisotropic porous solid are derived for three-dimensional axisymmetric constructions. The governing equations not only couple the material deformation with pore pressure, but also couple pressure and temperature, which means that heat convected by the pyrolysis gases is properly accounted for. Then the Bubnov-Galerkin finite element method is applied to these equations to transform them into a semidescrete finite element system. A thermal insulation liner in the cowl region under typical operating conditions is analyzed to find a mechanism for plylift. The results from the structural analysis show across-ply failure in the cowl zone. The mechanism for plylift is hypothesized as a sequential procedure : 1) the across-ply failure which is the precursor to plylift and 2) the local fiber buckling caused by generation of excessive in-plane compressive stress. To prevent plylift, the across-ply stress can be reduced by using appropriate material ply angles in cowl zone design.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1496-1499
• /
• 2005

This paper was represented an electrostatics distribution analysis using FEM(finite element method) with industrial type Inkjet plotter. Here, we know electronic value with each system position by experiment. these were decreased by discharge through earth and electricity shielding. According to industrial development, all fields using chemical instrument and material are generated an electrostatics. Based on these, the big large position of electrostatics was obtained metal base of controller, nonconductor fiber between two rubber roller, head controller by moving roller etc., Therefore these were showed an electrostatics generation source and by rubbing and meager profits electric charge.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.34-36
• /
• 1998

Induction heating is utilized in a large and ever-increasing number of application. The most prominent of these are billet heating, heat treating, metals joining, and metal melting. In these day, heating roll, a kind of induction heating, is widely used in curing of coatings and fiber industry. We designed and manufactured heating roll that in order to distribute uniform temperature on the roll's surface. Then Heating roll's characteristic analysis was studied and performed the test of temperature distribution.

• Journal of the Optical Society of Korea
• /
• v.8 no.4
• /
• pp.156-162
• /
• 2004

The spectroscopic model is proposed to analyze the gain bandwidth of a fiber Raman amplifier (FRA) with a multiple wavelength pumping scheme based on Raman gain theory. The oscillatory lineshape, which is the analytic function to analyze Raman gain spectra, allows us to estimate the gain bandwidth of the FRA. Based on the proposed theoretical modeling, we design and analyze the characteristics of the FRA using the combined multiwavelength pumping sources. We achieved the extended gain bandwidth of the FRA over 80 nm with the small gain ripple less than 0.5 dB. Threshold pumping power and effective noise figure for the FRA can be also analyzed by using the proposed model, which is also applicable for versatile fibers with other doping materials. The proposed analysis method can be useful for the design of FRA with the multiwavelength pumping scheme.