• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.664-674
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• 2001

In this paper, as a new category of fuzzy-neural networks architecture, we propose Fuzzy Polynomial Neural Networks (FPNN) and discuss a comprehensive design methodology related to its architecture. FPNN dwells on the ideas of fuzzy rule-based computing and neural networks. The FPNN architecture consists of layers with activation nodes based on fuzzy inference rules. Here each activation node is presented as Fuzzy Polynomial Neuron(FPN). The conclusion part of the rules, especially the regression polynomial, uses several types of high-order polynomials such as linear, quadratic and modified quadratic. As the premise part of the rules, both triangular and Gaussian-like membership functions are studied. It is worth stressing that the number of the layers and the nods in each layer of the FPNN are not predetermined, unlike in the case of the popular multilayer perceptron structure, but these are generated in a dynamic manner. With the aid of two representative time series process data, a detailed design procedure is discussed, and the stability is introduced as a measure of stability of the model for the comparative analysis of various architectures.

• Carbon letters
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• v.15 no.3
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• pp.192-197
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• 2014

A hierarchical pore structured novolac-type phenol based-activated carbon with micropores and mesopores was fabricated. Physical activation using a sacrificial silicon dioxide ($SiO_2$) template and chemical activation using potassium hydroxide (KOH) were employed to prepare these materials. The morphology of the well-developed pore structure was characterized using field-emission scanning electron microscopy. The novolac-type phenol-based activated carbon retained hierarchical pores (micropores and mesopores); it exhibited high Brunauer-Emmett-Teller specific surface areas and hierarchical pore size distributions. The hierarchical pore novolac-type phenol-based activated carbon was used as an electrode in electric double-layer capacitors, and the specific capacitance and the retained capacitance ratio were measured. The specific capacitances and the retained capacitance ratio were enhanced, depending on the $SiO_2$ concentration in the material. This result is attributed to the hierarchical pore structure of the novolac-type phenol-based activated carbon.

• Journal of Aerospace System Engineering
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• v.10 no.2
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• pp.1-6
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• 2016

The thermal analysis of electronic equipment is required to predict the reliability of electronic equipment being loaded on a satellite. The transient heat transfer of electronic equipment that was developed recently has been generated using a large-scale integration circuit. If there is a transient heat transfer between EEE(Electric, Electronic and Electro mechanical) parts, it may lead to failure the satellite mission. In this study, we performed the thermal design and analysis for reliability of APD(Antenna Pointing Driver) electronics for activation of a spaceborne X-band 2-axis antenna. The EEE parts were designed using a thermal mathematical model without the thermal mitigation element. In addition, thermal analysis was performed based on the worst case for verifying the reliability of EEE parts. For the thermal analysis results, the thermal stability of electronic equipment has been demonstrated by satisfying the de-rating junction temperature.

• Polymer(Korea)
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• v.29 no.5
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• pp.508-517
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• 2005

The thermal degradation behavior and reliability analysis were investigated using dynamic thermogravimetric analysis (TGA) and accelerated degradation test (ADT) to characterize the dynamic parameters related to thermal degradation of plastic meterials for household electric appliances. In addition, the weathering of the plastic were performed by ADT using Xenon uc, and the color difference of the samples after ADT were measured with Color Eye 3010 specoophotometer. he activation energy for thermal degradation of the samples increased with increasing the rate of weight loss. The Kim-Park method was found to be more effective analysis in describing thermal degradation of plastic meterials. Plastic materials were very sensitive to ultra-violet rays in faster degradation.

• Carbon letters
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• v.1 no.3_4
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• pp.133-137
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• 2001

Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.397-400
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• 1996

We investigated electric and dielectric properties of MIM device using Maleate Copolymer LB films. The thickness of maleate copolymer LB film by ellipsometry measurements and X-ray diffraction pattern was about 27~30[ ]. The maleate copolymer 13 film have the property of insulator like organic ultra-thin film. The electric conduction was Schottky current measured by I-V characteristics, and the conductivity was 10$^{-15}$ ~10$^{-14}$ [S/cm]. Dielectric constant was about 5.0~6.0 by various measurement: I-V, frequency-depenent dielectric properties. Schottky barrier was about 0.9 ~1.0(eV). By relation between log I and 1/T, activation energy baa 0.74(eV). Frequency-depenent dielectric properties wart orientational polarization by the dipole.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.819-826
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• 2003

This article is concerned with the overview of activated carbons as electrode materials in electric double-layer capacitors. Firstly, this article introduced various types of activated carbons with their precursors and manufacturing conditions which can be divided into two main steps of the carbonization and activation processes. Secondly, the present article gave the detailed discussion about the porous structures and examined previous works on the electrochemical behaviors of activated carbons in relation to their porous structures, along with our recent works. Finally, this article characterized the surface oxygen functional groups and presented their influence on the electrochemical properties of activated carbons by reviewing our recent results.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.58-67
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• 2010

Combustion of the Korean Anthracite and wood-pellet was characterized in air atmosphere with variation of heating rate(5, 10, 20 and $30^{\circ}C/min$) in TGA. The results of TGA have shown that the combustion of the wood-pellet occurred in the temperature range of $200{\sim}620^{\circ}C$ which is much lower than that of Korean anthracite. Activation energies of the wood-pellet and Korean anthracite, determined by using Friedman method were 44.12, 21.45 kcal/mol respectively. Also, their reaction orders(n) and pre-exponential factors(A) were 5.153, 0.7453 and $4.01{\times}10^{16}$, $1.39{\times}10^6(s^{-1})$ respectively. In order to find out the combustion mechanism of the wood-pellet and Korean anthracite, twelve solidstate mechanisms defined by Coats Redfern Method were tested. The solid state combustion mechanisms of the woodpellet and Korean anthracite were found to be sigmoidal curve A3 type and a deceleration curve F1 type respectively. Also, from iso-thermal combustion($300{\sim}900^{\circ}C$) of their char, the combustion characteristics of their char was found. Activation energies of the their char were 27.5, 51.2 kcal/mol respectively. Also, pre-exponential factors(A) were $2.55{\times}10^{12}$, $1.49{\times}10^{10}(s^{-1})$ respectively. Due to the high combustion reactivity of wood-pellet compared with Korean anthracite, combustion atmosphere will be improved by co-combustion with Korean anthracite and wood-pellet.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.395-398
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• 2001

Recently, the increasing need for internet and the activation of hiring business of communication line makes the demand for OPGW cable which can construct the optical communication network in the basis of existing overhead power transmission line. Especially, the demand is focused on the high fiber count OPGW due to high capacity transmission. In step with the trend toward high fiber count cable we have developed the Stainless Steel Loose Tube type OPGW within which have 144core firstly in KOREA. This paper describes the cable design and manufacturing process which gives the stable operation in very severe conditions and the long-term reliability test results conducted in according to dominant specification IEEE Std. 1138-1194.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1388-1392
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• 2013

Electric scooter has been using short-lived, low-efficiency DC motor. And motor control system is equipped with imported uniformly, so there is no product differentiation. Also, product design according to the characteristics of disability is difficult. In this study, BLDC motor control system to specialize in a electric scooter for disabled was developed with a semi-permanent features of life, low price, and high performance. This development will also contribute to the activation of the related industries, as well as be able to secure price competitiveness of domestic electric scooter.