• Journal of Korean Society for Geospatial Information Science
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• v.20 no.4
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• pp.19-27
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• 2012

RUSLE(Revised Universal Soil Loss Equation) has been widely used to estimate the soil loss amount of watersheds from rainfall erosivity, soil erodibility, topographic features and cropping management condition. Rainfall erosivity is the most dominant and sensitive factor among these so that the determination of reliable rainfall erosivity is essential to estimate the soil loss of watershed. Since there has been no criterion to determine the rainfall erosivity in Korea, the empirical values, determined from the relation between the annual average rainfall and erosivity or suggested by TBR(Transport Research Board), have been used for designing the erosion control structure and controlling the soil erosion for watersheds. In this study, the procedure for estimating the rainfall erosivity using frequency analysis is proposed. The most fitted distribution function, with calculated rainfall erosivities with various frequencies and durations, has been also selected. The suggested procedure can be used to estimate the optimal value of rainfall erosivity for RUSLE in order to design soil erosion structures and control the soil erosion in watersheds effectively.

• Convergence Security Journal
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• v.5 no.2
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• pp.51-56
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• 2005

Service operating management to keep stable and effective environment according as user increase and network environment of the Internet become complex gradually and requirements of offered service and user become various is felt constraint gradually. To solve this problem, invasion confrontation system through proposed this log analysis can be consisted as search of log file that is XML's advantage storing log file by XML form is easy and fast, and can have advantage log files of system analyze unification and manages according to structure anger of data. Also, created log file by Internet Protocol Address sort by do log and by Port number sort do log, invasion type sort log file and comparative analysis created in other invasion feeler system because change sort to various form such as do log by do logarithm, feeler time possible.

• Journal of the Korean Magnetics Society
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• v.6 no.6
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• pp.367-374
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• 1996

The developmement of electronic machine industries requires miniature of size as well as increasement of driving frequency in electronic parts, recently. To realize micro-struture of magnetic devices, in this study, we fabricated thin film inductors by using thin film manufacturing techniques such as photolithography and wet etching process, and these devices are measured at high frequency range of 1 MHz~1 GHz. The results are as follows. The accurate measuring technique by using network analyzer system having microstrip line was established. The manufactured inductors are fabricated with several ten micrometers by means of wet etching process known as easier and more economic than dry etching process. VVhen the device size of two types (spiral, meander) is the same, inductance value L and quality factor Q of spiral type devices are larger than those of meander type, but driving frequency of spiral type is lower than that of meander type due to increasement of inductance L. It is necessary to decrease resistance value R by increasing cross section of the conductor film coil. Thus high frequency measuring method would be a very useful for another measuring fields of the range over several hundreds MHz.

• Polymer(Korea)
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• v.30 no.5
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• pp.437-444
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• 2006

Reactive hydroxypropyl methylcellulose phthalate (reactive HPMCP) was synthesized by using a stepwise urethane reaction with isophorone diisocyanate (IPDI) and 2-hydroxyethyl moth acrylate (HEMA). Molecular weight, acid number, and critical micelle concentration (CMC) of the synthesized reactive HPMCP and pristine HPMCP were measured and used as a polymeric surfactant in the emulsion polymerizations of styrene. In the preparation of HPMCP-hybrid poly styrene nanoparticles, 6, 9, 12, 18, and 24 wt% of HPMCPs were introduced, and the maximum rate of polymerization ($R_{p,max}$), the average number of radicals per particle (n), particle size distribution were investigated. In addition, core - shell morphology of the nanoparticles were observed by using TEM and their thermal stabilities were measured by using TGA. Reactive HPMCP showed higher $R_{p,max}$, smaller particle size, larger values of n and gel contents as compared with pristine HPMCP, due to the vinyl groups from HEMA, which can be reacted with styrene oligomers, in the reactive HPMCP.

• Polymer(Korea)
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• v.26 no.1
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• pp.1-8
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• 2002

In this study, poly(arylene ether sulfone) (PAES) having thermal stability and excellent mechanical properties was synthesized to be useful for the matrix of anion exchange resin. $1^{\circ}$-Aminated poly(arylene ether sulfone) ($1^{\circ}$-APAES) was prepared by reduction reaction after lithiation of PAES. Then $3^{\circ}$-APAES was Prepared by alkylation of the amino group of $1^{\circ}$-APAES. The structures of PAES and APAESs were confirmed with FT-IR and $^1H-NMR$ spectroscopy. Also, thermal properties of the resins were characterized by DSC and TG analysis. The introduction of amine groups in PAES resulted in the increase of glass transition temperature and decrease of initial thermal degradation temperature. The ion exchange capacities of $1^{\circ}$-APAES and $1^{\circ}$-APAES were 1.19 and 1.45 meq/g, respectively.

• Polymer(Korea)
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• v.37 no.2
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• pp.156-161
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• 2013

Phenolic antioxidants are effective stabilizers that provide excellent long-term heat stability by preventing thermo-oxidative degradation during processing and service life. However, under a selected set of circumstances, certain types of phenolics have been susceptible to discoloration due to prolonged storage in an environment containing oxides of nitrogen. It is investigated that the effect of addition of secondary antioxidant and chemical structure of primary antioxidant on discoloration of amorphous poly-${\alpha}$-olefin (APAO), which is especially prone to be decomposed in high processing temperature. From the result, it is concluded that a higher level of steric hindrance of phenolic antioxidant provided by long alkyl chain allows a more enhanced synergic effect with secondary antioxidant.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.5-11
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• 1995

In this paper, a method using a neural network was applied for the purpose of urilizing spatial features. The adopted model of neural network the three-layered architecture, and the training algorithm is the back-propagation algorithm. Co-occurrence matrix which is generated from original imge was used for imput pattern to the neural network in order to tolerate variations of patterns like rotation of displacement. Co-occurrence matrix is explained in appendix. To evaluate this method, classification was executed with this method and texture features method over the city area and sand area, which cannot be separated with the conventional method mentioned aboved. In the results of this method and texture features proposed by Haralick the method using texture features was separation rate of 67%~89%. On the contrary, the method using neural network proposed in this research was stable and high separation rate of 80%~98%.

• Polymer(Korea)
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• v.39 no.2
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• pp.293-299
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• 2015

Conductive microcellular foams consisted of polystrene (PS) and polydopamine-coated carbon nanotube (PDA-CNT) were prepared via high internal phase emulsion (HIPE) polymerization and their morphology and electrical conductivity were investigated. CNT as a conductive nanofiller was modified to PDA-CNT by coating with hydrophilic PDA on the surface of CNT to increase aqueous phase dispersion and emulsion stability. It was possible to prepare the HIPEs having higher PDA-CNT content and the resultant foams having improved conductivity due to its good dispersion. The foams showed the morphology of interconnected cell structure. As PDA-CNT content increased, yield stress and storage modulus increased and cell size reduced. The PDA-CNT content showing electrical percolation threshold was ca. 0.58 wt% and the conductivity at PDA-CNT content of 5 wt% was increased to $10^{-3}S/m$.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.131-138
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• 2008

This paper designed an Internet Convention e-Portal Information System through an experience and knowledges accumulated in case of information utilization regarding international meeting and conventions in knowledge information societies. Established the Non-stop Cluster system that was the H/W side, L4 and the applied system which was the 3-tier structure and Firewall, VPN, IDS/IPS security control system, S/W side, that utilized the WAS MVC architecture used WAS and a SOA architecture. an ASP EAI function. A user and a manager, designs and constructor, the user efficiency who were an evaluation basis of a Verification commissioner, Ubiquitous evaluated system stability. Information security anger, and evaluated former system and comparison. Therefore is evaluated to the excellent Convention e-Portal Systems that a performance 25.9% improvement consisted of compare with the existing Convention e-Portal Systems, and will contribute so as to be able to carry out-driven enemy role in development of the industrial our country Convention Ubiquitous Internet IT information Industry and International Society Conventions.

• Fire Science and Engineering
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• v.32 no.1
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• pp.76-80
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• 2018

The present study investigates the hydrodynamic force acting on the vertical wall of a portable water storage tank which has reentrant bottom topology. To numerically simulate the lapping waves in the tank, functional iterative method for the linearized Peregrine's model which numerically simulates the propagating waves over the slowly-sloped bottom topology is introduced. The numerical experiment condition is controlled to adjust the position and the height of the water supplying nozzle. Finally, it is observed that the maximum wave height at the vertical wall and the ratio of hydrodynamic force to hydrostatic one are amplified accordingly. Therefore it must be give attention to this bad effect of amplified hydrodynamic force by the supply method of fire water in order to have the structural stability of the portable water storage tank when it was used on the reentrant bottom topography.