• Journal of Korean Society of Transportation
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• v.8 no.1
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• pp.89-102
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• 1990

본 연구에서는 개별모형(disaggregate model)을 이용한 도시권의 교통수요예측 모형체계의 구축을 최종목적으로 하며, 그때 개인이 1일 중에 행하는 복수의 트립에 관한 의사결정간의 상호관계를 적절히 고려함에 의해, 되도록 개인의 교통행동을 논리적으로 설명함과 동시에 모형의 취급이 용이하도록 논리성과 실용성이 잘 조화된 모형의 구축을 시도하였다. 모형의 체계는 비취업자와 취업자 각각의 1일의 통행행태유형의 선택에 관한 2개의 Sub-model로 구성되어져 있다. 본 논문은 그 Sub-model중의 하나인 비취업자의 1일의 통행행태유형(트립발생, 각 트립의 목적지와 교통수단)의 선택에 관한 개별모형의 개발을 행한 것이다. 본 모형의 특징은 tour별 효용최대화행동가설에 기초를 두어 개인이 1일 중에 행하는 각 트립의 선택행동은 해당트립의 전후에 행해지는 트립들의 선택행동의 영향을 고려하여 의사결정을 하는 것으로 가설을 설정하여 트립간의 상호관련성을 표현하였다. 모형의 구조로서는, 모형의 취급이 보다 용이하도록 tour별 효과최대화를 트립단위의 단계형 모형으로 표현하는 nested logit model형의 수차동시효과최대화 모형을 구축하였다 실제의 도시권에 대한 실증적 검토를 행한 결과, 본 연구에서 개발한 별개모형의 유효성이 확인되었다.

• NEWSLETTER 전기공업
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• no.96-7 s.152
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• pp.12-37
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• 1996

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.543-548
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• 1996

이 연구의 목적은 고리 3/4호기 및 영광 1/2호기의 음의 중성자속 변화율에 의한 원자로 트립(NFRT) 설정치를 제거하여 불의의 제어봉 낙하 사고시에 원자로 트립을 방지하는 것이다. 현재의 인허가된 안전해석 방법론에 의하면 제어봉 낙하사고시에 NFRT에 의하여 원자로가 트립되고 결국 발전소의 이용율이 감소하게 되는데 본 연구에서 적용된 새로운 방법론으로는 이 NFRT 보호신호 없이도 제어봉 낙하사고시에 발전소의 안전성을 입증할 수 있다. 안전분석은 주기별로 다른 핵설계 자료 즉, 냉각재 온도상수, 전출력에서의 제어봉가 및 제어봉 삽입한계 등을 이용하여 수행되었다. 웨스팅하우스형 연료인 OFA 및 V5H에 대하여 고리 4호기 6주기외 3개 주기에 대하여 분석되었다. 분석된 주기들에 대해서 NFRT 신호 없이도 핵비등 이탈률(DNBR) 설계기준을 모두 만족하였다. 그러므로 고리 3/4호기 및 영광 1/2호기의 NFRT 신호는 제거할수 있고 이로써 제어봉 낙하사고시의 발전소 불시정지를 방지할수 있다.

• Journal of Life Science
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• v.24 no.4
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• pp.437-446
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• 2014

Problems appear when triptans are taken orally. For example, the bioavailability of triptan is reduced by the digestive system, and the drug level in the blood reduces rapidly over time; there is also a possibility of gastrointestinal disorder. To improve side effects, a transdermal patch has been prepared in hydrogel form. The polymer matrix that makes up the hydrogel uses PVA; PEG is used as an additive to induce inter/intra hydrogen bonding of the PVA and almotriptan drug is added. In addition, to accelerate micro-phase separation between PVA chains, liquid nitrogen is used. In FT-IR analysis, the absorption bands of PVA, PEG, and almotriptan were found. The degree of crystallinity, the water uptake ability and tensile strength were increased with increasing PEG content. In drug release tests, the amount of drug released increased depending on the PEG content. In this study, hydrogels with 10 wt% PEG showed better performance in drug release. Approximately 60% of the total drug amount was released in 2 hr, and the drug continued to release for 1 day. Thus, the prepared hydrogel patch is suitable as a transdermal formulation for the second dose administration of triptans to patients who require recurrent migraine treatment within 24 hr after the first administration.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.603-608
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• 2005

The molded macroporous poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) rods produced by a facile molding process were polymerized in situ within a tubular mold, chromatographic column ($4.6{\times}100mm$) by free radical polymerization. It was complemented by epoxy derivatized monolithic column and chemical modification of the epoxide groups with the sulphuric acid. By variation of the polymerization conditions, such as the ratio of the monomers, the porogen (pore generating material), and the temperature, the pore size could be varied, so the retention time of the samples may be adjusted. For the mixture of caffeine and tryptophan in the prepared monolithic column, the influences of polymerization material compositions to the efficiency, selectivity, and resolution of the monolithic column were investigated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1767-1773
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• 1993

In this paper, the coupling characteristics as well as the self and the mutual Impedance of a two-element probe-fed stacked circular microstrip array antennas are presented. A full wave analysis for the structure is performed In the spectral domain using the vector Hankel transform(VHT). Also, we presented measured results for the impedance, the coupling characteristics of the antenna and the variation of the coupling with the distance between the two elements. Finally, the calculated and measured results are shown to agree well wlth each other through comparisons.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.26-35
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• 1996

In this paper, characteristics of the electromagnetically coupled broadband microstrip antennas are analyzed by the Finite Difference Time Domain (FDTD) method, and antenna para- meters are optimized to get maximum bnadwidth. By using short radial tuning stub in microstrip feedline, electromagnetically coupled microstrip antenna shows broadband ($\simeq$13%) characteristics, and the characteristics are varied as a function of radius, radial angle, and position of the radial tuning stub. Operating frequency, return loss, VSWR and input impedance are calculated by Fourier transforming the time domain results. After optimization of the parameters, maximum bandwidth of the radial stub tuning microstrip antenna is about 15% and the ripple char- acteristic of the VSWR is better than the rectangular tuning stub microstrip antenna.

• KSBB Journal
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• v.21 no.5
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• pp.401-404
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• 2006

Macroporous Poly(Methacrylic acid-co-Ethylene Glycol Dimethacrylate) Rods were in situ thermal initialized within a empty column($3.9{\times}150mm$) by free radical polymerization. The polymerization mixture was consisted of monomer, cross-linking monomer, porogenic solvent, initiator and control the ratio of these materials, column efficiency could be developed. Caffeine and tryptophan as separation substances and the retention mechanism of this kind of monolithic column was mainly hydrogen bond function.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.925-933
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• 1991

Caracteristics of cylindrical rectanyular patch microshtrip resonator are analyzed by cavity model. To minimize the error of resonant frequency due to fringing field, the resonant frequency is calcylated by the concept of effective dielectric constant. The transmisson type resonator operating at 3GHz is designed and manufactured. The measured data of the resonant frequency and reflection loss are 3.019Ghz and \ulcorner32.78dB respectively. These results nearly coincide with theoretical results.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.527-532
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• 2012

Recently, in power system, even though the needs of protective IED(Intelligent Electronic Device) is highly increased, there are some problems in the field when use the IED. When the IED is in the fluctuated overload condition, because of the existing algorithm calculate the trip time only with the measured current of just previous measuring stage, the calculated trip time is not a proper value for the overload protection at this kind of condition, and when the load current fluctuate between overload and normal condition, because of the instantaneous reset characteristic of existing algorithm the IED dose not trip. And the non linear loads using power electronic elements seem to be increased. These non linear loads require a counterplan about various harmonics incoming to electric power systems. So we will give solutions about these problems.