• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.267-270
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• 2002

Photodissociations of o-, m-, and p-iodotoluene radical cations were investigated by using Fourier-transform ion cyclotron resonance (FT-ICR) spectrometry. Iodotoluene radical cations were prepared in an ICR cell by a photoionization charge-transfer method. The time-resolved one-photon dissociation spectra were obtained at 532 nm and the identities of $C_7H_7^+$ products were determined by examining their bimolecular reactivities toward toluene-$d_8$. The two-photon dissociation spectra were also recorded in the wavelength range 615-670 nm. The laser power dependence, the temporal variation, and the identities of $C_7H_7^+$ were examined at 640 nm. The mechanism of unimolecular dissociation of iodotoluene radical cations is elucidated: the lowest barrier rearrangement channel leads exclusively to the formation of the benzyl cation, whereas the direct C-I cleavage channel yields the tolyl cations that rearrange to both benzyl and tropylium cations with dissimilar branching ratios among o-, m-, and p-isomers. With a two-photon energy of 3.87 eV at 640 nm, the direct C-I cleavage channel results in the product branching ratio, [tropylium cation]/[benzyl cation], in descending order, 0.16 for meta >0.09 for ortho >0.05 for para.

• Toxicological Research
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• 제11권1호
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• pp.57-62
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• 1995

To investigate the ultrastructural changes of kidney and clarify to a cause of its changes in lead intoxicated rats, the 0.5% lead acetate administed orally to the rats and those were sacrifled at 2 day, 1, 2, 4, 6 and 8 week after the treatment of lead acetate. Each extirpated kidney was histopathologically examined under the electron microscopy and histochemical examination was also carried out. Concomitantly, the activity of free radical metabolizing enzyme was determined. The blood levels of lead concentration showed a gradual increase from the first group reaching the plateau at the one or two week group with the slightly decreasing value throughout the whole course of the experiment. And the urinary ALA concentration showed a gradual increase from the first group to the 8 week group. In the kidney tissue of rat sacrified at 6 week, the proximal tubular cells showed dilatation of endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies on electron microscope and oxygen free radicals are identified by histochemistry on light microscope whereas there were no differences in the activity of catalase and glutathione peroxidase between the lead acetate treated group and control group. But the activity of xanthine oxidase was more increased in lead acetate treated rats than control group. Furthermore, the superoxide dismutase activity was significantly increased in the experimental group than the control group. In conclusion, it is assumed the kidney damage in lead intoxicated rat may be induced by free radicals.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.299-301
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• 2017

최근 다양한 산업들이 IT기술과 융합되어 비즈니스 환경이 변화하고, 핵심자산이 정보화됨에 따라 기업정보 유출의 위험성이 높아지고 있다. 이러한 유출 사건 사고는 끊임없이 증가하고 있기 때문에, 선행적으로 기업정보를 보호할 수 있는 보안환경이 구축되어야 한다. 이에 따라 기업정보 보안기술에 대한 연구와 투자는 꾸준히 증가하고 있으며, 다양한 보안 시스템이 개발되고 있다. 그러나 기업정보 보안기술에 대한 적절한 구분이 되어있지 않아 보안 시스템들이 서로 중복된 기능을 수행하고 있다. 중복된 기능의 보안 시스템 사용은 비용을 낭비할 뿐만 아니라, 효율적인 보안 관리를 하지 못하게 되는 문제가 발생한다. 따라서 본 논문에서는 이러한 문제점을 해결하고 균형 잡힌 기업정보 보안 시스템의 발전을 위해 선행연구를 통해 기업정보 보안 시스템에 관한 분류체계를 설계하였다. 향후 이 분류체계를 기반으로 메타분석을 실시하여, 그동안 진행된 기업정보 보안 시스템 분야에 대한 연구동향을 파악하고 학술적으로 연구자들에게 연구 방향성을 제시하고자 한다.

• 경영과학
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• 제28권1호
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• pp.1-10
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• 2011

One of the fundamental roles of web object navigation is to support what the user wants precisely and efficiently from the enormous web database to the web browser. As long as the web search results are a set of individual lists, it is all right to display each and every web result for the web browser to display a web object one by one. However, in case the search results are a collection of multiple interrelated web objects, then there is a need to represent for a new mechanism for linked web objects at a time. We define a unit of web objects derived from a Steiner tree where the web objects include a set of specific keywords calculated by the weight from which the solutions are extracted. Even if a web object does not include all the keywords, then the related hypertext linked web objects are derived and displayed onto the mobile web browser with meta data in one shot. In this paper, it is applied for the mobile browser that the web contents can dynamically be displayed with Steiner trees until each renewal of the navigation request may be issued. In this paper, a new synchronized mobile browsing method is developed so that the navigating time can drastically be reduced and the web navigating efficiency can be dramatically enhanced without sacrificing memory consumption.

• 한국문헌정보학회지
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• 제47권3호
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• pp.139-160
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• 2013

국내의 교육정책정보서비스를 제공하는 교육정책당국, 전문 연구기관과 전문사이트의 10개 웹사이트를 선정하여 내용분석법의 방법으로 이들이 제공하는 주요 정책정보의 종류, 분류체계, 검색시스템의 정보검색 기능 등을 중심으로 분석하였다. 비교 분석한 결과 제시된 문제점을 검토하여 표준화된 교육정책정보 분류체계 개발, 교육정책정보원의 메타데이터 표준화와 검색시스템의 편의성 제고, 정책당국 밀착형 맞춤서비스 제공, 분야별 정책정보 전문센터 운영, 정책분야 간 협력체제 구축을 개선점으로 제안하였다. 또한, 교육정책정보원, 교육정책정보시스템, 운영체제, 협력체제로 구성된 교육정책정보전문센터 모형을 제시하였다.

• 자원환경지질
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• 제29권2호
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• pp.159-170
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• 1996

The gold-silver deposits of the Nakcheon, Eunchi and Jungbong mine in the northern Taebagsan mining district are composed of fissure fil1ing veins emplaced in Precambrian meta-sediments and Jungbongsan granite. Based on the changes of ore texture and mineralogy, ore mineral chemistry, fluid inclusion and mineralizing condition, a regional zoning is recognized from the Nakcheon to the Eunchi and Jungbong ore deposits, and this trend of zoning is also recognized by stable isotope compositions. Stable isotope compositions show that the source of su1fur and carbon is mainly igneous origin, and the water of ore fluid in the Nakcheon ore deposits is mainly magmatic origin but much of meteoric water is involved in ore fluid of the Eunchi and Jungbong ore deposits. The ore deposits of study area is polymetallic meso to epithermal type genetically related to the acidic igneous pluton. Due to the differntial erosion level and mineralized depth, each ore deposits has a slightly different characteristic of mineralization; The Nakcheon ore deposits belong to meso-epithermal type, but the Eunchi and Jungbong ore deposits belong to epithermal type.

• 한국환경복원기술학회지
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• 제20권6호
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• pp.133-149
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• 2017

As cities face increasing problems such as aging, environmental pollution and growth limits, we have been trying to incorporate sustainability into urban planning and related policies. However, it is very difficult to generate a 'sustainable spatial plans' because there are trade-offs among environmental, society, and economic values. This is a kind of non-linear problem, and has limitations to be solved by existing qualitative expert knowledge. Many researches from abroad have used the meta heuristic optimization algorithms such as Genetic Algorithms(GAs), Simulated Annealing(SA), Ant Colony Optimization(ACO) and so on to synthesize competing values in spaces. GAs is the most frequently applied theory and have been known to produce 'good-enough plans' in a reasonable time. Therefore we collected the research on 'spatial optimization model based GAs' and analyzed in terms of 'study area', 'optimization objective', 'fitness function', and 'effectiveness/efficiency'. We expect the results of this study can suggest that 'what problems the spatial optimization model can be applied to' and 'linkage possibility with existing planning methodology'.

• Advances in Energy Research
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• 제4권4호
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• pp.255-274
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• 2016

This paper presents a novel symbiotic organisms search (SOS) algorithm to optimize both real power loss (RPL) and voltage stability limit (VSL) of a transmission network by controlling the variables such as unified power flow controller (UPFC) location, UPFC series injected voltage magnitude and phase angle and transformer taps simultaneously. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained multi objective, multi variable optimization problem with a fitness function integrating both RPL and VSL. The symbiotic organisms search (SOS) algorithm is a nature inspired optimization method based on the biological interactions between the organisms in ecosystem. The advantage of SOS algorithm is that it requires a few control parameters compared to other meta-heuristic algorithms. The proposed SOS algorithm is applied for solving optimum control variables for both single objective and multi-objective optimization problems and tested on New England 39 bus test system. In the single objective optimization problem only RPL minimization is considered. The simulation results of the proposed algorithm have been compared with the results of the algorithms like interior point successive linear programming (IPSLP) and bacteria foraging algorithm (BFA) reported in the literature. The comparison results confirm the efficacy and superiority of the proposed method in optimizing both single and multi objective problems.

• Advances in Computational Design
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• 제2권4호
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• pp.313-331
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• 2017

In this study, teaching-learning based optimization (TLBO) is improved by incorporating model of multiple teachers, adaptive teaching factor, self-motivated learning, and learning through tutorial. Modified TLBO (MTLBO) is applied for simultaneous topology, shape, and size optimization of space and planar trusses to study its effectiveness. All the benchmark problems are subjected to stress, displacement, and kinematic stability constraints while design variables are discrete and continuous. Analyses of unacceptable and singular topologies are prohibited by seeing element connectivity through Grubler's criterion and the positive definiteness. Performance of MTLBO is compared to TLBO and state-of-the-art algorithms available in literature, such as a genetic algorithm (GA), improved GA, force method and GA, ant colony optimization, adaptive multi-population differential evolution, a firefly algorithm, group search optimization (GSO), improved GSO, and intelligent garbage can decision-making model evolution algorithm. It is observed that MTLBO has performed better or found nearly the same optimum solutions.

• 한국항행학회논문지
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• 제13권5호
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• pp.781-786
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• 2009

클라우드 컴퓨팅 환경은 웹을 기반으로 한 응용분야의 새로운 트랜드이다. 이는 많은 사용자들이 쉽게 인터넷을 통해 자원을 할당받고 서비스를 지원받을 수 있는 IT 비즈니스 모델이라 할 수 있다. 또한 u-러닝은 인터넷 기반 학습의 효율성을 극대화한 모델이다. 따라서 본 연구는 이를 인터넷 기반 학습에 응용하는 u-러닝 교수 학습 모형의 설계를 제시하고자 한다. 제안된 교수 학습 모형은 u-러닝에 맞도록 준비, 계획, 수집, 학습 진행, 분석 및 평가, 피드백의 7단계로 구성하였다. 이는 클라우드 u-러닝 서버와 클라우드 LMS를 두어 처리 및 관리하도록 하였으며, 학습자의 이동형 기기 모델의 인식을 위하여 이동형 기기 메타데이터를 두도록 하였다.