• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.157-162
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• 2011

International Telecommunication Union(ITU), recommended a propagation prediction models that can be applied to a various propagation environments that many services have been established in the field of broadcasting and telecommunications using ITU-R. Each propagation prediction models are revised with the complement procedures of an expected difference of channel environment and prepared for a standard of a propagation prediction. In this research, it is possible to realized a practical propagation prediction in each transmitting station for a broadcasting environments of ITU-R Rec. P.1546-3 model, so called the point-to-area, using supplementary parameters of the transmitting station specification.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.17-25
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• 2021

When a person wears clothing, it is important to configure an outfit appropriate to the intended occasion. Therefore, T.P.O(Time, Place, Occasion) of the outfit is considered in various fashion recommendation systems based on artificial intelligence. However, there are few studies that directly infer the T.P.O from outfit images, as the nature of the problem causes multi-label and class imbalance problems, which makes model training challenging. Therefore, in this study, we propose a model that can infer the T.P.O of outfit images by employing a label-distribution-aware margin(LDAM) loss function. Datasets for the model training and evaluation were collected from fashion shopping malls. As a result of measuring performance, it was confirmed that the proposed model showed balanced performance in all T.P.O classes compared to baselines.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.544-551
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• 2008

QUAL2K enhanced QUAL2E and applied in real fields efficiently incorporates denitrification process, sediment-water interaction process, bottom algae and detritus. Also, the CBOD of QUAL2K is divided into two real parts, one is slow CBOD(sCBOD) and another is fast CBOD(fCBOD). The simulation results of QUAL2E and QUAL2K models in Anyang Stream were compared and analyzed in water quality constituents of DO, BOD, Org-N, NH$_3$-N, NO$_3$-N, Org-P, Dis-P and Chl-a respectively. The similar results were shown in Org-N, NH$_3$-N, Org-P and Chl-a both QUAL2K and QUAL2E models. But the different results were revealed in DO, BOD, Dis-P and NO$_3$-N by the influence of new incorporating processes. DO was shown relatively low values in the effect of bottom algae. BOD which is influenced by particulate organic matter was revealed high values. NO$_3$-N was closed to the real values by the two processes of denitrification and sediment-water interaction. To evaluate the running results of QUAL2K and QUAL2E models, a simple statistical analysis was conducted. According to the statistical analysis, QUAL2K represented less relative error and coefficient of variation than QUAL2E in almost all of constituents. It was found that QUAL2K, which simulates the water quality more realistically, can be applied to control and manage the water problems of river or river-run reservoir effectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.419-425
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• 2014

The current work investigated the variation of numerical solutions according to the grid number, the distance of the first grid point off the ship surface, turbulence modeling and discretization. The subject vessel is KVLCC. A commercial code, Gridgen V15 and FLUENT were used the generation of the ship hull surface and spatial system and flow computation. The first part of examination, the effect of solutions were accessed depending on the grid number, turbulence modeling and discretization. The second part was focus on the suitable selection of the distance of the first grid point off the ship surface: $Y_P+$. When grid number and discretization were fixed the same value, the friction resistance showed differences within 1 % but the pressure resistance showed big differences 9 % depending on the turbulence modeling. When $Y_P+$ were set 30 and 50 for the same discretization, friction resistance showed almost same results within 1 % according to the turbulence modeling. However, when $Y_P+$ were fixed 100, friction resistance showed more differences of 3 % compared to $Y_P+$ of 30 and 50. Whereas pressure resistance showed big differences of 10 % regardless of turbulence modeling. When turbulence modeling and discretization were set the same value, friction, pressure and total resistance showed almost same result within 0.3 % depending on the grid number. Lastly, When turbulence modeling and discretization were fixed the same value, the friction resistance showed differences within 5~8 % but the pressure resistance showed small differences depending on the $Y_P+$.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.35-42
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• 2007

We describe the problem of reducing the key material in the Even-Mansour cipher without security degradation. Even and Mansour proposed a block cipher based on XORing secret key material just prior to and after applying random oracle permutation P such that $C=k_2\bigoplus P(M\bigoplus k_1)$. Recently, Gentry and Ramzan showed that this scheme in the random permutation oracle can be replaced by the four-round Feistel network construction in the random function oracle and also proved that their scheme is super-pseudorandom. In this paper we reduce the key size from 2n to n, which is the optimal key size of Even-Mansour cipher in the random function oracle model and also give almost the same level of security.

• Journal of Science Education
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• v.42 no.2
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• pp.132-147
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• 2018

The goal of this research is to suggest a theoretical process-centered assessment model based on Learning Progressions of key competencies in the context of STEAM instructions. The "Process-Products Combined Module-type (P2CM) STEAM Assessment Model (P2CM STEAM Assessment Model, hereafter) can be used both as an instructional model and as an assesment model, applicable for various STEAM topics and instructional types. consists of 3 axes. The first X axis stands for 4C competencies that should be emphasized through STEAM instruction. The second Y axis stands for the types and the hierarchy of STEAM instructions. The third Z axis stands for the assessment standards based on LP. We also exemplified an assessment module combined creativity competency with creativity-based instruction based on . Based on the research results, we suggested elaboration of assessment models based on Korean LP research outcomes, development and supply of formative assessment models through field-based in-depth research, modification of formative assessment models with the participation of teacher communities and in-service teachers, and the necessity of further research on assessment models for tracking LP.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.177-185
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• 1996

Four types of experiments were performed to check the similitude of member behavior between prototype and 1 /10 scale models : (1) Test of slender columns with P-$\Delta$ effect, (2) Test of short columns with and without confinement steel, (3) Test of simple beams without stirrups, and (4) 'T-beam test. Based on the results of experiments, the conclusions were made as follows : (1) The P-$\Delta$ effect of slender columns can be almost exactly represented by 1/10 scale model. (2) The effect of confinement on short columns by the hoop steel can be also roughly simulated by 1/10 scale model. (3) The failure modes of simple beams without stirrups are brittle shear failures in prototype whereas those of 1/10 scale models are the ductile yielding of tension steel followed by large diagonal tension cracking and compressive concrete failure. (4) The behaviors of prototype and 1/10 scale model in T-beams appear very similar.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.230-233
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• 2010

최근 분산된 노드들 간의 자료를 송수신하는 임베디드 어플리케이션들이 증가함에 따라 이를 지원하기 위한 분산 미들웨어도 함께 발전하고 있다. 분산미들웨어는 원격 객체 관리를 위한 클라이언트-서버 모델, 큐를 이용한 메시지 전송을 목적으로 하는 메시지 패싱 모델, 분산 컴퓨팅 환경에서 자료의 전송을 목적으로 하는 출판-구독 모델이라는 3가지 모델로 분류 된다. 본 논문에서는 3가지 분산 미들웨어 모델들에 대하여 살펴보고 출판-구독 모델의 대표적 분산미들웨어인 Data Distribution Service를 소개한다. 또한 출판-구독 모델이 단말 간 P2P를 지원함에 따라 생기는 문제점인 과다한 트래픽을 해결하기 위해 자료들을 그룹화 시켜 전송하거나 특정 토픽에 관련된 자료들을 미리 예약된 채널을 통해 전송하는 기법들을 제안하고 일반 DDS와 비교를 통해 그 효과를 예측해본다.

• Journal of the Mineralogical Society of Korea
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• v.17 no.2
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• pp.157-168
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• 2004

The surface chemical properties of aqueous kaolinite and halloysite were studied using a potentiometric titration experiment and a computer program FITEQL3.2. Among the surface complexation models a constant capacitance model was selected for this study. The 2 sites - 3 p $K_{a}$ s model, in which the surfaces were assumed to have tetrahedral and octahedral sites, was reasonable for the description of the experimental data. The surface charges of both minerals were negative above pH of 4. The higher the pH, the lower the proton surface charge densities of both minerals. The ≡ $SiO^{[-10]}$ site played an important role in cation adsorption in acid and neutral pH range; whereas the ≡ Al $O^{[-10]}$ site was in an alkaline pH range. The optimized intrinsic constants of kaolinite, p $K_{a2(Si)}$$^{int}$, p $K_{al(Al)}$$^{int}$ and p $K_{a2(Al)}$$^{int}$ were 4.436, 4.564, and 8.461 respectively, and those of halloysite were 7.852, 3.885, and 7.084, respectively. The total Si and Al surface sites concentrations of kaolinite were 0.215 and 0.148 mM, and those of halloysite were 0.357 and 0.246 mM. The ratio of Si and Al surface site densities ([≡SiOH]:[≡AlOH]) of both minerals was 1 : 0.69. The total surface site density of kaolinite, 3.774 sites/n $m^2$, was 1.6 times larger than that of halloysite, 2.292 sites/n $m^2$./TEX>.

• Computational Structural Engineering
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• v.7 no.3
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• pp.105-113
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• 1994

Precast concrete(P.C.) large panel structures have usually weaker stiffness at joints than that of monolithic in-situ reinforced concrete structures. But structural designers do not in general take into account this characteristics of P.C. large panel structures and use the same analytical models as for the monolithic structure. Therefore, the results of analysis obtained by using these models may be quite different from those actually occurring in real P.C. structure. In this study, the change in force and stress distribution and deflections of structure caused by applying lower shear stiffness at vertical joints are investigated through trying several finite element modeling schemes specific for P.C. structures, Finally, for engineers in practice, a simplified model, which takes account of the effect of lower shear stiffness at vertical joints, is proposed with the understanding on possible amount of errors.