• Communications of the Korean Mathematical Society
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• v.21 no.4
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• pp.701-717
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• 2006

The positive coexistence of a simple food chain model with ratio-dependent functional response and cross-diffusion is discussed. Especially, when a cross-diffusion is small enough, the existence of positive solutions of the system concerned can be expected. The extinction conditions for all three interacting species and for one or two of three species are studied. Moreover, when a cross-diffusion is sufficiently large, the extinction of prey species with cross-diffusion interaction to predator occurs. The method employed is the comparison argument for elliptic problem and fixed point theory in a positive cone on a Banach space.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.66-69
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• 2000

In order to analyze the densification behaviour of stainless steel powder compacts during hot isostatic pressing (HIP) at elevated temperatures, a power-law creep constitutive model based on the plastic deformation theory for porous materials was applied to the densification. Various densification mechanisms including interparticle boundary diffusion, grain boundary diffusion and lattice diffusion mechanisms were incorporated in the constitutive model, as well. The power-law creep model in conjunction with various diffusion models was applied to the HIP process of 316L stainless steel powder compacts under 50 and 100 MPa at 1125 $!`\acute{\dot{E}}$. The results of the calculations were verified using literature data It could be found that the contribution of the diffusional mechanisms is not significant under the current process conditions.

• Knowledge Management Research
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• v.9 no.3
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• pp.77-105
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• 2008

This study primarily aims at identifying what factors significantly affect the diffusion of knowledge management systems(KMS) and finding out how these identified factors can be effectively managed, especially for Korean companies. The research model is derived based on previous researches on innovation diffusion, information systems implementation, and KMS. The model is used to examine the role of determinants in influencing the extent to which KMS is diffused within organizations. Independent variables of this research are composed of technical characteristics, organizational characteristics and environmental characteristics. 'Breadth of diffusion' and 'depth of diffusion' concept are used to measure the extent of KMS diffusion which is the dependent variable of this model. The 101 companies of total 1,000 samples responded to the survey. To analyze tile results of this empirical study, we performed the multiple regression analysis. As a result, it was shown that the relative advantage, complexity, information system maturity, size, top management support, champion, competitive pressure have influences on both the breadth and the depth diffusions. On the other hand, the organizational culture, valuation and compensation, and uncertainty of environmental factors were not verified to be significant. This empirical study will provide Korean companies with insights into effective ways to diffuse the KMS and succeed in business competition.

• International Journal of Contents
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• v.15 no.2
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• pp.1-12
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• 2019

Despite their various similarities, Seoul's' Gangnam and Seocho districts showed different patterns in the adoption of the RFID household-based waste charging system. Gangnam, one of the 25 wealthiest districts in Seoul, first adopted the RFID system in 2012, but decided abandon it a year later due to inconvenience, sanitation, budget limitations, and management related issues. Unlike Gangnam, Seocho, a largely similar district to Gangnam, started to implement the RFID system in 2015 and successfully adopted this innovation. In this paper, we explain the adoption behaviors of these two districts using a Technology Hype Curve Model with 5 stages. Unlike traditional technology adoption theory, the Hype Curve Model concentrates on the big chasm between early majorities and late majorities, which is a core reason for discontinuity in innovation diffusion. Based on our case study result, the early majority easily gave up adoption due to immature technological and institutional infrastructure. However, Seocho district, who waited until the deficiencies had been sufficiently fixed since late majorities, succeeded at incremental diffusion. Since its invention by Gartner cooperation, the Hype Curve Model has not received enough attention in academia. This paper demonstrates its explanatory power for innovation diffusion. Similarly, this paper focuses on the importance of institutional framework in the diffusion of innovation. Lastly, we compare the behavior of two local governments in supporting and diffusing RFID systems to draw relevant policy implications for innovation diffusion.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.667-669
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• 2023

데이터의 균형은 객체 인식 분야에서 영향을 미치는 요인 중 하나이다. 본 논문에서는 폐기물 데이터 균형을 위해 Chat-GPT와 Diffusion model 기반 데이터 생성 모델을 제안한다. Chat-GPT를 사용하여 폐기물의 속성에 해당하는 단어를 생성하도록 질문하고, 생성된 단어는 인코더를 통해 벡터화시킨다. 이 중 폐기물과 관련 없는 단어를 삭제 후, 남은 단어들을 결합하는 전처리 과정을 거친다. 결합한 벡터는 디코더를 통해 텍스트 데이터로 변환 후, Stable Diffusion model에 입력되어 텍스트와 상응하는 폐기물 데이터를 생성한다. 이 데이터는 AI Hub의 공공 데이터를 활용하며, 객체 인식 모델인 YOLOv5로 학습해 F1-score와 mAP로 평가한다.

• Journal of Radiation Protection and Research
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• v.23 no.1
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• pp.1-6
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• 1998

A diffusion model of radioactive liquid effluents is developed and applied for YGN NPP's site, based on the Gaussian plume type model. Due to the complexity of oceanic diffusion characteristics of YGN site, a simple and reliable statistical model based on Reg. Guide 1.113 is developed. Also, a computer code package to calculate dilution factors as a function of plant operation conditions and pathway of radioactive materials. A liquid effluents diffusion model is developed by dividing the diffusion range into two categories, i. e, a near field mixing region and a far field mixing region. In the near field, the initial mixing is affected by a buoyance force, a high initial turbulence and momentum which is characterized by a plant operation condition and environmental conditions. The far field mixing is similar to gaseous effluents diffusion. So, beyond the near field region, wellknown Gaussian plume model was adopted. A different area averages of Gaussian plume equation was taken for each radioactive exposure pathway. As a result, we can get different dilution factors for different pathways. Results shows that present dilution factors used for YGN ODCM is too much overestimated compared with dilution factors calculated with the developed model.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.161-163
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• 1997

In this paper, a two-dimensional electron beam dose calculational algorithm implented for use in a two-dimensional radiation therapy planning system is described. The 2-D electron beam calculations have been in use clinically for a few decades. Our algorithm uses Age-diffusion model based int the Boltzman Transport Equation. Our implementation provides convenient user interface associated with electron beam therapy planning and displays radiation dose distribution according to different electron energy on patient images.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.127-138
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• 2003

Although the research on electronic commerce is plentiful, there is little empirical research related to Web-Based Shopping Systems (WBSS). This is especially so in global electronic commerce circumstances. WBSS are the fastest growing segment of digital economies and are perceived as driving forces of electronic commerce in terms of global markets and digital business. Using WBSS, organizations have a new chance of their business evolving successfully as global marketers. This paper develops a unified model to assess the diffusion of WBSS. Factors that impact WBSS diffusion are identified and analyzed as the basis for empirical testing. A set of propositions is developed that allows operationalization of the model. The ultimate goal is to provide the new research insights for the academic circles and the practical guidelines for organizations wishing to undertake WBSS.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.3
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• pp.46-56
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• 1998

The objective of this study was to investigate the relationship between water vapor diffusion properties and the pore structure of paper. Gas-phase molecular diffusivity of water vapor through pores was determined based on the kinetic theory of gas. A mathematical model was derived to characterize the dimensional changes of the pore caused by the fiber-swelling mechanism. A modified-Fickean diffusion model was designed to simulate the water-vapor diffusion phenomena in porous paper web. Structural characterisocs of paper pores including the tortuosity and the shape factor was studied on a theoretical basis of Knudsen flow diffusion. Results are summarized as follows: 1. The theoretical water vapor diffusivity in gas-phase was 0.092$cm^2$ /min, 2. Porosity was inversely proportional to the degree of wet-swelling of paper, 3. Solid-phase water-diffusivity of fiber was 1.2 $ \times 10^{-5}cm^2/min$, 4. Modified diffusion model was fairly consistent to the experimental data (from part I), and 5. The Fickean pore tortuosity, ranging from 1,000 to 2,500, was in inverse proportion to the porosity of paper, and the Knudsen shape factor and length-angle factor for micro-pores in paper were 0.5~3.5 and about 340, respectively.

• Korea Trade Review
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• v.45 no.1
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• pp.279-300
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• 2020

The cosmetic medical information mobile platform is evolving into a new channel for searching and obtaining relevant information before using cosmetic medical service. In addition, the medical institutions can facilitate the medical contracts, and take advantage of systemic customer management through the cosmetic medical information mobile platform. Therefore, the paradigm of the cosmetic medical mobile service industry is facing a flow of change through the use diffusion of cosmetic medical information mobile platform. In this study, in order to explore the factors affecting the use diffusion of the cosmetic medical information mobile platform, this study used the research model of the influence of the characteristics of the cosmetic medical information mobile platform on perceived convenience and usefulness, and use diffusion by applying TAM(Technology Acceptance Model). As a result, immediateness, interactivity, and customization in the characteristics of cosmetic medical information mobile platform had positive effects on the perceived convenience. Also, interactivity, customization, and economics had positive impacts on perceived usefulness. In addition, perceived convenience and usefulness had positive effects on the use diffusion. Through this study, the factors influencing the use diffusion of cosmetic medical information mobile platform were actually explored, and the service value of the cosmetic medical information mobile platform were categorized. Future research is expected to contribute to the continuous improvement of quality and expansion of the cosmetic medical service market based on various research.