• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2159-2166
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• 1996

The stochastic properties of variation in fatigue crack growth are important in reliability and stability of structures. In this study,the stochastic model for the variation of fatigue crack growth rate was proposed in consideration of nonhomogeneity of materials. For this model, experiments were ocnducted on 7075-T6 aluminum alloy under the constant stress intensity factor range. The variation of fatigue crack growth rate was expressed by random variables Z and r based on the variation of material coefficients C and m in the paris-Erodogan's equation. The distribution of fatigue life with respect to the stress intensity factor range was evaluated by the stochastic Markov chain model based on the Paris-Erdogan's equation. The merit of proposed model is that only a small number of test are required to determine this this function, and fatigue crack growth life is easily predicted at the given stress intensity factor range.

• Journal of Venture Innovation
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• v.1 no.1
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• pp.1-14
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• 2018

The 4th Industrial Revolution is making a big change for our company like the tsunami. The CPS system, which is represented by the digital age, is based on the data accumulated in the physical domain and is making business that was not imagined in the past through digital technology. As a result, the business model of the 4th Industrial Revolution era is different from the previous one. In this study, we analyze the trends and the issues of business innovation theory research. Then, the business innovation model of the digital age was compared with the previous period. Based on this, we have searched for a business model suitable for the 4th Industrial Revolution era. The existing business models have many difficulties to explain the model of the digital era. Even though more empirical research should be supported, Michael Porter's diamond model is most suitable for four cases of business models by applying them. Type A sharing outcome with customer is a model that pay differently according to the basis of customer performance. Type B Value Chain Digitalization model provides products and services to customers with faster and lower cost by digitalizing products, services and SCM. Type C Digital Platform is the model that brings the biggest ripple effect. It is a model that can secure profitability by creating new market by creating the sharing economy based on digital platform. Finally, Type D Sharing Resources is a model for building a competitive advantage model by collaborating with partners in related industries. This is the most effective way to complement each other's core competencies and their core competencies. Even though numerous Unicorn companies have differentiated digital competitiveness with many digital technologies in their respective industries in the 4th Industrial Revolution era, there is a limit to the number of pieces to be listed. In future research, it is necessary to identify the business model of the digital age through more specific empirical analysis. In addition, since digital business models may be different in each industry, it is also necessary to conduct comparative analysis between industries

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.501-519
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• 2017

With the revolution of IT technology, cyber threats and crimes are also increasing. In the recent years, many large-scale APT attack executed domestically and internationally. Specially, many of the APT incidents were not recognized by internal organizations, were noticed by external entities. With fourth industrial revolution(4IR), advancement of IT technology produce large scale of sensitive data more than ever before; thus, organizations invest a mount of budget for various methods such as encrypting data, access control and even SIEM for analyzing any little sign of risks. However, enhanced intelligent APT it's getting hard to aware or detect. These APT threats are too much burden for SMB, Enterprise and Government Agencies to respond effectively and efficiently. This paper will research what's the limitation and weakness of current defense countermeasure base on Cyber Kill Chain process and will suggest effective and efficient APT defense operation model with considering of organization structure and human resources for operation.

• The Journal of the Convergence on Culture Technology
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• v.3 no.4
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• pp.137-144
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• 2017

The purpose of this study is to examine the effectiveness of Customer Relationship Management (CRM) factors in the Supply Chain Management (SCM) context focusing on ashion apparel company. Especially, this study reveals whether a long term relationship is beneficial for all businesses regardless of negotiation power leverage. To this end, the mixed research methods that combined qualitative and quantitative approaches were conducted. The findings of this study are as follows: First, the research model which is CRMs for interactive relationship building were developed. Second, cause-and-effect relationships in the proposed model were partially supported depending on CRMs. The most effective CRMs offered are a guarantee of sales and a special discount. Customized products and quality, convenience, competitive pricing, and development of a product/system/service were effective to ultimately increase a switching cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2452-2457
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• 2012

When a quality inspection process rejects a product unit, consecutive repeated inspections are sometimes conducted for the rejected unit to reduce a false reject possibility. This paper analyzes a special inspection process that allows up to two times of consecutive testing for each product to decrease type I inspection errors. This study uses a Markov chain to model the steps of the inspection process and a product unit's quality states during inspection. Historical inspection results from a company are used as the data for the Markov chain model. Using the Markov chain model and data, this study analyzes the effect of this special inspection rule on the proportion of the final quality levels and scrap rate. The results demonstrate that this inspection process of possible double testing could help reduce unnecessary rejects and consequently decrease material and production costs.

• Membrane Journal
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• v.29 no.1
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• pp.37-43
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• 2019

In this study, we investigated how the force-field, which is the most important factor to define atomic motion in molecular dynamics (MD), affects the motion of the polymer and gas molecules. The repeat units and the polymer structure were well simulated in all five force-fields, and the distribution of the polymer linear chain in the final polymer 3D model did not show any significant difference. However, the movement of actual gas molecules showed a very different tendency, which was also observed in COMPASS and pcff using the same functional form. Therefore, even if the same structure is used, it can be seen that the motion of the gas molecule moves under the influence of the force-field continuously over time, so that the effect is much larger than that of macromolecules such as a polymer linear chain. Accordingly, in case of using different force-fields, it is necessary to be very careful in comparison of those results.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.4
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• pp.99-107
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• 2003

In this paper we propose an international cross certification model using cross certificate. We propose a new model by analyzing and solving current problems of the National PKI. We recommend a certificate profile, design a directory schema, and propose a method to access PSE(personal security environment) using PKCS＃11, which gives the expansibility and convenience. Finally, we propose a certificate path verification method using RFC 3280 and show how to get the certificate chain by using the trust anchor. This model is recommended to the detailed level of specification for the interoperability of each country's PKI.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.196-196
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• 1994

DDS에 활용될 수 있는 고분자 소재를 개발할 목적으로 물성 및 응용성이 우수한 고분자 겔에 관한 연구를 수행하였다. Ethylene oxide,propylene oxide 각각의 copolymer인 poloxamer등의 prepolymer들을 triisocyanate로 가교시키고 diisocyanate 로 chain이 연장된 "soft hydrogel"을 제조하였다. 모델 약물을 선정하여 crosslinker와 extender의 조절에 따른 hydrogel의 약물 방출 조절능을 조사하였으며 그 기전을 규명하고자 하였다. 가교부위에 urethane bond를 함유한 soft hydtogel은 건조상태에서도 고무와 같은 전연성을 보여 일반적인 hydrogel과 대비되는 특성을 보였으며 이에 따른 다양한 활용성이 기대되었다. Extender및 crosslinker의 비율에 따라서 이 rubber elasticity가 조절되었다. 가교도가 감소할수록 팽윤도가 상승하였고 이에 따른 약물방출도 증가함을 확인하였다. 또한 Prepolymer의 분자량 및 친수/소수성등의 물성에 따라 약물방출을 조절할 수 있었다. 제조된 hydrogel에 조절방출시 필요한 기능을 부가시키고자 poly(carylic acid)류와 IPN 공중합체를 합성하여 물성을 조사하였고 비이온성/양이온성/음이온성 모델약물을 선정하여 pH에 따른 가변적 팽윤도와 이온성 상호작용등에 근거한 약물 조절방출기전을 조사하였다.기전을 조사하였다.

• Electronics and Telecommunications Trends
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• v.32 no.2
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• pp.10-18
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• 2017

4차 산업혁명 시대 인터넷이 소비자 중심에서 산업계 중심으로 진화함에 따라 주요국은 기존 산업의 경쟁력 강화를 위한 정책방안을 마련하여 추진하고 있다. 글로벌 기업 CEO들은 장기적인 불확실성을 최소화하기 위해 산업인터넷 융합의 가치사슬, 비즈니스 모델, 시장전망, 그리고 생태계 조성에 관심이 높다. 본 연구는 산업인터넷(Industrial IoT: IIoT) 분야 국가경쟁력 제고, 효율적 시장 창출 등을 지향하는 방향으로 국가 차원의 거버넌스, 출연(연) 융합 연구개발 및 표준화, 테스트베드 전국화, 법제도 정비 등 정책 마련을 위한 산업인터넷 가치사슬(Value Chain), 비즈니스 모델, 시장조사 기관의 시장전망, 미국 중심의 생태계 조성 동향을 제시하고 있다.

• Electronics and Telecommunications Trends
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• v.26 no.2
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• pp.25-32
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• 2011

한국은 세계적으로 정부 주도의 IT 정책이 가장 성공한 나라로 평가되어 왔으나 최근 스마트폰 등 모바일 중심의 세상이 도래하면서 기존 정보통신사업 생태계가 크게 요동치고 있다. 더욱이 이러한 새로운 패러다임 및 BM이 미국발이어서 새로운 시장 창출형 정책선도 모델 발굴이 매우 시급하다. 그러나 과거와는 전혀 다른 새로운 환경, 즉 규제의 힘이 약해지고 새로운 Value Chain 및 산업조직 등 시장의 힘이 강해진 상황에서 이용자의 참여를 유도하고 궁극적으로 시장의 잠재적 수요를 창출할 수 있는 소통적 정책모델 정립이 매우 중요하다고 할 수 있다. 이러한 관점에서 통신산업은 수동적으로 관리해야 할 대상이 아니라 미래 국가경쟁력을 위해서 적극적으로 진흥, 육성해야 할 분야라는 인식전환이 그 어느 때보다 필요하다.