• 조명전기설비학회논문지
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• 제28권1호
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• pp.79-87
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• 2014

With the increase of demand for electricity power, new construction and expansion of transmission lines for transport have been required. However, it has been difficult to be realized by such opposition from environmental groups and residents. Therefore, the development of techniques for effective use of existing transmission lines is more needed. In this paper, the major variables to affect the allowable transmission capacity in an overhead transmission lines were selected and the dynamic line rating (DLR) method using artificial neural networks reflecting unique environment-heat properties was proposed. To prove the proposed method, the analyzed results using the artificial neural network were compared with the ones obtained from the existing method. The analyzed results using the proposed method showed an error of 0.9% within ${\pm}$, which was to be practicable.

• International Journal of Internet, Broadcasting and Communication
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• 제13권4호
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• pp.55-65
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• 2021

The purpose of this paper is to present the Over-The-Top (OTT) platforms' strategies for two-sided markets. For this, we examine six strategic factors influencing OTT's success in Korea. The analysis reveals, among six OTTs, Netflix utilizes five strategic factors except the same-side network effects. OTTs from pay TV operators and channel providers tend to block the cross-side network effects on the opponent OTTs, because they think their giveaway to content providers is in vein, if the invested content by them would be consumed on opponent rival platforms. Interesting is that after experiencing a negative association between the market entry of Netflix and the subscription revenue growth rate of pay TV services, pay TV operators utilize the same-side network effects by offering hybrid services in partnership with global OTTs like Netflix, Disney+ which are considered as a complementary OTT. In conclusion, it is suggested to target a new connected TV based OTT service offering with collaboration with Korean TV device manufacturers for Korean OTTs' global strategy, because Netflix-like global market expansion is not easy for them to cover their content cost.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권10호
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• pp.3299-3312
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• 2022

Recently, South Korea preferentially allocated frequencies to build 5G networks as a core competitiveness of the 4th Industrial Revolution. Although the government recognize the importance of 5G construction and preoccupation, network operators have limited to some services, testing the possibility of practical use of 5G. They hesitated to actively build and to carry out the service of a complete 5G network. While 5G is being developed and standardized like this, no one is sure of this step exactly what 5G will be. Thus, following research questions are asked by various stakeholders of 5G market: What is an ideal service providing method for the practical use of 5th generation mobile network? And what are the critical elements to be considered when selecting the service providing method? Therefore, the study aims to investigate 5G service providing issues and elements to be considered and to provide most appropriate service providing method for the practical use of 5G. The results identify that 'Specialized Service' is most appropriate method at the aspects of benefit and opportunity as well as the aspect of risk. In addition, the outcomes imply that the experts replying to the survey not only expect the expansion of emerging market, but also concern the social risk and cost. Since the study dealt with economic, social and business issues in providing 5G service, it might contribute not only to practical research, but also to academic research regarding 5G service method.

• 산업융합연구
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• 제20권4호
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• pp.23-30
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• 2022

최근 인공지능(AI)과 딥러닝 발전으로 대화형 인공지능 챗봇의 중요성이 부각되고 있으며 다양한 분야에서 연구가 진행되고 있다. 챗봇을 만들기 위해서 직접 개발해 사용하기도 하지만 개발의 용이성을 위해 오픈소스 플랫폼이나 상업용 플랫폼을 활용하여 개발한다. 이러한 챗봇 플랫폼은 주로 RNN (Recurrent Neural Network)과 응용 알고리즘을 사용하며, 빠른 학습속도와 모니터링 및 검증의 용이성 그리고 좋은 추론 성능의 장점을 가지고 있다. 본 논문에서는 RNN과 응용 알고리즘의 추론 성능 향상방법을 연구하였다. 제안 방법은 RNN과 응용 알고리즘 적용 시 각 문장에 대한 핵심단어의 단어그룹에 대해 확장학습을 통해 데이터에 내재된 의미를 넓히는 기법을 사용하였다. 본 연구의 결과는 순환 구조를 갖는 RNN, GRU (Gated Recurrent Unit), LSTM (Long-short Term Memory) 세 알고리즘에서 최소 0.37%에서 최대 1.25% 추론 성능향상을 달성하였다. 본 연구를 통해 얻은 연구결과는 관련 산업에서 인공지능 챗봇 도입을 가속하고 다양한 RNN 응용 알고리즘을 활용하도록 하는데 기여할 수 있다. 향후 연구에서는 다양한 활성 함수들이 인공신경망 알고리즘의 성능 향상에 미치는 영향에 관한 연구가 필요할 것이다.

• 한국세라믹학회지
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• 제49권4호
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• pp.301-307
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• 2012

SiAlON glasses are silicates or alumino-silicates, containing Mg, Ca, Y or rare earth (RE) ions as modifiers, in which nitrogen atoms substitute for oxygen atoms in the glass network. These glasses are found as intergranular films and at triple point junctions in silicon nitride ceramics and these grain boundary phases affect their fracture behaviour. This paper provides an overview of the preparation of M-SiAlON glasses and outlines the effects of composition on properties. As nitrogen substitutes for oxygen in SiAlON glasses, increases are observed in glass transition temperatures, viscosities, elastic moduli and microhardness. These property changes are compared with known effects of grain boundary glass chemistry in silicon nitride ceramics. Oxide sintering additives provide conditions for liquid phase sintering, reacting with surface silica on the $Si_3N_4$ particles and some of the nitride to form SiAlON liquid phases which on cooling remain as intergranular glasses. Thermal expansion mismatch between the grain boundary glass and the silicon nitride causes residual stresses in the material which can be determined from bulk SiAlON glass properties. The tensile residual stresses in the glass phase increase with increasing Y:Al ratio and this correlates with increasing fracture toughness as a result of easier debonding at the glass/${\beta}-Si_3N_4$ interface.

• 한국정보통신학회논문지
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• 제18권5호
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• pp.1116-1121
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• 2014

메쉬 구조는 대표적인 상호연결망 중 하나로, VLSI 회로 설계 같은 분야에서 많이 이용되고 있다. 이러한 메쉬 구조에서 지름과 고장허용도를 개선한 연결망으로 토러스와 하이퍼-토러스 연결망이 있다. 본 논문에서는 토러스 구조 T(4k,2l)와 하이퍼-토러스 네트워크 QT(m,n) 사이의 임베딩을 분석한다. 토러스 T(4k,2l)는 QT(m,n)에 연장율 5, 밀집율 4, 확장율 1에 임베딩 가능하고, QT(m,n)은 T(4k,2l)에 연장율 3, 밀집율 3, 확장율 1에 임베딩 가능함을 보인다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2179-2183
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• 2009

As urbanization is progressed, the network for distributing water in a basin become complex due to the spatial expansion and parameter uncertainties of water supply systems. When a long range water supply plan is determined, the total construction and operation cost has to be evaluated with the system components and parameter uncertainties as many as possible. In this paper, the robust optimization approach of Bertsimas and Sim is applied in a hypothetical system to find a solution which remains feasible under the possible parameter uncertainties having the correlation effect between the uncertain coefficients. The system components to supply, treatment, and transport water are included in the developed water supply system and construction and expansion of the system is allowed for a long-range period. In this approach, the tradeoff between system robustness and total cost of the system is evaluated in terms of the degree of conservatism which can be converted to the probability of constraint violation. As a result, the degree of conservatism increases, the total cost is increased due to the installation of large capacity of treatment and transportation systems. The applied robust optimization technique can be used to determine a long-range water supply plan with the consideration of system failure.

• 한국정보시스템학회지:정보시스템연구
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• 제27권3호
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• pp.63-80
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• 2018

Purpose The purpose of this study is to build a machine learning-based customer classification model to promote customer expansion effect of the free sample promotion. Specifically, the proposed model classifies potential target customers who are expected to purchase the products included in the free sample promotion after receiving the free samples. Design/methodology/approach This study proposes to build a customer classification model for determining customers suitable for providing free samples by using various machine learning techniques such as logistic regression, multiple discriminant analysis, case-based reasoning, decision tree, artificial neural network, and support vector machine. To validate the usefulness of the proposed model, we apply it to a real-world free sample-based target marketing case of a Korean major cosmetic retail company. Findings Experimental results show that a machine learning-based customer classification model presents satisfactory accuracy ranging from 70% to 75%. In particular, support vector machine is found to be the most effective machine learning technique for free sample-based target marketing model. Our study sheds a light on customer relationship management strategies using free sample promotions.

• Smart Structures and Systems
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• 제14권1호
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• pp.55-70
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• 2014

The paper presents a multi-objective optimization strategy for a multi-type sensor placement for Structural Health Monitoring (SHM) of long span bridges. The problem is formulated for simultaneous placement of strain sensors and accelerometers (heterogeneous network) based on application demands for SHM system. Modal Identification (MI) and Accurate Mode Shape Expansion (AMSE) were chosen as the application demands for SHM. The optimization problem is solved through the use of integer Genetic Algorithm (GA) to maximize a common metric to ensure adequate MI and AMSE. The performance of the joint optimization problem solved by GA is compared with other established methods for homogenous sensor placement. The results indicate that the use of a multi-type sensor system can improve the quality of SHM. It has also been demonstrated that use of GA improves the overall quality of the sensor placement compared to other methods for optimization of sensor placement.

• 한국컴퓨터정보학회논문지
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• 제11권2호
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• pp.223-230
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• 2006

휴대 인터넷은 high-speed 무선 인터넷 서비스를 제공하는 새로운 서비스이다. high-speed 무선 인터넷 서비스는 터미널 이동성을 제공한다 휴대인터넷은 2006년에 상업화될 것으로 예상된다. 네트워크 확장과 터미널 이동성은 효율적 소개와 분산 이동 인터넷 서비스를 위해서 보장되어야 한다. 따라서 이 논문에서는 휴대 인터넷의 이동성과 호가장성을 보장하기 위해서 이동 IPv6 기술과 휴대 인터넷의 이동성을 적용한 메커니즘을 제안한다. 제안된 메커니즘은 보안성을 향상시키기 위해서 인터 도메인에서 다이어미터 프로토콜을 적용한다. 또한, 제안된 메커니즘은 데이터 보안성을 제공하기 위해 최소의 시그널 수로 데이터를 안전하게 전송한다.