• 한국산학기술학회논문지
• /
• 제22권2호
• /
• pp.452-458
• /
• 2021

인터넷 환경과 컴퓨팅 환경이 활용되는 분야 증가로 개인정보의 활용가치와 중요성이 높아지고 있으며, 사용자 인증 기술 또한 변화하고 있다. 현재까지 금융권 위주로 사용되고 있는 공인인증서는 폐지 문제로 생체인증 기술로 교체되고 있다. 하지만 생체정보는 한번 유출되면 수정할 수 없다는 문제점을 내포하고 있다. 최근 블록체인 기술의 등장으로 사용자 인증 방식에 대한 연구가 활발하게 진행되고 있다. 본 논문에서는 공인인증서와 블록체인 기반 사용자 인증 방법 모두를 시스템 변경 없이 사용할 수 있도록 설계하였으며, 주민등록번호를 대체할 수 있는 새로운 분산 ID(DID) 발급 및 재발급, 검증, 위임 방법을 제안한다. 제안하는 시스템에서는 블록체인에 제한 없이 사용이 가능하다. 단 현재 사용되고 있는 분산 ID는 검증을 위해 상호연동지원센터에 응용프로그램 설치가 필요하다. 분산 ID는 별도의 회원가입 없이 인증할 수 있으므로 무분별한 정보 수집을 방지할 수 있다. 기존 시스템과 보안성, 편의성, 확정성을 비교하였으며, 다양한 공격방법과 휴대성, 대리 사용 등을 통해 우수함을 입증하였다.

• 한국융합학회논문지
• /
• 제12권8호
• /
• pp.207-214
• /
• 2021

기존의 연구에서 기업의 다각화 정도가 클수록 기업가치가 하락한다는 다각화 할인 현상이 발생한다는 일관된 결과를 제시하고 있다. 그런데도 기업들이 지속해서 다각화를 추진하는 요소로 대리인 이론으로 설명된다. 그리고 대리인 문제를 해소하기 위해서는 효율적인 지배구조를 형성하는 것이 중요하다. 하지만 기존의 연구들은 주로 경영지분율 등을 중심으로 이루어져 왔고 이사회를 구성하는 개인에 대한 고려가 부족하다. 본 연구에서는 이러한 문제점들을 해결하기 위하여 이사들의 겸임 정보를 통하여 이들의 겸임이 이사회의 모니터링 효과에 어떠한 영향을 이를 통해 다각화에 어떠한 영향을 끼치는지 연구하고자 한다. 이를 위하여 2011년부터 2016년까지 6년간 유가증권시장에 기업을 대상으로 연구를 진행하였다. 분석 결과, 경영자와 사내이사 겸임의 경우 양(+)의 영향을 미치기는 하였으나 유의성은 확인할 수 없었다. 사외이사 겸임의 경우 다각화에 유의한 양(+)의 결과를 확인하였다.

• 한국농공학회논문집
• /
• 제64권5호
• /
• pp.67-77
• /
• 2022

Recently, the trend in structural analysis and design is moving towards the development of reliable system. The reliability-based method defines various limit states related to usability and failure, thereby enabling multiple levels of design according to the importance of a structure. Meanwhile, an actual structure is composed of a set of several elements, and particularly, a frame type is composed of a system in which the members are connected each other. At this time, the actual connection between members is in a semi-rigid condition, not in complete rigid or hinged. This semi-rigid is found in several structures, especially in agricultural facilities designed with lightweight materials. In this study, a system reliability analysis technique for frame structure was established, and applied to an analysis of the semi-rigid connection. Various conditions of correlation were applied to reflect the connectivity between members, and through this, the limitations of existing structural analysis method and the behavioral characteristics of structure were analyzed. The failure probability of the frame member component and the overall structure system was significantly different in consideration of the semi-rigid connection. In addition, it was evaluated that the behavior of structure can be more accurately analyzed if the correlation according to the position of members in a system is further investigated.

• Geomechanics and Engineering
• /
• 제32권1호
• /
• pp.69-84
• /
• 2023

This paper proposes a novel frame element on Winkler-Pasternak foundation for analysis of a non-ductile reinforced concrete (RC) member resting on foundation. These structural members represent flexural-shear critical members, which are commonly found in existing buildings designed and constructed with the old seismic design standards (inadequately detailed transverse reinforcement). As a result, these structures always experience shear failure or flexure-shear failure under seismic loading. To predict the characteristics of these non-ductile structures, efficient numerical models are required. Therefore, the novel frame element on Winkler-Pasternak foundation with inclusion of the shear-flexure interaction effect is developed in this study. The proposed model is derived within the framework of a displacement-based formulation and fiber section model under Timoshenko beam theory. Uniaxial nonlinear material constitutive models are employed to represent the characteristics of non-ductile RC frame and the underlying foundation. The shear-flexure interaction effect is expressed within the shear constitutive model based on the UCSD shear-strength model as demonstrated in this paper. From several features of the presented model, the proposed model is simple but able to capture several salient characteristics of the non-ductile RC frame resting on foundation, such as failure behavior, soil-structure interaction, and shear-flexure interaction. This confirms through two numerical simulations.

• Journal of Korea Trade
• /
• 제26권7호
• /
• pp.109-126
• /
• 2022

Purpose - Based on the relevant panel data for China and 13 of the RCEP countries from 2008-2019, this paper conducts an in-depth study on the impact of trade facilitation levels on China's cross-border e-commerce exports using the expanded trade gravity model. Design/methodology - This study constructs a trade facilitation index (TFI) system, and uses the principal component analysis method to measure the trade facilitation levels of RCEP countries in 2008-2019. This result is then introduced into the extended gravity model to explore the effect of trade facilitation in RCEP countries on China's cross-border e-commerce export. Findings - It is found that the overall trade facilitation level has a significant effect on China's cross-border e-commerce exports. Among the primary indicators, with the exception of infrastructure, the other four indicators demonstrate a significant impact. The findings show that China should strengthen its cooperation with RCEP countries in trade facilitation and cross-border e-commerce to better achieve complementary regional economic development. Originality/value - This paper has three contributions: first, this paper builds a TFI system that includes five primary indicators based on the characteristics of cross-border e-commerce. Second, we explore the impact of trade facilitation levels of RCEP countries on China's cross-border e-commerce exports, which helps to fill the gap in existing studies of the impact of cross-border e-commerce exports. Third, this paper further analyzes the impact of five primary indicators on cross-border e-commerce exports; this thus provides more targeted measures to improve trade facilitation levels.

• 한국농촌건축학회논문집
• /
• 제24권2호
• /
• pp.13-20
• /
• 2022

In this study, a general low-rise building was selected to compare the new shear wall reinforcement method, which is a general method among the existing reinforcement methods, and the reinforcement method using sinusoidal corrugated web reinforcement. And it was confirmed that the following effects can be expected. Sinusoidal corrugated web members can be carried out in a short period of time as it does not require the removal of the masonry filling wall, the reinforcement of reinforcing bars, and the curing period of the concrete. It is effective in preventing damage that may occur when masonry filling wall is overturned in the out-of-plane direction, and the burden of the foundation is also reduced, and thus the construction period and cost required for reinforcement can greatly be reduced. By adjusting the number of sinusoidal corrugated web member, details of joints, and reinforcement positions, the flow of load can be induced to have an advantageous effect on the building. It can be considered as the most suitable reinforcement plan in terms of life safety. Unlike the shear wall that fills between the columns, the sinusoidal corrugated web members, which has a width of 1.5m, can install openings between two columns depending on the purpose of use, and can be expected to have a great effect in terms of usability due to its free installation location. As mentioned above, the seismic reinforcement using a sinusoidal corrugated web members, can expect great effect compared to conventional reinforcement methods in terms of usability, economic feasibility, and stability.

• Steel and Composite Structures
• /
• 제45권1호
• /
• pp.133-145
• /
• 2022

Steel fiber composite bar (SFCB) is a novel type of reinforcement, which has good ductility and durability performance. Due to the unique pseudo strain hardening tensile behavior of SFCB, different flexural behavior is expected of SFCB reinforced concrete (SFCB-RC) beams from traditional steel bar reinforced concrete (S-RC) beams and FRP bar reinforced concrete (F-RC) beams. To investigate the flexural behavior of SFCB-RC beam, four points bending tests were carried out and different flexural behaviors between S/F/SFCB-RC beams were discussed. An flexural analytical model of SFCB-RC beams is proposed and proved by the current and existing experimental results. Based on the proposed model, the influence of the fiber volume ratio R of the SFCB on the flexural behavior of SFCB-RC beams is discussed. The results show that the proposed model is effective for all S/F/SFCB-RC flexural members. Fiber volume ratio R is a key parameter affecting the flexural behavior of SFCB-RC. By controlling the fiber volume ratio of SFCB reinforcements, the flexural behavior of the SFCB-RC flexural members such as bearing capacity, bending stiffness, ductility and repairability of SFCB-RC structures can be designed.

• 한국산업융합학회 논문집
• /
• 제26권6_3호
• /
• pp.1279-1288
• /
• 2023

Recently, domestic leisure boats have been actively researching eco-friendly product development to enter the global market. Since the hulls of existing leisure boats are mainly made of fiber reinforced plastic (FRP) or aluminum, design techniques for securing structural safety by applying related materials have been mainly studied. In this study, an initial structural design safety assessment of a trimaran pontoon leisure boat with a modular hull structure and eco-friendly high-density polyethylene (HDPE) material was conducted, and sensitivity evaluation and optimization analysis for lightweight design were performed. The initial structural design safety assessment was carried out by creating a finite element analysis model and applying the loading conditions specified in the ship classification regulation to check whether the specified allowable stresses are satisfied. For the sensitivity evaluation, the influence of stress and weight of each hull structural member was evaluated using the orthogonal array design of experiments method, and an approximate model based on the response surface method was generated using the results of the design of experiments. The optimization analysis set the thickness of the hull structural members as the design variable and considered the optimal design formulation to minimize the weight while satisfying the allowable stress. The algorithm of the optimization analysis applied the Gradient-population Based Optimizer (GBO) to improve the accuracy of the optimal solution convergence while reducing the numerical cost. Through this study, the optimal design of a newly developed eco-friendly trimaran pontoon leisure boat with a weight reduction of 10% was presented.

• 한국터널지하공간학회 논문집
• /
• 제25권6호
• /
• pp.447-458
• /
• 2023

본 연구에서는 쉴드터널 세그먼트 라이닝의 하중과 부재저항의 확률적 특성뿐만 아니라 경계조건의 변동성을 고려한 비교모델을 선정하고 신뢰성해석을 수행하였으며, 파괴확률 산정 및 구조안전성 검토를 통해 한계상태설계의 적정성에 대해 분석을 수행하였다. 이러한 지반 정수의 확률특성치를 고려한 해석을 위해 지반스프링계수는 Muirwood식을 적용하여 정량적 값을 산정하여 Mean값으로 고려하였고, 변동계수는 기존 연구자료를 토대로 지반 경계조건 변화에 따른 검토대상 모델들을 선정하였다. 이러한 모델들에 대한 구조해석과 MCS기법을 적용한 신뢰성분석을 통해 파괴확률과 신뢰성지수를 산정하여 지반경계조건 변화에 따른 파괴확률의 변화를 검토하였다.

• 한국정보과학회논문지:시스템및이론
• /
• 제29권3호
• /
• pp.125-133
• /
• 2002

본 논문은 대규모 분산시스템에서 전체 순서화를 유지하는 방송통신 프로토콜을 제안한다. 기존의 토큰기반 방송통신 프로토콜과는 달리 제안된 프로토콜에서 토큰은 방송도메인을 구성하는 링을 묵시적으로 회전하지는 않는다. 대신에 토큰 전송을 위한 세 개의 메시지를 사용한다. 토큰은 방송메시지를 위한 순서번호 정보를 갖고 있으며, 오직 토큰을 소유한 노드만이 방송메시지를 전송할 수 있다. 방송메시지를 전송하려 하는 노드는 토큰을 소유한 토큰노드로 토큰요청메시지를 보내고, 토큰노드는 요청한 노드에게 토큰을 전송한다. 토큰을 요청한 노드가 토큰을 소유하게 되면 토큰의 순서정보를 이용하여 방송메시지를 전송한다. 이 메시지를 수신한 모든 노드는 토큰노드가 변경되었음을 인식하게 되고, 새로운 토큰노드로 토큰을 요청하게 된다. 그러나, 새로운 토큰 노드로부터 방송메시지를 수신하기 전에 과거의 토큰노드로 토큰요청메시지를 전송하는 노드가 존재할 수 있다. 이 문제를 해결하기 위해 제안된 프로토콜은 과거 토큰노드가 새로운 토큰노드에게 다음 토큰요청노드를 알리는 메시지를 사용한다. 시뮬레이션 결과를 통해 기존의 방송통신 프로토콜보다 제안된 프로토콜이 대규모 분산시스템에서 더욱 효율적이라는 것을 알 수 있다.