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        검색결과 6

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study aims to develop a congestion mitigation strategy at lane drop bottleneck with low Connected and Automated Vehicle (CAV) penetration. METHODS : The proposed strategy is designed to assign a role of a moving bottleneck to CAVs to reduce low-speed lane changes at bottleneck locations, which are the main cause of bottleneck capacity drop. Through this, it aims to induce proactive upstream lane changes for Human-Driven Vehicles (HDVs,). Therefore, this study includes the control algorithm for CAVs, and the evaluation of the strategy assumes penetration rates of 5% and 10% in a Microsimulation VISSIM environment. The assessment is conducted by comparing the capacity drop and total travel time. Additionally, a sensitivity test for the parameter of the CAV control algorithm, reduced speed, is performed to find the optimal parameter. RESULTS : In this study, three scenarios, a) Base, b) CAV with no control, and c) CAV with control, are designed to evaluate the effects of the CAV control strategy. Analysis of segment density and lane change distribution reveals that the control strategy effectively prevented vehicle congestion due to the bottleneck effect. Additionally, the analysis of capacity changes before and after the bottleneck and total travel time shows the effectiveness of the control strategy. The sensitivity test on CAV control speed emphasized the importance of selecting an appropriate speed for maintaining efficient traffic flow. Lastly, as the CAV penetration rate increased, the control strategy exhibited greater effectiveness in mitigating capacity drop. CONCLUSIONS : The proposed strategy is intended for use at low CAV penetration rates and is expected to provide assistance in mitigating congestion at bottlenecks during the early stages of CAV commercialization. Furthermore, since the role of CAV in the strategy can be performed by CVs or even HDVs, it can be applied not only immediately but also in the near future.
        4,200원
        2.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한우와 함께 우리의 고유유전자원임에도 불구하고 한우에 비해 산업적 활용이 미흡한 칡소집단의 유전적 다양성과 특성을 파악하고자 실시하였다. 또한 멸종위기까지 처했던 칡소가 복원사업을 통해 일정 수준의 축군 확보에 성공하였지만 이 과정에서 유전적 다양성의 증감에 따른 유전적 병목현상 등의 현황을 파악하기 위해 11개의 MS 마커 유전자형을 이용해 분석을 수행했다. 관측(HObs) 및 기대 이형접합율(HExp)의 평균은 0.753, 0.765였으며, 다형정보지수(PIC)값은 0.732로 유전적 다양성은 비교적 높게 유지되고 있었다. 하디-바인베르크 평형(HWE) 검정결과 11개 좌위 중 5개 좌위는 유전적 평형 상태에서 유의적으로(p<0.05) 이탈해 있음을 확인했다. 칡소집단의 병목현상 여부를 검정하고자 11개 좌위의 대립유전자형을 3가지 변이 모델 IAM (Infinite Allele Model), SMM (Stepwise Mutation Model) 및 TPM (Two-Phase Mutation Model) 방법으로 추정했다. 본 연구에서 세 가지 검정 모두 칡소집단이 변이부동평형(Mutation Drift Equilibrium)에서 유의적으로 높게 이탈해 있음을 보였으며 이는 최근 유전적 병목현상이 발생했음을 시사한다. 희소 대립유전자 발생비율 검정결과 칡소 집단은 유전적 병목현상이 발생했음을 시사하는 모드변화(mode shifted) 분포를 보였다. 본 연구는 칡소를 대상으로 유전적 병목현상 여부를 분석한 최초의 보고이며 제시된 자료들은 새로운 육종소재로서 칡소의 활용과 이를 기반으로 한우산업의 다양한 육종 및 브랜드화 전략을 수립하는데 기초자료로 유용하게 활용 될 것으로 기대된다.
        4,000원
        3.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper seeks to present a multi-control method that can contribute to effective control of the production line with multiple bottleneck processes. The multi-control method is the production system that complements shortcomings of CONWIP and DBR, and it is designed to determine the raw material input according to the WIP level of two bottleneck processes and WIP level of total process. The effectiveness of the production system developed by applying the multi-control method was verified by the following three procedures. Raw material input conditions of the multi-control method are as follows. First, raw materials are go into the production line when the number of the total process WIP is lower than established number of WIP in total process and first process is idle. Second, raw materials are introduced when the number of WIP of two bottleneck processes is lower than the established number of WIP of each bottleneck process. Third, raw materials are introduced when the first process and in front of bottleneck process are idle even if the number of WIP in the total process is less than established number of WIP of the total process. The production line with two bottleneck processes was selected as the condition for production environment, and the production process modeling of CONWIP, DBR and multi-control production method was defined according to the production condition. And the optimum limited WIP level suitable for each system was obtained by applying a genetic algorithm to determine the total limited number of WIP of CONWIP, the limited number of WIP of DBR bottleneck process, the number of WIP in the total process of multi-control method and the limited number of WIP of bottleneck process. The limited number of WIP of CONWIP, DBR and multi-control method obtained by the genetic algorithm were applied to ARENA modeling, which is simulation software, and a simulation was conducted to derive result values on the basis of three criteria such as production volume, lead time and number of goods in-progress.
        4,000원
        4.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Manufacturing companies' cost competitiveness with respect to equipment management can be achieved by satisfying additional market demands by their own capacity without purchasing additional equipments. In essence, it can be accomplished by making continu
        4,600원
        5.
        2010.10 구독 인증기관·개인회원 무료
        The black soldier fly (Hermetia illucens) (Diptera: Stratiomyidae) is an invasive species that is thought to be endemic in Korea. The insect has been paid much attention thanks to its ability to decompose organic wastes. We collected the insect nation-wide in 2006 and 2010 to investigate its genetic structure based on the mitochondrial cytochrome oxidase 1 (mt CO1) haplotype. The results show that during the time period the insect seems to lose some rare haplotypes. We conclude that the insect may have experienced genetic bottleneck while its settlement in Korea. In our presentation, we show its updated haplotype network and genetic differentiation and propose potential explanations.
        6.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper studies procedures for bottleneck detection in closed queueing networks(CQN's) with multiple job classes. Bottlenecks refer to servers operating at 100% utilization. For CQN's, this can occur as the population sizes approach infinity. Bottlenec
        4,000원