• 한국시스템다이내믹스연구
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• 제11권1호
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• pp.59-83
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• 2010

The Korean Government decided to reduce 30% of carbon emissions as of 2020, tightening regulations to reduce greenhouse gas in the international society. Therefore it will burden Korean logistics industry that overland trucking freight covers 70~80% of all, to lower emissions. As known, rail and coast(feeder) transport systems can be substituted for road transport but there are many problems to solve in Korean multimodal (intermodal) transport system such as time, cost, etc. Because of this, multimodal transport system should be improved systematically. For the reason, it aims to study a conceptual model with Thinking Process of TOC(theory of constraints) and System Dynamics to help improve the existing multimodal transport system for green logistics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.427-429
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• 2003

The reliability performance of distribution networks will be enhanced with the installation of application programs including feeder reconfiguration program for loss minimization and optimization of system capacity. Although the basic functions of remote monitoring and remote control provide no measurable cost benefit the suite of application programs developed and now being commissioned by KEPCO, the future will continue to offer this utility with substantial savings in system operational costs, improve system reliability and customer service.

• 지능정보연구
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• 제28권2호
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• pp.263-278
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• 2022

최근 IoT 기술의 발달로 외출 중에도 반려동물에 급여하도록 자동 사료급식기가 유통되고 있다. 그러나 자동급식에서 중요한 중량을 측정하는 저울 방식은 쉽게 고장이 나고, 3D카메라 방식은 비용이 든다는 단점이 있으며, 2D카메라 방식은 중량 측정의 정확도가 떨어진다. 특히 사료가 복합된 경우 중량 측정 문제는 더욱 어려워질 수 있다. 따라서 본 연구의 목적은 2D카메라를 사용하면서도 중량을 정확하게 추정할 수 있는 딥러닝 접근법을 제안하는 것이다. 이를 위해 다양한 합성곱 신경망을 이용하였으며, 그중 ResNet101 기반 모델이 3.06 gram의 평균 절대 오차와 3.40%의 평균 절대비 오차를 기록하며 가장 우수한 성능을 보였다. 본 연구의 결과로 사료와 같이 규격화된 물체의 중량을 확보가 용이한 2D 이미지를 통해서만 예측할 필요가 있을 경우 유용한 정보로 활용될 수 있다.

• 대한교통학회지
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• 제26권5호
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• pp.227-235
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• 2008

본 연구에서는 간선-지선 노선체계인 가지형과 지선형 노선체계의 이용자 비용과 운영자 비용을 비교하여 각 노선체계의 효율성을 분석하였다. 기본적으로 지선형 노선체계의 간선구간 시스템이 지선 시스템과 동일할 경우에는 이용자 측면에서 가지형 노선체계가 보다 효율적이다. 간선구간의 시스템이 지선구간의 시스템보다 상위 위계의 시스템일 경우에는 지선형 노선체계의 간선운행 시스템을 통한 통행비용 절감이 그에 따라 추가적으로 발생하는 환승과 대기비용보다 클 경우에 지선형 노선체계가 기지형 노선체계보다 효율적이다. 이는 격자형 대중교통 노선망에 대해 위계구조 노선망의 효율성을 분석한 박준식 외(2007c)의 연구결과와 일치하는 결과이다. 각 기종점간 통행수요가 적을 경우에는 지선형 노선체계에서 각 지점의 통행수요에 맞추어 운행간격을 증가시켜 차량의 승객 탑승률 또는 운행효율을 높이는 방안을 모색할 수 있다. 이 경우 차량 운행비용계수 노선길이, 그리고 종점 수가 증가할수록 지선형 노선체계가 효율적일 상황이 증가하고, 환승비용과 통행자의 대기시간 비용환산계수가 증가할수록 지선형 노선체계가 효율적일 상황이 감소한다. 간선구간의 중간에 도시 중심지가 위치하여 승하차 통행수요가 발생하는 경우, 간선의 중간에 위치하는 도시 중심지로의 통행량이 많을수록 지선형 노선체계가 가지형 노선체계보다 효율적일 상황이 증가한다. 따라서 승하차 수요가 집중되는 도시 중심부와 수요가 분산되어 있는 외곽부의 노선체계를 이원화시킬 경우 하나의 노선체계로 운영하는 경우보다 효율적이라 결론내릴 수 있다. 원활한 환승체계를 갖추어 환승비용을 감소시킬 경우 더욱 효과적이라 하겠다.

• 한국레이저가공학회지
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• 제15권4호
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• pp.12-15
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• 2012

On behalf of the existing semiconductor process, the electronic devices to low-cost mass production to mass print the way, the research for development of roll-to-roll printing process is actively underway. This study was performed in about the research on the manufacturing technology of the printing roll used in the printing process of electronic devices. The indirect laser imprinting technology was used to create printable roll, and after coating copper on the surface of steel and thereon after coating polymer, after removing the polymer on the surface of roll, the printable roll was made. The laser system and roll feeder system were constructed and control program was developed. We has found the optimal conditions to perform laser patterning experiments using a system developed and We can make the minimum line width of 18 ${\mu}m$.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.580-590
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• 2018

Active distribution system (ADS) considering distributed generation (DG) and electric vehicle (EV) is an effective way to cut carbon emission and improve system benefits. ADS is an evolving, complex and uncertain system, thus comprehensive model and effective optimization algorithms are needed. Battery swapping station (BSS) for EV service is an essential type of flexible load (FL). This paper establishes ADS planning model considering BSS firstly for the minimization of total cost including feeder investment, operation and maintenance, net loss and carbon tax. Meanwhile, immune binary firefly algorithm (IBFA) is proposed to optimize ADS planning. Firefly algorithm (FA) is a novel intelligent algorithm with simple structure and good convergence. By involving biological immune system into FA, IBFA adjusts antibody population scale to increase diversity and global search capability. To validate proposed algorithm, IBFA is compared with particle swarm optimization (PSO) algorithm on IEEE 39-bus system. The results prove that IBFA performs better than PSO in global search and convergence in ADS planning.

• 전기학회논문지
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• 제64권10호
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• pp.1418-1425
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• 2015

In this paper, an filtering method of FI(Fault Indication) information generated by FRTU(Feeder Remote Terminal Unit)s is proposed for the present DAS(Distribution Automation System). In order to find fault area, correct FI information should be generated. But when a single line-to-ground fault occurs, FI information is generated in downside of the fault in some circumstance because existing FI algorithm considers only magnitude. These wrong FI information can be removed by changing existing algorithm. An improved algorithm considers both the direction of zero-sequence current and the phase of three-phase current&voltage. But many FRTUs are distributed in DAS and Changing the algorithm all of FRTU will spend a lot of time and cost. On the other hand, an filtering algorithm proposed in this paper can substitute for it. The filtering algorithm also considers both the direction of zero-sequence current and the phase of three-phase current&voltage. In case study, the proposed method has been shown the reasonability in filtering the fault indication information.

• 한국항해항만학회지
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• 제45권2호
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• pp.75-86
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• 2021

This paper intends to evaluate the policies which are considered necessary to enhance the T/S competitiveness of Busan's port, and thereby present suggestions to the government which would best implement the results of this research. This research first raises the claim that the majority of the following four conditions: location of the port, port productivity/service level, status of network with overseas ports, and cost competitiveness, should be satisfied in order to maintain a competitive T/S port. Based on these four conditions, seven policies, which are individually pertinent to the four conditions, have been drawn up for proposal, and they are also analyzed in the survey, where all the eligible samples participate to ensure if they are effective in enhancing the T/S competitiveness of Busan. Proposed important policies are a) Terminal operator integration, b) port infrastructure expansion, c) global carriers owned terminal operation, d) enhancement of national carrier's competitiveness, e) feeder carriers' owned terminal operation in new port, f) institutional support for effective and convenient environments for handling T/S cargo, and g) volume incentive expansion. From the analysis by which all the relevant parties (Carriers, Terminal Operators, Port Authority) are answered, it was found that all the seven policies have relevance in strengthening the transshipment competitiveness of Busan's port. Whereas in the analysis that uses AHP methodology to compare the significance among the different policies, it was found that terminal operator integration has the highest priority in terms of increasing transshipment competitiveness.

• 한국동물생명공학회지
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• 제38권3호
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• pp.121-130
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• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• 한국항해항만학회지
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• 제32권1호
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• pp.65-72
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• 2008

본 연구의 목적은 동아시아 지역을 중심으로 글로벌 항만 물류네트워크를 구축하여 우리나라의 새로운 항만정책을 제안하는 것에 있다. 이러한 항만 물류네트워크의 구축을 위해 세계 50위 항만 중 21개의 항만을 중심으로, 컨테이너 화물량과 기항지를 분석하여 EU, 북미를 연결시 최소 물류비용인 동아시아 지역의 4개의 대표항만을 추출하였다. 그 결과 동아시아에서는 싱가포르, 홍콩, 상하이, 부산항이 추출되었다. 따라서, 우리나라는 싱가포르, 홍콩, 상하이항에 해외 터미널을 운영하고 부산항과 연계하는 글로벌 항만 물류네트워크를 구축하여 안정적인 화물을 확보해야 한다.