• 한국항만경제학회지
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• 제35권2호
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• pp.109-126
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• 2019

2018년 남북정상의 4.27 판문점 선언으로 한반도의 평화 및 협력 분위기가 조성되고, 그해 6월에는 국제철도협력기구(OSJD) 가입으로 한반도를 포함하여 중국, 러시아 등 유라시아와 연계하는 복합물류체계 기반이 마련되었다. 본 논문에서는 한반도와 유라시아를 효율적으로 연결하는 복합물류 네트워크 구축하는데 애로사항을 파악하기 위하여 현재 대륙철도를 이용하고 있는 실무전문가를 대상으로 설문조사를 실시했다. 설문항목은 국경통과 절차, 기술, 시설, 운영, 정부지원 측면 등 5가지로 나누어 애로정도와 해결 우선순위 점수를 조사했다. 그 결과 한국-유라시아간 국제 복합운송 문제점 중에서 우선 해결해야 할 과제로는 환적 시설을 개선하고, 통과국마다 검사하는 것을 폐지하고 통관서류를 간소화해야 하며, 운임변동을 최소화하는 방안 마련 등이 선정되었다. 결론적으로 한반도와 대륙철도 연계 및 복합운송 활성화를 위해서는 첫째, 국경에서의 궤간 변경을 원활하게 하기 위한 환적 시스템 개발을 국제 공동으로 실시해야 하고, 둘째 남 북 중 러 철도시설 및 운영시설을 표준화해야 하며, 셋째, 통관간 소화, 정기 발차, 운임 변동 정보 공유 등을 위한 남 북 중 러의 국제협력이 필요하고, 마지막으로 정부 차원에서 블록트레인 구성을 위한 물량 확보 방안을 마련하고 새로운 비즈니스 모델을 개발해야 할 것으로 판단된다.

• 한국기계가공학회지
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• 제15권6호
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• pp.9-15
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• 2016

Due to material-specific vulnerabilities, the surfaces of the liquid crystal glasses used in mobile phones can crack easily, with even the smallest cracks undergoing propagation. To protect the glass surfaces, films are attached to the surfaces during the mobile phone production process. However, after machining the liquid crystal, removal of the film on the liquid crystal surface using chemical and mechanical methods is required. In this research, a peeling apparatus was developed for removing the films attached to liquid crystal surfaces during the production process. Mechanical attachment and design automation through experimentation and finite element modelling were performed to confirm the validity of the design.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권2호
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• pp.104-111
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• 2010

The complete avoidance of cavitation, as a result of gap flow between the fixed and movable portion of a horn type rudder system, is difficult. To reduce gap flow, it is a common practice to attach a half round prismatic bar that protrudes beyond the concave surface of the horn facing the gap and laid along the centerplane of the rudder. However the employment of such a device does not always yield satisfactory results. Previously, the authors have shown that a pair of blocking bars, attached on the convex surface of the movable portion, better enhance the blocking ability of gap flow to that of a single centre bar installed on the concave surface. This also circumvents difficulties that might occur in practical applications. In the present study, a series of numerical computations show that flow injected into the gap of a rudder may also block the flow within, without employment of any physical devices, such as a half circular bar. This study also shows that the combination of flow injection and blocking bars may result in the synergic augmentation of blocking efficiency of gap flow, as demonstrated in computations for a three dimensional rudder system.

• 한국항해항만학회지
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• 제28권10호
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• pp.891-897
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• 2004

본 연구에서는 수직블록배치형태를 가지는 자동화 컨테이너 터미널을 대상으로 안벽과 야드의 연계작업을 수행하는 이송장비에 대한 시뮬레이션 모델을 수립하였다. 일반적으로 컨테이너 터미널은 안벽장비의 생산성으로 효율성이 평가되며, 안벽장비의 생산성을 최대화하기 위해서는 이송장비와 야드장비의 원활한 지원이 이루어져야 한다. 이중 이송장비는 안벽장비와 직접적으로 연계작업을 수행하므로 안벽장비의 생산성에 많은 영향을 미치는 요소이며, 운행대수와 주행방식에 따라 작업성능 또한 매우 달라지게 된다. 따라서, 본 연구에서는 이송장비의 작업생산성을 평가할 수 있는 시뮬레이션 모델을 개발하였으며, 수립된 모델을 통해 가상의 환경에서 다양한 이송장비의 운영에 따른 안벽장비의 생산성을 분석해 보았다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.131-142
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• 2000

Facility layout is the early stage of system design that requires a mid-term or long-term plan. Since improper facility layout might incur substantial logistics cost including material handling and re-installment costs, due consideration must be given to decisions on facility layout. Facility layout is concerned with low to arrange equipment necessary for production in a given space. Its objective is to minimize the sum of all the products of each equipment's amount of flow multiplied by distance. Facility layout also is related to the issue of NP-complete, i.e., calculated amounts exponentially increase with the increase of the number of equipment. This study discusses Hybrid GA developed, as an algorithm for facility layout, to solve the above-mentioned problems. The algorithm, which is designed to efficiently place equipment, automatically produces a horizontal passageway by the block, if a designer provides the width and length of the space to be handled. In addition, this study demonstrates the validity of the Algorithm by comparing with existing algorithms that have been developed. We present a Hybrid GA approach to the facility layout problem that improves on existing work in terms of solution quality and method. Experimental results show that the proposed algorithm is able to produce better solution quality and more practical layouts than the ones obtained by applying existing algorithms.

• 대한조선학회 특별논문집
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• 대한조선학회 2008년도 특별논문집
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• pp.68-75
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• 2008

This paper describes the design and implementation of a low cost inertial navigation system(INS) using an inertial measurement unit(IMU), a digital compass, GPS, and an embedded system. The system has been developed for a transporter that load and unload ship blocks in a shipbuilding yard. When the transporter would move from place to place, they would periodically pass under obstructions that would obscure the GPS signal. This increases the error when estimating the position. Thus the INS has been used to improve position accuracy. INS is also capable of providing continuous estimates of the transporter's position and orientation. Even though IMU is typically very expensive, this INS is made of "low cost" components and the indirect Kalman filtering algorithm.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.1-10
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• 2021

In this paper we proposed the alternative analysis of reliability design using redundancy technique. First, we presented the process for establishing the reliability design alternative analysis process considering the active redundancy and the standby redundancy. and then, the case analysis of A driving equipment was performed in accordance with the reliability design alternative analysis process presented. In case the series reliability design result is not met with the reliability target value. so, the target item for redundancy design of A driving equipment were selected as items with a severity of two or higher. The redundancy design applied with active and standby redundancy techniques were analyzed using BlockSim software. As a result, it was analyzed that reliability design to active redundancy with one of two elements required for A driving equipment is the most efficient compared to the target value of reliability. The results of this study can be usefully used before the reliability design is performed.

• 산업경영시스템학회지
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• 제41권4호
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• pp.179-188
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• 2018

Recently, blockchain technology has been recognized as one of the most important issues for the 4th Industrial Revolution which can be represented by Artificial Intelligence and Internet of Things. Cryptocurrency, named Bitcoin, was the first successful implementation of blockchain, and it triggered the emergence of various cryptocurrencies. In addition, blockchain technology has been applied to various applications such as finance, healthcare, manufacturing, logistics as well as public services. Distributed consensus algorithm is an essential component in blockchain, and it enables all nodes belonging to blockchain network to make an agreement, which means all nodes have the same information. For example, Bitcoin uses a consensus algorithm called Proof-of-Work (PoW) that gives possession of block generation based on the computational volume committed by nodes. However, energy consumption for block generation in PoW has drastically increased due to the growth of computational performance to prove the possession of block. Although many other distributed consensus algorithms including Proof-of-Stake are suggested, they have their own advantages and limitations, and new research works should be proposed to overcome these limitations. For doing this, above all things, we need to establish an evaluation method existing distributed consensus algorithms. Based on this motivation, in this work, we suggest and analyze assessment items by classifying them as efficiency and safety perspectives for investigating existing distributed consensus algorithms. Furthermore, we suggest new assessment criteria and their implementation methods, which can be used for a baseline for improving performance of existing distributed consensus algorithms and designing new consensus algorithm in future.

• 한국포장학회지
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• 제29권1호
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• pp.1-7
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• 2023

본 연구에서는 PEBAX/PEG-CA 복합필름을 제조하여 내부에 아염소산나트륨 분말을 포함한 스마트 샤쉐를 제작하였다. 또한, TGA, DSC, FT-IR, UV-vis를 통해 샤쉐의 화학적 구조 및 열적 특성과 더불어 샤쉐 적용성 평가를 위해 이산화염소 가스 방출량을 측정하였다. PEBAX/PEG-CA 복합필름은 친수성 및 혼화성을 바탕으로 매트릭스 내에서 강한 화학적 상호작용을 하는 것을 확인하였다. 특히, 구연산의 함량이 높아질수록 복합필름의 열 안정성이 저하되었지만, 저온 및 상온의 유통환경과 필름 제작 온도 범위(<℃)에서 열분해가 발생하지 않았으므로 샤쉐의 제작 및 적용이 가능할 것으로 사료된다. 본 연구의 핵심인 이산화염소 가스 방출량 측정에서는 스마트 샤쉐가 측정 기간인 14일 동안 내부 아염소산나트륨의 이산화염소 가스 방출을 지속적으로 활성화했으며, 산층의 구연산 함량이 높아짐에 따라 방출량이 증가하는 것을 확인하였다. 따라서, 스마트 샤쉐 내부의 아염소산나트륨 함량 및 산층의 구연산 함량 조절 또는 포장크기의 변경 등을 통해 이산화염소 방출량을 효과적으로 조절할 수 있으며, 이는 별도의 설비 및 고가의 장비 없이도 살균 효과를 연장시키는 이점이 있다. 위 실험 결과에 따라 제품 특성 및 포장 용적에 따라 스마트 샤쉐의 응용 적용이 가능할 것으로 판단된다. 하지만, 확실한 소비자 안정성 확보와 스마트 샤쉐의 적용 확장성을 확인하기 위해 항균성 및 저장성 측면에서 향후 연구가 필요하다.

• 대한산업공학회지
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• 제35권1호
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• pp.58-72
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• 2009

The main activities of container terminals are to load container freights to vessels, discharge them from vessels, and store them in the storage yard. Container terminals make many operational plans to execute these functions effectively. If the plans do not consider enough the loads of related resources, they may have low actualities. This study discusses the optimal yard planning model which considers various resources, such as the storage yard, yard cranes, internal vehicles, and travel lanes, in container terminals. The model determines the groups and amounts of containers which are stored in each storage block by using the resource profile. The yard planning problem is represented to the multi-commodity minimal cost flow problem and is formulated to the linear programming model. In order to explain the application of the mathematical model, the numerical examples are presented. Additionally, the relationship between the average load ratio and the relocation ratio is discussed.