• 대한조선학회논문집
• /
• 제59권4호
• /
• pp.225-234
• /
• 2022

The flow field measurement above whole area of the flight deck on 'Landing Platform Helicopter (LPH)' was performed by using PIV system in wind tunnel. In various heading angle conditions (0deg, -30deg, -45deg, -60deg, -75deg and ±90deg), the velocity fields such as U velocity & V velocity were measured at three different height above flight deck. Due to the geometrical characteristics of several bodies like deck, crane and super-structure, various vortex were generated. When the heading angle is 0deg, the deck edge vortex by flight deck and massive separation by super-structure were clearly observed by visualization with smoke and PIV, respectively. In other heading angles, the acceleration of flow in space between crane and super-structure were detected. And area with flow separation by super-structure is directly related to the heading angle of vessel.

• 한국항해항만학회지
• /
• 제30권6호
• /
• pp.465-470
• /
• 2006

최근 선박의 대형화 추세에 따라 항만의 장비 및 시설 또한 대형화 추세에 있다. 특히 이러한 경향은 부산항, 상해항등 대형 Hub-Port의 역할을 수행하는 항만들의 항만 간 경쟁측면에서 두드러지게 나타나고 있다. 최근 6만톤(5,000TEU급) 이상 대형 컨테이너 선박의 발주로 부산항에 기항하는 대형선박의 수가 꾸준하게 증가하고 있다. 그러나 반면, 중소형 선박들의 부산항 기항횟수 또한 증가하여 2만톤 $(1,500TEU\sim2,000TEU)$ 이하인 중소형 선박의 비중이 70%이상을 차지하고 있다. 이러한 현실을 놓고 볼 때 중소형 선박의 하역시설에 대한 고려가 필요함에도 불구하고 이를 지나치게 간과하는 측면이 있다. 장비 및 시설의 대형화는 높은 비용 투자로 인해 중소형 선박 작업 시 높은 하역원가가 적용되므로 중소형 선사는 하역비 부담, 운영사는 중소형 선박 기피와 같은 현상을 가져올 수 있다. 본 연구의 목적은 선박크기, 크레인 규모와 수, 인력구조 등을 반영한 시간가치 비용을 산정함으로써 선박 규모별 컨테이너 1개(VAN)의 하역 비용가치를 분석하여 선박 규모별 투입 크레인과 인력구조의 적정성을 평가하는 데 있다.

• 한국항해항만학회지
• /
• 제33권5호
• /
• pp.353-359
• /
• 2009

국내 컨테이너 터미널의 대부분 컨테이너 처리량에 비해 장치장 규모가 협소한 편이다. 장치장이 협소한 이유는 터미널 개발 시 적용된 이론적인 안벽 처리능력이 실제 처리능력과 차이가 나기 때문이다. 또한 최근 선박이 대형화 되면서 터미널들이 안벽장비를 추가 투입함으로써 안벽 생산성을 당초보다 크게 향상시킨 현실에 기인하기도 한다. 본 연구에서는 터미널 운영 현실을 반영하여 하역 능력을 재산정하고 10,000TEU에 이르는 초대형 선박을 대상으로 하여 소요 장치장 규모를 산정 한 후 기존 터미널의 장치장 규모와 경제성을 비교하는 것을 주목적으로 한다.

• 한국산업보건학회지
• /
• 제25권3호
• /
• pp.301-311
• /
• 2015

Objectives: Operators of overhead traveling crane in a ship assembly factory perform work to transmit large vessel blocks to an appropriate working process. Hazardous matters such as metal dusts, carbon monoxide, carbon dioxide, ozone, loud noise and fine particles are generated by variable working activities in the factory. The operators could be exposed to the hazardous matters during the work. In particular, welding fumes comprised of ultra fine particles and heavy metals is extremely hazardous for humans when exposing a pulmonary through respiratory pathway. Occupational lung diseases related to welding fumes are increasingly on an upward tendency. Therefore, the objective of this study is to assess properly unknown occupational exposure to the welding fumes among the operators. Methods: This study intended to clearly determine an equivalence check whether or not chemical constituents and composition of the dusts, which existed in the driver's cab, matched up with generally known welding fumes. Furthermore, computational fluid dynamics program(CFD) was used to identify a ventilation assessment in respect of a contamination distribution of welding fumes in the air. The operators were investigated to assess personal exposure levels of welding fumes and respirable particulate. Results: The dust in an operation room were the same constituents and composition as welding fumes. Welding fumes, which caused by the welding in a floor of the factory, arose with an ascending air current up to a roof and then stayed for a long time. They were considered to be exposed to the welding fumes in the operation room. The personal exposure levels of welding fumes and respirable particulate were 0.159(n=8, range=0.073-0.410) $mg/m^3$ and 0.138(n=8, range=0.087-0.178) $mg/m^3$, respectively. They were lower than a threshold limit value level($5mg/m^3$) of welding fumes. Conclusions: These findings indicate that an occupational exposure to welding fumes can exist among the operators. Consequently, we need to be keeping the operators under a constant assessment in the operator process of overhead traveling crane.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 2003년도 추계학술대회 및 정기총회
• /
• pp.350-353
• /
• 2003

Navy surface vessels require pier services such as emergency repair, oil supply, fm loading/unloading, crane, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. The study suggests Mixed Integer Programing (MIP) model for bath allocation problem, considering precedence relationships among services. For a effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 3.1 and ILOG Cplex 7.0. The results of the model show reduction of berth shifts and increasement of service benefits. And thus, it would be a possibility of contribution in the improvement of fleet readiness.

• Industrial Engineering and Management Systems
• /
• 제9권2호
• /
• pp.178-194
• /
• 2010

To improve the ship operation in automated container terminals, it is important to schedule different types of handling equipment to operate synchronously. For example, a vehicle with container receiving and lifting capabilities is used to transport containers from a storage yard to a vessel and vice versa, while a triple quay crane (QC) can handle up to three 40-ft containers simultaneously. This paper discusses the manner in which vehicles should be assigned to containers to support such multi-lifts of QCs by using information about the locations and times of deliveries. A mixed-integer programming model is introduced to optimally assign delivery tasks to vehicles. This model considers the constraint imposed by the limited buffer space under each QC. A procedure for converting buffer-space constraints into time window constraints and a heuristic algorithmfor overcoming the excessive computational time required for solving the mathematical model are suggested. A numerical experiment is conducted to compare the objective values and computational times of the heuristic algorithm with those of the optimizing method to evaluate the performance of the heuristic algorithm.

• Ocean Systems Engineering
• /
• 제2권3호
• /
• pp.217-228
• /
• 2012

As the size of container ships continues to increase, not many existing harbors can host the super-container ship due to its increased draft and the corresponding dredging requires huge budget. In addition, the minimization of waiting and loading/offloading time is the most important factor in harbor competitiveness. In this regard, mobile-harbor concept has been developed in Korea to achieve much improved harbor capacity and efficiency. In developing the concept, one of the most important elements is the operability of crane between two or more floating bodies in side-by-side arrangement. The container ship is to be stationed through a hawser connection to an outside-harbor fixed-pile station with the depth allowing its large draft. The mobile harbors with smart cranes are berthed to the sides of its hull for loading/offloading containers and transportation. For successful operation, the relative motions between the two or more floating bodies with hawser/fender connections have to be within allowable range. Therefore, the reliable prediction of the relative motions of the multiple floating bodies with realistic mooring system is essential to find the best hull particulars, hawser/mooring/fender arrangement, and crane/docking-station design. Time-domain multi-hull-mooring coupled dynamic analysis program is used to assess the hydrodynamic interactions among the multiple floating bodies and the global performance of the system. Both collinear and non-collinear wind-wave-current environments are applied to the system. It is found that the non-collinear case can equally be functional in dynamics view compared to the collinear case but undesirable phenomena associated with vessel responses and hawser tensions can also happen at certain conditions, so more care needs to be taken.

• 한국해양공학회지
• /
• 제34권3호
• /
• pp.202-207
• /
• 2020

A track-type underwater construction robot (URI-R) was developed by the Korea Institute of Ocean Science & Technology. Because URI-R uses tracks to move on the seabed, insufficient ground strength may hinder its movement. For smooth operation of URI-R on the seabed, it is important to determine the geotechnical properties of the seabed. To determine these properties, standard penetration test (SPT), cone penetration test (CPT), and sampling are used on land. However, these tests cannot be applied on the seabed due to a high cost owing to the vessel, crane, sampler, and analysis time. To overcome these problems, a free fall cone penetration tester (FFCPT) is being developed. The FFCPT is a device that acquires the geotechnical properties during impact/penetration/finish phases by free fall in water. Depth information is crucial during soil data acquisition. As the FFCPT cannot measure the penetration depth directly, it is estimated indirectly using acceleration. The estimated penetration depth was verified by results of real tests conducted on land.

• Ocean Systems Engineering
• /
• 제1권2호
• /
• pp.157-169
• /
• 2011

To provide more rational design solutions at conceptual design level, axiomatic design method has been applied to solve critical part of a new engineering problem called Mobile Harbor. In the implementation, the Mobile Harbor, a functional harbor system that consists of a vessel with container crane approaches to a container ship anchored in the open sea and establishes a secure mooring between the two vessels to carry out loading and unloading of containers. For this moving harbor system to be able to operate successfully, a reliable and safe strategy to moor and maintain constant distance between the two vessels in winds and waves is required. The design process of automatic ship-to-ship mooring system to satisfy the requirements of establishing and maintaining secure mooring has been managed using axiomatic design principles. Properly defining and disseminating Functional Requirements, clarifying interface requirements between its subsystems, and identifying potential conflict, i.e. functional coupling, at the earliest stage of design as much as possible are all part of what need to be managed in a system design project. In this paper, we discuss the automatic docking system design project under the umbrella of KAIST mobile harbor project to illustrate how the Axiomatic Design process can facilitate design projects for a large and complex engineering system. The solidified design is presented as a result.

• International Journal of Ocean System Engineering
• /
• 제1권4호
• /
• pp.198-204
• /
• 2011

Recently, several problems have occurred in the space, infra-structure, and facility of the contiguity of existing harbors due to the trend of enlarged container vessels. In this regard, the Mobile Harbor has been proposed conceptually in this study as an effective solution for these problems. The concept is that of a transfer loader that transfers containers from a large container ship to the harbor on land, and is a catamaran type floating barge. The catamaran-type vessel is well known for its advantage in maneuverability, resistance, and effectiveness for working on board. For the safe and effective operation of the two floating bodies (a container ship and the mobile harbor in the near sea detached from the quay), robot arms, novel crane systems, and pneumatic fenders are specially devised with an additional mooring facility or DP (dynamic positioning) system. In this study, this concept is to be verified through comparison and simulation studies under various environmental conditions. It is shown that the proposed concept is in general feasible but there are several areas for further investigation and improvement.