• Journal of the Korea Academia-Industrial cooperation Society
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• 제15권10호
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• pp.5919-5924
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• 2014

Accumulated dross adhered to the cutting support degrades the cutting accuracy and aggravates the working environment by reducing the efficiency of the dust collector. Furthermore, the cutting machine and product can be damaged by the scattering of molten metal. In this study, an attempt was made to increase the productivity of steel cutting process and improve the working environment by dross control. The dross adhesion characteristics were invested by a cutting experiment and the design concept for a dross removal machine was devised. Finally, a cutting support cleaning system and its operating algorithm were developed. The applicability of the developed system was examined and verified by a long-term field test after installation of the plasma arc cutting system of a shipyard.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제13권8호
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• pp.3806-3813
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• 2012

The coastal environment is affected by Cu and Zn contamination through diverse routes, including antifouling agents, industrial wastewater, and domestic activities. In this study, Crassostrea gigas and Littorina brevicula were used to examine the distributions of Cu and Zn, which are related to the increase in the use of new antifouling agents that have been used for ships since the TBT ban in 2003. The average Cu and Zn concentrations in the samples were 231.8 ${\mu}g/g$ and 492.6 ${\mu}g/g$, respectively. Both the Cu and Zn concentrations were highest in the shipyard samples, followed by the harbor sample for Cu and the industrial area sample for Zn. The results indicated that the Cu concentration was affected by the antifouling agents, and the Zn concentration was affected by both the antifouling agents and industrial wastewater. The areas that need intensive control to address the Cu and Zn contamination in major Korean coasts were identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권10호
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• pp.426-431
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• 2016

In quay processes in shipyards, it is difficult to manage workers and to maintain secure working environments because at least 1,000 people can occupy the quay at the same time. In this study, a system was designed to monitor the environment and processes of quay operation. In order to lower initial investments and the costs of maintenance and operation, the entire system consists of six connected components. Considering the communication environment of the shipyard site, Wi-Fi and the LoRa communication protocol were selected for the system. The feasibility of the communication protocols was verified by data transmission tests in the field. The designed system can provide real-time information about employees working in the quay area, the safety status of moored ships on the quay, and step-by-step alarms in dangerous situations based on the detected information. The system is expected to prevent or greatly reduce safety hazards.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제12권2호
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• pp.352-359
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• 2008

RTLS(Real Time Location Systems) is a technology that identifies a location of a target object and provides peat visibility at a work place. Unlike those of the overseas, domestic ports and shipyards have narrow work places and thus, the efficient utilization of these spaces is one of the most important considerations for improving productivity. Companies considering implementation of RTLS should understand its limitations or applicability. In this paper, problems of RTLS such as fading factors which were caused from the features of RF, and limitations caused from the preconditions of RTLS were explained. To overcome those problems, three types of solutions such as movable RTLS, semi-movable RTLS and combined RTLS with other technologies were suggested.

• Journal of the Society of Naval Architects of Korea
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• 제38권3호
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• pp.54-61
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• 2001

It is expected that ISO issue a standard method for sea trial and the correction of data taken during speed trial. One of the major reason for this effort(or trend) is to get reliable and accurate sea trial measurement. With the same philosophy, SHI(Samsung Heavy Industries) developed a nautical signal integrated unit in 1996. Two years after this, SHI developed a software that enable the user to analyze the sea trial measurement on-board. After a series of stationary and performance tests, KR has issued a certificate for international application of the software. We have been utilizing this program for the measurement and analysis of sea trial of more than 70 ships built in SHI shipyard. However, one critical defect of the software has been that it can be applied only for single shaft vessels. In this short paper, we would like to introduce a new version of the software which can be used for both single and multi thruster vessels. This paper deals with the introduction, test method and some of the test result.

• Journal of the Society of Naval Architects of Korea
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• 제53권2호
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• pp.115-126
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• 2016

In the process of ship building, it is known that the maintenance of working period and saving cost are one of the important part during the logistics of blocks transportation. Precise operational planning inside the shipyard plays a big role for a smooth transportation of blocks. But many problems arise in the process of block transportation such as the inevitable road damage during the transportation of the blocks, unpredictable stockyard utilization of the road associated with a particular lot number, addition of unplanned blocks. Therefore, operational plan needs to be re-established frequently in real time for an efficient block management. In order to find the shortest path between lot numbers, there are several representative methods such as Floyd algorithm that has the characteristics of many-to-many mapping, Dijkstra algorithm that has the characteristic of one-to-many mapping, and the A* algorithm which has the one-to-one mapping, but many authors have published without the mutual comparisons of these algorithms. In this study, some appropriate comparison have been reviewed about the advantages and disadvantages of these algorithms in terms of precision and cost analysis of calculating the paths and planning system to operate the transporters. The flexible operating plan is proposed to handle a situation such as damaged path, changing process during block transportation. In addition, an operational algorithm of a vacant transporter is proposed to cover the shortest path in a minimum time considering the situation of transporter rotation for practical use.

• Journal of the Society of Naval Architects of Korea
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• 제53권2호
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• pp.135-143
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• 2016

In this study, an embedded system composed of equipment setting, block importing, scenario setting and output reporting is developed in multi-body dynamics program, ADAMS, for conducting dynamic structural analysis of block lifting process. First, equipment used for block lifting process is set in the simulation environment and the shapes and functions of two lifting beams, and six block loaders are provided as the equipment. Second, the modal analysis result of the lifting block is imported from the static structural analysis system, NASTRAN. Third, the lifting scenarios, such as hoisting, waiting, trolley moving, and wire connecting, are set in the system. Finally, output results in the forms of plots, texts and tables, are reported after the dynamic structural analysis. The test examples conducted in a shipyard are applied into the developed system in various condition and scenarios. The loads at the lug points, the stress contours, and the hot spot tables of the developed system are compared with the result of the static analysis system.

• Special Issue of the Society of Naval Architects of Korea
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• 대한조선학회 2015년도 특별논문집
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• pp.46-49
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• 2015

Common Structural Rules (CSR) about bulk carriers and double-hull oil tankers of International Association of Classification Societies (IACS) has been applied to ships contracted for construction since April 2006. By unifying each society's rules, the difference of opinion in the between shipyard and ship owners, classification was reduced, and CSR has been evaluated by rules the safety structure more enhanced. However, The CSR about the bulk carriers and double hull oil tankers, important design content standards, such as the local scantling calculation, static/dynamic load case and corrosion margin and etc., are different. Therefore in order to combine the CSR, the Harmonized CSR for bulk carriers and double hull oil tankers (H-CSR) was issued on 1, January, 2014, and will be apply to ships contracted for construction after 1st July 2015. It is necessary to verify the H-CSR to optimize the structural arrangement because effective date is not far off. In this study, we compared the impact by rule change for the hull girder shear strength of bulk carriers between CSR and H-CSR in respect of the yielding and buckling strength.

• Journal of the Society of Naval Architects of Korea
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• 제58권2호
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• pp.84-89
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• 2021

Recently, shipyards are making many efforts to reduce the number of the mounted blocks by increasing the block size. This is to improve productivity and reduce related costs by minimizing block movement and shortening the building period. However, as the blocks become larger, the weight increases considerably. If the target block has a damage due to an unexpected accident during block lifting, it may seriously cause a problem of the reusability of the block. In this study, a large-sized block of the offshore structure weighing 480 tons was lifting with a total of seven sling belts, and one sling belt was broken while it was moving, resulting in a situation in which a part of the edge of the block collided with the ground. The aim of this paper is to verify the structural integrity of the block that directly collides with the ground in the form of free fall due to the sling breakage. Considering that the hook loads acting on several sling belts holding the block are redistributed when a sling belt is broken, the hook loads were recalculated at the angle just before the sling breakage. These loads were used to check the safety of the sling belts. In addition, FE analysis was performed by calculating the amount of impact from the free fall condition, obtaining the impact area by using Hertz's contact theory, and then applying the impact load to the area.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제19권1호
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• pp.171-178
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• 2019

Korea's shipbuilding industry is in a critical condition due to changes in the domestic and international environment. To overcome this crisis, preemptive development of products and technologies through prediction of new demand for ships is necessary. The goal of this research is to develop an artificial intelligence algorithm based on ship big data in order to predict new demand for ships. We intend to develop a big data analytics platform specialized in predicting ship demand and to utilize the forecast results of new ship demand through data analysis for planning/development of new products. By doing so, the development of sustainable new business models for equipment and equipment manufacturers will create new growth engines for shipyard and shipbuilders. Furthermore, it is expected that shipbuilders will be able to create business cases based on measurable performance, plan market-oriented products and services, and continuously achieve innovation that has high market destructive power.