• Bulletin of the Society of Naval Architects of Korea
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• v.2 no.1
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• pp.9-14
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• 1965

Ship designers make every efforts to get faster ships in accordance with the development of the Naval Architecture. But for the speed lying over factor length ratio 2.5-3.0, we could put a powerful engine into the conventional round bottom displacement type vessels, but it is very difficult in view point of economy, weight and volume. The principal cause of these speed obstacles is the wave making resistance and researchers are trying to decrease this resistance. One of the resolving ways, planing hulls were applied to small high boats. Planing hull's advantage is not restricted to speed, but the workmanship of the planing hull is easier than those of displacement type vessels of round bottom. Planing hull, therefore, are widely applicable to the intermediate speed boats, which don't have enough high speed to take planing advantage, as well as high speed boats. We will discuss related phenomena of the planing hull in details and this paper we particularly interested in the interjection point(speed length ratio 3.0-3.5 by Mr. D. De Groots) between semi-planing and full planing hulls on the resistance characteristic curve. The paper by Prof. Keuck Chun Kim, "Some Characteristics of Straight Framed V-bottom Hull Forms", Journal of the society of Naval Architects of Korea, Vol.1, No.1, Dec.5, 1964, is referred to the V-bottom hull forms belonging to low speed region and determines practical applicable limit of the speed length ratio combined with construction costs, under which are still used by large commercial vessels. This is the interesting contrast between his and authors. We will further discuss the speed length ratio which is considered as a beginning point to planing effect. For this analysis, we choose 3 model ships: Model (1) and (2) have the same principal dimensions, model 3 varied dimension. Model (1) is full-planing hull, (2) is semi-planing hull and (3) is complete planing hull. They are aimed to collect proper design data for purposed ships.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.133-139
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• 2020

In order to study the resistance test technique for the submerged body in Large Cavitation Tunnel (LCT), DARPA Suboff, submarine model publicly available was manufactured. DTRC released the resistance test data of DARPA Suboff conducted at ship speeds up to 18.0 knots in high-speed towing tank in 1990. As LCT is considered restricted waterways with walls, the resistance test results must be corrected with three wall blockage effects called buoyancy effect, solid blockage effect and wake blockage effect. Before correction, the resistance of LCT was 16~20 % higher than that of DTRC. After correction, the resistance and the resistance coefficients were compared with those of DTRC. The corrected resistance of LCT shows good agreement with that of DTRC. The residual resistance coefficient shows the difference according to the calculation method of buoyancy and frictional resistance coefficient. This paper suggests the best way for the calculation of residual resistance coefficient, On the basis of the present study, it is thought that the operating conditions for the propeller cavitation and noise tests can be drawn through LCT tests.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.4
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• pp.121-133
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• 2008

In manufacturing companies, engineering information is a central data which defines a product to be produced. This is changed by various factors such as changes of product configuration, changes of drawings information of a technology's licensor, etc, and these changes essentially accompany the changes of a product BOM (Bill of Materials) structure. Thus, engineering changes gives a heavy burden to information management within enterprise because the changes of product BOM have an influence on each departmental BOM such as a procurement BOM, a manufacturing BOM, a quotation BOM, etc. Especially, these changes of product BOM due to the engineering changes is inevitably and frequently happened by a customer's requirements in a customer-oriented make-to-order manufacturing environments. In these manufacturing environments, information gap among each department from the first contact point of customer to engineering, materials, production, quality, and management is very close, and thus it is very important that the change information of product BOM due to changes of product specification and engineering information are efficiently communicated among each department. This paper describes a procedure of determining product specification and of generating product BOM, and proposes an efficient management scheme for the change process of product BOM information due to changes of product specification and engineering. Also, to show the effectiveness of the proposed product BOM management scheme, a product BOM management system is implemented for the ship engine division of 'H' company, one of customer-oriented make-to-order manufacturing enterprises.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.523-531
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• 2019

The low birthrate and the need for national defense reform in Korea drive the Navy to develop efficient human resource planning such as a manpower forecasting model. However, to our knowledge, there is no study exploring the manpower forecasting model for naval ships in Korea. The purpose of this paper is to develop a model for forecasting manpower demand in naval ships. Data for analyses were drawn from 19 ships in the Korean Navy. Results indicate that mission type is significantly related to the number of manpower. Specifically, battleships need the more manpower than the battle support ships. The results also showed that the weight of hull structure-engine and the weight of the weapons system significantly increased the number of manpower. However, the weight of the combat system was not significant. In addition, whereas the automation level of hull structure-engine and the automation level of weapon system was found to be negatively related to the number of manpower, the automation level of combat system was positively related to it. The model developed here contributes to an advanced human resource planning of the Korean Navy. Implications, limitations, and directions for future research are discussed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.622-625
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• 2007

Emotional Management refers to the capacity for recognizing our own feelings and those of others, for motivating ourselves, and for managing emotions well in ourselves and in our relationships. Although many of the companies are currently emphasizing that the emotional management is a very important for the management, the study of the emotional management is still extremely passive. This paper is to explain about the reason why emotional management which is becoming an ongoing issue recently should focus less on customers but more on staffs (personnel) in building industries. Furthermore, the paper suggests the required emotional management to the staffs (personnel) with the data from the survey carried out. Finally, this paper is aimed to solve the difficulties that the building industry related would have.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.159-163
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• 2005

Marine accidents of 70.9% have been caused by small ships less than 100 tons in the past 5 years(1998${\sim}$2002). This is ascribable to the graying and lack in expertise on shipping of small ship operators, and merchant ships are hindered from coastal navigation due to the increase of coastal fishing boats and liners. Currently, ECDIS and GPS Plotters are widely used as navigation equipment providing route information to operators, but it can not give any function of automatic route creation and route explanation, so they are available only experienced operators. Especially, the present situation is that no study is made of the automatic route creation and route explanation using ENC for ECDIS, substitution system of paper chart. In this paper, Navigation Guiding System(NGS) is proposed to generate an optimal route where ENC and GPS data is fusioned including the wind speed and direction of anemometer. The proposed system was testified by a simulation, and its effectiveness was verified.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.127-132
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• 2006

Maritime transportation engineering is a technical field that observes the flow of vessel's traffic in accurate and describes the feature of ship's movement statistically, then contributes to the improvement of traffic flow and the safety of traffic. The flow of marine traffic can be controlled by carrying out assessment and analysis of vessel's traffic. It can realize the safety of marine traffic by accurate research and analysis of vessel's traffic, understanding its flow and analysis data of vessel traffic. This study the analysis system of marine traffic connected with Radar, AIS based on ENC(Electronic Navigational Chart). The marine traffic analysis system contributes to safety of marine traffic through the design of marine traffic route, harbour facilities and improvement of vessel's traffic flow.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.43-48
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• 2007

Maritime traffic engineering is a technical field that observes the flow of vessels' traffic in accurate and describes the feature of ship's movement statistically, then contributes for the improvement of traffic flow and the safety of traffic. The flow of marine traffic can be controlled by carrying out assessment and analysis of vessel's traffic. It can realize the safety of marine traffic by accurate research and analysis of vessel's traffic, understanding its flow and analysis data of vessel traffic. This study shows the analysis system of marine traffic connected with Radar, AIS based on ENC(Electronic Navigational Chart). The marine traffic analysis system contributes to the safety of marine traffic through the design of marine traffic route, harbour facilities and improvement of vessels' traffic flow.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.381-388
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• 2017

Recently, renewed attention for technological applications within the maritime industry has taken place, particularly regarding unmanned vessels. There has been a lot of interest about the number of projects aiming at testing the operational feasibility of unmanned vessels, particularly in relation to technological, safety and security issues. Nevertheless, no studies have investigated this issue from the point of view of seafarers towards unmanned vessels; this paper aims at filling this gap. Data has been collected through a survey questionnaire. A Pearson correlational coefficient has been used to test the correlation between some of the variables. The results show that more than half of the respondents indicated that unmanned vessels do not contribute to an increase in accidents at sea. In addition, seafarers believe unmanned vessels will not be operational in the near future, with most of the respondents indicating a 10-20 year time frame. Thirdly, most of the respondents(both officers and ratings).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.1
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• pp.65-75
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• 2002

The changes of sea bottom configuration, which may cause the coastal disasters, have been considered as social problems. It is obvious that the beach deformation is attributable to the sediment transport associated with erosion and siltation in coastal areas such esturies, channel and harbors. The prediction method and countermeasures far them, however, are not on the level of satisfaction, which indicates that make efforts should be made on developing them. Groin was constructed at Hak-Dong gravel beach to embark ship at 1996, as a result region of right of groin, severe erosion of beach is proceeding till now 1999. In this study, based on the field measurements, involved the one-line theory model which was selected for the prediction of shoreline change to prepare coastal protection methods of Hak-Deng gravel beach. Author found that the storaged sediment estimation model by Sonu and Beek(1971) is useful model at the Hak-Dong gravel beach by the use of topographical survey data from September, 1998 to September, 1999.