• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.77-81
• /
• 2010

This study carried out hydraulic model test for water circulation system in Cheongna district as part of Incheon Free Economic Zone. Canal way project of Cheongna was planned to establish for environment-friendly water circulation system, improve quality of life and diversification of traffic through using boat as a water-friendly international business city. The navigation canal, There are two intake facility in central park and it can purify water 15,000$m^3$ per day. After purify, water move to 8 facility of water culture area which supplies water in canal way. This process called water circulation system in cheongna. Also, there are several flow induction machine in canal way except south-north way. Therefore, this study will verify about validity of water circulation system's safety through hydraulic model test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.727-730
• /
• 2004

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, three types of MD-ARS, two passive and one active devices, are developed for small ships. After they are installed on the cabin of the small leisure boat, respectively, a series of test is conducted before and after operating them. Through the test, it is confirmed that the roll responses of the ship are pretty well reduced by the system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.24 no.4
• /
• pp.441-445
• /
• 2000

Considering international status of our country as world class ship builder and geographical characteristics encircled by sea in three facets, controlling of air pollutants emission from marine engines becomes more and more important issue in recent days. Implementation of immediate pollutants emission control regulation and standardization of test and certification procedure are required to reduce air pollution from marine engines. But cost increments due to additional equipment of emission control device and development and certification test expenses as well as depreciation of fuel economy should be considered. To satisfy those air pollution reduction and economic requirements, we should make our own interpretation of IMO standard and implementation schedule depending on our country's status. For this purpose we measured NOx emission from small and middle class marine engines to calculate emission factor and total pollutant emission in our country. With the comparison and analysis of other countries emission control regulation we proposed basic data of total emission from marine engine and future emission control standard in our country. According to our estimation, 62% of total NOx emission of marine engines comes from fishing boat and 38% from commercial vessels. The portion of NOx emission from marine engine is 18.6% of whole country NOx emission. Due to the voyage characteristics of middle and large vessel and necessity of international harmonization of marine engine pollutants emission control standard, it is inevitable to adopt IMO standard for middle and large marine engines. But considering technological and cost effect of fishing boat operating in near sea, it is resonable to set a standard within 80% of measured value at the moment and gradually implement the same IMO standard in near future.

• Journal of the Society of Naval Architects of Korea
• /
• v.50 no.4
• /
• pp.240-247
• /
• 2013

Hydrodynamic characteristics of a planing craft are very sensitive to the hull form variations, especially when the craft navigates with high-speed. Therefore, we need to verify hydrodynamic performances of the craft during the process of hull form design. In this paper, motion performances of a 40ft class cruise leisure boat are evaluated by both model tests and theoretical analyses using two different methods. Model tests are carried out at calm sea and regular wave conditions using high speed towing carriage installed in SNU towing tank. Theoretical methods used are a empirical method proposed by Martin (1976) and a potential method based on Rankine panel (DNV, 2010). The results from the theoretical methods are compared with and verified by those of model tests. Results of empirical formula showed somewhat larger motion RAOs and resonant frequencies than those of model tests. Potential based method showed even larger discrepancies with the model test results. From the analyses of comparison results, we could confirm the limitation of each theoretical method and suggest the way of improvement for the better prediction of motion performances.

• Journal of Ocean Engineering and Technology
• /
• v.21 no.3 s.76
• /
• pp.40-45
• /
• 2007

This study was performed to investigate the effect of various propeller tunnel shapes on the propulsion performance of a fishing boat. The propeller tunnel reduces the problem resulting from the open propeller accidentally catching the waste net and cable on the sea, as well as increasing the cruising speed. For 3 different tunnel geometries, the model test is conducted in the circular water channel, and the potential based panel method was applied to analyze the hydrodynamic characteristics of propeller. Also, both results are compared with each other to represent the difference between results of the model scale test and the potential theory. It is expected that these results could be referenced in the design of the propeller tunnel in consideration of the hydrodynamic interaction between the propeller and the tunnel.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.6
• /
• pp.867-874
• /
• 2021

The IoT (Internet of Things) technology is rapidly becoming an important consideration in many engineering fields in the current 4th industrial era. In recent years, the concepts of digital shipbuilding and smart factories have been adopted as trends in shipyards. However, there is active interest in research on implementing autonomous driving in autonomous vehicles and airplanes, which is currently available in commercial form in a limited capacity. The present study is regarding the path-tracking performance of a boat to accomplish an autonomous driving mission using a flight controller (FC) and real-time kinematic (RTK) global positioning system (GPS) based on an open-source Ardupilot; an actual sea test is also performed using this system on a calm lake. The boat's mission is to evaluate the maneuverability of the self-driving process to a specific point and returning to the home position. For a given speed, the difference between the preset mission trajectory and actual operational trajectory was analyzed, and a series of studies were conducted on the applicability of the system to ships. In addition, the movements and maneuverability of the OmniX-type hull with four propellers were investigated, and the driving path-tracking performance was observed to increase by a maximum of 48%.

• Journal of Korea Port Economic Association
• /
• v.37 no.4
• /
• pp.89-102
• /
• 2021

The purpose of this paper is to study the impact of shipping service firm's perceived relational benefits on switching barriers and loyalty focusing on tug boat service. To achieve the purpose of the research, literature survey on existing literature, thesis, research report is performed and also reliability analysis, validity test and multiple regression analysis using SPSSWIN 18.0 is used in this research. To verify a research model and hypothesis, a questionnaire survey among employees of shipping companies and shipping agencies was executed. 76 copies of total 200 copies of questionnaires were collected and the number of questionnaire used for empirical analysis was 76 copies. The main results of the study are summarized as below. First, Hypothesis 1 "shipping service firm's perceived relational benefits has a positive impact on the switching barrier" was supported by this study. Second, Hypothesis 2 "shipping service firm's perceived relational benefits has a positive impact on the loyalty" was supported in this research. Finally, Hypothesis 3 "switching barrier has a positive impact on the customer's loyalty" was also supported. Further research can be extended by adding more questionnaires including more shipping service firms all over the nation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.3
• /
• pp.240-248
• /
• 2016

As a new technical approach, the achievement of an eco-environmental leisure boat with a photovoltaic system is attempted by simultaneously actuating nine photovoltaic solar panels, in association with an applied sail control system by use of wind. In this approach, the photovoltaic system consists of a solar module, an inverter, a battery, and relevant components, while the sail control device is equipped with a sail up/down and mast-turning instrument. Furthermore, this research conducts a performance evaluation of the manufactured prototype and acquires the purposed quantity value and the development purpose items. The significant items-sail up/down speed (seconds) and mast turning angle (degrees)-are evaluated during the performance test. In the process of the performance evaluation, a wind direction sensitivity of 90% and a maximum instant charging power of 900 W were also obtained. In addition, the maximum sail time is evaluated in order to acquire the optimum quantity.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.1
• /
• pp.50-55
• /
• 2010

The ship's heading information of hybrid GPS/EM compass were applied to the AIS of fishing vessel and examined the possibility of accuracy improvement. It is observed 453 each in AIS receiver of land among 3,982 each in AIS Rx/Tx transponder of the test ship at sea, and transmission interval according to the speed of ship is determined the 11.4% good transmitting data of the all information. In results, maximum compass error for the ship's heading of an EM compass was $19.1^{\circ}$. The variance of ship's heading owing to the speed of ship is surveyed. The COG (Course Over Ground) was changed extremely in $180^{\circ}W-179^{\circ}E$ range under 4.9knots, and in $24^{\circ}W-23^{\circ}E$ range over 4.9knots. Finally, using the ship's heading of EM compass and the COG from GPS for the autopilot system of a small fishing boat and the ship's heading information of AIS results in danger on the own ship's navigation safety and leads to make confusion both the others and VTS (Vessel Traffic Service) center. Therefore, the hybrid GPS/EM compass is identified as the best system for a small fishing boat and is allowed to offer continuously a ship's heading information with high accuracy and stability.

• Journal of the Korean Society of Costume
• /
• v.35
• /
• pp.305-324
• /
• 1997

The purpose of this study was to examine aesthetic effects of face type and necklines of one piece dress one of details in clothes on visual evaluation. For this study two set of stages were processed. At first stage data were collected from female college students in Kwang Ju.Chonnam. Subjects between the aged of 18-26 were took pictured of their faces then they were classified into 7 groups That is egg ob-long round square inverted triangle triangle and diamond shapes. At second stage two sets of experimental design were utilized based on the classified face types. A set of design was 5$\times$4 design which involved 5 levels (egg oblong round inverted triangle and diamong shape) of face type and 4 levels(round boat vee and square neckline) of basic neckline. Another set of de-sign also was 5$\times$4 design which involved 5 levels of face type and 4 levels of modified neckline. As experimental treatment the stimulus materials and questionnaires were employed. The qustionnaires were consisted of visual evaluations on the stimulus materials by using semantic differential scale,. The experiments were proceeded through 2 week by 30 subjects composed of gaduate students and staffs in some departments of Clothing and Textiles at college. Data were analyzed by Frequencies Mean Factor Analysis TTest ANOVA and Ducan's Multiple Range Test. The major results were as followed: 1. There were significant aesthetic effects of face type on visual evaluations, Especially egg and inverted triangle shape among the face types were evaluated more aesthetic than the other face shapes. 2. There were signifiant aesthetic effects of the neckline types on visual evaluations, Es-pecially vee neckline among necklines were more aesthetic than the other necklines,. 3. As compared with the basic neckline types and the modified neckline types the modified necklines were assessed more aes-thetically than the basic necklines. 4, The face type and he neckline type were influenced interactively on visual evauations Specifically it showed that oblong round and diamond shape of face type were matched to vee neckline more than the other necklines, Also it showed that the egg and inverted tri-angle shape wee matched to round vee and squre neckline more than boat neckline.