• Journal of Ocean Engineering and Technology
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• v.32 no.3
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• pp.158-165
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• 2018

Generally, container ships contain cargo holds with cell guides that serve to increase the container loading and unloading efficiency, minimize the space loss, and fix containers during the voyage. This paper describes a new quality management system for the cell guides of container ships (the so-called Trim Cell Guide system). The main functions of this system are the trimming of the point cloud obtained using a 3D scanner and an inspection simulation for cell guide quality. In other words, the raw point cloud of cell guides after construction is measured using a 3D scanner. Here, the raw point cloud contains a lot of noise and unnecessary information. Using the GUI interface supported by the system, the raw point cloud can be trimmed. The trimmed point cloud is used in a simulation for cell guide quality inspection. The RANSAC (Random Sample Consensus) algorithm is used for the transverse section representation of a cell guide at a certain height and applied for the calculation of the intervals between the cell guides and container. When the container hits the cell guides during the inspection simulation, the container is rotated horizontally and checked again for a possible collision. It focuses on a system that can be simulated with the same inspection process as in a shipyard. For a practicality review, we compared the precision data gained from an inspection simulation with the measured data. As a result, it was confirmed that these values were within approximately ${\pm}2mm$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.466-475
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• 2010

This study intends to present a direction for the better reforming of fishers'onboard living conditions and proposals for preparing for ratification of the Work in Fishing Convention by means of making a comparison between standards on recent national fishing vessel accommodation facilities and standards on the Work in Fishing Convention and Its Recommendation, 2007, ILO. For the most part of standards on national fishing vessel accommodation facilities are somewhat insufficient to satisfy the provisions in Annex III of the Convention. Considering by items on fishing vessel accommodation facilities, the standards on insect protector, noise and vibration, heating and air conditioning, lighting, persons per sleeping room, recreational facility are not provided in national law. Headroom, separation of accommodation, sleeping room floor area, mattress size, mess room, galley and food storage are partially sufficient for the Convention. In case of sanitary facilities, national standards are not sufficient for the Convention. The other side, facilities related safety of ship and crew such as emergency escape etc., are fully sufficient for the Convention. These insufficiencies caused by different types of fishing vessel depend on originality of fishing method and practices. In the comparison between equivalent tonnage about vessel's length on convention and calculated tonnage of national existing fishing vessel, the difference are 226tons about length 24m and 501tons about length 45m. For that reason, headroom, persons per sleeping room, cabin of sicker and injured, sanitary facilities may decide to use gross tonnage in place of length (L) and the alleviating measure basis of convention. But in case of standards on sanitary facilities which are unsufficient for the Convention, specially in coastal fishing vessel length basis should be adopted with alleviating basis for less than length 24m.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.8-16
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• 1993

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• 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 Power System Engineering
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• v.18 no.6
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• pp.180-185
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• 2014

Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it's being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.33-38
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• 2018

This paper introduces the simulation concepts and technical approach of wire-guided torpedo performance analysis simulator, as a consequence, provide a framework for understanding overall attack procedures and effectiveness of tactics to torpedo operator. It described the mathematical models of simulation components and weapon engagement principle, especially it derived the closed-form solution of time consumption and leading angle problem of torpedo attack situation based on geographical assumption. In addition, it adopted the proportional navigation guidance at final stage of torpedo attack and also consider the tradeoff relation between target ship speed(propeller noise level) and detection probability, so that it improves the fidelity of physical realism. Simulator is developed with high degree of freedom in the perspective of tactical situation, and it helps user to understand the overall situation and tactical effectiveness.

• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.278-289
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• 2021

In this study, the acoustic performance of a dissipative silencer used in the ship with excellent performance compared to its size was predicted and analyzed using a numerical analysis method to reduce the pipe noise. To this end, the performance of the single expansion chamber-shaped silencer was verified using experimental and numerical analysis methods. The acoustic performance of the silencer was expressed using the Transmission Loss (TL), an indicator of its own performance, and the result was derived using the two-load method, which measured by changing the impedance at the end of the pipe. For the numerical analysis method, a general-purpose finite element analysis program was used, and the Delany-Bazley-Miki model with the flow resistivity of the sound absorbing material as an input parameter was applied. Finally, we compared the experimental and simulated results for each of the acoustic performances of the single expansion type and the dissipative silencer to confirm the consistency of the results, and predicted and analyzed the simulation results for four cases according to the properties of the sound absorbing material.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.57-65
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• 2022

International attempts to smuggle narcotics and explosives using ship or aircraft cargoes are on the rise. With the recent increase in the number of detection cases of narcotics and explosives in Korea, it is important to detect dangerous material (narcotics and explosives) through container searches at ports and airports, which are the main routes. This paper proposes a technique to detect dangerous material in cargo containers using the sampled output signal of ion mobility spectroscopy (IMS). The proposed technique estimates parameters such as a threshold, a window length, and a noise level for ion detection of the target dangerous material by using known materials in the initialization stage. The estimated parameters are used to detect the ions of the dangerous target material inside the containers. The proposed technique can be applied when the peak value of the IMS signal and the ion mobility are varying due to container environments.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.185-198
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• 2022

Purpose : We conducted a study to propose comparing subjective sleeping states data that was collected through scientifically measuring by using smartwatch and surveys for seafarers. In addition, we conducted a study to provide sleep though analysis of the environmental factors that influence the sleep efficiency of seafarers. Methods : For scientific measurement of seafarers' sleeping states, we measured the sleep hours and sleep efficiency for at least 3 days by using the healthcare function of smartwatches which are wearable devices. As for subjective sleeping states, we collected data on sleep hours and satisfaction rates on the quality of sleep through a survey. Lastly, as for the environmental factors that affect the sleep efficiency which is measured by smartwatches such as physical environment, bedroom space, bedroom furniture, bedding, a survey by self-evaluation method was conducted. Results : There were significant differences in the scientific sleep hours measurement values for all seafarers and the average sleep hours in the subjective survey. There were significant differences in the scientific sleep efficiency measurements of all the seafarers and the sleep satisfaction of the subjective survey, and there was no correlation between the scientific sleep efficiency and the subjective sleep satisfaction of all the seafarers. Among the environmental factors affecting the sleep efficiency of the seafarers, humidity variable had the most influence, and vibration and illuminance variables were also shown to have a very significant effect. Conclusion : We propose the measuring method that can analyze the quantitative and qualitative sleep states of the seafarers by using small activity recorders. In addition, it is very important to control humidity, vibration, and illuminance among ship environmental factors, and comfort, noise and bedroom size should also be reflected.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.51-59
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• 2023

The tracking radar system is installed and operated on the ground, ships, and aircraft, and requires a design to withstand electromagnetic interference with nearby electronic devices. In this case, radiation and immunity standards for cable connection must be satisfied to prevent malfunction of other equipment due to electromagnetic wave interference caused by cables connected to the tracking radar. The radiation standard must also be satisfied so that the electromagnetic wave noise generated and radiated from the tracking radar does not affect the peripheral device, so that the immunity standard for the electromagnetic wave emitted from the peripheral device must be satisfied. In this paper, we propose a design to satisfy MIL-STD-461G including CE, CS, RE, and RS, and explain design satisfaction through tests.