• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.471-474
• /
• 2006

Several planktonic dinoflagellates, including Cochlodinium polykrikoides (p), are known to produce red tides responsible for massive fish kills and serious economic loss in turbid Northwest Pacific (Korean and neighboring) coastal waters during summer and fall seasons. In order to mitigate the impacts of these red tides, it is therefore very essential to detect, monitor and forecast their development and movement using currently available remote sensing technology because traditional ship-based field sampling and analysis are very limited in both space and temporal frequency. Satellite ocean color sensors, such as Sea-viewing Wide Field-of-view Sensor (SeaWiFS), are ideal instruments for detecting and monitoring these blooms because they provide relatively high frequency synoptic information over large areas. Thus, the present study attempts to evaluate the red tide index methods (previously developed by Ahn and Shanmugam et al., 2006) to identify potential areas of red tides from SeaWiFS imagery in Korean and neighboring waters. Findings revealed that the standard spectral ratio algorithms (OC4 and LCA) applied to SeaWiFS imagery yielded large errors in Chl retrievals for coastal areas, besides providing false information about the encountered red tides in the focused waters. On the contrary, the RI coupled with the standard spectral ratios yielded comprehensive information about various ranges of algal blooms, while RCA Chl showing a good agreement with in-situ data led to enhanced understanding of the spatial and temporal variability of the recent red tide occurrences in high scattering and absorbing waters off the Korean and Chinese coasts. The results suggest that the red tide index methods for the early detection of red tides blooms can provide state managers with accurate identification of the extent and location of blooms as a management tool.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.331-336
• /
• 2008

Engine builders have separately developed and applied torsional, axial and structural vibration monitoring system on most marine engines. These systems displayed their results for engine or ship operation engineers and were not regularly stored at the hardware of computer. So, tile history and trend of various engine and hull vibrations was not supported for preventive maintenance and to protect the failure of these activity or function. The integrated vibration or stress monitoring system(EVAMOS : Engine/Rotor Analysis and monitoring System) in marine diesel engine, its machineries and hull have been developed by the dynamics laboratory of Mokpo Maritime University during last 3 years. This paper introduces tile design conception and ability of commercial software EVAMOS with field data on several actual tests.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.2
• /
• pp.50-55
• /
• 2017

This study is about the distributions of flow in an air conditioning duct used for marine and oil drilling ships. Three-dimensional steady state turbulence was assumed as a governing equation for describing the flow in the air conditioning duct in this study. We compared the flow field with the pressure distribution according to the inlet velocity for two types of air conditioning duct, and stress and safe factors were simulated using ANSYS W/B. The result of fluid analysis showed an increased pressure drop in the duct according to the inlet velocity. Furthermore, secondary flow and complicated flow characteristics occurred at the bellows zone.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.635-638
• /
• 2000

It is necessary to work on a vertical plane of workpiece in order to produce a large structure like a ship. These works can be automated by using the robot with permanent magnet wheels. We developed the permanent magnet wheel which can be used by a mobile robot and easily detached. We enhanced an adhesive power by restricting the occurrence direction of magnetic flow. And we also developed a method which weakens adhesive magnetic force by changing magnetic flow with metal pins. We used the load cell and the gaussmeter to measure the characteristics of the adhesive force and magnetic force. We obtained the result that the adhesive power is reduced to 1/3 of normal state by using 4 inducing pins.

• Journal of Ship and Ocean Technology
• /
• v.10 no.3
• /
• pp.1-16
• /
• 2006

Despite the high cost of memory and CPU time required to resolve the boundary layer, a viscous unstructured grid solver has many advantages over a structured grid solver such as the convenience in automated grid generation and vortex capturing by solution adaption. In present study, an unstructured Cartesian grid solver is developed on the basis of the existing Euler solver, NASCART-GT. Instead of cut-cell approach, immersed boundary approach is applied with ghost cell boundary condition, which can be easily applied to a moving grid solver. The standard $k-{\varepsilon}$ model by Launder and Spalding is employed for the turbulence modeling, and a new wall function approach is devised for the unstructured Cartesian grid solver. Developed approach is validated and the efficiency of the developed boundary condition is tested in 2-D flow field around a flat plate, NACA0012 airfoil, and axisymmetric hemispheroid.

• Journal of Ship and Ocean Technology
• /
• v.4 no.3
• /
• pp.33-45
• /
• 2000

A computational system for wave and viscous flow analysis (WAVIS) has been developed. The system includes a pre-processor, flow solvers and a post-processor. The pre-processor is composed of full form presentation, surface mesh and field grid generation. The flow solvers are for potential and viscous flow calculation. The post-processor has graphic utility for result analysis. All the programs are integrated in a GUI-launcher package. To validate the developed CFD programs of WAVIS, the calculated results for modern commercial hull forms are compared with measurements. It is found that the results from WAVIS are in good agreement with the experimental data, illustrating the accuracy of the numerical methods employed for WAVIS.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.554-558
• /
• 2004

In this paper, we introduce noise prediction program of HVAC system to assist low-noisy design of ship's cabin. The developed program calculates sound power levels at HVAC components considering primary and secondary noise generated by fan and duct element, duct element noise attenuation, and duct break-in noise based on the authentic empirical method suggested by NEBB and acoustic power balancing method. Sound pressure level at cabin with or without ceiling system is evaluated by the diffuse-field theory considering diffuser and duct break-out sound powers. Moreover, the program provides intuitive pre- and post-processors using modem GUI functions to help efficient modeling and evaluation of cabin and HVAC component noise. To validate the accuracy and convenience of the program, noise prediction for a HVAC system is demonstrated.

• Journal of the Korean Society of Visualization
• /
• v.19 no.2
• /
• pp.48-55
• /
• 2021

In order to design a propeller with high efficiency and excellent cavitation performance, theoretical and experimental studies on the cavitation and noise characteristics according to the blade section shape are essential. In general, sheet cavitation, bubble cavitation, and cloud cavitation are the main causes of hull vibration and propeller surface erosion. However vortex cavitation, which has the greatest influence on the noise level because the fastest CIS in ship propeller, has been researched for a long time and studies have been conducted recently to control it. In this experiment, the development process of cavitation was measured by using three dimensional wings with two different wing section and wing tip shapes, and the noise level at that time was evaluated. In addition, we evaluated the relationship between cavitation inception and hydrodynamic force using three component load cell and we measured the velocity field of wing wake using LDV.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.18 no.4
• /
• pp.41-46
• /
• 2022

In the fourth industrial era, when various technologies are fused and combined, new and advanced technologies from other industries are used extensively in the maritime industry field. New security threats are also increasing along with the development of new technologies. In addition, in incorporating convergence technologies into the maritime industry, various problems, such as communication definitions and procedures between technologies and customer-customized delays, occur. In this paper, for the problems mentioned above, research results on the network configuration of safer autonomous vessels by supplementing and fusing existing solutions rather than developing new technologies are proposed. In conclusion, the entire network consists of VDI and presents additional configurations to ensure confidentiality, integrity, and availability, which are the three security elements. According to the composition of such a convergence network, it is intended to help prepare countermeasures to protect internal data from external threats.

• Journal of Navigation and Port Research
• /
• v.47 no.6
• /
• pp.394-400
• /
• 2023

Unlike advancements on land, the maritime industry has been slow to embrace new technologies, primarily due to user apprehension toward unproven innovations in the development process. The existing paradigm of technology development, marked by expert-oriented and laboratory-centric test environments, often leads to a stagnation of progress at the research stage, as the applicability of the technology remains uncertain. This study departed from the conventional research system and introduced a novel methodology known as a "living lab." This approach aimed to ensure applicability by actively involving field-oriented users throughout the entire lifecycle of technology development, encompassing planning, development, verification, and evaluation. The presentation of a plan for the construction and operation of such a living lab in this study is expected to contribute to establishing an efficient experimentation system for ships that can reflect user opinions in the future and to secure technology applicability in the maritime field.