• Journal of Ocean Engineering and Technology
• /
• v.20 no.5 s.72
• /
• pp.70-76
• /
• 2006

A Probabilistic neural network (PNN) technique for predicting the stability number for the armor blocks of breakwaters is presented. A PNN is prepared using the experimental data of van der Meer and is then compared with the empirical formula and previous artificial neural network (ANN) model. This comparison shows that a PNN can effectively predict the stability numbers in spite of data complexity, incompleteness, and incoherence, and can be an effective tool for the designers of rubble mound breakwaters to support their decision process and to improve design efficiency.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.219-222
• /
• 2009

Green ocean is one of the main issues internationally. Most governments are leading the role in boosting the economy through creating new green market and establishing system of coping with increasing international environmental regulation. Green ocean, which is a solution for the environmental issue of global warming, is applied throughout the industry. Domestic transportation industry including railway is also developing technology for creating green ocean. Transportation must decrease energy consumption at running stages because it shows high environmental loads expecially on using stages during its life cycle. Therefore, There are some tries for developing technologies; new engine through alternative energies, hybrid and lightweight. Railway transportation can not be exception. it is intended for this paper to suggest the direction of manufacturing environmentally friendly railway vehicle through the global warming effect evaluation of several materials being applied to vehicle and comparison of the results.

• Journal of Environmental Science International
• /
• v.23 no.3
• /
• pp.483-492
• /
• 2014

DNA damage such as genotoxicity was identified with comet assay, which blood cell of a marine parrot fish (Oplegnathus fasciatus) was exposed to an acidified seawater, lowered pH gradient making of $CO_2$ gas. The gradient of pH were 8.22, 8.03, 7.81, 7.55 with control as HBSS solution with pH 7.4. DNA tail moment of fish blood cell was $0.548{\pm}0.071$ exposed seawater of pH 8.22 condition, on the other hand, DNA tail moment $1.601{\pm}0.197$ exposed acidified seawater of pH 7.55 lowest condition. The approximate difference with level of DNA damage was 2.9 times between highest and lowest of pH. DNA damage with decreasing pH was significantly increased with DNA tail moment on blood cell of marine fish (ANOVA, p < 0.001). Ocean acidification, especially inducing the leakage of sequestered $CO_2$ in geological structure is a consequence from the burning of fossil fuels, and long term effects on marine habitats and organisms are not fully investigated. The physiological effects on adult fish species are even less known. This result shown that the potential of dissolved $CO_2$ in seawater was revealed to induce the toxic effect on genotoxicity such as DNA breakage.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.10
• /
• pp.1003-1009
• /
• 2012

An instantaneous environmental noise simulation method emitted by a moving high-speed train by quasi-stationary analysis is proposed in this study. In the method, the propagation attenuations from stationary point sources on segmented railways to a receiver are calculated using a general purpose environmental noise prediction program ENPro based on the ISO 9613-2 method. Then, the instantaneous environmental noise at a receiver due to a moving high-speed train considering convection effect is evaluated with the information on the propagation attenuations from the instantaneous train location to the receiver and the sound power levels and directivity of stationary point sources evaluated by German Schall 03 (2006). To demonstrate the validity of proposed method, simulated and measured time history of instantaneous noise for KTX-I and KTX-II on running are compared and the results show that the method can be utilized for the train noise source identification as well as the simulation of instantaneous environmental noise emitted by a high-speed train.

• Journal of Ocean Engineering and Technology
• /
• v.28 no.1
• /
• pp.47-54
• /
• 2014

When an anchor penetrates and is installed under a seabed, a portion of the mooring line connected to the anchor is also embedded under the seabed. This embedded mooring line affects the capacity of the anchor in two ways. First, the frictional resistance that occurs between the mooring line and the seabed reduces the pulling force acting on the anchor. Second, the embedded part of the mooring line forms a reverse catenary shape due to the bearing resistance of the soil, so that an inclined pulling force is applied to the anchor. To evaluate the mooring line's effect on the capacity of an anchor in sand, centrifuge model tests were performed using two relative sand densities of 76% and 51% while changing the anchor depths. The test results showed that the load is reduced much more in deep and dense sand, and the inclination angle of the load is lower in shallow and loose sand.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2003.10a
• /
• pp.163-166
• /
• 2003

Hull form designers have to design a ship with satisfying an economical, technical and environmental demand. When it is concerned by a technical and environmental demand, there will be a economical demand left to criticize optimization. In this case, there were used to be requirements which needs to meet only a best performance not concerning about input of Human resource. Life cycle's cost contains building cost and operation cost so that now we need to check Man Hour cost in building a ship. This research shows a correlation between hull form information, i.e. curvature, length, breadth and thickness of surface and Man Hour of the Shell plating manufacture with using Artificial Neural Network and Gentic Programming. This study will support to classify initial work, to have a high assumption possible through predicting a Man Hour and to provide a guide book to infer a building cost and a economical optimization hull form.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.429-434
• /
• 2002

The Synthetic Aperture Radar (SAR) data are considered to contain the greatest amount of information among various microwave techniques developed for measuring ocean variables from aircraft or satellites. They have the potential of measuring wavelength, wave direction and wave height of the ocean waves. But, it is difficult to retrieve significant ocean wave heights and surface current from conventional SAR data, since the imaging mechanism of ocean waves by a SAR is determined by the three basic modulation processes arise through the tilt modulation, hydrodynamic modulation and velocity bunching which are poorly known functions. Along-Track Interferometric (ATI) SAR systems can directly detect the Doppler shift associated with each pixel of a SAR image and have been used to estimate wave fields and surface currents. However, the Doppler shift is not simply proportional to the component of the mean surface current. It includes also contributions associated with the phase velocity of the Brags waves and orbital motions of all ocean waves that are longer than Brags waves. In this paper, we have developed a new method for extracting the surface current vector using multiple-frequency (L- & C-band) ATI SAR data, and have generated surface wave height information.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2012.06a
• /
• pp.383-385
• /
• 2012

Confined Disposal Facilities(CDF) are an effective and commonly used management option for contaminated dredged material. CDF is an engineered contstruction for containment of contaminated dredged material to control potential releases to the environment. Although the concept is simple, constructing a CDF is a complex and non-standard process. In the process of planning a CDF, many different fields of expertise have to be considered, such as civil engineering, landscaping, chemistry, legislation, social impact, and environmental engineering. This paper provides the concise overview of common guidance on CDF.

• Korean Journal of Computational Design and Engineering
• /
• v.19 no.2
• /
• pp.169-181
• /
• 2014

Recently ships and ocean platforms are becoming increasingly technological, unmanned, and huge. Maintenance and safety monitoring of these products is very important for safety reasons. Therefore, real-time monitoring of safety regions, such as the engine room, and hull structure, and environmental states, like fire and pressure of LNG tanks, is required for the sustainable ships. In this paper, a ZigBee-based wireless sensor network is suggested to monitor ships and ocean platforms effectively. However, this causes some telecommunication problems because these products are made of steel. To resolve this problem, we use the mesh networking of Zig-Bee that can monitor the regions and environmental states consistently. The telecommunication of such a monitoring system is tested on a real container ship and its performance is verified. The real-time monitoring results are displayed on the users' smart devices.

• International Journal of Ocean System Engineering
• /
• v.3 no.4
• /
• pp.209-217
• /
• 2013

This paper presents a mooring design procedure for a floating offshore wind turbine. Offshore environmental data for Jeju are taken from KHOA (Korea Hydrographic and Oceanographic Administration) and used for the environmental conditions in numerical analyses. A semi-submersible-type floating wind system with a 5-MW-class wind turbine studied by the DeepCwind Consortium is applied. Catenary mooring with a studless chain is chosen as the mooring system. Design deliverables such as the nominal sizes of chain and length of the mooring line are decided by considering the long-term prediction of the breaking strength of the mooring lines where a 100-year return period is used. The designed mooring system is verified using a fatigue calculation based on rain-flow cycle counting, an S-N curve, and a Miner's damage summation of rule. The mooring tension process is obtained from time-domain motion analyses using ANSYS/AQWA.