• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.08a
• /
• pp.155-159
• /
• 2004

The International Ship and Port Facility Security (ISPS) Code has come into force on July 7$^{th}$ 2004. It would therefore be prudent that all parties' concerned put in place, methodically, systematically and as soon as possible, all the necessary infrastructure needed to give effect to all the decisions of the Conference. But the ISPS Code doesn't have the details during implementation. For example, how to legislate, administrate\ulcorner How are the data relating to security incident saved\ulcorner So, the author will lay emphasis to expatiate on three aspects in this thesis on the basis of the fact of anti-terrorism at sea.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.829-833
• /
• 2017

Recently, pirate incidents involving passing ships have been continuously occurring in the seas southwest of the Philippines, the Sulu Sea and the Celebes Sea. Pirates in these areas are members of the "Abu Sayyaf Group", which consists of Islamic armed rebels. They have abducted and confined 59 ship crews over the last 13 months to obtain money for group operations. The activities of these pirates, abducting and killing crews, have became a significant threat for marine security in the Sulu and Celebes Seas and for logistic activities in Asia. This study examines and analyzes 22 recent incidents in terms of ships gross tonnage, kind, nationality, incident time, location, etc. The identity of the Abu Sayyaf Group, which has been committing this piracy and represents the de facto power behind the actors responsible, is also unpacked, along with current challenges to resolving these conflicts. Finally, responses passing ships, shipping companies, related countries and the international community should make are proposed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.04a
• /
• pp.402-403
• /
• 2010

Hebei Spirit Oil Spill in the West Coast in 2007 happened catastrophic environment and economy damage. Refer to the limitation of current oil spill response methods. and oil spill response in the Yellow sea coast of korea, effective measures are considered.

• Coupled systems mechanics
• /
• v.2 no.1
• /
• pp.53-83
• /
• 2013

Sea waves induce significant pressures on coastal surfaces, especially on rocky vertical cliffs or breakwater structures (Peregrine 2003). In the present work, this hydrodynamic pressure is considered as the excitation acting on a piezoelectric material sheet, installed on a vertical cliff, and connected to an external electric circuit (on land). The whole hydro/piezo/electric system is modeled in the context of linear wave theory. The piezoelectric elements are assumed to be small plates, possibly of stack configuration, under a specific wiring. They are connected with an external circuit, modeled by a complex impedance, as usually happens in preliminary studies (Liang and Liao 2011). The piezoelectric elements are subjected to thickness-mode vibrations under the influence of incident harmonic water waves. Full, kinematic and dynamic, coupling is implemented along the water-solid interface, using propagation and evanescent modes (Athanassoulis and Belibassakis 1999). For most energetically interesting conditions the long-wave theory is valid, making the effect of evanescent modes negligible, and permitting us to calculate a closed-form solution for the efficiency of the energy harvesting system. It is found that the efficiency is dependent on two dimensionless hydro/piezo/electric parameters, and may become significant (as high as 30 - 50%) for appropriate combinations of parameter values, which, however, corresponds to exotically flexible piezoelectric materials. The existence or the possibility of constructing such kind of materials formulates a question to material scientists.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.2
• /
• pp.109-121
• /
• 2001

This paper describes results of an experimental study to examine the effect of a submerged horizontal breakwater to sea water exchange. Flow measurements were taken by using a PIV(Particie Image Velocimetry) system, and mean currents and wave ellipses extracted through the harmonic analysis are presented. As results, the rates of circulating flow were closely connected with the volume flux of incident waves and the counter-rotating vortex pair was observed at the onshore side of a plate. The dye study showed that incoming sea water and polluted water body mixed up significantly due to turbulent motions induced by a jet-like flow.

• The Journal of the Acoustical Society of Korea
• /
• v.26 no.6
• /
• pp.286-292
• /
• 2007

The dominant source of noise in a sea-connected piping system is usually due to a seawater cooling pump which circulates seawater to operate onboard equipments normally, and so its water-borne noise with some tonal frequencies should be reduced using proper silencers. In order to obtain the transmission loss of water-borne noise silencers experimentally the present paper suggests a transfer function technique that acoustic wave in the piping system is decomposed into its incident and transmitted components when the reflection at the termination of the system exists. Good agreement in the interested frequency range with theory and the proposed technique shows the validity of the technique.

• Journal of Korea Water Resources Association
• /
• v.43 no.10
• /
• pp.843-850
• /
• 2010

By employing multi-directional random waves, a parameter controlling the force acting on a long caisson breakwater is investigated in detail. Both JONSWAP (Joint North Sea Wave Project) and asymmetric directional spectra are adopted for frequency and directional spectra. It is found that the parameter decreases as the length of caisson and the angle of main direction of incident waves increase. Furthermore, the parameter is much similar to that of regular waves as the maximum spreading parameter $s_{max}$ increases. The parameter, however, decreases as asymmetry parameter ${\mu}$ increases when the main direction of incident waves is oblique to the breakwater.

• Nuclear Engineering and Technology
• /
• v.56 no.4
• /
• pp.1480-1489
• /
• 2024

Displacement cascade behaviors of Ti-6Al-4V alloys are investigated using molecular dynamics (MD) simulation. The embedded atom method (EAM) potential including Ti, Al and V elements is modified by adding Ziegler-Biersack-Littmark (ZBL) potential to describe the short-range interaction among different atoms. The time evolution of displacement cascades at the atomic scale is quantitatively evaluated with the energy of primary knock-on atom (PKA) ranging from 0.5 keV to 15 keV, and that for pure Ti is also computed as a comparison. The effects of temperature and incident direction of PKA are studied in detail. The results show that the temperature reduces the number of surviving Frenkel pairs (FPs), and the incident direction of PKA shows little correlation with them. Furthermore, the increasing temperature promotes the point defects to form clusters but reduces the number of defects due to the accelerated recombination of vacancies and interstitial atoms at relatively high temperature. The cluster fractions of interstitials and vacancies both increase with the PKA energy, whereas the increase of interstitial cluster is slightly larger due to their higher mobility. Compared to pure Ti, the presence of Al and V is beneficial to the formation of interstitial clusters and indirectly hinders the production of vacancy clusters.

• Journal of the Korean Institute of Navigation
• /
• v.14 no.4
• /
• pp.41-52
• /
• 1990

Due to the constantly varying sea-state with which any wave energy conversion device must contend in order to extract energy efficiently , the ability to control the device's position relative to the incident waves is critical in achieving the creation of a truly functional and economical wave energy device. In this paper, the authors will propose methodology based on the theory of a variable structure system to utilize a three dimensional source distribution as a model to estimate anticipated surge, sway and yaw of a wave energy conversion device relative to varying angles and characteristics of incident waves and there from derive a feedback to a sliding mode controller which would reposition the device so as to maximize its ability to extract energy from waves in constantly varying ocean conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.57-58
• /
• 2022

Pilots are always exposed to unpredictable risks of the marine environment because they are boarding the ship through pilot ladders or gangways at sea. Since the pilot plays an important role in securing the safety of ships entering or departing from the port, the injury of the pilot greatly affects the overall safety of the ship. The purpose of this study is to analyze pilot incidents and predict accidents. For this purpose, the pilot injury accident cases are analyzed and potential situations are identified through a survey. And the pilot injury accident was predicted. The results can be used as basic data for prevention of pilot-related accidents.