• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.25-33
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• 2010

Collision between vessels may lead to structural damage and penetration of hulls. The structural damage of a hull may eventually bring about global collapse of the hull girder and outflow of oil, which would contaminate seawater. Therefore, various regulations require the strength of a vessel after collision to satisfy given criteria, and owners usually request collision analyses to confirm the structural safety of their vessels. In the process of designing a vessel to satisfy the collision strength criteria, the strength has been assessed mostly by conducting collision analyses using numerical techniques, such as dynamic, non-linear, finite-element analysis. Design is an inherently iterative process during which many changes are necessary due to the endless needs for reinforcement and modification. Numerical techniques are not adequate for coping with a situation in which collision analysis is frequently required to provide the revised results that reflect the repetitive changes in designs. Numerical techniques require a lot of time and money to conduct in spite of recent improvements in computing power and in the productivity of modeling tools. Therefore, in this paper, an analytical technique is introduced and a collision problem is idealized and simplified using reasonable assumptions based on appropriate background. The technique was applied to an example of an actual FPSO and verified by comparing the results with results from the numerical technique. A good correlation was apparent between the results of the analytical and numerical techniques.

• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.187-192
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• 2006

We reviewed the collision event with pc-based shooting games and existing collision detection algorithms. Then we proposed a new collision check technique using a small quadrilateral unit. by which existing quadrilateral collision detection techniques can be made up for. For demonstration we implemented a simple shooting game having its screen output. We proved that the proposed technique can be applied to real computer games by means of showing the experimental results and screen outputs from implemented real games.

• KSCI Review
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• v.14 no.1
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• pp.249-254
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• 2006

In this paper, I review the collision processing algorithm using existing quadrilateral unit and present problems with it. Then I propose a collision check technique of a small quadrilateral unit, by which the defects with simple quadrilateral collision has been made up for. I finally show that the proposed algorithm can be applied to real games in terms of presenting the experiment results and screen design for implemented real games.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.166-173
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• 2007

Collision analysis problems between ship to ship can be generally classified into the external mechanics(outer dynamics) and internal mechanics(inner dynamics). The former can be also dealt with the concept of fluid-structure interaction and the use of rigid body dynamic program, depending on the ways handling the hydrodynamic pressure due to surrounding water. In this study, full scale ship collision simulation was carried out, such as a DWT 75,000 ton striking ship collided at right angle to the middle of a DWT 150,000 struck ship with 10 knots velocity, coupling MCOL, a rigid body mechanics program for modeling the dynamics of ships, to hydrocode LS-DYNA. It could be confirmed that more suitable damage estimation would be performed in the case of the collision simulations with consideration of surrounding water through the comparison with the collision simulation results of fixed struck ships without it. Through this study, the opportunity could be obtained to establish a more effective ship collision simulation technique between ship to ship.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.112-119
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• 2011

This paper introduces a technique for calculating the degree of collision risk used in collision avoidance system of AUVs. The collision risk will be reckoned with the fuzzy inference, which uses TCPA(Time of the Closest Point of Approach) and DCPA(Distance of the Closest Point of Approach) as factors. A method to obtain TCPA and DCPA for 3-dimension is suggested. The degree of collision risk is provided to collision avoidance system, and is verified the effectiveness through simulation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.9-15
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• 2014

It is not easy to analyze the behavior of a structural body composed of particles such as rocks using the finite element method facilitating typical element meshes because we cannot ignore the interactions among particles. In the study, we investigated the applicability of smooth particle hydrodynamics (SPH) element method for collision analysis of rock-berm by comparison with the conventional Lagrange method. As the result, SPH technique is expected to be capable of realistic simulation under collision analysis of material composed of particles.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.30-31
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• 2009

Through the full scale ship collision response analysis of high speed passenger ship with underwater floating matters, the objective of this study is to perform the crashworthy safety assessment of its hull and passengers. For this safety assessment, diverse collision scenarios could be established through the thorough understanding of damage mechanisms due to the collision of its hydrofoil system with underwater floating matter examining the damage informations of its hull and passengers from the collision accidents, and through the estimation of the damages of its hull and passenger. The next step, crashworthy safety assessment of its hull and passengers, was carried out by the collision response analyses of high speed passenger ship with underwater floating matter using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code in consideration of surrounding water, and using local zooming analysis technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.33-43
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• 2013

This paper proposes a distributed MAC protocol called Carrier Sensing Multiple Access with Collision Resolution (CSMA/CR) considering fully-connected single hop network environments for next-generation wireless LAN with high density of stations. The proposed CSMA/CR is compatible with the conventional MAC protocols by observing the operation of CSMA/CA and is able to detect a collision promptly without RTS/CTS exchange by applying the technique of CSMA/CD to wireless environments. Moreover, once a collision is detected, the dedicated resource is allocated to the next transmission and so the collision that may occur again is resolved. We investigate some implementation issues for the practicality of CSMA/CR and compare it with the typical distributed MAC protocols. The simulation results show that the proposed CSMA/CR has a low overhead as detecting a collision without the RTS/CTS exploitation and achieves always the best throughput regardless of the number of access stations, by using the reservation-based collision resolution technique.

• Journal of Internet Computing and Services
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• v.12 no.5
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• pp.101-111
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• 2011

Most researches in WSN-based parking management system used wireless sensors to monitor the events in a car parking area. However, the problem of car collisions in car parks was not discussed by previous researches. The car position details over time are vital in analyzing a collision event. This paper proposes a collision verification method to detect and to analyze the collision event in the parking area, and then notifies car owners. The detection uses the information from motion sensors for comprehensive details of position and direction of a moving car, and the verification processes an object tracking technique with a fast OBB intersection test. The performance tests show that the location technique is more accurate with additional sensors and the OBB collision test is faster compared to a normal OBB intersection test.

• Journal of Astronomy and Space Sciences
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• v.21 no.3
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• pp.209-220
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• 2004

Some methods have been presented to get optimal formation trajectories in the step of configuration or reconfiguration, which subject to constraints of collision avoidance and final configuration. In this study, a method for optimal formation trajectory-planning is introduced in view of fuel/time minimization using parameter optimization technique which has not been applied to optimal trajectory-planning for satellite formation flying. New constraints of nonlinear equality are derived for final configuration and constraints of nonlinear inequality are used for collision avoidance. The final configuration constraints are that three or more satellites should be placed in an equilateral polygon of the circular horizontal plane orbit. Several examples are given to get optimal trajectories based on the parameter optimization problem which subjects to constraints of collision avoidance and final configuration. They show that the introduced method for trajectory-planning is well suited to trajectory design problems of formation flying missions.