• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.311-315
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• 2007

This paper proposes a revised query tree algorithm in RFID systems. The proposed QT_ecfi algorithm revises the QT algorithm, which has a memory-less property. In the QT_ecfi algorithm, the tag will send the remaining bits of their identification codes when the query string matches the first bits of their identification codes. When the reader receives all the responses of the tags, it knows which bit is collided. If the collision occurs in the last bit, the reader can identify two tags simultaneously without further query. While the tags are sending their identification codes, if the reader detects a collision bit, it will send a signal to the tags to stop sending. According to the simulation results, the QT_ecfi algorithm outperforms the QT algorithm in terms of the number of queries and the number of response bits.

• BMB Reports
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• v.30 no.4
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• pp.253-257
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• 1997

Negative ion fast atom bombardment (FAB) mass spectra were found to allow the determination of the linkage positions in a series of underivatized linkage-isomeric oligosaccharides. A previous work (Laine et al., 1988) reported that ion patterns of linkage-isomeric trisaccharides could be distinguished by a positive ion. Negative ion FAB collison-activated dissociation (CAD) mass spectrometry (MS) spectra of trisaccharides exhibited better sensitivity than the positive ion mode and provided specific fragmentation patterns according to the linkage positions. Especially, the fragmentations, m/z 205 in F6 and m/z 221 in G6, not occuring in 1-3 or 1-4 linkage. were an indication of 1-6 linkage, by changing collision energies from + 10 eV to +60 eV. The survival ratios of molecular ions in each collision energy set gave support to previous results in which the order of bond stability was 1-6>1-4>1-3 linkage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.1-8
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• 1999

During the last 10 years, the various type of high speed craft have been greatly developed, and since around of 1990 the large size of high speed passenger and/or cargo vessels are also introduced and took into the service in the various routes over the world. In a marine traffic way some bridge need to build across a rivers, cannals or a waterways. This one will be an obstruction and potential risk of collision in the way of high speed craft. Accordingly some of collision accident have been reported, which were caused by a lost control, wind and hydrodynamic forces, fog or human errors. In this paper a high speed craft having 40 m length is assumed to be collided with a circular type of bridge piers at right angle. The mode of deformation, penetration depth of collapse, impact forces, reduction of speed, loss of kinetic energy, and influence of scantlings, etc. have been calculated in each speed with a time variation to find a maximum values within a limit, and are graphically presented.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.772-779
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• 2008

Through this study, standard design guidelines for the high speed EMU have been derived to meet the crashworthiness requirements of the Korean rollingstock safety regulation. The crashworthiness regulation requires some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 kph, and a collision against a standard deformable obstacle of 15 ton at 110 kph. The complete train set will be composed of 2TC-6M with 13 ton axle load, different from KTX with the power car of 17 ton axle load. Using theoretical and numerical analyses, some crashworthy design guidelines were derived in terms of mean crush forces and energy absorptions for main crushable structures and devices. The derived design guidelines were evaluated and improved using one dimensional spring-mass dynamic simulations. It is shown from the simulation results that the suggested design guidelines can easily satisfy the domestic crashworthiness requirements.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.646-651
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• 2004

Crashworthy design of a train is a systematic approach to ensure the safety of passengers and crews in railway transportation for the prescribed accident scenarios. This approach needs new structural arrangements and designs to absorb higher levels of impact energy in a controlled manner and interior designs to minimize passenger injuries. In this paper, crashworthy design approach is applied to the tilting train express (TIX) design which is newly being developed. Based on a head-on collision and a level crossing collision scenarios, the crash behaviors of a TTX design candidate arc evaluated numerically using the finite element method. Finally, design alternatives which show better crashworthy performances are proposed and verified through the full-rake collision simulations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.71-78
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was peformed. The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used. The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.2
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• pp.181-191
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• 2002

Spray calculation has been studied to understand the behavior of the spray in a combustion chamber But the spray dispersion has not been predicted properly in a high velocity injection spray or a wall impaction spray. In this study the extended grazing collision model is applied to improve the problem. The gas phase is modelled by the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. The droplet distributions, penetration, width and gas flows are compared for the cases with or without extended model. The extended collision model makes the results better.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.38-46
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• 2002

This paper evaluates crashworthiness of KHST carbodies under the SNCF accident scenario (collision against a movable rigid mass of 15 tons at 110 kph) and the scenario of train-to-train collision at 30 kph. The numerical results show that the final design of the KHST power-car doesn't have a good response on crashworthiness. So an improved design has been suggested for it. The improved design has shown good performances in the viewpoint of energy absorption and survival space at several numerical simulations, such as the accident collided against a deformable dump truck of 15 tons at 110 kph, the driver's dummy analysis, and the accident of train-to-train collision for the first three units at 30 kph.

• Bulletin of the Korean Chemical Society
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• v.16 no.2
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• pp.101-104
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• 1995

In an attempt to understand the nature of hyperthermal ion-surface collisions, noble gas ion beams (He+, Ne+, Ar+, and Xe+) are scattered from a Si(100) surface for collision energies of 20-300 eV and for 45°incidence angle. The scattered ions are mass-analyzed using a quadrupole mass spectrometer and their kinetic energy is measured in a time-of-flight mode. The scattering event for He+ and Ne+ can be approximated as a sequence of quasi-binary collisions with individual Si atoms for high collision energies (Ei > 100 eV), but it becomes of a many-body nature for lower energies, Ar+ and Xe+ ions undergo mutliple large impact parameter collisions with the surface atoms. The effective mass of a surface that these heavy ions experience during the collision increases drastically for low beam energies.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.358-363
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• 2008

Through this study, 2D multibody dynamics models for analysis of train collisions have been developed to evaluate the crashworthiness requirements of the TSI regulation. The crashworthiness regulation requires some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 kph, and a collision against a standard deformable obstacle of 15 ton at 110 kph. The complete train set will be composed of hybrid model with 2D and 1D model. Using numerical analysis of the hybrid model, some crashworthy design were evaluated in terms of mean crush forces and energy absorptions for main crushable structures and devices. especially, 2D model can evaluate overriding effect in train collisions. It is shown from the simulation results that the suggested hybrid model can easily evaluate the crashworthiness requirements.