• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.46-55
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• 2009

In RFID field, when the neighboring readers try to occupy the same or adjacent channel simultaneously, there exists reader-to-reader interference; it calls reader collision. From the reader collision, the tags cannot response correctly query from the reader. Reader anti-collision schemes have been developed, and particularly, the Listen-Before-Talk(LBT) scheme is proposed to avoid reader collision in ETSI in multi channel environment. However, in ETSI, there is a drawback that the reader collision does not decreases effectively because the reader selects randomly a channel without considering the channel environment and readers try to occupy the channel concurrently. In this paper, we propose a algorithm based on LBT scheme considering multi channel environment as well as made up for the drawbacks of LBT The proposed algorithm applies random backoff, the collision avoidance mechanism. And it can reduce delay because of our proposed estimation mechanism Simulation using OPNET shows that the proposed algorithm achieves higher superiority than that of the simple algorithms in sparse and dense reader mode.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.825-830
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• 2009

Pharmaceutical compounds enter the water environment through the diverse pathways. Because their concentration in the water environment was frequently detected in the level of ppt to ppb, the monitoring system should be optimized as much as possible for finding appropriate management policies and technical solutions. One Factor At a Time (OFAT) approach approximating the response with a single variable has been preferred for the optimization of LC-MS/MS operational conditions. However, it is common that variables in analytical instruments are interdependent. Therefore, the best condition could be found by using the statistical optimization method changing multiple variables at a time. In this research, response surface analysis (RSA) was applied to the LC-MS/MS analysis of emerging antibiotic compound, sulfamethoxazole, for the best sensitivity. In the screening test, fragmentation energy and collision voltage were selected as independent variables. They were changed simultaneously for the statistical optimization and a polynomial equation was fit to the data set. The correlation coefficient, $R^2$ valuerepresented 0.9947 and the error between the predicted and observed value showed only 3.41% at the random condition, fragmentation energy of 60 and collision voltage of 17 eV. Therefore, it was concluded that the model derived by RSA successfully predict the response. The optimal conditions identified by the model were fragmentation energy of 116.6 and collision voltage of 10.9 eV. This RSA can be extensively utilized for optimizing conditions of solid-phase extraction and liquid chromatography.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1602-1606
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• 2008

In the Rail Safety Regulations article 16, deceleration rate in the survival spaces should be limited as far as is practicable to 5g, and shall not be more than 7.5g. As it is impractical to evaluate complete train behaviour by testing, the achievement of the objectives shall be validated by dynamic simulations corresponding to the reference collisions scenarios. But initial design and evaluation procedure, impact dynamics model which classified 1D and 2D is more useful than full scale model. This paper presents acceleration response characteristics between 1D and 2D dynamics model under head-on collision in standard collision scenarios.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.236-243
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• 2013

Offshore wind turbines has to be proved against accidental events such as ship collision. In this study, ship collision fragility analysis of offshore wind turbine is done. Dynamic collision analysis is accomplished by considering soil foundation interaction and fluid structure interaction. Uncertainties due to ship weight and speed, angle are also considered. By analyzing dynamic response of offshore wind turbine, fragility curves are obtained for different damage levels. They can be used for restricting boat speed around the wind turbine and allowable size of the boat for inspection and for other purposes. Results of the fragility, it was confirmed fragility of collision speed of bulk ship of 30,000DWT and 850ton barge ship.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.81-87
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• 2010

This study presents the results of collision and lift analyses of a cylinders-connected protector under stock anchor colliding and dragging. For the analyses, the terminal velocity of the stock anchor was obtained first, and, then, the velocity was used to calculate the falling distance of the stock anchor in air. In addition, two other falling distances were considered for purposes of comparison. From the finite element analyses, using ANSYS, the maximum responses obtained from the stock anchor colliding and dragging were obtained and compared for different collision distances (3, 5, and 8.83 m) and dragging angles (0, 30, 60, $90^{\circ}$). Then, the maximum displacements and stresses were discussed, along with the strength and dimensions of the protector. Finally, conclusions were made for the maximum responses.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.234-240
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• 2016

We propose a novel framework for markerless camera-based games. By using a visual camera, our method may yield robust human body segmentation with high performance comparable to the segmentation using depth cameras. The edges of human bodies are detected by subtracting gradient backgrounds, and human body regions are segmented by the operations based on mathematical morphology. Collisions between detected regions and virtual objects are determined by finding the colliding time using intra-frame positions of virtual objects. Experimental results show that the proposed method may produce robust segmentation of human bodies, thereby and the collision responses are more accurate than previous methods. Therefore, the proposed framework can be widely used in camera-based games requiring high performance.

• 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.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.168-175
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• 1996

Except the collision avoidance performance related to the rapid lane change, the 4WS vehicle has better dynamic stability and handling performance than the conventional 2WS vehicle which has close relation with the driver's safety, a 4WS conrol method with the effect of steering wheel angular velocity is proposed based on the fact that the driver steers abruptly the steering wheel to avoid the collision. And the effects of the proposed 4WS control method are investigated on the dynamic stability and handling performance by using the ISO lane change test code.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.109-116
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• 2004

This paper describes a cloth simulation system for dressing 3D virtual human model with different pieces of clothing. The garments are constructed of cutting patterns seamed together. The system reads a body file and a cutting pattern file and produces a new model dressed with the specified garment by using a physical simulation based on a mass-spring model. For the realistic cloth simulation, it performs collision detection and response between triangles of the 3D human model and the garment. Because the number of triangles of a human model is very large. the collision detection and response requires a lot of time. To overcome this problem, we propose a pruning method which decreases the number of collision detection and response by a space-subdivision method. Experimental results show that the system produces realistic images and makes it possible to sew a garment around a virtual human body in several seconds.