• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.125-128
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• 2003

This paper proposes efficient cloth animation and collision handling methods. There have been various techniques for the generation of cloth behavior. However, the cloth animation is still a challenging subject in real-time environments. This paper presents an efficient animation method based on implicit integration. The proposed method can efficiently animate virtual cloth object with complex geometry. In addition, this paper also introduces an efficient collision handling method. The collision resolution is another important issue in cloth animation since deformable objects has special collision problem called self-collision. In this paper, the self-collision was successfully avoided in real - time environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1033-1036
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• 2013

A study about collision resolution is needed because huge file, video and multimedia information are transmitted to wireless LAN. CSMA/CR protocol guarantees fairness, but doesn't consider QoS. To practicalize CSMA/CR protocol in saturation fully-connected single hop network environments, this paper proposes method of collision compensation. previous CSMA/CR protocol chooses CR Slot only considering fairness, but this paper chooses front CR Slot for compensation of collision to station experiencing collisions. The station transmits jam signal and has channel priority of transmission. So transmitting efficiency and successful transmission probability rise. This proposed simple method can offer benefit to station experiencing collisions without additional hardware cost.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1769-1775
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• 2004

In presence of collision between two rigid bodies, they exhibit impulsive behavior to generate physically feasible state. When the frictional impulse is involved, collision resolution can not be easily made based on a simple Newton's law or Poisson's law, mainly due to possible change of collision mode during collision, For example, sliding may change to sticking, and then sliding resumes. We first examine two conventional methods: the method of mode evolution by differential equation, and the other by linear complementarity programming. Then, we propose a new method for mode evolution by solving only algebraic equations defining mode changes. Further, our method attains the original nonlinear impulse cone constraint. The numerical simulation will elucidate the advantage of the proposed method as an alternative to conventional ones.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.690-693
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• 2004

This paper proposes a multi-resolution electrostatic potential field (MREPF) based solution to the mobile robot path planning and collision avoidance problem in 2D dynamic environment. The MREPF is an environment method in calculation time and updating field map. The large scale resolution map is added to EPF and this resolution map interacts with the small scale resolution map to find an optimal solution in real time. This approach can be interpreted with Atlantis model. The simulation studies show the efficiency of the proposed algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.33-44
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• 1999

This paper describes the Autonomous Vehicles (AV) which are operated for their own tasks. There are chances of conflict resolution such as sharing the same path which can lead to the risk of a collision. This research represents some ways of negotiating the conflict resolution by generating cooperative actions. Negotiation while traveling the path is accomplished by using priority and by announcing the start time of the task. When there is a risk of collision, the AV tries to dissolve the situation of conflict resolution by concurrently adjusting mutual speed and by performing the algorithm of passing. If the speed of the AV cannot be adjusted, it measures the distance between the counterpart of the AV and an obstacle along the path. Then it judges either to proceed by passing the counterpart of the AV or to turn back after observing the current circumstances. The performance of the algorithm described above was proven by a simulator.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.74-79
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• 2005

In this paper, we propose a novel approach to decentralized motion planning and conflict-resolution for multiple mobile agents working in an environment with unexpected moving obstacles. Our proposed motion planner has two characteristics. One is a real-time collision prognosis based on modified collision map. Collision map is a famous centralized motion planner with low computation load, and the collision prognosis hands over these characteristics. And the collision prognosis is based on current robots status, maximum robot speeds, maximum robot accelerations, and path information produced from off-line path planning procedure, so it is applicable to motion planner for multiple agents in a dynamic environment. The other characteristic is that motion controller architecture is based on potential field method, which is capable of integrating robot guidance to the goals with collision avoidance. For the architecture, we define virtual obstacles making delay time for collision avoidance from the real-time collision prognosis. Finally the results obtained from realistic simulation of a multi-robot environment with unknown moving obstacles demonstrate safety and efficiency of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2691-2707
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• 2014

Medium access control is critical in wireless networks for efficient spectrum utilization. In this paper, we introduce a novel collision resolution method based on the technique of known interference cancellation, and propose a new MAC protocol named as CR-MAC, in which AP tries to decode all the collided data packets by combining partial retransmissions and known interference cancellation. As the collided transmissions are fully utilized, less retransmission is required, especially in a crowded network. The NS-2simulation and MATLAB numerical results show that, under various network settings, CR-MAC performs much better than the IEEE 802.11 DCF in terms of the aggregation throughput and the expected packet delay.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.179-182
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• 2005

The Home Phoneline Networking Alliance (HomePNA) 2.0 technology can establish a home network using existing in-home phone lines, which provides a channel rate of 4 - 32 Mbps. HomePNA 2.0 Medium Access Control (MAC) protocol adopts an IEEE 802.3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method, a Quality of Service (QoS) algorithm, and a Distributed Fair Priority Queuing (DFPQ) collision resolution algorithm. In this paper, we analyze the HomePNA 2.0 MAC protocol and propose the architecture of HomePNA 2.0 MAC controller circuit. Then, we present the simulation result of each block included in the HomePNA 2.0 MAC controller.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.2
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• pp.37-43
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• 2007

Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.155.4-155
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• 2001

This paper deals with the inertia property-based redundancy resolution in posture control of a mobile manipulator. As a measure for the redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method that can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation ...