• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.132-144
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• 2004

This paper presents a new method driving multiple robots to their goal position without collision. To consider the movement of the robots in a work area, we adopt the concept of avoidability measure. The avoidability measure figures the degree of how easily a robot can avoid other robots considering the velocity of the robots. To implement the concept to avoid collision among multiple robots, relative distance between the robots is proposed. The relative distance is a virtual distance between robots indicating the threat of collision between the robots. Based on the relative distance, the method calculates repulsive force against a robot from the other robots. Also, attractive force toward the goal position is calculated in terms of the relative distance. These repulsive force and attractive force are added to form the driving force for robot motion. The proposed method is simulated for several cases. The results show that the proposed method steers robots to open space anticipating the approach of other robots. In contrast, since the usual potential field method initiates avoidance motion later than the proposed method, it sometimes fails preventing collision or causes hasty motion to avoid other robots. The proposed method works as a local collision-free motion coordination method in conjunction with higher level of task planning and path planning method for multiple robots to do a collaborative job.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1756-1763
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• 2011

This paper was researched the straight cruise of fish robot according to biological mimic, and it was compared the proposed method which was considered up to 7th order components in fourier series of Liu's tail motion function with the approximate method which was used general sine function by simulation. If fish robot has a large number of links and if the length of tail link is long. The end rotary joint trajectory of tail motion function generally is different from sine function. Therefore The approximate method which expresses tail motion trajectories as fundamental component in fourier series has a problem. Through the computer simulation, the proposed method showed 10% excellent propulsion and velocity than the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1777-1781
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• 2011

Tosin backplane system design of this study (Backplane) from the HSTL (High-Speed Transceiver Logic) characteristics of the transmit and receive data using the HSPICE simulations and the actual implementation on the FPGA Data transmission characteristics were described by comparing the simulation results. Simulation and measurement criteria for point to point data transmission characteristics of wire length possible to send and receive data about the speed limits were reviewed. Measured point to point connection to send and receive signals at terminal velocity, the factors that affect the electrical noise around the wire length and showed a very important role.

• Journal of Mechanical Science and Technology
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• v.20 no.11
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• pp.1801-1812
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• 2006

In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, pushrod force as the end control parameter, and an antilock sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. Simulation results indicate that the velocity and spacing errors were slightly larger than the results that without considering wheel slip effect, the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and the limit for the antilock control on non-constant adhesion road condition was determined by the minimum of the equivalent adhesion coefficient.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.473-476
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• 2012

Energy is one of the most important resources for human society and the history of its development and use have been part of human life. Especially as the need of eco-friendly energy development has been on the rise, the interest in alternative energy has grown consistently. This paper, so as to identify the energy output and efficiency from a micro vertical-axis wind generator. by utilizing a smart phone, presents a system to analyze the production efficiency of real-time energy, according to the wind velocity and the width and the material of the blade of the climate change system in the Meteorological Office.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.729-731
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• 2013

The compensation characteristics of 40 Gbps optical signals depending on figure of merit (FOM) of dispersion compensating fiber with dispersion coefficient of -125 ps/nm/km are investigated in this research. Simulation results show that the more fiber span number and launch power increase, the more the effects of FOM of DCF on the compensated signals increase. However, it is also confirmed that the more the effects of optical nonlinearity increase, the more FOM decrease.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.655-658
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• 2012

Optimal net residual dispersion (NRD) and distribution pattern of (SMF) length and residual dispersion per span (RDPS) in optical transmission links with artificial distribution of SMF length and RDPS required to flexibly design of optical links in dispersion management (DM) technique for compensating the distorted 960 Gbps optical signals due to interaction of group velocoty dispersion (GVD) and optical nonlinear effects are induced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.638-641
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• 2012

Optimal net residual dispersion (NRD) and effective launching power range of optical transmission links with random distribution of single mode fiber (SMF) length and residual dispersion per span (RDPS) required to flexibly design of optical links in dispersion management (DM) technique for compensating the distorted 960 Gbps optical signals due to interaction of group velocoty dispersion (GVD) and optical nonlinear effects are induced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.285-288
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• 2007

A realization for automatic stock cubic measuring and distributing management embedded system with 3 dimensional ultrasonic sensing is presented in this paper. The height and width of cubic are measured by comparing the 3 values from 3 ultrasonic sensors with reference when an object is passing the conveyer and length is calculated by the passing time and velocity, compensate cubic values for error to vary with the environment temperature, and reduce the error by averaging the sensing data not to be right posture of object. The system enables to classify and load a packed stocks at the store and transportation practically based on the rectangular hexahedral objects.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.196-205
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• 2000

As the number of cars is suddenly increasing, the number of cars on road exceeds the capacity of the road. In order to disperse the stream of traffic, there are many approaches for calculating the degree of congestion using traffic monitoring camera, and analyzing the velocity or the number of moving objects. Since those methods use background image, it is necessary to prepare the proper background image. In this paper, we proposed the algorithm to calculate the degree of congestion without background image. We perform DCT to the road image to obtain the edge information of cars, and then use it for calculating the degree of congestion.