• International Journal of Aeronautical and Space Sciences
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• v.17 no.2
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• pp.232-239
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• 2016

Recently, in order to increase the efficiency and mission success rate of UAVs (Unmanned Aerial Vehicles), the necessity for formation flights is increased. In general, GPS (Global Positioning System) is used to obtain the relative position of leader with respect to follower in formation flight. However, it can't be utilized in environment where GPS jamming may occur or communication is impossible. Therefore, in this study, monocular vision is used for measuring relative position. General PC-based vision processing systems has larger size than embedded systems and is hard to install on small vehicles. Thus FPGA-based processing board is used to make our system small and compact. The processing system is divided into two blocks, PL(Programmable Logic) and PS(Processing system). PL is consisted of many parallel logic arrays and it can handle large amount of data fast, and it is designed in hardware-wise. PS is consisted of conventional processing unit like ARM processor in hardware-wise and sequential processing algorithm is installed on it. Consequentially HW/SW co-designed FPGA system is used for processing input images and measuring a relative 3D position of the leader, and this system showed RMSE accuracy of 0.42 cm ~ 0.51 cm.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.346-348
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• 2005

무선 통신망은 유선 통신망에 비하여 대역이 한정적이기 때문에 효율적인 대역의 이용은 매우 중요하다. 그러나 802.16 BWA 시스템의 UGS 알고리즘은 보낼 데이터가 없어도 일정한 간격으로 고정 대역을 단말에 계속 할당하기 때문에 대역의 낭비가 심하다. 본 논문에서는 VAd가 가능한 단말에서 UGS 알고리즘을 이용할 때, 보낼 패킷이 없는 경우에는 그 유휴 대역을 이용하여 우선순위가 낮은 nrtPS나, BE 알고리즘을 이용하는 패킷을 대신 전송하는 방법을 제시함으로써, 802.16 BWA 시스템에서 효율적인 상향링크 스케줄링을 구현한다.

• Journal of Korean Society for Quality Management
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• v.17 no.2
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• pp.121-141
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• 1989

This paper is concerned with a development and evaluation of heuristics for the multi-stage sequence dependent flowshop sequencing. Eighteen heuristics, CAM1, CAM2, and etc., are proposed. The performance measure is a makespan which is to be minimized. The experiment for each algorithm is designed for a 4*3*3 factorial design with 360 observations. The experimental factors are PS(ratio of processing times to setup times), M(number of machines), N(number of jobs). The makespan of the proposed heuristics is compared with the optimal makespan obtained by the complete enumeration of schedules. This yardstick of comparison is called a relative error. The mean relative errors of the eighteen heuristics are from 2.048% to 8.717%. The computational results are analysed using SPSS. The experimental results show that the three factors are statistically significant at 5% level. The simulation for the large size problems is conducted to show having the similar computational results like the small size problems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.58-66
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• 2002

Electric power facilities must have effective grounding to provide means to carry electric current into the earth under fault conditions and to prevent damage of equipment, ignition, and electrocution of personnel. This paper resent an algorithm called the Pattern Search method for the optimal parameters selection of the grounding system Simulation results using these parameters obtained from the PS method verify that the grounding systems are adequately designed.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.32-38
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• 2020

This paper describes a method for tracking attitude and position of underwater robots. Underwater work with underwater robots is subject to differences in work efficiency depending on the skill of the operator and the utilization of additional sensors. Therefore, this study developed an underwater robot that can operate autonomously and maintain a certain attitude when working underwater to reduce difference of work efficiency. The developed underwater robot uses 8 thrusters to control 6 degrees of freedom motion, IMU (Inertial Measurement Unit), DVL (Doppler Velocity Log) and PS (Pressure Sensor) to measure attitude and position. In addition, the thruster allocation algorithm was designed to follow the control desired value using 8 thrusters, and the motion control experiments were performed in the engineering water basin using the thruster allocation method.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.138-141
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• 2007

The permanent scatterer SAR interferometry (PSInSAR) technique has been developed more recently and has been applied to monitor slow but consistent ground subsidence. Since PSInSAR has the advantages in terms of baseline and temporal decorrelation, PSInSAR technique using X-band may also provide useful information about a ground deformation in detail. We developed our codes for a persistent scatterer analysis, and then apply to ERS-1/2 C-band data over Las Vegas in order to validate our new developed algorithm. Based on this test, PS technique using X-band observation such as TerraSAR-X or KOMSAT 5 will be developed.

• Journal of Korean Society for Quality Management
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• v.17 no.1
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• pp.35-47
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• 1989

This paper is concerned with a development and evaluation of heuristic algorithms for the n-job, M-stage flowshop with sequence dependent setup times. Three heuristic algorithms, CAIDAN, DANNEN and PETROV, are proposed. The makespan is taken as a performance measure for the algorithms. The experiment for each algorithm is designed for a $4{\times}3{\times}3$ factorial design with 360 observations. The experimental factors are PS (ratio of processing times to setup times), M (number of machines), and N (number of jobs). The makespan of the proposed heuristic algorithms is compared with the optimal makespan obtained by the complete enumeration method. The result of comparision of performance measure is called a relative error. The mean relative errors of CAIDAN, DANNEN and PETROV algorithms are 4.488%. 6.712% and 7.282%, respectively. The computational results are analysed using SPSS. The experimental results show that the three factors are statistically signiticant at 5% level.

• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1000-1004
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• 1997

In this paper the current-voltage characteristics of a submicron GaAs MESFET is simulated by using the self-consistent ensemble Monte Carlo method. The numerical algorithm employed in solving the two-dimensional Poisson equation is the successive over-relaxation(SOR) method. The total number of employed superparticles is about 1000 and the field adjusting time is 10fs. To obtain the steady-state results the simulation is performed for 10ps at each bias condition. The simulation results show the average electron velocity is modified by the gate voltage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.12 no.19
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• pp.39-47
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• 1989

This paper considers a multi-stage flowshop scheduling Problem where the setup times of jots depend on immediately preceding jobs. Three heuristics algorithms, CAMPBELL, PEIDAN and CAMRING are proposed. The performance measure is a minimization of makespan. The parameters of simulation model are PS(ratio of the processing times to setup times), M(number of machines), and N(number of job). This simulation model for each algorithm is a 4$\times$3$\times$3 factorial design with 360 observations. The makespan of the proposed heuristic algorithms is compared with the optimal makespan obtained by the complete enumeration of schedules. This yardstick of comparison is defined as a relative error. The mean relative error of CAMPBELL, PEIDAN, and CAMRING algorithms are 4.353%, 7.908%, and 8.578% respectively. The SPSS, is used to analyse emphirical results. The experimental results show that the three factors are statistically significant at 5% level.

• Journal of applied mathematics & informatics
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• v.42 no.2
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• pp.223-235
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• 2024

In this paper, our primary focus revolves around the examination of a set of fractional stochastic models. Through our investigation, we can establish the presence of a solution and its distinctiveness. Additionally, we employ a moment-based algorithm to estimate the coefficients within these models and provide evidence that these estimations maintain their asymptotic characteristics. To support this claim, we conduct experimental studies using simulations and numerical examples.