• The Journal of Korea Robotics Society
• /
• v.15 no.3
• /
• pp.277-285
• /
• 2020

A differential drive wheeled robot is a kind of mobile robot suitable for indoor navigation. Model predictive control is an optimal control technique with various advantages and can achieve excellent performance. One of the main advantages of model predictive control is that it can easily handle constraints. Therefore, it deals with realistic constraints of the mobile robot and achieves admirable performance for trajectory tracking. In addition, the intention of the robot can be properly realized by adjusting the weight of the cost function component. This control technique is applied to the local planner of the navigation component so that the mobile robot can operate in real environment. Using the Robot Operating System (ROS), which has transcendent advantages in robot development, we have ensured that the algorithm works in the simulation and real experiment.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.4
• /
• pp.65-71
• /
• 2020

In order to accurately track the trajectory of the smartphone indoors and outdoors, the WiFi Fingerprint method and the Pedestrian Dead Reckoning method are fused. The former can estimate the absolute position, but an error occurs randomly from the actual position, and the latter continuously estimates the position, but there are accumulated errors as it moves. In this paper, the model and Kalman Filter equation to fuse the estimated position data of the two methods were established, and optimal system parameters were derived. According to covariance value of the system noise and measurement noise the estimation accuracy is analyzed. Using the measured data and simulation, it was confirmed that the improved performance was obtained by complementing the two methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.62-65
• /
• 2018

This paper comes out with the study on sensing data collection strategy in a Software-Defined Mobile Edge vehicular networking. The two cooperative data dissemination are Direct Vehicular cloud mode and edge cell trajectory prediction decision mode. In direct vehicular cloud, the vehicle observe its neighboring vehicles and sets up vehicular cloud for cooperative sensing data collection, the data collection output can be transmitted from vehicles participating in the cooperative sensing data collection computation to the vehicle on which the sensing data collection request originate through V2V communication. The vehicle on which computation originate will reassemble the computation out-put and send to the closest RSU. The SDMEVN (Software Defined Mobile Edge Vehicular Network) Controller determines how much effort the sensing data collection request requires and calculates the number of RSUs required to support coverage of one RSU to the other. We set up a simulation scenario based on realistic traffic and communication features and demonstrate the scalability of the proposed solution.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.5
• /
• pp.405-411
• /
• 2011

This paper presents a hierarchical trajectory planning method which can handle a collision-free of the planned path in complex and dynamic environments. A PV (Path & Velocity profile) planning method minimizes a sharp change of orientation and waiting time to avoid a collision with moving obstacle through detour path. The path generation problem is solved by three steps. In the first step, a smooth global path is generated using $A^*$ algorithm. The second step sets up the velocity profile for the optimization problem considering the maximum velocity and acceleration. In the third step, the velocity profile for obtaining the shortest path is optimized using the fuzzy and genetic algorithm. To show the validity and effectiveness of the proposed method, realistic simulations are performed.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.6
• /
• pp.20-26
• /
• 2003

This study proposes the construction of attractor quadrant method for high-precision cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to Perform cutting Processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics and attractor quadrant characteristics. In quantitative quadrant feature extraction, 1,309 point in the case of A17075 (one quadrant) and 1,406 point (one quadrant) in the case of brass were proposed on the basis of attractor reconstruction. Proposed attractor quadrant method can be used for high-precision cutting characteristics evaluation of non-ferrous metals.

• Journal of the Korea Society for Simulation
• /
• v.27 no.1
• /
• pp.39-49
• /
• 2018

An SLBM (submarine-launched ballistic missile) seriously threatens the national security due to its stealthiness that makes it difficult to detect in advance. We consider a destroyer deployment optimization problem for effectively detecting an SLBM. An optimization model is based on the two-person zero-sum game in which an adversary determines the firing and arriving places with an appropriate trajectory that provides a low detection probability, and we establish a destroyer deployment plan that guarantees the possibly highest detection probability. The proposed two-person zero-sum game model can be solved with the corresponding linear programming model, and we perform computational studies with a randomly generated area and scenario and show the optimal mixed strategies for both the players in the game.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.11
• /
• pp.902-910
• /
• 2018

This paper deals with spacecraft intercept problem on non-coplanar elliptical obit considering J2 perturbation. This disturbance addressed in this work is a major factor changing the trajectory of a spacecraft orbiting the Earth. To resolve this issue, a real-time intercept method is proposed. This method is based on the optimization problem which consist of the equation of motion considering spherical earth and impulse, and the optimal solution numerically obtained is set as the direction of the thrust of the interceptor. The position error is resolved by iteratively solving the optimization problem and modifying the direction of thrust of interceptor. The proposed method in this paper is verified by using various numerical examples.

• Journal of radiological science and technology
• /
• v.44 no.1
• /
• pp.31-37
• /
• 2021

This study aim of quantitative assessment of Noise Power Spectrum(NPS) and image characteristics of by acquired the optimal image for noise characteristics and quality assurance by using magnetic resonance imaging(MRI). MRI device was (MAGNETOM Vida 3.0T MRI; Siemense healthcare system; Germany) used and the head/neck shim MR receive coil were 20 channels coil and a diameter 200 mm hemisphere phantom. Frequency signal could be acquired the K-space trajectory image and white image for NPS. The T2 image highest quantitatively value for NPS finding of showed the best value of 0.026 based on the T2 frequency of 1.0 mm-1. The NPS acquired of showed that the T1 CE turbo image was 0.077, the T1 CE Conca2 turbo image was 0.056, T1 turbo image was 0.061, and the T1 Conca2 turbo image was 0.066. The assessment of NPS image characteristics of this study were to that could be used efficiently of the MRI and to present the quantitative evaluation methods and image noise characteristics of 3.0T MRI.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.6
• /
• pp.137-145
• /
• 2016

A novel tracking method is proposed to find coronary artery using high-order curve model in coronary CTA(Computed Tomography Angiography). The proposed method quickly generates numerous artificial trajectories represented by high-order curves, and each trajectory has its own cost. The only high-ranked trajectories, located in the target structure, are selected depending on their costs, and then an optimal curve as the centerline will be found. After tracking, each optimal curve segment is connected, where optimal curve segments share the same point, to a single curve and it is a piecewise smooth curve. We demonstrated the high-order curve is a proper model for classification of coronary artery. The experimental results on public data set sho that the proposed method is comparable at both accuracy and running time to the state-of-the-art methods.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.6
• /
• pp.90-101
• /
• 2016

This study was initiated to develop an algorithm for traffic condition adaptive optimal traffic signal control for isolated intersections based on the vehicle trajectory data. The algorithm determines the optimal cycle length, phase lengths, phase sequences using the data collected under V2X communication environment every second. In addition, the algorithm utilizes a traditional feature of the actuated signal control, gap-out, using traditional detector systems to consider the mixture of normal vehicles and vehicles equipped with the V2X communication function. The performance of the algorithm was compared with that of the fixed signal timing plan which was optimized with Synchro under a microscopic traffic simulation-based test bed. As a result, the overall performance, including average delay, average stop delay, the number of stops, and average speed, are improved apparently. In addition, the amount of improvement get bigger as the traffic volume in the intersection as well as the number of vehicles equipped with the V2X communication function increase.