• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.69-75
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• 2024

This paper proposes an IoT-based indoor autonomous driving system that applies SLAM (Simultaneous Localization And Mapping) and Navigation techniques in a ROS (Robot Operating System) environment based on TurtleBot3. The proposed autonomous driving system can be applied to indoor autonomous wheelchairs and robots. In this study, the operation was verified by applying it to an indoor self-driving wheelchair. The proposed autonomous driving system provides two functions. First, indoor environment information is collected and stored, which allows the wheelchair to recognize obstacles. By performing navigation using the map created through this, the rider can move to the desired location through autonomous driving of the wheelchair. Second, it provides the ability to track and move a specific logo through image recognition using OpenCV. Through this, information services can be received from guides wearing uniforms with the organization's unique logo. The proposed system is expected to provide convenience to passengers by improving mobility, safety, and usability over existing wheelchairs.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.6
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• pp.505-510
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• 2016

This paper presents a searching method of corresponding points robust to rotational error for scan-matching used for SLAM(Simultaneous Localization and Mapping) in mobile robot. A differential driving mechanism is one of the most popular type for mobile robot. For driving curved path, this type controls the velocities of each two wheels independently. This case increases a wheel slip of the mobile robot more than the case of straight path driving. And this is the reason of a drifting problem. To handle this problem and improves the performance of scan-matching, this paper proposes a searching method of corresponding points using extraction of a closest point based on rotational radius of the mobile robot. To verify the proposed method, the experiment was conducted using LRF(Laser Range Finder). Then the proposed method is compared with an existing method, which is an existing method based on euclidian closest point. The result of our study reflects that the proposed method can improve the performance of searching corresponding points.

• Journal of Korea Game Society
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• v.15 no.4
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• pp.169-178
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• 2015

Providing various levels of difficulty of game play is one of important considerations in game development. In this paper, we propose a method for obtaining the challenges that will be placed on the track of an one-player car driving game. Herein challenges denote obstacles on the track, and the level of difficulty is represented by an estimated time needed for driving one lap of the track. In the proposed method, the problem for finding challenge placement is modeled as an IP(Integer Programming) one, and then LP relaxation and Simultaneous Annealing are employed to find a solution. To the experiment with the proposed method, we can obtain challenge placements to approximately meet given target driving times. Also, after practically driving on the track where those obtained challenges are being placed, it is seen that the average driving times approximate the target driving times of those challenge placements. Our method can allow game play with various levels of difficulty so that the users' interest and the level of immerse are expected to be raised.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1380-1386
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• 2012

It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.359-362
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• 2003

The aerostatic stage. which is used in semiconductor process, is demanded higher velocity and more precise accuracy for higher productivity and integrated performance. So, in the case of XY stage, H type structure, which is designed two co-linear axis of guide-way, driving force in one surface, has advantage of velocity and accuracy compared to conventional tacked type XY stage. To analyze characteristics of H type aerostatic stage, H type aerostatic surface XY stage is made, which is driven by linear motor and detected position with precise optical linear scale. And, analyze characteristics of motion error, effect of angular motion on positioning accuracy error and effect of simultaneous control on variation of velocity.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.149-151
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• 2008

This paper presents an architecture for driving multiple parallel cold cathode fluorescent lamps (CCFLs) for back lighting applications. The key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1007-1009
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• 2008

This paper presents an architecture for driving multiple paralleled cold cathode fluorescent lamps (CCFLs) for back lighting applications. The key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition. This like the EEFL it will be able to use the CCFL is the thing. Also, it investigates the effect where the leakage current goes mad to the Lamp.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.126-128
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• 2008

This paper presents an architecture for driving multiple paralleled cold cathode fluorescent lamps (CCFLs) for back lighting applications. Multi CCFL operation and increase of brightness, the key to the architecture is a proposed capacitive coupling approach for lamp ignition. This system is consist of a flyback converter, a single inverter to drive multiple lamps and conductive floating reflector. The topology is capable of driving a number of parallel lamps with independent accurate lamp, The capacitive coupling the leakage inductance and stray capacitance creation which it used, current regulation and improving cost effectiveness with significant reduction in size and weight, compared to typical high frequency ac ballast. Experimental demonstration results for ten of parallel CCFLs with simultaneous ignition.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.62-72
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• 2010

PM OLED is used in many applications as one of the display for the next generation. The most essential problems are the power dissipation and the short life time in applying PM OLED into a commercial application. Many efforts are made in developing the panel and in improving the circuit for expanding the current market wider. The life time in PM OLED is expanded by lessening the power dissipation of the circuit for the magnitude of the driving current is lowered. It is possible to minimize the power dissipation from improving the driving technology. The classical technology, Row-to-Row driving, is that row is selected one by one while applying the column current input individually. The multi-line driving is a new technology which is to select multiple rows simultaneously while applying the column current as a whole. However, the solution of the multi-line driving is NP-complete problem. The efficiency is dependant on the sort of picture and the driving condition. This paper presents the new efficient multi-line driving which is that the multiple lines are selected by applying column current together after grouping the simultaneous driving group applying the gnew efficient muthe coi-line dr coefficient. Bengrouping the several rows which has the higher coi-line dr coefficient, the more efficient driving is realized to present the high quality image and to lessen the power dissipation and to stretch the life time in the PM OLED.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.783-790
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• 2013

Circular path generation for ball bar measurement using the simultaneous movement of two axes with at least one rotary axis requires the execution of CAM software. However, a change in the machine type or measurement condition requires a new execution of the CAM software, which is cumbersome. This paper presents a circular path generation technique that does not require CAM software and is applicable to different types of driving axes with an arbitrary structural configuration of machine tools and any ball bar setup condition. Mathematical equations are derived for three cases using the proposed technique. In addition, to inspect the measurement feasibility for avoiding physical interference among the ball bar parts, a tilting angle calculation is proposed. The validity of the proposed technique was verified by performing a ball bar experiment with A and C as the simultaneous axes of a five-axis machine tool.