• Proceedings of the KSRS Conference
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• v.1
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• pp.417-420
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• 2006

In these days, mobile application dealing with information contents on mobile or handheld devices such as mobile communicator, PDA or WAP device face the most important industrial needs. The motivation of this study is the design and implementation of mobile application using high resolution satellite imagery, large-sized image data set. Although major advantages of mobile devices are portability and mobility to users, limited system resources such as small-sized memory, slow CPU, low power and small screen size are the main obstacles to developers who should handle a large volume of geo-based 3D model. Related to this, the previous works have been concentrated on GIS-based location awareness services on mobile; however, the mobile 3D terrain model, which aims at this study, with the source data of DEM (Digital Elevation Model) and high resolution satellite imagery is not considered yet, in the other mobile systems. The main functions of 3D graphic processing or pixel pipeline in this prototype are implemented with OpenGL|ES (Embedded System) standard API (Application Programming Interface) released by Khronos group. In the developing stage, experiments to investigate optimal operation environment and good performance are carried out: TIN-based vertex generation with regular elevation data, image tiling, and image-vertex texturing, text processing of Unicode type and ASCII type.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1054-1059
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• 2005

The artificial potential method uses a potential field to guide a robot from a start to a goal configuration respectively. The potential field consists of attractive potential used to pull a robot toward a goal and repulsive potential to keep it away from obstacles. However, there are two problems concerning local minimum and computational cost to be resolved in conventional artificial potential methods. This study proposes a method utilizing a spline surface that interpolates arbitrary boundaries and a domain reduction method that reduces the unnecessary area. The proposed spline surface interpolates arbitrary shaped boundaries and is used as an artificial potential to guide a robot for global motion planning of a mobile robot. A reduced domain process reduces the unnecessary domain. We apply a distance-weighted function as such a function, which blends distances from each boundary with a reduction in computational time compared with other analytical methods. As a result, this paper shows that an arbitrary boundary spline surface provides global planning and a domain reduction method reduces local minimum with quick operation.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.1-6
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• 2012

In this paper, we present an obstacle avoidance control algorithm for mobile robots based on SFLC (single-input fuzzy logic controller) with an efficient fuzzy logic look-up table to replace the traditional complicated operation. This method achieves better performance than traditional methods in terms of efficiency. The output of a SFLC leads the robot to the target automatically although many obstacles on the path. Our experiments show that the robot has good performance in the view of path tracking and other efficiency.

• Korean Medical Education Review
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• v.13 no.2
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• pp.47-57
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• 2011

Purpose: This study was conducted to explore the current usage of high integration mannequin human patient simulators (hereafter HPS) in nursing education. Methods: Thirty-two faculty members in 11 nursing schools participated in this survey. the questionnaire consisted of some multiple-choice questions and open questions to collect data on the experience of faculty members with using HPS as well as quantitative information. Results: The faculty members who used HPS in their classes recognized the need to use simulation in nursing education. They identified the advantages of simulation education as promoting adaptation to the clinical environment(46.9%), promoting self-confidence(28.1%), promoting critical thinking(28.15), and making direct nursing skill practice available(28.1%). However, they considered the obstacles to the use of simulation in nursing education to be insufficient manpower(62.5%), insufficient time(40.6%), and difficulty in preparing a teaching strategy(34.4%). Conclusion: HPS is useful in nursing education, but systematic plans and policies regarding on its operation are needed to confirm its effectiveness. The results of this study generally provide a basic information for use of HPS in nursing education.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.377-384
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• 2006

In this paper the detection time of the distress signal for the satellite-based search and rescue (SAR) system is evaluated. Present LEOSAR system in operation employs a few Low-altitude Earth Orbit (LEO) satellites and hence provides poor and local coverage availability. This results in a considerably long waiting time for a distress beacon to be detected by a rescue mission control center. One can expect that the detection time of the distress signal will be significantly reduced if the proposed MEOSAR system, which is based on the Medium-altitude Earth Orbit (MEO) satellites, is implemented. Taking into account the influence of the obstacles on the beacon signal, simulations are carried out to evaluate the detection time of distress signals for the LEOSAR and MEOSAR systems and the corresponding results are analyzed.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.352-362
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• 2014

In this paper, a fuzzy logic controller is designed for a DC motor which can be used for navigation control of mobile robots. These mobile robots can be used for agricultural, defense and assorted social applications. The robots used in these fields can reduce manpower, save human life and can be operated using remote control from a distant place. The developed fuzzy logic controller is used to control navigation speed and steering angle according to the desired reference position. Differential drive is used to control the steering angle and the speed of the robot. Two DC motors are connected with the rear wheels of the robot. They are controlled by a fuzzy logic controller to offer accurate steering angle and the driving speed of the robot. Its location is monitored using GPS (Global Positioning System) on a real time basis. IR sensors in the robot detect obstacles around the robot. The designed fuzzy logic controller has been implemented in a robot, which depicts that the robot could avoid obstacle as well as perform its operation efficiently with remote online control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.917-921
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• 2013

This paper have analyzed the change of breakdown voltage for conduction path of double gate(DG) MOSFET. The low breakdown voltage among the short channel effects of DGMOSFET have become obstacles of device operation. The analytical solution of Poisson's equation have been used to analyze the breakdown voltage, and Gaussian function been used as carrier distribution to analyze closely for experimental results. The change of breakdown voltages for conduction path have been analyzed for device parameters such as channel length, channel thickness, gate oxide thickness and doping concentration. Since this potential model has been verified in the previous papers, we have used this model to analyze the breakdown voltage. Resultly, we know the breakdown voltage is greatly influenced on the change of conduction path for device parameters of DGMOSFET.

• Journal of Biosystems Engineering
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• v.25 no.2
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• pp.131-140
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• 2000

Spraying operation is one of the most essential in an orchard management and it is also hazardous to human body. for automatic and unmanned spraying , an autonomous travelling vehicle is demanded. In this study, a telemeter was developed using infrared beam which could detect trunks and obstacles measure distance and direction from the vehicle travelling in the orchard. The telemeter system was composed of two infrared LED transmitters and receivers, a beam scanning device for continuous object detection , two rotary encoders for angle detector, and a beam level controller for uneven soil surface. The detected distance and direction signal s were sent to personal computer which made for the system display the angular and distance measurements through I/O board. According to a field test in an apple farm, the system detected up to 10m distance under 12 V of transmitted beam intensity, however, it was recommended that the proper beam transmit intensity be 7 v at the 10 m distance, because of the negative effect to human body at 12 V. The error rate of this system was 0.92 % when the actual distance was compared to measured one. The system was feasible at the small error rate. The developed telemeter system was an important part for autonomous travelling vehicle provided the real time object recognition . A direction control system could be constructed suing the system. It is expected that the system could greatly contribute to the development of autonomous farm vehicle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.547-548
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• 2006

This study focuses on a determination of amount of Pt in the Pt/C for catalysts of polymer electrolyte membrane fuel cells (PEMFC). PEMFC offer low weight and high power density and being considered fur automotive and stationary power applications. The PEMFC behavior is quite complex is influenced by several factors, including catalysts and structure of electrode and membrane type. Catalyst of electrode is important factor for PEMFC. One of the obstacles preventing polymer electrolyte membrane fuel cells from commercialization is the high cost of noble metals to be used as catalyst, such as platinum. To effectively use these metals, they have to be will dispersed to small particles on conductive carbon supports. The optimal amount of Pt in Pt/C was investigated by using polarization curves in single cell with $H_2/O_2$ operation.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.60-69
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• 2010

Lookup-Table (LUT) based fuzzy controller for obstacle avoidance enhances operations faster in multiple obstacles environment. An LUT based fuzzy controller with Positive/Negative (P/N) fuzzy rule base consisting of 18 rules was introduced in our paper$^1$ and this paper shows a 50-rule P/N fuzzy controller for enhancing performance in obstacle avoidance. As a rule, the more rules are necessary, the more buffers are required. This paper suggests LUT sharing method in order to reduce LUT buffer size without significant degradation of performance. The LUT sharing method makes buffer size independent of the whole fuzzy system's complexity. Simulation using MSRDS(MicroSoft Robotics Developer Studio) evaluates the proposed method, and in order to investigate its performance, experiments are carried out to Pioneer P3-DX in the LabVIEW environment. The simulation and experiments show little difference between the fully valued LUT-based method and the LUT sharing method in operation times. On the other hand, LUT sharing method reduced its buffer size by about 95% of full valued LUT-based design.