• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.103-113
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• 2011

This research is to select a path planning algorithm to maximize survivability for Unmanned Aerial Vehicle(UAV). An UAV is a powered pilotless aircraft, which is controlled remotely or autonomously. UAVs are currently employed in many military missions(surveillance, reconnaissance, communication relay, targeting, strike etc.) and a number of civilian applications(communication service, broadcast service, traffic control support, monitoring, measurement etc.). In this research, a mathematical programming model is suggested by using MRPP(Most Reliable Path Problem) and verified by using ILOG CPLEX. A path planning algorithm for UAV is selected by comparing of SPP(Shortest Path Problem) algorithms which transfer MRPP into SPP.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.314-317
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• 2003

In this paper, a measurement and analysis program is developed, that can be utilized to measure and analyze radio propagation characteristics. This program is able to control the measurement instruments including spectrum analyzer through a GPIB interface, and analyze the measured data to yield mean excess delay and RMS delay spread. The measured path loss can be compared with theoretical path loss in free space or inside tunnels. The measured and analyzed results can also be presented in the forms of graphs. As those tasks can be conducted on the measurement spot, this program is very helpful for performing and verifying measurements.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.969-970
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• 2008

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.12
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• pp.547-552
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• 2002

In this paper, the path loss in domestic terrain environments for IMT-2000 are measured and considered. Domestic terrain environments are classified and received power is measured at 1.9201GHz. In addition, the Path loss is calculated with consideration of the radiation pattern of antennas based on the results of measurement. For the consideration of path loss in domestic terrain environments, each path loss are fitted with the same slope of a reference model as "COST-231 HATA Urban Model", and then both are compared. As a result, all of the path loss in domestic terrain environments are lower than the path loss of a reference model as "COST-231 HATA Urban Model". We found that a difference of path loss in domestic terrain environments and a reference model is 5dB in urban, 8dB in sparse urban, 12dll in dense suburban, 13dB in suburban, 19dB in sparse suburban, and 29dB in road.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.10
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• pp.993-998
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• 2007

To verify the 2D or 3D positioning accuracy of a multi-axes stage is not easy, particularly, in the case the moving path of the stage is not linear. This paper is a study on a measuring method for the curved path accurately. A machine vision technique is used to trace the moving path of two-axes stage. To improve the accuracy of machine vision, a zoom lens is used for the 2D micro moving path. The accuracy of this method depends of the CCD resolution and array align accuracy with the zoom lens system. Also, a further study for software algorithm is required to increase the tracing speed. This technique will be useful to trace a small object in the 2D micro path in real-time accurately.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2311-2318
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• 2005

Progress in the LCD industries has been very rapid. Therefore, their manufacturing lines require larger LCD glass-handling robots and more precise path control of the robots. In this paper, we present two practical advanced algorithms for high-precision path generation of an LCD glass-handling robot. One is high-precision path interpolation for continuous motion, which connects several single motions and is a reliable solution for a short robot cycle time. We demonstrate that the proposed algorithm can reduce path error by approximately 91% compared with existing algorithms without increasing cycle time. The second is real-time static deflection compensation, which can optimally compensate the static deflection of the handling robot without any additional sensors, measurement instruments or mechanical axes. This reduces vertical path error to approximately 60% of the existing system error. All of these algorithms have been commercialized and applied to a seventh-generation LCD glass-handling robot.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.7
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• pp.455-461
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• 2015

The paper deals with the accuracy comparison between two kinds of ultrasonic paths for flow rate measurement. In the Z-path, two transducers are installed on the opposite sides of each other on a pipe, and the ultrasonic waves generated at one transducer propagate to arrive at the other one only by refraction. In the V-path, two transducers are installed on one side of a pipe, and the ultrasonic waves reflected at the inner wall of the pipe are received. Transit times were confirmed to identify the propagation paths by comparing the theoretically calculated results and measured ones. The flow rate measurements with two kinds of ultrasonic paths appeared very similar. It would be possible to select either of the paths by considering the advantages and disadvantages.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.1
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• pp.35-44
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• 2014

Sound pressure levels in the receiving room while testing airborne sound insulation performance are varied by the measuring points. This may increase the measurement error, then decrease the measurement reliability. With this reason the research has carried out on the method to reduce deviations of sound pressure level in the ISO type rectangular laboratory focusing on the measurement of airborne sound insulation performance. Tests were made to see the effect of sound absorption in the receiving room, loudspeaker locations, microphones locations and flanking transmission path. Consequently, it was resulted that sound absorption in the receiving room and the loudspeaker location have influence on the sound level deviations especially in the low frequency. The microphone location was very important to get measurement reliability. The effective measuring point, which the sound level difference with average sound pressure level is within 2 dB, could yield most reliable average sound pressure level. Therefore it is necessary to find the effective measuring points in the receiving room. Flanking transmission path should be sealed using sound absorber or magnet etc. to prevent from lowering the sound insulation performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.400-410
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• 2008

Reduction of structure-borne noise in the compartment of a car is an important task in automotive engineering. Many methods which analyze noise transfer path have been generally used for structure-borne noise. These methods are useful in solving particular problem but do not quantify the effectiveness of vibration isolation for each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow measurement has been used for a simple isolation system or a laboratory based isolation system. This paper identifies the transfer path of booming noise in a SUV. The powertrain used for test has a in-line 4cylinder engine and 5-shift auto-transmission. This powertrain is transversely supported by four isolators. We calculated the energy flow throughout four isolator by the measurement of power flow and the contribution of energy flow at each isolator.