• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.122-130
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• 2010

This paper presents an active ranging system based on laser structured-light image. The structured-light image processing is computationally efficient in comparison with the conventional stereo image processing, since the burdensome correspondence problem is avoidable. In order to achieve robustness against environmental illumination noise, an efficient image processing algorithm, i.e., integration of difference images with structured-light modulation is proposed. Distance equation from the measured structured light pixel distance and system parameter calibration are addressed in this paper. Experiments and analysis are carried out to verify performance of the proposed ranging system.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.133-139
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• 2003

Position and trajectory data in-flight rocket are important informations to determine flight safety of rocket. In general tracking system, radar and transponder are used to acquire position information. Rocket position and trajectory can be determined by RF communication between ground station and in-flight rocket, and antenna position date. In this paper, it explains the ranging system which is low resolution rather than radar system but system configuration is simple. Therefore this system is useful for experimental flight vehicle.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.16-22
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• 2009

This paper aims at designing an impulse-radio ultra-wideband (IR-UWB) transceiver, especially targeting the IEEE 802.15.4a indoor ranging and communication systems. We first investigate the IEEE 802.15.4a IR-UWB signals and suggest the full-digital transceiver architecture accordingly. Since the wireless systems equipped with the impulse signal have the property of low-duty cycle, i.e., discontinuity in time, while the conventional systems takes the continuous signals, it is required to reconfigure the system design, including link budget. Following brief introduction to our IEEE 802.15.4a IR-UWB system hardware, we finally examine the ranging performance in indoor environments to verify our system design.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.12
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• pp.1103-1111
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• 2016

Korea Astronomy and Space Science Institute (KASI) has been operating SLR (Satellite Laser Ranging) system with 2kHz repetition rate for satellite precise orbit and spin determination as well as space geodesy. But the SLR system was improved to be capable of laser ranging with high repetition rate, up to 10kHz by developing new operation software and novel range gate generator, called HSLR-10. The HSLR-10 will contribute to the accurate spin rate determination of geodetic satellites and geodetic research due to its largest repetition rate in the world. In this study, the development methodology and configuration of operation software are addressed, and its validation results are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1128-1135
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• 2010

A wireless positioning system using ultra-wideband (UWB) for indoor wireless positioning uses ranging data in order to accurately estimate location. Commonly, ranging uses time of arrival (TOA), time difference of arrival (TDOA) based on arrival time. The most fundamental issue in the ranging for wireless positioning is to obtain clock synchronization among the sensor nodes and to correct an error caused by the relative clock offset from each node. In this paper, we propose ranging and positioning technique using common clock in order to solve both clock synchronization and clock offset problems. To verify the performance of proposed, we simulated ranging and positioning in channel model introduced by IEEE 802.15.4a Task Group and then results show that location estimation is unaffected by clock offset.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9C
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• pp.778-785
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• 2010

This paper proposes a high-precision ranging scheme based on channel estimation technique and multipath delay analysis in IR-UWB systems. When the IR-UWB signal is transmitted and received, the high-precision ranging is estimated with the time-of-arrival information of the signal. In the proposed scheme, the channel estimation process with the minimum mean square error technique or zero forcing technique is performed and the overlapped multipath within the pulse is analyzed with matrix pencil (MP) algorithm to achieve the ranging accuracy of centimeters. The performance of proposed scheme is evaluated with various IEEE 802.15.4a channel models and the relationship between the ranging performance and the computational complexity is analyzed in terms of the MP parameter values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.159-166
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• 2008

In this paper, we proposed an algorithm to solve the problem that can't maintain hop synchronization using only early-late gate tracking loop due to the drift of geo-stationary satellite in frequency hopping satellite communication system. When the signal is transferred to downlink through DRT(Dehop-Rebop Transponder), the problem with synchronization loss is occurred periodically when using only early-late gate tracking loop, because of energy loss in each side portion of hop due to orbital variation of the satellite. To solve this problem, we have developed Anti-Shrink synchronization tracking algorithm which uses the prediction value of transmission timing and the structure of inner-outer gate instead of early-late gate with the ranging information. Through simulations, we showed that the performance of the Anti-Shrink algorithm is better than that of simple inner-outer energy ratio algorithm and similar to that of conventional early-late tracking loop algorithm with ranging information. No synchronization failure in the proposed algorithm was occurred because of less energy loss and robustness without the ranging information.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7A
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• pp.540-547
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• 2009

In this paper, we work for the efficient use of the initial ranging contention slot in OFDMA based wireless mobile networks. Specially, the collision reduction method using an automatic adaptive optimal algorithm is studied for initial ranging contention slot used at initial connection of the mobile terminals. As a result, we propose the algorithm that achieves the collision minimization and the auto-dynamic slot arrangement of the initial ranging slots. To evaluate the proposed algorithm, we compare the simulation results of IEEE802.16e fixed initial ranging slot allocation method versus the proposed algorithm. The simulator is developed based on the IEEE802.16e standard MAC frame structure and processing procedures. As the simulation results, we can expect the proposed algorithm can be applied for the unmanned coastal base station because the proposed algorithm has the effect of minimizing administration cost for the base station.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.17-25
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• 2000

ATM PON system is regarded as a solution of the next generation access network because it can cover various types of subscribers in a single platform. In this paper, we describe the merit of the ATM PON and the key protocols for its operation. Above all, the ranging is the most important protocol providing a mean of the time-division multiple access in the system. A problem in the protocol is that the window size, the time interval that ranging cell arrives, is too long. During the interval, user traffics cannot be send to the upstream, which makes the quality of service degraded. In this paper, we suggest a method to minimize the window size when the length of the optic fiber is known with some deviation. The window size can be reduced as 7 % of the conventional method when the deviation of the length is 1 Km.

• Journal of the Korean Society of Food Culture
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• v.11 no.3
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• pp.339-348
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• 1996

Physicochemical and sensory characteristics of Korean traditional alcoholic beverages, such as Kwahaju, Sokokju, Baikhaju, Samhaeju and Hosanchun were investigated during fermentation with the difference of input step and treatment of rice and Nuruk (Korean-style bran koji). pH values in all treatments were similar to be ranged $3.1{\sim}3.2$, but acidity of the treatment brewed without seed mash was $1.5{\sim}2$ times higher than that of the treatment brewed with seed mash. The concentration of alcohol in all treatments increased as the concentration of the Nuruk increased. The alcohol concentrations of Samhaeju and Hosanchun ranging from 6.5% to 7.7% were higher than those of Kwahaju, Sokokju and Baikhaju ranging from 7.9% to 10.6%. Residual reducing sugar contents of Kwahaju, Sokokju and Baikhaju ranging from 4.6 g/L to 9.7 g/L were lower than those of Samhaeju and Hosanchun ranging from 14.2 g/L to 15.5 g/L. The consumed total sugar contents of Kwahaju, Sokokju and Baikhaju ranging from 125.4 g/L to 159.2 g/L were higher than those of Samhaeju and Hosanchun ranging from 111.2 g/L to 123.8 g/L, and the treatments brewed with seed mash showed more sugar consumption than the treatments brewed without seed mash. Sensory quality in the treatments brewed with seed mash was better than those of without seed mash. Concentration of Nuruk and preparation of seed mash from it were critical factors compared to input step and treatment of rice in Korean traditional alcoholic beverage brewing.