• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2163-2170
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• 2012

A signal receiving system can measure and analyze frequency, pulse modulation, scan modulation, frequency modulation on pulse, phase modulation on pulse of RF signal. A signal receiving system should be verified under simulated RF signal environment prior to verification on operation in fields. This paper describes an effective method to generate simulated RF signals with considering operational scenario. The simulated RF signal generator can be effectively used to evaluate the performance of the signal receiver and reduce the test cost of the signal receiver.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.353-356
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• 2011

A Signal Receiving system to collect and analyze RF signals should be verified under simulated RF signal environment prior to verification on operation in fields and tested by using simulated RF signals in order to estimate its electrical performance. Generally, typical Signal Receiving system can measure, analyze frequency, pulse modulation, scan modulation, phase modulation on pulse, frequency modulation on pulse etc on RF signals. These RF signals should be generated from simulated RF sources in laboratory. Also the simultaneous RF signals should be simulated on laboratory. This paper describes the results of studying effective simulated RF signal source generation, the methods of the precise RF test signal generation in consideration of operational scenario.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1638-1644
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• 2005

This paper suggests fur the study on a fluid velocity measuring system using ultrasonic transducer. In general, the time difference method to measure the distance between transducers has been known. In this paper, the practical technology for manufacturing ultrasonic flow meter system is studied using the time difference method. The ultrasonic transducer was designed and manufactured. The transmission and receiving algorithm for ultrasonic signal was studied. The ultrasonic flow measuring system was experimented in laboratory using a water reservoir for verifying the distance measuring accuracy. Finally, it was tested in flow calibration laboratory for the velocity measuring performance. The system, designed in this study, showed 0.3 mm resolution in distance measurement. For precise flow measurement, a high speed triggering algorithm is required for ultrasonic signal receiving.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1272-1277
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• 2004

GPS type portable-alarm-system is composed of satellite receiving equipment, signal transmission equipment, etc. Time errors occur because of the processing methods of the satellite receiving equipment and signal generator, the positional error of GPS itself, etc. With the recent rise of train speed, it becomes very important to secure the stability of portable-alarm-system from time errors, The present study estimated errors caused by the structure of portable-alarm-system, GPS errors. etc., and verified them. In addition, it examined the effects of such errors on portable-alarm-system according to train speed.

• Journal of the Korean Dietetic Association
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• v.12 no.3
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• pp.264-276
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• 2006

The purpose of this study was to propose HACCP system implementation properly and to secure the food safety of school foodservices in Pohang city since the proper facilities and equipment should be key factors in food safety and production. So this study was designed to evaluate existing equipment in food production area, receiving and dining area, and employee facilities. Questionnaire was mailed to 107 school foodservice dietitians in Pohang area and 97 were responded (90.7% response rate). Approximately sixty percent of foodservices were not available separate receiving or polluted area, fifty one percent were installed screen door for insecticidal and temperature and humidity control, and these environmental conditions were hard to keep kitchen dry and sanitary condition. Usually public schools were better equipped than private schools. Forty three percent of school foodservice had initial use of non-foodservice, opened before 1994, and thirty three percent of elementary school foodservice. Among employee facilities, hand washing sanitation stand was prepared seventy nine percent (78.9%) of school foodservices. Dietitians chose outworn equipment and facilities (30.9%), difficulties of maintaining standard temperature and humidity for foodservice (20.6%), lacking separate receiving or polluted area (13.4%), indirect contamination of water hoss (10.3%), and lacking employee facilities (10.3%) as critical points to correct in school foodservice. Therefore governmental regulating agencies must review and approval of plans prior to new construction or extensive remodeling of school foodservice facilities. In addition to these requirement, plan must be set-up step by step to implement HACCP system properly.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.48-55
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• 2021

The 3-coil magnetic resonance wireless power transmission system was analyzed using an equivalent circuit model, and the |S21| of the system was expressed as the equation of the Q of the three coils, the coupling coefficient k between the transmitting coil and the relay coil, the relay coil and the receiving coil. It is suggested that the maximum efficiency can be obtained when the relay coil is located in the center of the transmitting and the receiving coil. When the distance between the transmitting and the receiving coil is 30 cm and the two coils are aligned, maximum efficiency of 9 % is obtained with the relay coil centered between the coils. If the transmitting coil and the receiving coil are misaligned during a wireless charging of an electric vehicle, the efficiency is expected to decrease significantly compared to the aligned case. It is expected that the efficiency can be increased by using a relay coil and by rotating the coil.

• 한국해양학회지
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• v.30 no.1
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• pp.27-38
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• 1995

For the study of oceanic surface current, this work presents a system design which is composed of three parts, a Global Positiong System(GPS) unit, a transmitter with radio frequency (RF) modem and an antenna which are housed in a plastic spherical buoy, and computerised of VHF receiving system. The key idea for this study is to employ a commercially available GPS on a drifting buoy and to utilize the receiver position information from the buoy in determining the Lagrangian motion of surface ocean waters. Great efforts has been paid to the system design which would demand several points in harsh conditions common in the sea surface, that is power supply problems housed inside of a plastic buoy, optimizing transmitting radio frequency which limits transmitting distance to a receiving station. for all these difficulties, the system appears to be promising in future oceanic applications and is considered to economical compared to ARGOS drift buoy which is being used by commercial base. We believe that the system needs to be improved in terms of several aspects such as a longer transmitting distance, a power supply and software. for the test experiments in situ, the system has employed off the coast of Ku Ryong Po int the southeast part of Korea and successfully collected the surface current data. The results are presented for two cases from 21 to 31, March 1994 and 21 to 25, June 1994 in terms of current statistics and trajectories of drifting buoys.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.156-159
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• 2001

Recently, side scan sonar system has been developed and operated to survey cable laying, sunken bodies, geometry of sea bottom and so on. It uses the acoustic signals, which are emitted from two transducer arrays, left and right sides, to get geometric information of the specified area. This system consists of transceiver board, towed body, deck unit and GPS receiver. The transceiver board, nested in a watertight canister, controls the transmitting and receiving of the acoustic pulses from transducer arrays. After receiving the scattered signals, it processes BP(Band Pass) filtering, AGC(Automatic Gain Control), TVG(Time Varying Gain) and Heterodyne. The deck init has the signal processing part, A/D converter, power supplier, and real-time monitoring part. The towed body has been designed to satisfy the optimal hydrodynamic behavior during towing, In this paper, brief introductions on the design theory of transceiving part and some results from the field which have been operated recently will be introduced.

• Journal of the Korean Society for Nondestructive Testing
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• v.11 no.2
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• pp.15-21
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• 1991

A wireless acoustic emission (AE) system has been developed for continuous monitoring of rotating structures such as turbine rotors. The cable between preamplifier and signal processing unit of a conventional AE system was replaced by the frequency modulated telemetry. The detected signals were modulated and transmitted as an RF signals by the transmitting module, then received and demodulated by the receiving module. The distance between the transmitting and the receiving antennas could be separated up to 10cm within a reasonable signal-to-noise ratio. The simulated AE signals generated by pencil lead breaks from rotating structures were successfully detected using the developed wireless AE monitoring system.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.40-47
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• 1998

This paper presents the physiological signal processing CMOS one chip for transmitting human bodys small electrical signals such as electrocardiogram(EKG) or electromyogram(EMG) and the external system for receiving signals was implemented by the commercial ICs. For simultaneous four-subject four-channel telemetry, a new enfored synchronization techniqeu using infrared bi-directional communication has been proposed. The telemeter IC with the size of 5.1*5.1mm$^{2}$ has the following functions: receiving of command signal, initialization of internal state of all functional blocks, decoding of subject-selection signal, time multiplexing of 4-channel modulated physiological signals, transmitting of telemetry signal to external system and auto power down control. The newly designed synchronized oscillator with low supply voltage dependence in the telemeter IC operates at a supply voltage from 4.6~6.0V and the nonlinearity error of PIM modulator was less than 1.2%F.S(full scale). The power saving block operates at the period of 2.5ms even if the telemetry IC does not receive command signal from external system for a constant time.