• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.157-164
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• 2015

The present study is to identify discharge characteristic from the mouth of floating debris in the Nakdong River through real time tracking of moving route and by analyzing hydrometeorologic environmental. To identify the path and route of outflow through the mouth of the river of floating debris, small-sized buoy equipped with satellite location transmitters was used. Moreover, to identify hydrometeorologic environmental, flux of the river, change of discharge of the River-Mouth Weir and wind direction of the mouth of the river area were analyzed. From now on, the present study is expected to be utilized as basic data to identify damage and flowing into nearby ocean of the floating debris of Nakdong River in time of severe rain storm.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.429-436
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• 2008

Nowadays fires must be detected rapidly Abstract, and by connecting the detector's distribution, sender, transponder, receiver and others can be connected. Mechanical systems are implemented in today's buildings. However, this kind of constructing method has some disadvantages, that is, if fire happens somewhere, we cannot judge where the fires happen, and it is also difficult to judge what extent the fires reach. In order to overcome the disadvantages, in this paper, according to the tendency of combining the Ubiquitous and Intelligent Network, we propose a type of system by using the method of comparing the differences of the existed systems. The proposed system is designed to perceive the fires rapidly and confirm the fire place and fire scale correctly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.10
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• pp.1982-1990
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• 1994

We implemented a PLDRO(Phase Locked Dielectric Resonator Oscillator) using the concept of the feedback property of PLL(Phase Locked Loop) for Ku-band(10.95-11.70 GHz). The conventional approaches to a PLDRO design use varactor diode tuning method.. But in theis paper, the PLDRO has the advantage of the frequency sensitivity to changes in the supple voltage of the oscillating device without the frequency-variable part by varactor diode voltage-control. and uses a SPD(Sampling Phase Detector) for phase-comparision. The PLDRO is composed of the DRO phase-locked to the reference signal of UHF band by using a SPD for high frequency stability and can be available for European FSS(Fixed Satellite Service) at 10.00GHz. The PLDRO generates the output power of 8.67 dBm at 10.00 GHz and has a phase noise of -81 dBc/Hz at 10 kHz offset from carrier. The hamonic and spurious characteristics have -42.33 dBc and -65dBc respectively. This PLDRO has much better frequency stability, lower phase noise, and more economical effect for a satellite system than conventional DRO.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.595-601
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• 2006

This study presents an ultrasonic location awareness system for the ubiquitous computing with absolute position. The flight time of ultrasonic waves is determined by a period detecting technique which is able to extend the sensing range compared with traditional methods. For location awareness, ultrasonic waves are sent successively from each ultrasonic transmitter and synchronized by radio frequency (RF) signal, where the transmitting part is fixed and the receiving part is movable. To expand the recognizing range, cell matching technique and coded ultrasonic technique are introduced. The experimentation for various distances is accomplished to verify the used period detecting technique of U-SAT system. The positioning accuracy by using cell matching is also verified by finding the locations of settled points and the usability of coded ultrasonic technique is verified. As a result, the possibility of ultrasonic location awareness system for the ubiquitous computing can be discussed as a pseudo-satellite system with low cost, a high update rate, and relatively high precision, in the places where GPS is not available.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.253-257
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• 2006

The objectives of this paper are to estimate home range and core habitat area of wild bores in Jirisan National Park of Korea. A radio-telemetry study was carried out on 5 wild boar individuals (3 females and 2 males). Except one individual whose enough data could not be collected, the mean home range size of 4 individuals was $5.13km^2$ (95% kernel) and mean core habitat area was $1.18{\pm}0.31km^2$ (50% kernel). Home-range sizes of 2 females were $6.21km^2\;and\;5.45km^2$ each, and that of 2 males were $5.15km^2\;and\;3.72km^2$ each, which means home-ranges of female boars were larger than those of male boars in this research. This result is presumed to have been caused by the fact that the males were sub adult individuals weighing 40 kg and 19 kg when they were captured for this research.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.203-211
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• 2015

The implanted telemetry system provides the monitoring of species while they move within their cages. Species monitored include mice, rats, rabbits, dogs, pigs, primates, sheep, horses, cattle, and others. A miniature transmitter implanted in each animal measures one or more parameters. Parameters measured include arterial pressure, intra-pleural pressure, left ventricular pressure, intra-ocular pressure, bladder pressure, ECG, EMG, EEG, EOG, temperature, activity, and other parameters and transmits the data via radio frequency signals to a nearby receiver. Every conventional dedicated transmitter contains one or more sensors, cpu and battery. Due to the expected life of battery, the measuring time is limited. To overcome these problems, electromagnetic inductive coupling based wireless power transmission technology using multiple transmit coils were proposed. Each coil having different active area are driven by the coil driver. In this research, parallel resonance based coil driver was proposed. In addition, the device to detect where the receiver is positioned was proposed. From the experiments we show how to determine the driving condition of coil driver.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.4
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• pp.111-119
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• 2012

Time Stretched Pulse (TSP) is used for transmitting and analyzing the impulse signal over the designated spatial place. However, if transfer functions of transmitter and receiver are unknown, performance investigation of free field in temporal domain is barely possible due to the overlap between the direct and indirect signal from the space. Generally, the free field or hemi-free field is evaluated by the Annex A of ISO 3745 in which utilizing the inverse square law with one-third octave band signals. In this paper, the author performs analysis of free field via applying TSP with inverse square law and the results are compared with the one-third octave band signals. According to the analysis of deviation between the corresponding signal and inverse square law model, the proposed TSP method provides the comparable performance index to the one-third octave band signal with reduced measuring time. Provided that the pre-whitening can be implementable by employing the speaker and microphone transfer function, further analyses from TSP compression are able to be performed such as multipath separation from time domain data. The anechoic chamber used in this experiment is verified conformance with ISO 3745 for free field and hemi-free field condition for limited frequency of the signal.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.249-255
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• 2015

In this paper, we present an azimuth error analysis for the correlative interferometer direction finding. The correlative interferometer is a direction finding method that compares the theoretical and measured phase differences. The direction of the radio transmitter can be estimated by obtaining the maximum correlation between two data sets. We used a 5-element circular array antennas arranged in a circle. To derive the correlation function between antenna elements, we assume that the incident plane wave arrives from a certain angle and the phase difference of each antenna can be derived by comparing with the reference. The suggested direction finding gives a relatively accurate result even if the radio transmitter is located in the higher altitude.

• Journal of Navigation and Port Research
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• v.26 no.2
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• pp.221-226
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• 2002

To provide reliable data for drift prediction models, field experiments were carried out in the coastal region off Busan port. Four different size of vessels(10, 30, 50, 90G/T ton) were deployed for the experiment. Among them G/T 50ton class vessel was equipped with instruments measuring the currents, winds, headings and trajectory data. In the rest of vessels only the position data were recorded for the purpose of target divergence study. The trajectories of each vessel were measured by DGPS(Differential Global Positioning System) and collected by APRS(Automatic Position Reporting System). The experiment was done in wind of 2~10m/s and current of 0.5~1.5m/s. The leeway was derived by subtracting surface current velocity from target drifting velocity. The leeway rate of G/T 50ton vessel was found to be about 3.6% and the computed leeway speed equation was $U_L$=0.042 W - 0.034. The processed leeway angle data were deflected by $-30^{\circ}$~$40^{\circ}$ from the direction of ship drift.

• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.1-9
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• 2014

This study was to understand the ecological characteristics of the goral through the study on goral behavioral characteristics and to be carried out to provide basic behavioral data such as annual home range, seasonal home range and monthly used altitude with 4,752 locations obtained during the study period through home range analysis of three long-tailed gorals (Naemorhedus caudatus) in Soeraksan. For this study, gorals who were rescued from heavy snow in Seoraksan were used. The gorals were equipped with GPS Collar, released at their natural habitats, and then monitored from May, 2010 to September, 2011. According to our results, annual home ranges of the gorals (n=3) have $0.88km^2$ of MCP 95%, $0.27km^2$ of MCP 50%, $0.43km^2$ of FK 95%, and $0.09km^2$ of FK 50% respectively. Seasonal home range of MCP 95% was $0.47km^2$ in spring, $0.45km^2$ in summer, $0.63km^2$ in fall and $0.50km^2$ in winter respectively and home ranges of fall was the largest. In the case of FK 95% analysis, home ranges were $0.23km^2$ in spring, $0.19km^2$ in summer, $0.33km^2$ in fall, and $0.22km^2$ in winter respectively and the largest seasonal home range was fall. Female and male annual home ranges of the gorals were $1.03km^2$ for female and $0.58km^2$ for male. In analysis of the monthly used altitudes which were used Jun, July, and August were higher than in the other months and the altitudes which were used in Dec, Jan, and Feb were lower than in the other months. This study was to secure basic data for the habitat management policy, restoration, and conservation of Korea gorals and to be conducted to contribute to the success in doing or planning stage of the wild animal restoration.