• Spatial Information Research
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• v.18 no.4
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• pp.33-41
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• 2010

Approximately 100 permanent GPS stations are currently operational in Korea. However, only 10 sites have their own weather sensors connected directly to the GPS receiver. Thus. calculation of meteorological data through interpolation of AWS data are needed to determine precipitable water vapors at a specific GPS station without a meteorological sensor. This study analyzed the accuracy of two meteorological data interpolation methods called reverse sea level correction and kriging. As a result, the root-mean square-error of reverse sea level correction were seven times more accurate in pressure and twice more accurate in temperature than the kriging method. For the analysis of PWV accuracy, we calculated GPS PWV during the summer season in :2008 by using GPS observation data and interpolated meteorological data by reverse sea level correction. And, we compared GPS PWV s based on interpolated meteorological data with those from radiosonde observations and GPS PWV s based on onsite GPS meteorological sensor measurements. As a result, the accuracy of GPS PWV s from our interpolated meteorological data was within the required operational accuracy of 3mm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.19-26
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• 2008

We propose a selective detection scheme based on pulse repetition considering the BER (Bit Error Rate) performance and complexity of coherent IR-UWB (Impulse Radio-Ultra Wide Band) systems. To take system complexity into account, the proposed scheme transmits the UWB signals by pulse repetition at the transmitter, like conventional PRC (Pulse Repetition Coding). However, to effectively improve BER performance of the system, the proposed scheme performs selective detection by estimating the SNR (Signal-to-Noise Ratio) of the received pulse-repeated signal at the UWB receiver. Hence, the proposed scheme effectively improves BER performance of the coherent IR-UWB systems without increasing system complexity, as compared to the conventional PRC algorithm.

• Clean Technology
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• v.12 no.3
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• pp.138-144
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• 2006

Conversion of methane to synthesis gas in a capacitive rf plasma at low pressure was experimentally studied. In this plasma, electrons which had sufficient energy-level collided with the molecules of methane or oxygen-containing gas, which were than activated and converted to synthesis gas. The effect of input power, various oxygen-containing gas and composition of the gas mixture were investigated. The conversion of methane reached up to 100%. In all cases, hydrogen and carbon oxide were produced as primary products, and other compounds was generated. The conversion of methane and the yield of hydrogen and carbon oxides were increased with increasing the input power. Depending on the oxygen-containing gases, the composition of synthesis gas was varied.

• Journal of Korean Society of Transportation
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• v.22 no.3 s.74
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• pp.137-144
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• 2004

The real-time traffic information is considered to be the system to alleviate traffic congestion. An effective traffic information will help drivers make efficient travel decision, and network performance will be improved. To make efficient strategy of providing information, the analyst should quantify reduced congestion by the media traffic informations. Many other route diversion models considered only media-informations as information sources and ignored the impact of on-site informations such as visible delays and average speeds, which affect drivers' route diversion decision in practice. In those models, the effect of on-site informations could be treated to be the effect of media informations, and the effects of media informations would be over-estimated. The proposed model including the impact of on-site information can estimate the effect of media-informations. The results are expected to be applied to the analysis of traffic management policy such as ITS.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.245-250
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• 2019

We investigated the post-annealing effect of Sn-incorporated β-Ga₂O₃ (β-Ga₂O₃ : Sn) nanowires (NWs) grown on sapphire (0001) substrates using radio-frequency powder sputtering. The β-Ga₂O₃ : Sn NWs were converted to a porous structure during the vacuum annealing process at 800℃. Host non-stoichiometric Ga₂O_3-x, is transformed into stoichiometric Ga₂O₃, where Sn atoms separate and form Sn nano-clusters that gradually evaporate in a vacuum atmosphere. As a result, the amount of Sn atoms was reduced from 1.31 to 0.27 at%. Pores formed on the sides of β-Ga₂O₃ : Sn NWs were observed. This increases the ratio of the surface to the volume of β-Ga₂O₃ : Sn NWs.

• Korean journal of communication and information
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• v.49
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• pp.20-38
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• 2010

This paper was attempting to identify determinants of media repertoires based on new services and technologies. Using the regression and discriminant models, this study examined determinants that included five independent factors such as the degree of innovation, social networks, social influences, demographic variables and media uses. The analyses revealed that all of independent variables except the degree of innovation were significant determinants of media repertoires. Secondly, the results of discriminant analyses showed that terrestrial television use, age, disposable income were significant factors discriminating new media service adopters from the sample. For new media related technologies adopters, family income, and media uses such as newspaper, Internet and radio were significant discriminant variables.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.51-60
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• 2004

DAB(Digital Audio Broadcasting) is a new media service that can provide CD quality audio, various data service, interactive and high quality mobile communications through popular media such as terrestrial broadcasting, satellite, cable TV, and internet. In this paper, a new EPG(Electronic Program Guide) application model is proposed. The model is based on DAB and combines a DAB receiver and PCs so that it can take advantages of using various multimedia services and plenty of internet contents. The developed EPSD(EPG Provider System on DAB) has Web-based Server/Client structure and povides EPG functionalities to client PCs over internet. Therefore, the DAB receiver can be smaller and cheaper, and can develop abundant data services on internet. It can also provide high quality video services and be expected to become an important component in future home network systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.47-56
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• 2008

An RFID system comprises a reader and a tag, and this paper focuses on a tag design. A UHF tag is activated by energy supply using electromagnetic waves and energy reflection through impedance mismatching. The tag uses a $0.25{\mu}m$ CMOS process and comprises a digital part executing tag protocols, a 512-bit memory, and an analog part having a rectifier, a modulation/demodulation unit, a clock generator, etc. The total dimension of the tag, including a saw line, is $750{\mu}m*750{\mu}m$ and the power consumption of the tag consumption power is about $17.8{\mu}W$ at a supply voltage of 2V.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.277-290
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• 2018

Wind data observed by wind profiler provide wind vectors with the altitudes using PCL1300, wind computation program. As a result of application with parameters set in program currently, it is difficult to compute wind vectors in the upper air over 3 km. This id because a very strict criterion for parameters removes large amounts of data. In this study, therefore, we improve the methods of application by resetting parameters to expand data collection area of wind vectors and reduce underestimation. Although the acquisition rate of the wind vector increased from 72.2% to 92.2%, the RMSE of the wind speed maintained 1.5 m/s - 3.1 m/s, which is less than 15% of the error rate at each altitude.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1039-1046
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• 2016

To study a habit and life patten of a wild animal, this paper do a research on the location tracing system of wild animal by yagi-antenna low pass filter, angle tracking technology. Commonly, VHF Radio Telemetry is used for the location tracing system of wild animal. Considering movement, Previous yagi-antenna has 4-element and has advantage of portability but the other advantages are small and preference is weak. To make the advantage of yagi-antenna higher than previous one, Supposed technology adapt to 6-element and make out Narrow space yagi-antenna technology. Also, It supposes that AOA (:Angle of arrival) technology is applied to detecting technology for a close direction from received signal. Based on this study suggest that position tracing technology is so as to figure out a life patten and habit of a wild animal which live in a certain area.