• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.833-838
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• 2011

RFID system in manufacturing industry is used to collect, categorize, and process the data of products. To install RFID system for a large factory, a large amount of wired data communication network is necessary for RS232 communication. If the installed location of RFID system in the factory is changed or extended, a reinstallment is required for the already installed wired data network. A large amount of time/financial reinvestment is necessary for such reinstallation. By using wireless data communication network, however, the initial installation and reinstallation are very simple. In this paper, we implemented a wireless communication system and RFID system. We used the CC1020 chip for wireless communication system and EM4095 chip for RFID system. CC1020 chip enables highly-reliable data communication, and by setting a simple status register, it can switch between transmitting/receiving status and it can choose the desired frequency of either 400 MHz or 900 MHz. Also, Communication range is 50 m, if external antenna is used. EM4095 is a chip for RFID reader system with the carrier frequency of 125 KHz. This chip can implement the reader system by connecting a small number of components. And EM4100 was used for RFID system. EM4100 is read-only type. Atmega128 is used to control a wireless communication system and RFID system. We confirm that the system can communicate without error up to 50 m from sender. In the paper, the circuit diagram and operation program for CC1020 and RFID system are presented. The system used in the experiment is shown in pictures, and the data movement pattern of CC1020 is shown in the diagram, and the performance of each transmission method is presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.692-700
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• 2014

In this work, satellite FE (finite element) model updating for the prediction of the effect of micro-vibration is described. In the case of satellites launched in low earth orbit, high agility and more mission accomplishments are required by the customer in order to procure many images from satellites. To achieve the goal, many mechanisms, including high capacity wheels and antennas with multi-axis gimbals have been widely adopted, but they become a source of micro-vibration which could significantly deteriorate the quality of images. To investigate the effect due to the micro-vibration in orbit on the ground, a prediction is conducted through an integrated model coupling the measured jitter sources with FE (finite element) model. Before prediction, the FE model is updated to match simulation results with the modal survey test. Subsequently, the quality of FE model is evaluated in terms of frequency deviation error, the resemblance of mode shapes and FRFs (frequency response functions) between test and analysis.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.544-551
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• 2008

QUAL2K enhanced QUAL2E and applied in real fields efficiently incorporates denitrification process, sediment-water interaction process, bottom algae and detritus. Also, the CBOD of QUAL2K is divided into two real parts, one is slow CBOD(sCBOD) and another is fast CBOD(fCBOD). The simulation results of QUAL2E and QUAL2K models in Anyang Stream were compared and analyzed in water quality constituents of DO, BOD, Org-N, NH$_3$-N, NO$_3$-N, Org-P, Dis-P and Chl-a respectively. The similar results were shown in Org-N, NH$_3$-N, Org-P and Chl-a both QUAL2K and QUAL2E models. But the different results were revealed in DO, BOD, Dis-P and NO$_3$-N by the influence of new incorporating processes. DO was shown relatively low values in the effect of bottom algae. BOD which is influenced by particulate organic matter was revealed high values. NO$_3$-N was closed to the real values by the two processes of denitrification and sediment-water interaction. To evaluate the running results of QUAL2K and QUAL2E models, a simple statistical analysis was conducted. According to the statistical analysis, QUAL2K represented less relative error and coefficient of variation than QUAL2E in almost all of constituents. It was found that QUAL2K, which simulates the water quality more realistically, can be applied to control and manage the water problems of river or river-run reservoir effectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.1
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• pp.31-40
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• 1991

This paper described on the availability fo the underwater telemetering by the ulterasonic multi-beam system made as a trial to expand detectable range of the fish school. The ultrasonic multi-beam system consisted of four transducers which reconstructed with the existing net recorder. The experiment for the telemetering carried out in the set net fishing ground. The results obtained are summerized as follows: 1. The detectable distance of a target by the linear arrangement of four transducers increased according to the sea depth and the interval between transducers. 2. When the fish school in the entrance of set net was measured by linear arrangement of transducers it was entered in depth of 2.5~3.5m at near position of leader, and in depth of 3.5~4.5m at near position of door net. 3. The deviations of error between the actual position and the position by transducer in case of the target depth 1m, 1.5m, 2m were 5.9~27.1cm, 3.2~28.9cm, 3.5~25.8cm respectively, and 68.3% probability radius of them were 14.6cm, 17.7cm, 17.0cm respectively. 4. When the fish school in the fish court of set net was measured by plane arrangement of transducer it was entered toward the opposite direction of tide current. 5. The available distance of telemetering by the multi-beam transducer was 1.8km and the telemetering was possible to control everywhere in case of sea depth more than three meters.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.1
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• pp.13-18
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• 2014

Sensor nodes are used for monitoring and collecting the environmental data via wireless sensor network. The wireless sensor network with various sensor nodes draws attention as a key technology in ubiquitous computing. Sensor nodes has very small memory capacity and limited power resource. Thus, it is essential to have energy efficient strategy for the sensor nodes. Since the sensor nodes are operating on the same frequency bands with ISM frequency bands, the interference by the devices operating on the ISM band degrades the quality of communication integrity. In this paper, the convolutional code is proposed instead of ARQ for the error control for the sensor network. The proposed convolutional code was implemented and the BER performance is measured. For the fixed transmitting powers of -19.2 dBm and -25dBm, the BER with various communication distances are measured. The packet loss rate and the retransmission rate are calculated from the measured BER. It is shown that the porposed method obtained about 9~12% and 12-19% reduction in retransmission rate for -19.2 dBm and -25 dBm respectively.

• Clinical and Experimental Pediatrics
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• v.50 no.9
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• pp.896-900
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• 2007

Purpose : The aim of this study was to investigate the speech problems in benign rolandic epilepsy (BRE) according to the seizure focus in EEG and semiology. Methods : Twenty three patients [right origin (13 patients) or left side (10 patients)] who met the BRE criteria by International League Against Epilepsy (ILAE) were prospectively enrolled. We excluded the patients who had abnormal MRI or showed both side spikes in EEG. Computerized Speech Lab was used to assess the speech characteristics of the patients. Results : The error pattern of laryngeal articulation in BRE was exclusively substitution of stop consonants, these errors showed more frequent in the left group (16.0% vs 25.5%). Voice onset time (VOT) of stop consonants and Total duration (TD) of word in both groups were prolonged than normal control group, especially in left group (P<0.05). The first formant of vowel /o/ and second formant of /e/ were significantly decreased in left group (P<0.05). The right group scored wider on pitch range ($192.9{\pm}54.0Hz$) and energy range in spontaneous speech ($14.2{\pm}6.4db$) than the left group ($233.3{\pm}12.5Hz$, $19.4{\pm}9.3db$, respectively, P>0.05). Duration of counting (5 to 9) in left group slower than right group ($8.6{\pm}1.7$ vs $7.9{\pm}1.8sec$). Conclusion : Our data suggested that interictal spikes and seizures in either centrotemporal sides, especially left side group, may induce speech problems. We recommend the logopedic and phoniatric evaluations of speech in BRE patients.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.4
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• pp.308-315
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• 2012

Hebei Spirit Oil Spill that happened in 2007 had prompted the need of revisiting the coastal safety. In response to this, Korea had made an effort to implement VTS in every coastline in the country. There are a lot of theoretical studies on VTS function nowadays, but coastal VTS are less frequently studied. In this paper, performance analysis results and accident prevention activities of Jindo Coastal VTS center were summarized and the Coastal VTS function are investigated. Jindo Coastal VTS covers relatively wide area and various places with various maritime traffic characteristics are the major navigation vessels, which means that it is important to control these vessels. Since the probability of accidents due to human error is relatively high in coastal area due to negligence tendency of crews during coastal area navigation, coastal VTS has to provide sufficient assistance to navigating vessels. Like most harbour VTS, Coastal VTS provides not only main information service, navigational assistance and traffic organization services but also various services related with advanced search-and-rescue assistance, marine national security, maritime crime prevention, oil spill response, traffic services for non-service vessel, and safety supervision for water leisure boats.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.228-237
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• 2009

This paper examines the potential of Ultra-High Definition TV (UD-TV) broadcasting transmission systems beyond HD-TV over cable channel. Firstly, we analyze the trend of TOV(Threshold of Visibility) by extending the OpenCable (J.83 Annex B) system 256QAM which is the standard of Korean and American cable television transmission to 1024QAM, and realize that the OpenCable 1024QAM has nearly 30% higher data rate than 256QAM at the expense of impractically higher TOV (Threshold of Visibility). To achieve practical TOV, we control code rates of inner convolutional coder and replace turbo coder in forward error correction (FEC) part, thereby analyzing the best performance of the OpenCable systems having conventional FEC. In that result, it is necessary to modify conventional FEC of the OpenCable system to achieve under 31.5dB TOV. Moreover we study the potential of UD-TV transmission via two or more TV channels, so called channel bonding, through the Shannon capacity in 6MHz channel and the relationship with next generation A/V codec technologies.

• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.79-90
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• 2007

The AmonRa instrument, the primary payload of the international EARTHSHINE mission, is designed for measurement of deep space albedo from L1 halo orbit. We report the optical design, tolerance analysis and the optical performance of the breadborad AmonRa imaging channel instrument optimized for the mission science requirements. In particular, an advanced wavefront feedback process control technique was used for the instrumentation process including part fabrication, system alignment and integration. The measured performances for the complete breadboard system are the RMS 0.091 wave(test wavelength: 632.8 nm) in wavefront error, the ensquared energy of 61.7%($in\;14\;{\mu}m$) and the MTF of 35.3%(Nyquist frequency: $35.7\;mm^{-1}$) at the center field. These resulting optical system performances prove that the breadboard AmonRa instrument, as built, satisfies the science requirements of the EARTHSHINE mission.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.97-104
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• 2018

Recently, many studies have examined UAVs (unmanned aerial vehicles), which can replace and supplement existing surveying sensors, systems, and images. This study focused on the use of UAV images and assessed the possibility of utilization in areas where it is difficult to obtain GCPs (ground control points), such as disasters. Therefore, 3D (dimensional) pointcloud data were generated using UAV images and the absolute/relative accuracy of the generated model data using GCPs and without GCPs was assessed. The results showed the 3D shape pointcloud generated by UAV image matching was proven if the relative accuracy was set, regardless of whether GCPs were used or not; the quantitative measurement error rate was within 1%. Even if the absolute accuracy was low, the 3D shape pointcloud that had been post processed quickly was sufficient to be utilized when it is impossible to acquire GCPs or urgent analysis is required. In particular, the results can obtain quantitative measurements and meaningful data, such as the length and area, even in cases with the ground reference point surveying and post-process.