• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.2
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• pp.277-281
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• 2007

We investigated fault current limitation characteristics of the resistive superconducting fault current limiter (SFCL) which consisted of a Bi-2212 bulk coil and a shunt coil. The Bi-2212 bulk coil and the shunt coil were connected in parallel. The Bi-2212 bulk coil was placed inside the shunt coil to induce field-assisted quench. The fault test was conducted at an input voltage of $200V_{rms}$ and fault current of $12kA_{rms}\;and\;25kA_{rms}$. The fault conditions were asymmetric and symmetric, and the fault period was 5 cycles. The test results show that the SFCL successfully limited the fault current of $12kA_{rms}\;and\;25kA_{rms}$ to below $5.5{\sim}6.9kA_{peak}\;within\;0.64{\sim}2.17$ msec after the fault occurred. Limitation was faster under symmetric fault test condition due to the larger change rate of current. We concluded that the speed of fault current limitation was determined by the speed of current rise rather than the amplitude of a short circuit current. These results show that the Bi-2212 bulk coil is suitable for distribution-class SFCLS.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.656-661
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• 2017

To develop a highly value-added product from extract from small and damaged sea mussels Mytilus edulis, we prepared two types of sea mussel sauce (MS): bottled (BMS) and retort pouched (RMS). We investigated the processing conditions, quality metrics and flavor compounds in each type of sauce. We found that the most appropriate base formulation for both BMS and RMS consisted of 40.0% SME (Brix $30^{\circ}$), 15.0% sugar, 6.0% salt, 4.0% monosodium glutamate, 4.0% soy sauce, 3.5% starch, 3.0% yeast extract, 3.5% wheat flour and 21.0% water. The crude protein, salinity, volatile basic nitrogen and amino-nitrogen content of the BMS and RMS were 8.7% and 8.8%, 9.3% and 9.2%, 24.9 and 31.4 mg/100 g, and 468.5 and 455.1 mg/100 g, respectively. For comparison, the ranges of these values in commercial oyster sauces (COS) are 4.7-7.5%, 10.7-12.0%, 8.2-12.5 mg/100 g, and 225.7-448.2 mg/100 g, respectively. The total free amino acid content of RMS and Premium COS was 7,215.7 and 6,160.7 mg/100 g, respectively, and the main free amino acids were glutamic acid, taurine, glycine, alanine, arginine, proline and lysine. These results demonstrate that BMS and RMS have favorable organoleptic qualities and good storage stability compared to COS, and are suitable for commercialization as high-flavor seasoning sauces.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.341-346
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• 2014

This paper has presented the design and fabrication of phase correlator for wideband digital frequency discriminator (DFD) operating over the 6.0 to 18.0 GHz frequency range. Fabricated DFD phase correlator has been measured I or Q output signal, and analyzed frequency discrimination error. The operation of the proposed mixer type correlator has been analyzed by deriving some analytic equations. To design the phase correlator, this paper has modeled and simulated IQ mixer and 8-way power divider by using RF simulation tool. Designed phase correlator has fabricated and measured. The phase error and frequency discrimination error have been presented using by measured I and Q output signal. Over the 6.0~18.0 GHz range, the root mean square(RMS) phase error is $4.81^{\circ}$, RMS and frequency discrimination error is 1.49 MHz, RMS.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.8-20
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• 2011

Atmospheric visibility is one of the indicators used to evaluate the status of air quality. Based on a conceptual definition of visibility as the maximum distance at which the outline of the selected target can be recognized, an image analysis technique is introduced here and an algorithm is developed for visibility monitoring. Although there are various measurement techniques, ranging from bulk and precise instruments to naked eye observation techniques, each has their own limitations. In this study, a series of image analysis techniques were introduced and examined for in-situ application. An imaging system was built up using a digital camera and was installed on the study sites in Incheon and Seoul separately. Visual range was also monitored by using a dual technology visibility sensor in Incheon and transmissometer in Seoul simultaneously. The Sobel mask filter was applied to detect the edge lines of objects by extracting the high frequency from the digital image. The root mean square (RMS) index of variation among the pixels in the image was substantially correlated with the visual ranges in Incheon and Seoul with correlations of $R^2$=0.88 and $R^2$=0.71, respectively. The regression line equations between the visual range and the RMS index in Incheon and Seoul were VR=$2.36e^{0.46{\times}(RMS)}$ and VR=$3.18e^{0.15{\times}(RMS)}$, respectively. It was also confirmed that the fine particles ($PM_{2.5}$) have more impacts to the impairment of visibility than coarse particles.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.639-640
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• 2006

We investigated fault current limitation characteristics of the resistive superconducting fault current limiter(SFCL) which consisted of a Bi-2212 bulk coil and a shunt coil. The Bi-2212 bulk coil and the shunt coil were connected in parallel. The Bi-2212 bulk coil was placed inside the shunt coil to induce field-assisted quench. The fault test was conducted at an input voltage of 200 $V_{rms}$ and fault current of 12 $kA_{rms}$ and 25 $kA_{rms}$. The fault conditions were asymmetric and symmetric, and the fault period was 5 cycles. The test results show that the SFCL successfully limited the fault current of 12 $kA_{rms}$ and 25 $kA_{rms}$ to below $5.5{\sim}6.9kA_{peak}$ within $0.64{\sim}2.17$ msec after the fault occurred. Limitation was faster under symmetric fault test condition due to the larger change rate of current. We concluded that the speed of fault current limitation was determined by the speed of current rise rather than the amplitude of a short circuit current. These results show that the Bi-2212 bulk coil is suitable for distribution-class SFCLs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.281-285
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• 2001

According to standard procedures as defined in the users handbook for sea level data processes, I was compared to Topex/poseidon sea level data from the first 350days of mission and Tide Gauge sea level data from the Amsterdam- Crozet- Kerguelen region in the South Indian Ocean. The comparison improves significantly when many factors for the corrections were removed, then only the aliased oceanic tidal energy is removed by oceanic tide model in this period. Making the corrections and smoothing the sea level data over 60km along-track segments and the Tide Gauge sea level data for the time series results in the digital correlation and RMS difference between the two data of c=-0.12 and rms=11.4cm, c=0.55 and rms=5.38cm, and c=0.83 and rms=2.83cm for the Amsterdam, Crozet and Kerguelen plateau, respectively. It was also found that the Kerguelen plateau has a comparisons due to propagating signals(the baroclinic Rossby wave with velocity of -3.9~-4.2cm/sec, period of 167days and amplitude of 10cm) that introduce temporal lags($\tau$=10~30days) between the altimeter and tide gauge time series. The conclusion is that on timescales longer than about 10days the RMS sea level errors are less than or of the order of several centimeters and are mainly due to the effects of currents rather than the effects of sterics(water temperature, density) and winds.

• Physical Therapy Rehabilitation Science
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• v.9 no.2
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• pp.120-130
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• 2020

Objective: This study was conducted to identify the clinical usefulness, validity, and reliability of the Spirokit, a device that combines the pulmonary function test (PFT) and respiratory muscle strength (RMS) test. Design: Cross-sectional study. Methods: Forty young adults (male: 23, female: 17) participated in a PFT and a RMS test. The concurrent validity for pulmonary function was assessed by comparing data obtained from MicroQuark and the Spirokit and the agreements between the MicroRPM and the Spirokit for RMS were compared. The test-retest reliability of the Spirokit was determined by comparing data obtained from the first and second sessions. The test and retest were performed at the same time after one day for the PFT and RMS test. Validity was estimated using intraclass correlation coefficients (ICCs), and by calculating 95% limits of agreement (LoA). To estimate interrater reliability, ICCs were calculated. Results: The Spirokit showed a high agreement intra class coefficient (ICC [2, 1]): 0.978-0.999, 95% limits of agreements (95% LOA): -0.798 to 0.847 with MicroQuark. It also showed a high level of concordance ICC (2, 1): 0.992 to 0.993, 95% LOA: -9.313 to 11.169 with MicroRPM. The test-retest reliability of the Spirokit was analyzed using ICC (2, 1), and showed a high level of reliability (ICC [2,1]=0.960 to 0.998). Standard error of measurement % (SEM%) was 0.12% to 3.39%, and minimum detectable change% (MDC%) was 0.02% to 3.79%, indicating high level of reliability. Conclusions: The Spirokit is a device with high validity and reliability that can be used to simultaneously measure PFT and RMS tests.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.413-420
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• 2010

The ionospheric delay is currently one of the most significant error sources in precise GNSS surveys. The users of single-frequency receivers should apply some kind of ionospheric correction algorithms to remove or model the ionospheric delay. For real-time correction of the ionospheric delay, one can use Klobuchar or NeQuick model provided by navigation messages of GPS and Galileo, respectively. We evaluated the performance of those models by comparing their effectiveness at different seasons and latitudes. For the first test, we computed the vertical total electron content (VTEC) at the permanent GPS site SUWN for four different seasons. As the second test, we picked three sites in Korea (CHLW, SUWN, JEJU) with high, medium, and low latitudes and evaluated the dependency of VTEC on the site latitude. Computed VTEC values were compared with those from the IRI model and Global Ionosphere Maps (GIM). The root-mean-square (RMS) differences of Klobuchar and NeQuick with respect to IRI and GIM were analyzed. As a result, without regard to season and latitude, the RMS differences of NeQuick models were smaller than that of Klobuchar by about 0.01~3.50 TECU.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.933-934
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• 2007

We fabricated and tested a resistive type superconducting fault current limiter (SFCL) based on BSCCO-2212 bulk coils. Each bulk coils of the SFCL was designed to have the rated voltage of 220 $V_{rms}$ and the critical current($I_C$) of 320$\sim$340 A at 77K. Ten components in series, make the SFCL having the rated voltage of 2.2 $kV_{rms}$ for equal quench test. The fault test was conducted at an input voltage of 2.2 $kV_{rms}$ and fault current of 25 $kA_{rms}$. In addition, we examined the endurance characteristics for all bulk coils through repeat fault test. Test results shows that the SFCL successfully limited the fault current of 25$kA_{rms}$ to below $7{\sim}8kA_{p}$ within minimum 1.1msec after fault occurred. All bulk coils quenched together upon faults and shared the rated voltage evenly. The endurance test results show an equivalent among repeat fault test. During the quench process, average temperature of all bulk coils did not exceed 250 K, and the SFCL was totally safe during the whole operation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.131-138
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• 2008

The channel parameters such as RMS delay spread and Doppler frequency have an effect on performance of system. This paper investigates the effect between the Inter-Code Interference (ICI) and the frequency diversity gain in the multi-rate MC-CDMA system. The multi-rate MC-CDMA system has achieved the more variable data rate than the MC-CDMA and moreover it has the better performance than the OFDMA system, because it has achieved the frquency diversity gain. However, the frequency diversity gain and ICI have a trade-off relationship by using the spreading code. Therefore, we have improved the system performance by efficient choice of system parameters. In order to evaluate the effectiveness of the frequency diversify gain and the ICI effect, we perform simulations by altering the Doppler frequency and RMS delay spread.