• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.321-335
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• 2023

Monitoring sediment loads in natural rivers is the key process in river engineering, but it is costly and dangerous. In practice, suspended loads are directly measured, and total loads, which is a summation of suspended loads and bed loads, are estimated. This study proposes a real-time sediment discharge monitoring system using the horizontal acoustic Doppler current profiler (H-ADCP) and support vector regression (SVR). The proposed system is comprised of the SVR model for suspended sediment concentration (SVR-SSC) and for total loads (SVR-Q_TL), respectively. SVR-SSC estimates SSC and SVR-Q_TL mimics the modified Einstein procedure. The grid search with K-fold cross validation (Grid-CV) and the recursive feature elimination (RFE) were employed to determine SVR's hyperparameters and input variables. The two SVR models showed reasonable cross-validation scores (R²) with 0.885 (SVR-SSC) and 0.860 (SVR-Q_TL). During the time-series sediment load monitoring period, we successfully detected various sediment transport phenomena in natural streams, such as hysteresis loops and sensitive sediment fluctuations. The newly proposed sediment monitoring system depends only on the gauged features by H-ADCP without additional assumptions in hydraulic variables (e.g., friction slope and suspended sediment size distribution). This method can be applied to any ADCP-installed discharge monitoring station economically and is expected to enhance temporal resolution in sediment monitoring.

• Journal of Advanced Navigation Technology
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• v.12 no.2
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• pp.139-145
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• 2008

There has been lots of studies on communication systems using millimeter wave recently in many countries, specially in newly assigned 57GHz ~ 64GHz ISM band. Among those studies, IEEE 802.15.3c standard proposes OFDM (Orthogonal Frequency Division Multiplexing) systems for high data rate transmission support. But OFDM method has the PAPR (peak-to-Average Power Radio) problem The PAPR problem is to decline the performance of the transmission system due to signals distorted severely when passing through nonlinear components such as ADC/DAC and power amplifiers. In order to solve the problem of P APR, this paper suggests SSC (Sine Soft Clipping) and analyzes the PAPR, CCDF, PSD, BER by applying SAW(Surface Acoustic Wave) filter and power amplifiers to IEEE 802.15.3.c OFDM WPAN systems.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3175-3180
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• 2008

A metal-fueled pool-type liquid metal fast reactor (LMFR) provides large margins to sodium boiling and fuel damage under accident conditions. The favorable passive safety results are obtained by both a reactivity feedback mechanism in the core and a passive decay heat removal system. Among the various reactivity feedbacks, the ones by a thermal expansion of a radial dimension of the core and by the control rod drivelines are strongly dependent on the flow conditions in the core and the hot pool, respectively. The effects of multidimensional thermal hydraulic characteristics on these reactivity feedbacks are investigated by the system-wide safety analysis code SSC-K with advanced thermal hydraulics models. Particularly a detailed three dimensional thermal hydraulics reactor core model is integrated into SSC-K for use in a whole system analysis of the passive safety aspects of LMR designs. The model provides fuel and cladding temperatures for every fuel pin in a reactor and coolant temperatures for every coolant sub-channel in the reactor.

• ETRI Journal
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• v.27 no.5
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• pp.484-490
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• 2005

We fabricated 40 Gb/s front-end optical receivers using spot-size converter integrated waveguide photodiodes (SSC-WGPDs). The fabricated SSC-WGPD chips showed a high responsivity of approximately 0.8 A/W and a 3 dB bandwidth of approximately 40 GHz. A selective wet-etching method was first adopted to realize the required width and depth of a tapered waveguide. Two types of electrical pre-amplifier chips were used in our study. One has higher gain and the other has a broader bandwidth. The 3 dB bandwidths of the higher gain and broader bandwidth modules were about 32 and 42 GHz, respectively. Clear 40 Gb/s non-return-to-zero (NRZ) eye diagrams showed good system applicability of these modules.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.21-28
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• 2021

In order to develop a Korea Positioning System (KPS) as part of key national infrastructure, independent navigation signal design is essential. The designed signal candidates must coexist with existing or planned GNSS signals within the limited frequency band. This requires a RF compatibility assessment, which can be performed using the Spectral Separation Coefficient (SSC) and Effective Carrier to Noise Density Ratio (Effective C/N0), for navigation signals. Thus, in this paper, the analysis of RF compatibility between the designed signal candidates and the existing GNSS signals is carried out based on analytical and numerical techniques.

• Journal of the Korean Wood Science and Technology
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• v.41 no.1
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• pp.19-32
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• 2013

In this study, outstanding white rot fungi for biodegradation of organosolv lignin were selected on the basis of their ligninolytic enzyme system. Fifteen white rot fungi were evaluated for their ability to decolorize Remazol Brilliant Blue R (RBBR) in SSC and MEB medium, respectively. Six white rot fungi (Ceriporiopsis subvermispora, Ceriporia lacerate, Fomitopsis insularis, Phanerochaete chrysosporium, Polyporus brumalis, and Stereum hirsutum) decolorized RBBR rapidly in SSC medium within 3 days. The protein contents as well as the activities of manganese peroxidase (MnP) and laccase for 6 selected fungi were determined on the SSC medium with and without organosolv lignin. Interestingly, extracellular protein concentrations were determined to relative higher for S. hirsutum and P. chrysosporium in the presence of organosolv lignin than others. On the other hands, each fungus showed a different ligninolytic enzyme pattern. Among them, F. insularis resulted the highest ligninolytic enzyme activities on incubation day 6, indicating of 1,545 U/mg of MnP activity and 1,259 U/mg of laccase activity. In conclusion, $STH^*$ and FOI were considered as outstanding fungi for biodegradation of organosolv lignin, because $STH^*$ showed high extracellular protein contents and ligninolytic enzyme activities over all, and ligninolytic enzyme activities of FOI were the highest among white rot fungi used in this study.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.328-329
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• 2011

• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.607-614
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• 1998

In this note we shall give a new existence theorem of equilibrium in social systems with coordination under general assump-tions by using the Kakutani fixed point theorem.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.163.1-163
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• 1998

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.799-807
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• 2004

The objective of this field experiment was to investigate the growth, hay yield and chemical composition of cassava and stylo 184 grown under intercropping. The experiment was arranged in a Randomized Complete Block (RCB) design with 5 treatments and 4 replications. The treatments were: sole crop cassava (C); sole crop stylo 184 (S) and three intercropping treatments comprising an additive series of one (SC), two (SSC) and three (SSSC) rows of stylo 184 to one row of cassava. The results showed that leaf area per plant (LA) of cassava was significantly higher (p<0.05) in the sole crop relative to the intercropping treatments. Both total hay yield and CPDM yield were significantly higher (p<0.05) for C treatment and lower (p<0.05) for SSSC treatment. The total hay yield and CPDM yield were significantly greater (p<0.05) in the sole crop relative to the intercropping treatments. At the first and second harvests, CP content was similar among treatments; while at third and fourth harvests, CP contents were significantly greater (p<0.05) for the intercropping treatment relative to the sole crop. At the first and second harvest, NDF contents were significantly greater (p<0.05) in the sole crop relative to the intercropping treatments, whereas NDF contents were similar among intercropping treatments. Leaf area of stylo 184 at first and second harvest were significantly greater (p<0.05) for C, SC and SSC as compared with the SSSC treatments. At each harvesting, there were no significant differences in ash, CP, NDF, ADF and ADL contents of stylo 184 hay between the sole crop and intercropping treatments, except for the first harvest. ADF contents were significantly greater (p<0.05) in S, SC treatments relative to SSC and SSSC treatments. Both collective hay yield and CPDM yield of cassava and stylo 184 were significantly greater (p<0.05) for the SSC treatment and significantly lower (p<0.05) for the S treatment. Collective hay yield and CPDM yield were significantly greater (p<0.05) for the intercropping treatments relative to the sole crop. Based on this research, it was concluded that stylo 184 showed potential for intercropping with cassava. Intercropping cassava with stylo 184 has beneficial effects and can improve foliage biomass yield and soil fertility, which would be a more sustainable system than growing the cassava as a pure stand. In terms of hay yield and CP production, two rows of stylo 184 to one row of cassava could be the optimal pattern for this intercropping system.