• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.1
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• pp.70-76
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• 2001

An integrated recirculating aquaculture system suitable to our country's situation was designes and developed, The integrated recirculating aquaculture system consisting of a double drain type rearing tank of the $2.5 m^3$, a sedimentation tank for removal of settleable solids, a floating bead filter for the removal of suspended solids, a foam separator for removal of fine particles and a rotating biological contactor for the nitrification was designed and manufactured. The integrated recirculating aquaculture system was stocked with nile tilapia (Oreochromis niloticus) at $2\%$ rearing density for 2 weeks. Feed coefficient was 1.4 and average daily growth rate was $0.64\%$ in the system for 2 weeks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1833-1839
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• 2017

Korea Railway is enhancing the railway wireless communication system from VHF and TRS which have been used for 100 years to LTE-R starting with Ministry of Science and ICT's allocation of Integrated Public Network Frequency on December 2014. LTE-R has advantages on technology performance, also on ease of evolution based on standardization compared to existing technologies. However there are few problems that need to be solved to provide stable railway wireless services in the future. Due to national spectrum policy, LTE-R has frequency interference with Integrated Public Networks (PS-LTE, LTE-M ) and UHD-TV which was commercialized in 2017. This paper introduces performance changes caused by interferences which were founded from the test bed in Wonju~Gangneung LTE-R project and the result of RAN-Sharing. In addition, this paper suggests the standard for LTE-R cell planning in the case of sharing the Integrated Public Network Frequency by analyzing the changes of designed link-budget factor based on the test result.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.84-88
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• 2006

The effects of tip voltage, deflection setpoint, and tip velocity on height of $SiO_2$ line drawn by local anodization on Si wafer using scanning probe microscope were investigated. No local anodization was detected at smaller than -3 V of tip voltage. The line height increased at rate of 0.47 nm/V when the tip voltage is stronger than -3 V at $1{\mu}m/s$ tip velocity. From deflection setpoint, mechanical force between tip and substrate could be calculated and the threshold farce was $12\sim18nN$. The height of anodized $SiO_2$ lines is independent of the magnitude of force above the threshold force. The line height decreased as increasing the tip velocity and limited to 0.7 nm at -5 V tip voltage.

• Journal of IKEEE
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• v.23 no.3
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• pp.1061-1067
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• 2019

In this paper, a highly integrated 3-channel DC-DC converter is designed using power transistor width scaling (PTWS). For positive voltage, $V_{POS}$, a boost converter is designed using the set-time variable pulse width modultaion (SPWM) dual-mode and PTWS to improve efficiency at light load. For negative voltage, $V_{NEG}$, a 0.5 x regulated inverting charge pump is designed with pulse skipping modulation (PSM) controller to reduce power consumption, and for an additional positive voltage, $V_{AVDD}$, a LDO circuit is designed. The proposed DC-DC converter has been designed using a $0.18{\mu}m$ BCDMOS process. Simulation results show that the proposed converter has power efficiency of 56%~90% for load current range of 1 mA~70 mA and output ripple voltage less than 5 mV at positive voltage.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.729-742
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• 2020

In this study, we analyze seabottom conditions and characteristics integrated with topographic data, seafloor mosaic, underwater images and orthophoto(drone) of soft-hard bottom area around the Sib-Ri rock in the northern shore of the East Sea(Gyeongpo Beach, Gangneung). We obtained field survey data around the Sib-Ri rock(about 600 m × 600 m). The Sib-Ri rock is formed by two exposed rocks and surrounding reef. The artificial reef zone made by about 200 ~ 300 structures is shown the western area of the Sib-Ri rock. The underwater rock region is extended from the southwestern area of the exposed the Sib-Ri rock with 9 ~ 11 m depth range. The most broad rocky seabottom area is located in the southwestren area of the Sib-Ri rock with 10 ~ 13 m depth range. The study area were classified into 4 types of seabottom environment based on the analysis of bathymetric data, seafloor mosaics, composition of sediments and images(underwater and drone). The underwater rock zones(Type I) are the most distributed area around the Sib-Ri Rock(about 600 m × 600 m). The soft seabottom area made by sediments layer showed 2 types(Type II: gS(gravelly Sand), Type III: S(Sand)) in the areas between underwater rock zones and western part of the Sib-Ri rock(toward Gyeongpo Beach). The artificial reef zone with a lot of structures is located in the western part of the Sib-Ri rock. Marine algae(about 6 species), Phylum porifera(about 2 species), Phylum echinodermata(about 3 species), Phylum mollusca(about 3 species) and Phylum chordata(about 2 species) are dominant faunal group of underwater image analysis area(about 10 m × 10 m) in the northwestern part of the Sib-Ri rock. The habitat of Phylym mollusca(Lottia dorsuosa, Septifer virgatus) and Phylum arthropoda(Pollicipes mitella, Chthamalus challengeri hoek) appears in the intertidal zone of the Sib-Ri rock. And it is possible to estimate the range and distribution of the habitat based on the integrated study of orthphoto(drone) and bathymetry data. The integrated visualization and mapping techniques using seafloor mosaic images, sediments analysis, underwater images, orthophoto(drone) and topographic data can provide and contribute to figure out the seabottom conditions and characteristics in the shore of the East Sea.

• The Journal of Korean Association of Computer Education
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• v.6 no.2
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• pp.53-60
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• 2003

The M&S community needs an environmental data representation and interchange mechanism which not only satisfies the requirements of today's systems, but can be extended to meet future data sharing needs. This mechanism must allow for the standard representation of, and access to data. It must support databases containing integrated terrain, ocean, atmosphere, and space data. The SEDRIS provides environment data users and producers with a clearly defined interchange specification. In this paper I present the method to extract the data attributes contained in synthetic environment domain using SEDRIS technology and API.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.4
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• pp.256-261
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• 2011

We demonstrate 3-Gb/s wireless link using a 60-GHz receiver front-end fabricated in $0.25-{\mu}m$ SiGe:C bipolar complementary metal oxide semiconductor (BiCMOS) and a mixed-mode quadrature phase-shift keying (QPSK) demodulator fabricated in 60-nm CMOS. The 60-GHz receiver consists of a low-noise amplifier and a down-conversion mixer. It has the peak conversion gain of 16 dB at 62 GHz and the 3-dB intermediate-frequency bandwidth of 6 GHz. The demodulator using 1-bit sampling scheme can demodulate up to 4.8-Gb/s QPSK signals. We achieve successful transmission of 3-Gb/s data in 60 GHz through 2-m wireless link.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.385-393
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• 2022

In this paper, we consider univariate time series models that are well known in the field of forecasting and we study on forecasting performance for their simple combinations. The univariate time series models include exponential smoothing methods and ARIMA (autoregressive integrated moving average) models, their extended models, and non-seasonal and seasonal random walk models, which is frequently used as benchmark models for forecasting. The median and mean are simply used for the combination method, and the data set used for performance evaluation is M3-competition data composed of 3,003 various time series data. As results of evaluating the performance by sMAPE (symmetric mean absolute percentage error) and MASE (mean absolute scaled error), we assure that the simple combinations of the univariate models perform very well in the M3-competition dataset.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.23-30
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• 2012

In this paper, we suggested the integration between automatic enforcement system and UTIS(Urban Traffic Information System) base station. UTIS base station and automatic enforcement system are different in the height of installation and the type of communication network. UTIS base station is 25 meter high and communicate with center system by optical network. Whereas automatic enforcement system is 6.6 meter high and communicate with center system by rental network. For the purpose of suggesting the efficient method of integration, research was as in the following. We found that the number of integrated system was 1,628 through the present state of analysis and UTIS equipment was satisfied with the required specifications through field testing. Also we suggested the appropriate configuration of the integrated system and analyzed that the cost of the integrated system installment is 1/5 lower than that of the legacy system installment.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.55-61
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• 1999

A convolution algorithm combined with Fourier transformation is applied to the tomographic reconstruction of the asymmetric soot structure to identify the local soot volume fraction distribution. The line of sight integrated data from light extinction measurement with multi-angular scanning form basic information for the deconvolution. Multi-peak following interpolation technique is applied to obtain the effect of increasing number of scanning angles. Measurement of LII signal for the same flame shows the validity of this reconstruction technigue.