• KCID journal
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• v.9 no.1
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• pp.38-47
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• 2002

The Lake Sihwa gradually changes from freshwater lake to saline lake due to inflow of seawater by sluice gates . The changes of lake water are closely related to characteristic and distribution of turbidity and suspended matter. During the period April-Ma

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.639-645
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• 2014

In this paper, the scheme of a single module for simultaneous operation of all-optical computing circuits, namely half adder and half subtractor, are realized using semiconductor optical amplifier (SOA) based logic gates. Optical XOR gate by employing a SOA based Mach-Zehnder interferometer (MZI) configuration is used to get the sum and difference outputs. A carry signal is generated using a SOA-four wave mixing (FWM) based AND gate, whereas, the borrow is generated by employing the SOA-cross gain modulation (XGM) effect. The obtained results confirm the feasibility of our configuration by proving the good level of quality factor i.e. ~5.5, 9.95 and 12.51 for sum/difference, carry and borrow, respectively at 0 dBm of input power.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.222-227
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• 2015

We propose a new and potentially integrable scheme for the realization of an all-optical binary full adder employing two XOR gates, two AND gates, and one OR gate. The XOR gate is realized using a Mach-Zehnder interferometer (MZI) based on a semiconductor optical amplifier (SOA). The AND and OR gates are based on the nonlinear properties of a semiconductor optical amplifier. The proposed scheme is driven by two input data streams and a carry bit from the previous less-significant bit order position. In our proposed design, we achieve extinction ratios for Sum and Carry output signals of 10 dB and 12 dB respectively. Successful operation of the system is demonstrated at 10 Gb/s with return-to-zero modulated signals.

• Journal of Korean Port Research
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• v.13 no.2
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• pp.419-426
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• 1999

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from estuary barrage and basin etc. Mokpo sea area downstreams from a long river and two large basins, the Yongsan river and Yongam-Kumho basins discharging much of water through water gates for the purpose of flood control and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculations were carried out for the analysis of diffusion characteristics due to discharging operation, adapting the results of tidal current simulation ADI methord is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the mode of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.253-261
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• 1999

It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from the estuary barrage and basin, etc. Mokpo sea area has downstream from a long river and two large basins, the Yongsan river and Yongam-Kumho basins, discharging much of water through water gates for the purpose of flood and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculation were carried out for the analysis of diffusion characteristics due to discharging operation, adopting the results of tidal current simulation. ADI method is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the modes of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.

• Progress in Superconductivity
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• v.4 no.1
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• pp.37-41
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• 2002

In this work. we have designed two different kinds of Rapid Single Flux Quantum (RSFQ) OR-gates. One was based on the already developed RSFQ cells and the other was aimed to develop a more compact version. In the first circuit, we used a combination of two D Flip-Flops and a merger and in the other circuit we used a combination of RS Flip-Flops and Confluence Buffer. We tested the circuit performance by using the simulation tools, Xic and Wrspice. We obtained the operation margins of the circuit elements by a margin calculation program, and we obtained the minimum operation margins of $\pm$30%. The circuits were laid out, aimed to fabricate by using the existing KRISS Nb process. KRISS Nb process includes the $Nb／Al_2$$O_3$／Nb trilayer fabricated by DC magnetron sputtering and the reactive ion etching technique for the definition of the features. The major tools used in the layouts were Xic and L-meter.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.222-222
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• 2015

Vietnam is one of the most vulnarable countries affected by climate change and sea level rise. One of the consequences of climate change and sea level rise is the increase of salinity intrusion into the rivers which is challenging to irrigation systems in coastal areas. This indicates the necessary to study the ability of taking water through sluice gates of irrigation systems in coastal zones, especially in the dry season with the effects of climate change and sea level rise in the future. In this paper, Nam Thai Binh irrigation system is selected as a case study. The irrigation system is one of 22 biggest irrigation systems of the Red River delta in Vietnam located in coastal region. The computed duration is selected in dry season to irrigate for Winter-Spring crops. The irrigation water for the study area is taken from different sluice gates along the Red River and the Tra Ly River. In this paper, MIKE-11 model was applied to assess the ability of taking water for irrigation of the study area in current situation and in the context of climate change and sea level rise senario in 2050 (under the medium emissions scenario (B2) published by the Ministry of Natural Resources and Environment of Vietnam published in 2012) with different condition of water availability. The operation of the gates depends on the water levels and sanility conditions. The sanility and water level at different water intake gates of Nam Thai Binh irrigation system were simulated with different senarios with and without climate change and sea level rise. The result shows that, under climate change and sea water level rise, some gates can take more water but some can not take water because of salinity excess and the total water taking from the different gates along the rivers decrease while the water demand is increase. The study indicates the necessary to study quantitatively some recommended solutions in the study area particularly and in coastal region generally in Vietnam to ensure water demand for irrigation and other purposes in the context of climate change and sea level rise in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.331-336
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• 2004

This study focuses on the hardware implementation of fast and low-system-complexity multiplier over GF(2$^{m}$ ). From the properties of an irreducible AOP of degree m. the modular reduction in GF(2$^{m}$ ) multiplicative operation can be simplified using cyclic shift operation. And then, GF(2$^{m}$ ) multiplicative operation can be established using the away structure of AND and XOR gates. The proposed multiplier is composed of m(m+1) 2-input AND gates and (m+1)$^2$ 2-input XOR gates. And the minimum critical path delay is Τ$_{A+}$〔lo $g_2$$^{m}$ 〕Τ$_{x}$ proposed multiplier obtained have low circuit complexity and delay time, and the interconnections of the circuit are regular, well-suited for VLSI realization.n.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.1-10
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• 2004

A cellular array parallel multiplier with parallel-inputs and parallel-outputs for performing the multiplication of two polynomials in the finite fields GF$(2^m)$ is presented in this paper. The presented cellular way parallel multiplier consists of three operation parts: the multiplicative operation part (MULOP), the irreducible polynomial operation part (IPOP), and the modular operation part (MODOP). The MULOP and the MODOP are composed if the basic cells which are designed with AND Bates and XOR Bates. The IPOP is constructed by XOR gates and D flip-flops. This multiplier is simulated by clock period l${\mu}\textrm{s}$ using PSpice. The proposed multiplier is designed by 24 AND gates, 32 XOR gates and 4 D flip-flops when degree m is 4. In case of using AOP irreducible polynomial, this multiplier requires 24 AND gates and XOR fates respectively. and not use D flip-flop. The operating time of MULOP in the presented multiplier requires one unit time(clock time), and the operating time of MODOP using IPOP requires m unit times(clock times). Therefore total operating time is m+1 unit times(clock times). The cellular array parallel multiplier is simple and regular for the wire routing and have the properties of concurrency and modularity. Also, it is expansible for the multiplication of two polynomials in the finite fields with very large m.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.971-981
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• 2009

An objective of this study is as follows: 1) performing sensitivity analysis and parameter estimation of RMA2 and RMA4 models for the West-Nakdong River, 2) drawing up alternatives of gates-operation for water-quality enhancement, and 3) quantitative evaluation of methodology of 'flow-restoration by gates-operation' among 'Comprehensive Plan Improving Water-Quality in the West-Nakdong River(WNR)' with the target water-quality(BOD at Nakbon-N point: below 4.3 mg/L). The parameters for the RMA2 (depth-averaged two-dimensional flow model) and RMA4 (depth-averaged two-dimensional water-quality model) were determined by sensitivity analysis. Result of parameter estimation for RMA2 and RMA4 models is $1,000\;Pa{\cdot}s$ of the eddy viscosity, 20 of the Peclet number, 0.025 of the Manning coefficient, and $1.0\;m^2/s$ of the diffusion coefficient. We have evaluated the effects of water-quality enhancement of the selected alternatives by numerical simulation technique with the models under the steady-state flow condition and the time-variant transport condition. Because of no-resuspension from river bottom and considering BOD as conservative matter, these simulation results slightly differ from real phenomena. In the case of $50\;m^3/s$ of Daejeo-gate inflow, two-dimensional flow pn results result represents that small velocity occurs in the Pyungkang Stream and no flow in the Maekdo River. In the WNR, there occurs the most rapid flow near timhae-bridge. In the WNR, changes of water-quality for the four selected simulation cases(6, 10, 30, $50\;m^3/s$ of the Daejeo-gate inflow) were predicted. Since the Daejeo-Gate and the Noksan-Gate can be opened up to 7 days, it would be found that sustainable inflow of $30\;m^3/s$ at the Daejeo-gate makes BOD in the WNR to be under the target of water-quality.