• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1104-1109
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• 2015

Due to the rapid growth in digital contents, it is important for us to design a high speed and secure encryption algorithm which is able to comply with the existing and future needs. This paper proposes an alternative approach for self-decimated LM-128 summation sequence generator, which will generate a higher throughput if compared to the conventional generator. We design and implement a threshold clock-controlled LM-128 and prove that it has a lower clock cycle and hence giving a higher key stream generation speed. The proposed threshold clock-control LM-128 generator consists of 256 bits inner state with 128 bits secret key and initialization vector. The cipher achieves a security level of 128 bits to be adapted to the digital contents security with high definition and high quality.

• The KIPS Transactions:PartA
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• v.9A no.1
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• pp.93-98
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• 2002

This paper introduces the design of high-speed analog-to-digital converter (ADC) for hard disk drive (HDD) read channel applications. This circuit is bated on fast regenerative autozero comparator for high speed and low-error rate comparison operation, and Double Speed Dual ADC (DSDA) architecture for efficiently increasing the overall conversion speed of ADC. A new type of thermometer-to-binary decoder appropriate for the autozero architecture is employed for no glitch decoding, simplifying the conventional structure significantly. This ADC is designed for 6-bit resolution, 800 Msample/s maximum conversion rate, 390 mW power dissipation, one clock cycle latency in 0.65 m CMOS technology.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.197.1-197.1
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• 2011

Target generation capacity of geothermal power generation pilot plant project through the Enhanced Geothermal Systems (EGS) with a doublet system down to 5 km depth was estimated. Production and re-injection temperatures of geothermal fluid were assumed $160^{\circ}C$ and $60^{\circ}C$, respectively, based on reservoir temperature of $180^{\circ}C$ calculated from the geothermal gradient of $33^{\circ}C$ in Pohang area. In this temperature range, 0.11 of thermal efficiency of the binary generation cycle is a practical choice. Assuming flow rates of 40 kg/sec, which is possible in current EGS technology, gross power generation capacity is estimated to reach 1.848 MW. Net generation considering auxiliary power including pumping power for geothermal fluid and condensing (cooling) energy of working fluid can be 1.5 MW.

• Clean Technology
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• v.23 no.4
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• pp.421-428
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• 2017

In this study, we have investigated the characteristics of adsorption and desorption of toluene, methyl ethyl ketone (MEK) and their binary component using activated carbon. The BET analysis was performed to identify the characteristics of the activated carbon, and the desorption characteristics with temperature were examined to find out an optimum desorption temperature. Ten cyclic experiments of adsorption-desorption were performed, where each adsorption temperature was maintained at room temperature and desorption temperature at upto $120^{\circ}C$. In case of single component cyclic test, the efficiencies of adsorption and desorption decreased as the cycle increased. MEK which has lower affinity with activated carbon than toluene showed lower efficiencies of adsorption and desorption. In case of binary component cyclic test, a typical roll-up phenomenon was observed during adsorption process, where MEK reaches at breakpoint first and then was swept out by toluene.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.462-469
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• 2016

This paper presents the results of thermodynamic cycle analysis and performance tests of alternative mixtures in low temperature applications. Two near-azeotropic binary mixtures R-152a/R-1270 (35:65 by wt.%) and R-290/E170 (35:65 by wt.%) are considered in this study. They have zero ODP (Ozone Depletion Potential) and much lower GWP (Global Warming Potential) than R-404A which is an alternative of R-502. Refrigeration cycle characteristics such as cooling capacity, coefficient of performance, suction and discharge pressures and temperatures are compared to those for the baseline refrigerants (R-502 and R-404A) cycles. The performance tests are conducted at the evaporation and condensation temperatures of $5^{\circ}C$ and $45^{\circ}C$, subcooling and superheating temperatures of $5^{\circ}C$, respectively. Performance comparisons between baseline and alternative refrigerants are conducted on the same cooling capacity. The system performance of newly proposed refrigerant mixtures show promising results.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.109-117
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• 2011

Since the thermal performance of cycles for use of low-temperature source is low if a pure working fluid is used, the cycles using ammonia-water binary mixture as a working fluid has attracted much attention over past two decades. Recently, several commercial power plants using Kalina cycles have been built and being operated successfully. In this work thermodynamic performance of Kalina cycles using ammonia-water mixture as a working fluid is investigated for the purpose of extracting maximum power from low-temperature energy source. Special attention is paid to the effect of system parameters such as concentration of ammonia and turbine inlet pressure on the characteristics of the system. Results show that the system performance is influenced sensitively by the ammonia concentration, and the role of the performance of heat exchangers is crucial.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.1-8
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• 2008

Low Density Parity Check codes(LDPC) are recently focused on communication systems due to its good performance. The standard of WiBro has also included LDPC codes as a channel coding. The weak point of implementation for LDPC encoder is that conventional binary Matrix Vector Multiplier has many clock cycles which limit throughput. In this paper, we propose semi-parallel architecture by using cyclic shift registers and exclusive-OR without conventional Matrix Vector Multipliers over the standard parity check matrices with Circulant Permutation Matrices(CPM). Furthermore, multi-rate encoder is designed by using proposed architecture. Our encoder with multi-rate for IEEE 802.16e LDPC has lower clock cycles and higher throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.15-20
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• 2023

Until now, Pollard's Rho algorithm has been known as the most efficient way for discrete algebraic problems to decrypt symmetric keys. However, the algorithm is being studied on how to further reduce the complexity of O(${\sqrt{p}}$) performance, along with the disadvantage of having to store the giant stride m=⌈${\sqrt{p}}$⌉ data. This paper proposes an array method for cycle detection in discrete logarithms. The proposed method reduces the number of updates of stack memory by at least 73%. This is done by only updating the array when (x_i<0.5x_i-1)∩(x_i<0.5(p-1)). The proposed array method undergoes the same number of modular calculation as stack method, but significantly reduces the number of updates and the execution time for array through the use of a binary search method.

• Journal of Korea Water Resources Association
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• v.57 no.3
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• pp.165-179
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• 2024

It is crucial to have a comprehensive understanding of inundation and water cycle in urban areas for mitigating flood risks and sustainable water resources management. In this study, we developed a Cellular Automata-based integrated Water cycle model (CAW). A comparative analysis with physics-based and conventional cellular automata-based models was performed in an urban watershed in Portland, USA, to evaluate the adequacy of spatiotemporal inundation simulation in the context of a high-resolution setup. A high similarity was found in the maximum inundation maps by CAW and Weighted Cellular Automata 2 Dimension (WCA2D) model presumably due to the same diffuse wave assumption, showing an average Root-Mean-Square-Error (RMSE) value of 1.3 cm and high scores of binary pattern indices (HR 0.91, FAR 0.02, CSI 0.90). Furthermore, through multiple simulation experiments estimating the effects of land cover and soil conditions on inundation and infiltration, as the impermeability rate increased by 41%, the infiltration decreased by 54% (4.16 mm/m²) while the maximum inundation depth increased by 10% (2.19 mm/m²). It was expected that high-resolution integrated inundation and water cycle analysis considering various land cover and soil conditions in urban areas would be feasible using CAW.

• Journal of IKEEE
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• v.18 no.3
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• pp.356-361
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• 2014

This paper proposes hardware architecture of HEVC (high efficiency video coding) CABAC (context-based adaptive binary arithmetic coding) binarizer. The proposed binarizer was designed and implemented as an independent module that can be integrated into HEVC CABAC encoder. It generates each bin string of each syntax element in a single cycle. It consists of controller module, TU (truncated unary binarization) module, TR (truncated Rice binarization) module, FL (fixed length binarization) module, EGK (k-th order exp-Golomb coding) module, CALR (coeff_abs_level_remaining) module, QP Delta (cu_qp_delta_abs) module, Intra Pred (intra_chroma_pred_mode) module, Inter Pred (inter_pred_idc) module, and Part Mode (part_mode) module. The proposed binarizer was designed in Verilog HDL, and it was implemented in 45 nm technology. Its operating speed, gate count, and power consumption are 200 MHz, 1,678 gates, and 50 uW, respectively.