• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3816-3823
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• 2021

The mechanical features evaluated theoretically using Makishima-Mackenzie's model for glasses xBaO-(50-x) PbO-50P₂O₅ where x = 0, 5, 10, 15, 20, 30, 40, and 50 mol%. Wherefore, the elastic characteristics; Young's, bulk, shear, and longitudinal modulus calculated. The obtained result showed an increase in the calculated values of elastic moduli with the replacement of the PbO by BaO contents. Moreover, the Poisson ratio, micro-hardness, and the softening temperature calculated for the investigated glasses. Besides, gamma and neutron shielding ability evaluated for the barium doped lead phosphate glasses. Monte Caro code (MCNP-5) and the Phy-X/PSD program applied to estimate the mass attenuation coefficient of the studied glasses. The decrease in the PbO ratio has a negative effect on the MAC. The highest MAC decreased from 65.896 cm²/g to 32.711 cm²/g at 0.015 MeV for BPP0 and BPP7, respectively. The calculated values of EBF and EABF showed that replacement of PbO with BaO contents in the studied BPP glasses helps to reduce the number of photons accumulated inside the studied BPP glasses.

• ETRI Journal
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• 제45권1호
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• pp.45-59
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• 2023

In this paper, to optimize the average delay and power allocation (PA) for system users, we propose a resource scheduling scheme for wireless networks based on Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) according to the first fifth-generation standards. For delay minimization, we solve a throughput maximization problem that considers CPOFDM systems with carrier aggregation (CA). Regarding PA, we consider an approach that involves maximizing goodput using an effective signal-to-noise ratio. An algorithm for jointly solving delay minimization through computation of required user rates and optimizing the power allocated to users is proposed to compose the resource allocation approach. In wireless network simulations, we consider a scenario with the following capabilities: CA, 256-Quadrature Amplitude Modulation, millimeter waves above 6 GHz, and a radio frame structure with 120 KHz spacing between the subcarriers. The performance of the proposed resource allocation algorithm is evaluated and compared with those of other algorithms from the literature using computational simulations in terms of various Quality of Service parameters, such as the throughput, delay, fairness index, and loss rate.

• Journal of Communications and Networks
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• 제4권4호
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• pp.344-350
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• 2002

This work summarizes the current state of the art in software radio for 4G systems. Specifically, this work demonstrates that classic radio structures, e.g., heterodyne reception, homodyne reception, and their improved implementations, are inadequate selections for multi-mode reception. This opens the door to software defined radio, a novel reception architecture which promises ease in multi-band, multi-protocol design. The work presents the many advantages of such an architecture, including flexibility, reduced cost via component reduction, and improved reliability via, e.g., the elimination of environmental instability. The work also explains the limitations that currently curtail the widespread use of SDR, including issues surrounding A/D converters, management of software and power, and clock generation. This provides direction for future research to enable the broad applicability of SDR in 4G cellular and beyond.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권3호
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• pp.367-374
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• 2013

The electrical vehicles (EV) with vehicle-to-grid (V2G) capability can be used as loads, energy sources and energy storage in MicroGrid integrated with renewable energy sources. The output power of generators will be reallocated in the considering of V2G. An intelligent unit commitment (UC) with V2G for cost optimization is presented in this paper. A new constraint of UC with V2G is considered to satisfy daily use of EVs. A hybrid optimiza-tion algorithm combined Binary Particle Swarm Optimization (BPSO) with Lagrange Mul-tipliers Method (LMM) is proposed. The difference between results of UC with V2G and UC without V2G is presented.

• 한국재난정보학회 논문집
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• 제6권1호
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• pp.92-119
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• 2010

As the necessity to utilize deep-placed underground spaces is increasing, we have to seriously consider the safety problems arising from the U/G spaces which is a restricted environment. Due to the higher cost of land compensation for above ground area and environmental issues, the plan to utilize deep-placed U/G spaces is currently only being established for the construction of U/G road network and GTX. However it is also expected that the U/G spaces are to be used as a living space because of the growing desires to change the above ground areas into the environmentally green spaces. Accordingly it is necessary to protect the U/G environments which is vulnerable against desasters caused by fire, explosion, flooding, terrorism, electric power failure, etc. properly. We want to introduce the principles of the Quantitative Risk Assessment(QRA) method for preparedness against the desasters arising from U/G environments, and also want to introduce an example of QRA which was implemented for the GOTTHARD tunnel which is the longest one in Europe.

• 통합자연과학논문집
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• 제7권4호
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• pp.260-265
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• 2014

The aim of this study was to assess the in vitro potential of methanolic seed extract of Abelmoschus esculentus as a natural antioxidant. The DPPH activity of the Ethyl acetate soluble fraction (10, 20, 40, 80, and $160{\mu}g/mL$) was increased in a dose dependent manner, which was found in the range of 18.97-90.47% as compared to ascorbic acid 26.44-93.71%. The $IC_{50}$ values of Ethyl acetate soluble fraction (EAES) and ascorbicacid in DPPH radical scavenging assay were obtained to be 28.12 and $18.43{\mu}g/mL$, respectively. Measurement of polyphenol content of the EAES of A. esculentus seed was achieved using Folin-Ciocalteau reagent containing 53.80 mg/g of total phenolic content, which was found signicantly higher when compared to reference standard gallic acid. Similarly total flavonoids and proabthocyanidis of EAES and chloroform soluble fraction (CAES) were found significantly 147 mg/g and 14.24 mg/g respectively when both compared to reference standard quercetin. EAES exhibited high significant lipid peroxidation inhibition effects in a dose-dependent manner, with $IC_{50}$ values of $38.08{\mu}g/mL$, whereas, standard quercetin, with $IC_{50}$ value of $36.67{\mu}g/mL$. All extract/fractions showed dose dependent reducing power ability and these differences were statistically significant (p<0.001). The results obtained in this study clearly indicate that A. esculentus seed has a signicant potential to use as a natural antioxidant agent.

• Journal of Applied Biological Chemistry
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• 제62권2호
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• pp.167-172
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• 2019

Napier grass (Penninsetum purpureum)의 50% 에탄올 추출물의 수율, 폴리페놀 함량 및 항산화 활성을 확인하였다. Napier grass 추출물의 수율은 $6.3{\pm}0.35%$이었고, 총 페놀성 화합물 함량은 $79.6{\pm}3.65{\mu}g$ gallic acid equivalents/mg-추출물로 나타났다. Napier grass 추출물의 유리라디칼과 양이온라디칼 소거능, 환원력, 아질산염 소거능 및 지질과산화 억제능은 모두 추출물의 농도에 비례하여 증가하였다. Napier grass 추출물의 DPPH 유리라디칼에 대한 $EC_{50}$값은 $1,930.0{\mu}g/mL$로 유리라디칼에 대한 소거활성이 높지 않았다. Napier grass 추출물의 ABTS 양이온라디칼 소거, 환원력 및 아질산염 소거에 대한 $EC_{50}$값은 각각 350.0, 840.0 및 $1,470.0{\mu}g/mL$로 나타나 유리라디칼 소거활성에 비해 높은 항산화 능력을 보유하고 있었다. 특히 Napier grass 추출물은 $85.0{\mu}g/mL$의 농도에서 과산화물의 생성을 74.6% 억제할 정도로 뛰어난 지질과산화 억제활성을 보여주었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.381-384
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• 2000

In this paper, we designed and fabricated a low noise amplifier which can be used in W-CDMA. For improving input VSWR and stability an emitter inductance series feedback was used, and for acquiring higer linearity at low current DC bais by-passing method was used. Fabricated low noise amplifier had 15.33 ㏈ power gain, 2.17 ㏈ NF, -9.53 ㏈ $S_{11}$ and -35.91 ㏈ $S_{22}$ at 2.16 GHz, and +5.34 ㏈m II $P_{ 3}$ at 10 MHz channel spacing.g.g.g.

• Journal of Advanced Marine Engineering and Technology
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• 제27권4호
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• pp.487-493
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• 2003

More reliable design of thermal transport. Power acquisition and thermal management systems requires the through understanding of the flow hydrodynamic. the differences and similarities between the two-phase flow characteristics of two-Phase flow influenced by the gravity levels. The data of flow Patterns, void fraction, frictional pressure drop associated with their characteristics were obtained at $\mu\textrm{g}$. 1g and 2g. Flow patterns and void fraction data obtained at three gravity levels were compared with each other and previous models and correlations.

• Korean Journal of Mathematics
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• 제22권3호
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• pp.443-454
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• 2014

In this paper, we give linearization of generalized Fi-bonacci sequences {$g_n$} and {$q_n$}, respectively, defined by Eq.(5) and Eq.(6) below and use this result to give the matrix form of the nth power of a companion matrix of {$g_n$} and {$q_n$}, respectively. Then we re-prove the Cassini's identity for {$g_n$} and {$q_n$}, respectively.