• The Southeast Asian review
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• v.27 no.3
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• pp.93-135
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• 2017

Due to their geographic proximity to Beijing, the Southeast Asian states under the fallout of the China's growing power are struggling to seek the art of diplomacy to promote their national interests. This study explores why Cambodia previously taking a pro-US strategy after the end of the Cold War has switched to a pro-China one in the context of the rise of G-2 system, the ASEAN regionalism, the country's national interest and Hun Sen's regime legitimation. Theoretically, this study takes a realist constructivist approach and tries to find how realist interests and norms have affected the Hun Sen's regime legitimation. The relationship between China and Cambodia has been deepened by mutual economic interdependence and increasingly stronger Chinese power. Especially, the Chinese massive economic aids and investment have enormously supported the regime legitimation of Hun Sen. On the other hand, The US value diplomacy promoting democracy and human rights has undermined the Hun Sen's legitimacy and strained the two nations' relationship. However, the Hun Sen's pro-China strategy is not to check and balance against US strategic interests and not to recognize the Chinese hegemonic position in Southeast Asia. It is a hedging against the US value diplomacy while maximizing economic and other gains from China. ASEAN has been playing a coordinating role to limit the scope of power politics among big powers and to mitigate its ramifications. Yet, since the US and Chinese interests are so keenly criss-crossing, Cambodia may continue to react to the G-2 system through bilateral relations with them.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.69-81
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• 2021

While the fifth generation (5G) and beyond 5G (B5G) mobile communication networks are being rolled over the globe, several world-wide companies have already started to prepare the sixth generation (6G). Such 6G mobile networks targets ultra-reliable low-latency communication (URLLC). In this paper, we challenge to reduce the inherent latency of existing non-orthogonal multiple access (NOMA) in 5G networks of massive connectivity. First, we propose the novel unipodal binary pulse amplitude modulation (2PAM) NOMA, especially without SIC, which greatly reduce the latency in existing NOMA. Then, the achievable data rates for the unipodal 2PAM NOMA are derived. It is shown that for unequal gain channels, the sum rate of the unipodal 2PAM NOMA is comparable to that of the standard 2PAM NOMA, whereas for equal gain channels, the sum rate of the unipodal 2PAM NOMA is superior to that of the standard 2PAM NOMA. In result, the unipodal 2PAM could be a promising modulation scheme for NOMA systems toward 6G.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1388-1390
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• 2002

Hybrid power system has a power balanced controller to equilibrate generation power with a load demand and it is composed of DC bus-type power systems. And all of power generators in hybrid power system can be equivalent to current-source characteristics. So this paper discusses power balance control for photovoltaic/wind/diesel hybrid power system. And through the results of simulation, the proposed scheme was verified.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.268-270
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• 2005

전력계통을 계획, 운영, 검토, 해석하는데 있어서 가장 필요한 OPF(Optimal Power Flow)는 현재 다방면에서 새로운 알고리즘과 많은 수리적 방법을 통하여 접근하고 있다. 이들의 기반이 되는 조류계산은 많은 신뢰성들을 얻었지만, 현재 실무자 중심으로 구성되고 직접적으로 적절한 발전배분 상태를 계산하는 부분에서는 일부 한계성이 나타나고 있다. 이에 대해서 계속된 반복계산에 의한 최적의 계통 발전 배분상태에 근접한 값을 제시할 수 있는 프로그램을 PSS/E의 IPLAN을 통하여 개발하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.159-160
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• 2012

For renewable energy has been studied by many research. among them, non-pollution and infinite solar energy using solar power system is newly spotlighed. the DC output characteristic of the solar cell, connection to grid and using the inverter is essential to the process of converter DC to AC. in this paper, study the corresponding changes in the efficiency of the inverter and arcing occurs in the inverter, depending on the conditions and regulations in the UL-1699 series arc occurs.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2670-2677
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• 2023

In the nuclear safety studies, a new trend refers to the evaluation of uncertainties as a mandatory component of best-estimate safety analysis which is a modern and technically consistent approach being known as BEPU (Best Estimate Plus Uncertainty). The major objectives of this study consist in performing a study of uncertainties/sensitivities of the major analysis results for a generic CANDU 6 Nuclear Power Plant during Station Blackout (SBO) progression to understand and characterize the sources of uncertainties and their effects on the key figure-of-merits (FOMs) predictions in severe accidents (SA). The FOMs of interest are hydrogen mass generation and event timings such as the first fuel channel failure time, beginning of the core disassembly time, core collapse time and calandria vessel failure time. The outcomes of the study, will allow an improvement of capabilities and expertise to perform uncertainty and sensitivity analysis with severe accident codes for CANDU 6 Nuclear Power Plant.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.185-190
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• 2017

Antioxidative ability of 50% ethanol extract from leaves of Leucaena leucocephala (Lam.) de Wit was investigated. The extraction yield, total polyphenols and total flavonoids of the ethanol extract were $18.3{\pm}0.40%$, $121.3{\pm}11.04{\mu}g$ gallic acid equivalents/mg and $105.2{\pm}2.77{\mu}g$ quercetin equivalents/mg, respectively. The ethanol extract possessed the antioxidative activities such as free radical, cation radical, and nitrite scavenging activities as well as reducing power and lipid peroxidation inhibitory activity. These antioxidative activities of the ethanol extract increased in proportion to the extract concentration. $EC_{50}$ values for free radical scavenging, cation radical scavenging nitrite scavenging, and reducing power were $133.51{\mu}g/mL$, $667.22{\mu}g/mL$, 2.58 mg/mL, and $250.00{\mu}g/mL$, respectively. Polyphenols and flavonoids are suggested to be the key contributors for the antioxidative ability of the ethanol extract from Leucaena leucocephala leaves.

• Advances in Traditional Medicine
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• v.5 no.2
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• pp.92-99
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• 2005

Asclepias curassavica. Linn, an erect, simple (or) much branched perennial herb with a somewhat woody base, belonging to the family Asclepiadaceae. It has been reported to have multiple pharmacological effect of anti-inflammatory, cardiotonic, anticancer, anthelmintic and to treat piles and gonorrhoea. It is to be expected that several activities might be related to a possible antioxidant action from this plant. The hydro alcoholic extract of Asclepias curassavica was tested in vitro for its antioxidant activities, such as DPPH radical, nitric oxide radical, superoxide anion radical, lipid peroxidation assay, hydroxyl radical, reducing power, and total phenol content. The extract exhibited scavenging potential with $IC_{50}$ value of $8.7\;{\mu}g/ml,\;198.4\;{\mu}g/ml\;and\;21.7\;{\mu}g/ml$ for DPPH, nitric oxide and superoxide anion radicals. The values were found to higher than those of Vitamin-C, rutin, and curcumin, as standards. The extract showed 50% protection at the dose of $134.2\;{\mu}g/ml\;and\;41.4\;{\mu}g/ml$ in lipid peroxidation as well as deoxyribose degradation, those values more to that of standard, vitamin E $(IC50\;values,\;119.2\;{\mu}g/ml\;and\;32.5\;{\mu}g/ml,\;respectively)$. The reducing power of the extract depends on the concentration and amount of extract. Since a significant amount of polyphenol could be detected by the equivalent to $0.0495\;{\mu}g$ of pyrocatechol from 1 mg of extract. It can be concluded that hydro alcoholic extract of aerial part of Asclepias curassavica could be considered as potent antioxidant, which makes it suitable for the prevention of human disease.

• Korean Journal of Pharmacognosy
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• v.40 no.1
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• pp.1-5
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• 2009

The antioxidant and anti-diabetes effects were evaluated by the ethanol extracts from Astragalus membranaceus root classified by years using through DPPH radical scavenging activity, hydroxyl radical (${\cdot}OH$) scavenging activity, total phenolic and flavonoid contents, reducing power activity, $\alpha$-amylase and $\alpha$-glucosidase inhibitory activities. $IC_{50}$ values for DPPH radical scavenging activity of ethanol extract from 6 years old root ($749.25{\mu}g/mL$) was higher than 1 year ($1452.67{\mu}g/mL$) and 3 years old root ($1095.61{\mu}g/mL$). 6 years old root showed better effects in ${\cdot}OH$ scavenging activity ($IC_{50}$: $10.58{\mu}g/mL$), reducing power, total phenolic contents ($26.13{\pm}0.79\;Tan\;{\mu}g/mg$, $24.03{\pm}0.74\;Cat\;{\mu}g/mg$) $\alpha$-amylase ($33.33{\pm}0.55%$) and $\alpha$-glucosidase inhibitory activity ($49.71{\pm}1.01%$). On the other hand, total flavonoid compound contents were estimated much higher in 1 year old root ($44.93{\pm}1.35\;Que\;{\mu}g/mg$, $70.32{\pm}2.03\;Rut\;{\mu}g/mg$) than others. Based on these results, It was suggested that 6 years old root of A. membranaceus has a potential candidate for functional cosmetic and medicine.