• 전기전자학회논문지
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• 제27권4호
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• pp.425-429
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• 2023

본 논문에서는 reconfigurable intelligent surface(RIS)의 능동소자를 활성화하는 기법을 제안한다. 최근 RIS는 무선 통신 시스템에서 통신 커버리지와 주파수 효율을 향상기키는 기술로 주목받고 있다. RIS는 수신받는 신호의 위상과 진폭을 조절할 수 있는 기술로 도심과 같이 장애물이 많은 지역에 활용하면 더 좋은 통신 성능을 보장할 수 있다. 하지만 RIS에 의해 신호는 두 번의 페이딩을 겪게 되고 이에 따라 통신 성능의 저하가 발생한다. 최근 이러한 문제를 해결하기 위해 능동 반사 소자를 활용한 RIS가 연구되고 있다. 하지만 RIS 전체를 능동 반사 소자로 활용하게 되면 에너지 소비량이 증가하게 된다. 이에 본 논문에서는 RIS 반사 소자 중 일부만 능동 반사 소자로 활용하는 시스템을 제안하고 활성화되는 능동 반사 소자를 선택하는 기법에 대해 제안한다.

• STI Policy Review
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• 제5권1호
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• pp.112-130
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• 2014

Many actors are involved in the development of regional innovation systems (RIS) such as universities, private firms, research institutions, governments, and public agencies. In a country like Korea, where the central government takes more than 95% of the total government R&D budget, the role of regional authorities in science, technology, and innovation are fairly limited, although in recent years some regional governments have tried to promote innovation activity in their localities. This paper looks into the Gyeonggi Institute of Science and Technology Promotion (GSTEP) in Gyeonggi Province and examines its emerging role and achievements in innovation policymaking. It was found out that GSTEP engages in knowledge brokering with the purpose of helping firms participate in regional technological innovation processes. The knowledge brokering roles of this regional authority are described along with their implications for regional innovation policy. This study aims for a deeper understanding of the nature of the regional authority's role in a RIS through the case study of regional actors transitioning from being subordinators to becoming active participants with greater participation on policymaking and implementation.

• 생명과학회지
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• 제22권6호
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• pp.852-856
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• 2012

한약재의 원료 및 전세계적 외래종으로 알려져 있는 녹조류 청각(Codium fragile)의 디클로로메탄, 에탄올, 열수 추출물을 대상으로 하여 생쥐에서의 항 염증, 해열, 및 진통 활성을 조사하였다. 청각의 디클로로메탄과 에탄올 추출물은 phorbol 12-myristate 13-acetate로 유도된 생쥐 귀의 부종과 충혈에 대한 염증 증상을 74% 이상의 높은 저해 작용을 보였으며, 이들 추출물은 acetyl salicylic acid와 유사하게 발열증상을 억제하였다. 청각으로부터 주된 항 염증 활성물질은 eicosapentaenoic acid인 것으로 분리되었다. 이러한 결과는 청각이 여러 염증 관련 증상에 대처할 약제로서도 사용되어 질 수 있다는 사실을 뒷받침해 준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권3호
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• pp.490-508
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• 2013

One of the most important scalability issues facing the current Internet is the rapidly increasing rate of BGP updates (BGP churn), to which route flap and path exploration are the two major contributors. Current countermeasures would either cause severe reachability loss or delay BGP convergence, and are becoming less attractive for the rising concern about routing convergence as the prevalence of Internet-based real time applications. Based on the observation that highly active prefixes usually repeatedly explore very few as-paths during path exploration, we propose a router-level mechanism, Path Exploration Aggregation (PEA), to scale BGP without either causing prefix unreachable or slowing routing convergence. PEA performs aggregation on the transient paths explored by a highly active prefix, and propagates the aggregated path instead to reduce the updates caused by as-path changes. Moreover, in order to avoid the use of unstable routes, PEA purposely prolongs the aggregated path via as-path prepending to make it less preferred in the perspective of downstream routers. With the BGP traces obtained from RouteViews and RIPE-RIS projects, PEA can reduce BGP updates by up to 63.1%, shorten path exploration duration by up to 53.3%, and accelerate the convergence 7.39 seconds on average per routing event.

• Preventive Nutrition and Food Science
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• 제20권2호
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• pp.119-125
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• 2015

The biologically active compounds raphasatin and sulforaphene are formed during the hydrolysis of radishes by an endogenous myrosinase. Raphasatin is very unstable, and it is generated and simultaneously degraded to less active compounds during hydrolysis in aqueous media. This study determined the hydrolysis conditions to maximize the formation of raphasatin and sulforaphene by an endogenous myrosinase and minimize their degradation during the hydrolysis of radish roots. The reaction parameters, such as the reaction medium, reaction time, type of mixing, and reaction temperature were optimized. A stability test for raphasatin and sulforaphene was also performed during storage of the hydrolyzed products at $25^{\circ}C$ for 10 days. The formation and breakdown of raphasatin and sulforaphene in radish roots by endogenous enzymolysis was strongly influenced by the reaction medium, reaction time, and type of mixing. The production and stabilization of raphasatin in radishes was efficient in water and dichloromethane with shaking for 15 min at $25^{\circ}C$. For sulforaphene, the favorable condition was water as the reaction medium without shaking for 10 min at $25^{\circ}C$. The maximum yields of raphasatin and sulforaphene were achieved in a concurrent hydrolysis reaction without shaking in water for 10 min and then with shaking in dichloromethane for 15 min at $25^{\circ}C$. Under these conditions, the yields of raphasatin and sulforaphene were maximized at 12.89 and $1.93{\mu}mol/g$ of dry radish, respectively. The stabilities of raphasatin and sulforaphene in the hydrolyzed products were 56.4% and 86.5% after 10 days of storage in water and dichloromethane at $25^{\circ}C$.