• The Korean Journal of Physiology and Pharmacology
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• 제24권1호
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• pp.101-110
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• 2020

Transient receptor potential canonical 4 (TRPC4) channel is a nonselective calcium-permeable cation channels. In intestinal smooth muscle cells, TRPC4 currents contribute more than 80% to muscarinic cationic current (mIcat). With its inward-rectifying current-voltage relationship and high calcium permeability, TRPC4 channels permit calcium influx once the channel is opened by muscarinic receptor stimulation. Polyamines are known to inhibit nonselective cation channels that mediate the generation of mIcat. Moreover, it is reported that TRPC4 channels are blocked by the intracellular spermine through electrostatic interaction with glutamate residues (E728, E729). Here, we investigated the correlation between the magnitude of channel inactivation by spermine and the magnitude of channel conductance. We also found additional spermine binding sites in TRPC4. We evaluated channel activity with electrophysiological recordings and revalidated structural significance based on Cryo-EM structure, which was resolved recently. We found that there is no correlation between magnitude of inhibitory action of spermine and magnitude of maximum current of the channel. In intracellular region, TRPC4 attracts spermine at channel periphery by reducing access resistance, and acidic residues contribute to blocking action of intracellular spermine; channel periphery, E649; cytosolic space, D629, D649, and E687.

• Human Ecology Research
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• 제59권4호
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• pp.449-463
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• 2021

The aim of this study was to analyze the perceptions and entering status of small business online fashion retailers on portal shopping and fashion shopping malls. Case studies were conducted on a total of 10 research samples. The results were as follows: first, regarding the strategic factors of online fashion stores, 'price competitiveness' is important, especially in portal shopping and low-cost brands; 'product assortment' is important but not essential in all platforms; and 'differentiation' is important to continuously secure loyal customers in fashion shopping malls. Customer satisfaction leads to customer loyalty, and customer loyalty affects the sales conversion rate and brand growth of online sales channels. Factors that promoted sales activities in online sales channels were exposure, advertisements, SNS, events, special exhibitions, and events. Hindrance factors were low price competition, overheated competition, and the MD of sales channels. Second, the research samples used multiple online sales channels, including portal shopping malls and fashion shopping malls, in addition to their own malls. The selection factors were platform reputation and commission, branding, and customer inflow through exposure. Portal shopping malls were perceived as providing easy access, advertising/customer communication, exposure/search, price competitiveness, scalability, and intense competition, whereas fashion shopping malls were perceived as providing a brand image and concept, brand promotion, high commissions, difficult entry, and low profits. The factors for success in portal shopping malls were exposure/search, price competitiveness, and brand recognition, whereas the factors for success in fashion shopping malls were differentiation, brand, exposure/advertisement, product assortment, and MD.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.447-450
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• 2009

본 논문에서는 2PAM(binary pulse-antipodal modulation) DS(direct-sequence) UWB(ultra-wideband) 시스템을 V-BLAST(vertical bell lab layered space-time) 구조를 사용하는 MIMO(multiple input multiple output) 시스템에 적용하여 실내 무선 채널 환경에서 고속 데이터 전송률을 달성하고자 한다. 이러한 2PAM DS UWB MIMO 시스템의 BER 성능과 송수신 안테나의 차원과의 관계가 논의된다. 또한, UWB-MIMO 시스템의 수신기에서는 ZF(zero-forcing), ZF-OSIC(ordered successive interference cancellation), MMSE(minimum-mean-square-error), MMSE-OSIC, ML(maximum likelihood)과 같은 다양한 MIMO(multiple input multiple output)와 같은 다양한 MIMO 검출기법이 비교, 분석된다.

• 한국정보통신학회논문지
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• 제14권3호
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• pp.581-586
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• 2010

MC-DS-CDMA 전송 방식에서는 서로 직교성이 있는 여러 개의 부반송파들을 사용함으로서 주파수 다이버시티 효과를 얻을 수 있어 우수한 성능의 전송이 가능하다. 시변 페이딩 채널은 전송되는 MC-DS-CDMA 신호에 인접 부 반송파 간섭을 발생시켜 수신단에서 데이터 재생 시 비트오류율이 증가된다. 본 논문에서는 파일럿 심볼을 이용하여 채널을 추정하는 MC-DS-CDMA 시스템에서 선호가 시변 채널을 통하여 전송될 때의 시스템 성능을 분석한다. 이러한 다중 반송파 전송 방식에서는 채널 추정 에러, 송수산간 반송 주파수 편차 등에 의하여 시스템 성능이 열화 된다. 그러므로 위와 같은 영향들을 모두 고려하여 송선 신호가 다중 경로 페이딩 채널을 통하여 전송될 때의 데이터 비트오류율 성능을 분석한다.

• Smart Structures and Systems
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• 제16권4호
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• pp.593-606
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• 2015

This paper presents a novel concept of healing some of the damages in wind turbine blades (WTBs) such as cracks and delamination. This is achieved through an inherent functioning autonomous repairing system. Such wind turbine blades have the benefit of reduced maintenance cost and increased operational period. Previous techniques of developing autonomous healing systems uses hollow glass fibres (HGFs) to deliver repairing fluids to damaged sites. HGFs have been reported with some limitations like, failure to fracture, which undermines their further usage. The self-healing technique described in this paper represents an advancement in the engineering of the delivery mechanism of a self-healing system. It is analogous to the HGF system but without the HGFs, which are replaced by multiple hollow channels created within the composite, inherently in the FRP matrix at fabrication. An in-house fabricated NACA 4412 WTB incorporating this array of network hollow channels was damaged in flexure and then autonomously repaired using the vascular channels. The blade was re-tested under flexure to ascertain the efficiency of the recovered mechanical properties.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.154-156
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• 2008

A prototype of the desiccant cooling system with a regenerative evaporative cooler was built and tested for the performance evaluation. The regenerative evaporative cooler is to cool a stream of air using evaporative cooling effect without an inc6rease in the humidity ratio. It is comprised of multiple pairs of dry and wet channels and the evaporation water is supplied only to the wet channels. By redirecting a portion of the air flown out of the dry channel into the wet channel, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature at the outlet end of the dry channels. Incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in the desiccant rotor that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners. At the ARI condition with the regeneration temperature of $60^{\circ}C$, the prototype showed the cooling capacity of 4.4 kW and COP of 0.75.

• 유통과학연구
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• 제16권5호
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• pp.61-70
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• 2018

Purpose - These days, an individual user, private entity, hears everyday news of hacking and personal information leakage in the era of a most-connected society. This study investigates cyber attack, cyber insurance and distribution channels for insurance goods in South Korea by analyzing various cases of cyber attacks in domestic and overseas case. Research design, data and methodology - This study adopted various study cases instead of the one large case for deep quality analysis, and focused on various cases of domestic and overseas cyber attacks with insurance. Result - As a result of analyzing the cases that were hacked, types of massive losses and damages arising out of internet blackout due to cyber risks are paralyzation of public and private website and portal, electronic administrative system, public infrastructure, and consequently a normal operation of nation is impossible. These losses and damages however can be coverable under cyber insurance. Conclusions - This paper suggests insurance carriers, as suppliers, should provide multiple channels to sell to the customer and should expand the strategy of advertisement and promotion in order for them to change their mind and compare the price and value of the information of individual users and private entity in view of cost savings.

• 한국위성정보통신학회논문지
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• 제12권1호
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• pp.34-37
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• 2017

본 논문은 I/Q 채널을 다 이용하여 표적의 후퇴와 접근을 감지하는 연속파 레이다의 신호처리에 대하여 분석한다. 표적이 레이다로부터 접근 혹은 후퇴할 때 Quadrature 신호의 위상이 달라지는 것을 이용하여 물체의 후퇴와 접근을 감지하며, 상용 MMIC칩과 MCU를 이용하여 모듈을 구현하고, MMIC로부터 나온 수신데이터를 분석하여 검증하였다. 또한 사람을 대상으로 접근, 후퇴하는 동작에 대한 신호처리를 MCU를 사용하여 확인하였다. 사용한 주파수는 24.125GHz이며, 송신기 출력전력은 7.2 dBm이다. 실제 구현한 레이다로 최대 검출가능거리는 약 12m를 달성하였다.

• 한국콘텐츠학회논문지
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• 제13권2호
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• pp.71-80
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• 2013

이 연구는 PP(방송채널사용사업) 현황을 진단하고, 특히 독립 PP의 실상을 구체적으로 파악하고자 이루어졌다. 이를 위해 14개 독립 PP를 선정하여 심층인터뷰를 진행하였으며, 독립 PP의 문제를 경영, 제작, 콘텐츠의 세 측면에서 분석하였다. 연구결과 독립 PP는 MPP에 비해 경영, 제작, 콘텐츠 모두에서 열악한 위상을 가지고 있음을 발견하였다. 독립 PP의 경영 구조는 매우 취약하였으며, 제작 환경도 좋지 않았다. 독립 PP들은 콘텐츠 제작 및 구매도 어려운 환경에 놓여 있으며, 지상파 재방 콘텐츠에 의존하는 등 제작보다는 유통에 치중하고 있는 실정이었다. 이는 PP시장의 불균형을 심화시키고, 궁극적으로는 한국의 콘텐츠 산업의 발전에 부정적인 결과를 초래하게 된다. 따라서 독립 PP의 위상을 높이기 위한 방안이 강구되어야 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권1호
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• pp.102-122
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• 2017

Nanotechnology has provided a set of tools that the engineers can use to design and manufacture integrated nano devices, which are capable of performing sensing, computing, data storing and actuation. One of the main hurdles for nano devices has been the amount of power that it can generate for transmission of data. In this paper, we proposed cooperative nano communication in the Terahertz (THz) Gap frequency band to increase the range of transmission. Outage probability (OP) performances for the proposed cooperative nano communication networks in the THz band (0.1 - 10THz) have been evaluated for the following scenarios; A) A single decode-and-forward (DF) relay over independent identically distributed (i.i.d.) Rayleigh fading channels, B) DF multi-relay network with best relay selection (BRS) over i.i.d. Rayleigh fading channels, and C) DF multi-relay network with multiple hops with BRS over i.i.d. Rayleigh fading channels. The results show that the transmission distance can be improved significantly by employing DF relays. Also, it is shown that by increasing the number of hops in a relay the OP performance is marginally degraded. The analytical results have been verified by Monte-Carlo simulation.