• The Korean Journal of Physiology and Pharmacology
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• v.24 no.1
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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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• v.59 no.4
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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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.447-450
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• 2009

In this paper, binary pulse-antipodal modulation (2PAM) direct-sequence (DS) ultra-wideband (UWB) system is applied to multiple input multiple output (MIMO) system using vertical bell lab layered space-time (V-BLAST) structure to achieve high-data-rate communications over indoor wireless channels. The relationship between antenna dimension and BER performance of 2PAM DS UWB MIMO system is discussed. In the receiver of UWB-MIMO system, various MIMO detection algorithms such as zero-forcing (ZF), ZF-ordered successive interference cancellation (OSIC), minimum-mean-square-error (MMSE), MMSE-OSIC and maximum likelihood (ML) are comparatively studied.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.581-586
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• 2010

MC-DS-CDMA is technique where a single data symbol is transmitted at multiple subcarriers which are orthogonal to each other. With this technique, frequency diversity can be achieved. Time variant channels lead to interchannel interference which increases the bit error rate for MC-DS-CDMA systems. The performance of PSAM MC-DS-CDMA system over time variant channels is analyzed. The BER performance of this system over multipath fading environment is evaluated, considering the channel estimation error, carrier frequency offset.

• Smart Structures and Systems
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• v.16 no.4
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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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• 2008.05a
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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.

• Journal of Distribution Science
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• v.16 no.5
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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.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.34-37
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• 2017

This letter presents the signal processing of a CW radar (Continuous Wave or Doppler radar) sensor which enables the radar to detect the multiple targets' approaching and retreating using both I and Q channels. The proposed algorithm utilizes the phase change of the Quadrature signal, which occurs when targets move back and forth from the radar. The verification is carried out with the board containing a commercially available MMIC chip and an MCU by analyzing the received data from MMIC. Also the proposed algorithm is downloaded to MCU and the approaching and retreating movement is confirmed. The CW frequency is 24.125 GHz and the transmitter output power used is 7.2 dBm. Detectable distance is about 12 m.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.71-80
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• 2013

This study addressed status of PP(Program Provider) market, particularly focusing on independent PP. This research selected 14 independent channels and did in depth interviews for them. This study analyzed 14 channels in terms of management, production, and contents. The result showed that independent channels were in inferior condition than MPP(multiple PP) on all the aspects of management, production and content. The management structure of the PP were very vulnerable, production environment was not good. The PP were placed in a difficult environment in terms of production and purchases of content, therefore focused on distribution rather than production. This unbalance on the PP market resulted in negative effect on Korea's contents industry as well as PP industry. Therefore, this study suggested policy and regulatory reforms are needed to improve inferior status of independent PP.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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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.