• Asia Marketing Journal
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• v.17 no.1
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• pp.69-95
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• 2015

This paper examines a highly used social networking site (SNS) by studying the behavior of more than 11 million members over a 20 month period. The importance of the most highly active members to the overall network is demonstrated by the significant fraction of total visits by extremely active members in a given period but such members have surprisingly short lifespans (an average of only 2.5 months) as social hubs. We form and test a number of hypotheses concerning these social hubs and the determinants of their lifespan. We find that the speed of achieving social hub status increases the lifespan of a social hub. The norm of reciprocity is strongly confirmed to be present in the social hub population as visits are reciprocated. We also find that increasing local dominance in terms of activities over neighboring agents leads to a longer lifespan of a social hub. Contrary to expectations, local clustering in the vicinity of social hubs is smaller (rather than larger) than overall clustering. We discuss managerial implications in the paper.

• Journal of Korea Entertainment Industry Association
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• v.14 no.3
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• pp.411-419
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• 2020

With the increasing number of skin care shops, service quality development that can meet the customer needs is needed to obtain differentiated competitive advantage. Accordingly this study was attempted to provide basic data on marketing necessary for operating a skin care shop by identifying the impact of service quality on perceived reciprocity and long-term relationship orientation among the customers using a skin care shop. This study conducted a survey of 290 female customers using skin care shops located in Seoul and Gyeonggi province, Jeollanamdo and Jeollabukdo, and Gyeongsangnamdo and Gyeongsangbukdo through personal visit, e-mail, and post service, and the collected data were analyzed with SPSS Ver. 18.0 and Amos Ver. 18.0. As a result, it was proven that overall goodness-of-fit to the theoretical model of the research hypotheses set in this study is good. In Hypothesis 1, "Skin care specialist's work ability, facility and sanitation, and care products had a significant positive (+) impact on perceived reciprocity," which was partially adopted. In Hypothesis 2, "Skin care specialist's work ability, care products, and devices and tools had a significant positive (+) impact on long-term relationship orientation," which was adopted. In Hypothesis 3, "Perceived reciprocity had a significant positive (+) impact on long-term relationship orientation," which was adopted. Therefore, it can be concluded that skin care specialist's work ability, facility and sanitation, care products, and devices and tools are the service quality elements for allowing customers to feel thankful or encouraging them to visit the skin care shops continuously.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.524-539
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• 2014

To investigate schemes of secret key generation from Ultra-wideband (UWB) channel, we study a statistical characterization of UWB outdoor channel for a campus playground scenario based on extensive measurements. Moreover, an efficient secret key generation mechanism exploiting multipath relative delay is developed, and verification of this algorithm is conducted in UWB Line-of-sight (LOS) outdoor channels. For the first time, we compare key-mismatch probability of UWB indoor and outdoor environments. Simulation results demonstrate that the number of multipath proportionally affects key generation rate and key-mismatch probability. In comparison to the conventional method using received signal strength (RSS) as a common random source, our mechanism achieves better performance in terms of common secret bit generation. Simultaneously, security analysis indicates that the proposed scheme can still guarantee security even in the sparse outdoor physical environment free of many reflectors.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.158-164
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• 1999

In this paper a simple measurement technique for mechanical-acoustic transfer functions is proposed . The mechanical-acoustic transfer functions, generally , are measured through mechanical excitations ; impact hammers or shakers. Recently , by virtue of vibro-acoustical reciprocity principle, they are measured through acoustic excitations : loudspeakers. This kind of test needs to measure the volume velocity , the radiation characteristics of a sound source. Because the volume velocity of the sound source is changed by driving signal , it is difficult to measure it. However , the new method in this paper needs not to measure the volume velocity of a sound source by combination of mechanical and acoustic excitations. Moreover, this method has the methodological advantages, such as usage of a general loudspeaker for the reciprocal excitation, no sptatial limitations for measurements of mechanical-acoustic transfer functions.

• Journal of the Korean Home Economics Association
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• v.42 no.11
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• pp.1-15
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• 2004

This study examined the interaction between children's peer experiences and familial support in relation to their psychosocial adjustment(self-esteem and lonelitness). Peer experiences were examined in terms of children's perceptions of peer acceptance and the reciprocity of best friendship. The subjects were 2754th or 5th graders residing in Seoul. It was found that the interaction between children's perceptions of peer acceptance and familial support, and that between the reciprocity of bort friendship and familial support were both significant predictors of children's loneliness whereas only the former was a significant predictor of children's self-esteem. The study results suggest that children's experiences from one type of interpersonal relationship should be examined in conjunction with their experiences in other types of relationships in order to better understand the psychosocial domains of child development.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.159-166
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• 2002

Today print media survives in tough struggle for existence and is deep to development of new technology as well as edit style and manufacture environment improvement that utilize actively a computer to establish new phase, and Desk Top Publishing or information industry department and link development are required. Propose analysis and solution way that this paper is examining concept of electronic publishing and manufacture progress, and analyze reciprocity degree of electronic publishing process through active and cluster analysis, and electronic publishing knows.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.501-506
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• 2007

Structure-borne noise is the interior noise that results from the low frequency vibrational energy transmitted through those body and joint parts. The relation between the excitation of powertrain and resultant interior sound must be analyzed in order to identify and predict the structure borne noise. The method of acoustic source excitation is preferred than the method of mechanical force excitation to measure the NTF(noise transfer function). Because acoustical method is more convenient and reliable. In this paper, to analysis and identify vehicle interior noise by powertrain is performed, and the vibro-acoustic transfer function is extracted from experimental measurement. These are important step of TPA(transfer path analysis) to identify effect of interior noise resulted from powertrain running excitation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3557-3571
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• 2014

We develop a secret key generation scheme using phase estimation in ultra-wideband (UWB) wireless fading channels. Based on the reciprocity theorem, two terminals extract the phase of the channel as a common random source to generate secret bits. Moreover, we study the secret key rate by a pair of nodes observing correlated sources and communicating to achieve secret key agreement over public communication channels. As our main results, we establish a more practical upper bound from Cramer-Rao bound (CRB) and compare it with a universally theoretical upper bound on the shared maximum key rate from mutual information of correlated random sources. Derivation and numerical examples are presented to demonstrate the bound. Simulation studies are also provided to validate feasibility and efficiency of the proposed scheme.

• Knowledge Management Research
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• v.12 no.2
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• pp.1-16
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• 2011

This study examined the influence of the antecedents of knowledge transfer from both the knowledge source's and recipient's perspectives using a social network survey. Prior research usually focused on either perspective of the knowledge source or recipient, thus could not include both. Analyzing the responses from 335 R&D employees of the five firms, the study showed that all antecedents of knowledge transfer - reward, reciprocity, subjective norm, and perceived behavioral control - are influential on knowledge transfer from the knowledge source's perspective. However, from the knowledge recipient's perspective, perceived behavioral control was influential on the quality of knowledge transfer and subjective norm was on the number of knowledge recipients. Expected reward and reciprocity did not show significant influence. This study proved that the necessity of considering both the knowledge source's and the recipient's perspectives when measuring knowledge transfer and the importance of intrinsic motivations, such as subjective norm and perceived behavioral control.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.398-400
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• 2006

The symplectic form based on a symplectic space is introduced to simplify a probe compensation equation in terms of the near-field measurement algorithm. The Lorentz reciprocity principle is also utilized for a near-field probe compensation equation. Applying the symplectic form to the probe compensation equation gives a simplified probe equation, thus confirming the validity of our approach.