• Journal of Internet Computing and Services
• /
• v.17 no.1
• /
• pp.83-89
• /
• 2016

This study aimed to examine how gender and regional differences affect the relationships between SNS use and social capital. By analyzing a large set of data from Korean teenagers, significant roles of gender and regional differences could be found. In regards to gender difference, the most notable finding was the negative effects of SNS use on bonding and bridging social capital among male teenagers. Furthermore, it was found that such negative effects of SNS use were significant particularly among urban teenagers. These findings theoretically contribute to broadening the understanding of the relationships between SNS use and social capital.

• The Korean Journal of Ceramics
• /
• v.5 no.2
• /
• pp.178-182
• /
• 1999

Simple binary $Na_2S-SiO_2$ oxysulfide glasses were prepared by a conventional melt-quench method in order to investigate the role of sulfur in glass structure and the electronic state. By X-ray photoelectron spectroscopy(XPS) measurement, S2p binding energy of the glass was observed at approximately 161eV which was close to that of ionic $S^{2-}$. The coordinating state around silicon atoms were investigated by ${29}^Si$ MAS-NMR measurement. The chemical shift observed from NMR supported that sulfur atom was joined to a silicon atom by substituting for an oxygen atom and was present as a non-bridging sulfide ion in low alkali content. On the other hand, it could be presumed that a portion of sulfur anions existed in an isolated state from the glass-network frame at high alkali content. The state of these sulfurs was also studied by Raman spectroscopy in detail.

• The Journal of Asian Finance, Economics and Business
• /
• v.9 no.5
• /
• pp.421-429
• /
• 2022

Entrepreneurship research has focused on several factors that might affect the intention of an individual to start an enterprise. Using principles from social network theory and the entrepreneurial intention model (EI), the current research intends to investigate how social capital is formed on Social Networking Sites (SNS) and how the resulting social capital influences entrepreneurial intention. Using an online survey, 151 valid responses were received from university students. Applying partial least square structural equation modeling, positive and significant relationship was found between the SNS usage and bonding and bridging social capital. Further, it was also found that online-bonding social capital does not impact any of the three antecedents of entrepreneurial intention. On the other hand, online-bridging social capital significantly influences personal attitudes and subjective norms. It was also found that both personal attitude and perceived behavioral control significantly relate to EI, while the subjective norms do not relate significantly to EI. The paper contributes to the literature on technology-based human behavior and entrepreneurship in emerging countries, opening some areas for future research, while also providing some managerial insights. It also should be beneficial to educational institutions in understanding how the use of SNS use by students may be optimized.

• Journal of the Korean Ceramic Society
• /
• v.34 no.8
• /
• pp.870-876
• /
• 1997

Ge-Ga-S glasses, contrary to other well-known chalcogenide glasses, show high rare-earth solubility. Raman spectra of GeS2-Ga2S3 glasses showed that two peaks at 260 cm-1 and 385 cm-1 increased in intensity with the addition of Ga2S3. These peaks are associated with the vibration of Ge-Ge bonds and edge-shared [GsS4] tetrahedra, respectively. In GeS2-Ga2S3-La2S3 glasses, the peak at 260 cm-1 decreased in intensity with addition of La2S3 and the one at 375 cm-1 due to the vibration of tetrahedra with non-bridging sulfurs increased. It indicated that La, or rare-earths in general, can easily be dissolved into the glass network as charge compensators for non-bridging sulfurs which were formed through the dissociation of Ge-Ge bonds and edge-shared [GaS4] tetrahedra. Since no such structural modification is expected in glasses as Ga-As-S, these peculiar transitions on the connection scheme in Ga-containing chalcogenide glasses seem to be playing the most important role on the enhanced rare-earth solubility.

• Nuclear Engineering and Technology
• /
• v.53 no.12
• /
• pp.4106-4113
• /
• 2021

Rare earth doped barium tellurite glasses were synthesised and explored for their radiation shielding applications. All the samples showed good thermal stability with values varying between 101 ℃ and 135 ℃ based on dopants. Structural properties showed the dominance of matrix elements compared to rare earth dopants in forming the bridging and non-bridging atoms in the network. Bandgap values varied between 3.30 and 4.05 eV which was found to be monotonic with respective rare earth dopants indicating their modification effect in the network. Various radiation shielding parameters like linear attenuation coefficient, mean free path and half value layer were calculated and each showed the effect of doping. For all samples, LAC values decreased with increase in energy and is attributed to photoelectric mechanism. Thulium doped glasses showed the highest value of 1.18 cm^-1 at 0.245 MeV for 2 mol.% doping, which decreased in the order of erbium, holmium and the base barium tellurite glass, while half value layer and mean free paths showed an opposite trend with least value for 2 mol.% thulium indicating that thulium doped samples are better attenuators compared to undoped and other rare earth doped samples. Studies indicate an increased level of thulium doping in barium tellurite glasses can lead to efficient shielding materials for high energy radiation.

• Journal of the Mineralogical Society of Korea
• /
• v.22 no.4
• /
• pp.343-352
• /
• 2009

High-resolution Solid-state NMR provides element specific and quantitative information and also resolves, otherwise overlapping atomic configurations in multi-component non-crystalline silicates. Here we report the preliminary results on the effect of composition on the structure of CMAS (CaO-MgO-$Al_2O_3-SiO_2$) silicate glasses, as a model system for basaltic magmas, using the high-resolution 1D and 2D solid-state NMR. The $^{27}Al$ MAS NMR spectra for the CMAS silicate glasses show that four-coordinated Al is predominant, demonstrating that $Al^{3+}$ is network forming cation. The peak position moves toward lower frequency about 4.7 ppm with increasing $X_{MgO}$ due to an increase in $Q^4$(4Si) fraction with increasing Si content, indicating that Al are surrounded only by bridging oxygen. $^{17}O$ MAS NMR spectra for $CaAl_2SiO_6$ and $CaMgSi_2O_6$ glasses qualitatively suggest that NBO fraction in the former is smaller than that in $CaMgSi_2O_6$ glasses. As $^{17}O$ 3QMAS NMR spectrum of model quaternary aluminosilicate glass resolved distinct bridging and non-bridging oxygen environments, atomic structure for natural magmas can also be potentially probed using high-resolution 3QMAS NMR.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.1
• /
• pp.1-8
• /
• 1997

A wide class of networking application services, such as video teleconferencing, VOD, LAN bridging, and distributed data processing require multipoint communications. The essential component inteh network to achieve this is a multicast packet switch which is capable of packet replication and switching. In this paper, we propose an efficient mukticast addressing scheme using the smallest number of routing bits which is deterministic lower bound. The new scheme performs all point-to-multipoint connection in radix-2 tree ATM switch like banyan network. Also, we provide a simple radix-2 switch block diagram for achieving our algorithm. And we investigate several addressing schemes for implementing multicasting in radix-r tree ATM switch and evaluate several performance factors, such as complexity of the additional header bits, requirement of the internal speedup and complexity of the major hardware.

• Proceedings of the KAIS Fall Conference
• /
• 2006.05a
• /
• pp.294-297
• /
• 2006

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05a
• /
• pp.138-141
• /
• 2010

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• International Journal of Advanced Culture Technology
• /
• v.11 no.1
• /
• pp.395-402
• /
• 2023

The implementation of a hybrid network utilizing Power Line Communication (PLC) and Wi-Fi technologies has been demonstrated to improve signal strength and coverage in areas with poor connectivity due to internet shadow areas. In this study we strategically positioned Wi-Fi relays and utilized the capabilities of PLC technology to significantly improve signal strength and coverage in areas with poor connectivity. We also analyzed the effects of metallic obstacles on Wi-Fi signal propagation and proposed a solution to strengthen the signal enough to pass through them. Our experiment demonstrated the feasibility and potential of using this hybrid network in industrial scenarios for real-time data transmission. Overall, the results suggest that the use of PLC and Wi-Fi hybrid networks can be a cost-effective and efficient solution for overcoming internet connectivity challenges and has the potential to provide high-speed internet access to areas with unreliable signals.