• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.222-224
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• 1996

This paper treats the stream phenomena of high frequency current on the solid-loop coil of which consists the hollow conductor. The governing equation is derived from electromagnetic field theory and the characteristics are analyzed by FEM with 2-D and 3-D. The results may be available data on designing the optimum shape of the coil for the improved pinch effect.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.127-133
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• 2009

With advances in video technology, many researchers are interested in video quality assessment to prove better performance of proposed algorithms. Since human visual system is too complex to be formulated exactly, many researches about video quality assessment are in progressing. No-reference video-quality assessment is suitable for various video streaming services, because of no requested additional data and network capacity to perform quality assessment. In this paper, we propose a novel no-reference video-quality assessment method with the estimation of dynamic range distortion. To measure the performance, we obtain mean opinion score (MOS) data by subject video quality test with the ITU-T P.910 Absolute Category Rating (ACR) method. And, we compare it with proposed algorithm using 363 video sequences. Experimental results show that the proposed algorithm has a higher correlation with obtained MOS.

• The Korean Journal of Ecology
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• v.25 no.1
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• pp.63-70
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• 2002

This study examined the changes of water quality in relation to distribution of hydrophytes, and the purification capacity of Zizania latifolia to improve the effluent from Munpyeong stream from March 1997 to December 1999. While the concentration of nitrogen and phosphorous in water were increased during the farming season, those decreased, during the streaming down to paddy and drainage areas. In investigated sites, the Z. latifolia was dominant community according to the development of the natural wetlands. Furthermore, it formed a large community owing to its high adaptability to environmental changes in the agriculture lands. In September, the leaves productivity of the Z. latifolia were 4,032g D.W/$m^2$and roots were 7,680gD.W/$m^2$. The purification capacity of the Z. latifolia for NH$_3$-N, $No_3$-N, and PO$_4$-P were 13.41, 17.07, and 4.58 respectively during 5 days. The results suggested that it needs to establish wetlands vegetated by hydrophytes to improve the water quality of the effluent from agricultural lands.

• Textile Coloration and Finishing
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• v.1 no.1
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• pp.19-25
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• 1989

In past, dye diffusion and dyeing rate in fibers have been emphasized in dyeing phenomena. However, in the light of the properties of colloids in the surface of disperse phase and dispersion, there exist specific characters such as adsorption or electric double layer, which seems to play important roles in determining the physiochemical properties in the dyeing system. Electrostatic bonding, hydrogen bonding and Van der Waals adsorption are common in dyeing as well as covalent bonding. Particularly, electrostatic bonding is premised on the existance of ionic radicals in fibers. The present study was aimed to clarify the electrokinetic phenomena of dyeing through the role of electric double layer by ion in amphoteric fibers with different ionic effects under different pH. Spectrophotometric analysis method was used to compare dyeing condition of surface, which can be detected by electrokinetic phenomena and the inner of fibers after deceleration of dyed fibers. Nylon and wool, the typical amphoteric fibers were dyed with monoazo acid dyes such as C.I. Acid Orange 20, and C.I. Acid Orange 10. Various combinations were prepared by combining pH, temperature and dye concentration, in order to generate streaming electric potential which were measured by microvolt meter and specific conductivity meter. The results were transformed to zeta potential by Helmholtz-Smoluchowski formular and to surface electric charge density by Suzawa formular, surface dye amount, and effective surface area of fibers. The amount of dyes of inner fibers were also measured by the Lambert-Beer’s law. The main results obtained are as follows. 1. By measuring zeta pontential, it was possible to detect the dyeing mechanism, surface charge density, surface dye amount and effective surface area concerning dye adsorption of the amphoteric fibers. 2. Zeta pontential increases in negative at low pH and high dye concentration in the process of dyeing. This implied that there existed ionic bond formation in the dyeing mechanism between acid dyes and amphoteric fibers. 3. Dibasic acid dye had little changing rate in zeta potential due to the difference in solubility of dye and in number of dissociated ions per dye molecule to bond with amino radicals of amphoteric fibers. The dye adsorption of mono basic acid dye was higher than that of dibasic acid dye. 4. The effective surface areas concerning dyeing were $6.3E+05\;cm^2/g$ in nylon, $1.6E+07\;cm^2/g$ in wool fiber being higher order of wool then nylon.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.7-14
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• 2016

This study analyzes popular channels of America's Twitch TV that centers on video game among several Internet broadcasting services. Afreeca TV de facto monopolizes the Internet broadcasting industry in South Korea; however, Twitch TV is popular around the globe and tries to expand business in Korea. Specifically, this study collects data of popular domestic/international channels on every Friday 9:00 p.m. 20 times, and examines differences of between those channels: 1) the number of the audience(users) 2) the frequency of games 3) the genre of games 4) nationality of games. Internet broadcasting streaming service does not have a concept of ratings, but it could be categorized as popular based on users connecting the channels. Thus, this study studies characteristics of Twitch TV, and further discusses the future of the Internet broadcasting.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.629-639
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• 2010

To evaluate the performance of high rate coagulation system(HRCS) for CSOs treatment, fundamental function of lab scale HRCS has been tested by using the Jar tester and lab scale HRCS. The optimum pH dose by Streaming Current value was found in the range of 5.3~6.0 in Fe(III), and in the range of 5.8~6.6 in Al(III) and the optimum chemical dose were 0.44mM of $Al_2(SO_4)_3$ and 0.93mM of $FeCl_3$. The removal efficiencies at optimum $Al_2(SO_4)_3$ dose were 75%($TCOD_{Cr}$), 97%(TP), 95%(SS) and 96%(turbidity), respectively. And the removal efficiency of particles with less than $5{\mu}m$ of diameter was 70% and that of particles with higher than $5{\mu}m$ of diameter was 90%. The optimum alum dose in lab scale HRCS was 150mg/L, and the treatment efficiency was the best with addition of 1.0mg/L polymer. The effect of Micro sand addition was not clear, because the depth of the sediment tank in lab scale HRCS was not long enough. But the HRT of this lab scale HRCS was able to be shorten less then 7 minutes by adding the micro sand. The surface loading rates with respect to using different chemicals were 0.43m/h with alum only, 5.78m/h with alum and polymer and 6.22m/h with alum, polymer and micro sand. As a result, HRCS using coagulant, polymer and micro sand developed in this study was evaluated to be very effective for CSOs treatment.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.97-122
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• 2007

Conventional networking and telecommunications infrastructure characterized by wires, fixed location, and inflexibility is giving way to mobile technologies. Numerous research reports point to the ultimate domination of wireless communication. With the increasing prevalence of advanced cell-phones, various mobile data services (hereafter MDS) are gaining popularity. Although cellular networks were originally introduced for voice communications, statistics indicate that data services are replacing the matured voice service as the growth engine for telecom service providers. For example, SK Telecom, the Korea's largest mobile service provider, reported that 25.6% of revenue and 28.5% of profit came from MDS in 2006 and the share is growing. Statistics also indicate that, in 2006, the average revenue per user (ARPU) for voice didn't change but MDS grew seven percents from the previous year, further highlighting its growth potential. MDS is defined "as an assortment of digital data services that can be accessed using a mobile device over a wide geographic area." A variety of MDS have been deployed, with a few reaching the status of killer applications. Many of them need to access the Internet through the cellular-phone infrastructure. In the past, when the cellular network didn't have acceptable bandwidth for data services, SMS (short messaging service) dominated MDS. Now, Internet-ready, next-generation cell-phones are driving rich digital data services into the fabric of everyday life, These include news on various topics, Internet search, mapping and location-based information, mobile banking and gaming, downloading (i.e., screen savers), multimedia streaming, and various communication services (i.e., email, short messaging, messenger, and chaffing). The huge economic stake MDS has on its stakeholders warrants focused research to understand associated dynamics behind its adoption. Lyytinen and Yoo(2002) pointed out the limitation of traditional adoption models in explaining the rapid diffusion of innovations such as P2P or mobile services. Also, despite the increasing popularity of MDS, unexpected drop in its usage is observed among some people. Intrigued by these observations, an exploratory study was conducted to examine decision factors of MDS usage. Data analysis revealed that the increase and decrease of MDS use was influenced by different forces. The findings of the exploratory study triggered our confirmatory research effort to validate the uni-directionality of studied factors in affecting MDS usage. This differs from extant studies of IS/IT adoption that are largely grounded on the assumption of bi-directionality of explanatory variables in determining the level of dependent variables (i.e., user satisfaction, service usage). The research goal is, therefore, to examine if increase and decrease in the usage of MDS are explained by two separate groups of variables pertaining to information quality and system quality. For this, we investigate following research questions: (1) Does the information quality of MDS increase service usage?; (2) Does the system quality of MDS decrease service usage?; and (3) Does user motivation for subscribing MDS moderate the effect information and system quality have on service usage? The research questions and subsequent analysis are grounded on the two factor theory pioneered by Hertzberg et al(1959). To answer the research questions, in the first, an exploratory study based on 378 survey responses was conducted to learn about important decision factors of MDS usage. It revealed discrepancy between the influencing forces of usage increase and those of usage decrease. Based on the findings from the exploratory study and the two-factor theory, we postulated information quality as the motivator and system quality as the de-motivator (or hygiene) of MDS. Then, a confirmative study was undertaken on their respective role in encouraging and discouraging the usage of mobile data service.