• Journal of Korean Library and Information Science Society
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• v.38 no.3
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• pp.73-90
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• 2007

The Pareto principle, also known as the 80/20 rule, describes this common pattern of sales concentration. But long tail principle, that expose the power of majority which had been put aside for a long time, rise as a new business strategy in web 2.0 era. In digital and online environment, as created the conditions that satisfy the need of diversity, long-tail effect has been relevant to all social cultures. This paper consider the long-tail effect from a library service point of view and develop library's long-tail strategies. For the more, suggest practical plan about library long-tail based on library 2.0.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.99-111
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• 2024

Purpose - This study aims to quantify the long tail effect in the digital economy. It also investigates the role of digital platform before and after the COVID-19 pandemic. Design/methodology/approach - We take advantage of a granular data set from one of the biggest digital platforms in Korea. Rather than computing the absolute number of products sold or the Gini coefficient, we estimate the slope of the log-linear relationship of the non-parametric sales distribution. Findings - We find that the use of online food order and delivery services is positively associated with individual restaurant's sales growth. We also document that the long tail effect is increasing over time. Long tail effects are clustered in the cross-section where average revenue per order is high or the restaurant belongs to the top 50% of the sales distribution. Research implications or Originality - The findings may indicate that digital platforms are contributing to the development of the digital economy in Korea. Also, we confirm that digital platforms make it possible for small and sole proprietors to go through the difficulties induced by the COVID-19 pandemic.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.265-281
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• 2017

For shallow tunnel constructions, settlement of the ground surface is a main issue. Recent technical developments in shield TBM tunneling technique have enabled a decrease in such settlements based on tunneling with ground deformation controls. For this objective, the tail void grouting is a common practice. Generally surface settlements in a soil of low permeability occur during a tunnel construction but also during a long period after completion of the tunnel. The long-term settlements occur mainly due to consolidation around the tunnel. The consolidation process is caused and determined by the tail void grouting which leads to an excess pore water pressure in the vicinity of the tunnel. Because of this, the grouting pressure has a strong effect on the long-term settlements in the shield tunneling. In order to investigate this effect, a series of coupled hydro-mechanical 3D finite element simulations have been performed. The results show that an increase in grouting pressure reduces the short-term settlements, but in many cases, it doesn't lead to a reduction of the final settlements after the completion of consolidation. Thereby, the existence of a critical grouting pressure is identified, at which the minimal settlements are expected.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.69-78
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• 2021

With technological development including digitization, movie demand and supply in digital online movie market are increasing. This study aims to explore demand concentration of the digital online movie market, which is characterized by product variety compared to cinemas. Major findings of the empirical analysis on the TV VOD data during the recent seven years(2013 ~ 2019) are as follows. First, the analysis on 1,137 titles reveals that movie demand of theatrical market is more concentrated than that of TV VOD. Second, absolute long tail index of TV VOD, measured by the download number of indie & artistic movies(niche product), is increasing as more such movies are released in the market. However, both relative long tail index, measured by the share of indie & artistic movie demand, and top-ranked movies' share do not show consistent increase or decrease trend. Third, regression analysis exhibits that the relationship between demand concentration and market size is insignificant for TV VOD market. This study might have usefulness in that it provides empirical evidence for the nature of the Korean digital online movie market.

• Information Systems Review
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• v.24 no.2
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• pp.1-20
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• 2022

Researchers are making contradictory claims through the concept of superstars and long tails about how the development of IT technology affects demand distribution. Unlike previous studies that focused on changes in demand from a macro point of view, this study explored whether the relationship between a company's marketing activities and consumer response differs depending on the product location (i.e., superstar vs. long tail) from a micro point of view. Based on the marketing mix framework, hypotheses were developed based on the relevant literature. In the case of empirical analysis, 2,835 daily data from 63 Korean films were tested using the quantile regression method. As a result of the analysis, it was found that the influence of marketing mix factors on sales varies depending on the location of the product. Specifically, the appeal breadth of the film and the effect of owned media are enhanced in superstar products, and the effect of acquisition media in long-tail products is enhanced and the negative effects of competition are mitigated. Unlike previous studies that focused on macroscopic changes in demand distribution, this study suggested marketing activities suitable for practitioners through microscopic analysis.

• Journal of Nutrition and Health
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• v.43 no.6
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• pp.570-577
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• 2010

Water gets magnetically charged when it is contacted with a magnet. Although magnetic water products have been promoted since the 1930's, they have received very little recognition due to questionable effectiveness. Diethylnitrosamine (DEN) is a widely occurring nitrosamine that is one of the most important environmental carcinogens primarily inducing tumors of liver. In this study, the effect of magnetized water supplementation on lymphocyte DNA damage in ICR mice treated with DEN was evaluated using the Comet assay. Mice were divided into 3 groups: control, DEN, and DEN + magnetized water group. Fifteen mice were maintained in each group for the entire experimental period of 6, 12 and 18 weeks. Five mice in each group were sacrificed at 6, 12, and 18th weeks, followed by the Comet assay using the blood obtained from heart puncture of the mice. The level of lymphocyte DNA damage reflected by tail moment and other DNA damage indices of tail DNA (%) or tail length of the magnetized water group were significantly decreased after the 6th, 12th and 18th weeks of supplementation compared with the positive control, the DEN group. The relative DNA damage of the magnetized water groups compared to the DEN control group after 6th, 12th, and 18th weeks of supplementation were 42.2%, 40.8%, and 32.9% for DNA in tail, 31.2%, 32.6%, and 21.3% for tail length, and 33.8%, 33.8%, and 24.6% for tail moment, respectively. This is the first report demonstrating that magnetized water may be involved in the lowering effect of the DNA damage in DEN-treated ICR mice. This result suggests that the magnetized water might have minimized the DNA damage by improving the antioxidant status of the mice. However, further studies are needed to characterize the condition of the magnetization and examine the long-term effect of the water product.

• YAKHAK HOEJI
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• v.48 no.3
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• pp.177-181
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• 2004

Non-invasive blood glucose measurement from mouse tail was performed by near-infrared (NIR) spectroscopy. Three groups; normal, type I diabetes (insulin dependent diabetes mellitus, IDDM), type II diabetes (non-insulin dependent diabetes mellitus, NIDDM) group, were studied over a 10 weeks period with the collection of near-infrared (NIR) spectra. Spectral variations from long-term measurement (10 weeks) from dramatic and nonlinear changes in the optical properties of the live tissue sample were compensated by chemometrics techniques such as principle component analysis (PCA) and partial least squares (PLS) regression. The effect from mouse body temperature changes on NIR spectral data was also considered. This study showed that the compensation of variations from long-term measurement and temperature changes improved calibration accuracy of non-invasive blood glucose measurement.

• Ocean and Polar Research
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• v.40 no.3
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• pp.161-167
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• 2018

We examined the effect of salinity and water temperature on hatching and survival rates of fertilized eggs of hybrid grouper (Epinephelus fuscoguttatus ♀ ${\times}$ E. lanceolatus ♂) at different developmental stages, determining optimal conditions for their long-distance transportation. Deformities and hatching rates of fertilized grouper eggs were observed at salinities of 24, 27, 30, 33, 36, and 39 psu. The optimal salinity was determined to be 36 psu, with a survival rate of $70.0{\pm}2.0%$. Transportation experiments at 36 psu were conducted at water temperatures of 21, 24, 27, and $30^{\circ}C$, different developmental stages such as morula, 5-myomere, and tail beating for hatching and survival rates. The optimal water temperature and developmental stage for transporatation were $30^{\circ}C$ and tail beating stage and those hatching rates were $50.6{\pm}1.9%$ and $86.3{\pm}1.3%$, respectively. At $21^{\circ}C$, the survival rate by transportation water temperature was highest ($73.1{\pm}10.6%$), but the hatching rate ($17.1{\pm}3.1%$) was lowest. Therefore, the hybrid grouper fertilized eggs (E. fuscoguttatus ♀ ${\times}$ E. lanceolatus ♂) can be most efficiently produced under long-distance transportation conditions during the tail beating stage and at a water temperature of $30^{\circ}C$.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.203-221
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• 2019

How has the use of academic journals changed since the academic library purchase policy changed from selective journals based on core journals to package purchases by big deal? The purpose of this study is to analyze the effect of supply and size of academic journals in university libraries on the use of journals. For this purpose, this study used the actual usage statistics of e-journals of K Academic Libraries during 2013-2015. The analysis shows that there is a so-called long-tail shape in which demand shifts to niche products that are effective in online platforms. Analysis of the use of academic journals by year for three years showed that the use of electronic journals in K Academic Libraries appeared to be a perfect Pareto shape, which is concentrated in the top 20% of journals. In particular, in 2015, the top 5% of journals accounted for nearly 80% of the total usage. Despite the changes in the supply method and size of academic journals, users' use of journals was still concentrated in core journals.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.483-492
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• 2014

DNA damage such as genotoxicity was identified with comet assay, which blood cell of a marine parrot fish (Oplegnathus fasciatus) was exposed to an acidified seawater, lowered pH gradient making of $CO_2$ gas. The gradient of pH were 8.22, 8.03, 7.81, 7.55 with control as HBSS solution with pH 7.4. DNA tail moment of fish blood cell was $0.548{\pm}0.071$ exposed seawater of pH 8.22 condition, on the other hand, DNA tail moment $1.601{\pm}0.197$ exposed acidified seawater of pH 7.55 lowest condition. The approximate difference with level of DNA damage was 2.9 times between highest and lowest of pH. DNA damage with decreasing pH was significantly increased with DNA tail moment on blood cell of marine fish (ANOVA, p < 0.001). Ocean acidification, especially inducing the leakage of sequestered $CO_2$ in geological structure is a consequence from the burning of fossil fuels, and long term effects on marine habitats and organisms are not fully investigated. The physiological effects on adult fish species are even less known. This result shown that the potential of dissolved $CO_2$ in seawater was revealed to induce the toxic effect on genotoxicity such as DNA breakage.