• Korean Journal of Optics and Photonics
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• v.35 no.2
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• pp.49-60
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• 2024

We analyze the number of phase screens required for the simulation of a high-energy laser beam's propagation over an atmospheric channel. For high-energy lasers exceeding tens of kilowatts (kW) in power, the laser beam is mainly affected by atmospheric turbulence and thermal blooming. When using the split-step method to implement losses due to atmospheric absorption and scattering and distortion of the beam due to turbulence and thermal blooming, the number of phase screens is a critical factor in determining the accuracy and time required for the simulation. By comparing simulation results obtained using a large number of phase screens (e.g., 150 screens) under a wide range of atmospheric turbulence conditions, we provide new guidelines for the number of phase screens required for simulating the beam propagation of a high-power laser below 2.5×10⁶ W/m² (e.g., a 500-kW laser beam having a 50-cm diameter).

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.1-6
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• 2008

The output of the Stirling engine is influenced by the regenerator effectiveness. The regenerator effectiveness is influenced by heat transfer and flow friction loss of the regenerator matrix. In this paper, in order to provide basic data for the design of regenerator matrix, characteristics of flow friction loss were investigated by a packed method of matrix in the oscillating flow as the same condition of operation in a Stirling engine. As matrices, two different wire screens were used. The results are summarized as follows; 1. With the wire screen of No. 50 as regenerator matrices, pressure drop of working fluid of the oscillating flow is shown as 3 times higher than that of one directional flow, not too much influenced by the number of packed meshes. 2. With the wire screen of No. 100 as regenerator matrices, pressure drop of working fluid of the oscillating flow is shown as 2.5 times on the average higher than that of one directional flow, not too much influenced by the number of packed meshes. 3. Under one directional flow which used regenerator matrices with both 200, 240, and 280 wire screens of No. 50 and 320, 370, and 420 wire screens of No. 100, the relationship between the friction factor and Reynold No. is shown as the following formula. $$f=\frac{0.00326639}{Re\iota}-1.29106{\times}10^{-4}$$ 4. Under oscillating flow which used regenerator matrices with both 200, 240, and 280 wire screens of No. 50 and 320, 370, and 420 wire screens of No. 100, the relationship between the friction factor and Reynold No. is shown as the following formula. $$f_r=\frac{0.000918567}{Re\iota}+1.86101{\times}10^{-5}$$ 5. The pressure drop is shown as high in proportion as the number of meshes has been higher, and the number of packed wire screens as matrices increases.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05c
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• pp.61-64
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• 2009

The number of apartment houses has accounted for more than 50% of all domestic residential types in Korea since 1980s. However, the apartment house has environmentally disadvantageous conditions such as highly residential-density and potential falls by children aged seven years and under through windows. In this study, we aim to suggest some ideas to improve domestic performance assessment methods and criteria of window Insect screens for protection on security and fall prevention by analyzing domestic standard with several overseas codes related to the screens for windows.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.950-962
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• 2015

This paper analyzes the effect of the number of viewers and the number of running screens in the theater, genres of the movies and holdback period on the number of purchases movie VOD contents. In this paper, we deals with the 169 movies VOD consumption data which the digital cable TV subscribers purchased during the third quarter of 2013. As a result of the research, the average number of VOD purchases per each movie is 2,540. Regression analysis proves that the number of running screens and the holdback period are statistically playing a role of significance in movie VOD purchases. But the number of viewers in the theaters is not of significance. By genres, the result is shown as in this order: SF/fantasy 8,401 > dramas 4,011 > comedies 2,011 > action 1,789 > animation 1,138 > love story/melo 1,119 > horror/thriller 770 > erotic movies 636.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.274-281
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• 2020

The use of information systems improves a company's service quality and provides efficient information management. The establishment of an information system has become an essential element. In designing and developing a large number of screens when building an information system, As the number of screens increases, so does the cost and time. In addition, modifications can increase the cost of maintenance and exceed the cost of development. In order to solve these problems, there have been studies to design the screen simply and easily, but there is a shortage in reducing the maintenance cost. In this paper, we have studied the layout algorithm for managing the attributes of the screen components as data structures based on the designed screen and arranging the components on the screen. And we compared the proposed method and the methods that have been studied in the related studies. Screen component layout methods can automatically deploy screen components to consistently develop a large number of screens and reduce cost and manpower by reducing the time it takes to deploy screens.

• Journal of radiological science and technology
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• v.5 no.1
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• pp.45-47
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• 1982

Authors carried out the research on the actual condition of intensifying screens in a certain hospital and obtained the results as follows: 1. High speed intensifying screens were 63.9% and medium typed screen had 36.1%. 2. Half the number of using screens(51.5%) were not clear in a period of used time. 3. 47.4% of same typed screens showed a remarkable difference(two times) in sensitivity.

• Asia-Pacific Journal of Business
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• v.12 no.3
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• pp.51-69
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• 2021

Purpose - Based on literature studies of movie reviews and movie ratings, this study raised two research questions on the contents of online word of mouth and the number of movie screens as mediator variables. Research question 1 wanted to figure out which topics of word groups had a positive or negative impact on movie ratings. Research question 2 tried to identify the role of the number of movie screens between movie ratings and box office outcomes. Design/methodology/approach - Through R program, this study collected about 82,000 movie reviews and movie ratings posted on Naver's movie website to examine the role of online word of mouths and movie screen counts in 10 movies that were considered commercially unsuccessful with fewer than 2 million viewers despite securing about 1,000 movie screens. To confirm research question 1, topic modeling, a text mining technique, was conducted on movie reviews. In addition, this study linked the movie ratings posted on Naver with information of KOBIS by date, to identify the research question 2. Findings - Through topic modeling, 5 topics were identified. Topics found in this study were largely organized into two groups, the content of the movie (topic 1, 2, 3) and the evaluation of the movie (topics 4, 5). When analyzing the relationship between movie reviews and movie ratings with 5 mediators identified in topic modeling to probe research question 1, the topic word groups related to topic 2, 3 and 5 appeared having a negative effect on the netizen's movie ratings. In addition, by connecting two secondary data by date, analysis for research question 2 was implemented. The outcomes showed that the causal relationship between movie ratings and audience numbers was mediated by the number of movie screens. Research implications or Originality - The results suggested that the information presented in text format was harder to quantify than the information provided in scores, but if content information could be digitalized through text mining techniques, it could become variable and be analyzed to identify causality with other variables. The outcomes in research question 2 showed that movie ratings had a direct impact on the number of viewers, but also had indirect effects through changes in the number of movie screens. An interesting point is that the direct effect of movie ratings on the number of viewers is found in most American films released in Korea.

• Cartoon and Animation Studies
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• s.16
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• pp.21-32
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• 2009

This study provides an empirical analysis of box office performance for animation movies released in Korea between 2003 and 2008. Two dependent variables are both the number of audiences in the whole country and the number of audiences in Seoul. Such independent variables are employed : power of distributors, the number of screens, release time, sequel/remake, awards, film ratings, nationality, online reviews, and critics' reviews. For the total number of audiences in the whole country, significant variables are the number of screens, the power of USA distributors, Summer release, and online reviews. Since there is no analysis for box office performance for animation movies released in Korean theaters, this study will be considered to be meaningful.

• Solar Energy
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• v.19 no.3
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• pp.43-51
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• 1999

Axisymmetric circular water jet impinges against rectangular heated surface with uniform hear flux and wire-mesh screens are set up in the nozzle-to-heater space to augment heat transfer. In the free jet region to be used them, pressure drop and intensive turbulence flow was brought up. When water jet system is not used wire-mesh screens, maximum heat transfer appears in the stagnation point and the secondary maximum appears X/D=4 but it disappears when they are is used. In the low velocity(Vo<6.0m/s), coarse mesh-screen enhanced heat transfer but fine mesh-screens inpeded heat transfer. In the high velocity(Vo>6m/s), all of them enhanced heat transfer. Average Nusselt number of experimental system to be used wire-mesh screens was promoted $4{\sim}6$times than that of simple water jet system. The stagnation heat transfer of experimental system to be used wire-mesh screens was augmented 6times that of simple water jet system.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.3
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• pp.59-66
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• 1995

In this study through a series of the experiments, 1) the preferable luminance values of the CRT screens, 2) the preferable luminance ratios between the CRT screens and its surrounding surfaces are determined. The results are evaluated by the level of satisfaction, and re-examined by the work performance (number of types, rate of errors) and the level of eye fatique (number of blinks, near point distance)