• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.1337-1338
• /
• 2013

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3150-3155
• /
• 2007

This paper describes an experimental work to investigate the effect of mesh screen device on the jet structure and acoustic characteristics of over-expanded supersonic jet. The mesh screen device is placed into the supersonic jet stream. In order to perturb mainly the initial jet shear layer, the hole is perforated in the central part of the mesh screen. The diameter of the perforated hole and the location of mesh screen device are varied. A Schlieren optical system is used to visualize the flow fields of supersonic jet without and with the mesh screen device. Pitot pressure measurement is carried out to obtain the pressure distribution in the jet flow. Acoustic measurement also is performed to obtain the OASPL and noise spectra. The results obtained show that the jet structure and the jet noise control effectiveness is strongly dependent upon the diameter of the perforated hole and the location of the mesh screen device in the jet stream. Provided that the mesh screen device is placed at the location to perturb effectively the initial shear layer, the present control method is effective in suppressing the supersonic jet noise.

• Journal of the Ergonomics Society of Korea
• /
• v.18 no.2
• /
• pp.81-89
• /
• 1999

User's characteristics on the screen adjustment of color TV were studied. Two experiments were performed. In the first experiment, the characteristic of screen adjustment according to TV program, ambient luminance, and gender was investigated. Twenty subjects (10 females and 10 males) were participated in this experiment. Set points of brightness, contrast, tint, and color were measured on TV screen and analyzed. Brightness and contrast were significant on gender at significant level 0.01 and color was significant on gender at significant level 0.1. Tint was significant on program at significant level 0.01. The second experiment was performed to supplement the first experiment. The influences of ambient luminance, presented image, screen setting criteria, and gender were investigated. We simplified the first experiment in the second one. We restricted dependent variables (screen control variables) to only two, brightness and contrast. Other control variables were fixed to middle values. Brightness and contrast were significant on gender and screen setting criteria at significant level 0.01. In conclusion, we found that ambient luminance and presented image had no significant effects on TV screen adjustment and TV program had only a significant effect on tint. However, we found that gender and screen setting criteria had significant effects in most conditions.

• Journal of Korea Multimedia Society
• /
• v.19 no.3
• /
• pp.567-572
• /
• 2016

N-screen is an emerging technology to support multimedia multicasting, content sharing and content mobility. N-screen service providers should obtain the technology that provides the highest quality content seamlessly. Distributed nature of WiMedia distributed-MAC protocol can provide full mobility support, and achieves seamless medium access method in contrast to IEEE 802.15.3. So, in this paper, WiMedia distributed-MAC protocol is adopted and an asynchronous multicast transmission (AMT) technology is proposed to enhance performance of seamless N-screen wireless service based on distributed-MAC. The ACK frame transmissions are not required for multicast transmissions. By using this property in AMT, if a device is a multicast receiver, its reserved time slots can be reserved by the other devices with 1-hop distance. Furthermore, each N-screen device broadcasts and shares the information including an order in asynchronous traffic reservations to reduce conflicts in determining the transmission order of asynchronous N-screen packets. Therefore, AMT scheme expands the number of time slots available and throughputs for multicast and asynchronous traffic reservations when comparing with the distributed-MAC standard system. N-screen communications based on distributed-MAC with the proposed AMT shows a new framework for realizing N-screen wireless service with the full content mobility.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.3
• /
• pp.590-598
• /
• 1988

Viscous flows through a screen normal to an uniform flow are numerically simulated. A .kappa.-.epsilon. model is adopted for evaluation of the Reynolds stresses. The existence of a screen is regarded as extra sources in the momentum equations. The amount of extra sources is related to the resistance coefficient and the refraction coefficient of the screen. Flows are numerically simulated for various resistance coefficients and heights of the screen and Reynolds numbers. The present method has been verified to reasonably simulate viscous wakes and shear layers of the screen, for which the inviscid theory is quite limitted. As the fluids approach the screen, the velocity is reduced and the pressure is raised to satisfy the Bernoulli equation. After passing the screen, the velocity shows its minimum value at the down-stream, but static pressure is slowly recovered. A detached separation-bubble from the screen appears as the resistance coefficient is increased to a certain level. Such results are qualitatively in agreement with limitted experimental data available. The turbulent kinetic energy shows its maximum value at further down stream and decrease thereafter.

• Journal of Korea Game Society
• /
• v.16 no.3
• /
• pp.117-126
• /
• 2016

Screen climbing is a kind of screen sports. In screen climbing, the software program is executed in a computer system and climbing is progressed by the interaction between a climber and the content of the screen. We implemented a screen climbing game with the ancient cave exploration considering the development of children and the children's motivation to sports climbing. The content of the game is projected to the artificial climb wall and the interaction between a user and the game is done by a user's input of Kinect's depth data. The game is popular with the children in the children's exhibition event. There should be implemented more screen climbing game.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.1
• /
• pp.139-146
• /
• 2014

Through numerous mobile device technology advances, various multimedia contents is moving towards mobile devices from existing personal computer (PC). These paradigm has emerged taking into account these idea, the so-called N-Screen, N-Screen is user-centric service to provide running and sharing on everywhere via advanced smart system in C-P-N-T (Content, Platform, Network, Terminal). Therefore we must provide securing of various contents, openended platform, and user-centric service for efficient N-Screen service. For These characteristic of N-Screen, this paper propose design and implementation of user location-based N-Screen service system. The proposed system realize user location through user's smart phone and offer automatic streaming service to user. And also, we provide web service-based extended N-Screen service. Thus, user can access various device, such as laptop, tablet, and mobile device.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.12
• /
• pp.217-223
• /
• 2009

This study is to analyse the impacts of screen quota in the screen industry and suggests policy implications. To achieve the purpose of this study, we reviewed the theoretical base and history of screen quota, and analyze the share ratio of domestic films and the impacts of screen quota on the actors concerned it. The screen quota was introduced for the purpose of cultural diversity and the protection of screen industry. But it constrained consumer's choice and owner's property. This study suggested policy implications bases the analytical results.

• Fire Science and Engineering
• /
• v.32 no.2
• /
• pp.82-91
• /
• 2018

This study analyzed the working conditions and problems of screen fire shutters in the Goyang Bus Terminal fire based on the fire investigation results. At that time, screen fire shutters in the 1st basement, which was under construction, did not work because the power was shut off. Four screen fire shutters in the 1st and 3rd floor did not work despite the power not being shut off. The following problems related to a screen fire shutter were found: shutting off the power to screen fire shutters for the fire compartment on each floor, even when the fire compartments were changed in each area; installing an integral type screen fire shutter without any regulations, installing a two-stage screen fire shutter in a place not related to obstacles during evacuation; stopping the function of the screen fire shutters for a fire compartment on each floor after a combustible sandwich panel was comparted; installing a screen fire shutter over 10 meters in width, in which its performance was not verified; and no safety control standards for reinstalling or maintaining a screen fire shutter.

• The Journal of the Korea Contents Association
• /
• v.20 no.10
• /
• pp.268-283
• /
• 2020

The purpose of this study was to examine the effect of exposure to body image in media and bullet screen on weight loss intention by specifically focusing on Bilibili, a video sharing website of China. For the study, a 3 (Social viewing: no bullet screen vs. complimentary bullet screen vs. critical bullet screen) x 2 (Body image in media: ideal vs. realistic) between-subjects factorial design was conducted. A total of 310 Chinese women in their 20s were recruited to participate in an experimental survey. The main results showed that viewing the ideal body image with the complimentary bullet screen and realistic body image with the critical bullet screen strengthened the participants' intention on weight loss. Finally, the interaction effect of social viewing and the types of bullet screen were examined. The higher weight-loss intention was revealed when social viewing was conducted with the complimentary bullet screen of the ideal image. The results of this study can enhance the understanding of the bullet screen as a type of social viewing and its effect on user behavior intention.