• Journal of Digital Contents Society
• /
• v.18 no.3
• /
• pp.429-434
• /
• 2017

VR technology has been repidly developing thanks to development of a huge amount of new contents as well as new devices optimized for the virtual environment. Businesses in the IT sector have already started focusing on virtual reality, which might be considered as the center of industry in the future, and concentrated their efforts on development of VR, hardware and technology. Also, development of various VR device would lead to prosperity of media contents based on VR, Still, cyber sickness remain a serious problem waiting for an appropriate solution. In this paper we discuss causes for cyber sickness, analyze the relationship between cyber sickness and reflex eye movement and propose guidelines for the process of producing contents. In addition, we show experiments analyzing the effect of the proposed measures for alleviating cyber sickness.

• English Language & Literature Teaching
• /
• v.8 no.2
• /
• pp.151-176
• /
• 2003

Motivation and learning strategies, some of the important factors affecting language learning, have mostly been studied with reference to their relationship in terms of proficiency. This study investigated motivation and learning strategies and their relationship in order to find the inward predisposition of learners. Data was collected from 200 university students in Taejon and Chungnam province, Korea language learning strategies were measured by the Strategy Inventory for Language Learning(SILL), and motivation by the Attitude / Motivation Test Battery(AMTB), with adaptations for Koreans. The detailed analysis of the data Indicated that Korean university students were more motivated to learn English for a practical goal than a formal one. They had a strong willingness to learn but showed 'the tendency of the new generation' of choosing the easiest and most convenient ways in studying English in terms of motivational intensity and strategy use. Findings imply that there have to be some changes and improvements in the deep-rooted classroom teaching methods. A systematic device is needed to induce students to be autonomous learners, providing them with a variety of activities suitable for their purposes and levels, as in opportunities of contacting native speakers, multi-media language labs, the Internet etc.

• Journal of Oral Medicine and Pain
• /
• v.43 no.3
• /
• pp.61-69
• /
• 2018

Obstructive sleep apnea (OSA) is a relatively common, but greatly underdiagnosed sleep-related breathing disorder, characterized by recurrent collapse of the upper airway during sleep. OSA has been associated with a variety of cardiometabolic disease, such as hypertension, coronary artery disease, cardiac arrhythmia, cerebrovascular disease and metabolic dysfunction. Neurocognitive impairment, including excessive daytime sleepiness, increased risk of motor vehicle accidents, is also related to OSA. Sleep fragmentation and related arousals during sleep lead to intermittent hypoxia, sympathetic activation, oxidative stress, systemic inflammation and metabolic dysregulation which provide biological plausibility to this pathologic mechanism. Extensive studies demonstrated that OSA is a modifiable risk factor for the above mentioned diseases and oral appliances (OAs), although continuous positive air pressure (CPAP) is a first-line therapy of OSA, are not inferior to CPAP at least in mild OSA, and may be an alternative to CPAP in CPAP-intolerant subjects with OSA. The goal of this article is to provide a current knowledge of pathologic link between OSA and cardiovascular disease, focusing on intermittent hypoxia, sympathetic activation, oxidative stress and metabolic dysregulation. Then, previous epidemiologic studies will be reviewed to understand the causal relationship between OSA and cardiovascular disease. Finally, the effects of OAs will be updated via recent metaanalyses compared to CPAP.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.321-325
• /
• 2010

Supersonic ejectors are simple mechanical components, which generally perform mixing and/or recompression of two fluid streams. Ejectors have found many applications in engineering. In aerospace engineering, they are used for altitude testing of a propulsion system by reducing the pressure of a test chamber. It is composed of three major sections: a vacuum test chamber, a propulsive nozzle, and a supersonic exhaust diffuser. This paper aims at the improvement of ejector-diffuser performance by focusing attention on reducing exhaust back flow into the test chamber, since alteration of the backflow or recirculation pattern appears as one of the potential means of significantly improving low supersonic ejector-diffuser performance. The simplest backflow-reduction device was an orifice plate at the duct inlet, which would pass the jet and entrained fluid but impede the movement of fluid upstream along the wall. Results clearly showed that the performance of ejector-diffuser system was improved for certain a range of system pressure ratios, whereas the orifice plate was detrimental to the ejector performance for higher pressure ratios. It is also found that there is no change in the performance of diffuser with orifice at its inlet, in terms of its pressure recovery. Hence an appropriately sized orifice system should produce considerable improvement in the ejector-diffuser performance in the intended range of pressure ratios.

• Journal of the Korea Safety Management & Science
• /
• v.20 no.3
• /
• pp.11-19
• /
• 2018

This study suggests a model of production information system that can reduce manufacturing lead time and uniformize quality by using DNC S/W as a part of constructing production information management system in the industrial field of the existing marine engine block manufacturing companies. Under the effect of development of this system, the NC machine interface device can be installed in the control computer to obtain the quality information of the workpiece in real time so that the time to inspect the process quality and verify the product defect information can be reduced by more than 70%. In addition, the reliability of quality information has been improved and the external credibility has been improved. It took 30 minutes for operator to obtain, analyze and manage the quality information when the existing USB memory is used, but the communication between the NC controller computer and the NC controller in real time was completed to analyze the workpiece within 10 seconds.

• Journal of Korea Game Society
• /
• v.10 no.3
• /
• pp.25-35
• /
• 2010

This paper researched the possibility of applying FMEA that estimates and eliminates the failure modes into the measurement of tangible game's safety. Tangible game with actuation makes unexpected accidents for the game users. And this article tried to give risk priority number to 2 categories, game device and physical injuries using FMEA method. The result showed that TV and Hand laceration and/or bruise were revealed as the most risky factors among the others. In conclusion, it is suggested that FMEA can present integrated, quantitative and coherent measurement for the safety of tangible game.

• Electrical & Electronic Materials
• /
• v.8 no.6
• /
• pp.699-707
• /
• 1995

The material that is both conductive in electricity and transparent to the visible ray is called transparent conducting thin film. It has many fields of application such as Solar Cell, Liquid Crystal display, Vidicon on T.V, transparent electrical heater, selective optical filter, and a optical electric device , etc. In the recent papers on several TCO( transparent conducting oxide ) material, the study is mainly focusing on ITO(indium tin oxide) because ITO shows good results on both optical and electrical properties. Nowaday, in the development of LCD(Liquid Crystal display), the low temperature process to reduce the production cost and to deposit ITO on polymer substrate (or low melting substrate) has been demanded. In this study, we prepared indium tin oxide(ITO) by a cylindrical DC magnetron sputtering with Indium-tin (9:1) alloy target instead of indium-tin oxide target. The resistivity of the film deposited in oxygen partial pressure of 5% and substrate temperature of 140.deg. C. is 1.6*10$\^$-4/.ohm..cm with 85% optical transmission in viaible ray.

• Journal of Information Processing Systems
• /
• v.13 no.4
• /
• pp.731-751
• /
• 2017

The burgeoning distribution of smartphone web applications based on various mobile environments is increasingly focusing on the performance of mobile applications implemented by JavaScript and HTML5 (Hyper Text Markup Language 5). If application software has a simple functional processing structure, then the problem is benign. However, browser loads are becoming more burdensome as the amount of JavaScript processing continues to increase. Processing time and capacity of the JavaScript in current mobile browsers are limited. As a solution, the Web Worker is designed to implement multi-threading. However, it cannot guarantee the computing ability as a native application on mobile devices, and is not sufficient to improve processing speed. The method proposed in this research overcomes the limitation of resources as a mobile client and guarantees performance by native application software by providing high computing service. It shifts the JavaScript process of a mobile device on to a cloud-based computer server. A performance evaluation experiment revealed the proposed algorithm to be up to 6 times faster in computing speed compared to the existing mobile browser's JavaScript process, and 3 to 6 times faster than Web Worker. In addition, memory usage was also less than the existing technology.

• Current Research on Agriculture and Life Sciences
• /
• v.26
• /
• pp.31-43
• /
• 2008

Introduction of construction cost estimating system is necessary to promote appropriate reflection of construction cost and simplified and efficient amount work. The results of this study are as follows. In the results of considering the basic concept and composition of a construction type estimating system, an example orders are concentrated on an apartment house in the country. The building appurtenant work of extension work is high(1.52) as compared with others. In regression analysis for a construction cost, the models are as follows. In a new construction work, (construction cost)=$12,004.8+4.09{\times}$(building area), and in extension work, (construction cost)=$-121.9+4.50{\times}$(building area). Accordingly, this study wishes to compare and analyzes main contents of original cost method and results cost method, and propose predetermined amount estimation device through existent literature study investigation for accumulation of the construction cost.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.9
• /
• pp.1623-1632
• /
• 2008

In food choice, consumers consider importantly food safely and reliability focusing on a high qualify control. Also they are concerned about sustainable production and consumption considering of area and environment. In this paper, We propose and design the high-quality seafood production support system that is based on international sanitary standard haccp, traceability and eco-fiendly seafood certification for safety and reliability of the seafood production. The system is categorized into five part: aquafarm haccp, environmental control monitoring, traceability, disease prevention and messenger service and seafood price inquiry service. The proposed system utilize diverse ubiquitous-it technologies like usn, network cctv, mobile device etc.