• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1259-1263
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• 2004

This paper describes position estimation algorithm using neural network for the navigation of the vision-based wheeled mobile robot (WMR) in a corridor with taking ceiling lamps as landmark. From images of a corridor the lamp's line on the ceiling in corridor has a specific slope to the lateral position of the WMR. The vanishing point produced by the lamp's line also has a specific position to the orientation of WMR. The ceiling lamps have a limited size and shape like a circle in image. Simple image processing algorithms are used to extract lamps from the corridor image. Then the lamp's line and vanishing point's position are defined and calculated at known position of WMR in a corridor. To estimate the lateral position and orientation of WMR from an image, the relationship between the position of WMR and the features of ceiling lamps have to be defined. But it is hard because of nonlinearity. Therefore, data set between position of WMR and features of lamps are configured. Neural network are composed and learned with data set. Back propagation algorithm(BPN) is used for learning. And it is applied in navigation of WMR in a corridor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.44-49
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• 2015

Ceiling cooling and heating system that consider load arrangement and space in the ceiling needs to be developed. Therefore, experimental and economic changes were done to verify the performance of compact type VAV. The test results were as follow. 1) Noise test result, measuring approximately 50.4 dB~56.6 dB (before ceiling in landfill), had a better ceiling deadline than the current measure, about a 10 dB noise reduction, so that the office baseline (40~50 dB) noise was judged to be less than test. 2) For the static pressure test result, taking out an outside hydrostatic 25 mmAq, 24.8 mmAq was measured, respectively, at the point. 3) For the life-cycle cost analysis result, the initial investment cost, maintenance replacement costs, and maintenance costs increased 0.2%, but the energy savings ratio was 19.5% while the whole life cycle savings of 40 years LCC was reduced 11.9%.

• The Journal of Sustainable Design and Educational Environment Research
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• v.4 no.4
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• pp.1-18
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• 2004

Research has been carried out to study thermal environment in a classroom under three kinds of air diffusion temperature and six kinds of air diffusion direction for ceiling type air conditioner. The velocity and temperature distributions of air in the room calculated by 3-dimensional numerical method(PHOENICS), This present study was also conducted to calculate the Air Diffusion Performance Index(ADPI) for cooling conditions and Predicted Percentage of Dissatisfied(PPD) for heating conditions. This analysis shows that the optimum angle of ceiling type air conditioner's diffusion is $15{\sim}30^{\circ}$ for cooling mode and about $15{\sim}45^{\circ}$ for heating mode in these calculating conditions. And also analysis has been carried out to evaluate thermal comfort of vertical and horizontal cross section of classroom.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3141-3147
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• 2010

The most important cause for shortening LED lighting efficiency and life is the junction temperature rises and, to solve this problem, various studies such as thermally efficient packaging, highly conductive material development, contact resistance improvement or heat sink optimization have been studied. However, most studies so far assumed that the LED lights are in the atmosphere, and thermal performance has not been therefore reported when the LED lights are mounted on the ceiling with ceiling unit. Thus, this study investigates the variation of junction temperature of the MR16 LED light under actual installation conditions and more accurate thermal design for the efficiency and life of LED lights is therefore achieved.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.1
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• pp.37-44
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• 2013

The present study examines the effects of periodic type diffusers for producing the preferred acoustics for speech and determines the more successful configurations of sound-absorbing and diffusing treatments for achieving good acoustics in classrooms. The measurements were carried out in a 1/10 scale model classroom systematically adding diffusers to one or more of four surfaces of the room. A total of 13 combination of diffusers with absorptive treatments were investigated. Adding diffusers on the ceiling were more effective to increasing the early-arriving reflection energy($G_{50}$) than adding absorptive materials on the entire ceiling. The late arriving reflection energy($G_{late}$) was decreased with increasing amounts of diffusing treatments of upper front or rear wall and this resulted in achieving higher early-to-late ratios($G_{50}$). Adding diffusers on the upper front wall($AC_{100}DUFW_{26}$) achieved more uniform acoustical conditions over the receiver positions than adding diffusers on the upper rear wall($AC_{100}DUFW_{26}$). Adding diffusers on the ceiling and absorptive materials on the lower front wall($AC_{75}DC_{25}ALFW_{26}$) achieved better acoustical conditions than adding the absorptive materials on the entire ceiling and lower front wall($AC_{100}ALFW_{26}$).

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.1-4
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• 1989

To determine the thickness of coronal hard structure the minimal distance between pupal surface and outer surface of crown was measured by means of Bowley gauge on extracted first molars. Upper(28 teeth) and lower(24 teeth) were carefully collected from 30-39 years of age and male. The teeth were split mesio-distally through central pit. On the split surface various part which are deeply related in cavity preparation were measured (schematic drawing). The results were as follows: A : Distance from mesio-cervical enamel to pulp chamber surface. upper $2.63{\pm}0.19$(mm) Lower $2.18{\pm}0.27$(um) B : Distance from mesial chamber ceiling to mesial surface upper $2.75{\pm}0.34$ Lower $2.62{\pm}0.31$ C : Distance from mesial chamber ceiling to occlusal surface upper $3.82{\pm}0.51$ Lower $3.49{\pm}0.50$ D : Distance from distal chamber ceiling to occlusal surface upper $4.28{\pm}0.69$ Lower $3.90{\pm}0.52$ E : Distance from distal chamber ceiling to distal surface upper $2.79{\pm}0.45$ Lower $2.41{\pm}0.40$ F : Distance from disto cervical enamel to pulp chamber surface upper $2.49{\pm}0.24$ Lower $2.39{\pm}0.25$.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.549-555
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• 2013

Objective: The purpose of this study was to compare the performance of drilling on the ceiling in three different postures (standing, standing on the ladder and supine on the height adjusted board) and the subjective responses of perceived discomfort after the drilling. Background: Overhead work has been identified as a major occupational risk factor and has been a main research subject. Method: Ten young participants drilled 20 holes at the pre-marked places on the ceiling in three different postures. The drilling duration, resting and drilling heart rate were measured. The levels of perceived discomfort at neck, shoulder, elbow, hand and overall body were asked at the end of each task. Results: The working posture affected the heart rate after the drilling. Perceived discomfort in the neck decreased significantly in supine compared to drilling on the ladder. Conclusion: The results of this study suggest that drilling in supine can be an alternative way to reduce the drilling heart rate and the level of perceived discomfort in the neck without sacrificing the productivity. Application: The results of this study would be considered when drilling on the ceiling is required in construction workers.

• The Journal of Sustainable Design and Educational Environment Research
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• v.15 no.1
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• pp.11-18
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• 2016

The purpose of this study is to develop the evaluation model of school facilities in terms of seismic performance during safety education in the school field. This study is composed of four stages with a view to developing user oriented evaluation models that can be utilized during earthquake safety education on ceiling system. and First stage analyze the evaluation guidelines to find evaluation methods and items. Based on the items, site survey was conducted to derive the characteristics of seismic performance of domestic school buildings in terms of ceiling system. Third stage analyzes the seismic performance of ceiling system. Final stage is to derive recommendations based on the results.

• The Korean Journal of Health Service Management
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• v.6 no.4
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• pp.143-152
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• 2012

This study analyzes Korea health panel data (2008) (beta version 1.2) of Korea Institute for Health and Social Affairs, and National Health Insurance Corporation to figure out determinants of healthcare expenditure. In result of Multiple Logistic Analysis, in-patents felt burden on the medical expenditure were 70.0%. As to the patients' payment of medical expenditure, patients over 65 years old had 4.765 times higher than those under 14 years, disabled patients 2.778 than non-disabled patients, chronic patients 1.632 times than non-chronic patients, patients belonging to 12 million won ~ 46 million won and under 12 million won in family income had 1.680 times and 2.168 times respectively than patients with over 46 million won, patients in professional recuperation facility 1.546 times than patients in hospital, patients in private medical institutions 1.700 times than patients in national and public medical institutions, patients using upper grade rooms 1.701 times than patients in non-upper grade rooms. As a health care safety net mechanism to protect people from medical expenditure burden, there is the patients' payment ceiling in the National Health Insurance System. Thus, in order to facilitate the patient's payment ceiling, it is required that the level of ceiling is to be specified according to the income level, and self-payment items is to be included.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.1-7
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• 2004

As we know, topography of korea is composed of many mountains. Also, the volume of traffic is increasing more and more nowadays. So, many tunnels are being constructed to reduce cost of transport and time. Thus, tunnel illumination was considered as the most important thing to make safe traffic conditions. In the past, we installed luminaires on the wall in tunnel, but currently we are installing those on the ceiling. Wherever luminaires are installed on the ceiling, the electric designer may not have known the proper point to install luminaires. Therefore, we researched this project to resolve above problems with abundant experience and accurate data through simulation(Lightscape program). As a result of research, mounting luminaires on the ceiling are better than wall because uniformity is more regular and utilization factor is also higher and then brightness is adequate as well, whereby installation on the ceiling is economical. Therefore, it is suitable that luminaires are installed on the ceiling in tunnel than wall.