• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.2
• /
• pp.85-97
• /
• 2001

A mathematical model was proposed to analyze the damped motion of contact lens which is initially displaced from the equilibrium position. The model incorporates the differential equations and their numerical solution program, based on the formulations of restoring force arising from the capillary action in the tear-film layer between the lens and cornea. The model predicts the capillary action induced surface tension, time dependence of displacement of lens when it is released from the equilibrium position. It seems that the motion of lens is similar to the typical over-damped oscillation caused by the large viscous friction in the liquid layer between the cornea and lens. The effect of variables such as base curves, lens diameters and thickness of tear film layer were illustrated by the computer simulation of the derived program. The time required for the lens to return to the original position increases as the liquid layer thickness increases and it decreases as the diameter of lens increases. With the certain value of base curve the time interval is found to be minimum. The free vibrations of lenses were also simulated varying the parameters such as base curve, diameter, layer thickness. The resonant frequencies are inversely proportional to the liquid layer thickness and it increases as the lens diameter increases. The resonant frequency of lens has a maximum when the diameter is of certain value. If the external impulse or force of the same frequency as the natural frequency of contact lens acted on the cornea in vivo it may cause an excessive movement and thus it might cause the distortion 10 the lens or be pulled off the eye.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.19 no.4
• /
• pp.518-530
• /
• 2013

Purpose: Purpose: The purpose of this study was to provide basic data to develop sexual abuse prevention educational programs for elementary school students. Method: Ninety three third, fourth, fifth, and sixth grade elementary school students were interviewed for content analysis on sexual abuse. Results: The content recognized by elementary school students about sexual abuse was as follows: 1) The concepts of sexual abuse were 'compulsory contact', 'harassment', 'school violence', 'pornography', 'unpleasant sexual behavior' 'crime', and 'don't know'. 2) The causes of sexual abuse were 'intolerance of impulse', 'play', 'bullying', 'financial needs', 'home education and the environment', 'negligence of the victim', and 'don't know'. 3) The methods how to prevent and deal with sexual abuse were 'sexual education', 'avoidance of danger', 'protection', 'self-assertion', 'treat with kindness', 'strengthening of penalties', 'asking for help and notification', 'report', 'treatment and counselling', 'escaping', and 'don't know' 4) Educational needs for prevention of sexual abuse were 'more detailed sexual abuse prevention education', 'how to recognize sexual abuse', 'how to protect oneself', 'interpersonal relationship', 'practical education', and 'none'. Conclusion: These results suggest that based on elementary school students' recognition of sexual abuse, a sexual abuse prevention educational program and content should be organized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.1158-1161
• /
• 2004

This paper presents structural characteristics of station class lightning arresters and electrical characteristics of manufactured ZnO varistor blocks which are usable in those arresters. Three types of station class lightning arresters were investigated and those are a ceramic arrester, a FRP tube type polymer arrester, and a FRP rod type polymer arrester. Each arrester has merits and demerits with structural characteristics. In general, polymer arresters were made of silicon rubber for housing materials, FRP tube or rod for mechanical strength, ZnO blocks for electrical characteristics, and metal parts for electrical contact and the silicon rubber, the housing materials, was directly injected to the arrester module which was assembly composed of electrodes, ZnO blocks and FRP tube or rod, and to prevent the nonlinear electric fields distribution on upper parts of arresters, the grade ring was adopted to the upper electrodes. The reference voltage, nonlinear coefficient, residual voltage, and voltage ratio of manufactured ZnO varistors are 4.90kV, 50, 9.54kV, 1.94, respectively. Compared to designed electrical characteristics, the reference voltage was low for 600v and the voltage ratio was slightly high. However, the characteristics of discharge withstand was so excellent that the mechanical destruction does not occur at the impulse current of $8/20{\mu}s$ 10kA for 100 times.

• Journal of the Korea Convergence Society
• /
• v.12 no.9
• /
• pp.31-37
• /
• 2021

Recently, in the market of home appliances, the technical differentiation of products using convergence technology has been receiving a lot of response to satisfy consumer demand. However, air-conditioner products are an area that requires research and development in the early stages of convergence technology. In this paper, it is developed that a non-contact bio-signal(respiration, movement) collection technology using IR-UWB(Impulse-Radio Ultra Wideband) technology, which controls the air-conditioner direction according to the user's location and also monitors sleep to provide an optimal sleep environment. In addition, emotional lighting and ASMR are developed to provide a comfortable and emotional place of life. Finally, based on the developed convergence technology, we develop intelligent smart air-conditioning services for the convenience of daily life and a comfortable resting space.

• Journal of the Korean earth science society
• /
• v.35 no.1
• /
• pp.29-40
• /
• 2014

A DC resistivity survey was performed to detect anomalies beneath concrete pavement. A set of high conductive media and planar electrodes were used to lessen the effect's a high contact resistance of concrete. Results of the resistivity survey were analyzed and compared with those of other geophysical surveys such as Ground Penetration Radar (GPR), Impulse Response (IR), and Multi-channel Analysis of Surface Waves (MASW), which were carried out in the same location. The results of resistivity survey showed a high resistive distribution in the section of sink and pavement where a pattern of reinforcement was observed through the GPR survey. Also, a comparison of results between the IR and resistivity surveys indicated that the high resistivity was produced by the high dynamic stiffness in the reinforced section. The co-Kriging of both the results of DC resistivity and MASW surveys at the same location showed that an integrated geostatistical analysis is able to give more accurate description on the anomalous subsurface region than can a separate analysis of each geophysical approach. This study suggests that the integrated geostatistical approaches were used for a decision-making process based on the geophysical surveys.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.1
• /
• pp.136-145
• /
• 2007

Redevelopment about land that nature green tract of land and dilapidated city equipment including greenbelt make a strong resolution in city with change of town planning area according to growth of city is consisting. Formation of city of these phenomenon is old and personality of city changes rapidly, the speed becomes fast. Phenomenon that Busan moves to neighborhood area as convenience of traffic of industrial facilities that was on spearhead of economic growth move to outer wall of city and port facilities is deterioration, as becoming decline Tuesday industry form of city in the second industry the third phenomenon that alter by the 4th happen and case of residential area old residential area of inland area change for the worse of habit be and impulse to steal is augmented in the 1970, 80 is appearing. Hereupon the result inland area which analyzes the change with the use area compared to the area where it is coming in contact to the coast the diffusion of the residential area or the business park appears area, the factory back of nine cities acts Gangseo-gu or Gijang-gun of the industry area this with the fact that it changes.