• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.255-264
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• 2012

Purpose: In this study, the effect of lens fitting status on the contact area between spherical/aspherical RGP lens and the cornea having different astigmatic degree and corneal type was investigated for guiding the proper selection of RGP lens. Methods: Spherical and aspherical RGP lenses were applied on ninety eyes $(25.12{\pm}3.52years)$ having with-the-rule astigmatism by different fitting status. Then, their central, mid-peripheral and peripheral areas of fluorescein pattern were calculated and compared for the quantitative evaluation of the contact area between spherical/aspherical RGP lens. Results: The central and peripheral areas with the alignment fitting was significant different based on lens design. However, the central area didn't show any significant difference by lens design and corneal type when fitted in steep or flat. When analyzed by the corneal shape, both lenses with alignment and flat fitting had significant difference in central and peripheral areas. However, the central, mid-peripheral and peripheral areas with steep fitting didn't show the difference by corneal types. When analyzed by the astigmatic degree, the central and peripheral areas with alignment fitting changed proportionally to the increase of corneal astigmatism regardless of corneal shape. With steep and flat fitting, however, the central, mid-peripheral and/or peripheral areas in round- and symmetric bowtie-typed corneas showed the conflicting result when compared to those of alignment fitting when analyzed by the astigmatic degree. Conclusions: In this study, it was confirmed that the contact areas of cornea and RGP lens fitted steep and flat status were largely affected by the corneal type and corneal astigmatism rather than RGP lens fitted in alignment status. Also, this result commonly occurred in both spherical and aspherical RGP lenses.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.328-334
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• 2020

Clinical remounting of complete denture is performed to refine occlusal harmony in maxillo-mandibular relation. It has been reported that patients who used adjusted dentures with clinical remounting felt less complications such as pain and discomfort in mastication. The purpose of this study was to assess effects of clinical remounting with case series. Seven patients with existing complete prosthesis were included. Clinical remounting procedure was done through interocclusal relation recording. In addition, occlusal force was measured with pressure indicating sensor and occlusal contact areas were evaluated with photo occlusion analysis. Occlusal contact areas of prosthesis were enlarged, while bite pressure was not increased. Hit and slide phenomenon of prosthesis was reduced concurrently. Clinical remounting procedure improved denture stability and increased occlusal contact area. Therefore, clinical remounting should be considered.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.39-46
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• 2018

Two surfaces that have relative motion show different characteristics according to surface roughness or surface patterns in all lubrication areas. For two rough surfaces with mixed lubrication, this paper proposes a new approach that includes the contact characteristics of the surfaces and a probabilistic method for a numerical analysis of lubrication. As the contact area of the two surfaces changes according to the loading conditions, asperity contact is very important. An average flow model developed by Patir-Cheng is central to the study of lubrication for rough surfaces. This average flow model also refers to a multi-asperity contact model for deriving a modified Reynolds equation and calculating the lubricant characteristics of a bearing surface with random roughness during fluid flow. Based on the average flow model, this paper carried out a numerical analysis of lubrication using a contact model by considering a load change made by the actual contact of asperities between two surfaces. Lubrication properties show different characteristics according to the surface patterns. This study modeled various geometric surface patterns and calculated the characteristics of lubrication.

• Journal of Information Display
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• v.8 no.1
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• pp.1-5
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• 2007

We have developed a CMOS LTPS process which requires only five photolithographic masks and only one ion doping step. Drain/Source areas of NMOS TFTs were formed by PECVD deposition of a highly doped precursor layer while PMOS contact areas were defined by ion implantation. Single TFTs, inverters, ring oscillators and shift registers were fabricated. N and p-channel devices reached field effect mobilities of $173cm^2$/Vs and $47cm^2$/Vs, respectively.

• Journal of East-West Nursing Research
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• v.13 no.2
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• pp.107-117
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• 2007

Purpose: This study was to examine the possibility of the contact with pornographs of elementary school boys and girls and to confirm responses after that, and to compare the feeling of sexual conflict between the boys and girls. Methods: The subjects were 952 5th and 6th graders of elementary school in four city areas(456 boys, 496 girls). Data collection was via questionnaires Results: Except several pupils(34.4% of boys, 27.4% of girls), most of subjects of the study had no contact with pornographs. The response after the contact with pornographs was feeling of shame the most, which was a negative reaction. The sexual conflict appeared more in pupils who had contact with pornographs than in those who had not boys(t=3.84, p<.000), girls(t=3.96, p<.000), which showed a significant difference. However, the conflict between boys and girls was not significant statistically. Conclusion: We would like to suggest that a sound control system must be prepared and a development of programs related to sexual education and promotion of ability fighting against them that can release their impulse of sex.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1326-1330
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• 2008

The failure mode of steel road wheels in a vehicle is cracks from ventilation hole through to contact plane on steel wheel's disc plate. But a number of cracks of Cornering Fatigue Limit Test is on contact plane near to wheel nut mounting area, even though it's satisfied with specified cycles. So this paper searches out causes to improve durability and reliability of C.F.T by uni-axial bending moment test. The verified cause is a "fretting" on contact area of steel wheel. In result, this paper suggests a solution to prevent a fretting by inserting a damping shim, 0.7mm between steel wheel contact areas. Therefore this paper makes it possible to move crack position of C.F.T in steel wheel from contact plane to vehicle's failure mode.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.16-21
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• 2008

The demand for three-dimensional (3D) shape measurements is increasing in a variety of fields, including the manufacture of molds and dies. The most popular technology for 3D shape measurement is the coordinate measuring machine (CMM) with a contact trigger probe. Although a CMM provides a high degree of accuracy, it is inefficient due to its long measuring time. It also has difficulty measuring soft objects that can be deformed by the touch of the contact probe. In addition, a CMM cannot digitize areas that are difficult to reach, and cannot capture very minute details on the surface of complex parts. For these reasons, optical non-contact measurement techniques are receiving more attention since they eliminate most of the problems associated with contact methods. Laser scanning is emerging as one of the more promising non-contact measurement techniques. This paper describes various acquisition considerations for laser scanning, including the accuracy of the 3D scan data, which depends on the charge-coupled device (CCD) gain and noise. The CCD gain and noise of a 3D laser scanner are varied while keeping the other conditions constant, and the measurement results are compared to the dimensions of a standard model. The experimental results show that a considerable time savings and an optimum degree of accuracy are possible by selecting the proper CCD gain and noise.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.644-662
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• 2023

There are still outbreaks of COVID-19 across the world. Ships increase the risk of worldwide transmission of the virus. Close contact tracing remains as an effective method of reducing the risk of virus transmission. Therefore, close contact tracing in ship environments becomes a research topic. Exposure Notifications API (Application Programming Interface) can be used to determine the encountered location points of close contacts on ships. Location points of close contact are estimated by the encountered location points. Risky areas in ships can be calculated based on the encountered location points. The tracking of close contacts is possible with Bluetooth technology without the Internet. The Bluetooth signal can be used to judge the proximity among detecting devices by using the feature that Bluetooth has a strong signal at close range. This Bluetooth feature makes it possible to trace close contacts in ship environments. In this paper, we propose a method for close contact tracing and showing the risky area in a ship environment by combining beacon and Exposure Notification API using Bluetooth technology. This method does not require an Internet connection for tracing close contacts and can protect the personal information of close contacts.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.302-322
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• 1998

This study was accompolished to analyze and compare the number and area of the occlusal contact points in healthy volunteers and athletes with normal occlusion. For this study, 15 athletes(13 amles and 2 females with average age 20) and 21 healthy volunteers(14 mles and 7 females with average age 20.09) were selected. The visual display acquired by scanning of occlusal record in maximal intercuspation was converted into 16 gray value image. Then, using computer program(J & Lee Occlusal Analyser), the pixel which was in definite range of the gray value was recognized, and the numbers of recognized pixel were calculated to area. The results were as follows ; 1. The average numbers of total occlusal contact feints were 31.05 in control group, and 34.67 in athlete group. The average area of total occlusal contacts was $100.25mm^2$ in control group, and $127.78mm^2$ in athlete group. 2. In control group, the average numbers of occlusal contact points were revealed in order as follows ; the first molar(8.48), the second molar(8.24), the second premolar(4.71), the lateral incisor(2.90), the first premor(2.43), the central incisor(2.19), and the canine(2.1). The least average in canine(2.1) was similar to the average(2.19) in central incisor and (2.09) in lateral incisor. In athlete group, the average numbers of occlusal contact points were revealed in order as follows ; the first molar(8.97), the second molar(8.47), the second premolar(5.60), the canine(3.80), the lateral incisor(3.33), the first premolar(2.67), and the central incisor(1.93). 3. In control group, the average areas of occlusal contact surface were revealed in order as follows ; the first molar($39.47mm^3$), the second molar($37.54mm^3$), the second premolar($9.54mm^3$) the first premolar($6.18mm^3$), canine($3.49mm^3$), the central incisor($2.76mm^3$), and the lateral incisor($1.28mm^3$). In athlete group, the average areas of occlusal contact surface were revealed in order as follows ; the first molar($44.11mm^3$), the second molar($40.69mm^3$), the second premolar($16.50mm^3$), the first premolar($9.39mm^3$), the canine($5.08mm^3$), the lateral incisor($3.7mm^3$), and the central incisor($2.25mm^3$). 4. With aging in both control and athlete group, there was a decreasing tendancy in average number of occlusal contact point, and was an increasing tendancy in average area of occlusal contact surface. In comparison at each age, both the numbers and area of occlusal contact were greater in athlete group than in control group. It was not significant in the numbers of occlusal contact points beween athlete and control group(p>0.1), but significant in the area of occlusal contact surface(p<0.03). 5. In comparision as to the kind of sports(Gymnastics : 2, Rugby : 3, Soccor : 5, Ice hocky : 5), the numbers of occlusal contact points were the most in ice hocky, and the area of occlusal contact surface was the greatest in gymnastics. With increasing a career in athlete group, there was a decreasing tendancy in average numbers of occlusal contact points and was an increasing tendancy in average area of occlusal contact surface. 6. By T-scan analyzing, the contact numbers on the anterior teeth were greater in control group than in athlete group, and on the posterior teeth were greater in athlete group than in control group. And the results acquired by T-scan were lesser than that caquired by the silicone bite records. It was not significant in the posterior teeth, but significant in the anterior teeth. In T-scan records, the numbers of occlusal contact points on second molar were the greatest, but in the silicone records, the numbers on first molar were the greatest.

• Korea Journal of Hospital Management
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• v.27 no.2
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• pp.16-33
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• 2022

Purposes: Prompt evaluation of routes and contact tracing are very important for epidemiological investigations of coronavirus disease 2019 (COVID-19). To ensure better adoption of contact tracing apps, it is necessary to understand users' expectations, preferences, and concerns. This study aimed to identify main reasons why people use the apps, appropriate services, and basis for voluntary app services that can improve app participation rates and data sharing. Methodology/Approach: This study conducted an online survey from November 11 to December 6, 2020, and received a total of 1,048 survey responses. This study analyzed the questionnaire survey findings of 883 respondents in areas with many confirmed cases of COVID-19. This study used a multiple regression analysis. Findings: Respondents who had experience of using related apps showed a high intention to use contact-tracing apps. Participants wished for the contact tracking apps to be provided by the government or public health centers (74%) and preferred free apps (93.88%). The factors affecting the participants' intention to use these apps were their preventive value, performance expectancy, perceived risk, facilitative ability, and effort expectancy. The results highlighted the need to ensure voluntary participation to address participants' concerns regarding privacy protection and personal information exposure. Practical Implications: The results can be used to accurately identify user needs and appropriate services and thereby improve the development of contact tracking apps. The findings provide the basis for voluntary app that can enhance app participation rates and data sharing. The results will also serve as the basis for developing trusted apps that can facilitate epidemiological investigations.