• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.1
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• pp.39-45
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• 2018

Purpose: The purpose of this study was to evaluate the clinical effects of erythritol powder air polishing device (EPAP) in addition to scaling and root planing (SRP) in non-surgical periodontal treatment in moderate chronic periodontitis patients. Materials and Methods: Clinical evaluation was performed at 21 sites treated with SRP (control) and 21 sites treated with the addition of SRP+EPAP (test). All examinations were performed before treatment, 1 month after treatment, and 3 months after treatment. Depth of the periodontal pocket, gingival recession, clinical attachment level, plaque index, and bleeding of probing were measured as clinical parameters. Results: In both test and control groups, there was a significant decrease in the depth of the periodontal pocket, plaque index, bleeding of probing, increased gingival recession, and gain of clinical attachment level at 1 month and 3 months after treatment. However, there was no significant clinical difference between the test group and the control group. Clinical result was improved after 1 month compared to the baseline; in contrast, results at 3 months after treatment were worse than at 1 month after treatment. Conclusion: In this study, we cannot suggest that SRP + EPAP is clinically more effective than SRP alone as non-surgical periodontal treatments. Periodic periodontal therapy, at intervals of at least every three months, is important for sustaining effects of this treatment.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.29-46
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• 2004

It is important to identify geometries of fracture that act as a conduit of fluid flow for characterization of ground water flow in fractured rock. Fracture geometries control hydraulic conductivity and stream lines in a rock mass. However, we have difficulties to acquire whole geometric data of fractures in a field scale because of discontinuous distribution of outcrops and impossibility of continuous collecting of subsurface data. Therefore, it is needed to develop a method to describe whole feature of a target fracture geometry. This study suggests a new approach to develop a method to characterize on the whole feature of a target fracture geometry based on the Fourier transform. After sampling of specimens along a target fracture from borehole cores, effective frequencies among roughness components were selected by the Fourier transform on each specimen. Then, the selected effective frequencies were averaged on each frequency. Because the averaged spectrum includes all the frequency profiles of each specimen, it shows the representative components of the fracture roughness of the target fracture. The inverse Fourier transform is conducted to reconstruct an averaged whole roughness feature after low pass filtering. The reconstructed roughness feature also shows the representative roughness of the target subsurface fracture including the geometrical characteristics of each specimen. It also means that overall roughness feature by scaling up of a fracture. In order to identify the characteristics of permeability coefficients along the target fracture, fracture models were constructed based on the reconstructed roughness feature. The computation of permeability coefficient was performed by the homogenization analysis that can calculate accurate permeability coefficients with full consideration of fracture geometry. The results show a range between $10^{-4}{\;}and{\;}10^{-3}{\;}cm/sec$, indicating reasonable values of permeability coefficient along a large fracture. This approach will be effectively applied to the analysis of permeability characteristics along a large fracture as well as identification of the whole feature of a fracture in a field scale.

• Science of Emotion and Sensibility
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• v.9 no.spc3
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• pp.209-224
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• 2006

Hierarchy which is often named as the tree-structure is used to reduce complexity and show primitive structures of complicated information. This paper aims at explaining information-visualization methods using hierarchies in multimedia domains and prospecting the possible applications by examining how they affect the user's tasks involved in information-seeking activities. As a result, four types of information visualization methods named Treemap, Hyperbolic, Cone Tree and DOI Tree employed in multimedia domain, are presented and pros and cons of each method are explained in this paper. Another important part is defining the core tasks and other related-tasks in information-seeking activities, such as, overview, zoom, filter, details-on-demand, relate, history, and extract. Followings are major findings. Treemap uses 'overview' as the core task, which makes user to gain a overall meaning of the whole information cluster. Hyperbolic and DOI Tree apply 'Boom' task through the function of focus+context or by the function of meaningful scaling to magnify or downsize each node. Cone Tree, also, makes the information organizer to classify the patterns of information acquired in the process of users' information-seeking activities by using 'extract' task. Through this study, it is finally found out that the information-visualization methods using hierarchies in multimedia domains should incorporate the wide variety of functional needs related to users' information-seeking behaviors beyond the visual representation of information.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.85-95
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• 2015

PURPOSES : Recently, bonded concrete overlay has been used as an alternative solution in concrete pavement rehabilitation since its material properties are similar to those of the existing concrete pavements. Deteriorated concrete pavements need rapid rehabilitation in order to prevent traffic jams on Korean expressways. Moreover, speedy and effective repair methods are required. Therefore, the use of bonded concrete overlay with ultra-rapid hardening cement has increased in an effort to reopen promptly the expressways in Korea. However, mobile mixer is required for ultra-rapid hardening cement concrete mixing in the construction site. The use of mobile mixer causes various disadvantages aforementioned such as limitation of the construction supply, open-air storage of mixing materials, increase in construction cost, and etc. In this study, therefore, hydration accelerator in-situ mixing on polymer modified concrete produced in concrete plant is attempted in order to avoid the disadvantages of existing bonded concrete overlay method using ultra-rapid hardening cement. METHODS : Bonded concrete overlay materials using ultra-rapid hardening cement should be meet all the requirements including structural characteristics, compatibility, durability for field application. Therefore, This study aimed to evaluate the application of hydration accelerator in-situ mixing on polymer modified concrete by evaluating structural characteristics, compatibility, durability and economic efficiency for bonded concrete overlay. RESULTS : Test results of structural characteristics showed that the compressive, flexural strength and bond strength were exceed 21MPa, 3.15MPa and 1.4MPa, respectively, which are the target strengths of four hours age for the purpose of prompt traffic reopening. In addition, tests of compatibility, such as drying shrinkage, coefficient of thermal expansion and modulus of elasticity, and durability (chloride ions penetration resistance, freezing-thawing resistance, scaling resistance, abrasion resistance and crack resistance), showed that the hydration accelerator in-situ mixing on polymer modified concrete were satisfied the required criteria. CONCLUSIONS : It was known that the hydration accelerator in-situ mixing on polymer modified concrete overlay method was applicable for bonded concrete overlay and was a good alternative method to substitute the existing bonded concrete overlay method since structural characteristics, compatibility, durability were satisfied the criteria and its economic efficiency was excellent compare to the existing bonded concrete overlay methods.

• Korean Journal of Optics and Photonics
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• v.35 no.5
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• pp.199-209
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• 2024

Predicting the performance of adaptive optics systems is a crucial step in their design and analysis. First-order prediction methods, based primarily on several assumptions and scaling laws, are commonly used. These methods must account for various parameters and error sources, such as the intensity and profile of atmospheric turbulence, fitting errors based on the resolution of the wavefront sensor and deformable mirror, wavefront-sensor noise propagated through the wavefront-reconstruction algorithm, servo lag due to the finite bandwidth of the control loop, and anisoplanatism caused by the arrangement of natural and laser guide stars. However, since first-order performance-prediction methods based on certain assumptions can sometimes yield results that deviate from real-world performance, evaluation through computational simulations and closed-loop tests on a testbed is necessary. Additionally, an atmospheric simulator is required for closed-loop testing, which must adequately simulate the spatial and temporal characteristics of atmospheric disturbances. This paper aims to present an overview of the theory of atmospheric disturbance simulators, as well as their implementation in computational simulation and hardware.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.107-114
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• 2003

This study aims to find methods that prevents aging of buildings paint coating and that limits defects in construction. Defects in painting can occur in four stages: pure paint, during painting, after the paint coating has dried, and after some period of time has passed after coating. Paint may become bad due to precipitation of pigments, formation of membranes, and seeding during manufacturing. Therefore, it is important that the paint is well mixed and kept airtight at a cool, dark place. Indents, paint brush strokes, orange peel, separation of colors, and paint running and spreading during the paint work process can be prevented by using high quality materials and applying a high-level of construction method. After the paint coating has dried, boiling, yellowing, poor drying, poor bonding, and/or glen deficiency may occur. These are influenced by the levels of cleanness of the dried product, drying temperature and hydration. Then, when the coating has been left dried for some period of time, cracking, peeling, scaling, swelling, discoloring, and/or rusting may develop due to the ultraviolet and contaminants in the air. Since these defects occur due to inappropriate construction schedule and/or hot and humid condition, one must use weatherproof materials. Furthermore, poor paint color may be caused by contamination in the sample plate, discoloration, and/or discrepancies in colors which are due to material differences, level of glossiness, degree of dispersion, dual color property of metallic colors, precipitation of pigments, etc. One should achieve reduction in construction cost and effectiveness in paint work by limiting contaminations in the construction site and strictly observing to construction regulations.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.705-715
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• 2010

Objectives : This study is aimed to seek how to promote oral health care by leading the clients with dental fears to change their behaviors in oral hygiene care based on the analysis of the relationships between the dental fears and oral health care behaviors of the clients who visit the Dental Hygiene Education Room. Methods : This study analyzed the 361 dental hygiene records of the subjects with finished treatment and accurate records among a total of 370 clients who had received dental hygiene care at the Dental Hygiene clinic in Y University from March 2007 till June 2009. According to their general features, the study analyzed whether they had any dental fears and why such fears occurred and conducted Chi-square test to compare their oral hygiene care experiences and behaviors with dental fears. Data analysis was made using the SPSS 12.0K for Window, with level of significance set at 0.05. Results : 1. In terms of dental fear or non-fear, the comparison by gender showed that women had a higher level than men, with 76 women(47.2%) answering yes; the comparison by age showed that the age group of 30 years old or older had a higher level than other groups. 2. In terms of dental fear reasons, "the past pain experiences" recorded 34.2%, showing the highest rate. 3. In addition, dental fears had influences on regular dental examination, scaling and dental hygiene education and the subjects without dental fear showed higher levels in terms of tooth-brushing frequency and time. Conclusions : To control "the past pain experiences", future dental treatment should place priority on preventive treatment and get clients to cope with pains through the preliminary education with pains. Besides, to make an effective oral health care of the clients with dental fears, dental hygienists should control the fears of the clients and perform an appropriate oral health care for them using the communication techniques to make friendly and trustworthy impressions.

• Journal of Korean society of Dental Hygiene
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• v.11 no.2
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• pp.149-158
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• 2011

Objectives : The objective of this study was to analyze cognition and status of oral health education of dental hygienists who manage the patients visiting dental clinics and to utilize the findings as continuous study data required for development of systematic oral health education program for management of peridontal disease of adults. Methods : Survey was carried out for 261 dental hygienists working in dental clinics who are performing oral health education of patients with peridontal disease living. Results : 1. In the socio-dynamic diagnosis, it was analyzed that, the younger the age is and the lower the career is, the more the work is centered around assisting medical treatment job and, the older the age is and the higher the career is, the work is centered around oral health education job. 2. In the behavioral diagnosis, it was analyzed that, as to source of knowledge acquisition, guide of dentists and senior dental hygienists was the highest and, as to education media, visual education and demonstration education were mainly used. 3. In educational diagnosis, as to the degree of knowledge about oral health education and the degree of practice, it showed that the degree of knowledge was lower than the degree of practice in peridontal disease process and oral prophylaxis as well as scaling part. 4. In both the cases of independent practice and group practice, it showed that the most frequent obstacle was insufficient educational materials and tools and it was analyzed that acquisition of new knowledge and technology is required as a matter to be improved. Conclusions : It seems to be required for the dental hygienists to develop detailed knowledge and professional technology in order to induce actions and motive of patients during oral health education of peridontal patients and to develop and produce data for efficient education of peridontal patients.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.452-461
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• 2020

The purpose of this study is to identify how learners perceive mobile technology-based learning materials. For this purpose, two methods were utilized. Using multi-dimensional scale(MDS), it was identified that how learners perceive each type of learning materials using mobile technology. Through semantic differential scale(SDS), learners' perception of the difference between mobile learning materials and existing traditional learning materials was analyzed. As a result, learning materials using mobile technology were classified into as follows : the dimension of interaction with the content; the sense of presence. Learners perceived that mobile learning materials had characteristics of 'active', 'learner-centric', 'multi-sensory', and 'stimulating interest'. The significance of this study was to empirically and comprehensively investigate learners' perception for the characteristics of various mobile learning materials.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.4
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• pp.103-112
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• 2017

Purpose : This study was conducted to improve cognitive oral healthcare care by analyzing the correlation between oral health behavior and oral health status Korean adolescents. The subjects were 65,528 youths in 798 schools monitored in the Twelfth Korea Youth Risk Behavior Web-based Survey in 2016. Methods : The general characteristics consisted of 9 items including sex, grade, and academic performance. The academic performance and economic status were restructured into "upper, middle, lower". Subjective health perception and subjective oral health perception were reorganized as "health", "normal", "no health". The sub-areas of oral health behavior include five times of daily brushing during the day yesterday. The number of brushing times was "0", "1-2", "3", "more than 4" After lunch at school, brushing was restructured as "always," "sometimes," "not." The oral health status subscale consisted of 6 items including tooth breakage and toothache at the time of eating. Result : Tooth fracture(43.7 %), pain in mastication(43.7 %), tooth tingling(47.4 %), gum pain and bleeding(45 %), pain in buccal mucosa(43.8 %) and halitosis(46.6 %) were rare in adolescent having healthy oral health status cognitively(P<.001). Nosymptom adolescents without dental sealant showed low tooth fracture(0.64 times), pain in mastication(0.67 times), tooth tingling(0.59 times), gum pain and bleeding(0.84 times), pain in buccal mucosa(0.76 times), and halitosis(0.90 times). Nosymptom adolescents without scaling showed low tooth fracture(0.88 times), pain in mastication(1.03 times), tooth tingling(0.82 times), gum pain and bleeding(0.64 times), pain in buccal mucosa(0.70 times) and halitosis(0.82 times). Conclusion : This study revealed that oral health status is correlated with oral health behavior. Development of educational media and program, and aggressive promotion required to establish oral health Korean adolescent.