• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.65-72
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• 1987

The purpose of this study was to examine the influence of several root canal sealers on the discoloration of internal surface after root canal obstruction. Twenty four sound human premolars, extracted for orthodontic or prosthodontic purposes, were randomly selected and divided into eight groups. Extracted premolars were prepared, and the following seven materials were introduced into the pulp cavities: AH 26, Fuji ionomer (Type I) cement, N2, Oxypara "Murakami", Kerr sealer, PCA sealer, and G-C's Propac ZOE cement. After 7 weeks of incubation; the discolored tooth crowns were hemisectioned, and the internal staining patterns were examined. Then, with an association of observed values the mean intensity scores and percentage of coverage scores of the internal staining patterns in teeth attained by two observers using for Chisquare test were analyzed. The results were as follows: 1. All the experimental premolar's crown showed various ranged discoloration of internal surface. 2. There was no significance between the association scores of two observers participated into this experiments:% coverage scores (P > 0.05) and intensity (P > 0.05) 3. The crowns filled with PCA sealer, AH 26, and Fuji ionomer cement was visible within a depth of one third of dentin. (P> 0.05) 4. For N2, Kerr sealer, and G-C's Propac cement, A slight dentinal staining was recorded, which penetrated up to half way into the dentin. (P> 0.05) 5. It was noticed that the teeth filled with Oxypara "Murakami" were discolored more than two thirds of the dentinal layer. 6. On the control group, there was no discoloration.

• Korean Journal of Metals and Materials
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• v.50 no.2
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• pp.136-145
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• 2012

Resistance spot welding of TRIP780 steels was investigated to enhance understanding of weld fracture mode after tensile shear testing (TST) and L-shape tensile testing (LTT). The main failure mode for spot welds of TRIP780 steels was partial interfacial fracture (PIF). Although PIF does not satisfy the minimum button diameter (4${\surd}$t) for acceptable welds, it shows enough load carrying capacity of resistance spot welds for advanced high strength steels. In the analysis of displacement controlled L-shape tensile test results, cracks initiated at the notch of the faying surface and propagated through the interface of weldments, and finally, cracks change path into the sheet thickness direction. Use of the ductility ratio and CE analysis suggested that the occurrence of PIF is closely related to high hardness and brittle welds, which are caused by fast cooling rates and high chemical compositions of TRIP steels. Analysis of the hold time and weld time in a welding schedule demonstrated that careful control of the cooling rate and the size of a weld nugget and the HAZ zone can reduce the occurrence of PIF, which leads to sound welds with button fractures (BFs).

• Journal of dental hygiene science
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• v.19 no.1
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• pp.31-38
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• 2019

Background: This study aimed to investigate the effects of critical thinking and good communication skills on the problem-solving abilities of dental hygiene students. Methods: A total of 508 dental hygiene students were convenience-sampled from 3 universities. Results: The results revealed that critical thinking had the highest intellectual fairness score of 3.60, and systematicity was the lowest at 3.19. The values for communication skills were high in reaction, social adequacy, and concentration, with an average of 3.65. Problem-solving abilities were in the following order: clarification of the problem, seeking solutions, and decision making. According to general characteristics, more extroverted personalities possessed higher levels of critical thinking, communication skills, and problem-solving abilities (p<0.01). Critical thinking scores were high (p=0.016) in students who responded that peer relationship was difficult; however, their communication skills were the lowest (p<0.001). Additionally, problem-solving abilities were highest among students who reported a difficult peer relationship (p=0.001). The higher the satisfaction with dental hygiene academics, the higher the critical thinking, communication skill, and problem-solving ability (p<0.001). Critical thinking showed a high positive correlation with variables in the following order: clarification of the problem, performing the solutions, seeking solutions, decision making, and evaluation and reflection. The communication skills were also related to these variables listed above (p<0.01). With critical thinking, confidence, watchfulness, intellectual passion/curiosity, sound skepticism, objectivity, and systematicity all influenced the problem-solving ability. Conclusion: Communication skills were influenced by noise control, putting on the other's shoe, social tensions, and efficiency, which affected the problem-solving ability. Dental clinics require dental hygienists to have critical thinking to make analytical judgments and effective communication skills to solve human relation problems with patients and care-givers. Therefore, these skills should be developed in dental hygiene students to improve their problem-solving abilities.

• Journal of Convergence for Information Technology
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• v.9 no.7
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• pp.106-113
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• 2019

The purpose of this paper is aimed to derive suggestions for convergence technology for effective management of distance education by analyzing a long-term case. The experiment was designed with notebook, smartphone or tablet based robot controlled by a remote instructor and a learner, who have experience of distance learning including robot assisted learning. The tablet based robot has the display system of feedback to speakers. During five months, three types of experiments were conducted randomly and a participant was interviewed thoroughly. The result, like the previous research, demonstrates that the task performance of the learner in telepresence robot-assisted learning was better than that in the notebook, and smartphone based. However, it is believed to be necessary to adjust the system for eye-contact and voice transmission for the remote instructor. The instructor required an additional sight by supplementing an extra camera and automatic direction control to source of sound.

• Journal of Sensor Science and Technology
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• v.28 no.5
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• pp.299-304
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• 2019

Recently, the development of rehabilitation medical technology has resulted in an increased interest in speech therapy equipment. In particular, research on articulation therapy for communication disorders is being actively conducted. Existing methods for the diagnosis and treatment of speech disorders have many limitations, such as traditional tactile perception tests and methods based on empirical judgment of speech therapists. Moreover, the position and tension of the tongue are key factors of speech disorders with regards to articulation. This is a very important factor in the distinction of Korean characters such as lax, fortis, and aspirated consonants. In this study, we proposed a Korean electropalatography (EPG) system to easily measure and monitor the position and tension of the tongue in articulation treatment and diagnosis. In the proposed EPG system, a sensor was fabricated using an AgCl electrode and biocompatible silicon. Furthermore, the measured signal was analyzed by implementing the bio-signal processing module and monitoring program. In particular, the bio-signal was measured by inserting it into the palatal from an experimental control group. As a result, it was confirmed that it could be applied to clinical treatment in speech therapy.

• Restorative Dentistry and Endodontics
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• v.43 no.4
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• pp.45.1-45.11
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• 2018

Objectives: This study was conducted to evaluate fluoride release and the micro-shear bond strength of resin-modified glass ionomer cement (RMGIC) in casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-remineralized caries-affected dentin (CAD). Materials and Methods: Exposed dentin surfaces of 30 human third molar teeth were divided into 2 equal groups for evaluating fluoride release and the micro-shear bond strength of RMGIC to CAD. Each group was subdivided into 3 equal subgroups: 1) control (sound dentin); 2) artificially demineralized dentin (CAD); 3) CPP-ACP remineralized dentin (remineralized CAD). To measure fluoride release, 15 disc-shaped specimens of RMGIC (4 mm in diameter and 2 mm in thickness) were bonded on one flat surface of the dentin discs of each group. Fluoride release was tested using ion chromatography at different intervals; 24 hours, 3, 5, 7 days. RMGIC micro-cylinders were built on the flat dentin surface of the 15 discs, which were prepared according to the assigned group. Micro-shear bond strength was measured after 24 hours water storage. Data were analyzed using 1- and 2-way analysis of variance and the post hoc least significant difference test (${\alpha}=0.05$). Results: Fluoride detected in solutions (at all intervals) and the micro-shear bond strength of RMGIC bonded to CPP-ACP-remineralized dentin were significantly higher than those bonded to artificial CAD (p < 0.05). Conclusions: Demineralized CAD consumes more fluoride released from RMGIC into the solution for remineralization than CPP-ACP mineralized dentin does. CPP-ACP increases the micro-shear bond strength of RMGIC to CAD.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.555-567
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• 2019

Speech recognition rate is lowered even in a noisy environment, and it is difficult for a person with a speech disability or an inconvenient language to use it in a social life. In addition to improving the inconvenience of using the language, 280 words were selected using the word selection method which was improved when the word was selected considering the pronunciation characteristics of the language impaired. The MEMS development device used in the experiment was made considering material, lead wire type, length and direction. We improved the speech recognition rate by using the developed word selection method and the MEMS device developed to improve the speech recognition rate due to incorrect pronunciation and severe noise. The new method of selecting words and the mems device were improved and the results were included.

• The Korean Journal of Franchise Management
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• v.11 no.1
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• pp.45-60
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• 2020

Propose: The expansion of the delivery market in franchise business is a positive means of advertising and promotion for franchisees and contributes to substantial sales growth for stores. However, unrestricted and uncontrolled delivery sales and business activity of franchisee directly lead to encroachment of business territory between franchisees, resulting in increased operating costs of franchisees and conflicts between franchisees over rights and interests on franchise business. Moreover, in relation to the restrictions on the opening of competitors, it is incapacitating the law intent of prohibiting unfair encroachment of business territory, in the issue of the Fair Franchise Act in regard to guarantee of exclusive sales and business activity rights of franchisee. This study aims to point out major problems arising out of franchisee's infinite competition on delivery sales and business activity that are not restricted or controlled and then suggest legal supplements, policy tasks, and practical implications for improvement on the issues. Literature Review: In franchising business transactions, vertical restraints are associated with the exclusive territory establishment, control of transaction area, restriction of intangible sales and business activity of franchisee. Therefore, in the franchise business, it is necessary to take positive interpretation and application on e-commerce, the area of e-commerce, and delivery trading area and find proper and practical ways, by virtue of constructive attitude of each actor, to reduce the encroachment of business territory and various conflicts caused by unrestricted delivery trading area. Conclusion and suggestion: The finding shows that unrestricted or uncontrolled delivery sales and business activity of franchisees cause encroachment of business territory and many conflicts among franchisees. And this matters also weaken the legislation of the law on the protection of the business territory and can be negative factors that disrupt the protection of identity and sound development of the franchise industry in the long run. Therefore, in the franchise business, it is necessary to take positive interpretation and application on e-commerce, the area of e-commerce, and delivery trading area and find proper and practical ways, by virtue of constructive attitude of each actor, to reduce the encroachment of business territory and various conflicts caused by unrestricted delivery trading area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1397-1406
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• 2019

In everyday mobile phone calls between the disabled and non-disabled people due to neurological impairment, the communication accuracy is often hindered by combining the accuracy of pronunciation due to the neurological impairment and the pronunciation features of the disabled. In order to improve this problem, the limiting method is MEMS (micro electro mechanical systems), which includes an induction line that artificially corrects difficult vocalization according to the oral characteristics of the language impaired by improving the word of out of vocabulary. mechanical System) Microphone device improvement. S/W improvement is decision tree with invert function, and improved matrix-vector rnn method is proposed considering continuous word characteristics. Considering the characteristics of H/W and S/W, a similar dictionary was created, contributing to the improvement of speech intelligibility for smooth communication.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1325-1330
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• 2020

New-born babies who require special attention medically are admitted often to incubator. Incubators are well equipped to fulfill take care of infants, but they have to hospital and so expensive. This paper proposes a smart incubator that can solve the problem of convenience and cost aspect of these incubators. Developed incubator enables near-field monitoring using Arduino Uno as the main control device and Bluetooth communication. The environment in the incubator measures temperature and humidity using a DHT22 sensor and the sound using a P5510 microphone. If the temperature and humidity data set by the user are lower or higher than the reference value, it is designed to operate the heating pad using the controller or turn on the fan to allow air circulation. The measured values in the incubator are displayed in real time on the user's smartphone monitoring screen and are programmed using app inventor. Developed incubators can help take care of infants at low cost in the home.