• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.515-519
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• 2004

Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOV A and the Scheffe test at the 95% confidence level. The results of this study were as follows: 1. The mean fracture strength decrease in following sequence Group 1 (4558.90{\;}\pm{\;}77.40{\;}N$), Group 2 ($494.07{\;}\pm{\;}123.98{\;}N) and Group 3 ($267.33{\;}\pm{\;}27.02{\;}N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.

• Earthquakes and Structures
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• v.17 no.5
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• pp.511-519
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• 2019

The concrete gravity dam is one of the most important parts of the nation's infrastructure. Besides the benefits, the dam also has some potentially catastrophic disasters related to the life of citizens directly. During the lifetime of service, some degradations in a dam may occur as consequences of operating conditions, environmental aspects and deterioration in materials from natural causes, especially from dynamic loads. Cumulative Absolute Velocity (CAV) plays a key role to assess the operational condition of a structure under seismic hazard. In previous researches, CAV is normally used in Nuclear Power Plant (NPP) fields, but there are no particular criteria or studies that have been made on dam structure. This paper presents a method to calculate the limitation of CAV for the Bohyeonsan Dam in Korea, where the critical Peak Ground Acceleration (PGA) is estimated from twelve sets of selected earthquakes based on High Confidence of Low Probability of Failure (HCLPF). HCLPF point denotes 5% damage probability with 95% confidence level in the fragility curve, and the corresponding PGA expresses the crucial acceleration of this dam. For determining the status of the dam, a 2D finite element model is simulated by ABAQUS. At first, the dam's parameters are optimized by the Minitab tool using the method of Central Composite Design (CCD) for increasing model reliability. Then the Response Surface Methodology (RSM) is used for updating the model and the optimization is implemented from the selected model parameters. Finally, the recorded response of the concrete gravity dam is compared against the results obtained from solving the numerical model for identifying the physical condition of the structure.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.27 no.4
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• pp.45-57
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• 2014

Objective : This study aims to provide fundamental data for new directions(the improvement directions) from searching research papers of randomized controlled trials among thesis of Atopic Dermatitis related to oriental medicine in Korea from 2004 to 2014 and identifying the problem and level of a clinical study through an assessment of the quality, CONSORT statement. Methods : Data was collected through the Koreanstudies Information Service System(KISS). Two experts in Oriental Medicine reviewed the title and abstract in thesis, the results of searching the title, "Atopic dermatitis" and topic, "oriental medicine" at KISS, and then they handsearched Randomized Controlled Trials related to oriental medicine in Korea. According to guidelines defined by CONSORT statement, they assessed whether 37 items were followed by guidelines at yes or no answers in order to evaluate the quality as well. They assessed the definition of each item independently. After comparing, they made a decision on the item of different outcomes through an agreement with a third party. Results : Total number of randomized controlled trials in Atopic Dermatitis related to oriental medicine is eleven. A randomized controlled trial was first published in 2007. One or two papers associated it were released every year except 2013. 9 papers of them were approved by Institutional Review Board and were received written consent. The study included between 20 to 40 subjects for 2-arm parallel study design. The effect of treatment was observed for 4 to 8 weeks. On average, the number followed guidelines was 18.64 among those of 37 CONSORT statement and 50.38% of them was followed overall. Conclusion : As an interest about randomized controlled trials was increased, it was needed to care the standard providing information of CONSORT statement on randomized controlled trials related to oriental medicine in Korea. It is suggested to provide more clear information about it, so that it can be a motive for improving quality of the journal in oriental medicine.

• PNF and Movement
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• v.13 no.1
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• pp.9-16
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• 2015

Purpose: This study aimed to examined the effects of upper and lower limb coordinated exercise of proprioceptive neuromuscular facilitation (PNF) on static and dynamic balance ability. Methods: The subjects of this study were 18 patients who had been diagnosed with a stroke and hospitalized and who had received rehabilitation treatment at D rehabilitation hospital located in J city. They were randomly and equally assigned to a PNF upper and lower limb coordinated exercise group and an ordinary central nervous system development and treatment group, and they conducted exercises for eight weeks. They carried out exercise three times per week, for 30 minutes per each time. After each four minutes of exercise, each participant was given a and rest for one minute after exercise for four minutes was given. In order to test the subjects' static and dynamic balance ability and their dynamic balance ability, frailty and injuries,: a cooperative studyies of intervention techniques (FICSIT-4) test, a four- step square test (FSST), a timed up and go test (TUG), and a TWT3M tests wasere conducted before and after the exercise. Descriptive statistics were taken for the general characteristics of the subjects, and an independent t-test was conducted both before and after the exercise in order to examine differences between the two groups before and after the exercise were conducted. The A statistical significance level was set at p= 0.05. Results: In all the tests (of FICSIT-4, FSST, TUG, and TWT3M), both the experimental group and the control group saw more improved results, but the experimental group's results were significantly higher than those of the control group, and the size of the effects was larger in the experimental group than in the control group, with statistically significant results. Conclusion: PNF upper and lower limb coordinated exercise applied to chronic stroke patients produced brought significant results in static and dynamic balance ability. PNF and is considered as an important intervention program to improve stroke patients' balance ability.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.27-35
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• 2021

Artificial life is used in various fields of applied science by evaluating natural life-related systems, their processes, and evolution. Research has been actively conducted to evolve physical body design and behavioral control strategies for the dynamic activities of these artificial life forms. However, since co-evolution of shapes and neural networks is difficult, artificial life with optimized movements has only one movement in one form and most do not consider the environmental conditions around it. In this paper, artificial life that co-evolve bodies and neural networks using predator-prey models have environmental adaptive movements. The predator-prey hierarchy is then extended to the top-level predator, medium predator, prey three stages to determine the stability of the simulation according to initial population density and correlate between body evolution and population dynamics.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.6
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• pp.240-246
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• 2021

In the ceramic industry, a drastic decrease in crystalline formation was found even among the glazes well known for their high crystalline productivity when the ceramic glaze was stored in wet conditions over a period. This study aimed to investigate the reason for decreasing willemite crystals during storage. As the starting materials ZnO, calcined ZnO and frit 3110 are selected; the composition for zinc crystalline glazes was set through a three-component system with the materials. The firing condition was used from previous studies. The study was observed how wet conditions affected the crystallization of zinc crystalline glazes from a day to 24 weeks. The results were obtained by particle size analysis, XRD, Raman spectroscopy and SEM analysis. The results indicated that ZnO is advantageous in terms of willemite crystalline development and growth; however, Zn(OH)₂ cluster, formed by the reaction with water during the storage, caused the decrease in ZnO level in the glaze. The reduction of ZnO in the glaze eventually interfered the willemite development and growth.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.58-67
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• 2019

The low-voltage connection box used as a low-voltage transmission line of KEPCO is intended to branch or connect to an underground line. In comparison with the utility considering the aesthetics of the distance, and safety measures are needed. In this paper, temperature and humidity, $CO_2$, water level, acceleration, and vibration sensor are installed inside the underground low voltage handhole, and the sensor data is transmitted to the ground using the Zigbee module. Antenna (Bolted Antenna) for communication with the ground was proposed and the data reception through it was confirmed. In the LF mode and the HEX mode, the transmitted data was confirmed to be a perfect reception success rate. In the case of the bolted antenna, the difference between the ground state and the underwater state was observed as a result of the experiment in the environmental environment. However, It was judged that reception sensitivity was sufficient for communication. The received data could be confirmed through PC based GUI.

• Smart Structures and Systems
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• v.23 no.3
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• pp.307-318
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• 2019

The frequently excessive vibrations presented in civil structures during seismic events or service conditions may result in users' discomfort, or worst, in structures failure, producing economic and even human casualties. This work contributes in proposing the synthesis of a nonlinear optimal control strategy for semiactive structural control, with the main characteristic that the synthesis considers both the structure model and the semiactive actuator nonlinear dynamics, which produces a nonlinear system that requires a nonlinear controller design. The aim is to reduce the unwanted vibrations in the response of civil structures, by means of intelligent fluid semiactive actuator such as the Magnetorheological Damper (MRD), which is a device with a low level of power consumption. The civil structures for which the proposed control methodology can be applied are those admitting a state-dependent coefficient factorized representation model, such as buildings, bridges, among others. A scaled model of a three storey building is analyzed as a case study, whose dynamical response involves displacement, velocity and acceleration of each one of the storeys, subjected to the North-South component of the September 19th., 2017, Puebla-Morelos (7.1M), Mexico earthquake. The investigation rests on comparing the structural response over time for two different conditions: with no control device installed and with one MRD installed between the first floor and the ground, where a nonlinear optimal signal for the MRD input voltage is determined. Simulation results are presented to show the effectiveness of the proposed controller for reducing the building's dynamical response.

• Journal of Platform Technology
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• v.6 no.4
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• pp.69-77
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• 2018

In the case of personal information files containing personal information, there is insufficient awareness of personal information protection in end-point areas such as personal computers, smart terminals, and personal storage devices. In this study, we use Diffie-Hellman method to securely retrieve personal information files generated by web crawler. We designed SEED and ARIA using hybrid slicing to protect against attack on personal information file. The encryption performance of the personal information file collected by the Web crawling method is compared with the encryption decryption rate according to the key generation and the encryption decryption sharing according to the user key level. The simulation was performed on the personal information file delivered to the external agency transmission process. As a result, we compared the performance of existing methods and found that the detection rate is improved by 4.64 times and the information protection rate is improved by 18.3%.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.146-159
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• 2018

This study analyzed what premium features significantly affect customer satisfaction and their recommendation, and what factors significantly affect product attributes. In the process, first, the loyalty program and the customer compensation program were studied to determine the impact of the customer satisfaction and recommendation. The study analyzed that quality and design of product properties had significant effects on all factors, but the brand was not significantly affected. Second, while superiority, differentiation and scarcity of luxury items are significant to customer satisfaction but superiority is only significant in relation to recommendation intention. Third, the preceding study shows that the customer compensation program has a significant impact on sales growth, but the study found that it was not for imported luxury car customers. Fourth, if the royalties program is low in awareness, it has been analyzed that the scarcity and customer satisfaction relationships among luxury goods have been adjusted. On the contrary, if there is a high level of awareness, it is analyzed that there is a control effect customer satisfaction and differentiation among luxury brands. In the conclusion, in order to satisfy customers at the import luxury car market, the differentiation of luxury goods by standard index must be strengthened and the brand must be strengthened among the attributes of the product. In addition, by raising awareness of the royalties program, the relationship between differentiation and customer satisfaction can be enhanced.