• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.421-431
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• 2002

C-shaped canal configuration is very difficult to treat because that clues about preoperative canal anatomy cannot be ascertained from clinical crown morphology and limited information can be derived from radiographic examination. This study was done to get more informations about the root and canal configuration of C-shape root by 3-dimensionally reconstructing for the purpose of enhancing success rate of endodontic treatment. 30 mandibular molars with C-shaped root were selected. Six photo images from occlusal, apical, mesial, distal, buccal, lingual directions and radiographic view were taken as preoperative ones to compare them with 3-D image. After crown reduction to the level of 1-2mm over pulpal floor was performed, teeth were stored in 5.25% sodium hypochlorite solution for the removal of pulp tissue and debris. They were cleaned under running water, allowed to bench dry and embedded in a self-curing resin. This resin block was serially ground with a microtome (Accutom-50, Struers, Denmark) and the image of each level was recorded by digital camera (FinePix S1-pro, Fuji Co., Japan). The thickness of each section was 0.25mm. Photographs of serial sections through all root canal were digitized using Adobe Photoshop 5.0 and then minimum thickness of open and closed sites were measured (open site is the surface containing occluso-apical groove closed site is oppsite). After dizitization using 3-D Doctor (Able software Corp, USA). 3D reconstruction of the outer surface of tooth and the inner surface of pulp space was made. Canal classsification of C-shaped roots was performed from this 3-D reconstructed image. The results were as follows : 1. Most C-shape rooted teeth showed lingual groove (28/30). 2 According to Vertuccis' calssification, type I, II, III, IV, VII were observed. but also new canal types suck as 2-3-2, 1-2-3-2. 2-3-2-1, 2-3-2-3 were shown. 3 There was little difference in minimum thickness on coronal and apical portions, but open site were thinner than closed site on mid portion. Conclusively, 3D reconstruction method could make the exact configurations of C-shape root possible to be visualized and analyzed from multi-directions. Data from minimum thickness recommend cleaning and shaping be more carefully done on dangerous mid portion.

• The Journal of the Korean dental association
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• v.55 no.2
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• pp.156-164
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• 2017

Purpose: The aim of this in vitro study was to assess changes in remineralization by stimulated human saliva over a short period of 48 hours with quantitative light-induced fluorescence (QLF) technology. Materials and Methods: Bovine incisor surfaces were demineralized for 10 days. Two types of stimulated saliva were collected from 7 healthy persons. 24 hours after tooth brushing (Stimulated saliva group) and immediately after tooth brushing with 1,000 ppm NaF dentifrice (Dentifrice saliva group). The specimens were immersed in saliva and fluorescence images were obtained by QLF-digital (QLF-D $biluminator^{TM}$,) at 2, 4, 6, 12, 24, and 48 hours fluorescence loss (${\Delta}F%$) of the lesions. A paired t-test was performed to assess fluorescence differences between before (${\Delta}F_{baseline}$) and after (${\Delta}F_{treatment\;time}$) the remineralization process. Results: Before the remineralization, the mean ${\Delta}F_{baseline}$ of the initial demineralized specimens was $-18.42{\pm}0.15$ (%). In both groups, the ${\Delta}F$ values obtained at baseline and after 2 hours were statistically significant (P < 0.001), indicating recovery of the lesions by approximately 40% after 2 hours. After 48 hours, remineralization rates were slightly higher (49%) for the stimulated saliva group than for the dentifrice saliva group (41%), but the difference was not statistically significant. Conclusions: With QLF minute degrees of remineralization by saliva can be measured in periods as short as 2 hours. Additionally no significantly higher effects of remineralization were observed in the dentifrice saliva group when compared to the stimulated saliva group.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.97-105
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• 2017

Purpose: The purpose of this study was comparing the efficacy of passive irrigation (PI) and passive ultrasonic irrigation (PUI) for ability to remove debriment of canals. Materials and Methods: Mandibular premolars were decoronated and standardized to 16 mm length. After root canal enlargement and half separating longitudinally, standardized groove of 4 mm length, 0.2 mm width and 0.5 mm depth were formed on the dentin wall of one half. Three depressions in the canal wall of the opposite half, 0.3 mm in diameter and 0.5 mm in depth, were formed. After each groove and depression was filled with dentin debris, two sections of each half were reassembled using impression putty material. In group 1 the canals were irrigated with 2.5% NaOCl by PI. In group 2 the canals were irrigated with 2.5% NaOCl by PUI. Before and after root canal irrigation, the root canal wall of the section was taken with a microscope and a digital camera as images. The amount of dentin debris remaining in grooves and depressions was assessed using a scoring system. Results: There was no significant difference between PI and PUI except for the middle 1/3 of the root canal (P = 0.004). Conclusion: At the middle 1/3 of the root canal, PUI removed more dentine debris than PI. But the removal efficiency of dentin debris is not significantly different between the PUI and PI at the apical area of root canal in mandibular premolars.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.745-756
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• 2020

An ICS(industrial control system) is a complex system that safely and efficiently monitors and controls industrial processes such as electric power, water treatment, transportation, automation plants and chemical plants. Because successful cyber attacks targeting ICS can lead to casualties or serious economic losses, it becomes a prime target of hacker groups sponsored by national state. Cyber campaigns such as Stuxnet, Industroyer and TRITON are real examples of successful ICS attacks, and were developed based on the deep knowledge of the target ICS. Therefore, for incident investigation of ICSs, inspectors also need knowledge of control processes and accident investigation techniques specialized for ICSs. Because there is no applicable technology, it is especially necessary to develop techniques and tools for embedded controllers located at cyber and physical boundaries. As the first step in this research, we reviewed logging capability of 4 PLC(Programmable Logic Controller)s widely used in an ICS area, and checked whether selected PLCs generate logs that can be used for digital investigation in the proposed cyber attack scenario.

• Progress in Medical Physics
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• v.14 no.3
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• pp.196-202
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• 2003

In 3-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), many studies on reducing setup error have been conducted in order to focus the irradiation on the tumors while sparing normal tissues as much as possible. As one of these efforts, we developed an image enhancement and registration tool for simulators and portal images that analyze setup errors in a quantitative manner. For setup verification, we used simulator (films and EC-L films (Kodak, USA) as portal images. In addition, digital-captured images during simulation, and digitally-reconstructed radiographs (DRR) can be used as reference images in the software, which is coded using IDL5.4 (Research Systems Inc., USA). To improve the poor contrast of portal images, histogram-equalization, and adaptive histogram equalization, CLAHE (contrast limited adaptive histogram equalization) was implemented in the software. For image registration between simulator and portal images, contours drawn on the simulator image were transferred into the portal image, and then aligned onto the same anatomical structures on the portal image. In conclusion, applying CLAHE considerably improved the contrast of portal images and also enabled the analysis of setup errors in a quantitative manner.

• The Journal of Korean Medicine
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• v.29 no.2
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• pp.107-115
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• 2008

Objectives: The objective of this study was to assess the effects of acupuncture applied at PC6 and SP4 points on heart rate variability (HRV) in normal subjects under mental stress Methods: 24 healthy male subjects were recruited and randomized to a treatment group (12 subjects) or a control group (12 subjects). Both groups performed a mental arithmetic stress test and then acupuncture needles were inserted on PC6 and SP4 for the study group. In the control group, they took sham acupuncture as a control. Heart rate variability (HRV) was measured during the whole study period by FM-150 (digital Holter ECG recorder). Results: In the both groups, low frequency (LF) power and ratio of low frequency to high frequency (LF/HF) was significantly increased after mental stress. Acupuncture induced significant decrease in low frequency (LF) power and ratio of low frequency to high frequency (LF/HF) which were increased after mental stress test. But sham acupuncture induced no changes. Results: In both groups, low frequency (LF) power and ratio of low frequency to high frequency (LF/HF) significantly increased after mental stress. Acupuncture induced significant decrease in low frequency (LF) power and ratio of low frequency to high frequency (LF/HF) which increased after mental stress test. In contrast, sham acupuncture induced no changes. Conclusions: Acupuncture on PC6 and SP4 could be useful to decrease sympathetic activity and balance autonomic nervous system for those who are under stress.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.284-287
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• 2000

Recently, developing medical devices have a tendency becoming the module for satisfying user's mutual complex needs. Because the most effective method for the observation of patients condition a diagnosis and a treatment is collecting data from various devices and controling operation following it. Module tendency is more popular due to manage easily totally many individual systems. This study implemented communication protocol to control by one control system connecting modular medical devices. Implemented system consist of one master module controlling all module and managing communication and many Slave modules. Communication between each modules introduced SPI(Serial Peripheral Interface) among many synchronous serial communication methods for the exact transmission and receipt of data. All communication executes by packet format. This can detect error. And, this protocol introduced PNP(Plug And Play) function that auto-detect connecting or removing module during running. This protocol exactly transmitted and received in faster speed more than 1Mbps. And in practical application to the ventilator this confirmed to give and take real-time data. And various functions by th central control system is implemented in this protocol.

• Journal of Technology Innovation
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• v.18 no.2
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• pp.59-89
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• 2010

One of the key words that represent the culture and social phenomena in this 21st century is 'Digital Convergence'. Presently our society is going through the second evolving phase of the convergence, integration between industries. Integration between industries refers to the phenomenon of integrating various industrial areas such as broadcasting, communication, finance, automobile, and medical treatment as the range of IT utilization becomes extended. The telecommunication-broadcasting bundling is a typical example of integration between industries. This study analyzed the effect of the service features of the bundling on the customer's acceptance intention by applying the innovative technology product acceptance model, TAM, in the process of accepting the telecommunication-broadcasting bundling. This study suggests three independent variables, the 'low cost(discount)', 'service integrity', and 'selectability', which affect perceived usefulness, perceived ease of use, and perceived risk, and figures out the actual influence as follows. In conclusion, these results suggest that in order to accept and spread the telecommunication-broadcasting bundling, it is necessary to establish (1) the cost discounting strategy realize (price strategy), (2) the fee noticing system, payment system, call-service system, and systemic integration including installation and A/S system integration, and develop (service strategy), (3) the bundling or related options that can provide users with selectability (product strategy).

• Korean journal of communication and information
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• v.80
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• pp.167-192
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• 2016

This study examined the social trauma experienced by direct victims of accidents and each member of the society affected by grand-scale disasters based on the concepts of collective unconsciousness, archetype, and individuation from Jung's analytical psychology, and their experience of therapy through media. For this purpose, the survivors of the disaster of Sewol that occurred on April 16, 2014, family of the deceased, psychological professionals, and general volunteers were selected as the subjects for one-on-one in-depth interviews and focus group interviews. The findings can be summarized as follows: first, the subjects are suffering from different forms of social trauma such as seclusion and anxiety due to primary/secondary incidents, but there is possibility for them to overcome the social trauma as a social community. Second, the archetypes of life and death, mourning and remembrance are showing in the subjects' everyday lives. In particular, it was found that various archetypes are appearing symbolically through the craft activities in which the survivors are participating most actively. Third, the media therapy program for the victims of the Sewol has limitations in various aspects. However, the fact that the craft activities that are not bound by time and space are highly effective manifests that anyone can take advantage of trauma therapy through digital media that are easily found around them. Finally, this study is significant as it verified the possible individuation of social trauma and identified the limitations of media therapy to suggest its development directions.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.36-43
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• 2020

The aim of this study was to assess the occlusal relationships of primary dentition of Korean preschool children in Hwaseong city. Total 444 children of age group between 2 and 5 years were selected. One pediatric dentist took intraoral photos of children. Evaluation and categorization of the primary molar relationships were done by single examiner. Statistical analysis was performed with Pearson chi-squared test. Total 389 samples, which is consisted of 185 boys, 204 girls were satisfied with inclusion criteria. Bilateral mesial step was seen in 61.7%. Bilateral flush terminal plane was seen in 15.4%. When the primary molar relations of the right and left sides were not the same, the combination of the mesial step and flush terminal plane was 14.7%. The present study provides insight into occlusal relationships in the primary dentition of 2 - 5 years old of Korean children in Hwaseong city. Pediatric dentists should understand occlusal relationships of primary dentition for establishment of appropriate treatment strategies and occlusal guidance.