• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.163-170
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• 2018

This study was conducted to investigate the effects of noise from dental clinics on workers and to establish a reduction plan. The noise generated by the treatment instrument(Ultrasonic scaler, Hand piece, 3-way syringe, Suction, Compressor) was measured in order to determine the characteristics(level, frequency) of the noise during medical treatment(Oral prophylaxis, Conservation treatment, Prosthesis treatment, Implant Scaling, Tooth eliminating). We also assessed the noise levels in dental clinic using evaluation indicators such as NR-curves and NRN. The results of the analysis showed that the noise generated during the treatment was 85dB(A) ~ 70dB(A) and that the high frequency component was dominant, which would affect the workers working at the dental clinic. The NR-curve analysis showed NR-67 to NR-83 and the high frequency components of 4kHz to 8kHz were predominant and far exceeded noise levels in the workplace. To minimize the noise damage of workers and to provide high quality medical service, it is necessary to establish countermeasures such as wearing a soundproof and periodic hearing tests.

• Journal of Periodontal and Implant Science
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• v.48 no.6
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• pp.373-382
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• 2018

Purpose: The aim of this study was to evaluate the effects of various prophylactic treatments of titanium implants on bacterial biofilm formation, correlating surface modifications with the biofilms produced by Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and bacteria isolated from saliva. Methods: Pure titanium disks were treated with various prophylactic procedures, and atomic force microscopy (AFM) was used to determine the degree to which surface roughness was modified. To evaluate antibiofilm activity, we used P. aeruginosa PAO1, S. aureus, and saliva-isolated Streptococcus spp., Bacteroides fragilis, and Staphylococcus epidermidis. Results: AFM showed that the surface roughness increased after using the air-polishing device and ultrasonic scaler, while a significant reduction was observed after using a curette or polishing with Detartrine ZTM (DZ) abrasive paste. In addition, we only observed a significant (P<0.01) reduction in biofilm formation on the DZ-treated implant surfaces. Conclusion: In this study, both AFM and antibiofilm analyses indicated that using DZ abrasive paste could be considered as the prophylactic procedure of choice for managing peri-implant lesions and for therapy-resistant cases of periodontitis.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.629-636
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• 2022

We present a preprocessing method for an underwater target detection model based on a convolutional neural network. The acoustic characteristics of the ship show ambiguous expression due to the strong signal power of the low frequency. To solve this problem, we combine feature preprocessing methods with various feature scaling methods and spectrogram methods. Define a simple convolutional neural network model and train it to measure preprocessing performance. Through experiment, we found that the combination of log Mel-spectrogram and standardization and robust scaling methods gave the best classification performance.

• The Journal of Korean Physical Therapy
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• v.20 no.3
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• pp.45-51
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• 2008

Purpose: We evaluated the physical stress and pain to the musculoskeletal system of a dental practitioner when engaging in a dental scaling training exercise to prevent the development of musculoskeletal injuries. Methods: The 18 female (average age: 21$\pm$1 years) subjects were voluntarily picked from a group of juniors who have completed a one-and-a-half year training course that includes training exercises on the dentiform and on live subjects (other trainees). The test is done by measuring pain, activity, grip strength, and finger dexterity for each subject's hand and wrist. Before the test all subjects were confirmed to be right-handed and were informed of the study and its objective. Measuring was done before and after each subject performed dental scaling for one hour using the scaler and the curet. Results: Pain levels increased for both hand and shoulders, but hand pain was often greater than shoulder pain. Grip strength significantly declined in the right hand but not the left. For joint mobility, the flexion and the extension for the shoulder joint did not change; but the range of motion for both wrist joints significantly increased. For the dexterity test, both hands showed increased dexterity after the exercise. Conclusion: Dental scaling can affect the shoulders and wrists/hands. Therefore, a musculoskeletal injury prevention program for dental practitioners, which may include encouraging them to assume correct body posture when at work, must be sought. This study evaluated only the shoulders, wrists, and hands; but future studies should include areas such as the cervical area, the back, and the lower limbs.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.507-516
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• 2016

Objectives: The purpose of the study is to investigate the awareness and practice of dental unit waterline management in dental hygienist. Methods: A self-reported questionnaire was completed by 377 dental hygienists in Seoul and Gyeonggido from March 2 to April 30, 2015. The data were collected by direct visit and informed consent was received after explanation of the study. The questionnaire consisted of general characteristics of the subjects, awareness of dental waterline, practice of dental waterline, and implementation of dental waterline disinfection. Data were analyzed using SPSS 12.0 program. Results: There was a significant correlation between the dental unit waterline disinfection and the appropriateness of the water used for dental treatment(p<0.01, p<0.001). The handpiece was the most commonly used device before treatment and the majority of the subjects answered that they didn't take water out of ultrasonic scaler and air-water syringe on a daily basis. Conclusions: The majority of the dental hygienists did not know the right understanding and proper practice of dental unit waterline management. To reduce the dental device contamination, the continuing education of waterline management should be done for the dental hygienists.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.397-404
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• 2013

This paper propose the hardware architecture of face detection hardware system using the AdaBoost algorithm. The proposed structure of face detection hardware system is possible to work in 30frame per second and in real time. And the AdaBoost algorithm is adopted to learn and generate the characteristics of the face data by Matlab, and finally detected the face using this data. This paper describes the face detection hardware structure composed of image scaler, integral image extraction, face comparing, memory interface, data grouper and detected result display. The proposed circuit is so designed to process one point in one cycle that the prosed design can process full HD($1920{\times}1080$) image at 70MHz, which is approximate $2316087{\times}30$ cycle. Furthermore, This paper use the reducing the word length by Overflow to reduce memory size. and the proposed structure for face detection has been designed using Verilog HDL and modified in Mentor Graphics Modelsim. The proposed structure has been work on 45MHz operating frequency and use 74,757 LUT in FPGA Xilinx Virtex-5 XC5LX330.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.941-947
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• 2017

This paper reports a fractional-N phase-locked-loop(PLL) frequency synthesizer that is implemented in a $0.35-{\mu}m$ standard CMOS process and generates a quadrature signal for an FRS terminal. The synthesizer consists of a voltage-controlled oscillator(VCO), a charge pump(CP), loop filter(LF), a phase frequency detector(PFD), and a frequency divider. The VCO has been designed with an LC resonant circuit to provide better phase noise and power characteristics, and the CP is designed to be able to adjust the pumping current according to the PFD output. The frequency divider has been designed by a 16-divider pre-scaler and fractional-N divider based on the third delta-sigma modulator($3^{rd}$ DSM). The LF is a third-order RC filter. The measured results show that the proposed device has a dynamic frequency range of 460~510 MHz and -3.86 dBm radio-frequency output power. The phase noise of the output signal is -94.8 dBc/Hz, and the lock-in time is $300{\mu}s$.

• The Journal of the Korean dental association
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• v.53 no.9
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• pp.618-627
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• 2015

Purpose : The purpose of this clinical study was to evaluate the effect of chelating and deproteinizing agent containing dental conditioning gel on alleviation of peri-implant mucosa inflammation. Methods: 36 patients with functionally loaded implants for at least 1 year and have clinical signs of peri-implant mucositis were recruited. At baseline, all implants received subgingival prophylaxis with ultrasonic scaler. In the test group, patients were provided a chelating and deproteinizing agent dental conditioning gel (Clinplant$^{(R)}$) and were given instructions to applicate it around the implants using an interdental brush for 2 weeks. Chlorhexidine and saline were provided to the positive control group and negative control group, respectively. The modified sulcus bleeding index (mSBI), modified plaque index (mPI), and probing pocket depth (PPD) were evaluated at baseline, 1 week, and 2 weeks. Results: In the Clinplant$^{(R)}$ and chlorhexidine group, mSBI (-0.81, -0.85 respectively; p<0.01), mPI (-0.46, -0.5 respectively; p<0.01), and PPD (-0.58, -0.48 respectively; p<0.01) at 2 weeks were significantly reduced from baseline. In the saline group, all the clinical parameters were reduced but there was no statistical significance. The saline may be attributed to the influence of prophylaxis at baseline. Conclusions: The present study demonstrated the beneficial clinical effects of chelating and deproteinizing agent containing dental conditioning gel to decrease peri-implant mucosa inflammation equivalent to chlorhexidine. This dental conditioning gel might be useful for alleviation of peri-implant mucosa inflammation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.2
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• pp.33-44
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• 2010

This paper propose the structure of real-time face detection hardware architecture for robot vision processing applications. The proposed architecture is robust against illumination changes and operates at no less than 60 frames per second. It uses Modified Census Transform to obtain face characteristics robust against illumination changes. And the AdaBoost algorithm is adopted to learn and generate the characteristics of the face data, and finally detected the face using this data. This paper describes the face detection hardware structure composed of Memory Interface, Image Scaler, MCT Generator, Candidate Detector, Confidence Comparator, Position Resizer, Data Grouper, and Detected Result Display, and verification Result of Hardware Implementation with using Virtex5 LX330 FPGA of Xilinx. Verification result with using the images from a camera showed that maximum 32 faces per one frame can be detected at the speed of maximum 149 frame per second.

• Journal of Periodontal and Implant Science
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• v.42 no.6
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• pp.243-247
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• 2012

Purpose: The effects of magnetostrictive and piezoelectric devices on tooth surfaces seem to differ with regard to the root surface roughness they produce. This study aimed to compare the results of scaling using magnetostrictive and piezoelectric devices on extracted teeth. Methods: Forty-four human extracted teeth were assigned to four study groups (n=11). In two groups (C100 and C200), the teeth were scaled using a magnetostrictive device and two different lateral forces: 100 g and 200 g, respectively. In the other two groups (P100 and P200), the teeth were scaled with a piezoelectric device with 100 g and 200 g of lateral force, respectively. The teeth were scaled and the data on the duration of scaling and the amount of surface were collected and analyzed using the t-test. Results: The mean time needed for instrumentation for the piezoelectric and magnetostrictive devices was 50:54 and 41:10, respectively, but their difference was not statistically significant (P=0.171). For root surface roughness, we only found a statistically significantly poorer result for the C200 group in comparison to the P200 group (P=0.033). Conclusions: This study revealed that applying a piezoelectric scaler with 200 g of lateral force leaves smoother surfaces than a magnetostrictive device with the same lateral force.