• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.418-426
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• 2021

This study investigates the perception of radiation safety management in radiation generator manufacturing workers and medical institutions. The basic data obtained is further applied to improve active coping ability and safety levels. The knowledge and attitude practice score of radiation was found to be related to gender, age, marital status, occupation, position, current work period, total work period, radiation related work period, the manual available, defense facility maintenance, number of defense equipment, radiation safety education, special health examination, and recognition of radiation terms. In particular, the knowledge score of radiologists was highest among the radiation-related occupations (<0.05). Radiation safety management requires active defense endeavors to prevent radiation exposure, by both workers of radiation manufacturers and medical institutions. Moreover, institutional devices such as compliance with guidelines, periodic education, facility reinforcement, manual preparation, and special health checkups are required for efficient radiation safety management.

• Journal of Oral Medicine and Pain
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• v.39 no.2
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• pp.35-45
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• 2014

Many therapeutic modalities including continuous positive airway pressure, surgery, and oral appliances are used to treat patients with sleep-disordered breathing. However, there are no definitive treatment modalities for individual patients due to various causes of sleep-disordered breathing. Clinicians should have select best options for individual patients and it is quite challenging process. Oral appliances attracted clinical attention for its convenience and safety. Several designs of oral appliances are introduces such as soft palate lifter, tongue retaining device, and various appliances which aimed to mandibular advancement. Among these oral appliances, mandibular advancement devices (MADs) are considered the most excellent based on their effectiveness and patient tolerance. Although MADs are not guarantee dramatic outcome and less consistent than continuous positive airway pressure, they offer several advantages over continuous positive airway pressure and surgical methods, including non-invasiveness, silence, portability, and tolerability, simplicity. Therefore, general dental practitioner who had passed sleep dental curriculum or coursework can treat the patients with sleep problems. This article reviews the history, clinical indications, suggested mechanism of actions, various positive effects and several side effects, factors predicting a favorable outcome, determining amounts of mandibular advancement, compliance and long-term efficacy of MADs use.

• Physical Therapy Korea
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• v.14 no.2
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• pp.29-36
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• 2007

Muscle tone (stiffness/hardness) or muscle compliance changes during muscle contraction. The purposes of this study were to assess the intrarater and interrater reliabilities of the Myotonometer$^{(R)}$, electronic device that quantifies muscle tone. Two raters used the Myotonometer to assess the right bicep brachia and quadriceps muscles of 30 voluntary persons without any orthopedic or neurological problems (age range, 18~21 yrs). Muscles were measured in a relaxed state and during brief sustained voluntary maximal isometric contraction. Intrarater correlation coefficients were calculated for each muscle and for each condition (relaxed and contracted). Intrarater reliabilities (intraclass correlation coefficients, ICCs) ranged from .778 to .954, relaxed, biceps brachia), .926 to .963 (contracted, biceps brachia), .935 to .990 (relaxed, quadriceps) and .679 to .952(contracted, quadriceps). Interrater reliabilities ranged from .652 to .790 (relaxed, biceps brachii), .813 to .907 (contracted, biceps brachii), .831 to .950 (relaxed, quadriceps) and .849 to .937 (contracted, quadriceps). Myotonometer measurements had high to very high intrarater and interrater reliability for measurements of the biceps brachia and quadriceps muscles.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.711-721
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• 2018

This paper presents a single-phase asymmetric half-bridge cascaded multilevel inverter based series active power filter (SAPF) for harmonic voltage compensation. The effect of level number on performance of the proposed SAPF is examined in terms of total harmonic distortion (THD) and system efficiency. Besides, the relationship between the level number and the number of switching device are compared with the other multilevel inverter topologies used in APF applications. The paper is also aimed to demonstrate the capability of the SAPF for compensating harmonic voltages alone, without using a passive power filter (PPF). To obtain the required output voltage, a new switching algorithm is developed. The proposed SAPF with levels of 7, 15 and 31 is used in both simulation and experimental studies and the harmonic voltages of the load connected to the point of common coupling (PCC) is compensated under two different loading conditions. Furthermore, very high system efficiency values such as 98.74% and 96.84% are measured in the experimental studies and all THD values are brought into compliance with the IEEE-519 Standard. As a result, by increasing the level number of the inverter, lower THD values can be obtained even under high harmonic distortion levels while system efficiency almost remains the same.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.578-583
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• 2006

This paper introduces conceptual design of scroll expander-compressor unit for fuel cell. Since air discharged out of the fuel cell stack after reaction has still high pressure energy, some power can be extracted out of it by directing it to pass through an expanding device so that the extracted power can be used to drive an auxiliary compressor. For this purpose, a scroll type expander coupled to a scroll type compressor was designed: orbiting scroll of the expander and that of the compressor were made to share three of common drive pins installed in the mid frame plate, and central cavity in the mid-plate was used as a back pressure chamber to provide axial compliance for both orbiting scrolls. Performance analysis for the expander showed that the shaft power of the expander could reduce the auxiliary power consumption in the fuel cell by about one third at the scroll clearance of $10{\mu}m$.

• Journal of Periodontal and Implant Science
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• v.45 no.2
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• pp.56-61
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• 2015

Purpose: The aim of this study was to evaluate the effectiveness of powered toothbrushes for plaque control in patients with peri-implant mucositis, in comparison with manual toothbrushes. Methods: This randomized, prospective, controlled, clinical parallel study compared the efficacy of manual and powered toothbrushes for plaque control in implant restorations. Patients with bleeding on probing, no residual pocket depth (as indicated by a pocket probing depth ${\geq}5mm$), and no radiological peri-implant bone loss were eligible for this study. Patients were requested to complete a questionnaire describing their oral hygiene habits. The duration and frequency of tooth brushing were recorded by subjects in order to assess their compliance. Clinical parameters, including the modified plaque index (mPI), the modified sulcus bleeding index (mSBI), and clinical photographs (buccal and lingual views) were recorded at baseline and at one-month and two-month follow-up visits. Results: Statistically significant differences between patients who used manual toothbrushes and those who used powered toothbrushes were found regarding the frequency of tooth brushing per day and the duration of brushing at one-month and two-month follow-up visits, while no statistically significant differences were found relating to other oral hygiene habits. A statistically significant difference in patient compliance for tooth brushing was found at one month, while no difference was found at two months. Statistically significant decreases in the mPI and the mSBI were observed in both groups from baseline to the one- and two-month follow-ups. The overall reduction of these parameters was not significantly different between the two groups, except for mPI reduction between baseline and one month of follow-up. Conclusions: Sonic-powered toothbrushes may be a useful device for plaque control in patients with peri-implant mucositis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1081-1090
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• 2010

$0.18{\mu}m$ CMOS UHF RFID tag frontend is presented in this paper. Several key components are highlighted: the voltage multiplier based on the threshold voltage terminated circuit, the demodulator using current mode, and the clock generator. For standard compliance, all designed components are under the EPC Global Class-1 Generation-2 UHF RFID protocol. Backscatter modulation uses the pulse width modulation scheme. Overall performance of the proposed tag chip was verified with the evaluation board. Prototype Tag Chip dimension is neary 0.77mm2 ; According to the simulation results, the reader can successfully interrogate the tag within 1.5m. where the tag consumes the power about $71{\mu}W$.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.74-82
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• 2015

As the complexity of an electronic device and the reduction of its operating voltage is progressing, susceptibility test of the chip and module for internal or external noises is essential. Although the immunity compliance of the chip was served with IEC 62132-4 Direct Power Injection method as an industry standard, in fact, EM immunity of the chip is influenced by their Power Domain Network (PDN). This paper evaluates the EM noise tolerance of a PLL and compares their noise transfer characteristics to the PLL on various PCB boards. To make differences of the PDNs of PCBs, various PCBs with or without LDO and with several types of capacitors are tested. For evaluation of discrepancies between EM characteristics of an IC only and the IC on real boards, the analysis of the noise transfer characteristics according to the PDNs shows that it gives important information for the design having robust EM characteristics. DPI measurement results show that greatly improved immunity of the PLL in the low-frequency region according to using the LDO and a frequency change of the PLL according to the DPI could also check with TEM cell measurement spectrum.

• Journal of Pharmaceutical Investigation
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• v.25 no.2
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• pp.109-116
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• 1995

For the administration of narcotic antagonist with short half-life and low patient compliance, the sustained release system using biodegradable matrix is effective. Polyphosphazenes are of considerable interest as biodegradable matrix systems for controlled release of drugs. In this study, biodegradable polyphosphazenes available for the sustained release implantable device were synthesized, and their application was examined. Poly[dichlorophosphazene] was synthesized by solution polymerization method and confirmed with IR spectrum. Poly[bis(ethyl glycinate) phosphazene] and poly[ (diethyl glutamate)-co-(ethyl glycinate)phosphazene] were then produced by substitution of amino acid alkyl esters for chloride side groups. Using these polymers, the implantable devices of 1 mm thickness and $10{\times}10\;mm$ size containing naloxone hydrochloride were prepared and their release and degradation profiles were measured. In the case of poly[bis(ethyl glycinate)phosphazene] with swelling characteristics, degradation rate was slower than the release rate, showing that the release rate is partly dependent on the swelling rate. In contrast, the degradation rate of polyl[(diethyl glutamate)-co-(ethyl glycinate)phosphazene] matrix was identical with release rate of naloxone hydrochloride. On the basis of these results, it is expected that these polymers can be applied to sustained release implantable systems delivering narcotic antagonist.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.92-101
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• 2003

The accessibility evaluation of ten web-based loaming content in Korea was performed with the following procedure : (1) A primitive metric of the compliance of those contents to the WCAG (Web Content Accessibility Guidelines) 1.0 was obtained using Bobby, a widely used accessibility checker. (2) SGML validation test was carried out. (3) The contents were rendered with various browsers including a text-mode browser. (4) They were manually checked as to whether they satisfy the accessibility criteria proposed by W3C. Most of the tested contents scored low marks in all the test categories partly because they were apparently developed with little attention paid to web standard conformance, browser compatibility, and device-independence. They also put heavy emphasis on audio-visual effects catering only to the best-equipped users and offering no alternate access route for those in restricted environment. As more information and learning materials are delivered through the Internet, these low accessible contents would lead to a deeper information divide. The accessibility needs to be regarded as an important factor in evaluating the quality of loaming content.