• Journal of Magnetics
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• v.18 no.3
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• pp.342-347
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• 2013

Local wall thinning in pipelines affects the structural integrity of industries, such as nuclear power plants (NPPs). In the present study, a development of pulsed eddy current (PEC) technology that detects the wall thinning of pipelines covered with insulation is reviewed. The methods and experimental results, which have two kinds of probe with a single and double core, were compared. For this purpose, the single and double core probes having one and two excitation coils have been devised, and the differential probe with two Hall sensors has been fabricated to measure the wall thinning in insulated pipelines. The test sample is a stainless steel having different thickness, laminated by plastic insulation to simulate the pipelines in NPPs. The excitation coils in the probe is driven by a rectangular current pulse, the difference of two Hall sensors has been measured as a resultant PEC signal. The peak value of the detected signal is used to describe the wall thinning. The double core probe has better performance to detect the wall thinning covered with insulation; the single core probe can detect the wall thinning up to an insulation thickness of 18 mm, whereas the double probe can detect up to 25 mm. The results show that the double core PEC probe has the potential to detect the wall thinning in an insulated pipeline of the NPPs.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3406-3412
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• 2021

A real-time digital time-stamp sorting algorithm used in the In-Beam positron emission tomography (In-Beam PET) is presented. The algorithm is operated in the field programmable gate array (FPGA) and a small amount of registers, MUX and memory cells are used. It is developed for sorting the data of annihilation event from front-end circuits, so as to identify the coincidence events efficiently in a large amount of data. In the In-Beam PET, each annihilation event is detected by the detector array and digitized by the analog to digital converter (ADC) in Data Acquisition Unit (DAQU), with a resolution of 14 bits and sampling rate of 50 MS/s. Test and preliminary operation have been implemented, it can perform a sorting operation under the event count rate up to 1 MHz per channel, and support four channels in total, count rate up to 4 MHz. The performance of this algorithm has been verified by pulse generator and ²²Na radiation source, which can sort the events with chaotic order into chronological order completely. The application of this algorithm provides not only an efficient solution for selection of coincidence events, but also a design of electronic circuit with a small-scale structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.6
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• pp.481-488
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• 2021

The satellite telecommand processing system is the only way to provide telecommands for status monitoring, control, and mission execution. Domestic satellites can be divided into science, technology, and multi-purpose satellites, and geostationary satellites. These Satellites uses CCSDS standard protocol to communicate with ground stations. However, existing domestic satellites use only software to decode telecommands which increases cost of software development and verification of the developed software. Performance of software only approach is relatively low compared to hardware. In this paper, we present ASIC processing system specifically designed to decode telecommands. The system consists of a telecommand RAM, a protocol RAM/ROM, an ASIC, an interface unit of FPGA, and a relay block. The system handles general commands and pulse commands that are used in satellites. We established a ground station equipment and test environment to verify the system functionality, The result shows that our system reduces the development cost by 1/5 and improves the performance by 10⁵ times compared to the previous systems that decode telecommands only by software.

• Geomechanics and Engineering
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• v.25 no.1
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• pp.41-48
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• 2021

In cold regions, the integrity of the infrastructures built on weak soils can be extensively damaged by weathering actions due to the cyclic freezing and thawing. This damage can be mitigated by exploiting soil stabilization techniques. Generally, ordinary Portland cement (OPC) is the most commonly used binding material for investigating the chemo-hydromechanical behavior. However, due to the environmental issue of OPC producing a significant amount of carbon dioxide emission, calcium sulfoaluminate (CSA) cement can be used as one of the eco-sustainable alternatives. Although recently several studies have examined the strength development of CSA treated sand, no research has been concerned about CSA cement-stabilized sand affected by cyclic freeze and thaw. This study aims to conduct a comprehensive laboratory work to assess the effect of the cyclic freeze-thaw action on strength and durability of CSA cement-treated sand. For this purpose, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were performed on the stabilized soil specimens cured for 7 and 14 days which are subjected to 0, 1, 3, 5, and 7 freeze-thaw cycles. The test results show that the strength and durability index of the samples decrease with the increase of the freeze-thaw cycles. The loss of the strength and durability considerably decreases for all soil samples subjected to the freeze-thaw cycles. Overall, the use of CSA as a stabilizer for sandy soils would be an eco-friendly option to achieve sufficient strength and durability against the freeze-thaw action in cold regions.

• The Journal of Korean Medical History
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• v.32 no.1
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• pp.21-31
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• 2019

This study examines a Song-dynasty book entitled TaeYiKukZieKuaZungMun Kyuk (A Collection of Imperial Medical Service Examination Questions and Answers 太醫局諸科程文格), which is the collection of questions and answers in the state examinations on medicine. This book was compiled by Hah Dae-yim (何大任) who was the vice-principal of the TaeYiKuk (The Imperial Medical Service 太醫局). The book consists of nine chapters. The present study reviewed all the chapters and found a number of significant issues. First, test-takers were required to be highly proficient in the fundamental knowledge of canonic texts of East Asian medicine. Second, pulse diagnosis was emphasized among the four diagnostic methods (四診). Third, herbal medicine formulas are organized according to the fixed structures of Ki Bang (奇方), which contained an odd number of herbs and Wu Bang (偶方), which contained an even numbered herbs), and fixed ratios for mixing various herbs. Fourth, there is a theory for division of therapies in which acupuncture is used for meridian diseases and herbal medicine for organ diseases. Fifth, herbal medicine formulas based on Unki theory (運氣學) are simpler than those of the previous generations. Sixth, the knowledge on the place of origin of herbs was emphasized. Seventh, knowledge of the relationship between herbs was also emphasized. Eighth, Tang (湯) and San (散) were used most frequently as forms of medicine.

• Journal of Society of Preventive Korean Medicine
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• v.22 no.3
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• pp.61-72
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• 2018

Objectives : This study was conducted to review the research trends in Korean Medicine of pompholyx based on publications in Korea. Methods : Literature published after 2000 were collected using OASIS, NDSL, KISS, and key words searched were "한포진" "발한이상" "pompholyx" "dyshidrotic eczema". Results : 10 case reports and 4 patient studies were selected for study. Conclusions : Korean medicine treatments included acupuncture, pharmacopuncture, venesection therapy, herbal medicine, ointments and carbon arc lamp therapy. The most commonly used diagnostic method for pompholyx was inspection along with pulse diagnosis, abdominal diagnosis, tongue diagnosis, culture test, and KOH smear screening. The most frequently used treatment evaluation method was Likert scale while VAS(Visual Analog Scale) and Visual&Subjective symptoms were each used in 4 studies. Among 29 patients in 14 papers who showed clinical manifestations of pompholyx, there were 15 male patients (52%), 14 female patients (48%), and the male to female ratio showed 1.07:1. Symptoms were improved using Korean Medicine treatments including acupuncture and herbal medicine. Concurrent treatment using special treatments such as pharmacopuncture, jiyang-go, bojungikgi-tang(ex), external applications showed higher treatment effects. Korean medical treatment of pompholyx was effective in all studies, but the lack of numbers of research on Korean medicine of pompholyx was witnessed compared to other diseases such as psoriasis. Also considering the number of patients suffering from pompholyx, further studies should be conducted.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.99-105
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• 2018

This paper proposes multiple access method for smart doorlock system using VLC(Visible Light Communication) with color grid modulation method. The proposed method is to connect multiple visible light signals using color grid modulation method in order to recognize and authenticate multiple users accessing doorlock. In order to enable visible light multiple access with existing infrastructure, the symbol energy interval of signal should be maximized. Thus, performance of system in VLC channel is measured by modulating symbols based on the proposed method. We confirm the actual channel test results of the modulated signal to implement doorlock system that recognizes the number of multiple access users.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.9-14
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• 2019

A small millimeter-wave tracking radar is a pulse-based radar that searches, detects, and tracks a target in real time through a TWS (Track While Scan) method for a traps target on the sea with a large RCS running at low speed. It is necessary to develop a board equipped with a high-speed CPU to acquire and track target information through LPRF, DBS, and HRR signal processing techniques for a trap target operating various kinds of dexterous objects such as chaff and decoy, We designed a signal processor structure including DFT (Discrete Fourier Transform) module design that can perform real - time FFT operation using FPGA (Field Programmable Gate Array) and verified the signal processor implemented through performance test.

• Journal of Radiation Protection and Research
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• v.46 no.4
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• pp.194-203
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• 2021

Background: Surface soil radiation monitoring around nuclear facilities is important to classify and characterize the contaminated areas. A scanning and direct measurement technique can survey the sites rapidly before starting sampling analysis. Materials and Methods: Regarding this, we test and suggest a measurement technique for gross alpha/beta and ⁹⁰Sr activities in surface soil based on a mobile ZnS(Ag)/PVT (polyvinyltoluene) array and a handheld PVT rod, respectively. To detect ⁹⁰Sr selectively in soil mixed with naturally occurring radioactive materials, chosen energy channel counts from the multichannel analyzers were used instead of whole channel counts. Soil samples contaminated with exempt liquid ⁹⁰Sr with 1 Bq·g^-1, 3 Bq·g^-1, and 10 Bq·g^-1 were prepared and hardened by flocculation. Results and Discussion: The mobile ZnS(Ag)/PVT array could discriminate gross alpha, gross beta, and gamma radiation by the different pulse-shaped signal features of each sensor material. If the array is deployed on a vehicle, the scan minimum detectable concentration (MDC) range will be about 0.11-0.17 Bq·g^-1 at 18 km·h^-1 speed, highly sensitive to actual sites. The handheld PVT rod with 12 mm (Φ) × 20 mm (H) size can directly measure ⁹⁰Sr selectively if channels on which energies are from 1,470 and 2,279 keV are gated, minimizing crossdetection of other radionuclides. These methods were verified by measuring soil samples fabricated with homogeneous ⁹⁰Sr concentrations, showing static MDC of 2.16 Bq·g^-1 at a measurement time of 300 seconds. Conclusion: Based on the results, comprehensive procedures using these detectors are suggested to optimize soil sites survey.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.4
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• pp.295-304
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• 2022

Background: The first dental experience is vital in molding a child's attitude towards dentistry and dental outcomes. The cooperation of a child during dental treatment is essential to render successful and high-quality treatment. Dental anxiety is common in children undergoing dental treatment. The success of pediatric dental treatments and patient comfort depends on controlling the levels of patient anxiety in clinical settings. This study aimed to compare the effectiveness of the recorded maternal voice and virtual cognitive tool (Roogies application) in the management of pediatric dental patients. Methods: The study was carried out with children aged of 4-7 years [n = 80, (40 male and 40 female)], without any past dental history, and were randomly allocated into two groups. After informed consent was obtained, the entire procedure was explained to the parents. Anxiety was assessed pre-, during, and post-treatment by measuring pulse rate, and recording Venham Picture Test (VPT) scores. Group A [n = 40; 20 boys and 20 girls)] was provided with a headphone that played a recorded maternal voice. Group B [n = 40; 20 boys and 20 girls)] was administered the virtual cognitive tool. After conditioning the children, oral prophylaxis was performed for both groups. A comparative evaluation was conducted for each treatment session. Results: The intra-group comparison of VPT scores and heart rate for patients assigned to the recorded maternal voice showed a statistically significant difference in dental anxiety (P-value ≤0.001). Conclusion: This study demonstrated that a reduction in dental anxiety with the help of recorded maternal voice forms an important component of non-pharmacological behavior management. Alternatively, the use of a virtual cognitive tool as an anxiety-reducing technique can also be advocated.