• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.6
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• pp.389-397
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• 2015

Recently, wave propagation imaging based on laser scanning-generated elastic waves has been intensively used for nondestructive inspection. However, the proficiency of the conventional software based system reduces when the scan area is large since the processing time increases significantly due to unavoidable processor multitasking, where computing resources are shared with multiple processes. Hence, the field programmable gate array (FPGA) was introduced for a wave propagation imaging method in order to obtain extreme processing time reduction. An FPGA board was used for the design, implementing post-processing ultrasonic wave propagation imaging (UWPI). The results were compared with the conventional system and considerable improvement was observed, with at least 78% (scanning of $100{\times}100mm^2$ with 0.5 mm interval) to 87.5% (scanning of $200{\times}200mm^2$ with 0.5 mm interval) less processing time, strengthening the claim for the research. This new concept to implement FPGA technology into the UPI system will act as a break-through technology for full-scale automatic inspection.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.1
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• pp.119-130
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• 2004

The objective of this study was to develop a school uniform sizing system with high coverage rate for middle school boys, who are in the stage of rapid growth, by identifying problems in existing school uniform sizing systems through surveys of students and uniform manufacturing companies, and analyzing juveniles' physical sizes. For this purpose. the study conducted a survey about how middle school boys choose their uniform sizes, and what complaints they have on the size of the uniforms. In addition, it was investigated what is the current state of uniform manufacturing and sizing systems through a survey of uniform companies, and the study identified problems in the size of school uniforms by comparing physical sizes of juveniles' aged 14 to 16 with the sizing systems of the companies and KS standards in 1997. Juveniles' physical data was a part of the material of the national anthropometric data in 1997. Using the two-way distribution of juveniles' height-bust girth and height-waist girth, this study established the sizing system by increasing the number of sizes for the short interval where juveniles' physical sizes are densely distributed whereas limiting the number of sizes for the long interval where juveniles' physical sizes are rarely distributed, considering the difference between companies' standard and KS' standard.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.1036-1042
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• 2002

The purpose of this study was to set up the sizing system for clothes of lower body. Sample size was 191 females and their age ranges were from 19 to 24 years old. The lower body types for the sizing system were categorised by height and drop value of lower body(hip circumference-waist circumference). The results were as follows. 1. The Thick waist (drop value of lower body<21) and the Slender waist (drop value of lower body$\geq$27) had the low coverage rates of 14.2% and 11.5%, and the Normal waist (21$\leq$ drop value of lower body<27) had the high coverage rate of 72.8%. 2. The height could be divided into three groups and thar covered 97.5%. The Short(152cm) covered 2l.0%, the Regular(160cm) 58.7% and the Tall(168cm) 17.8%. 3. The size interval of hip circumference was 4cm and the intervals of waist circumference were 3cm and 4cm. The interval of slacks length was 4∼5cm according to three height groups.

• Journal of Multimedia Information System
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• v.5 no.2
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• pp.121-130
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• 2018

We developed multimedia esophageal catheters for use with birds to measure and record ECG and angular velocity while anesthesized, at rest, and in flight. These catheters enable estimates of blood pressure based on readings given by an angular velocity sensor and by RR intervals of ECG affected by EMG. In our experiments, the catheters had the following characteristics: 1. Esophageal catheters offer a topological advantage with 8-dB SNR improvement due to elimination of electromyography (EMG). 2. We observed a very strong correlation between blood pressure and the angular velocity of esophageal catheter axial rotation. 3. The impulse conduction pathway (Purkinje fibers) of the cardiac ventricle has a direction opposite to that of the mammalian pathway. 4. Sympathetic nerves predominate in flight, and RR interval variations are strongly suppressed. The electrophysiological data obtained by this study provided especially the state of the avian autonomic nervous system activity, so we can suspect individual's health condition. If the change of the RR interval was small, we can perform an isolation or screening from the group that prevent the pandemics of avian influenza. This catheter shall be useful to analysis an avian autonomic system, to perform a screening, and to make a positive policy against the massive infected avian influenza.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.5
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• pp.768-777
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• 2019

This study established a lower garment sizing system for elderly men over 65 years of age based on 535 males selected from the 5th Korean Anthropometric survey. The results are as follows. Most elderly men body measurements were smaller for adult males (except for the waist area); however, abdominal obesity has changed to body type. The standard deviation was applied around the average values of waist circumference and hip circumference for the suggestion of a lower garment sizing system for elderly men. The interval between the designation was ${\pm}2.5cm$ with an average waist circumference of 86 cm and ${\pm}2cm$ with an average hip circumference of 92 cm. A total of 13 designation sections were established in consideration of the cover ratio and cover efficiency. The cover ratio in the 13 nominal sections was 77.2%. The segmental distribution rate presented in the results will also be useful for production planning in specific sizes and enable rational production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.17-26
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• 2018

If a photovoltaic (PV) system is installed in a primary feeder interconnected with the PV system, bi-directional power flow can occur, and then, the magnitude and direction of the fault current can change, depending on the fault location and point of common coupling (PCC) of the PV system, and the time current curve (TCC) cannot be properly coordinated between protection devices. Also, it is difficult to obtain a proper time interval for protection devices because the conventional setting approach is applied, even though the PV system is installed and operating. Therefore, this paper presents three operation modes considering the operational conditions of the PV system to obtain setting values for protection devices. Based on the mode, this paper proposes an algorithm to calculate the optimal protection coordination time interval according to the introduction capacity of the PV system. In addition, this paper performs modelling of a distribution system with the PV system and protection devices by using Off-DAS S/W, and analyzes the characteristics of the time interval between the protection devices, such as substation relays, reclosers, customer relays, and PV customer relays. The simulation results confirmed that the proposed operational modes and setting-value algorithms are useful and effective for protection coordination in a distribution system for a PV system.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.39-50
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• 2001

Background: Power spectrum analysis method is a powerful noninvasive tool for quantifying autonomic nervous system activity. In this paper, we developed a data acquistion system for estimating the activity of the autonomic nervous system by the analysis of heart rate and respiratory rate variability using power spectrum analysis. Materials and methods: For the detection of QRS peak and measurement of respiratory rate from patient's ECG, we used low-pass filter and impedence method respectively. This system adopt an isolated power for patient's safety. In this system, two output signals can be obtained: R-R interval heart rate) and respiration rate time series. Experimental ranges are 30-240 BPM for ECG and 15-80 BPM for respiration. Results: The system can acquire two signals accurately both in the experimental test using simulator and in real clinical setting. Conclusion: The system developed in this paper is efficient for the acquisition of heart rate and respiration signals. This system will play a role in research area for improving our understanding of the pathophysiologic involvement of the autonomic nervous system in various disease states.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.596-603
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• 2018

The traffic congestion is frequently occurring due to increasing demand for vehicles and development of subcenter in roads of domestic-downtown. The design of a Great depth underground double-deck tunnel planned for construction as a solution however it's mainly for a compact-car. Its low height and small section cause causalities when fire occurs. From this study, the delay system for fire smoke diffusion is developed to minimize the occurrence of casualties when fire occurs in the Great depth underground double-deck tunnel and the CFD(Computational Fluid Dynamics) is used to find the optimal installation interval and the blockage ratio to maximize the system effects. The study analyzed the shorter the installation interval of the system, the higher the smoke delay effect but the efficiency-change tends to be slight above a certain distance and the larger the blockage ratio, the higher the effect but the efficiency-difference is slight according to installation interval.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12A
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• pp.1153-1160
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• 2005

OFDM/OQAM(Offset QAM)-IOTA system requires the IOTA(Isotropic Orthogonal Transform Algorithm) function that has superior localization property in time and frequency domain instead of guard interval used for conventional OFDM/QAM system to be robust to multipath channel. Therefore, OFDM/OQAM-IOTA system has more spectral efficiency than conventional OFDM/QAM system. But, when channel estimation scheme for conventional OFDM/QAM system is applied straightforwardly to OFDM/OQAM-IOTA system, an intrinsic Inter- symbol-Interference is observed. So suitable preamble structure for the channel estimation scheme of OFDM/OQAM-IOTA system is required. In this paper, we propose a new preamble structure that is appropriate to OPDM/OQAM-IOTA system and then perform ideal channel estimation and practical channel estimation in low-to-medium mobile speed and compare them with conventional OFDM/QAM system. Simulation results show that OFDM/OQAM-IOTA system with proposed preamble structure has 1.5 dB Eb/NO gain on Target BER $10^{-3}$ and about $25\%$ transmission rate gain against the conventional OFDM/QAM system considering quarter of FFT size as guard interval size.

• Journal of Korean Society for Quality Management
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• v.19 no.2
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• pp.78-85
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• 1991

In this paper, an inspection and replacement policy in a redundant system is considered. It is assumed that the state of the redundant system is known by inspection. When the system is inspected, it is preventively replaced only if the number of failed units exceeds the predetermined limit. Otherwise, the system is inspected after a inspection interval which depends on the number of failed units. We obtain the optimal number of redundant units, inspection intervals and replacement limit minimizing the expected cost rate.