• Laser Solutions
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• v.14 no.4
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• pp.21-27
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• 2011

In this work, we have studied on time-resolved transient reflective image of single crystalline Si surface after single-shot fs-laser irradiation with varying the laser fluence under two different laser spot sizes. The temporal profiles of transient reflectivity changes as well as its maximum values at the early delay time were found to be strongly dependent on both the laser beam spot size and laser fluence. We have interpreted the dependence of transient reflectivity changes on the laser spot size in terms of a relaxation of the generated free carriers to the bulk silicon, which should be interacted with the plasma.

• Journal of Korea Multimedia Society
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• v.24 no.7
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• pp.890-902
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• 2021

Although the object detection accuracy with still images has been significantly improved with the advance of deep learning techniques, the object detection problem with video data remains as a challenging problem due to the real-time requirement and accuracy drop with occlusion. In this research, we propose a method in pig detection for video monitoring environment. First, we determine a motion, from a video data obtained from a tilted-down-view camera, based on the average size of each pig at each location with the training data, and extract key frames based on the motion information. For each key frame, we then apply YOLO, which is known to have a superior trade-off between accuracy and execution speed among many deep learning-based object detectors, in order to get pig's bounding boxes. Finally, we merge the bounding boxes between consecutive key frames in order to reduce false positive and negative cases. Based on the experiment results with a video data set obtained from a pig farm, we confirmed that the pigs could be detected with an accuracy of 97% at a processing speed of 37fps.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.59-63
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• 2020

This study was conducted to investigate the relation between visual analogue scale and recovery time with type of injury that occur in elite wrestling athletes. The incidence rate of injury was analyzed the Poisson ratio, and the VAS and recovery time according to the type of injury were compared using the one-way ANOVA. In addition, the VAS and recovery time were examine the relationship using the Simple Linear Regression, and statistical significance level was α =.05. Injuries occurred most commonly in the ligament, followed by the muscle, cartilage and tendon.The VAS and recovery time according to the type of injury was statistically significant (p=.001, p=.001, respectively). The VAS and recovery time according to the type of injury was statistically significant (p=.001, p=.001). Also, increase in VAS of 1 point was associated with about 1.89 recovery time. These studies are expected to be useful as basic data for return to sports and safe training.

• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.189-193
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• 2003

A new algorithm is presented for adaptive notch filtering of narrow band or sine signals for embedded among broad band noise. The notch filter is implemented as a constrained infinite impulse response filter with a minimal number of parameters, Based on the recursive prediction error (RPE) method, the algorithm has the advantages of the fast convergence, accurate results and initial estimate of filter coefficient and its covariance is revealed. A convergence criterion is also developed. By using the information of the noise-to-signal power, the algorithm can self-adjust its initial filter coefficient estimate and its covariance to ensure convergence.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.259-266
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• 2017

The purpose of this study was to survey the effects of convergence factors and time elapsed after kidney transplantation on self-care adherence. The study included 235 patients; the data was collected from September, to October, 2014. Old age, female gender and duration of transplantation were identified as factors significantly affecting self-care adherence. Self-care adherence also showed significant differences depending on the elapsed time, and the decrease in self-care compliance was most evident between 1 and 5 years after kidney transplantation. Therefore, development of a nursing strategy that would provide education and self-care improvement programs is needed to improve self-care based on convergence factors and elapsed time.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.1-6
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• 2022

Real-time systems using web cralwing data must provide users with data from the same database as remote data. To do this, the web crawler repeatedly sends HTTP(HtypeText Transfer Protocol) requests to the remote server to see if the remote data has changed. This process causes network load on the crawling server and remote server, causing problems such as excessive traffic generation. To solve this problem, in this paper, based on user events, we propose a real-time web crawling technique that can reduce the overload of the network while securing the reliability of maintaining the sameness between the data of the crawling server and data from multiple remote locations. The proposed method performs a crawling process based on an event that requests unit data and list data. The results show that the proposed method can reduce the overhead of network traffic in existing web crawlers and secure data reliability. In the future, research on the convergence of event-based crawling and time-based crawling is required.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.425-434
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• 2022

Objectives: This study analyzes TVOC concentrations in root industry workplaces in order to prevent probable occupational disease among workers. Root industry includes all the infrastructure of manufacturing, such as casting and molding. Methods: Real-time TVOC sensors were deployed in three root industry workplaces. We measured TVOC concentrations with these sensors and analyzed the results using a data-analysis tool developed with Python 3.9. Results: During the study period, the mean of the TVOC concentrations remained in an acceptable range, 0.30, 2.15, and 1.63 ppm across three workplaces. However, TVOC concentrations increased significantly at specific times, with respective maximum values of 4.98, 28.35, and 26.65 ppm for the three workplaces. Moreover, the analysis of hourly TVOC concentrations showed that during working hours or night shifts TVOC concentrations increased significantly to higher than twice the daily mean values. These results were scrutinized through classical decomposition results and autocorrelation indices, where seasonal graphs of the corresponding classical decomposition results showed that TVOC concentrations increased at a specific time. Trend graphs showed that TVOC concentrations vary by day. Conclusions: Deploying a real-time TVOC sensor should be considered to reflect irregularly high TVOC concentrations in workplaces in the root industry. It is expected that the real-time TVOC sensor with the presented data analysis methodology can eradicate probable occupational diseases caused by detrimental gases.

• Progress in Medical Physics
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• v.33 no.4
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• pp.101-107
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• 2022

Purpose: Radiotherapy after bladder filling protocol (BFP) is known to enhance treatment quality and reduce side effects in prostate cancer, a common male solid cancer globally. However, due to the need to hold back urine during treatment, patients frequently complain of discomfort, and treatment is frequently suspended when patients urinate during treatment and urine penetrates the treatment device, causing malfunction. Therefore, the effect of minimizing treatment time when partial-arc volumetric modulated arc therapy (VMAT) was used instead of full-arc was assessed in this study. Methods: A total of 70 plans were created in 10 patients using 7 different arc sizes, and the treatment time for each plan was calculated. Results: Reduced arc size by half resulted in a 54.4% decrease in mean treatment duration, with a proportional tendency observed. Furthermore, the effect of VMAT arc size reduction on target dose homogeneity was significantly limited, and the effect on surrounding organs at risk (OAR) was negligible. It should be noted, however, that when the arc size decreases by >40%, the dose increases in the area without OAR around the target. Conclusions: The results of this study demonstrated that partial-arc VMAT for enhancing treatment convenience and efficacy of prostate cancer patients undergoing BFP can achieve a considerable reduction in treatment time while preserving treatment quality, and it is expected to be useful for partial-arc VMAT plan design and implementation in practice.

• Journal of Adhesion and Interface
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• v.20 no.1
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• pp.9-14
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• 2019

The change of three different reagents for electrical conductive paint using aircraft coating with elapsing time of exposure to different condition was investigated. Three different reagents were poured into the vial bottles, stored in air condition and room temperature and observed with elapsing days. In addition, adhesion property of paint was tried using cross cut tape test after storage of $N_2$ atmosphere. The weight of each different reagent was measured along with elapsing time. To confirm the change of chemical component with exposure of air atmosphere, FT-IR was performed. The weight of part A and Part B decreased slightly whereas the weight of part C decreased rapidly and the precipitation was remained. The part B was cured after exposure of $N_2$ atmosphere and the 2250 cm-1 from FT-IR peak decreased slowly at the same time. It was considered that the water contained in air accelerated the reaction of -NCO functional groups and it caused the curing whereas $N_2$ atmosphere not contained water and it resulted in the retardancy of curing.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.250-250
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• 2009