• Progress in Medical Physics
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• v.13 no.3
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• pp.109-113
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• 2002

In recent years, the radiotherapy equipment has become much more sophisticated, and with the complication comes an increased set of quality assurance (QA) responsibilities. Today's computer controlled linear accelerator requiring QA of not only the radiation integrity, but also the mechanical accuracy of the linear accelerator. The existing QA sheets are adequate for acceptance testing and commissioning but those sheets are somewhat descriptive form for routine QA. establishing the QA sheets for a facility are more efficient if the sheets could estimate the long-term stability for the result of QA. We are going to develope new prototype of mechanical QA sheet to visualize and to verify long-term stability of mechanical QA for clinical linear accelerator. The items included in mechanical QA sheet were 1) gantry rotation, 2) collimator rotation, 3) couch rotation, 4) optical distance indicator (ODI), and 5) laser alignment. We compared new prototype sheet with conventional sheet for several hospitals in Korea for those items. The QA acceptance criteria in this study mainly followed published recommendations. The contents of test for mechanical QA are the following. Confirm that the digital and/or mechanical gantry angle readouts are correct. Verify that digital and/or mechanical readouts of collimator angle agree with the true angle, as determined with the protractor. Measure the light field using a graph paper and compare with the digital readouts. Confirm digital readout accuracy. Verify that the sagittal laser, the left and right lasers, and the ceiling laser intersect at the isocenter. In the design of new QA sheet, we emphasized the representation of the long-term stability of mechanical QA by using Excel program. By using the new prototype QA sheet, we simplified and visualized the mechanical QA process, and could estimate the long-term stability of mechanical error of linear accelerator.

• Journal of Digital Convergence
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• v.10 no.5
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• pp.283-288
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• 2012

This study was undertaken to investigation the spray characteristics of the twin fluid atomization nozzle system. The light oil was injected at the normal temperature and injection pressure was 5 bar - 10 bar by 1 bar and volume flow was 0.5, 1.0 and 2,0 mmH2O(X10-2). We measured the SMD of sprayed droplet to study spray characteristics. The following conclusions were reached from the results of these study. 1. The more injection pressure increased, the more SMD decreased. 2. The more measuring distance between pressure nozzle tip and analyser beam increased, the more SMD increased. 3. SMD of the blower-air-added injection system were shown, increasing volume flow decreased respectively. The result of this study indicated the blower-air-added injection system induced beneficial changes in SMD. And it will be considered important indicator for spray characteristics design and performance evaluation of twin fluid atomization nozzle system.

• Journal of Korea Multimedia Society
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• v.21 no.2
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• pp.147-157
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• 2018

Alzheimer's disease has the significant factors for the both specific and characteristic features according to the disease progressing that are the volumetry and surface area by the brain hippocampus shrinking and thinning. However, we have suggested a shape analysis to calculate the variance by the roughness, coarseness or uneven surface on 3D MR images. For the reasons we have presented two methods: the first method is the distance calculation from major axis to edge points and the second method is the distance calculation from centroidal point to edge points on a coronal plane. Then we selected the shortest distance and the longest distance in each slice and analyzed the ANOVA and average distances. Consequently we obtained the available and great results by the longest distance of the axial and centroidal point. The results of average distances were 44.85(AD), 45.04(MCI) and 49.31(NC) from the axial points and 39.30(AD), 39.58(MCI) and 44.78(NC) from centroidal points respectively. Finally the distance variations for the easily recognized visualization were shown by the color mapping. This research could be provided an indicator of biomarkers that make diagnosis and prognosis the Alzheimer's diseases in the future.

• The Journal of Internal Korean Medicine
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• v.33 no.1
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• pp.1-13
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• 2012

Background : In oriental medicine, the status of the tongue is an important indicator to diagnose the condition of one's health, such as physiological and the clinicopathological changes of internal organs. A tongue diagnosis is not only convenient but also non-invasive, and therefore widely used in Oriental medicine. However, the tongue diagnosis is greatly affected by examination circumstances, patient's posture, and doctor's diagnosis criteria. Objectives : This study was designed to assure the necessity for standardization of tongue diagnosis based on diagnostic criteria of tongue coating thickness (TCT). Methods : Thirty tongue photographs were acquired and analyzed by digital tongue diagnosis system (DTDS) which measured the percentage of TCT on the tongue surface. Fifteen oriental medical doctors evaluated TCT in 30 photographs. Afterward, the 15 assessors were trained for diagnostic criteria of TCT and evaluated the photographs again. The intraclass correlation coefficient (ICC) was used to obtain the agreement rate among the 15 assessors and the agreement rate between assessors' TCT scores and DTDS values. Results : The agreement rate among the 15 assessors after training was higher than before training. The agreement rate between assessors' TCT scores and DTDS values after training was also higher than before training. Furthermore, the difference of the agreement rate between before and after training was significant (p<0.05). Conclusions : The standardization of diagnostic criteria of TCT increased the agreement rate among the assessors and the agreement rate between assessors' TCT scores and DTDS values. Therefore, the standardization of diagnostic criteria is expected to contribute to the objectification and quantification of the tongue diagnosis system.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.137-144
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• 2017

Recently, cyber resilience has emerged as an important concept, recognizing that there is no perfect security. However, domestic researches on cyber resilience are insufficient. In this study, the 22 indicators for cyber resilience assessment were initially developed by the literature survey and discussions with security experts. The developed indicators are reviewed using the Focus Group Interview method in terms of materiality and feasibility of the indicators. This study derived meaningful and useful indicators for the assessment of cyber resilience, and it is expected to be used as a foundation for the future cyber resilience studies. In order to generalize and apply the results of this study in practice, it is necessary to carry out quantitative researches in the future.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.27-37
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• 2017

Enrollment rate of childcare centers is an important indicator that regulates supply and demand of childcare services in South Korea, but monthly enrollment rate difference of childcare centers has not been studied. This study examines monthly enrollment rate difference from March 2015 to February 2016. Data for this study is drawn from the Korean Childcare Centers database and includes information about 39,775 childcare centers. Enrollment rate had increased steadily from 71.8% in March 2015 to 84.4% in January 2016, whereas it decreased by 50.3% in February 2016. The result showed that enrollment rate difference between March 2015 and January 2016 is about 13%p, and even those of between January and February 2016 is 32%p. Taken together, these findings suggest that the supply and demand of childcare services need to be regulated based on monthly enrollment information.

• Convergence Security Journal
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• v.20 no.3
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• pp.21-28
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• 2020

In recent years, hacking and malware techniques have evolved and become sophisticated and complex, and numerous cyber-attacks are constantly occurring in various fields. Among them, the most widely used route for compromise incidents such as information leakage and system destruction was found to be E-Mails. In particular, it is still difficult to detect and identify E-Mail APT attacks that employ zero-day vulnerabilities and social engineering hacking techniques by detecting signatures and conducting dynamic analysis only. Thus, there has been an increased demand for indicators of compromise (IOC) to identify the causes of malicious activities and quickly respond to similar compromise incidents by sharing the information. In this study, we propose a method of extracting various forensic artifacts required for detecting and investigating Hacking E-Mails, which account for large portion of damages in security incidents. To achieve this, we employed a digital forensic indicator method that was previously utilized to collect information of client-side incidents.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.1-11
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• 2011

It is time to review the direction of R&D investment which is the source of change in knowledge information ages. The DEA(Data Envelopment Analysis) is a efficient method by using the ratio of input and output elements. In this paper, we analyzed industry relationship and efficiency by DEA in order to analyze ripple effect of the regional industry technology development project. According to these results, we found the primary affected factor in performance of this project was human resource, and the turnover of participated company was not on the rise yet. On types of the project, we could find the efficiency quotient of critical technique development project was higher than of common technique development project because project period or budget scale infected to project performance. We expect the enhancement of technique developer, tenn and budget, and it is necessary the project results should lead performance such as sales force and employee growth.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.181-187
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• 2016

Typical Retro-reflectors installed on road have problems such as limiting a driver's visibility at night when it is foggy or rainy. On the other hand, LED illuminated studs, called cat's eye system, extends a driver's visibility under these conditions. In this paper, we present a design of the LED cat's eye system using solar energy that can sustain vehicles with about 30-ton weight and is compliant with the IP68 code for water proof as IEC standard 60529. In addition, we propose a scheme of designing a LED driving circuit consuming low power to take into accounts cold weather or rainy season with limited sunlight. This LED cat's eye studs is currently installed and used on expressway and bike route nationally as well as overseas.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.473-481
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• 2016

This study attempted to solve daily inconveniences and propose a direction for healthy skin care after investigating eating habits, preferred food and shower frequency and analyzing the relationship between these living habits and perceived skin dryness among adult men in their 30-40s who are suffering from pruritus due to dry skin. Most respondents revealed a high level of inconvenience in their daily lives because of dry skin. According to analysis of the correlation between these life habits and skin dryness, they had an effect on skin dryness in most categories of eating habits, preferred food and shower frequency. In particular, as the amount of smoking or preference for sweet food increased, skin dryness became more serious. Therefore, it appears it would be important to control the intake of preferred food and have healthy eating habits in that eating habits and smoking are correlated with skin health, and skin health is an indicator of physical health.