• Radiation Oncology Journal
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• v.15 no.1
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• pp.71-78
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• 1997

Purpose : To collect beam data for dynamic wedge fields using conventional measurement tools without the multi-detector system, such as the linear diode detectors or ionization chambers. Materials and Methods : The accelerator CL 2100 C/D has two photon energies of 6MV and 15MV with dynamic wedge an91es of 15o, 30o, 45o and 60o. Wedge transmission factors, percentage depth doses(PDD's) and dose Profiles were measured. The measurements for wedge transmission factors are performed for field sizes ranging from $4\times4cm^2\;to\;20\times20cm^2$ in 1-2cm steps. Various rectangular field sizes are also measured for each photon energy of 6MV and 15MV, with the combination of each dynamic wedge angle of 15o 30o. 45o and 60o. These factors are compared to the calculated wedge factors using STT(Segmented Treatment Table) value. PDD's are measured with the film and the chamber in water Phantom for fixed square field. Converting parameters for film data to chamber data could be obtained from this procedure. The PDD's for dynamic wedged fields could be obtained from film dosimetry by using the converting parameters without using ionization chamber. Dose profiles are obtained from interpolation and STT weighted superposition of data through selected asymmetric static field measurement using ionization chamber. Results : The measured values of wedge transmission factors show good agreement to the calculated values The wedge factors of rectangular fields for constant V-field were equal to those of square fields The differences between open fields' PDDs and those from dynamic fields are insignificant. Dose profiles from superposition method showed acceptable range of accuracy(maximum 2% error) when we compare to those from film dosimetry. Conclusion : The results from this superposition method showed that commissionning of dynamic wedge could be done with conventional dosimetric tools such as Point detector system and film dosimetry winthin maximum 2% error range of accuracy.

• Therapeutic Science for Rehabilitation
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• v.13 no.2
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• pp.69-84
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• 2024

Objective : This study aimed to categorize the lifestyles of older adults into two types - healthy and unhealthy, and use machine learning to identify the personal values that influence these lifestyles. Methods : This cross-sectional study targeting middle-aged and older adults (55 years and above) living in local communities in South Korea. Data were collected from 300 participants through online surveys. Lifestyle types were dichotomized by the Yonsei Lifestyle Profile (YLP)-Active, Balanced, Connected, and Diverse (ABCD) responses using latent profile analysis. Personal value information was collected using YLP-Values (YLP-V) and analyzed using machine learning to identify the relative importance of personal values on lifestyle types. Results : The lifestyle of older adults was categorized into healthy (48.87%) and unhealthy (51.13%). These two types showed the most significant difference in social relationship characteristics. Among the machine learning models used in this study, the support vector machine showed the highest classification performance, achieving 96% accuracy and 95% area under the receiver operating characteristic (ROC) curve. The model indicated that individuals who prioritized a healthy diet, sought health information, and engaged in hobbies or cultural activities were more likely to have a healthy lifestyle. Conclusion : This study suggests the need to encourage the expansion of social networks among older adults. Furthermore, it highlights the necessity to comprehensively intervene in individuals' perceptions and values that primarily influence lifestyle adherence.

• Korean Journal of Social Welfare
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• v.66 no.3
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• pp.5-28
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• 2014

School absenteeism, one of the early warning signs of behavioral problems, has been known to be a complex and heterogeneous problem. However, much of the research assumes that school absentee adolescents comprise a homogeneous group. This study explored the heterogeneity of school absentee adolescents, based on school adaptation, to provide a more nuanced understanding of school absenteeism and examined predictive and risk factors associated with each typology of school absentee adolescents. Latent profile analysis was conducted using sample 477 middle school students who were reported absent in the previous year from the 3rd wave of Korean Children and Youth Panel Study. Multinomial logistic regression and ANOVA was also employed to examine the effects of predictive variables. As a result, three profiles were identified: low, middle, and high adaptive group. Group membership was found to be associated deferentially with gender, mental health, parenting neglect, delinquent friends, and delinquent behaviors. These findings propose more specific and targeted interventions designed to meet the needs and risk factors associated with the different typologies of school absentee adolescents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.803-813
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• 2013

As the developments of smart devices and social network services, the amount of data has been exploding. The world is facing Big data era. For these reasons, the Big data processing technology which is a new technology that can handle such data has attracted much attention. One of the most representative technologies is Hadoop. Hadoop Distributed File System(HDFS) designed to run on commercial Linux server is an open source framework and can store many terabytes of data. The initial version of Hadoop did not consider security because it only focused on efficient Big data processing. As the number of users rapidly increases, a lot of sensitive data including personal information were stored on HDFS. So Hadoop announced a new version that introduces Kerberos and token system in 2009. However, this system is vulnerable to the replay attack, impersonation attack and other attacks. In this paper, we analyze these vulnerabilities of HDFS security and propose a new protocol which complements these vulnerabilities and maintains the performance of Hadoop.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.205-214
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• 2013

The study of the compatibility of EPUB DRM, granted by the Korea Copyright Commission, as a CT R & D project (Project Title: Development of standard reference software technology for the International Standard EPUB-based eBook DRM) developed standards such as profile standards for encryption, digital signature and authentication certificates and standards for technical terms of rights information. In 2012, these four standards have been established as the Korean Industrial Standards under the names of 'Encryption specification for EPUB DRM', 'the Digital signature specification for EPUB DRM', 'the Certificate specification for EPUB DRM', and 'Definitions of Right Terms for EPUB DRM' through the ODPF(Open Digital Standardization Forum) and the TTA(Telecommunications Technology Association). In spite of the establishment of the eBook DRM standards, however, the absence of the standard technology which supports the compatibility for issues and changes of licenses makes it unable to use eBooks served by different eBook distributors. This study tries to investigate technological approaches to methods of license issues supporting eBook DRM compatibility on the basis of the above-mentioned four EPUB DRM standards and to provide an industrially accepted technological model.

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.575-587
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• 2020

Meteorological phenomena are observed by the Korea Meteorological Administration in a variety of ways (e.g., surface, upper-air, marine, ocean, and aviation). However, there are limits to the meteorological observation of the planetary boundary layer (PBL) that greatly affects human life. In particular, observations using a sonde or aircraft require significant observational costs in economic terms. Therefore, the goal of this study was to measure and analyze the meteorological factors of the vertical distribution of the see-land breeze among local meteorological phenomena using meteorological drones. To investigate the spatial distribution of the see-land breeze, a same integrated meteorological sensor was mounted on each drone at three different points (seaside, bottom of mountain, and mountainside), including the Boseong tall tower (BTT) at the Boseong Standard Weather Observatory (BSWO) in the Boseong region. Vertical profile observations for air temperature, relative humidity, wind direction, wind speed, and air pressure were conducted up to 400 m every 30 minutes from 1100 LST to 1800 LST on August 4, 2018. The spatial characteristics of meteorological phenomena for temperature, relative humidity, and atmospheric pressure were not shown at the four points. Strong winds (~8 m s-1) were observed from the midpoint (~100 m) at strong solar radiation hour, and in the afternoon the wind direction changed from the upper layer at the inland area to the west wind. It is expected that the analysis results of the lower atmospheric layer observed using the meteorological drone may help to improve the weather forecast more accurately.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.22-28
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• 2012

Vibrio parahaemolyticus is one of the major agents responsible for food poisoning during summer in Korea, which is transmitted via seawater or seafoods. Recently, distribution of the bacteria in the marine environment has been increased due to global warming. Great concern also has been raised regarding public hygiene as well as marine culture by the emergence of pathogens with antibiotic resistance. Therefore, distribution of V. parahaemolyticus and antibiotic resistance of the isolates were monitored in 7 coastal areas of Kyonggi Province and Incheon by sampling seawater, fishes and clams monthly. V. parahaemolyticus was detected from 47.7% of 966 samples (seawater 61.9%, seafoods 41.8%) analyzed using $CHROMagar^{TM}$ and TCBS agar plates as well as multiplex PCR. Among 13 antibiotics tested, resistance to vancomycin and ampicillin was observed in 97.3% and 87.3% of the isolates, respectively, and the ratios of them resistant to cephalothin (48.8%) and rifampin (46.1%) were also high. The isolates were most highly sensitive to chloramphenicol (91.7%) and trimethoprim-sulfamethoxazole (91.8%). The ratio of sensitivity for other antibiotics was also high in the descending order of gentamycin (82.3%), tobramycin (74.8%), nalidixic acid (71.6%), tetracyclin (69.4%), cefotaxime (63.0%). About 69% of the isolates showed multiple drug resistance toward 3 antibiotics including vancomycin and ampicillin. Two of them exhibited resistance for 11 antibiotics used in this study. Plasmid profile analysis of the isolates with antibiotic resistance revealed that 55.1% of them retained plasmids of 24 different types. However, no clear inter-relationship between the resistance and the plasmid profile has been observed.

• Restorative Dentistry and Endodontics
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• v.30 no.4
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• pp.294-302
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• 2005

The purpose of this study was to evaluate the canal configuration after shaping by ProFile. ProTaper and K-Flexofile in simulated resin canals with different angles of curvature. Three types of instruments were used: ProFile. ProTaper. K-Flexofile. Simulated root canals. which were made of epoxy resin. were prepared by ProFile. ProTaper with rotary instrument using a crown-down pressureless technique. and hand instrumentation was performed by K-Flexofile using a step-back technique. All simulated. canals were prepared up to size 25 file at end-point of preparation. Pre and post instrumentation images were recorded with Scanner. Assessment of canal shape was completed with Image Analysis program. Measurements were made at 1. 2. 3. 4. 5. 6. 7. 8. 9 and 10mm from the apex. At each level. outer canal width. inner canal width. total canal width. and amount of transportation from original axis were recorded. Instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA analysis of variance and the Sheffe's test. The result was that ProFile and ProTaper maintain original canal shape regardless of the increase of angle of curvature than K-Flexofile. ProFile show significantly less canal transportation and maintained original canal shape better than ProTaper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.38-47
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• 2019

The purpose of this study was to identify latent classes in executive function difficulty of first graders depends on evaluations from their mother and teacher and to investigate how its related with their school adaption and academic performance in second grade. Based on the model of the latent profile analysis, the 8th and 9th wave data from Korean Children and Youth Panel Survey were analyzed. The results of this study were as following. First, results showed that there were three types of latent classes in the executive function difficulty depend on evaluations from their mother and teacher: 'low executive function,' 'students who were highly evaluated by mother,' and 'students who were highly evaluated by teacher.' Second, students' executive function difficulty had a direct effect on the students' school adaption and academic performance in their second year of school. Especially students who were evaluated as having the lowest executive function difficulty showed significant higher means than students who were evaluated higher by mother and teacher. This study emphasized the importance of multiple evaluation in students' executive function difficulty to provide an educational intervention.

• Journal of the Korea Institute of Building Construction
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• v.20 no.6
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• pp.505-514
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• 2020

This research introduces the method of developing Korea BIM standard (KBIMS) architectural and structural element library and the methodology of converting KBIMS IFC property names with special characters. Diverse BIM tools are utilizing in project, however BIM library researches lack diversity on BIM tool selection. This research described the method to generate twelve categories and seven hundred and ninety-three elements library containing geometrical and numerical data in CATIA V6. KBIMS has its special property data naming systems which was the challenge inputting to ENOVIA IFC database. Three mapping methods for special naming characters had been developed and the ASCII code method was applied. In addition, the convertor prototype had been developed for searching and replacing the ASCII codes into the original KBIMS IFC property names. The methodology was verified by exporting 2,443 entities without data loss in the sample model conversion test. This research would provide a wider choice of BIM tool selection for applying KBIMS. Furthermore, the research would help on the reduction of data interoperability issues in projects. The developed library would be open to the public, however the continuous update and maintenance would be necessary.