• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.164-165
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• 2006

• Progress in Medical Physics
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• v.12 no.2
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• pp.177-184
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• 2001

The goal of radiation treatment is to deliver a prescribed radiation dose to the target volume accurately while minimizing dose to normal tissues. Due to inaccurate placement of field and shielding block and patient's movement, there could be displacement errors between the planed and treatment regions. In order to verify the location of radiation treatment, we in this study developed the registration algorithm of the x-ray simulator images and portal images and quantified the inaccuracy in terms of shift, scale and rotation. The algorithm for registration of pairs of radiation fields consists of the alignment of pairs of radiation images by points matching and field displacement analysis by field boundary matching. In the first step, paired surface landmarks are matched to calculate the transformation parameters (scale, rotation and shift) using the corresponding line pairs which are created by connecting two landmarks of each image. In the next step, portal field boundary is extracted and then the two field boundaries are matched by the $\rho$-$\theta$ technique. Applying the phantom portal images, detection errors were calculated to be less than 2mm in translation, 1$^{\circ}$ in rotation and 1% in scale. In conclusion, we quantitatively analyzed the displacement error of x-ray simulator images and portal images. The present results could contribute to the study of the radiation treatment verification.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.76-84
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• 1997

At the initial design stage, for rapid evaluation of strength of ship structures, finite element analysis using beam elements is carried out in general. In beam modeling of ship structures, brackets are usually represented by rigid elements to simplify the analysis. Extent of rigid ends, which is called as a span point, can be determined from the three kinds of view points, i.e., bending, shearing and axial deformation. In this paper, a 2-dimensional novel beam element is developed and a method to replace the 3-dimensional analysis with 2-dimensional analysis is proposed. The developed novel beam element named rigid-ended beam element can consider the effect of three kinds of span points within one element, which was impossible in modeling with the ordinary beam element. Calculated results for the portal frame using the rigid-ended beam element agree with the results using membrane elements. And also, the proposed semi 3-dimensional analysis method which includes two step analysis using influence coefficients shows good accuracy. Structural analysis using the rigid-ended beam element and the semi 3-dimensional method is revealed to have good computing efficiency due to unnecessity of elements corresponding to the brackets and simplification of 3-dimensional analysis.

• Journal of Korean Library and Information Science Society
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• v.42 no.1
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• pp.325-338
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• 2011

This study aims to investigate characteristics of most clicked documents of Naver's universal search service. In particular, this study analyzed characteristics of most clicked documents such as click ratio, collection distribution, and yearly distribution. Also, clicked documents were evaluated in terms of relevance, credibility, and currency. In conducting this study, query logs and click logs of unified search service were analyzed. The results of this study show that most clicks occurred in blog collection and average click concentration rate reached almost 50%. Also, the relevance and currency of most clicked documents were quite high, but credibility of these documents were on average level. The results of this study can be implemented to the portal's effective development of searching algorithm and interface.

• International Journal of Advanced Culture Technology
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• v.4 no.2
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• pp.7-18
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• 2016

The first D2C-era web-real variety show in Korea was broadcast via tvN of CJ E&M. The web-real variety program 'SinSeoYuGi' accumulated 54 million views, along with 50 million views at the Chinese portal site QQ. This study carries out an analysis using text mining that extracts portal site blogs, twitter page views and associative terms. In addition, this study derives viewers' response by extracting key words with opinion mining techniques that divide positive words, neutral words and negative words through customer sentiment analysis. It is found that the success factors of the web-real variety were reduced in appearance fees and production cost, harmony between actual cast members and scenario characters, mobile TV programing, and pre-roll advertising. It is expected that web-real variety broadcasting will increase in value as web contents in the future, and be established as a new genre with the job of 'technical marketer' growing as well.

• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.281-290
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• 2003

A series of connection tests of portal frames which were composed of cold-formed steel studs and rafters was carried out to study the moment-rotation relation, the rotational rigidity, and the yield and the ultimate moment of the connections. The main factors of the tests were the thickness, the shape of the connecting members which were made of mild steel, and the torsional restraints of the test specimens. The test results were compared with those obtained through the non-linear analysis, for verification. The secant stiffness estimated from the experimental moment-rotation curve was proposed for the rotational rigidity of semi-rigid connections, and its validity was verified in the structural frame analysis.

• The Korean Journal of Health Service Management
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• v.13 no.1
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• pp.55-65
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• 2019

Objectives: The purpose of this study is to analyze basic data on socio - demographic characteristics, occupational careers, and desire for employment of job seekers in their Fifties and Sixties using a portal site. Methods: For this research, secondary data were collected by the researcher from 704 job seekers and were statistically analyzed using the SPSS package. Results: The results of the analysis are as follows: Most job seekers want a job that suits their competence and career trajectory, but the reality is that as their age increases, jobs suitable for those in their fifties and sixties are hard to find; thus these job seekers accept simple labor or functional jobs. Conclusions: Differences were found in work conditions such as occupation level, job position, total career years, desired employment type, and expected salary depending on socio - demographic variables. Consequently, improvements should be made for various job searching paths for older adults as well as increasing the accessibility of job searching information.

• Progress in Medical Physics
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• v.17 no.1
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• pp.24-31
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• 2006

Automated analysis software was developed to measure the magnitude of the intrafractional and interfractional errors during breast radiation treatments. Error analysis results are important for determining suitable planning target volumes (PTV) prior to Implementing breast-conserving 3-D conformal radiation treatment (CRT). The electrical portal imaging device (EPID) used for this study was a Portal Vision LC250 liquid-filled ionization detector (fast frame-averaging mode, 1.4 frames per second, 256X256 pixels). Twelve patients were imaged for a minimum of 7 treatment days. During each treatment day, an average of 8 to 9 images per field were acquired (dose rate of 400 MU/minute). We developed automated image analysis software to quantitatively analyze 2,931 images (encompassing 720 measurements). Standard deviations ($\sigma$) of intrafractional (breathing motion) and intefractional (setup uncertainty) errors were calculated. The PTV margin to include the clinical target volume (CTV) with 95% confidence level was calculated as $2\;(1.96\;{\sigma})$. To compensate for intra-fractional error (mainly due to breathing motion) the required PTV margin ranged from 2 mm to 4 mm. However, PTV margins compensating for intefractional error ranged from 7 mm to 31 mm. The total average error observed for 12 patients was 17 mm. The intefractional setup error ranged from 2 to 15 times larger than intrafractional errors associated with breathing motion. Prior to 3-D conformal radiation treatment or IMRT breast treatment, the magnitude of setup errors must be measured and properly incorporated into the PTV. To reduce large PTVs for breast IMRT or 3-D CRT, an image-guided system would be extremely valuable, if not required. EPID systems should incorporate automated analysis software as described in this report to process and take advantage of the large numbers of EPID images available for error analysis which will help Individual clinics arrive at an appropriate PTV for their practice. Such systems can also provide valuable patient monitoring information with minimal effort.

• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.177-183
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• 2022

This study investigated through eye tracking what gaze path the audience searches through portal sites (Naver, Daum, Zoom, and Nate). As a result of the layout analysis according to the gaze path of the search engine, the four main pages, which can be called to be the gateway to information search, appeared in the form of a Z-shaped layout. The news and search pages of each site use an F-shape, which means that when people's eyes move from top to right in an F-shape, they read while moving their eyes from left to right(LTR), which sequentially moves to the bottom. As a result of analyzing through the heat map, gaze plot, and cluster, which are the visual analysis indicators of eye tracking, the concentration of eyes on the photo and head copy was found the most in the heat map, and it can be said to be of high interest in the information. The flow of gaze flows downward from the top left to the right, and it can be seen that the cluster is most concentrated at the top of the portal site. The website designer should focus on improving the accessibility and readability of the information desired by the user in the layout design, and periodic interface changes are required by investigating and analyzing the tendencies and behavioral patterns of the main users.

• Journal of Industrial Convergence
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• v.20 no.12
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• pp.135-143
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• 2022

This paper aims to grasp what propensity users have in their ideology from the comments in the Web Portal News and the Press Website News. Through these analytical results, the political propensities of not only the Web Portal News and the Press Website News but also the voters who use these news media could be grasped. The collection of data necessary for this study has been made from the comments of 174 news stories for about 90 days before the election day. For the analysis, T-test has been used in order to compare Naver News with Daum News, the Minjoo Party of Korea with the People Power Party, and the Press Web Site News with Naver News. As a result of the analysis, the comments of Naver News took the higher percentage in the positive writings about the candidates of the conservative party. but, in contrast, those of Daum News in that percentage were higher about the ones of the progressive party. Accordingly, it can be found that Naver News is mainly used by users with the politically conservative propensity, while Daum News is mostly used by those with progressive one.