• International Journal of Highway Engineering
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• v.18 no.3
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• pp.87-94
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• 2016

PURPOSES : This study analyzed the lane-by-lane traffic flow characteristics in Korea by using real-world data, including congestion levels, for 2-, 3-, and 4-lane freeways. METHODS : On the basis of a literature review, lane flow and speed characteristics were analyzed using flow measurements and speed ratios. In addition, the effect of congestion levels on traffic flow were visualized using rescaled cumulative plots. RESULTS : Driver behavior varied depending on the congestion level. During free-flow conditions, the lane-use ratio of individual lanes varied largely, whereas during congestion, the ratio was nearly the same for all lanes (i.e., equilibrium). During maximum-flow and congestion conditions, the median lane was used more than the shoulder lane, whereas during all other conditions, the shoulder lane had a higher lane-use ratio. In 3- or 4-lane freeways, the lane-use ratio of the median lane always exceeded 1 and was the highest during free-flow conditions. CONCLUSIONS : The results of the present analysis can be used as an index to predict congestion before a lane is overcapacitated. Moreover, the results can be applied in variable lane guidance systems, such as car navigation systems and variable message displays, to control traffic flow.

• Journal of Korea Multimedia Society
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• v.23 no.11
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• pp.1418-1427
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• 2020

The web has become indispensable in all of our daily lives. We communicate, study and get information with others through the web. This behavior also continues in the smart phone environment. The biggest problem is that the small display screen of a smart phone degrades the accuracy in selecting or manipulating content for people with low vision. To compensate for this, voice guidance services that combine touch and voice, such as VoiceOver and Talkback, are currently provided to smart phone devices. However, restrictions arise in GUI, TTS control problems, and content expansion and selection. In addition, unnecessary content is also output by voice, which causes fatigue for low vision people to use. In this study, we propose a mobile web browser interface that selects and enlarges a desired area from web browsers and contents, or outputs it as a voice so that people with low vision can easily use the mobile web browser. In this paper, we propose a context selective focusing function that enables selection for each element of web content. In addition, we intend to develop a mobile voice web browser that can enlarge the selected content or output it by voice.

• Journal of the Korean Society for information Management
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• v.26 no.4
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• pp.249-276
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• 2009

The purpose of this study is to investigate the information-seeking procedure of surveillants against public sector organizations in Korea. The surveillants used accountability mechanisms such as National Assembly Inspection and information disclosure to find out information they wanted. Examples of such group include social activists, professional supervisors, aides of the National Assembly congressman and the press members. Using data collected by in-depth interviews and participative observations, we studied their information seeking behaviors and factors that affect the procedure. Based on the Grounded Theory approach, we first generated 56 concepts, 17 categories and 6 super-categories about the participants' feeling, experiences and perception related to their information seeking. Then we developed a factor model among those generated concepts. The main contributions of this study are a) the results provide a useful guidance for the public information seekers b) we draw the requirements for enhancing public sector organizations' information management systems.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.113-119
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• 2018

The problem of poor learning has been a subject that has been constantly raised in the educational field since the mid 20th century. Therefore, this study classified the components of self - regulated learning into cognitive - control, motive - control, and behavior - control strategies, and examined the effects of self - regulated learning on internal value, self - efficacy, curiosity, and self - confidence. The study was conducted on university students who participated in the program for the study of depression in A university in Changwon city. The results showed that self - regulated learning factors had a positive effect on learning motivation. Second, the learning adjustment factors have a positive effect on self - efficacy. Finally, learning control factors have a positive effect on curiosity and self - confidence. Through this study, we confirmed that a comprehensive guidance system considering interaction is needed because various factors act integrally in the learning process. As a concrete method, it is imperative to develop a learning counseling program that can enhance the motivation level by referring to cognitive, synchronous, and behavioral factors.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.227-237
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• 2008

STATEMENT OF PROBLEM: Zirconium oxide can be a substitute to titanium as implant materials to solve the esthetic problems of dark color in the gingival portion of implant restorations. PURPOSE: This study was performed to define attachment and growth behavior of osteoblast- like cells cultured on grooved surfaces of zirconium oxide and evaluate the genetic effect of zirconium oxide surfaces using the reverse transcriptase-polymerase chain reaction (RT-PCR). MATERIAL AND METHODS: MC3T3-E1 cells were cultured on (1) commercially pure titanium discs with smooth surface (T group), (2) yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) with machined surface (ZS group), and (3) Y-TZP with $100{\mu}m$ grooves (ZG group). Cell proliferation activity was evaluated through MTT assay and cell morphology was examined by SEM. The mRNA expression of Runx2, alkaline phosphatase, osteocalcin, TGF-${\beta}1$, IGF-1, G3PDH in E1 cells were evaluated by RT-PCR. RESULTS: From the MTT assay, after 48 hours of adhesion of MC3T3-E1 cells, the mean optical density value of T group and ZG group significantly increased compared to the ZS group. SEM images of osteoblast-like cells showed that significantly more cells were observed to attach to the grooves and appeared to follow the direction of the grooves. After 24 hours of cell adhesion, more spreading and flattening of cells with active filopodia formation occurred. Results of RT-PCR suggest that T group, ZS group, and ZG group showed comparable osteoblast-specific gene expression after 24 hours of cell incubation. CONCLUSION: Surface topography and material of implants can play an important role in expression of osteoblast phenotype markers. Zirconia ceramic showed comparable biological responses of osteoblast-like cells with titanium during a short-time cell culture period. Also, grooves influence cell spreading and guide the cells to be aligned within surface grooves.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.279-285
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• 2017

This study was conducted based on the evaluation items of the Ministry of Culture, Sports and Tourism as an index. Based on the previous researches of various researchers, hypotheses were set up to survey the visitors who participated in the bamboo festival. As a result of the study, three factors of the festival service quality factors (hardware, promotion, guidance, and program) were studied through factor analysis. As a result of the study, it was confirmed that PR and. Also, the event program had a significant effect on the revisit inquiry of the festival at .446. The effect of festival satisfaction on repeat visits and recommendation results. Beta (${\beta}$) values were found to be correlated with return visit (.584) and recommendation (.651). We will present the factors that need to be maintained through the World Bamboo Expo and the Festival of Damyang, identify the visitors' needs to visit again, and suggest some suggestions for Daelim's tourism industry, the fourth industry and eco-industry.

• Human Ecology Research
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• v.53 no.2
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• pp.169-177
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• 2015

The PRQ instrument is parental perspectives of the parent-child relationship. It measured parent-child dimensions that include attachment and involvement. Also, it provides additional information on parenting style, parenting stress and satisfaction with the child's school. This study tested reliability and validity of the Korean version of Parenting Relationship Questionnaire-Child (K-PRQ-C). The K-PRQ-C was administered to parents of 713 elementary school children including 362 boys and 351 girls. They were from 1st to 6th grade children who were recruited form 4 elementary schools in Korea. Reliability was tested through internal consistency. We conducted confirmatory factor analysis. Moreover, scale inter-correlation was conducted for validity test. Discriminant validity conducted through administration to the parents of clinical children with emotional and behavior disorders. Construct validity was also examined through Korean version of the Parenting Sense of Competence. The results of confirmatory factor analysis indicated that the similar factor structures exist for PRQ-C and K-PRQ-C. The results showed a high level of internal consistency as well as construct and discriminant validity. These results showed valid psychometric properties for the K-PRQ-C. The K-PRQ-C provides a reliable and valid means of gathering information about the parent-child relationship. We discussed Implications for the use of the K-PRQ-C as a clinical tool and as a research instrument.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.69-74
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• 2003

Recent deepwater offshore structures in the Gulf of Mexico utilize butt welded tubular joints. Application of a welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical, as the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimation of the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves, as specified in the codes and standards. Applying the stress concentration factor of the welded structure to the S-N approach often results in a very conservative assessment, because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fatigue life analysis using fracture mechanics has been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. Still, there is inconsistency when designing tubular joints using a conventional S-N approach and when specifying weld flaw acceptance criteria using fracture mechanics approach. This study developed fatigue curves that are consistent with both the S-N approach and the fracture mechanics approach. Accounting for non-uniform stress distribution and threshold stress intensity factor were key parameters in relating both approaches. A series of S-N curves, generated from the fracture mechanics approach, were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02). The new curves for tubular joint agree very well with the experimental results. The comparison also indicated the degree of conservatism built into the API X design curve.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.61-68
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• 2010

The collapsing accidents of pipe greenhouses in the farmhouse have been increased duo to heavy snow load. However, the study on exact structure analysis to prevent the collapse of pipe greenhouses is rare and the damage of the farmhouse is annually repeated. The method of existing structure analysis is basically made of linear elastic analysis based on the micro displacement. But the actual stiffness of the pipe greenhouse is significantly weaker than the stiffness of buildings and the load acting on the greenhouses gets to become relatively bigger. It means that the geometry shape of greenhouses changes so that the relation of strain-displacement gets to indicate a nonlinear behavior. Therefore, this study is performed to evaluate the structural safety so as to prevent the collapse of pipe greenhouses, which are the single-span greenhouse(farmhouse guidance shape, G) and multi-span greenhouse(farmhouse supply shape, 1-2W), by performing the large-displacement analysis considering nonlinear effects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.8
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• pp.56-64
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• 2005

It is prerequisite that we have to fomulate the nonlinear mathematical modeling to design the guidance and control system of rotorcraft-based unmanned aerial vehicle using a small-scaled commercial helicopter. The small-scaled helicopters are very different from the full-scale helicopters in dynamic behavior such as high rotation speed and high frequency dynamic characteristics. In this paper, the formulation of the mathematical model of the small-scaled helicopter to minimize the complexity is presented by component and source build-up approach. It is linearized at the trim condition of hovering and forward flight and analyzed the flight modes. The results of this approach have general trends but a little difference. To verify this approach, it is necessary to compare this theoretical model with experimental results by system identification using flight test as a next research topic.