• Geomechanics and Engineering
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• v.35 no.5
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• pp.475-486
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• 2023

Ballast particles have an irregular shape and are discrete in nature. Due to the discrete nature of ballast, it exhibits complex mechanical behaviour under loading conditions. The discrete element method (DEM) can model the behaviour of discrete particles under a multitude of loading conditions. DEM is used in this paper to simulate a series of three-dimensional direct shear tests in order to investigate the shear behaviour of railway ballast and its interaction at the microscopic level. Particle flow code in three dimension (PFC3D) models the irregular shape of ballast particles as clump particles. To investigate the influence of particle size distribution (PSD), real PSD of Indian railway ballast specification IRS:GE:1:2004, China high-speed rail (HSR) and French rail specifications are generated. PFC3D built-in linear contact model is used to simulate the interaction of ballast particles under various normal stresses, shearing rate and shear box sizes. The results indicate how shear resistance and volumetric changes in ballast assembly are affected by normal stress, shearing rate, PSD and shear box size. In addition to macroscopic behaviour, DEM represents the microscopic behaviour of ballast particles in the form of particle displacement at different stages of the shearing process.

• Journal of the Korean association of regional geographers
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• v.11 no.5
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• pp.474-487
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• 2005

This paper aims to provide empirical evidence required to describe the level of achievement by analyzing students' item response in NAEP implemented in the United States in 2001. The geography assessment in the NAEP is aimed to test students of 4th, 8th, and 12th grades, and consists of content dimension and cognitive dimension, The former includes 'space and place' 'environment and society' and 'spatial dynamics and connections,' and the latter includes 'knowing' 'understanding' and 'applying,' The level of achievement is defined as three levels for each grade: Basic, Proficient, and Advanced. In this paper, descriptions of achievement is derived inductively from an analysis of student's responses to the items which were selected by using item-mapping method. As a result, there is a great difference between the level of achievement derived empirically from students' response and the level of achievement designed principally suggested by the expert committee. The former could have a contribution to the improvement in geography curriculum.

• Journal of Periodontal and Implant Science
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• v.45 no.6
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• pp.216-222
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• 2015

Purpose: After extraction, the alveolar bone tends to undergo atrophy in three-dimensions. The amount of alveolar bone loss in the horizontal dimension has been reported to be greater than the amount of bone loss in the vertical dimension, and is most pronounced in the buccal aspect. The aim of this study was to monitor the predictive alveolar bone level following the extraction of anterior teeth seriously involved with advanced chronic periodontitis. Methods: This study included 25 patients with advanced chronic periodontitis, whose maxillary anterior teeth had been extracted due to extensive attachment loss more than one year before the study. Periapical radiographs were analyzed to assess the vertical level of alveolar bone surrounding the edentulous area. An imaginary line connecting the mesial and the distal ends of the alveolar crest facing the adjacent tooth was arbitrarily created. Several representative coordinates were established in the horizontal direction, and the vertical distance from the imaginary line to the alveolar crest was measured at each coordinate for each patient using image analysis software. Regression functions predicting the vertical level of the alveolar bone in the maxillary anterior edentulous area were identified for each patient. Results: The regression functions demonstrated a tendency to converge to parabolic shapes. The predicted maximum distance between the imaginary line and the alveolar bone calculated using the regression function was $1.43{\pm}0.65mm$. No significant differences were found between the expected and actual maximum distances. Likewise, the predicted and actual maximum horizontal distances did not show any significant differences. The distance from the alveolar bone crest to the imaginary lines was not influenced by the mesio-distal spans of the edentulous area. Conclusions: After extraction, the vertical level of the alveolar ridge increased to become closer to the reference line connecting the mesial and distal alveolar crests.

• Journal of the Korean Society of Costume
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• v.62 no.2
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• pp.26-39
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• 2012

This study intends to reconsider pleat, which was undermined as something too simple to express the details for women's costume, by focusing on the aesthetic value of plea in men's costumes in the west before the 20th century. Furthermore, based on the aesthetic value of the pleat, diverse studies on contemporary men's costumes shall help to attempt to set up a basis for the new mode of men's costume. The pleat, a component in the costume since the ancient times, had unique characteristics including functionality, a sense of volume, directing effect that is caused by line repetitions and formativeness that results through elasticity. First, the aesthetics of the pleat before the 20th century shows rhythmic sense through the repetition of the pleat line as shown in the drape type costume, and it also shows a sense of volume as the pleat is moved along the motion of the body. Second, it shows functionality as the expansion of space moves in accordance with the motion of body sets up an internal space of the costume that facilitates body motion. Third, the pleat extends two dimension space into three dimension space using its elasticity. It exaggerates specific parts of the costume while ignoring body shape in order to symbolize status and authority of men. Fourth, it unifies the costume by wrapping the body by using quadrangle cloths with drapers, and expanding the silhouette with the pleat artificially to conceal the physical character and personality of the wearer. The physical character of the wearer disappears into the space made by the pleat. The pleat reveals the voluptuous beauty within.

• Archives of design research
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• v.19 no.5 s.67
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• pp.293-302
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• 2006

Since the late 20C, the development of informative electronic technology has expanded human beings' spatial recognition from three-dimension into multi-dimension. Also space has formed mutual organic relation with the human being, since they started having the image responding ability of experience and recognition. The mutual organic relation has appeared in exhibition space aggressively introduced informative electronic technology from existing physical space. Therefore, m carried out a compartive study into the status of exhibition facilities and the form of interaction focusing on exhibition facilities as a medium of interaction between information and users in experiential exhibition space to which informative electronic technology had been introduced. The ultimate purpose of the study was that the phenomena, which had been anticipated from happenings in mutual organic relation between human beings and space, was reflected on space as a place of various communication activities. Hereafter, researches and studies on further exhibition should be continued to clarify the mutual relationship between exhibition space and user trends not only through exhibition space but also through the study of user trends that are changing everyday.

• Korea journal of population studies
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• v.31 no.2
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• pp.45-76
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• 2008

This study analyses the effect of gender on the support and control dimension of the relationship between adolescent children and their parents in 5 countries - Korea, Japan, U.S., Germany, and Sweden. This study predicts that mothers are more supportive and less controlling towards their children than fathers; that parents are more supportive towards their daughters than sons; and that supportive relationship is most pronounced in mother-daughter relations while controlling relationship is pronounced in father-son relations. We used the 2006 multi-national survey data collected by the National Youth Policy Institute for the analysis, selecting the cases in which the youth respondents were born between 1988 and 1993 and were living with both biological parents. All three hypotheses are supported in Korean cases. In the cases of the other nations, the hypotheses are only partially supported. In all the 5 nations, mothers are more supportive towards their children than are fathers. While parents are more supportive towards daughters than towards sons in most countries, the impact of children's gender in producing differences in parental behavior is less profound than the impact of parent's gender. Gender affects the control dimension of the relationship only in Korea and U.S.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.116-126
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• 2015

The purpose of this study is to analyze the change of programming strategies of chinese broadcasting as competitions intensify in the niche dimension. Specifically, the niche breadth which indicates the diversity of program genre and way of program production, the niche overlap which indicates the degree of competition among the channels, are investigated. The results show, as the competition has intensified, three chinese television pursued different programming strategies; CCTV1 maintained programming strategy without big change, while Hunan and Gangso pursued change of programming strategy. However the change of programming strategies of Hunan and Gangso showed different direction; Hunan has tended narrows niche breadth of program genre and the way of progrm production, while Gangso broadens niche breadth. In overall, Chinese broadcastings have found the way of co-exist pursuing different programming strategy. And the programming strategy of Gangso satellite broadcasting which broadens niche breadth has showed better performance in rating and advertising revenue.

• The Journal of Information Systems
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• v.29 no.3
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• pp.237-251
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• 2020

Purpose The research was studied the hierarchical Hangul emotion index by organizing all the emotions which SNS users are thinking. As a preliminary study by the researcher, the English-based Plutchick (1980)'s emotional standard was reinterpreted in Korean, and a hashtag with implicit meaning on SNS was studied. To build a multidimensional emotion dictionary and classify three-dimensional emotions, an emotion seed was selected for the composition of seven emotion sets, and an emotion word dictionary was constructed by collecting SNS hashtags derived from each emotion seed. We also want to explore the priority of each Hangul emotion index. Design/methodology/approach In the process of transforming the matrix through the vector process of words constituting the sentence, weights were extracted using TF-IDF (Term Frequency Inverse Document Frequency), and the dimension reduction technique of the matrix in the emotion set was NMF (Nonnegative Matrix Factorization) algorithm. The emotional dimension was solved by using the characteristic value of the emotional word. The cosine distance algorithm was used to measure the distance between vectors by measuring the similarity of emotion words in the emotion set. Findings Customer needs analysis is a force to read changes in emotions, and Korean emotion word research is the customer's needs. In addition, the ranking of the emotion words within the emotion set will be a special criterion for reading the depth of the emotion. The sentiment index study of this research believes that by providing companies with effective information for emotional marketing, new business opportunities will be expanded and valued. In addition, if the emotion dictionary is eventually connected to the emotional DNA of the product, it will be possible to define the "emotional DNA", which is a set of emotions that the product should have.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.235-245
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• 2012

The purpose of this paper is to develop an online analytical processing (OLAP) database system for small and medium-sized enterprises (SMEs) growth support. In this paper, we made a model of measuring SME size first. The model is composed of five determinants of firm growth such as employment, sales, the amount of export, own technology, and the ratio of R&D expenditure to sales. Second, we designed the FREQUENCY dimension table which will make staged support of R&D expenditure. We developed the OLAP database system by using three dimensions including the FREQUENCY dimension, and using the model of measuring SME size. Also we assessed past decisions on R&D expenditure support in the Small Business R&D Support Project by using the OLAP database system.

• The Journal of Advanced Prosthodontics
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• v.9 no.1
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• pp.38-44
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• 2017

PURPOSE. The objective of this study was to investigate the effect of surface treatments on microtensile bond strengths (MTBSs) of two types of indirect resin composites bonded to a conventional direct resin composite. MATERIALS AND METHODS. Indirect resin composite blocks of Ceramage and SR Nexco were prepared in a plastic mold having a dimension of $10{\times}10{\times}4\;mm$. These composite blocks were divided into three groups according to their surface treatments: Group1: Sandblast (SB); Group2: Sandblast and ultrasonically clean (SB+UL); Group3: Sandblast plus silane (SB+SI). After bonding with direct resin composite, indirect-direct resin composite blocks were kept in distilled water for 24 hours at $37^{\circ}C$ and cut into microbars with the dimension of $1{\times}1{\times}8\;mm$. Microbar specimens (n = 40 per group) were loaded using a universal testing machine. Failure modes and compositions were evaluated by SEM. The statistical analyses of MTBS were performed by two-way ANOVA and Dunnett's test at ${\alpha}=.05$. RESULTS. Surface treatments and brands had effects on the MTBS without an interaction between these two factors. For SR Nexco, the MTBSs of SB and SB+SI group were significantly higher than that of SB+UL. For Ceramage, the MTBSs of SB and SB+SI were significantly higher than that of SB+UL. The mean MTBS of the Ceramage specimens was significantly higher than that of SR Nexco for all surface treatments. CONCLUSION. Sandblasting with or without silane application could improve the bond strengths of repaired indirect resin composites to a conventional direct resin composite.