• International Journal of Highway Engineering
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• v.18 no.6
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• pp.35-40
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• 2016

OBJECTIVES : The objective of this study is to analyze the nonlinear behavior of block pavements using multi-load level falling weight deflectometer (FWD) deflections. METHODS : Recently, block pavements are employed not only in sidewalks, but also in roadways. For the application of block pavements in roadways, the structural capacities of subbase and subgrade are important factors that support the carry traffic load. Multi-load level FWD testing was conducted on block pavements to analyze their nonlinear behavior. The deflection ratio due to the increase in load was analyzed to estimate the nonlinearity of block pavements. Finite element method with nonlinear soil model was applied to simulate the actual nonlinear behavior of the block pavement under different levels of load. RESULTS : The results of the FWD testing show that the center deflections in block pavements are approximately ten times greater than that in asphalt pavements. The deflection ratios of the block pavement due to the increase in the load range from 1.2 to 1.5, indicating that the deflection increased by 20~50%. The material coefficients of the nonlinear soil model were determined by comparing the measured deflections with the predicted deflections using the finite element method. CONCLUSIONS : In this study, the nonlinear behavior of block pavements was reviewed using multi-load level FWD testing. The deflection ratio proposed in this study can estimate the nonlinearity of block pavements. The use of nonlinear soil model in subbase and subgrade increases the accuracy of predicting deflections in finite element method.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.20-27
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• 2009

This study aims to understand the consumer consciousness of the interior design by experiencing the interior space of the model house provided by the construction company. For this, the author investigated the spatial images about the apartment interior design and the satisfaction level depending on the experiential elements. Survey questionnaires were distributed to people who visited six model houses. Subjects were asked about the experience about the interior space of the model house. Their response to the experiential elements was analyzed with 5-point Likert scale and was computed as frequencies, percentages, and means. For the spatial image characteristics, adjectives were substituted for the image scales. As a result, the author found out the following: First, the interior space was commonly directed to the soft image, which was mixed with modern, noble, decent, dynamic and natural styles depending on the companies. The trend of each interior design basically had static, soft and vague images, and partially had two kinds of tendencies: the one was mild and natural, and the other was modern and elegant. Second, as the strategic modules of the experiential marketing, five experiential elements were investigated to find the satisfaction level through the model house interior space. The emotional element got the highest point followed by the cognitive element and the active element, while the sensible element and the relative element got the lowest point. Third, consumer response was generally positive toward the model house interior design provided by the construction company. It is necessary to make up for the design that can give an aesthetic pleasure with familiar images, rather than give a firm recognition about the design.

• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.518-529
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• 2012

The purpose of this study is to analyze the cognitive demands level of the description about 'element', 'periodic table', and 'atom' on the 'science 2' textbooks by the 2007 revised curriculum. The three types of CAT (Curriculum Analysis Taxonomy) have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science 2' textbooks. The cognitive demands level about 'elements' on many textbooks is a late concrete operational stage, because the descriptions of 'element' are pure substances or no more split into anything simpler substances. That cognitive demands level about one textbook is a early formal operational stage, because the descriptions 'element' are a substance of one kind of atom. The cognitive demands level of 'periodic table' on many textbooks is a late concrete operational stage, because the descriptions about 'periodic table' are the hierarchical classification for the categorizing reality. And the cognitive demands level of 'periodic table' is a early formal operational stage, because the descriptions about 'periodic table' are a collection of 'families' or two-way gradation of elements. That cognitive demands level about one textbook is a late formal operational stage, because the descriptions of 'periodic table' are a complex classificatory structure linking atomic structure. The cognitive demands level about 'atom' is a early formal operational stage because of the descriptions as "atoms have structure, some atoms are the same, or others are different".

• Fibers and Polymers
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• v.3 no.1
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• pp.31-37
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• 2002

Most fibers are irregular, and they are often subjected to combined loading conditions during processing and enduse. In this paper polyester and wool fibers under the combined tensile and torsional loads have been studied for the first time using the finite element method (FEM). The dimensional irregularities of these fibers are simulated with sine waves of different magnitude and frequency. The breaking load and breaking extension of the fibers at different twist or torsion levels are then calculated from the finite element model. The results indicate that twist and level of fiber irregularity have a major impact on the mechanical properties of the fiber and the effect of the frequency of irregularity is relatively small.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.393-399
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• 2011

An empirical formula proposed by Petersson and Plunt(PP's formula) and finite element analysis for impedance calculation of ship equipment foundations are investigated by comparing the analysis results with those of experimental results. The PP's formula well estimates resonant frequency of the foundations and impedance level except around the resonant region although the impedance level around the resonant frequency is heavily dependent upon the assumed loss factor. The results show that the PP's formula and finite element models can be complementarily used to estimate the impedance characteristics of various types of foundation of ships in design stage.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.22-25
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• 1999

A dynamic explicit finite element code for simulating sheet forming processes has been developed The code utilises the discrete Kirchhoff shell element and contact force is treated by a conventional penalty method. In order to reduce the computational cost a new and robust contact searching algorithm has been developed and implemented into the code. in the method a hierarchical structure of tool segments called a tree structure is built for each tool at the initial stage of the analysis Tree is built in a way to divide a trunk to 8 sub-trunk 2 in each direction until the lowest level of the tree(leaf) contains exactly one segment of the tool. In order to have a well-balanced tree each box on each sub level contains one eighth of the segments. Then at each time step contact line from a node comes out of the surface of the tool. Simulation of various sheet forming processes were performed to verify the validity of the developed code with main focus on he usefulness of the developed contact searching algorithm.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.8
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• pp.661-667
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• 2004

The characteristics of noise and vibration by a heavy impact source was studied. The triggering method was used for increasing the reliability and stability to measure the level of sound pressure. sound intensity and vibration acceleration. A simple finite element model and a rigid body analysis method were suggested to calculate the natural frequencies of the multi-layer floor system. The results show that the resilient materials decrease the natural frequency of the reinforced concrete slab, make a resonance with dominant driving frequency in the low frequency region, and increase the vibration and noise level. A simple finite element model and rigid body models was suggested to calculate the natural frequencies of the floor systems.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.538-550
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• 2006

XML Keyword search enables us to get information easily without knowledge of structure of documents and returns specific and useful partial document results instead of whole documents. Element level query processing makes it possible, but computational complexity, as the number of documents grows, increases significantly overhead costs. In this paper, we present document-level ranking scheme over XML documents which predicts results of element-level processing to reduce processing cost. To do this, we propose the notion of 'keyword proximity' - the correlation of keywords in a document that affects the results of element-level query processing using path information of occurrence nodes and their resemblances - for document ranking process. In benefit of document-centric view, it is possible to reduce processing time using ranked document list or filtering of low scored documents. Our experimental evaluation shows that document-level processing technique using ranked document list is effective and improves performance by the early termination for top-k query.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.4
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• pp.301-311
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• 2002

The purpose of this study was to compare the distributing pattern of stress on the finite element models with the different vertical bone level of implant fixture. The two kinds of finite element models were designed according to vertical bone level around fixture ($4.0mm{\times}11.5mm$). The cemented crowns for mandibular first and second molars were made. Three- dimensional finite element model was created with the components of the implant and surrounding bone. Vertical loads were applied with force of 200N distributed within 0.5mm radius circle from the center of central fossa and distance 2mm and 4 mm apart from the center of central fossa. Von-Mises stresses were recorded and compared in the supporting bone, fixtures, abutment screws, and crown. The results were as following : (1) In vertical loading at the center circle of central fossa on model 1 and 2, the difference from vertical bone in implant placement did not affect the stress pattern on all components of implant except for crown. (2) With offset distance incerasing and the bone level of implant decreasing, the concentration of stress occured in the buccal side of long crown, around the buccal crestal bone, and on the fixture- abutment interface. As a conclusion, the research showed a tendency to increase the stress on the supporting bone, fixture and screw under the offset loads when the vertical level of bone around fixture was different. Since the same vertical bone bed has more benefits than the different bone bed around fixtures, it is important to prepare a same vertical level of bone bed for the success of implants under occlusal loads.

• Journal of Information Technology and Architecture
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• v.11 no.3
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• pp.321-332
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• 2014

In this paper we propose a new notion of predictable flags type of authorization for controlling access to XML documents. By using predictable flags, we are able to efficiently detect conflicts between existing authorizations and new authorizations to be added. XML documents have an element-composition hierarchical structure in that a higher level element consists of multiple lower level sub-elements. Many XML documents systems have used the notion of implicit authorization that grants authorizations to an element and the all descendants to avoid the overhead caused by explicitly storing all authorization for each element. When we grant an authorization on an element in the XML documents, the implicit authorization method is inefficient in determining the conflicts since it needs to examine all authorizations on the descendants of that element. In contrast, our mechanism using predictable flags has the advantage of detecting the conflicts immediately at the element where an explicit authorization is to be granted.