• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.213-223
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• 2006

Conventional truss optimization approaches, while often sophisticated and computationally intensive, have been applied to simple, minimum weight-cost models. These approaches do not perform well when applied to real-world trusses, which have costmodels that are complex and which often involve multiple objectives. Thus, this paper describes the optimization strategies that a clustering technique, which identifies members that are likely to have the same product type, uses for the optimal design of truss structures with real- world cost functions that consider the costs on the weight of the truss, the number of products in the design, the number of joints in the structures, and the costs required in the site.At first, the clustering technique is applied to identify the members and to generate a proper initial solution. A simple taboo search technique is then used, which attempts to generate the optimal solution by starting with the solution from the previous technique. For example, the proposed approach is a plied to a typical problem and to a problem similar to relative performances. The results show that this algorithm generates not only better-quality solutions but also more efficient ones

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.151-163
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• 2008

A formulation of three-dimensional model of articulated train-b ridge dynamic interaction has been made for the Korean eXpress Train (KTX). Semi-periodic profiles of rail irregularities consisting of elevation, alignment, cross and gauge irregularities have also been proposed using FRA maximum tolerable rail deviations. The effects of rail joints and sleeper step were also included. The resulting system matrices of train and bridge are very spare, and thus, are stored in one-dimensional arrays, yielding a time-efficient solution. A numerical algorithm for computing bridge-train response including an iterative scheme is also formulated. A program simulating train-bridge interaction and solving this problem using the new algorithm is implemented as new modules for the f inite element analysis software named XFINAS. Computed results using the new program are then checked by that of the validated 2-D bridge-train interaction model. This new 3D analysis provides more detailed train responses such as swaying, bouncing, rolling, pitching and yawing accelerations, which are useful inevaluating passenger riding comfort. Train operation safety and derailment could also be directly investigated by relative wheel displacements computed from this program.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.53-59
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• 2016

Recently, huge stream data have been generated in real time from various applications such as wireless sensor networks, Internet of Things services, and social network services. For this reason, to develop an efficient method have become one of significant issues in order to discover useful information from such data by processing and analyzing them and employing the information for better decision making. Since stream data are generated continuously and rapidly, there is a need to deal with them through the minimum access. In addition, an appropriate method is required to analyze stream data in resource limited environments where fast processing with low power consumption is necessary. To address this issue, the sliding window model has been proposed and researched. Meanwhile, one of data mining techniques for finding meaningful information from huge data, pattern mining extracts such information in pattern forms. Frequency-based traditional pattern mining can process only binary databases and treats items in the databases with the same importance. As a result, frequent pattern mining has a disadvantage that cannot reflect characteristics of real databases although it has played an essential role in the data mining field. From this aspect, high utility pattern mining has suggested for discovering more meaningful information from non-binary databases with the consideration of the characteristics and relative importance of items. General high utility pattern mining methods for static databases, however, are not suitable for handling stream data. To address this issue, sliding window based high utility pattern mining has been proposed for finding significant information from stream data in resource limited environments by considering their characteristics and processing them efficiently. In this paper, we conduct various experiments with datasets for performance evaluation of sliding window based high utility pattern mining algorithms and analyze experimental results, through which we study their characteristics and direction of improvement.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.13-20
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• 2009

Techniques for change detection using satellite images enable efficient detection of natural and artificial changes in use of land through multi-phase images. As for change detection, different results are made based on methods of calibration of satellite images, types of input data, and techniques in change analysis. Thus, an analytic technique that is appropriate to objectives of a study shall be applied as results are different based on diverse conditions even when an identical satellite and an identical image are used for change detection. In this study, Normalized Difference Vegetation Index (NDVI) and Principal Component Analysis (PCA) were conducted after geometric calibration of satellite images which went through absolute and relative radiometric calibrations and change detection analysis was conducted using Image Difference (ID) and Image Rationing (IR). As a result, ID-NDVI showed excellent accuracy in change detection related to vegetation. ID-PCA showed 90% of accuracy in all areas. IR-NDVI had 90% of accuracy while it was 70% and below as for paddies and dry fields${\rightarrow}$grassland. IR-PCA had excellent change detection over all areas.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.81-87
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• 2019

In this study, synthetic methods and physical properties for a new class of glycidyl azide polymer (GAP) were investigated for energetic thermoplastic elastomers (ETPE). Four kinds of GAP copolymer polyols were synthesized by introducing nucleophiles such as azide, alkoxide and alkyl amine into poly(epichlorohydrin) (PECH). The GAP copolymer synthetic reaction can be evaluated as an environmental benign and efficient synthetic method due to the simultaneous one-step reaction using two kinds of nucleophiles and the complete consumption of sodium azide. The relative stoichiometric substitution ratio analysis and the progress of reaction were checked and monitored by inverse gated decoupled $^{13}C$ NMR and Fourier transform infrared (FT-IR) spectroscopy. The glass transition temperature and molecular weight were measured by differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) analysis. The synthesized poly($GA_{0.8}-butoxide_{0.2}$), poly($GA_{0.7}-n-butylamine_{0.3}$), poly($GA_{0.7}-dipropylamine_{0.3}$) and poly($GA_{0.7}-morpholine_{0.3}$) had a glass transition temperature ranged from -39 to $-26^{\circ}C$.

• Communications of Mathematical Education
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• v.32 no.4
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• pp.495-517
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• 2018

This paper is based on the effects of Zone of Proximal Development and scaffolding theory of social constructivist, Russian psychologist Vygotsky. He insisted that a social interaction play a fundamental role in the development of cognition. This study is to examine the efficient of the scaffolding types in Math class. The ZPD is the distance between a student's ability to perform a task under adult guidances or with peer collaboration and the student's ability solving the problem independently. To conduct the research was grouped into an experimental first grader five students in H high school in Y county. After class, students were questioned through Semi-structured interviews. The results of this study are below. First, Students were satisfied with the class mixed micro-scaffolding types and Macro-scaffolding types and improved their math thinking ability and the ways of solving problems. Second, The results of the class showed that students' ability to perform a task was transferred to the higher level through the help of a teacher or peers. Students could have more time to listen to peers' opinions and to say their own thoughts freely than they were under the lecture method instruction. Third, Students were interested in math through the experimental class. That's because the appropriate help of the scaffolding type, a cooperate study, relative with real life, using an engineering tools. They made a change of perception.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.895-906
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• 2018

The improvement project for school zone in Korea is occurring mostly in kindergartens and elementary schools in which children are mainly active, and is being promoted as part of measures to prevent children's traffic accidents. However, since the study on the essential installation facilities and proper level of safety facilities for School zone is lacking, this study relatively evaluated the efficiency of safety facility installation using DEA (Data Envelope Analysis) and suggested improvement plan. We built the facilities and incident data for 28 school zones in Hwaseong City. Six major facilities (Raised intersection, Raised crosswalk, Protective fence, Skid Proof, Speed hump, Speed cameras) that have proven to be effective in the preceding research were analyzed as input factors. As a result of the analysis, only 12 out of 28 showed efficiency and 16 out of efficiency. Effective groups of school zones were found to have fewer installed Protective fences, Skid Proof, and Speed cameras installations than school zones classified as ineffective groups. Protective fences were found to be efficient even if only 47% of the total extension of the school zone was installed, and the number of slip prevention facilities was 8.7 per square km. The number of subjects to be compared is 28, so this study is limited to use as a relative efficiency evaluation index, and it can be grouped into nationwide units and efficiency evaluation can be done for each group.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.88-95
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• 2021

In Korea, which achieved economic growth due to export industries, the economic importance of the foreign port transportation industry is very great. The government took the initiative in fostering the foreign port transportation industry, and as a result, it developed into one of the top 10 foreign port transport countries in the world. However, due to the poor management of the small and medium-sized foreign port transport business and the trade dispute between countries, the foreign port transportation industry has faced a long-term invasion. Therefore, in order for these companies to recover again, they will, among other things, have to reorganize their operational inefficiency to carry out efficient production activities. In this study, we want to analyze the management efficiency of the top 10% companies in the unlisted domestic outbound shipping industry, present the project value of inefficient enterprises, and confirm the reference collection of companies that may be subject to benchmarking. For this purpose, a total of 10 foreign port transportation industry were analysed for efficiency and scale profitability (RTS) of the CCR and BCC models. The analysis showed that there were a total of six entities with BCC efficiency and five entities with CCR efficiency. In addition, there were a total of five entities with both BCC and CCR efficiency.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.173-183
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• 2020

In the midst of the aging of underground facilities in urban areas and anxiety about road excavation safety accidents, the Ministry of Land, Infrastructure and Transport began to build Underground Geospatial Infomation Map from 2015 as part of the 「ground subsidence prevention measures」 and efficient use of underground spaces. So, the scope is spreading every year. The current Underground Geospatial Infomation Map information is web-based and is operated in a desktop environment, so it is true that there are some limitations in its use in a field environment such as an excavation construction site. The Underground Geospatial Infomation Map, built and operated in a web-based environment, is a large-scale 3D data. Therefore, in order to service by transmitting data to the field without delay, it is necessary to lighten the Underground Geospatial Infomation Map data. In addition, the current Underground Geospatial Infomation Map is not unified in data formats such as 3DS and COLLADA, and the coordinate system method is also different in relative coordinates and absolute coordinates. In this study, by analyzing domestic and overseas prior research and technical use cases, a mobile Underground Geospatial Infomation Map data format and a lightweight method were presented, and a technology development was conducted to create a mobile underground space integration map in the presented format. In addition, the weight reduction rate was tested by applying 3D data compression technology so that data can be transmitted quickly in the field, and technology was developed that can be used by decompressing 3D data compressed in the field. finally, it aims to supplement the technology experimentally developed in this study and conduct additional research to produce it as software that can be used in the excavation site and use it.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.573-588
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• 2020

The study investigated the forest vegetation structure of Kongju National University Forests in the vicinity of Seokjangri-dong to provide the information needed for efficient use and management. It conducted a Z-M phytosociological vegetation survey in 60 quadrate plots in August 2019 and generated the actual vegetation map by analyzing the physiognomic community classification and mean importance value. The physiognomic community classification showed five vegetation community types: Quercus acutissima community, Pinus densiflora community, Quercus variabilis community, Pinus rigida community, and Quercus serrata community. The relative importance value in the Q. acutissima community was 31.4% for Q. acutissima, 9.6% for Prunus spp., and 9.0% for Q. variabilis. In the P. densiflora community, it was 24.9% for P. densiflora, 12.4% for Q. acutissima, and 11.5% for Q. serrata. In the Q. variabilis community, it was 25.3% for Q. variabilis, 9.8% for Prunus spp., and 8.5% for Q. acutissima. In the P. rigida community, it was 28.4% for P. rigida 28.4%, 10.0% for Q. acutissima, and 9.3% for P. densiflora. In the Q. serrata community, it was 27.0% for Q. serrata, 11.3% for Q. aliena, and 11.5% for Styrax japonica. The actual vegetation map based on the uppermost dominant species to identify the forest vegetation's spatial distribution characteristics indicated that the natural vegetation covered the most with 87.5%, the number of vegetation patches was 87, and the average area per patch was 1.46ha.