• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.3
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• pp.21-30
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• 1986

A method for elasto-plastic analysis of grillages is proposed in this investigation. An effort to construct the stiffness matrix of the member with bending and torsional springs attached at both ends is made in this work to make each member of grillage behave elasto-plastically. A related computer program EPAG for elasto-plastic analysis of grillages is also developed. The characters of this program in comparison with existing methods are as fellows; grillage with arbitrary geometry can be analysed, collapse load is applied in one step instead of incremental procedure, unloading can be considered, and analysis results such as applied loads, member end forces and joint displacements are also obtained when individual plastic hinge is formed. For verification of performanse of the EPAG, illustrating examples are solved and compared with the results of specified literlatures.

• KSBB Journal
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• v.17 no.2
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• pp.158-161
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• 2002

In this study, a prototype fiber-optic biosensor was fabricated using the inhibition of enzyme reaction by organophosphorus compounds to detect organophosphorus compounds, which is nervous toxic material an? is used as chemical weapon and pesticide. Enzyme, substrate, and inhibitor for enzyme reaction were acetylcholinesterase (key enzyme in nervous cell), acetylthiocholine iodide, and paraoxon (a kind of organophosphorus compounds), respectively. The detection principle of sensor is the detection of enzyme reaction inhibited by organophosphorus compounds by the quantitative measurement of acetic acid, which was achieved by absorbance measurement using litmus solution that maximum absorbance band is changed by pH. To fabricate prototype fiber-optic biosensor, high bright LED and photodiode was used as light source and light intensity detector, respectively. From the experimental results using a prototype biosensor, the linear change of sensor signal was obtained in a range of 0-2 ppm inhibitor concentrations. From these results, it was verified that the quantitative measurement of organophosphorus compounds could be achieved fast (within 2 minutes) and accurately by a prototype fiber-optic biosensor.

• Journal of the Korea Society for Simulation
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• v.22 no.1
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• pp.63-75
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• 2013

The School Bus Routing Problem(SBRP) seeks to plan an efficient schedule of a fleet of school buses that must pick up student from various bus stops and deliver them by satisfying various constraints; maximum capacity of the bus, maximum riding time of students, arrival time between a school's time window. By extending the existing SBRP, we consider a case study of SBRP with allowance of mixed-loading and dynamic arrivals reflecting the school bus operation of university in Korea. Our solution procedure is based on constructing the initial solution using sweep algorithm and then improving solution within the framework of the evolutionary approach known as efficient meta-heuristics. By comparing the various scenarios through the constraints relaxation for reflecting the real operational strategies, we assess the merit of our proposed procedure.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.179-185
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• 2022

The purpose of this study is to provide new implications for the development and operation of programs and comparative studies in university policy by examining how core competencies of university students participating in tutoring programs affect learning satisfaction. For this purpose, 33 university students participated in the tutoring program before COVID-19 and 72 university students participated in the tutoring program after COVID-19 were surveyed and statistically processed. As a result, first, there was a positive correlation between self-innovation, challenge, communication, harmony, sincerity, problem solving and learning satisfaction among the components of core competencies of H university before COVID-19. There was a positive correlation between self-innovation, challenge, communication, harmony, sincerity, problem solving and learning satisfaction of core competencies after COVID-19. Second, in the pre-COVID-19 period, core competence had a high explanatory power on learning satisfaction, but there was no statistically significant factor in each of the remaining components except for the challenge. After COVID-19, core competence was secured with a high rate of explanatory power, self-innovation and harmony among the components of core competence were found to have a positive effect on learning satisfaction, and challenge was found to have a negative effect on learning satisfaction. The implications of this study are that when students participate in the tutoring program, it is necessary to emphasize the challenge factors and when they proceed in non-face-to-face, it is necessary to emphasize the self-innovation factors or the harmony factors rather than the challenge factors.

• Journal of The Korean Association of Information Education
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• v.21 no.1
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• pp.139-149
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• 2017

Artificial intelligence education is very important in the 21st century knowledge information society. Even if it is very important to understand artificial intelligence and practice computer programming in computer education in the fourth industrial revolution, but there is no teaching and learning model to understand artificial intelligence and computer programming education. In this paper, the proposed model consists of problem understanding step, data organizing step, artificial intelligence model setting step, programming step, and report writing step. At the program step, students can choose to copy, transform, create, and challenge steps to their level. In this study, the validity of the model was proved by the Delphi evaluation of elementary school teachers. The results of this study provide a good opportunity for elementary school students to practice artificial intelligence programs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.4
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• pp.385-392
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• 2009

Maritime safety management needs active public participations because the sea is too wide for a government to respond to all unexpected accidents with limited resources. Marine rescue volunteer organizations of US, UK, Japan and Korea were compared one another on the base of disaster management governance theory, and recommendations for the development of marine rescue volunteer organization of Korea were proposed. The advanced organizations commonly have tradition of marine rescue voluntaryism in the advanced maritime countries. They have nation-wide networks and self-governing structures. Their main activities include public maritime safety education and fundraising programs as well as marine rescue operations. They have cooperative relationships with government agencies in charge of national maritime safety management, which are usually guaranteed by legislations or institutional systems. Donations from the public are major source of their finances. Members mainly consist of civil volunteers, and get basic compensations for their expenses. For the advancement of marine rescue volunteer organization of Korea, efforts are needed to strengthen the membership of civil rescue fleet, to activate public education and fundraising programs, and to amend the related law for institutional support.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.2
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• pp.113-120
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• 1994

One of the delicate problems in aquifer management is the identification of the spatial distribution of tile hydrological parameters. The observed data are insufficient to identify the distribution of transmissivities in LAN aquifer. To determine the distribution of the transmissivity in LAN aquifer, it would be required to transform the observed heads at the pilot points into transmissivities. Therefore, three procedures wire tackled for the identification of the spatial distribution of the hydrological parameters; geostatistical estimate of the parameter field on the basis of known well point, heads reconstructed by a numerical model, and modification of the values at pilot points by a minimization algorithm. The variogram of Kriging has been applied to a total of 258 transmissivity value in attempt to quantify their distribution of LAN aquifer. Variogram of the observed and optimized transmissivities at pilot points are adapted to the exponential form. So, it is fitted by theoretical one with coefficients of w=0.623, a=2.743. Values of head obtained through numerical analysis are adjusted to the observed values so that heads have been transformed completely into the transmissivities at the observation wells. The procedure represented contour map of the estimated transmissivities and the calculated head.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3583-3589
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• 2010

The semi-implicit scheme proposed by Backhaus is introduced to solve two-dimensional shallow water equation. This mothod is applied for the numerical model solving surface elevation and velocity field of Geum River estuary. For the verification of the method, numerical solutions by this model are compared with ones by Heap's well known explicit model. Solutions of two models resemble each other. The time-step chosen for the semi-implicit scheme turned out to be 3 to 6 times longer than explicit model depending on the stringent CFL criterion. The computation time could be reduced at least 50%. It was proved that this scheme is easy to handle dry banks which can be seen in Geum River estuary and numerical stability is obtained for long time computation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.14-22
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• 2001

Off-line handwritten numeral recognition is a very difficult task and hard to achieve high recognition results using a single feature and a single classifier, since handwritten numerals contain many pattern variations which mostly depend upon individual writing styles. In this paper, we propose handwritten numeral recognition system using hybrid features and combined classifier. To improve recognition rate, we select mutually helpful features -directional features, crossing point feature and mesh features- and make throe new hybrid feature sets by using these features. These hybrid feature sets hold the local and global characteristics of input numeral images. And we implement combined classifier by combining three neural network classifiers to achieve high recognition rate, where fuzzy integral is used for multiple network fusion. In order to verify the performance of the proposed recognition system, experiments with the unconstrained handwritten numeral database of Concordia University, Canada were performed. As a result, our method has produced 97.85% of the recognition rate.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.1022-1031
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• 2002

This paper presents efficient models for bridge structures using CART-ANFIS (classification and regression tree-adaptive neuro fuzzy inference system). A fuzzy decision tree partitions the input space of a data set into mutually exclusive regions, each region is assigned a label, a value, or an action to characterize its data points. Fuzzy decision trees used for classification problems are often called fuzzy classification trees, and each terminal node contains a label that indicates the predicted class of a given feature vector. In the same vein, decision trees used for regression problems are often called fuzzy regression trees, and the terminal node labels may be constants or equations that specify the predicted output value of a given input vector. Note that CART can select relevant inputs and do tree partitioning of the input space, while ANFIS refines the regression and makes it continuous and smooth everywhere. Thus it can be seen that CART and ANFIS are complementary and their combination constitutes a solid approach to fuzzy modeling.