• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.583-592
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• 2011

The radiological characteristics for waste classification were assessed for neutron-activated decommissioning wastes from a CANDU reactor. The MCNP/ORIGEN2 code system was used for the source term analysis. The neutron flux and activation cross-section library for each structural component generated by MCNP simulation were used in the radionuclide buildup calculation in ORIGEN2. The specific activities of the relevant radionuclides in the activated metal waste were compared with the specified limits of the specific activities listed in the Korean standard and 10 CFR 61. The time-average full-core model of Wolsong Unit 1 was used as the neutron source for activation of in-core and ex-core structural components. The approximated levels of the neutron flux and cross-section, irradiated fuel composition, and a geometry simplification revealing good reliability in a previous study were used in the source term calculation as well. The results revealed the radioactivity, decay heat, hazard index, mass, and solid volume for the activated decommissioning waste to be $1.04{\times}10^{16}$ Bq, $2.09{\times}10^3$ W, $5.31{\times}10^{14}\;m^3$-water, $4.69{\times}10^5$ kg, and $7.38{\times}10^1\;m^3$, respectively. According to both Korean and US standards, the activated waste of the pressure tubes, calandria tubes, reactivity devices, and reactivity device supporters was greater than Class C, which should be disposed of in a deep geological disposal repository, whereas the side structural components were classified as low- and intermediate-level waste, which can be disposed of in a land disposal repository. Finally, this study confirmed that, regardless of the cooling time of the waste, 15% of the decommissioning waste cannot be disposed of in a land disposal repository. It is expected that the source terms and waste classification evaluated through this study can be widely used to establish a decommissioning/disposal strategy and fuel cycle analysis for CANDU reactors.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.799-811
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• 2006

As an alternative measure to replace reactive stance with proactive one, a risk based management scheme has been commonly applied to enhance public satisfaction on water service by providing a higher creditable solution to handle a rehabilitation problem of pipe having high potential risk of leaks. This study intended to examine the feasibility of a simulation model to predict a recurrence probability of pipe leaks. As a branch of the data mining technique, probabilistic neural network (PNN) algorithm was applied to infer the extent of leaking recurrence probability of water network. PNN model could classify the leaking level of each unit segment of the pipe network. Pipe material, diameter, C value, road width, pressure, installation age as input variable and 5 classes by pipe leaking probability as output variable were built in PNN model. The study results indicated that it is important to pay higher attention to the pipe segment with the leak record. By increase the hydraulic pipe pressure to meet the required water demand from each node, simulation results indicated that about 6.9% of total number of pipe would additionally be classified into higher class of recurrence risk than present as the reference year. Consequently, it was convinced that the application of PNN model incorporated with a data base management system of pipe network to manage municipal water distribution network could make a promise to enhance the management efficiency by providing the essential knowledge for decision making rehabilitation of network.

• Education of Primary School Mathematics
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• v.19 no.1
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• pp.79-112
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• 2016

The purpose of this research is to find the effects of learner-centered instruction based on constructivism (LCIC) on their knowledge generation level and reasoning ability. To look for them, after fraction units are re-planed for implementing LCIC, instructions using it provide students in a class. From the data, some conclusions can be drawn as follows: LCIC has more positive influence of students on recall ability, generation ability, and reasoning ability than tractional instruction method. With the data it can be said that the interaction exists between learners' reasoning ability and generation level.

• Education of Primary School Mathematics
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• v.21 no.4
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• pp.415-430
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• 2018

The purpose of this study was to get reflections on teaching numbers and operations for special education from analyzing lessons for counting, addition and subtraction of natural number with counting board for students with autism. In order to attain these purposes, this study analyzed the lessons for counting, addition and subtraction of natural number to students with autism in 4th and 6th graders in special class at regular elementary school using counting board for one hour per week for 30 weeks. According to the analysis, counting board that reveals the structure of numbers becomes an effective mathematical materials, and using the counting strategy and computation strategy can be an effective method of teaching, and it is possible to teach mathematical communication to students with autism. From this result, this study presented suggestions for teaching counting, addition and subtraction for students with disabilities.

• Journal of the korean society of oceanography
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• v.32 no.4
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• pp.163-170
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• 1997

Some CMP gathers acquired from shallow marine seismic reflection survey in offshore Korea do not show the hyperbolic trend of moveout. It originated from so-called swell effect of source and streamer, which are towed under rough sea surface during the data acquisition. The observed time deviations of NMO-corrected traces can be entirely ascribed to the swell effect. To correct these time deviations, a residual statics is introduced using Genetic Algorithms (GA) into the swell correction. A new class of global optimization methods known as GA has recently been developed in the field of Artificial Intelligence and has a resemblance with the genetic evolution of biological systems. The basic idea in using GA as an optimization method is to represent a population of possible solutions or models in a chromosome-type encoding and manipulate these encoded models through simulated reproduction, crossover and mutation. GA parameters used in this paper are as follows: population size Q=40, probability of multiple-point crossover P$_c$=0.6, linear relationship of mutation probability P$_m$ from 0.002 to 0.004, and gray code representation are adopted. The number of the model participating in tournament selection (nt) is 3, and the number of expected copies desired for the best population member in the scaling of fitness is 1.5. With above parameters, an optimization run was iterated for 101 generations. The combination of above parameters are found to be optimal for the convergence of the algorithm. The resulting reflection events in every NMO-corrected CMP gather show good alignment and enhanced quality stack section.

• Journal of Animal Environmental Science
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• v.16 no.1
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• pp.29-40
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• 2010

The purpose of the study is to review current studies for economic values on livestock products produced by animal welfare. In order to review the topic, published research papers and reports were reviewed in the world. As the result of the study, the studies for the topic are not researched actively. The main ideas for the studies were consumer survey on meats and egg. Data were questionnaire, Lexis-Nexis databases, consumptions and prices on meats, auction data. Tools for analyses were Random parameters logit and latent class model, WTP analysis, Roterdam model, Pearson's Chi test, Mann-Whitney V-test, Kruskal-Wallis test, structural equation model, regression model, Target-costing, and conjoint analysis.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.489-504
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• 1996

The purpose of this study was to compare the adaptation to the tooth structure of five light cured glass ionomer cements (Fuji II LC. VariGlass VLC, Vitremer, Dyract and Geristore). Human, non-carious fifty extracted permanent premolars stored in normal saline were used. Class V cavity preparations were created on the buccal surfaces. The occlusal margin of each cavity was placed on the enamel and the gingival margin was placed on the cementum/dentin. The teeth were then distributed at random into five groups of 10 teeth each. Group 1: Fuji II LC, Group 2 : VariGlass VLC, Group 3 : Vitremer, Group 4: Dyract, Group 5 : Geristore. The prepared cavities were restored with one of the five light cured glass ionomer cements. The manipulation of each material was handled according to the manufacturer's instructions. All samples were placed in incubator of 100% relative humidity at $37^{\circ}C$ for 24 hours. The roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned buccolingually through the center of restorations. The cut interfaces were gradually hand polished on sandpapers from 300 up to 1200 grit. The adaptation at the tooth/cements interface was assessed by SEM (JSM-840A, JEOL Ltd.). The results of this study were as follows : 1. Group 2 revealed the best adaptation and groups 1, 4 and 5 revealed similar adaptation pattern to the cavity walls. Group 3 revealed the worst adaptation to the cavity walls. 2. Enamel margins showed better adaptation than dentin/cementum margins with each material except group 3. 3. The hybrid layers were observed between the glass ionomer cement and dentin in groups 2, 4 and 5.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1243-1248
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• 2008

As development in technology of bioinformatics recently mates it possible to operate micro-level experiments, we can observe the expression pattern of total genome through on chip and analyze the interactions of thousands of genes at the same time. In this thesis, we used CDNA microarrays of 3840 genes obtained from neuronal differentiation experiment of cortical stem cells on white mouse with cancer. It analyzed and compared performance of each of the experiment result using existing DT, NB, SVM and multi-perceptron neural network classifier combined the similar scale combination method after constructing class classification model by extracting significant gene list with a similar scale combination method proposed in this paper through normalization. Result classifying in Multi-Perceptron neural network classifier for selected 200 genes using combination of PC(Pearson correlation coefficient) and ED(Euclidean distance coefficient) represented the accuracy of 98.84%, which show that it improve classification performance than case to experiment using other classifier.

• The Mathematical Education
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• v.58 no.1
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• pp.121-138
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• 2019

The purpose of this study was to analyze the trends of domestic research on mathematics teacher education in terms of the period, topics, methods, subjects, and mathematics content strands. For this purpose, a total of 220 research articles dealing with mathematics teacher education were analyzed, which have been published since 2000 by the Korean Society of Mathematics Education in the three journals: (a) The Mathematical Education; (b) Education of Primary School Mathematics; and (c) Communications of Mathematical Education. Regarding the period when the research was conducted, the number of articles on mathematics teacher education has been rapidly increased since the late 2000s. Regarding the topics, research on teacher orientation has been the most frequent topic and the studies dealing with professional development for teachers, teaching practices, or teacher knowledge tend to be popular. Regarding methods, survey and case study have been most frequently employed in studying mathematics teacher education. Regarding subjects, the main participants were in-service teachers, pre-service teachers, elementary school teachers, and secondary school teachers, respectively, who were in charge of a regular class. Finally, regarding mathematics content strands, previous studies on mathematics teacher education were not specific to mathematics content strands. Given these results, this paper closes with important implications for future research directions on mathematics teacher education in Korea.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.12
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• pp.137-148
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• 2019

Korean piloti-type buildings are comprised of pilotis in the first story and shear walls in the upper stories. This vertical irregularity causes excessive lateral plastic deformation on the first story while the upper stories stay elastic. Meanwhile, asymmetric position of structural components such as core walls and columns of RC piloti-type buildings tends to produce torsional irregularities of the structures. Korean Building Code(KBC2016) requires the special seismic load and torsional amplification factor to apply to the piloti-type buildings lower than six-story or 20m if it has vertical and torsional irregularities when the building corresponds to seismic design category C or D. Many Korean low-rised RC buildings fall into the class. Therefore, the special earthquake load and torsional amplification factor are often applied to a building simultaneously. However, it has not been studied enough how much influence each parameter has on buildings with vertical and torsional irregularities at the same time. The purpose of this study is to evaluate the effect of factor special seismic load and torsional amplification on seismic performance of irregular buildings. In this study, a damaged 4^th story piloti-type building by the Pohang earthquake was selected and the earthquake response analysis was carried out with various seismic design methods by the KBC 2016. The effect of the design parameters on seismic performance was analyzed by the dynamic analysis of models with special seismic load and torsional amplification factor based on the selected building. It was concluded that the application of the torsional amplification factor to the reference model to which special seismic design was applied, does not significantly affect the seismic performance.