• Kyungpook Mathematical Journal
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• v.47 no.1
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• pp.77-79
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• 2007

In this note we point out how a theorem of Gamelin and Garnett from function theory can be used to establish a spectral mapping theorem for an arbitrary contraction and an associated class of $H^{\infty}$-functions.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.248-256
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• 2010

This study investigated the effects of the level of enrichment for analogies upon students' mapping, conceptual understanding, and the types of mapping errors in concept learning about Boyle's Law. Analogical reasoning ability test was administered and the score was used as a blocking variable. Three types (simple, enriched, and extended analogies) of learning materials according to the level of enrichment for analogies were studied by randomly assigned middle school students, and a conceptions test and a mapping test were administered immediately. The retention tests of both were administered four weeks later. Analyses of the results revealed that there was no main effect in the level of enrichment for analogies, but there was interaction effect with analogical reasoning ability in the post test on mapping. And the score of enriched analogy group was significantly higher than those of simple analogy group, but the score differences among three groups were not significant in the retention test on conceptual understanding. The frequency of the total mapping errors in the simple analogy group was the highest, and the frequencies of most types of mapping errors in the enriched and the extended analogy groups were less than those in the simple analogy group. There were also some differences in the frequencies of mapping errors with respect to the level of analogical reasoning ability. Therefore, these results will help science teachers plan and practice instructions using analogy.

• Journal of The Korean Association For Science Education
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• v.23 no.6
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• pp.617-626
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• 2003

Although many studies have investigated the effectiveness of concept mapping and the learning cycle, in Korea none have explored the effectiveness of concept mapping and the learning cycle combined. This study explored the effectiveness of concept mapping, the learning cycle, and a combination of concept mapping/learning cycle(CL) in high school biology class. Students' science achievement, the science related attitudes and scientific inquiry ability was measured. The results indicated that concept mapping, the learning cycle, and CL treatment were significantly different from the traditional one in science achievement(p< .05). However, the three treatments were not significantly different from each other. No significant difference exists among different learnings in high and average-ability students. But, concept mapping was the most effective in low-ability students. For the students' scientific inquiry ability, CL and learning cycle were more effective than concept mapping and traditional learning. No significant difference exists among different learnings in high-ability students. CL and learning cycle were more effective than concept mapping and traditional learning in average and low-ability students. For the students' science related attitudes, concept mapping, the learning cycle, and CL were more effective than the traditional learning. But, there was no significant difference among these three groups.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.402-414
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• 2012

This study investigated the effects of the instructions using analogies in learning the concept of saturated solution by the analogy presentation types and the verbal learning styles upon the mapping understanding, the mapping errors, and the perceptions of the instruction. Fifth graders (N=123) at an elementary school were selected and assigned to VA (n=63) and VPA (n=60) groups. As a pretest, a test on the verbal learning style was administered. The students in the VA group learned the target concept with a verbal analogy, while those in the VPA group learned it with a verbal/pictorial analogy. After the students learned it, a mapping understanding test was administered. The students in the VPA group also administered the test on the perceptions of the instruction and some of them were interviewed in depth. The results revealed that the scores of the students with strong verbal learning preference in the VPA group were significantly lower than those in the VA group in the mapping understanding test. However, the scores of the students with weak verbal learning preference were not significantly different between the two groups. Five types of mapping errors were identified: failure to map, mismapping, rash mapping, impossible mapping, and mapping of a surficial feature. According to students' verbal learning styles, there were some differences in the frequencies of mapping errors in the two groups. Many students in the VPA group, regardless of their verbal learning styles, had positive perceptions of the instruction in various cognitive and motivational aspects. However, some of them also pointed out a few difficulties of the instruction. Educational implications of these findings are discussed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.11
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• pp.11-18
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• 2007

FFT(Fast Fourier Transform) processor is one of the key components in the implementation of OFDM systems such as WiBro, DAB and UWB systems. Most of the researches on the implementation of FFT processors have focused on reducing the complexities of multipliers, memory and control circuits. In this paper, to reduce the memory size required for IFFT(Inverse Fast Fourier Transform), we propose a new IFFT design method based on a mapping method. By simulations, it is shown that the reposed IFFT design method achieves more than 60% area reduction and much SQNR(Signal-to-Quantization-Noise Ratio) gain compared with previous IFFT circuits.

• Korean Journal of Computational Design and Engineering
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• v.19 no.2
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• pp.182-190
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• 2014

Parametric modeling is one of BIM's characteristics and BIM have being utilized for constructability analysis, energy efficiency analysis, and so on in diverse construction field. However, parametric information's interoperation is not solved until now because different BIM tools have specific algorithm and methods to generate geometric information. To solve the problem, previous research suggested IFC-XML methodology. In this paper, authors studied connections between IFC-XML structure and script-based modeling commends to make libraries in commercial BIM tools such as ArchiCAD$^{TM}$ and Digital Project$^{TM}$. In addition, they made commends mapping tables to exchange geometry information of architectural components. Moreover, mapping system was developed to certify the mapping tables which is classified modeling commends. Finally, translated architectural component model was confirmed using exchanged geometry information in browser.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.73.1-73.1
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• 2017

Reverberation mapping is one of the best way to investigate structure and kinematics of broad-line regions around central supermassive black holes of active galactic nuclei (AGN). It is usually used to estimate masses of supermassive black holes. So far, reverberation mapping studies have achieved good results for dozens of AGN by spectroscopic monitoring. However, spectroscopic monitoring is time consuming and high cost. Here, we present result of photometric reverberation mapping with medium-band observation. We monitored five nearby AGN which are already studied, have short time-lag, and show bright H-alpha emission lines. Observation has been performed for ~3 months with ~3 days cadence using three medium-band filters installed in LSGT (Lee Sang Gak Telescope). We found 0.01-0.06 magnitude variations by differential photometry. Also time-lags between continuum light-curves and H-alpha emission line light-curves are calculated using Javelin software. The result shows that our study and previous studies are consistent within uncertainty range. From verification of availability in this study, photometric reverberation mapping could be used as a powerful tool to measure central supermassive black holes for large samples and high-redshift AGN in the future.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.125-138
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• 2017

Reliability-based design optimization (RBDO) is a powerful tool for design optimization when considering probabilistic characteristics of design variables. However, it is often computationally intensive because of the coupling of reliability analysis and cost minimization. In this study, the concept of reliability mapping function is defined based on the relationship between the reliability index obtained by using the mean value first order reliability method and the failure probability obtained by using an improved response surface method. Double-loop involved in the classical RBDO can be converted into single-loop by using the reliability mapping function. Since the computational effort of the mean value first order reliability method is minimal, RBDO by using reliability mapping functions should be highly efficient. Engineering examples are given to demonstrate the efficiency and accuracy of the proposed method. Numerical results indicated that the proposed method has the similar accuracy as Monte Carlo simulation, and it can obviously reduce the computational effort.

• International Journal of Knowledge Content Development & Technology
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• v.2 no.1
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• pp.51-65
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• 2012

While science and technology information service portals and heterogeneous databases produced in Korea and other countries are integrated, methods of connecting the unique classification systems applied to each database have been studied. Results of technologists' research, such as, journal articles, patent specifications, and research reports, are organically related to each other. In this case, if the most basic and meaningful classification systems are not connected, it is difficult to achieve interoperability of the information and thus not easy to implement meaningful science technology information services through information convergence. This study aims to address the aforementioned issue by analyzing mapping systems between classification systems in order to design a structure to connect a variety of classification systems used in the academic information database of the Korea Institute of Science and Technology Information, which provides science and technology information portal service. This study also aims to design a mapping system for the classification systems to be applied to actual science and technology information services and information management systems.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.4
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• pp.213-220
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• 2017

This study examines the limitations of existing crime mapping that relies mainly on reported crime data, suggests a crime mapping method based on experts' and users' assessments of a neighborhood environment as an alternative approach, and conducts a case study on a real-world site by applying the suggested approach. According to the results of the case analysis, while the areas adjoining arterial roads with heavy pedestrian traffic were shown as high crime risk areas in the crime map based on actual reported crime data, the areas adjoining local roads with low pedestrian traffic were high-risk areas in the crime risk area map based on experts' and residents' evaluations. This study makes a contribution to the field in that it demonstrates the detailed application process of crime risk area mapping according experts' and residents' evaluations, compares the results with those of an existing crime map, and finally shows that the former can function as a complement to the latter.