• Journal of The Korean Association For Science Education
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• v.19 no.4
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• pp.684-695
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• 1999

In this study, the 'extended science investigation' was conceptualized as a comprehensive science investigation contrasted with exercise of process and skill component and cookbook style experiment. The extended investigation tasks can be characterized with practical context. openness and continuity. The purpose of this study is to describe the change of students' cognitive engagement while they perform the extended science investigations and to explore how the characteristics of the extended investigation tasks affect the students' cognitive engagement. 128 7th graders attending coeducational school in Seoul were participated in this study. The questionnaire was implemented repeatedly to monitor students' cognitive engagement. And ten students were interviewed to explore the cause of the change of cognitive engagement. The result showed that there was no difference between directive traditional investigations in textbook and developed extended investigations in understanding of the content and whole process of investigations but participants' commitment was increased significantly in the extended science investigations. Especially the extent of students' understanding and commitment became higher in the second half than in the first half of the extended science investigations. The openness of the extended investigation tasks contributed on the increase of commitment. And the continuity of the tasks contributed on the increase of students' understanding in the second half of the extended science investigations.

• Journal of The Korean Association For Science Education
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• v.21 no.1
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• pp.1-12
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• 2001

The extended science investigations, comprehensive investigations contrasted with exercises of process skill components and cookbook style experiments, should be pursued for giving opportunity of more authentic science activity. The characteristics of the extended investigation tasks were emerged from critical argument on school practical work. And one of important educational objectives in students' investigations is to achieve motivation for investigation. The purpose of this study is to explore how the characteristics of the extended investigation tasks, that is practical context, openness and continuity, affect middle school students' motivation for investigation. On the basis of questionnaire results and students' school science achievement, ten students were interviewed to see the change of motivation for investigation and its causes while they perform two textbook investigations and four extended investigation tasks. Among the interviewees, the students who showed positive motivation for the extended investigations were critical about textbook experiments as they are just confirmations of theories and perceived practical context and openness as the main causes of their positive motivation. The students who showed negative motivation for extended investigations preferred textbook experiments as there was enough guidance from teacher and textbook-centered learning. They recognized the openness of the tasks as a main reason of their negative motivation for investigation. Some students showed negative responses about continuity of the extended investigation tasks but continuity was not recognized as a main cause for their motivation for investigation.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.137-153
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• 2000

In this study. 'extended science investigation' was conceptualized as a comprehensive science investigation contrasted with exercise of process and skill component and cookbook style experiment. The extended investigations should be pursued for giving opportunity of more authentic science activities in school science. And one of important educational objectives in students' science investigations is to achieve motivation for investigation which drives and triggers further investigations. It can be discerned as positive and negative by its direction and also as internal and external by its cause. The purpose of this study was to describe change of students' motivation for investigation while they were performing the extended science investigations. The subject was 128 7th grader attending coeducational school in Seoul. Questionnaires and students' reports were analysed complementarily to describe students' motivation for investigation. The number of students who showed positive motivation for investigation did not increase in the developed extended investigations than in the directive investigations in textbook, but the cause of positive motivation for investigation has changed largely from task-exclusive factors to task-inclusive factors. In case of negative motivation for investigation, regardless of the kind of investigation task, task-inclusive factors were recognized as the main causes. Among those whose motivation changed during successive extended investigations, the students who showed change from negative to positive were more than the reverse. And the number of positive intrinsic motivation for investigation was increased at the second half of the extended science investigations. So it can be said that there was a desirable change of motivation for investigation at the second half the extended science investigations.

• Journal of The Korean Association For Science Education
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• v.32 no.9
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• pp.1470-1488
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• 2012

This study examined changes in the quality of written arguments produced by freshman students in general chemistry laboratory classes using the SWH approach over a semester; difference in the quality of written argument between the original writing template (year I) and the extended writing template (year II); and any difference between Total Argument and Holistic Argument scores. 140 writing samples from 14 students on the year I and 228 samples from 19 students on the year II were collected. Results indicated that despite fluctuations, the students were producing stronger argument by the end of semester compared to the beginning of the semester. Original SWH template group received significantly higher argument scores than extended SWH template group. For the most of year I laboratory investigations, there was no significant difference in the quality of argument between Total Argument and Holistic Argument scores. An implication of this study would be to provide opportunities for students to practice constructing arguments using the original SWH writing template including questions, claims, evidence, and reflection.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.4
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• pp.421-428
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• 2000

Accelerator Mass Spectrometry (AMS) is presented for the applications to the environmental research. Traditionally the radiocarbon (14C) measurements have been made for the purpose of dating the archaeological and geological samples. 14C measurements using AMS however have become the more useful methods for the study of environmental science such as antropogenic modification of atmosphere and the determination of mixing ratios of fossil and biomass products. Such 14C AMS measurements have been extended to the discovery of new chemical tracers for investigations of sources of excessive contributions of CO2, CO, CH4 and other carbon-bearing molecules in the atmosphere.

• Journal of the Korean earth science society
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• v.24 no.2
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• pp.93-99
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• 2003

The purpose of this study was to develop a new test instrument based on AAAS Benchmarks for Science Literacy, to assess k-12 students' progress in understanding nature of science (NOS). A total of 276 items were developed including 33 items for grade k-2, 36 items for grade 3-5, 78 items for grade 6-8 and 129 items for grade 9-12 and they were reviewed for validity and reliability. Key ideas that were the foundation of test items were extended, sophisticated and enriched according to the grade level. The general score of this test represents a student's cognitive state about an understanding of NOS. The result of this test can be expected to give some useful information for follow-up investigations, improving instructional design, and conducting further studies.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.803-806
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• 2003

This paper presents a detailed study of the extended Kalman filter for estimating the rotor speed of an IM drive. The general structure of the Kalman filter is reviewed and the various system vectors and matrices are defined. By including the rotor speed as a state variable, the EKF equations are established from a discrete two axis model of the three-phase induction motor using the software MATLAB/Simulink, simulation of the EKF speed estimation algorithm is carried out for an induction motor drive with direct self control. The investigations show that the EKF is capable of tracking the actual rotor speed provided that the elements of the covariance matrices are properly selected.

• Food Science and Industry
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• v.49 no.2
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• pp.56-62
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• 2016

Although the production of chestnut in Korea is the second largest in the world, domestic consumption of chestnut is very limited. Furthermore, consumption of chestnut in Korea is highly dependent on export to Japan and China. Large amount of chestnut in Korea have been deteriorated and discarded during storage. In order to increase the consumption of chestnut in Korea, it is necessary to know the processing properties of chestnut and its starch. Additionally, through the various investigations such as modification treatment, it will be extended to utilization of chestnut. So far, there is a little information on the processing properties of chestnut; therefore, the expansion of research will bring results to increase the consumption of chestnut.

• Biomedical Science Letters
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• v.12 no.3
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• pp.267-274
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• 2006

Klebsiella pneumoniae is the leading cause of nasocomial infection and the most commonly isolated from clinical specimens. $Extended-spectrum-{\beta}-lactamase$ (ESBL) producing K. pneumoniae infection was associated with a significantly longer duration of hospital stay and greater hospital charges. The purpose of this study is to investigate the antibiotic resistant patterns and the DNA fingerprint types of extended-spectrum ${\beta}-lactamase$ (ESBL) producing K. pneumoniae. 223K. pneumoniae strains were collected from three general hospitals with more than 500 beds in Busan, Korea from September 2004 to October 2005. The minimum inhibitory concentration (MIC) of antibiotics was measured using the Gram negative susceptibility (GNS) cards of VITEK (Vitek system, Hazelwood Inc., MO). Random amplified polymorphic DNA method was used to detect DNA fingerprint of the organisms. Of the 226 K. pneumoniae isolates 65 ESBL-producing K. pneumoniae strains were detected by the Vitek system and confirmed by the double-disk synergy test. All the 65K. pneumoniae strains were resistant cefazolin, cefepime, ceftriaxone and aztreonam, and 83.0% of the organisms were resistant to ampicillin/sulbactam, 66.1% to tobramycin, 67.6% to piperacillin/tazobactam, 61.5% to ciprofloxacin, and 47.6% to trimethoprim/sulfamethoxazole and 43.0% to gentamicin. The RAPD patterns were distincted as 10 types by three random 10-mer primers (208, 272, 277). Among ten type patterns, three types (Ic, IIb, IIIe) were remarkably represented at patient of internal department, nerve surgery department, general surgery department, and neonatal room. These results indicate that RAPD can be useful for DNA of strains typing in the epidemiological investigations. Therefore more investigation are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosphorin antibiotics.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.645-651
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• 2019

Spiradiclis hainanensis H.S. Lo and S. purpureocaerulea H.S. Lo (Rubiaceae) are reported as new additions to the flora of Vietnam. In Vietnam, the genus Spiradiclis has been represented by only two species, S. leptobotrya (Drake) Pit. and S. caespitosa Blume. During our field investigations in the Lao Cai and Ninh Binh Provinces of northern Vietnam, we collected two interesting specimens of Spiradiclis that were earlier known only from China and unknown in Vietnam. Here, we report S. hainanensis and S. purpureocaerulea as previously unrecorded species from Vietnam. Detailed descriptions and color photographs are provided along with a taxonomic key for Spiradiclis species in Vietnam.