• Research in Mathematical Education
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• v.18 no.1
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• pp.75-87
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• 2014

It is central to use a scale to measure a person's level of a construct in mathematics education research. This article explains a practical process through which a researcher rapidly can develop an instrument to measure the construct. The process includes research questioning, reviewing the literature, framing a background theory, treating the data, and reviewing the instrument. The statistical treatment of data includes normality analysis, item-total correlation analysis, reliability analysis, and factor analysis. A virtual example is given for better understanding of the process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.79-83
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• 2018

An accurate method to measure shielding effectiveness(SE) of EMI spray coating film is presented. After high frequency simulating, Circular coaxial standard test fixture is fabricated. A sample of EMI spray coating film was fabricated for insertion into a circular coaxial standard test fixture. The measuring instrument used an Agilent 8722ES vector network analyzer for the SE measurement. The exact SE of copper and silver mixed spray coating sample was measured by the composition of the measuring instrument and the measuring sample. The SE of copper sample was measured at 70 dB and the SE of copper and silver mixed spray coating sample was measured at 60 dB. As a result of the measurement, the reliability of the circular coaxial standard test fixture was confirmed.

• Particle and aerosol research
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• v.10 no.4
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• pp.163-167
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• 2014

Particle number portable emission measurement system (PN-PEMS) is an instrument for measuring number concentration of automobile exhaust. The principle of some pre-existing commercial PN-PEMS is to charge particles and display the number of particles by measuring current. However, this method has some problems for measuring exhaust. In this study, to solve these issues, we have developed a single particle counting PN-PEMS based condensation particle counter (CPC). The PN-PEMS based CPC does not affect driving conditions and it is convenient for mobile because the instrument is small and light in structure. We evaluated counting efficiency of PN-PEMS based CPC by using electrostatic method (electrometer and Faraday cup).

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.161-163
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• 1997

Heatcycle testing for aluminum connector is very important. But because of connecting or disconnecting the test circuit, measuring resistance is difficult. Also the previous measuring resistance instrument is analog type. So measuring method is difficult. And four measuring points for one test circuit cause difficulty in automation. In this paper we developed the automatic system for measuring resistance. Automation will allow more information to be gathered, which will lead to the connector aging process being better understood and controlled.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.3
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• pp.276-291
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• 2016

This study is to develop a valid and reliable instrument for measuring students' creative engineering problem solving propensity. The creative engineering problem solving is operationally defined in this study as a creative problem solving skill in an engineering context. To develop the instrument, first we define seven common constructs between engineering problem solving skill and creative problem solving skill through an intensive literature review; motivation, context, personal character, engineering design, engienering habits of mind, understandings of engineering and engineers, communication skill, and collaboration skill. Based on the seven constructs and the face validity test conducted by two in-service science teachers and 4 experts in science education research, 40 preliminary items were developed. Then the preliminary instrument was implemented in a science gifted highschool to measure the reliability of the instrument. From the 40 items, 34 items were selected through the initial reliability test by Cronbach's ${\alpha}$(>.75). Finally through the three times of factor analysis process, 28 items in five construct categories were selected; motivation (3 items), engineering design (6 items), engineering habits of mind (9 items), understandings of engineering and engineers (4 items), communication and collaboration skill (6 items). The factor analysis result showed that the reliability of each construct category was between .733 to .892., meaning that the instrument is reliable in terms of the higher structural validity (each item is categorized in an appropriate construct category). We expect that the creative engineering problem solving propensity instrument developed in this study can be used in various contexts for STEAM education research as a reliable and valid instrument.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1109-1118
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• 2013

Recently, stereoscopic three-dimensional(S3D) movie and video are becoming globally popular. However, there are some people who could not perceive 3D depth information well. Traditional stereopsia test tools could not analyze the subject's perceived depth accurately. Therefore, it is necessary to have a test tool that accurately measures the degree of perceived depth of subjects. In this paper, we suggested a 3D content depth measuring instrument and produced suitable 3D contents for the instrument. We measured subjects' perceived depth of 3D foreground objects in terms of $+1^{\circ}$, $-1^{\circ}$, $-2^{\circ}$ binocular disparity and compared the measured values with the theoretical values. Measured values were slightly bigger than the theoretical values. Deviation between the measured values and theoretical values increased with extrusion distances.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.518-518
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• 2008

We propose an optical-based measuring instrument of catenary system in electric railway. This system was made to utilize line scan camera as inspecting system to measure the stagger and height of overhead contact wire in railway and composed with optical type source and FPGA-based image acquisition system with PCI slot. Vision acquisition software has been used for the application to programming interface for image acquisition, display, and storage with a frequency of sampling. The proposed optical-based measuring instrument to measure the contact wire geometry shows promising on-field applications for online condition motoring. Also, this system can be applied to measure the hight and stagger or other geometry of different type of overhead catenary system.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.48-58
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• 2022

This study tried to assess the applicability of a hand-held LiDAR for measuring the geometric structures of forest trees including diameters at a breast height(DBH) and tree height(H). A traditional method using tapelines was conducted to analyze the accuracy of the LiDAR instrument in the Taebaeksan national park in South Korea. Four statistical indices which are bias, root mean square error, mean absolute error, and correlation coefficient were employed to compare the measurements by the LiDAR instrument and traditional method. The DBHs from the LiDAR were very similar to those from the traditional method. And it indicated that the LiDAR is sufficient to be a alternative of a traditional method. However, there was a limitation in assessing the accuracy of LiDAR for measuring tree height by comparing the measurements by observer's eyes since they included different error sources. Further study is needed to assess the accuracy of LiDAR instrument for tree height through more reliable measurements.

• Journal of The Korean Association For Science Education
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• v.13 no.1
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• pp.80-91
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• 1993

The purpose of this study is to develop an reliable instrument for evaluating science inquiry skills through an R&D procedure. A total of ten seience inquiry skills were selected for the development of the instrument, ie, observation, classifying, recognizing problems, measuring, inferring, formulating hypothesis, controlling variables, experimenting, interpreting and drowing a conclusion. And three items were developed for each sceince inquiry skill, totaling up to thirty items. The content areas of developed items are divided into three categories, material and energy, life and environment, and the earth and the space. There are 10 items for each category. The content validity and the objectivity of developed items were checked, verified in the two field trials and revised according to the analysis of items by seven experienced specialists with the degree of doctors in science education and five teachers who were studying for their master's degree in science education. According to the results of the second field trial. the content validity of the instrument was 91.1%, reliablity(K-R 20) 0.78, defficulty index 49.13%, discrimination index 0.42, mean achivement 61.85%, standard deviation 5.11, and standard error 2.40. Considering the above results, the developed instrument in this study is regarded as a appropriate instrument for evaluating science inquiry skills of elementary school students.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.216-217
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• 2019

The battery powered electric vehicle (EV) is one of most promising technologies in 21^st century. Though the lithium batteries are playing an important role in the EVs, they are only applicable until their capacities reach 80%, the end of its useful first life. Yet, these batteries can live a second life such as Energy Storage Systems (ESS). In order to utilize the Residual Useful Life (RUL) of the batteries the State of Health (SOH) of them needs to be estimated by a nondestructive test such as Electrochemical Impedance Spectroscopy (EIS) technique. Though many kinds of different EIS instruments are commercially available, most of them can only test a battery module less than 10V and the price of the instrument is very high. In this paper a low-cost EIS instrument suitable for measuring the impedance spectrum of the high voltage battery module is proposed and its validity is verified through the experiments. In order to prove the accuracy of the developed EIS instrument its measured impedance spectrum is compared with the results obtained by a commercial instrument. The Chi Square value calculated between two impedance spectrum measured by both developed and commercial instruments are less than 2%, which prove the strong correlation between two results.