• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.2
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• pp.98-103
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• 2009

An RF test structure is proposed and its applicability is confirmed by measuring DC characteristics and high frequency characteristics. Effective mobility extraction is also performed to confirm the validity of proposed test structure. The area of suggested test structure consumed on wafer was decreased by more than 50% and its characteristics do not be degraded compared with conventional structure.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.433-439
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• 2018

This study considers the design of a submodule test circuit for the modular multi-level converter (MMC)-based HVDC systems. A novel submodule test circuit is proposed to provide not only an AC but also a DC component to the submodule current. However, the current waveforms depend on the capacitor voltages. Therefore, determining the capacitance value of the test circuit is important. Finding a proper capacitance value is easy when the proposed analysis method is used. Simulation and experimental results show the usefulness of the proposed method.

• Architectural research
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• v.20 no.4
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• pp.129-135
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• 2018

In order to compare the development performance of headed reinforcing bar and straight reinforcing bar in tension for steel fiber reinforced concrete (SFRC), pullout test of specimens with reinforcing bar which was anchored on simple beam perpendicularly was conducted. The experimental variables were steel fiber volume ratio ($V_{Rsf}$), concrete compressive strength, and existence of head. As the result of test, splitting failure of concrete in the development direction of reinforcing bar in most specimens was observed. For development detail of headed reinforcing deformation bar, specimens with 1% $V_{Rsf}$ showed approximately 63%~119% increase in pullout strength compare to specimens with 0% $V_{Rsf}$. Test result shows that SFRC is more effective in increasing pullout strength for headed reinforcing bars than increasing pullout strength of straight bars.

• Smart Structures and Systems
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• v.31 no.6
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• pp.601-619
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• 2023

In this study, the accuracy of a real-time hybrid test (RTHT) employed for a performance test of a tuned mass damper (TMD) on an offshore wind turbine (OWT) with a complicated jacket-type supporting structure is quantified and evaluated by comparing the RTHT results with the experimental data obtained from a shaking table test (STT), in which a 1/25-scale model for a typical 5-MW OWT controlled by a TMD was tested. In the RTHT, the jacket-type OWT structure was modelled using both multiple-DOF (MDOF) and single-DOF (SDOF) numerical models. When compared with the STT test data, the test results of the RTHT show that while the SDOF model, which requires less control computational time, is able to well predict the peak responses of the nacelle and TMD only, the MDOF model is able to effectively predict both the peak and over-all time-history responses at multiple critical locations of an OWT structure. This also indicates that, depending on the type of structural responses considered, an RTHT with either an SDOF or a MDOF model may be a promising alternative to the STT to assess the effectiveness of a TMD for seismic mitigation in an OWT context.

• Journal of Navigation and Port Research
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• v.38 no.1
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• pp.11-18
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• 2014

To confirm whether the square tank at Changwon National University (CWNU) can be used for estimation of maneuverability, planar motion mechanism (PMM) test and circular motion (CM) test were performed for various conditions. PMM test can be implemented using an XY carriage and a yaw table in the square tank. However, sometimes test section is insufficient for PMM test owing to low length-breadth ratio of the tank. In addition, the speed of a towing carriage is also quite limited. Therefore, it would be useful if PMM test could be effectively performed diagonally, by establishing coupled control logic to drive three servomotors. In addition, Froude number dependency on the estimated hydrodynamic coefficients was checked. Furthermore, CM tests, which cannot be completed in a conventional linear towing tank, were performed, and its results were compared with the results of PMM test. The results of the PMM tests in the diagonal direction were consistent with the results of the test performed in the direction parallel to the sidewall. However, the results of the CM test were greater than those of the PMM test. This tendency was also observed in the results published at Ulsan University.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.77-83
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• 2008

Semi-active cabin air suspension system improves driver's comfort by controlling the damping characteristics in accordance with driving situation. For the driver's comfort evaluation, test procedure has the two methodologies which are filed test and lab test. A field test method has a drawback. It requires a lot of time and money on repetitive test, due to the sensitivity of field test. On the other hand, the test with six axes simulation table at laboratory can obtain the repeatability of test, better than the field test method. In this paper, the procedures of ride performance test and control logic tuning with the table are presented. Drive files of the table can be represented with the almost same input condition as field test data. According to the result from the comparative test using six axes simulation table between passive and semi-active system by making ECU logic tuning, the RMS acceleration of semi-active cabin air suspension system was reduced by 29.6% compared with passive system.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.452-458
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• 2019

This study proposes a new test circuit and control method for the submodules of modular multilevel converter (MMC)-based HVDC systems. The test current of conventional submodule test circuits cannot provide the DC offset components or may have some distortion in the linearized current with the DC offset. The proposed scheme can provide not only the DC component but also linearized current without distortion. Therefore, the submodule test current waveform is relatively similar to that of a real submodule consisting of an MMC-based HVDC system. The validity of the proposed circuit and control method is verified through a simulation and experiment.

• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.49-54
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• 2015

Acute toxicity test with Daphnia magna has a variety of factors such as incubation condition of test species, food quality and proficiency of laboratory workers. Therefore, proper proficiency testing samples were required for evaluating the competence of laboratory workers. This study aims to propose some appropriate proficiency testing samples for laboratory workers of acute toxicity test with Daphnia magna. Proposed four kinds of standard samples (Sample A, B, C, and D) for proficiency testing were selected from reference materials which were recommended from Canada and USA WET(Whole Effluent Toxicity) authorities. Proposed standard samples were tested by trial application of proficiency testing, homogeneity and stability checks using repeatability test. Sample A, C and D were estimated ad the suitable candidates for proficiency test standard samples except for Sample B. In addition, Sample A was proved to be the most suitable sample.

• Architectural research
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• v.20 no.4
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• pp.137-145
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• 2018

The nondestructive test is widely used in the field of diagnosis and maintenance to evaluate the degree of damaging of structures caused by aging, and the demand for this test method is expected to continue increasing. However, there is a lack of standards related to the nondestructive test, and South Korea is relying heavily on developed nations for original technologies related to diagnosis. It is an urgent task to establish a nondestructive test method appropriate for the circumstance of South Korea. The purpose of this study is to compare and analyze estimated error of compressive strength in single-story structures comprised of vertical and horizontal reinforced concrete members using the impact testing method and rebound hardness method, which are nondestructive test methods, and to review on-site applicability of these methods. Based on compressive strength of the structures estimated, overall mean error was 21.2% for the impact testing method and 15.6% for the rebound hardness method. The necessity of a reliable diagnostic method based on compound nondestructive test methods to increase accuracy of estimation was confirmed.

• The Korean Journal of Applied Statistics
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• v.30 no.4
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• pp.503-512
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• 2017

In test with multiple choices, it is necessary to have the position of correct answers of each question spreaded evenly over all the questions in order to minimize the influence of answering tendency of test takers with preference to specific position of multiple choices. The scores of tests with correct answers in specific positions would not reflect exactly the academic aptitude of examinees who do not know correct answers but have the biased answering tendency. In this paper, we have randomness test for the positioning of correct answers at the 2017 College Scholastic Ability Test (CSAT) using Bartels rank test, the Wald-Wolfowitz runs test, the turning point test, the Cox Stuart trend test, the difference sign test and the Mann-Kendall tank test, etc. We also do independence test between the location of correct answer and the allocation of score in each question, for it may result in overestimating the test-taker with specific position preference in marking correct answers.