• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.3
• /
• pp.485-491
• /
• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.

• English Language & Literature Teaching
• /
• v.12 no.1
• /
• pp.257-286
• /
• 2006

This paper investigates the effects of small group collaborative transcription activities on the improvement of university students' English listening ability. Based on the results of pre-tests, a class of 42 students was subdivided into 11 small homogeneous groups of three to four students. Each group was provided with 7 different news items to be transcribed. Means were compared between pre-test and post-test scores, followed by comparison of transcription errors in content and function words. Finally, students' perception and attitudes about the use of small group transcription for improving listening skills were qualitatively analysed and compared with pre- and post test results. It was found that post test scores highly correlated with improvement of listening ability. It was also found that groups of high degree of collaboration showed improvement in listening ability while lack of collaboration contributed to loss of interests in listening. Students who see process more important were found to make more contribution to the group success than those who place more emphasis on the results.

• Journal of Applied Reliability
• /
• v.14 no.4
• /
• pp.236-242
• /
• 2014

Since permanent magnet coupling transfers power by magnetic force without contact, it has little shock, vibration, noise. In case of overload, it protects a pump or a motor which is relatively important by slipping internally. In this study, failure analysis and test evaluation on the permanent magnet coupling have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement plan has been presented. Finally, reliability improvement is established by analysis of the test results of before and after acceleration test.

• Journal of Applied Reliability
• /
• v.16 no.4
• /
• pp.263-271
• /
• 2016

Purpose: A slurry pump for flue gas desulfurization system performs a role that discharges the slurry of a plaster shape in a thermal power plant. Since a slurry pump transfers the slurry by the centrifugal force, it has the friction wear in the impeller and liner because of the slurry. Methods: In this study, failure analysis and test evaluation on the slurry pump have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement design has been presented. Results: Reliability improvement is established by analysis of the test results of before and after acceleration test. Conclusion: This study can be provided to improve the product reliability through failure analysis of a slurry pump.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.3
• /
• pp.333-343
• /
• 2006

In this paper, the baseline-length information is directly modeled as a measurement for the Wald test, which speeds up the resolution convergence of the integer ambiguity of GPS carrier phase measurements. The convergent speed improvement is demonstrated using numerical simulation and real experiments. It is also shown that the integer ambiguities can be resolved using only four actual satellite measurements with very reasonable convergence speed, if the baseline-length information is used just like one additional observable satellite measurement. Finally, it is shown that the improvement of convergence speed of the Wald test is due to the increase of the probability ratio with the use of the baseline-length constraint.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1678-1688
• /
• 2008

In this study, dredging reclamation ground were performed to evaluate the ground improvement and liquefaction reduction effect with the result that standard penetration test(SPT) and piezo penetration test(CPT) before and after of improvement. Especially, the estimate center of the pile and factor of liquefaction safety to the position of ground around with the pile presented improvement of compaction for improved compaction of dredging reclamation ground.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2007.09a
• /
• pp.373-382
• /
• 2007

In the vertical drain method, discharge capacity is generally one of the most important factor which affect on the estimation of the drain efficiency. However, adopting the drain considering discharge capacity only is not sufficiently considered method so that systematic criteria for adoption is necessary to choose the most suitable drain. Therefore, this study represents the application method considering behavior of the ground and vertical drain which is coupled together and ground improvement efficiency analyzing various cases of discharge capacity test performed in the recent soft ground improvement projects. According to the analysis, most drains tend to satisfy the required discharge capacity. It presents that deformed shape of the drains and well resistance estimation along the ground settlement, improvement efficiency by water content ratio along the depth and shear strength obtained after ground improvement should be considered altogether with the discharge capacity to select the proper drain. Also, appropriate adoption of drain material considering the ground condition is vital through analyzing the field measured data and comparing the result of the discharge capacity test as various vertical drain materials are being constructed continuously.

• Journal of the Korean Society of Systems Engineering
• /
• v.15 no.2
• /
• pp.9-16
• /
• 2019

The most important task in acquiring the weapon system is to determine the required performance and to test & evaluate it. The importance of the weapon system by ROC (Required Operational Capability) is not considered, and system development and test evaluation are carried out. In addition, technical incidental performance is tested on the same basis as ROC in the test evaluation and determined according to the result. Development test and evaluation that evaluates technical ability is very important, but development agency is supervised and performed. In this paper, we propose a method to give weights considering the importance of ROC, a technical incidental performance determination and test procedure, and a improvement plan for the development and operational test & evaluation.

• Journal of Engineering Education Research
• /
• v.16 no.4
• /
• pp.15-20
• /
• 2013

The result of the English test for freshmen showed wide difference in the ability of students, which means the graded class is strongly required. This paper describes the case study about the graded English class that was carried out for the freshman. Every freshman must take an English placement test from problems bank and were classified according to the result of the test. In order to resolve the dissatisfaction of the high level students, the statutes of my university for credit were modified. In order to analyze the effect of the graded class, evaluation test using similar problems was carried out at the end of the semester. The effect of the graded class was analyzed by using the paired samples t-test method and there was a meaningful performance improvement at the average score. Additional improvements in the method of classification and credit granted were made by analyzing the results of the evaluation test and survey.

• Journal of Acupuncture Research
• /
• v.28 no.6
• /
• pp.43-51
• /
• 2011

Objectives : The purpose of this research was to investigate the effect of oriental medicine public-health program on frozen shoulder patients. Methods : Oriental medicine public-health program was done to 50 frozen shoulder patients who visited Eumseong-gun public health center. Oriental medicine treatment(twice a week for 12 weeks) and prevention-educaiton program was included in public-health program. The schedule was proceeded from 16th March 2010 to 3rd June 2010. The efficacy of program was measured by visual analog scale (VAS), ROM(range of motion), Apley scratch test and Life function score, sleep quality score of their first and last visit. Then we analyzed the improvement in the same group. Results : 1. In VAS change, program showed statistically significant improvement. 2. In ROM(flexion, extension, abduction, adduction) and apley scratch test, program showed statistically significant improvement. 3. In Life function score, program showed statistically significant improvement. 4. In sleep quality score, program also showed improvement, but didn't do statistical significans. Conclusions : The above results suggest that oriental medicine public-health program can be used as effective method for frozen shoulder's treatment and care.