• Journal of Fisheries and Marine Sciences Education
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• v.19 no.3
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• pp.390-402
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• 2007

According to the paradigm of Neo-liberalism, the issue of ability grouping has grown more and more in education of Korea. And because of the influence of ability grouping, now ability grouping is enforcing partially in the subjects of English and Mathematics. But ability grouping is going to expand to the all subjects. So, it is very important that how teachers and students are recognize about partial ability grouping in the subjects of English and Mathematics. Because that information about partial ability grouping can guide direction for the future educational policy. The purpose of this study was to actually analyze teacher's and students' recognition of partial ability grouping in the subjects of English and Mathematics. To accomplish this purpose, 622 middles school students and 552 teachers were sampled. As a tool of investigation, questionnaires about teacher's and students' recognition of partial ability grouping had made by researcher of this study were used. And as processing of data, t-test, F-test, Scheff-test were used. The result of this study is as follow. First, teachers who are experiencing ability grouping recognized more negative about ability grouping than teachers who are not experiencing ability grouping. Second, students who have low ability recognized more negative about ability grouping than students who have high ability. Third, teachers who are experiencing ability grouping recognized more ineffective about ability grouping than teachers who are not experiencing ability grouping. Fourth, students who have low ability recognized more ineffective about ability grouping than students who have high ability.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.9-15
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• 2004

3kW grid connected PV(photovoltaic) systems have been constructed for evaluating and analyzing performance of PV system at FDTC(field demonstration test center) in Korea, PV systems installed in FDTC have been operating and monitored since November 2002. As climatic and irradiation conditions have been varied through long-term field test, data acquisition system has been constructed for measuring performance of PV system to observe the overall effect of environmental conditions on their operation characteristics. The performance of PV systems has been evaluated and analyzed for component perspective(PV array and power conditioning system) and global perspective(system efficiency, capacity factor, and electrical power energy) by field test. By the results, it is very important to develop optimal design technology of grid connected PV system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1159-1162
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• 2003

Recently we suffered lot of failures of polymer surge arresters made by same manufacture after one year field operation. In order to set up countermeasures we investigated the causes of failures. We extracted faulted arresters and sound ones which were installed in same pole with faulted ones for the electrical test and dissection. 44 arresters were removed from 8 branch offices. Almost all of faulted arresters hadtracking damage on the interface between inner module and housing and the surface of inner module was very rough and irregular. It was possible to occur moisture ingress into the interface between inner module and housing due to the void of the interface and non tight sealing caps. Lots of sound arresters were failed during the moisture ingress test. This result must relate with tracking damage of faulted arresters. Therefore we can say that arresters had poor interface and sealing system. But we could not found aging and defects of ZnO elements because the electrical performance except moisture ingress test of arresters showed good.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.6-14
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• 1996

In this paper we present an algorithm to discriminate an underwater target under track against an acoustic counter-measure(ACM) source, based on a sequential hypothesis test. The ACM source is separated from the target under track and generates, while drifting, measurements with false range and Doppler information. The purpose of the ACM is to mislead the target-tracking and to help the true target evade a pursuer. The algorithm uses as a test statistic a function of the innovation sequences from extended Kalman filters to estimate the target dynamics and the drifting position of the ACM source. Numerical experiments on various scenarios show that the proposed algorithm discriminates the target against an ACM source very fast with a high probability of success.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.580-588
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• 2009

A Missile Warning Radar is an essential sensor for active protection system to detect antitank missile in all weather environments. This paper presents the design, development, and test results of L-band pulsed Doppler radar system for main battle tank. This radar system consists of 3 LRUs, which include antenna unit, transmitter and receiver unit and radar signal & data processing unit. The developed core technologies include the patch antenna, SSPA transmitter, coherent I/Q detector, DSP based Doppler FFT filter, adaptive CFAR, SIW tracking capability, and threat decision. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test.

• Korean Journal of Biological Psychiatry
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• v.9 no.2
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• pp.112-119
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• 2002

Object:This study was to investigate the difference of speech perception ability in schizophrenic patients, and depression patients in order to explore trait-dependent speech perception ability of each disorder. Methods:The speech perception ability was assessed with masked speech tracking test(MST) in schizophrenic patients(N=31), depression patients(N=25), and normal controls(N=21). The continuous performance test(CPT) and sentence repetition test(SRT) were also used for assessment of attention and working memory. Results:The schizophrenic patients showed significant impaired MST performance, compared with depressive patients and normal controls. The performances of CPT and SRT were also more impaired in schizophrenic patients. The difference of MST performances between two patient group was cancelled out after consideration of differences in CPT & SRT performances. Conclusions:These results imply that schizophrenic patients have the impaired speech perception ability compared with depressive patients and normal controls. But speech perception ability was significantly influenced with CPT and SRT. For evaluation of pure speech perception ability, the more elaborate controlled study that excluded factors such as attention, working memory and intelligence is needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.45-54
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• 2006

General unmaned airship, in use of aviation photography, needs both airship -controller and camera-controller who work together in harmony. In oder to reduce this manpower and get the good Geographical Information Systems(GIS) data, it is necessary to use a autopilot controller which guides a exact path lines. This paper presents the autopilot control law base on classical PID control. Moreover, this paper shows the result of flight test, the procedure of gain tuning and LOS guidance algorism that is reduce a tracking error.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1526-1529
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• 1994

In hydro-generator, a groundwall insulation of stator windings gradually deteriorates due to mechanical, thermal, electrical and environmental stresses. These stresses combine to result in loose windings, delamination of the stator insulation and/or electrical tracking of the end winding, all of which can lead to stator insulation failures. Conventionally, off-line tests such as partial discharge measurement, DC/AC current test and ${\Delta}tan{\delta}$ test has been used for estimation of winding condition. However, off-line test requires large power supply and generator outage. In addition, major cause of insulation problems such as loose wedges and slot discharges may not be found with off-line diagnoses. This paper describes the on-line partial discharge measurement techniques in the generator stator windings. The experimental results from the UIAM #1 hydro-generator confirms a optimistic application of on-line generator diagnosis method as a reliable tool for evaluation of winding condition.

• Earthquakes and Structures
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• v.6 no.5
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• pp.539-560
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• 2014

Shaking tables are devices for testing structures or structural components models with a wide range of synthetic ground motions or real recorded earthquakes. They are essential tools in earthquake engineering research since they simulate the effects of the true inertial forces on the test specimens. The destructive earthquakes that occurred at the north part of Algeria during the period of 1954-2003 resulted in an initiative from the Algerian authorities for the construction of a shaking simulator at the National Earthquake Engineering Research Center, CGS. The acceleration tracking performance and specifically the inability of the earthquake simulator to accurately replicate the input signal can be considered as the main challenge during shaking table test. The objective of this study is to validate the uni-axial sinusoidal performances curves and to assess the accuracy and fidelity in signal reproduction using the advanced adaptive control techniques incorporated into the MTS Digital controller and software of the CGS shaking table. A set of shake table tests using harmonic and earthquake acceleration records as reference/commanded signals were performed for four test configurations: bare table, 60 t rigid mass and two 20 t elastic specimens with natural frequencies of 5 Hz and 10 Hz.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.2
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• pp.101-110
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• 2000

This study focuses on examination of the availability and effectiveness about application of the differential GPS methods for navigation and acquisition of the geo-spatial information. For this, the algorithms related to a navigation solution and differential GPS were implemented in MATLAB code, a number of software simulations on test model were carried out to assess its performance, comparing the results with those obtained from the commercial software. Expecially, the results coming from tracking test on test model of the OO's WADGPS which is the commercial real-time satellite-based augmentation system via geostationary satellite (GEOs), which has been investigated with those from the above GPS methods. And also, the accuracy of absolute positioning by Navigation solution and WADGPS before and after SA-off has been compared. The above results show that DGPS methods are very reliable and efficient methods for acquisition of the geo-spatial information.