• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.563-570
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• 2005

This study investigated the relationships among middle school students' understanding about the nature of scientific knowledge, conceptual understanding, and learning strategies. Grade 7 students (N=162) in Incheon completed the nature of scientific knowledge scales (NSKS) and a learning strategy questionnaire. After learning density by way of a CAl program, a conception test was administered. Results indicated that students' conceptual understanding and both deep and surface learning strategies were significantly correlated to their understanding about the nature of scientific knowledge. A cluster analysis was used to classify students on the basis of their deep and surface learning strategies. Three clusters of students with distinctive learning strategy patterns were found; high deep-low surface strategy (cluster 1), low deep-high surface strategy (cluster 2), and high deep-high surface strategy (cluster 3). One-way ANOVA results revealed that the scores of cluster 3 were significantly higher than those of the others in the NSKS and the conception test. Additionally, cluster 1 also performed better than cluster 2 in the conception test. Lastly, educational implications were discussed.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.305-308
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• 2006

Magnetic flux leakage (MFL) pigs are traditionally used for the detection of gross corrosion on steel pipelines used for the transmission of natural gas. Alternative nondestructive evaluation (NDE) modalities are required for the detection of stress corrosion cracking (SCC) which tends to exist in colonies oriented axially along the length of the pipeline. This paper describes the use of multiphase rotating magnetic fields in the remote region of the probe as a possible SCC detection mechanism. Details of a prototype pig and test rig are given and the challenges associated with the finite element modeling of the device are discussed. Initial experimental results show that this novel NDE modality is sensitive to axially oriented tight cracks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.449-455
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• 2004

This paper presents a novel defect detection method for one chip RF front end with fault detection circuits using input matching measurement. We present a BIST circuit using 40.25{\mu}m$ CMOS technology. We monitor the input transient voltage of the RF front end to differentiate faulty and fault-free RF front end. Catastrophic as well as parametric variation fault models are used to simulate the faulty response of the RF front end. This technique has several advantages with respect to the standard approach based on current test stimulus and frequency domain measurement. Because DUT and fault detection circuits are implemented in the same chip, this test technique only requires use of digital voltmeter (RMS meter) and RF voltage source generator for simpleand inexpensive testing.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.31-36
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• 2000

본 연구에서는 멀티미디어 환경에서 정보 제시 유형이 정보 처리에 어떤 영향을 미치는지를 알아보고자 하였다. 초등학교 아동을 대사으로 하여 텍스트와 나래이션을 제시한 조건, 텍스트와 애니매이션을 제시한 조건, 애니매이션과 나래이션을 제시한 조건에 따라 학습정도가 어떻게 달라지는지를 알아보았다. 학습 수행 평가는 학습자료를 보여주고 즉시 검사하였고, 학습한 후 일주일이 지난 후에 지연검사를 하였다. 그 결과 두 검사 모두에서 애니매이션과 나래이션을 제시한 조건이 다른 두 조건에 비해 효율적인 학습 수행 결과를 보였다. 이러한 결과는 아동에게 있어서 단일 매체(텍스트)로 정보를 제시하는 것보다는 다중매체(텍스트, 애니매이션)로 정보를 처리할 수 있도록 제시하는 것이 학습에 효과적임을 보요준다. 또한 이러한 결과는 기존의 이중보호이론과 작용기억이론을 지지해 준다.

• Journal of the Korean Magnetics Society
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• v.10 no.6
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• pp.302-309
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• 2000

An MFL (Magnetic Flux Leakage) testing system has been developed in order to inspect the non-metallic inclusions in the thin steel sheets. We have made a differential type flux-gate magnetometer using the measurement of apparent coercive field strength of soft magnetic core. The specifications of the electromagnet was determined using FEM software, and MFL testing system with 3 axis degree of freedom was constructed. The feasibility testing for non-metallic inclusion was shown using the system. By digitizing MFL signal and using 2-D graphic display, we could identify various surface defects other than the inclusions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.601-604
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• 2007

In this paper dose a laver surface check using a real time image process. This system does false retrieval of a laver at a laver production line. At first, a laver image was read in real time using a CCD camera. In this paper, we use an area scan CCD camera. Image is converted into a binary code image using a high-speed imaging process board afterwards. A laver feature is extracted by a binary code image. Surface false retrieval is finally executed using a laver feature. In this paper, we use an area feature of a laver image.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.1-9
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• 2001

This paper proposes an inspection algorithm for micro ball grid array ($\mu$BGA) solder balls. This algorithm is motivated by the difficulty of finding defect balls by human visual inspection due to their small dimensions. Specifically, it is developed herein an automated vision-based inspection algorithm for $\mu$BGA's, which can inspect solder balls not only for so-called two dimensional errors, such as missings, positions and sizes, but also for height errors. The inspection algorithm uses two dimensional images of $\mu$BGA obtained through special blue illumination, and processes them with a rotation-invariant sub algorithm. It can also detect height errors when a two-camera system is available. Simulation results show that the proposed algorithm is more efficient in detecting ball defects compared with the conventional algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1136-1140
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• 2007

In this paper dose a laver surface check using a real time image process. This system does false retrieval of a laver at a laver production line. At first, a laver image was read in real time using a CCD camera. In this paper, we use an area scan CCD camera. Image is converted into a binary code image using a high-speed imaging process board afterwards. A laver feature is extracted by a binary code image. Surface false retrieval is finally executed using a laver feature. In this paper, we use an area feature of a laver image.

• Journal of Korea Ship Safrty Technology Authority
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• s.28
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• pp.78-89
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• 2010

항만국통제는(Port State Control)은 자국 항만 또는 수역 내에서 기준미달선을 제거하기 위하여 선박이 외국항에 기항하였을 때 해당 항만국의 검사관(Port State Control Officer)이 승선하여 그 선박이 국제협약 또는 항만국의 규정에 적합하게 건조, 정비 및 운용되고 있는지를 확인하고 결함사항이 발견된 선박에 대하여 억류 등의 제제조치를 가하는 제도이다. 최근의 항만국통제는 기항 선박에 대한 Target Matrix를 활용한 점검대상 선박 선정, 집중점검프로그램 운용 및 목표 점검율 상향조정 등으로 항만국통제 활동은 점점 더 강화되고 있다. 우리공단 검사선박의 경우 PSC에 의한 출항정지 척수가 2006년 1척, 2007년 2척 그리고 2008년 4척으로 점차 증가하는 경향을 보이고 있다. 따라서 공단 검사선박의 출항정지율 저감을 위한 방안을 개발하기 위하여 Paris MOU, Tokyo MOU 그리고 USCG의 최근 PSC 점검동향과 우리 공단의 검사선박중 출항정지 선박 및 지적된 결함사항에 대하여 조사 분석한 결과 최근 7년간 출항정지 당한 선박 10척중 6척이 도입선과 2척이 탈급선이고 그리고 주요 지적사항으로는 만재흘수선 관련 결함사항이 가장 많이 지적되었음으로 분석되었다. 따라서 그러한 분석 결과를 바탕으로 공단 검사선박의 출항정지율 저감을 위한 대책을 검토하고 새로 도입되거나 개선되어야 할 점 등에 대한 안을 제시하였다.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.74-82
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• 2010

Purpose : The Dipslide culture test is a rapid method for diagnosis of urinary tract infection (UTI). The aim of this study is to determine the diagnostic availability of a urine Dipslide test for evaluation of UTI in febrile children. Methods : Urine specimens from 151 febrile infants were inoculated by a routine blood agar urine culture method and the Dipslide test at the same time. Following incubation for 16-24 hours, the results of the Dipslide test were read at the next visit. Both results of Dipslide and those of routine culture were compared. Results : The mean age of subjects was 15${\pm}$10.6 months. There were 150 infants (99.3%) who had fever with a mean duration of 2.6${\pm}$2.6 days. Thirty two infants (21.2%) were diagnosed as having UTI. Sensitivity and specificity of Uricult Trio CLED medium were 59.4% and 84.8%, respectively. Sensitivity and specificity of Uricult Trio E. coli medium were 60.0% and 96.2%, respectively. The Pearson correlation coefficient between results of Uricult Trio CLED medium and urine culture was 0.438 (P=0.01). Correlation between results of Uricult Trio E. coli medium and urine culture was 0.617 (P=0.01). Conclusion : The Dipslide test requires only 16-24 hours with high specificity in terms of UTI caused by E. coli without the problems associated with specimen delay. This test seems to be helpful for exclusion of UTI in febrile infants and it may reduce unnecessary hospitalization and antibiotic use. However, further studies are required before the product can be recommended as a routine diagnostic tool.