• Nuclear Engineering and Technology
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• v.19 no.1
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• pp.1-9
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• 1987

The fracture toughness of SA 533 Grade B Class 1 steel has been studied with the Charpy impact test specimens in a range of temperature between -4$0^{\circ}C$ and 288$^{\circ}C$. The dynamic fracture toughness is measured by the instrumented precracked Charpy impact test while the static fracture toughness is by the 3-point bend test based on the unloading compliance method. The results are compared with the data obtained from the large specimens. It is known through the studies that temperature dependence of the appropriate (a low bound) value of the fracture toughness can be estimated by taking the static fracture toughness above the transition temperature and the dynamic fracture toughness below the temperature and it is also shown that the tests are satisfied with the requirements of ASTM E 813 when the side-groove is more than 14%.

• Transactions on Electrical and Electronic Materials
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• v.2 no.4
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• pp.1-6
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• 2001

In this paper, a 1.5 V high-gain high-frequency CMOS complementary operational amplifier is presented. The input stage of op-amp is designed for supporting the constant transconductance on the Input stage by consisting of the parallel-connected rail-to-rail complementary differential pairs. And consisting of the class-AB rail-to-rail output stage using the concept of elementary shunt stage and the grounded-gate cascode compensation technique for improving the low PSRR which was a disadvantage in the general CMOS complementary input stage, the load dependence of open loop gain and the stability of op- amp on the output load are improved, and the high-gain high-frequency operation can be achieved. The designed op-amp operates perfectly on the complementary mode with the 180° phase conversion for a 1.5 V supply voltage, and shows the DC open loop gain of 84 dB, the phase margin of 65°, and the unity gain frequency of 20 MHz. In addition, the amplifier shows the 0.1 % settling time of .179 ㎲ for the positive step and 0.154 ㎲ for the negative step on the 100 mV small-signal step, respectively, and shows the total power dissipation of 8.93 mW.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.406-414
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• 2019

The purpose of this study was to investigate how educational experience (teaching experience, experience participating in the Teacher Learning Community, curriculum training experience, and innovative experience working in school) of elementary school teachers affects the recognition and execution of curriculum and textbooks. For this purpose, the results of a questionnaire survey for elementary school teachers were analyzed by performing T-tests, One-Way ANOVA, correlation analysis, and regression analysis. The results were as follows. First, according to the teacher's educational experience, there were statistically significant differences in the recognition and execution of curriculum reorganization, and the recognition and dependence on textbooks. Second, there were statistically significant correlations among such variables as recognition and implementation of curriculum reorganization, and the recognition and dependence on textbooks. Third, the teacher's educational experience had a significant impact on curriculum reorganization and the dependence on textbooks. Curriculum restructuring in elementary schools is not an end in itself. What is also needed is to find and implement the best class plans for promoting the .meaningful growth and development of elementary school students. This study suggests that the dependence on textbooks should be lowered and the curriculum should be actively reorganized, and teachers should develop their expertise based on extensive educational experience.

• Journal of The Korean Association For Science Education
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• v.26 no.2
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• pp.191-199
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• 2006

This study investigated the influence of time to draw students' mental models and students' field dependence-independence on learning the particulate nature of matter with multiple representations. Seventh graders (N=295) at two middle schools were assigned to control, after-drawing, and before-drawing groups. The students learned "Boyle's Law" and "Charles's Law" for two class periods. Results revealed that the scores of a test on conceptual understanding for the two drawing groups were significantly higher than those for the control group. However, there was no significant interaction between the instruction and students' field dependence-independence in the scores of the test on conceptual understanding. In 'novelty' on a situational interest test, field independent students in the two drawing groups scored significantly higher than those in the control group. The scores for field independent students in each group were similar, while field dependent students in the before-drawing group scored lower than those in the control and after-drawing groups in 'attention demand' on the situational interest test. It was found that most students positively perceived after-drawing or before-drawing, but field independent students in the before-drawing group were more apprehensive about the activities than those in the after-drawing group.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.168-171
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• 2000

VO$_2$ceramics exhibiting a negative temperature coefficient (NTC) of resistivity have been widely used as temperature dependence resistors. The NTC effect similar to $VO_2$ceramics was observed when a low-thermal-expansion ceramic matrix was loaded near the percolation threshold with conductive metal particles. The resistivity in a composite made from silica glass and 20 vol% Ag filler suddenly decreased from $10^{-7}$ to $10^3\;\Omega$cm at about $300^{\circ}C$.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.703-707
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• 2001

A performance analysis of a SOFC/MGT hybrid system has been carried out for concept design. Thermo-dynamic models for each component being able to describe electrochemical characteristics and heat and mate-rial balance are proposed. Estimated is the power capacity of a SOFC suitable for the hybrid operation with a 5kW class MGT. Effects of current density and operating pressure are also investigated. Electric efficiency showed weak dependence on operating pressure and current density. It is desirable that the SOFC operates at high current density in manufacturing cost's point of view though operating with high current density slightly decreases the electric efficiency find specific power.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.713-716
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• 2005

In this paper, in order to identify and recognize attack patterns, we propose a Bayesian classification using frequent patterns. In theory, Bayesian classifiers guarantee the minimum error rate compared to all other classifiers. However, in practice this is not always the case owing to inaccuracies in the unrealistic assumption{ class conditional independence) made for its use. Our method addresses the problem of attribute dependence by discovering frequent patterns. It generates frequent patterns using an efficient FP-growth approach. Since the volume of patterns produced can be large, we propose a pruning technique for selection only interesting patterns. Also, this method estimates the probability of a new case using different product approximations, where each product approximation assumes different independence of the attributes. Our experiments show that the proposed classifier achieves higher accuracy and is more efficient than other classifiers.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.50-62
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• 1994

Opium, morphine and rotated natural and synthetic opiates have been used since antiquity, and to the present, for the relief of moderate and severe pain. Morphine and pharmacologically related drugs, however, produced an array of undesired or dangerous side effect that limit their use as analgesics. Prominent among the limiting side effects are constipation, respiratory depression, release of prolactin, and liability for the production of drug dependence. It was our aim to develop, if possible, a drug or class of drugs with analgesic activity similar to that of morphine, but without the serious side effects associated with morphine. Our overall strategy was to take advantage of advancing knowledge concerning multiple types of opioid receptors, to develop ligands selective for the delta type receptors, to determine whether delta receptor agonists offer advantages over mu agonists, then to design compounds with pharmacokinetic properties compatible with practical therapeutic application. All but the last of these objectives have been realized.

• IE interfaces
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• v.15 no.1
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• pp.10-19
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• 2002

New trends such as electronic commerce, virtual organizations, e-business applications, etc. increase the dependence of production management on information software systems and contribute to the needs for global, distributed object systems. This paper presents a component based approach for production management systems under the multi-tier distributed information system architecture using UML(Unified Modeling Language), CORBA(Common Object Request Broker Architecture) and XML(eXtensible Markup Language) technologies, and propose rules for mapping a UML class diagram to a XML DTD (Document Type Definition). And we adapt it to the prototype system implementation. The components are implemented by CORBA and we use XML messages for the information exchange between components.

• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1479-1493
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• 1998

C++ 프로그램을 병렬 실행시키려면 재구성 컴파일러가 함수 호출로 발생하는 요약된 정보를 수집해야 한다. 객체의 참조 매개변수를 사용하는 경우와 객체의 참조를 반환하는 메소드에 대해서 메소드간의 요약된 정보를 발견하여 병렬성을 검출하는 것은 어렵다. 본 논문에서는 순차 C++ 프로그램을 병렬 프로그램으로 변환하기 위해 클래스 인터페이스 내에 메소드간의 관계를 명시하는 병렬 정보 GERINFPO절과 순서 정보 SEQ절을 삽입하므로서 명시적인 병렬성을 얻고 재구성 컴파일러는 명시된 정보를 이용하여 프로그램내에 내재한 묵시적 병렬성을 얻는 방법을 제안한다. 또한 본 논문에서 제시하는 종속 분석 방법을 이용하여 순차 C++ 프로그램을 병렬 코드로 변환하는 병렬코드 변환기를 구현하였다.