• Journal of The Korean Association For Science Education
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• v.29 no.4
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• pp.414-422
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• 2009

In this study, we investigated the influences of students' motivational characteristics on the processes of learning density concept using a discrepant event. The participants were 642 seventh graders from two middle schools. Tests of failure tolerance, self-efficacy and mastery/performance goal orientation were administered as pretests. A preconception test was also administered. The intervention was the students' individual study of the density concept with a worksheet that was designed to incorporate the major steps of conceptual change learning. The tests of attention, effort and conceptual understanding were administered as post-tests. The responses of 203 students who had been found to possess the target misconception were analyzed. The results of a path analysis revealed that students' motivational characteristics variables did not influence cognitive conflict. Failure tolerance and mastery goal orientation, however, influenced conceptual understanding via situational interest, attention and effort. Self-efficacy influenced conceptual understanding via effort. Performance goal orientation negatively influenced conceptual understanding via attention and effort. Cognitive conflict influenced conceptual understanding directly as well as indirectly via situational interest.

• Journal of The Korean Association For Science Education
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• v.28 no.6
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• pp.675-684
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• 2008

This study investigated the effects of the prescribed instructional strategy for reducing students' connecting errors in learning chemistry concepts with multiple external representations by students' field independence-dependence. Seventh graders (N=126) at a coed middle school were assigned to control and treatment groups. The students learned "Boyle's Law" and "Charles's Law" for two class periods. Results revealed that the students in the treatment group scored significantly higher than those in the control group in a conception test. The scores of the treatment group were significantly higher than those of the control group in a motivational learning test, especially in 'attention' of the test. However, there was no significant interaction between the instruction and students' field independence-dependence in the two tests. Most students in the treatment group perceived the instruction positively in cognitive and motivational aspects.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.193-200
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• 2007

This study investigated the effects of situational context feedback in CAI upon students' conceptual understanding, science learning motivation, and the perception of CAI. Seventh graders (N = 114) from a coed middle school in Incheon were assigned to the situational context feedback CAI (SCF-CAI), the feedback CAI (F-CAI) and the CAI groups, and were taught about ‘three states of matter' and ‘motion of molecules' for 8 class hours. Prior science achievement test score used as a blocking variable. Two-way ANCOVA results revealed that the conceptual understanding test scores of the SCF-CAI group were significantly higher than those of the other groups. For the higher achievers, the scores of the F-CAI group in science learning motivation test were significantly higher than those of the CAI group. However, there was no significant difference among the lower achievers of three groups. The higher achievers in the SCFCAI and the F-CAI groups perceived the CAI more positively than those of the CAI group. The lower achievers in the FCAI group perceived the CAI more negatively than those of the other groups. Educational implications are discussed.

• Journal of The Korean Association For Science Education
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• v.18 no.2
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• pp.173-182
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• 1998

This study investigated the influences of metacognitive learning strategies upon 6th-graders' achievement, science process skill, use of cognitive strategies, use of metacognitive strategies, self-efficacy, intrinsic value, attitude toward science class, and scientific attitude. The metacognitive learning strategies were developed on the basis of previous results and modified in a pilot study. Before the instructions, a pretest of motivation was administered, and used as a blocking variable. The score of previous achievement test was used as covariates for achievement and science process skill. Tests of use of cognitive strategies, use of metacognitive strategies, self-efficacy, intrinsic value, attitude toward science class, and scientific attitude were also administered, and their scores were used as covariates. After the instructions, a researcher-made achievement test, the Middle Grades Integrated Science Process Skills Test, and post-tests of above variables were administrated. Two-way ANCOVA results revealed that the scores of the treatment group were significantly higher than those of the control group for all tests except for science process skill. No interactions between the treatment and the level of the previous motivation were found. Educational implications are discussed.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.376-384
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• 2006

The purposes of this study were to analyze the frequency and type of volition strategy, according to achievement level, employed by students with high learning motivation, and to identify the role volition strategy plays in keeping students motived to learn science. To accomplish these aims, two groups of students(each containing three members) were selected. Students in the two groups both had the same cognitive level and high learning motivation. However, one group's science achievement was high, and the other was low. Through interviews and class observations, volition strategies students in the two groups used when they encountered hindrances in science learning were compared. Results of the study revealed a relationship between achievement level and volition strategy. Students showed differences in the frequency and types of volition strategies used according to science achievement. It was found that students with higher achievement levels used volition strategies more often to overcome hindrances in science learning than those with lower achievement levels. Furthermore, students with higher achievement levels generally used internal mind control strategies while those with lower achievement levels used environmental control strategies. Lastly, findings found that the types of volition strategies used by lower achievement level students were very limited.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.216-226
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• 2000

This paper presents a new method to synthesize timed asynchronous circuits directly from the specification without generating a state graph. The synthesis procedure begins with a deterministic signal transition graph specification with timing constraints. First, a timing analysis extracts the timed concurrency and timed causality relations between any two signal transitions. Then, a hazard-free implementation under the timing constraints is synthesized by constructing a precedence graph and finding paths in the graph. The major result of this work is that the method does not suffer from the state explosion problem, achieves significant reductions in synthesis time, and generates circuits that have nearly the same area as compared to previous methods.

• Korean Journal of Human Ecology
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• v.17 no.4
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• pp.693-705
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• 2008

본 연구는 인터넷 사용동기에 근거한 온라인 시장을 세분화하고자 하였다. 표본은 미국 남서부지역의 대학생으로 총 219명의 Y세대 소비자로 구성되었다. 자료분석을 위해 군집분석(Cluster Analysis)과 분산분석(ANOVA)을 사용하였다. 군집분석결과, 온라인소비자는 3개의 세분시장 즉, "쾌락적 소비자", "실용적 소비자", "비능동적 소비자" 집단으로 분류되었다. 개인적 특성 중, 성별과 연령에 따라 세 집단별 유의한 차이가 없었으나, 능동적 소비자 집단 (쾌락적소비자, 실용적 소비자)이 비능동적 소비자 집단보다 인터넷 사용시간과 온라인쇼핑에 드는 비용을 더 많이 소비하는 것으로 나타났다. 온라인구매성향에 있어서, 전반적으로 충동구매성향이 낮지만, 세 집단별 통계적으로 유의한 차이를 보여, 쾌락적 소비자가 가장 높았고, 다음은 실용적 소비자, 비능동적 소비자 순이었다. 계획구매성향은 전반적으로 높았으며, 쾌락적 소비자와 실용적 소비자 두 집단이 비능동적 소비자보다 계획구매성향이 더 높게 나타났다. 또한, 온라인구매의도는 실용적소비자가 가장 높았으며, 다음은 쾌락적 소비자, 비능동적 소비자 순이었다. 구체적으로 상품군별 구매의도차이를 검증한결과, 실용적소비자는 "책 또는 잡지", "액세서리와 보석"에 대한 온라인 구매의도가 가장 높은 반면, 쾌락적 소비자는 "여행티켓 또는 예약", "오락 및 여가상품"에 대한 온라인 구매의도가 가장 높은 경향을 보였다. 따라서, Y세대 소비자를 위한 온라인 시장세분화에 따른 차별화된 마케팅 전략이 논의되었다.

• Journal of KIISE:Software and Applications
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• v.27 no.4
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• pp.357-369
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• 2000

SMIL(Synchronized Multimedia integration Language) allows integrating a set of independent multimedia objects into a synchronized multimedia presentation. In this paper, I propose modeling rules, formal models, modeling function and an algorithm for SMIL documents using use case diagram and sequence diagram of UML(Unified Modeling Language), It will be used the use case diagram and collaboration diagram for object-oriented visualizing tool to describe the temporal behavior of the presentation. The main contribution of this paper is that developers of SMIL documents easily generate them using this rules and algorithm. And, the formal models and modeling functions provide an environment for processing object-oriented documents.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.3
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• pp.289-300
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• 2003

Traditional kernel-level communication systems for clusters are dependent upon computing platforms. Futhermore, they are not easy to use and do not provide various functions for clusters. This paper presents an architecture and various implementation issues of a kernel-level communication system, KCCM(Kernel level Cluster Communication Module), for linux cluster. The KCCM provides asynchronous communication services as well as standard synchronous communication services using send and receive. The KCCM also automatically detects and recovers connection failures at runtime. This allows programmers to use KCCM when they build mission critical applications over TCP-based connection-oriented communication environments. Having developed using standard socket interfaces, it can be easily ported to various platforms. The experimental results show that the KCCM provides good performance for asynchronous communication patterns.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.3
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• pp.144-154
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• 2001

다중 결합 질의에 포함된 다수의 결합 연산지를 효율적으로 처리하기 위해 서는 효율적인 병렬 알고리즘이 필요하다. 최근 다중 해쉬 결합 질의의 처리를 위해 할당 트리를 이용한 방법이 가장 우수한 것으로 알려져 있다. 그러나 이 방법은 실제 결합 시에 할당 트리의 각 노드에서 필연적인 지연이 발생되는 데 이는 튜플-시험 단계에서 외부 릴레이션을 디스크로부터 페이지 단위로 읽는 비용과 이미 읽는 페이지에 대한 해쉬 결합 비용간의 차이에 의해 발생하게 된다. 이들 사이의 실행시간을 가급적 일치시키기 위한 '페이지 실행시간 동기화'기법이 제안되었고 이를 통해 할당 트리 한 노드 실행에 있어서의 지연 시간을 줄일 수 있었다. 하지만 지연 시간을 최소화하기 위해 할당되어질 프로세서의 수 즉, 페이지 실행시간 동기화 계수(k)는 실제 결합 시의 결합률에 따라 상당한 차이를 보이게 되고 결국, 이 차이를 고려하지 않은 다중 해쉬 결합은 성능 면에서 크게 저하될 수밖에 없다. 본 논문에서는 결합 이전에 어느 정도의 결합률을 예측할 수 있다는 전제하에 다중 해쉬 결합 실행 시에 발생할 수 있는 지연 시간을 최소화 할 수 있도록 결합률에 따라 최적의 프로세서들을 노드에 할당함으로서 다중 해쉬 결합의 실행 성능을 개선하였다. 그리고 분석적 비용 모형을 세워 기존 방식과의 다양한 성능 분석을 통해 비용 모형의 타당성을 입증하였다.