• Journal of the Korean earth science society
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• v.23 no.2
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• pp.166-179
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• 2002

This study investigated preservice teachers' perceived constraints in implementing their ideal pedagogies and the influence of the teacher education program on their pedagogical beliefs changes. Unique features that the university-based coursework and field experiences had on preservice teachers' learning to teach were also explored. This preservice teacher education program employs constructivist aspects of teacher education and generates applications of constructivism to the practice of teaching. Major findings include: preservice teachers' having traditional pedagogy as the default, recovery of prior beliefs, constraints on implementing constructivist pedagogy, and being overly confident in themselves as teachers. With the influence of constructivist epistemology, these preservice teachers' pedagogical beliefs evolved and were refined over time as they incorporated various constructivist ideas. The benefits and influences of the M.Ed. program's theoretical coursework and the field experiences on these teachers' learning-to-teach experiences are addressed with rich data. The implications for teacher educators as well as for the instructional practices of preservice teacher education programs are discussed. Recommendations for future research are also presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Journal of Korea Technology Innovation Society
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• v.12 no.4
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• pp.687-714
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• 2009

In this paper, we study empirically the relations between financial constraints and dividend adjustment speed of innovative small and medium sized enterprises (SMEs) listed on Kosdaq Market of Korea Exchange. The main results of this study can be summarized as follows. Determinants suggested by the major theories of dividends, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend payout policy of Kosdaq SMEs. Lintner's dividend adjustment model indicates that Kosdaq SMEs have long run target payout ratio, and that Kosdaq SMEs adjust partially the gap between actual and target payout ratio each year. In the core variables of Lintner (1956) dividend adjustment model, past DPS has more effect than current EPS. These results suggest that Kosdaq SMEs maintain stable dividend policy which maintain past DPS level without corporate special reasons. Dividend adjustment speed of innovative Kosdaq SMEs is more fast than that of uninnovative Kosdaq SMEs, and dividend adjustment speed of financial unconstrained innovative Kosdaq SMEs is faster than that of financial constrained innovative Kosdaq SMEs. Futhermore, dividend adjustment speed of innovative Kosdaq SMEs classified by Small and Medium Business Administration is faster than that of unclassified innovative Kosdaq SMEs. The former is linked with financial policies and services like credit guaranteed service, venture investment fund, insurance program, and so on. In conclusion, past DPS and current EPS suggested by the Lintner's dividend adjustment model explain mainly dividend adjustment speed, and financial constraints explain also partially. Therefore, if managers of innovative Kosdaq SMEs can properly understand of the effects of financial constraints on dividend smoothing, they can maintain constantly dividend policy. This is encouraging result for Korea government as it has implemented many policies to commit to innovative Kosdaq SMEs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.215-222
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• 1993

A general method is proposed for stiffness analysis of the leaf springs only using the geometric data and Young's modulus of the leaf springs. In this method, an engineering beam theory and Castigliano's theory are applied for the derivation of the stiffness of the leaf springs. To show realiability and effectiveness of this method, the stiffness from the proposed method is compared with the results for various types of leaf springs. From these comparisons the proposed method has been proved to be effective and reliable to estimate the stiffness of the leaf springs.

• Journal of Korean Society of Rural Planning
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• v.6 no.2 s.12
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• pp.12-19
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• 2000

Irrigation pipeline networks consist mainly of buried pipes and are therefore relatively free from topographic constraints. Installation of irrigation pipeline systems is increasing since the systems have several advantages compared to open channel systems. To achieve economic design of pipeline networks, the layout should meet several conditions such as shortest path, maximum flow, and least cost. Graph theory is mathematical tool which enable to find out optimum layout for complicated network systems. In this study, applicability of graph theory to figure out optimum layout of irrigation pipeline networks was evaluated.

• Journal of English Language & Literature
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• v.55 no.1
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• pp.129-152
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• 2009

The paper aims to prove symmetries of the left and right edges of a morphological unit through the analysis of English blends. Blends are the words derived from two existing words by snipping the middle parts out and putting the rest together, such as smog (

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.175-178
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• 2005

We show that next-generation galaxy surveys such as KAOS (the Kilo-Aperture Optical Spectro-graph)will constrain dark energy even if the baryon oscillations are missing from the monopole power spectrum and the bias is scale- and time-dependent KAOS will accurately measure the quadrupole power spectrum which gives the leading anisotropies in the power spectrum in redshift space due to peculiar velocities, the finger of God effect, as well as the Alcock-Paczynski effect. The combination of monopole and quadrupole power spectra powerfully breaks the degeneracy between the bias parameters and dark energy and, in the complete absence of baryon oscillations ($\Omega$b = 0), leads to a roughly $500\%$ improvement in constraints on dark energy compared with the monopole spectrum alone. As a result, for KAOS the worst case with no oscillations has dark energy errors only mildly degraded relative to the ideal case, providing insurance on the robustness of KAOS constraints on dark energy. We show that nonlinear effects are crucial in correctly evaluating the quadrupole and significantly improving the constraints on dark energy when we allow for multi-parameter scale-dependent bias.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2935-2944
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• 2009

This paper proposes Dual DBR(Drum-Buffer-Rope) system for a small-to-medium-sized PCB(Printed Circuit Board) manufacturing line. DBR method of TOC(Theory of Constraints) is an effective system for a small-to-medium-sized company to build production scheduling system. But to apply it to PCB line, it needs more technical consideration because of multiple constraints, looping process line and complex buffer management. This paper proposes an answer of these problems using Dual DBR to build production scheduling system more successfully. And it was confirmed that lead time was reduced more than 20% applying Dual DBR system to a domestic PCB manufacturing line actually.

• Nutrition Research and Practice
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• v.9 no.1
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• pp.63-70
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• 2015

BACKGROUND/OBJECTIVES: Use of nutrition labels in food selection is recommended for consumers. The aim of this study is to examine factors, mainly beliefs explaining nutrition label use in female college students based on the Theory of Planned Behavior (TPB). SUBJECTS/METHODS: The subjects were female college students from a university in Seoul, Korea. The survey questionnaire was composed of items examining general characteristics, nutrition label use, behavioral beliefs, normative beliefs, corresponding motivation to comply, and control beliefs. The subjects (n = 300) responded to the questionnaire by self-report, and data from 275 students were analyzed using t-test or ${\chi}^2$-test. RESULTS: The results showed that 37.8% of subjects were nutrition label users. Three out of 15 behavioral beliefs differed significantly by nutrition label use. Nutrition label users agreed more strongly on the benefits of using nutrition labels including 'comparing and selecting better foods' (P < 0.001), 'selecting healthy foods' (P < 0.05). The negative belief of 'annoying' was stronger in non-users than in users (P < 0.001). Three out of 7 sources (parents, siblings, best friend) were important in nutrition label use. Twelve out of 15 control beliefs differed significantly by nutrition label use. These included beliefs regarding constraints of using nutrition labels (e.g., time, spending money for healthy foods) and lack of nutrition knowledge (P < 0.001). Perceived confidence in understanding and applying the specifics of nutrition labels in food selection was also significantly related to nutrition label use (P < 0.001). CONCLUSIONS: This study found that the beliefs, especially control beliefs, suggested in the TPB were important in explaining nutrition label use. To promote nutrition label use, nutrition education might focus on increasing perceived control over constraints of using nutrition labels, acquiring skills for checking nutrition labels, as well as the benefits of using nutrition labels and receiving support from significant others for nutrition label use.

• 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.