• 한국수학교육학회지시리즈A:수학교육
• /
• 제47권3호
• /
• pp.261-271
• /
• 2008

First, we have reviewed the concepts of technology as tools, artefacts, and instruments and then introduced constructivism, mathematical communication, and anthropological views on the technology as instruments. Next, this study has supported the anthropological studies considering the facts that learners develop instrumented schemes in the interactions among learners, tools, and mathematical knowledge, and has discussed the change of paradigm. Finally, we have argued that curriculum, epistemology, and relevant studies should be changed to the new paradigm, and then we have discussed that the change of paradigm should be established on the nature, the purpose, the contents, and the assessment in mathematics learning and the role of teachers.

• Geomechanics and Engineering
• /
• 제5권3호
• /
• pp.195-221
• /
• 2013

A centrifuge model study is carried out to investigate the behavior of pile subject to negative skin friction induced by pile installation, ground water drawdown and surcharge loading. A single end-bearing pile is examined as the induced negative skin friction would induce the most severe stress on the pile structural material as compared to friction piles. In addition, the behavior of the pile under simultaneous negative skin friction and dead/live loads is examined. To facilitate detailed interpretations of the test results, the model setup is extensively instrumented and involves elaborate test control schemes. To further examine the phenomenon of negative skin friction on an end-bearing pile, finite element analyses were conducted. The numerical analysis is first validated against the centrifuge test data and subsequently extended to examine the effects of pile slenderness ratio, surcharge intensity and pile-soil stiffness ratio on the degree of mobilization of negative skin friction induced on the pile. Finally experimental and numerical studies are conducted to examine the effect of applied transient live load on pile subject to negative skin friction.