• 대한수학교육학회지:수학교육학연구
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• 제27권4호
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• pp.747-764
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• 2017

초등학교 수학 수업에서 교사의 교과서에 대한 의존도가 높으며, 수학은 문제의 답을 구하는 것이라는 신념이 강하기 때문에 교과서에 제시되는 문제가 특히 중요하다. 이에 본 연구는 우리나라 초등학교 수학 교과서의 문제를 정량적, 정성적으로 분석하였다. 구체적으로, 1차 교육과정에서 2015 개정 교육과정까지 수학 교과서의 두 자리 수 범위의 받아올림이 있는 덧셈과 받아내림이 있는 뺄셈 관련 문제를 문제 빈도, 형태 및 수행 요구, 활용 주체의 정량적 차원에서, 문제의 표현과 맥락의 정성적 차원에서 각각 분석하였다. 연구 결과, 각 교과서에 제시된 문제는 교육과정 및 교육사조의 변화를 반영하며, 시대의 흐름에 따라 학생들의 문제해결, 추론, 의사소통 능력을 신장시키는 방향으로 변화하고 있는 것으로 파악되었다. 이와 같은 연구 결과로부터 교과서 집필 시 다루어야 할 문제와 관련한 몇 가지 시사점을 제안하였다.

• 전자공학회논문지A
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• 제28A권11호
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• pp.915-922
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• 1991

This research paper presents an ALU unit using 1.0$\mu$m CMOS technology capable of doing IEEE standard single and double precision floating poing calculation within 32ns (2 clock) at 60 MHz clock speed. This 32ns speed was achieved by using 9ns 1's complement arithmetic 54 bit carry select adder instead of previous 2's complement adders. On the first cycle, this adder is used for addition or subtraction and the second cycle uses this adder for rounding. This reduces the number of required adders from two to one. Speed improvement is 2 to 5 times compared with previous 40MHz design. Design goal was 60MHz, however, this unit is functioning at 80 MHz at room temperature.

• Clinical and Experimental Reproductive Medicine
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• 제29권4호
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• pp.295-302
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• 2002

Uterine cells carry out proliferation and differentiation for preparation the embryonic implantation during pregnancy. Therefore regulation of the cell proliferation is an essential step for uterine preparation, but there is not much information about the proliferation related genes in pregnant uterus. To identify these implantation specific genes, a PCR-select cDNA subtraction method was employed and got a few genes. One of the identified genes is a novel gene encoding oral tumor suppressor doc-1. To detect the doc-1 expression on the pregnant uterus, dot blotting, RT-PCR, and in situ hybridization were employed. Dot blotting revealed that doc-1 mRNA expression increase after implantation. During normal pregnancy, doc-1 mRNA expression was detected as early as day 1 of pregnancy with RT-PCR. Its expression was increased about 15 times after embryonic implantation. doc-1 transcript was localized in luminal epithelial cells but it was very faint during preimplantation. After starting the implantation, it localized in the stromal cells; heightened expression of doc-1 correlates with intense stromal cell proliferation surrounding the implanting blastocyst on day 6 morning. However in the decidualized cells, the intensity of localized doc-1 mRNA was weak. From those results, it is revealed that doc-1 express at pregnant uterus of the mouse. In addition it is suggested that doc-1 is the gene regulating the proliferation of the luminal epithelial cells and stromal cells during early implantation and decidualization.