• School Mathematics
• /
• v.15 no.4
• /
• pp.975-994
• /
• 2013

In this paper, we analyzed the utilization trend of technology in the secondary mathematics textbooks based on the 6th, 7th and 2007 revised mathematics curriculums in Korea. We analyzed 30, 60 and 90 mathematics books based on the 6th, 7th and 2007 revised mathematics curriculums respectively. The analysis focused on three aspects of using technology, i.e., contents areas in which technology used, technological tools and programs used, and methods of using technology in teaching and learning mathematics. The results shows that the frequency of using technology in mathematics books has been increased as mathematics curriculum has been revised. In the mathematics books based on th 6th curriculum, only 25 scenes were found, but in 7th and 2007 revised curriculum 248 and 355 scenes were found. In the 6th curriculum, calculators and graphing calculators were used mainly, but in the 7th and 2007 revised curriculum many kinds of technological tools and softwares were used including CAS, dynamic geometry software, spreadsheets, programming language, and the Internet. Especially the internet was used frequently in the 7th curriculum. And the methods of using technology has been diversified as time passed. In the 6th curriculum, the technology mainly used for introducing technology and simple calculation, but in the 7th and 2007 revised curriculum the technologies and software were also used for understanding mathematical laws, principles and concepts and students-centered exploring the mathematical properties.

• Journal of the Korean Society of Groundwater Environment
• /
• v.1 no.2
• /
• pp.90-99
• /
• 1994

Heterogeneous hydraulic conductivity in a flow domain is generated under the assumption that it is a random variable with a lognormal, spatially-correlated distribution. The hydraulic head and the conductivity in a groundwater flow system are represented as a stochastic process. The method of Monte Carlo Simulation (MCS) and the finite element method (FEM) are used to determine the statistics of the head and the logconductivity. The second moments of the head and the logconductivity indicate that the cross-covariance of the logconductivity with the head has characteristic distribution patterns depending on the properties of sources, boundary conditions, head gradients, and correlation scales. The negative cross-correlation outlines a weak-response zone where the flow system is weakly responding to a stress change in the flow domain. The stochastic approach has a potential to quantitatively delineate the zone of influence through computations of the cross-covariance distribution.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.147-150
• /
• 2008

The real road network is regarded as a grid, and the grid is divided by fixed-sized cells. The path-finding is composed of two step searching. First searching travels on the abstract graph which is composed of a set of psuedo vertexes and a set of psuedo edges that are created by real road network and fixed-sized cells. The result of the first searching is a psuedo path which is composed of a set of selected psuedo edges. The cells intersected with the psuedo path are called as valid cells. The second searching travels with $A^*$ algorithm on valid cells. As pruning search space by removing the invalid cells, it would be possible to reduce the cost of exploring on real road network. In this paper, we present the method of creating the abstract graph and propose a path-finding algorithm on the abstract graph for extracting search space before traveling on real road network.

• Journal of the Korean Electrochemical Society
• /
• v.3 no.1
• /
• pp.5-10
• /
• 2000

In the present work, corrosion rate W and corrosion potential tow were simultaneously measured as a function of relative humidity RH employing the electrochemical wet and dry method as an accelelated atmospheric corrosion method. The W versus (vs.) RH curve is classified into .three regions, namely, the first W plateau region, the second region of the linear relationship between logarithmic W and RH, finally, followed by an abrupt decay region. Based upon the atmospheric corrosion mechanism of mild steel, we introduced another diagram of $\varepsilon_{corr}$ vs. RH which is divided into three regions. In the first region, the corrosion scales are composed of single lepidocrocite-phase $(\gamma-FeOOH)$; in the second region, $\gamma-FeOOH$-phase coexists with magnetite-phase $(Fe_3O_4)$ in the scales and finally the oxide scales change into a single Fe304-phase in the third region. The three distinct regions of both representations share almost each other, which is validated by FT-IR (Fourier transform infra-red) analysis and surface observation. Both representations prove to be convenient and complementary for surveying the spectrum of the atmospheric corrosion of mild steel.

• Journal of Korea Spatial Information System Society
• /
• v.9 no.1
• /
• pp.31-43
• /
• 2007

Sensor data have the characteristics such as numerous and continuous data. Therefore, it is required to develop an index which could retrieve a specific sensor data efficiently from numerous sensed data. The index should have an efficient delete operation for the past data to support the data archiving. In this paper, we have proposed and implemented an index splitting technique to support the sensor data archiving. These splitted indexes compose of a virtual index (that is, index management component), which is shown as single tree from outside. Experimental results show that in the case of 100,000 insert operations the splitted index performs 8% better than the traditional TB-tree maximumly. And the splitted index outperforms TB-tree with retrieving queries when the region of query is small and the size of time domain is large.

• Journal of Educational Research in Mathematics
• /
• v.13 no.3
• /
• pp.403-428
• /
• 2003

This study intends to compare the mathematics contents included in the mathematics curriculum of Korea, California in USA, England, and Japan. The result of this comparison is that there are big differences on ranges, depths, and grades between mathematics contents in four countries' mathematics curriculum. In Korea, more contents are dealt in earlier grade and to higher level than other countries. And, these features are revealed more apparently in the area of algebra, analysis, and geometry than probability and statistics.

• Korean Journal of Optics and Photonics
• /
• v.20 no.6
• /
• pp.319-327
• /
• 2009

We introduce a new design technique by treating a two-group zoom lens system with a wide angle of view. First, the concept of the global optimization is introduced in the initial design stage, and from this, the global design technique is completed by analyzing and summarizing large quantities of modern design data. That is, we define the global structure function to achieve a new conceptual design technique for global optimization. And the function is put in a simple form by referring lots of patent data, manipulated with other algebraic equations, and solved finally such that we obtain the global solution region. The global solution region corresponds to the global optimization and suggests insightful systematized directions for the design of two-group zoom lens systems. These directions are attractive compared to global optimization.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.5
• /
• pp.1295-1302
• /
• 2010

This paper proposed indoor location recognition method based on RSSI(received signal strength indication) using the LVQ network. In order to verify the effectiveness of the proposed method, we performed experiments, and then compared to the conventional triangularity measurement method. In the experiments, we set up the system to the laboratory, divided the 40 section, and installed 6 nodes as a reference node. We obtained the log-normal path loss model of wireless channels, RSSI converted into the distance. The distance values used as the input of LVQ. To learn the LVQ network, we set the target values as section indices. In the experiments, we determined the optimal number of subclass, and confirmed that the success rate of training phase was 96%, test phase was 91%.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09b
• /
• pp.185-188
• /
• 2003

본 논문은 복합적인 상황을 고려한 데이터를 이용하여 얼굴인식을 하는 연구로서, 이산 웨이블렛을 기반으로 하는 다 해상도 분석 방법을 사용하고, 각 해상도로 분해된 영상 중, 스케일 함수에 의해 사영되어진 영역에 LDA(Linear Discriminant Analysis)를 적용하여, 도출된 결과가 기존의 방법들에 비해 더 안정된 성능을 나타냄을 보이고자 한다. 이를 위해, 웨이블렛을 적용하지 않은 이미지에 PCA, LDA, ICA를 이용한 결과와 웨이블렛을 적용한 이미지에 통계적 방법들을 이용한 경우, 그리고 웨이블렛의 각 대역에 통계적인 방법을 적용한 후, 대수적인 합을 하였을 때의 인식율을 학습과 검증의 이미지배열을 바꾸어 가며 총 열여덟회 실험하였다. 이에, 본 논문에서 제안한 방법이 이미지 배열에 영향을 덜 받는 안정적인 성능을 가지고 있음을 확인 할 수 있었다.

• Journal of the Korean Wood Science and Technology
• /
• v.19 no.2
• /
• pp.65-71
• /
• 1991

본 연구는 CCA 처리재의 재건조(再乾燥)시 적용된 건조 스케쥴 (통상(通常) 열기건조(熱氣乾燥)와 고온건조(高溫乾燥) 스케쥴)이 처리재의 휨강도(强度) 성질에 미치는 영향을 고찰하고자 수행되었다. 탄성계수(彈性係數)(MOE), 그리고 비파괴시험(非破壞試驗)에 의해 얻어진 동적(動的) 탄성계수 (Dynamic MOE) 및 대수감쇠율(對數減衰率)(Logarithmic decrement) 은 처리후 재건조에 의해 큰 영향을 받지 않았다. 반면에 적용된 건조 스케쥴에 관계없이 재건조시 심각한 파괴계수(破壞係數)(MOR)의 감소가 파괴계수 분포의 모든 영역에서 초래되었다. 그러나 통상 열기건조(최대 건구온도=$71^{\circ}C$)와 고온건조(건구온도=$110^{\circ}C$) 서로간에는 감소의 정도에 큰 차이가 없었다. 따라서, 처리재의 재건조사 심각한 파괴계수의 감소가 용인(容認)되지 않는다면 CCA로 처리된 Lodgepole pine 각재의 재건조는 미국 연방 임산물 시험장의 Lodgepole pine의 통상 열기건조 스케쥴 (T9-C3) 보다 온화(溫和)한 조건으로 실시되어야 할 것이다.