• Journal of Educational Research in Mathematics
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• v.26 no.4
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• pp.715-730
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• 2016

The purpose of this study is to analyze Descartes's point of view on the mathematical connection of algebra and geometry which help comprehend the traditional frame with a new perspective in order to access to unsolved problems and provide useful pedagogical implications in school mathematics. To achieve the goal, researchers have historically reviewed the fundamental principle and development method's feature of analytic geometry, which stands on the basis of mathematical connection between algebra and geometry. In addition we have considered the significance of geometric solving of equations in terms of analytic geometry by analyzing related preceding researches and modern trends of mathematics education curriculum. These efforts could allow us to have discussed on some opportunities to get insight about mathematical connection of algebra and geometry via geometric approaches for solving equations using the intersection of curves represented on coordinates plane. Furthermore, we could finally provide the method and its pedagogical implications for interpreting geometric approaches to cubic equations utilizing intersection of conic sections in the process of inquiring, solving and reflecting stages.

• School Mathematics
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• v.15 no.2
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• pp.337-352
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• 2013

The purpose of this study is to evaluate the efficacy of teaching methods among elementary school math teachers in terms of student achievement in examinations. Results are based upon data from two elementary schools. The evaluation criteria of fifteen items was modified from Ryang's original MTEBI sixteen items to measure elementary school teachers' math teaching efficacy. The result of this study could be summarized as follows. The students were divided into two groups according to teaching efficiency: higher teaching efficiency and lower teaching efficiency. A comparison of math tests taken by students from these groups demonstrates a significant statistical difference. Students with teachers in the lower efficiency group are likely to under-perform. In consequence, teachers' self-efficiency in math is considered to affect students' learning achievement in mathematics.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.4
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• pp.158-165
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• 2008

LOINC (Logical Observation Identifiers Names and Codes) is a database and universal standard for identifying laboratory and clinical test results that is developed and maintained by Regenstrief Institute. Exchanging laboratory test results is one of the most important area in EHR system and the terminology for laboratory test results has to be standardized. In this paper, we present a pre-preprocessing tool that converts a local database in healthcare organizations to LMOF format LMOF format is required by RELMA and our work helps mapping laboratory test results to LOINC very efficiently Our proposed tool provided user friendly interface and 15% keyword reduction in RELMA search compared to no pre-processing RELMA search.

• Education of Primary School Mathematics
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• v.20 no.2
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• pp.131-142
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• 2017

The purpose of the study is to examine the effect of debate and discussion instruction in mathematics class on mathematics study achievements and attitudes in elementary school. To conduct the research, two classes were verified as the homogeneous groups by a preliminary examination on the fourth grade of J elementary school. After mathematics class, the subjects were conducted the same mathematics study achievement and attitude tests in two groups and were analyzed with descriptive statistics, independent t-test, t-test. Accordingly, debate and discussion instruction in mathematics class is more effective than regular lecture method instruction. debate and discussion instruction in mathematics classes are believed students will participate in the question and understand the mathematical principles and concepts themselves through action to solve the problem and influenced I have a positive attitude towards mathematics.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.1-9
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• 2014

Generally, integral image used for autostereoscopic 3d display is generated for flat lens array, but flat lens array cannot provide a wide range of view for generated integral image because of narrow range of view. To make up for this flat lens array's weak point, curved lens array has been proposed, and due to technical and cost problem, approximate surface lens array composed of several flat lens array is used instead of ideal curved lens array. In this paper, we constructed an approximate surface lens array arranged for $20{\times}8$ square flat lens in 100mm radius sphere, and we could get about twice angle of view compared to flat lens array. Specially, unlike existing researches which manually generate integral image, we propose an OpenCL GPU parallel process algorithm for generating real-time integral image. As a result, we could get 12-20 frame/sec speed about various 3D volume data from $15{\times}15$ approximate surface lens array.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.855-862
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• 2013

A series of 1/5 scale-down reactor flow distribution tests had been conducted to determine the hydraulic characteristics of an APR+ (Advanced Power Reactor Plus), which were used as the input data for an open core thermal margin analysis code. In this study, to examine the applicability of computational fluid dynamics with the porous model to the analysis of APR+ internal flow, simulations were conducted using the commercial multi-purpose computational fluid dynamics software ANSYS CFX V.14. It was concluded that the porous domain approach for some reactor internal structures could adequately predict the flow characteristics inside a reactor in a qualitative manner. If sufficient computational resources are available, the predicted core inlet flow distribution is expected to be more accurate by considering the real geometry of the internal structures, especially upstream of the core inlet.

• Journal of Navigation and Port Research
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• v.37 no.5
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• pp.447-452
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• 2013

Vessel traffic system uses multiple sea surveillance radars as a primary sensor to obtain maritime traffic information like as ship's position, speed, course. The systematic errors such as the range bias and the azimuth bias of the two-dimensional radar system can significantly degrade the accuracy of the radar image and target tracking information. Therefore, the systematic errors of the radar system should be corrected precisely in order to provide the accurate target information in the vessel traffic system. In this paper, it is proposed that the method compensates the range bias and the azimuth bias using AtoN information installed at VTS coverage. The radar measurement residual error model is derived from the standard error model of two-dimensional radar measurements and the position information of AtoN, and then the linear Kalman filter is designed for estimation of the systematic errors of the radar system. The proposed method is validated via Monte-Carlo runs. Also, the convergence characteristics of the designed filter and the accuracy of the systematic error estimates according to the number of AtoN information are analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1171-1180
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• 2010

In wireless sensor networks, reliable event detection is one of the most important research issues. For the reliable event detection, previous works usually assume the events are only individual objects such as tanks and soldiers. Recently, many researches focus on detection of continuous objects such as wild fire and bio-chemical material, but they merely aim at methods to reduce communication costs. Hence, we propose a reliable continuous object detection scheme. However, it might not be trivial. Unlike individual objects that could be referred as a point, a continuous object is shown in a dynamic two-dimensional diagram since it may cover a wide area and it could dynamically alter its own shape according to physical environments, e.g. geographical conditions, wind, and so on. Hence, the continuous object detection reliability can not be estimated by the indicator for individual objects. This paper newly defines the reliability indicator for continuous object detection and proposes an error recovery mechanism relying on the estimation result from the new indicator.

• School Mathematics
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• v.7 no.3
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• pp.269-286
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• 2005

The purpose of this paper is to study the spatial sense that is introduced for the first time in our 7th mathematics curriculum. For this purpose, we first investigated the factors of the spatial sense ability and with this factors, we analyze the errors those was founded in elementary school students' carrying out tasks related to the spatial sense, and the contents of elementary mathematics textbook. From the analysis, we found that the teaching topics in the spatial sense is disagreed with the students' learning level and for each similar topics is cut off into not adjacent grades, connecting these topics to each other and to the other traditional geo-metric topics is not easy. we must consider this findings in the future revision of mathematics curriculum.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.293-300
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• 2013

Road signs are important infrastructures for safe and smooth traffic by providing useful information to drivers. It is necessary to establish road sign DB for managing road signs systematically. To provide such DB, manually detection and recognition from imagery can be done. However, it is time and cost consuming. In this study, we proposed algorithms for automatic recognition of direction information in road sign image. Also we developed algorithm code using OpenCV library, and applied it to road sign image. To automatically detect and recognize direction information, we developed program which is composed of various modules such as image enhancement, image binarization, arrow region extraction, interesting point extraction, and template image matching. As a result, we can confirm the possibility of automatic recognition of direction information in road sign image.