• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.1
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• pp.34-36
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• 1997

In this paper, we introduce the design method using CAE(Computer Aided Engineering) which is profitable in the compatibility and standardization of the developed product and the reduction of construction time and price to develop and design a machine equipment. Particularly, we select the standard model to design or develop from the large machinery to the super precision one, extract the peculiar characters of the model by the close analysis of the physical and technical part, can predict the previous result of experimental characteristics on objective dimensions through the analogical mathematical analysis, and can induce the design model demanded by user investigating optimal data in advance. We present the analogical algorithms and process method of design factors and restriction factors in the systematization design with computer. Then we analyze step functions for each systematization equipment and induce the process of technical data with actuator model.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.51-60
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• 2024

Aiming at the problem of low contrast and difficult to recognize video images in low-light environment, we propose an adaptive contrast compensation enhancement algorithm based on human visual perception. First of all, the video image characteristic factors in low-light environment are extracted: AL (average luminance), ABWF (average bandwidth factor), and the mathematical model of human visual CRC(contrast resolution compensation) is established according to the difference of the original image's grayscale/chromaticity level, and the proportion of the three primary colors of the true color is compensated by the integral, respectively. Then, when the degree of compensation is lower than the bright vision precisely distinguishable difference, the compensation threshold is set to linearly compensate the bright vision to the full bandwidth. Finally, the automatic optimization model of the compensation ratio coefficient is established by combining the subjective image quality evaluation and the image characteristic factor. The experimental test results show that the video image adaptive enhancement algorithm has good enhancement effect, good real-time performance, can effectively mine the dark vision information, and can be widely used in different scenes.

• The Mathematical Education
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• v.59 no.2
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• pp.101-112
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• 2020

The purpose of this study is to analyze the structures of teacher's discourse according to the pattern of interaction between teachers and students in the understanding mathematical word problem. The structures of teacher's discourse could be conceptualized as a process in which the teacher starts, develops and organizes the discourse based on prior research. For this purpose, the fourth class(example, a problem of the same type as the example, formative assessment, and final assessment) was extracted from one semester of experienced teachers who have been practicing teaching methods to facilitate student participation for many years. A methodology used to develop a theory based on data collected through classroom observations. Because the purpose of the study is to identify the structures of teacher's discourse to help the problem understanding, observe the teacher's discourse and collect data based on student engagement. Results show that the structure of teacher's discourse, which consults on important aspects of interaction between teachers-students and creates mathematical meanings, helped students understand the mathematics word problem by promoting their engagement in class. Based on the structures of teacher's discourse to understand problems based on the interaction patterns between teachers and students, it can be said that teachers provided specific methodologies on how to communicate with students in order to understand problems in the future.

• Korean Journal of Cognitive Science
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• v.28 no.3
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• pp.149-171
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• 2017

In this research, based on the fact that spatial ability is important for the achievement in the STEM fields, and technological innovation, Purdue Spatial Visualization Test-Rotation has been used to investigate engineering freshmen's spatial ability and gender differences. Students who have taken advanced mathematics courses in high school(those who have taken type B math test in Korean SAT test) and students with general math courses(those who have taken type A in Korean SAT-Math test) are included in this study to find out the relationship between mathematics achievement and spatial ability. Finding out the strategies taken by students was another aim of this study. This strategic differences between high achievers and lower achievers, male and female students were analyzed from students' self report. Spatial ability test score was highest in the SAT-Math type B male students, decreased in the order of type A male students, type B female students, and lastly type A female students. There was no substantial difference between second and third groups. In each group, male students' average score was 8~10% higher than female students, which affirms 2015's results. The correlation between spatial ability and mathematics achievement was negligible in each group, but male students' math score and spatial ability score were higher than that of female students. This can be interpreted that there is some correlation between these two. Strategic choices can vary in the continuous spectrum with analytic method and holistic method at both ends. From students' self report, using Mann-Witney test, it turned out that there exists strategic differences between male and female students. Male students have a tendency to use holistic strategy more often than female students. I also found that the strategy choice did not vary greatly among all score groups. For the perfect score groups, both female and male students used holistic strategy most frequently. For low achieving groups, there is an evidence that these students overuse one method compared to average or high achieving groups, which turned out to be less effective. Based on these, I suggest that low achieving students need to have more chances to adopt efficient strategies and to practice challenging problems to improve their spatial abilities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.1-10
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• 2012

Recent spatial information technology has brought innovative improvement in both efficiency and accuracy. Especially, airborne LiDAR system(ALS) is one of the practical sensors to obtain 3D spatial information. Constructing reliable 3D spatial data infrastructure is world wide issue and most of the significant tasks involved with modeling manmade objects. This study aims to create a test data set for developing automatic building modeling methods by simulating point cloud data. The data simulates various roof types including gable, pyramid, dome, and combined polyhedron shapes. In this study, a robust bottom-up method to segment surface patches was proposed for generating building models automatically by determining model key points of the objects. The results show that building roofs composed of the segmented patches could be modeled by appropriate mathematical functions and the model key points. Thus, 3D digitizing man made objects could be automated for digital mapping purpose.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2441-2451
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• 2012

This paper presents the design of a control system for improving performance of a washer fluid heating system (WFHS) which is capable of removing frost, ice, snow and/or other debris from windshield. First, for the WFHS, a modeling process is described, and the extraction of characteristic parameters of the model are made by experimental studies. Design variables that affect on performance of the WFHS are also presented. Secondly, a control system is proposed for improving heating performance of the WFHS, and its performance is verified through experiments. The key feature of the proposed control system is to regulate the current of a booster converter input to the WFHS up to the target value that is set to guarantee heating performance. Target current is calculated by using initial temperature value and employing the mathematical model derived in the paper. Computer simulation and experimental results show that the proposed control system can perform heating operations in a way to satisfy per-determined target performance of the WFHS.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.4
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• pp.86-97
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• 2011

This paper presents a novel algorithm to detect more accurate road lane with image sensor-based color classification and directional edge clustering. With treatment of road region and lane as a recognizable color object, the classification of color cues is processed by an iterative optimization of statistical parameters to each color object. These clustered color objects are taken into considerations as initial kernel information for color object detection and recognition. In order to improve the limitation of object classification using the color cues, the directional edge cures within the estimated region of interest in the lane boundary (ROI-LB) are clustered and combined. The results of color classification and directional edge clustering are optimally integrated to obtain the best detection of road lane. The characteristic of the proposed system is to obtain robust result to all real road environments because of using non-parametric approach based only on information of color and edge clustering without a particular mathematical road and lane model. The experimental results to the various real road environments and imaging conditions are presented to evaluate the effectiveness of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1485-1491
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• 2019

As the type and size of vital signs become extensive at the moment lately, a research is actively progressing to define vital signs as big data and analyze it. We generally use a similar method of processing big data on social network as a way to treat vital signs as big data. Vital Sign Big Data should be extracted as feature data, stored separately, and analyzed with various analytical instruments. In other words, it should ensure interoperability and compatability of data, and the index expression in analytical tools should be concise. For this end, I defined the vital sign as the standard meta-model base of HL7 in this dissertation, and I propose a model for analyzing vital signs using OCL, the OMG's standard mathematical specification language. In addition, the proposed model can be confirmed the applicability by figuring out the consumption of calories using ECG data.

• Journal of Educational Research in Mathematics
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• v.17 no.2
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• pp.127-145
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• 2007

There have been several international lesson studies such as TIMSS Video Study and Learner's Perspective Study. According to the TIMSS Video Study report, within differences found in the lessons in each country is much less than the between differences found in the lessons across countries. This means that each country has its own way of teaching, so called 'national script'. On the contrary, LPS researchers are skeptical about the existence of 'national script' since significant differences are identified within the lessons conducted by the same teacher. The purpose of this study is to analyze the LPS Korean data in terms of class organization and teacher's approach and activities. The categories of class organization are classwork, small group seatwork, and individual seatwork, and the those of teacher's approach and activities are exploratory, directive, summarization, exercises and practice, and assigning homework. Ten lessons were videotaped from two Korean schools respectively, thus altogether twenty lessons were recorded and analyzed. Each lesson shows unique class approach and teacher's approach and activities, however the average of each category in class organization and teacher's approach and activities for the two schools are very similar. This result supports the TIMSS Video Study in the regard that there is a commonality among the lessons within the country, but also confirms the LPS result that it is difficult to assume 'national script'. This study is a preliminary investigation into the LPS Korean data, and the further in-depth interpretation of LPS lessons will be followed.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.507-539
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• 2014

The algebra is an important tool influencing on a mathematics in general. To make good use of the algebra, it is necessary to transfer from a given situation to a proper algebraic representation. But some research in related to algebraic word problems have reported the difficulty changing to a proper algebraic representation. Our study have focused on transformation and elaboration of algebraic representation. We investigated in detail the responses and perceptions of 29 Grade 7 students while transforming to algebraic representation, only concentrating on the literature expression form the problematic situations given. Most of students showed difficulties in transforming both descriptive and geometric problems to algebraic representation. 10% of them responded wrong answers except only a problem. Four of them were interviewed individually to show their thinking and find the factor influencing on a positive elaboration. As results, we could find some characteristics of their thinking including the misconception that regard the problem finding a functional formula because there are the variables x and y in the problematic situation. In addition, we could find the their fixation which student have to set up the equation. Furthermore we could check that making student explain own algebraic representation was able to become the factor influencing on a positive elaboration. From these, we also discussed about several didactical implications.