• Education of Primary School Mathematics
• /
• v.23 no.1
• /
• pp.45-61
• /
• 2020

The concept of equality is given as a way of reading the equal sign without dealing it explicitly in elementary school mathematics. The meaning of the equal sign can be largely categorized as operational and relational views. However, most elementary school students understand the equal sign as an operational symbol for just writing the required answers. It is essential for them to understand a relational concept of the equal sign because algebraic thinking in middle school mathematics is based on students' understanding of a relational view of the equal sign. Recently, the relational meaning of the equal sign is emphasized in arithmetic. Hence it is necessary for elementary school students to have some activities so that they experience a relational meaning of the equal sign. In this study, we investigate the meaning of the equal sign and contexts of the equal sign in elementary school mathematics to discuss explicit ways to emphasize the concept of equality and relational views of the equal sign.

• Journal of the Ergonomics Society of Korea
• /
• v.34 no.5
• /
• pp.411-426
• /
• 2015

Objective: The goal of this thesis is to design the interaction structure and framework of system to recognize sign language. Background: The sign language of meaningful individual gestures is combined to construct a sentence, so it is difficult to interpret and recognize the meaning of hand gesture for system, because of the sequence of continuous gestures. This being so, in order to interpret the meaning of individual gesture correctly, the interaction structure and framework are needed so that they can segment the indication of individual gesture. Method: We analyze 700 sign language words to structuralize the sign language gesture interaction. First of all, we analyze the transformational patterns of the hand gesture. Second, we analyze the movement of the transformational patterns of the hand gesture. Third, we analyze the type of other gestures except hands. Based on this, we design a framework for sign language interaction. Results: We elicited 8 patterns of hand gesture on the basis of the fact on whether the gesture has a change from starting point to ending point. And then, we analyzed the hand movement based on 3 elements: patterns of movement, direction, and whether hand movement is repeating or not. Moreover, we defined 11 movements of other gestures except hands and classified 8 types of interaction. The framework for sign language interaction, which was designed based on this mentioned above, applies to more than 700 individual gestures of the sign language, and can be classified as an individual gesture in spite of situation which has continuous gestures. Conclusion: This study has structuralized in 3 aspects defined to analyze the transformational patterns of the starting point and the ending point of hand shape, hand movement, and other gestures except hands for sign language interaction. Based on this, we designed the framework that can recognize the individual gestures and interpret the meaning more accurately, when meaningful individual gesture is input sequence of continuous gestures. Application: When we develop the system of sign language recognition, we can apply interaction framework to it. Structuralized gesture can be used for using database of sign language, inventing an automatic recognition system, and studying on the action gestures in other areas.

• Journal of the Ergonomics Society of Korea
• /
• v.34 no.1
• /
• pp.75-83
• /
• 2015

Objective: The aim of this study is to suggest the standard of the direction sign on the pendant switch of overhead cranes which can reduce human errors in control. Background: A great number of crane accidents occur in industries. One of the major causes of the accidents is the mistake in the control of cranes by confusing the orientation of crane movements. Nevertheless, three different direction sign styles, 'East, West, South, North (EWSN)', 'Forward, Backward, Left, Right (FBLR)', and arrows for four directions are used without standardization. Method: An overhead crane simulator was installed for a laboratory experiment. It could move along six directions by the control of a pendant switch. 90 participants were evenly assigned to the three different conditions of direction sign styles. The participants were asked to control the pendant switch according to the continuously appearing 16 direction signs on a monitor ahead. The participants were allowed to refer an orientation sign board on the ceiling representing correct movement directions of the overhead crane simulator. Results: The direction sign style, 'EWSN', showed statistically significant better performance in task completion time and number of errors than the other sign styles. The direction sign style, 'EWSN', adopting the cardinal direction system, made the participants clear in direction controls after customizing to the crane movements. However, the direction sign styles, 'FBLR' and the arrows adopting the relative direction system made conflicts in direction controls due to the egocentric view of human. Conclusion: The direction sign style, 'EWSN', is the most appropriate for the standardization of the direction sign on the pendant switch of overhead cranes. Application: The results of this study can be applied to the standardization of direction sign in the legal notification on the safety certifications of crane manufacturing.

• Research in Mathematical Education
• /
• v.18 no.4
• /
• pp.237-256
• /
• 2014

This paper reports findings from a written assessment which was designed to investigate Chinese primary school students' understanding of the equal sign and equation structure. The investigation included a sample of 110 Grade 3, 112 Grade 4, and 110 Grade 5 students from four schools in China. Significant differences were identified among the three grades and no gender differences were found. The majority of Grades 3 and 4 students were found to view the equal sign as a place indicator meaning "write the answer here" or "do something like computation", that is, holding an operational view of the equal sign. A part of Grade 5 students were found to be able to interpret the equal sign as meaning "the same as", that is, holding a relational view of the equal sign. In addition, even though it was difficult for Grade 3 students to recognize the underlying structure in arithmetic equation, quite a number of Grades 4 and 5 students were able to recognize the underlying structure on some tasks. Findings in this study suggest that Chinese primary school students demonstrate a relational understanding of the equal sign and a strong structural sense of equations in an earlier grade. Moreover, what found in the study support the argument that students' understanding of the equal sign is influenced by the context in which the equal sign is presented.

• Smart Media Journal
• /
• v.1 no.3
• /
• pp.8-14
• /
• 2012

In this paper, we develope the smart phone App. contents of 3D sign language to widen the opportunity of the korean sign language education for the hearing-impaired and normal people. Especially, we propose the sign language conversion algorithm that automatically transform the structure of Korean phrases to the structure of the sign language. Also, we implement the 3D sign language animation DB using motion capture system and data glove for acquiring the natural motions. Finally, UNITY 3D engine is used for the realtime 3D rendering of sign language motion. We are distributing the proposed App. with 3D sign language DB of 1,300 words to the iPhone App. store and Android App. store.

• The Mathematical Education
• /
• v.55 no.1
• /
• pp.1-19
• /
• 2016

Given the importance of understanding the equal sign in developing early algebraic thinking, this paper investigated how a total of 695 students in grades 2~6 understood the equal sign. The students completed a questionnaire with three types of items (equation structure, equal sign definition, and open equation solving) based on the construct map by four different levels of understanding the equal sign. The questionnaire was analyzed by Rasch model. The results showed that about 80% of the students were at least Level 3 which means a basic relational understanding of the equal sign. However, the success rates varied across grades and it was noticeable that about 70% of the second graders remained at Level 1 or 2 which maintains an operational understanding of the equal sign. The results of item types demonstrated that item difficulty for the advanced relational thinking was the highest and this is the same even for the Level 4 students. This paper is expected to investigate elementary school students' understanding of the equal sign and provide implications of how to deal with the equal sign in the elementary school.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.2
• /
• pp.130-135
• /
• 2002

A new Sign algorithm which has improved convergence speed is presented. The data-recycling technique, whose coefficients are multiply adapted in a symbol time period by recycling the received data, is applied to Sign algorithm which has few multiplications. Sign algorithm has very few multiplications and is the most easily implemented, but it gives small rate of convergence relative to others. The proposed algorithm combines the advatage of Sign algorithm, few multiplications, and the virtue of Data-Recycling LMS algorithm, simplicity and fast convergence. The results of computer simulation show that the proposed algorithm has 2 times faster convergence rate than that of LMS algorithm. Comparing to Data-Recycling LMS algorithm, in similar convergence conditions, it requires half fewer multiplications.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.29 no.11
• /
• pp.1410-1420
• /
• 2005

The purpose of this study was to analyze characteristics of effective expression on T-shirts pattern by peirce's semiotic theory. The methods of this study was to analyze 721 T-shirts patterns in designer's collection from 2000 to 2004. The results of this study were as follows: First of all, iconic expression showed high frequency after 2000. Characteristics of effective expression were as follows: In geometric expression, repetition was presented as a symbolic sign by regular proportion and rule of dot, line, plane, irregularity, mixture of irregular dot, line, plane. Mixed expression was presented as a iconic and symbolic sign by collage, mixture of dot, line, plane, icon and letter. In iconic expression, simplification of iconic sigrl was presented as a iconic sign by simplification of form, color, texture, realistic expression using digital as a iconic sign, and symbolic face, body as a symbolic sign. Pop art's expression was presented as a iconic sign by a cartoon and commercial character and illusion was presented as a iconic sign. In letter's expression, brand logo was presented as a symbolic sign by transformation of letter's design, a symbolic sign of numeral by transformation of size, thickness, form, color. Symbolic message phrase was presented by slogan, fashion trend, brand image, descriptive indication message as a index sign by using icon or singleness. In conclusion, characteristics of effective expression on T-shirts pattern will present not only the theoretical foundation to raise the value added, but also the information about beauty sense of times, political and social value.

• International Journal of Highway Engineering
• /
• v.15 no.5
• /
• pp.187-193
• /
• 2013

PURPOSES : This research is to analyze the influence in terms of misreading rate and legibility time for drivers when condensation occurs on the road signs. METHODS : In this research, the dew occurred road signs provided to drivers to measure legibility time and misreading rate to compare with normal road sign. In order to identify the difference of legibility time between normal road sign and dew occurred road sign, the T-test and ANOVA test were used. And the vision system was used to recognize the region of dew occurrence on the road sign, then the brightness of dew occurrence region on the road sign was changed to check the misreading rate of drivers according to the change rate of brightness. RESULTS : The legibility times were measured 2.65s for normal road sign and 4.08s for dew occurrence road sign and misreading rates were measured 2.8% for normal road sign, 21.7% for dew occurrence road sign.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.18 no.1
• /
• pp.103-114
• /
• 2008

Single Sign-On is an authentication scheme that enables a user to authenticate once and then to access to the resources of multiple software systems without re-authentication. As web services are being integrated into a single groupware, more web sites are adopting for user convenience. However, these Single Sign-On services are very dependent upon the cookies and thus, simple eavesdropping enables attackers to hiject the user's session. Even worse, the attacker who hijacked one session can move to another site through the Single Sign-On. In this paper, we show the vulnerabilities of the top ranked sites regarding this point of view and also propose a way to protect a user's session.