• Title/Summary/Keyword: Mathematic

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Modeling and testing for hydraulic shock regarding a valve-less electro-hydraulic servo steering device for ships

  • Jian, Liao;Lin, He;Rongwu, Xu
    • International Journal of Fluid Machinery and Systems
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    • v.8 no.4
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    • pp.318-326
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    • 2015
  • A valve-less electro-hydraulic servo steering device (short: VSSD) for ships was chosen as a study object, and its mathematic model of hydraulic shock was established on the basis of flow properties and force balance of each component. The influence of system structure parameters, changing rate of motor speed and external load on hydraulic shock strength was simulated by the method of numerical simulation. Experiment was designed to test the hydraulic shock mathematic model of VSSD. Experiment results verified the correctness of the model, and the model provided a correct theoretical method for the calculation and control of hydraulic shock of valve-less electro-hydraulic servo steering device.

Existence and Uniqueness of Solutions for the Semilinear Fuzzy Integrodifferential Equations with Nonlocal Conditions and Forcing Term with Memory

  • Kwun, Young-Chel;Park, Jong-Seo;Kim, Seon-Yu;Park, Jin-Han
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.4
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    • pp.288-292
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    • 2006
  • Many authors have studied several concepts of fuzzy systems. Balasubramaniam and Muralisankar (2004) proved the existence and uniqueness of fuzzy solutions for the semilinear fuzzy integrodifferential equation with nonlocal initial condition. Recently, Park, Park and Kwun (2006) find the sufficient condition of nonlocal controllability for the semilinear fuzzy integrodifferential equation with nonlocal initial condition. In this paper, we study the existence and uniqueness of solutions for the semilinear fuzzy integrodifferential equations with nonlocal condition and forcing term with memory in $E_{N}$ by using the concept of fuzzy number whose values are normal, convex, upper semicontinuous and compactly supported interval in $E_{N}$.

A Mathematical Method for Obstacle-Avoidance and Path-Planning of Robotics

  • Liu, Jiang;Son, Young-Ik;Kim, Kab-Il
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.135-137
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    • 2004
  • In this paper, a new method which is based on mathematics is proposed for the obstacle-avoidance and path-planning (OAPP) of robotics in unknown environment. The robot just knows the start point and the goal point. The robot is represented by a circle(not a point) whose radius is one. After being sensed, the obstacles are represented by some mathematic functions and when avoiding the obstacles, the robot path will be generated autonomously. Along this path, the robot can get the goal point at last. The simulation results show that the proposed method works very well.

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A Fixed Point for Pair of Maps in Intuitionistic Fuzzy Mtric Space

  • Park, Jong-Seo;Kim, Seon-Yu
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.7 no.3
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    • pp.159-164
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    • 2007
  • Park, Park and Kwun[6] is defined the intuitionistic fuzzy metric space in which it is a little revised from Park[5]. According to this paper, Park, Kwun and Park[11] Park and Kwun[10], Park, Park and Kwun[7] are established some fixed point theorems in the intuitionistic fuzzy metric space. Furthermore, Park, Park and Kwun[6] obtained common fixed point theorem in the intuitionistic fuzzy metric space, and also, Park, Park and Kwun[8] proved common fixed points of maps on intuitionistic fuzzy metric spaces. We prove a fixed point for pair of maps with another method from Park, Park and Kwun[7] in intuitionistic fuzzy metric space defined by Park, Park and Kwun[6]. Our research are an extension of Vijayaraju and Marudai's result[14] and generalization of Park, Park and Kwun[7], Park and Kwun[10].

A CHARACTERIZATION OF MCSHANE INTEGRABILITY

  • Park, Chun-Kee
    • Korean Journal of Mathematics
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    • v.4 no.2
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    • pp.89-94
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    • 1996
  • In this paper we prove that for functions from [0,1] into a totally ordered AL-space, Mcshane integrability and absolute Mcshane integrability are equivalent.

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Enhancing Expertise as Math Academic Counselor : Self-study for Math Teacher (수학학습 상담 전문성 신장을 위한 자기연구)

  • Lee, Hee Yeon;Ko, Ho Kyoung
    • Communications of Mathematical Education
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    • v.30 no.2
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    • pp.225-249
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    • 2016
  • This study focuses on enhancing expertise as a study advisor for mathematic teacher in field based on self-study method. By advising math study with students in school, the research was carried out 'process & content of mathematic study method advisement', 'process & content of the self-questioning by the math study adviser', and 'enhancing expertise as a math study counsellor by self-study method'. Overall process has been proceeded through preparation, experiment, result & analysis. Experiment has been done based on consultation modeling for academic high school which ran five times. During consultation, based on analysis & result, researcher has recorded 'self-questioning' report. This report is utilized for 'self-examination' for the researcher along the discussion with counselor for enhancing expertise as a study advisor. By above process, practitioner identifies each own's pros & cons as a mathematic study advisor and strengthens the skill while understanding the subject: student. by 'self-studying' method, advisor enhances its own expertise as a teacher with the achieving student and learns practical knowledge for a math study advisor.

A Study on Learning Style of Level-Differentiated College Mathematics Classes: Focusing on College of Engineering Students (수준별 대학수학 수업의 학습유형 분석에 관한 연구: 공과대학생을 대상으로)

  • Lee, Yoon-Gyeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.373-379
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    • 2016
  • This study examined the level-differentiated mathematic classes to offer basic data for effective college mathematics curriculum. Using the Kolb Learning Style, this study surveyed 213 college engineering students in 6 level-differentiated classes in one university and analyzed the significant consequence. The results showed that the ranking of the Learning Style in a superior mathematic class is Diverger, Accommodator, Assimilator, and Converger. Second, the ranking of the Learning Style in the inferior mathematics class was Accommodator, Diverger, Assimilator, and Converger. Third, for effective class of superior mathematics class, professors need to give sufficient time to analyze mathematics problems by the students themselves. Fourth, for an effective class of inferior mathematic class, professors need to use experimental and diverse teaching method to enhance the students' concentration and learning achievement. Based on this study, professors should develop teaching methods that fit the students' Learning Style and the properties of college mathematics curriculum.

Development of a Tool to Measure Math Anxiety Factors for High School Students and Validation of Validity (고등학생용 수학불안 요인 측정 도구 개발 및 타당도 검증)

  • Kang, Yanggu;Han, Sunyoung
    • Communications of Mathematical Education
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    • v.36 no.2
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    • pp.201-227
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    • 2022
  • The purpose of this study was to develop an instrument measuring mathematics anxiety suitable for Korean High school students. In order to achieve this study purpose, the study was conducted according to the procedure of setting components of mathematics anxiety, developing questions, and verifying validity and reliability. First, in order to set the components of mathematic anxiety, previous studies on mathematic anxiety. Through this, six factors of mathematic anxiety were derived. Next, new questions were developed for each of the six constituent factors. The 122 questions were revised and supplemented through two content validity tests, and the final instrument for mathematics anxiety consisted of 49 questions of 6 factors. Finally, to verify the validity and reliability of the measurement instrument for mathematics anxiety, a survey was conducted on 1,848 students from 16 universities in Seoul and the metropolitan area. Next, a validity analysis was conducted with the 1,645 responses, excluding students who answered that there was no mathematics anxiety. As a result of exploratory factor analysis, 15 out of 49 questions were removed. Six factors were named individual characteristics, pressure on achievement, abstraction in mathematics, teaching and learning style, parental attitudes, and cumulative mathematics subjects. As a result of confirmatory factor analysis, the model fit was found to be appropriate, and the convergence validity and discriminant validity were found to be good.

Mathematics and Society in Koryo and Chosun (고려.조선시대의 수학과 사회)

  • Joung Ji-Ho
    • The Mathematical Education
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    • v.24 no.2
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    • pp.48-73
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    • 1986
  • Though the tradition of Korean mathematics since the ancient time up to the 'Enlightenment Period' in the late 19th century had been under the influence of the Chinese mathematics, it strove to develop its own independent of Chinese. However, the fact that it couldn't succeed to form the independent Korean mathematics in spite of many chances under the reign of Kings Sejong, Youngjo, and Joungjo was mainly due to the use of Chinese characters by Koreans. Han-gul (Korean characters) invented by King Sejong had not been used widely as it was called and despised Un-mun and Koreans still used Chinese characters as the only 'true letters' (Jin-suh). The correlation between characters and culture was such that, if Koreans used Han-gul as their official letters, we may have different picture of Korean mathematics. It is quite interesting to note that the mathematics in the 'Enlightenment Period' changed rather smoothly into the Western mathematics at the time when Han-gul was used officially with Chinese characters. In Koryo, the mathematics existed only as a part of the Confucian refinement, not as the object of sincere study. The mathematics in Koryo inherited that of the Unified Shilla without any remarkable development of its own, and the mathematicians were the Inner Officials isolated from the outside world who maintained their positions as specialists amid the turbulence of political changes. They formed a kind of Guild, their posts becoming patrimony. The mathematics in Koryo significant in that they paved the way for that of Chosun through a few books of mathematics such as 'Sanhak-Kyemong', 'Yanghwi-Sanpup' and 'Sangmyung-Sanpup'. King Sejong was quite phenomenal in his policy of promotion of mathematics. King himself was deeply interested in the study, createing an atmosphere in which all the high ranking officials and scholars highly valued mathematics. The sudden development of mathematic culture was mainly due to the personality and capacity of king who took anyone with the mathematic talent into government service regardless of his birth and against the strong opposition of the conservative officials. However, King's view of mathematics never resulted in the true development of mathematics perse and he used it only as an official technique in the tradition way. Korean mathematics in King Sejong's reign was based upon both the natural philosophy in China and the unique geo-political reality of Korean peninsula. The reason why the mathematic culture failed to develop continually against those social background was that the mathematicians were not allowed to play the vital role in that culture, they being only the instrument for the personality or politics of the king. While the learned scholar class sometimes played the important role for the development of the mathematic culture, they often as not became an adamant barrier to it. As the society in Chosun needed the function of mathematics acutely, the mathematicians formed the settled class called Jung-in (Middle-Man). Jung-in was a unique class in Chosun and we can't find its equivalent in China or Japan. These Jung-in mathematician officials lacked tendency to publish their study, since their society was strictly exclusive and their knowledge was very limited. Though they were relatively low class, these mathematicians played very important role in Chosun society. In 'Sil-Hak (the Practical Learning) period' which began in the late 16th century, especially in the reigns of Kings Youngjo and Jungjo, which was called the Renaissance of Chosun, the ambitious policy for the development of science and technology called for. the rapid increase of he number of such technocrats as mathematics, astronomy and medicine. Amid these social changes, the Jung-in mathematicians inevitably became quite ambitious and proud. They tried to explore deeply into mathematics perse beyond the narrow limit of knowledge required for their office. Thus, in this period the mathematics developed rapidly, undergoing very important changes. The characteristic features of the mathematics in this period were: Jung-in mathematicians' active study an publication, the mathematic studies by the renowned scholars of Sil-Hak, joint works by these two classes, their approach to the Western mathematics and their effort to develop Korean mathematics. Toward the 'Enlightenment Period' in the late 19th century, the Western mathematics experienced great difficulty to take its roots in the Peninsula which had been under the strong influence of Confucian ideology and traditional Korean mathematic system. However, with King Kojong's ordinance in 1895, the traditional Korean mathematics influenced by Chinese disappeared from the history of Korean mathematics, as the school system was hanged into the Western style and the Western mathematics was adopted as the only mathematics to be taught at the Schools of various levels. Thus the 'Enlightenment Period' is the period in which Korean mathematics shifted from Chinese into European.

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