• Title/Summary/Keyword: 기호계산

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Kinematic Design Sensitivity Analysis of Suspension System Using a Symbolic Computation Method (기호계산 기법을 이용한 현가장치의 기구학적 민감도 해석)

  • 송성재;탁태오
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.6
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    • pp.247-259
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    • 1996
  • Kinematic design sensitivity analysis for vehicle in suspension systems design is performed. Suspension systems are modeled using composite joins to reduce the number of the constraint equations. This allows a semi-analytical approach that is computerized symbolic manipulation before numerical computations and that may compensate for their drawbacks. All the constraint equations including design variables are derived in symbolic equations for sensitivity analysis. By directly differentiating the equations with respect to design variables, sensitivity equations are obtained. Since the proposed method only requires the hard point data, sensitivity analysis is possible in suspension design stage.

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Causal Computationalism and Language Understanding (인과적 계산이론과 언어이해)

  • Kong, Yong-Hyun
    • Annual Conference on Human and Language Technology
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    • 1992.10a
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    • pp.629-636
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    • 1992
  • 컴퓨터의 언어이해 가능성을 반박하는 주된 근거는 형식적 기호들을 처리하는 프로그램이 의미론을 다룰 수 없다는 것이다. 그러나 인과적 계산이론에 따르면 컴퓨터 프로그램이 순전히 구문론적인 것은 아니고 컴퓨터 내부의 기호적 표상의 처리과정에서 의미론적인 지시와 해석이 일어난다고 할 수 있다.

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Detection of direction indicators on road surfaces using Inverse Perspective Mapping and NN (역원근 변환과 신경망을 사용한 효율적인 도로노면 방향지시기호 검출 연구)

  • Kim, Jong-Bae
    • Proceedings of the Korea Information Processing Society Conference
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    • 2014.11a
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    • pp.1199-1202
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    • 2014
  • 본 논문은 차량에 설치된 블랙박스 영상으로부터 도로 노면에 표시된 방향지시 기호를 효율적으로 검출하는 방안을 제안한다. 차량 내부에 설치된 블랙박스 영상은 카메라의 원근 효과로 인해 방향지시 기호 영역을 올바르게 검출하지 못하는 문제점이 존재한다. 따라서 제안한 연구에서는 원근 효과를 가진 입력 영상에서 역원근 변환 방법을 통해 원근 효과를 제거한 실세계 좌표로 맵핑한 평면 영상에서 방향지시 기호 영역을 신경망 검출기를 통해 검출한다. 입력 영상에서 역 원근 변환은 높은 계산량으로 인해 실시간 처리가 어려운 점이 존재한다. 이를 보완하기 위해 제안한 방안에서는 입력 영역의 도로노면 방향지시 기호 영역의 특징을 분석하여 도로노면 기호가 포함된 후보 ROI영역을 정의하고 후보 ROI 영역의 Gray 색상에서 역원근 변환을 수행한다. 제안한 방안을 도로노면 방향지시 기호 검출 및 인식 연구에 적용한 결과, 약 87% 이상 비교적 정확히 검출율을 제시하였으며, 다양한 도로 환경에서도 높은 검출율을 제시하였다. 따라서 제안한 방안을 운전자의 안전운전지원시스템에 적용함으로써 보다 정확한 도로정보 제공시스템 적용이 가능함을 알 수 있다.

De Morgan's view on the development of algebra (대수 발달의 단계에 관한 드모르간의 관점 연구)

  • Yu, Mi-Kyung;Kim, Jae-Hong;Kwon, Seok-Il;Park, Sun-Yong;Choi, Ji-Sun;Park, Kyo-Sik
    • Journal for History of Mathematics
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    • v.21 no.4
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    • pp.61-78
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    • 2008
  • In this paper, we discuss about De Morgan's view on the development of algebra according to following distinctions: arithmetic, universal arithmetic, symbolic algebra, significant algebra. De Morgan thought that the differences between arithmetic and universal arithmetic lie in the usage of letters and the immediate performance of computation. In his viewpoint, universal arithmetic is a transitional phase, in which absurd phenomena occur, from arithmetic to algebra and these absurd phenomena call for algebra. The feature of De Morgan's view on the development of algebra is that symbolic calculus which consist of symbol system without symbol's meaning is acquired, then as extended meanings are furnished to symbols, symbolic calculus become logical so significant calculus is developed. For example, Single algebra is developed, as an extended meaning is furnished to a symbol -1, and double algebra is developed, as an extended meaning is furnished to a symbol $\sqrt{-1}$. According to De Morgan, a symbol system is derived from the incompleteness of a prior symbol system.

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Sensitivity Analysis Using a Symbolic Computation Technique and Optimal Design of Suspension Hard Points (기호계산을 이용한 현가장치의 민감도 해석 및 설계점의 최적 설계)

  • Chun, Hung-Ho;Tak, Tae-Oh
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4 s.97
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    • pp.26-36
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    • 1999
  • A general procedure for determining the optimum location of suspension hard points with respect to kinematic design parametes is presented. Suspensions are modeled as connection of rigid bodies by ideal kinematic joints. Constraint equations of the kinematic joints are expressed in terms of the generalized coordinates and hard points. By directly differentiating the constraint equations with respect to the hard points, kinematic sencitivity equations are obtained. In order to cope with algebraic complexity associated with the differentiation process, a symbolic computation technique is used. A performance index is defined in terms of static design parameters such as camber, caster, toe, ect.. Gradient of the performance index can be analytically computed from the kinematic sensitivity equations. Optimization results show the effectiveness and validity of the procedure, which is applicable to any type of suspension if its kinematic configurations are given.

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Analysis of Spatial Mechanism Using Symbolic Computation (기호예산을 이용한 공간기구의 해석)

  • 이동민;윤용산
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1509-1517
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    • 1993
  • The purpose of this study is to develop a program for the automatic derivation of the symbolic equations necessary for the kinematic and dynamic analyses of the spatial mechanism. For this purpose, a symbolic manipulation package called MCSYMA is used. Every symbolic equation is formulated using relative joint coordinate to obtain the numerically efficient system equations. These equations are produced in FORTRAN statements and linked to a FORTRAN program for numerical analysis. Several examples are taken for comparison with the commercial package called DADS which is using Cartesian coordinate approach. Also, this symbolic formulation approach is compared with a conventional numerical approach for an example. The results show that this symbolic approach with relative joint coordinate system is most efficient in computational time among three and is recommended for the derivation of macro elements frequently used.

A Study on Program Development for Static Design Factor of Automotive Suspension System (자동차 현가장치의 정적설계인자 계산을 위한 프로그램 개발에 관한 연구)

  • Kim, Kwang-Suk
    • Journal of the Korea Convergence Society
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    • v.8 no.12
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    • pp.283-289
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    • 2017
  • In this study, a general program has been developed to calculate the static design factor of a vehicle suspension system. The partial derivatives of Jacobians for constraint equations are calculated using the symbolic technique. In the commercial program, finite difference method is used to calculate the Jacobian matrix of Jacobian. But in this study, it is calculated by using the symbol calculation method to precisely consider it. The calculated Jacobian matrix for the system has proved its accuracy through the solution of the numerical example. A simulation was performed for a double wishbone suspension of a 1/4 vehicle. The result can be used to calculate the static design factor of the suspension, and also add a convergence module that can perform virtual tests.

A Study of Development for Korean Phonotactic Probability Calculator (한국어 음소결합확률 계산기 개발연구)

  • Lee, Chan-Jong;Lee, Hyun-Bok;Choi, Hun-Young
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.3
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    • pp.239-244
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    • 2009
  • This paper is to develop the Korean Phonotactic Probability Calculator (KPPC) that anticipates the phonotactic probability in Korean. KPPC calculates the positional segment frequecncy, position-specific biphone frequency and position-specific triphone frequency. And KPPC also calculates the Neighborhood Density that is the number of words that sound similar to a target word. The Phonotactic Calculator that was developed in University of Kansas can be analyzed by the computer-readable phonemic transcription. This can calculate positional frequency and position-specific biphone frequency that were derived from 20,000 dictionary words. But KPPC calculates positional frequency, positional biphone frequency, positional triphone frequency and neighborhood density. KPPC can calculate by korean alphabet or computer-readable phonemic transcription. This KPPC can anticipate high phonotactic probability, low phonotactic probability, high neighborhood density and low neighborhood density.

Study on Sodium Intake and Preference for Salty Taste in College Women (여대생의 Sodium 섭취량과 짠맛의 기호도에 관한 연구)

  • 최봉순;김은정;박영숙
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.1
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    • pp.154-160
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    • 1997
  • College women of 136 in Kyoung-Buk province were studied in order to investigate the quantity of Na intake and preference for salty taste in diet. Also the relation of family's history on hypertention and their Na intake and preference for salty taste were studied. Three type of meal with 9g NaCl, 12g NaCl, 15g NaCl and four type of beef soup with 0.2% NaCl, 0.4% NaCl, 0.6% NaCl, 0.8% NaCl were prepared. The computating value of Na according to the food composition table and the amount of Na by chemical analysis were almost equal. The meal with 12g NaCl was favored 58.8% of the subjects, hence the amount of Na intake per day was thought 13g roughly.50.7% of subjects prefered of beef soup with 0.6% NaCl and those who thought that they eat salty had tendency to like food with high amount of salt. 73 subjects(53.7%) had family's history on hypertention, then 38 subjects (52.9%) among them liked beef soup with 0.4% NaCl 63 subjects(46.3%) didn't have family's history on hypertention, then 44 subjects among thorn liked beef soup with 0.6% NaCl. The subjects with family's history on hypertention liked more salty taste than the subjects with no family.s history on hypertention.

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