• 제목/요약/키워드: R programming

검색결과 305건 처리시간 0.025초

SOME ALGORITHMS OF THE BEST SIMULTANEOUS APPROXIMATION

  • Rhee, Hyang J.
    • 충청수학회지
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    • 제22권2호
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    • pp.141-148
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    • 2009
  • We consider various algorithms calculating best onesided simultaneous approximations. We assume that X is a compact subset of $\mathbb{R}^{m}$ satisfying $X=\overline{intX}$, S is an n-dimensional subspace of C(X), and $\mu$ is any 'admissible' measure on X. For any l-tuple $f_1,\;{\cdots},\;f_{\ell}$ in C(X), we present various ideas for best approximation to F from S(F). The problem of best (both one and two-sided) approximation is a linear programming problem.

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A note on convexity on linear vector space

  • Hong, Suk-Kang
    • Journal of the Korean Statistical Society
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    • 제1권1호
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    • pp.18-24
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    • 1973
  • Study on convexity has been improved in many statistical fields, such as linear programming, stochastic inverntory problems and decision theory. In proof of main theorem in Section 3, M. Loeve already proved this theorem with the $r$-th absolute moments on page 160 in [1]. Main consideration is given to prove this theorem using convex theorems with the generalized $t$-th mean when some convex properties hold on a real linear vector space $R_N$, which satisfies all properties of finite dimensional Hilbert space. Throughout this paper $\b{x}_j, \b{y}_j$ where $j = 1,2,......,k,.....,N$, denotes the vectors on $R_N$, and $C_N$ also denotes a subspace of $R_N$.

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ITERATIVE METHODS FOR LARGE-SCALE CONVEX QUADRATIC AND CONCAVE PROGRAMS

  • Oh, Se-Young
    • 대한수학회논문집
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    • 제9권3호
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    • pp.753-765
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    • 1994
  • The linearly constrained quadratic programming(QP) considered is : $$ min f(x) = c^T x + \frac{1}{2}x^T Hx $$ $$ (1) subject to A^T x \geq b,$$ where $c,x \in R^n, b \in R^m, H \in R^{n \times n)}$, symmetric, and $A \in R^{n \times n}$. If there are bounds on x, these are included in the matrix $A^T$. The Hessian matrix H may be positive definite or negative semi-difinite. For large problems H and the constraint matrix A are assumed to be sparse.

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R-function을 이용한 형상의 음함수 모델링 및 해석 (Geometric Implicit Function Modeling and Analysis Using R-functions)

  • 신헌주;신동우;김태완
    • 한국CDE학회논문집
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    • 제12권3호
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    • pp.220-232
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    • 2007
  • Current geometric modeling and analysis are commonly based on B-Rep modeling and a finite elements method respectively. Furthermore, it is difficult to represent an object whose material property is heterogeneous using the B-Rep method because the B-Rep is basically used for homogeneous models. In addition, meshes are required to analyze a property of a model when the finite elements method is applied. However, the process of generating meshes from B-Rep is cumbersome and sometimes difficult especially when the model is deformed as time goes by because the topology of deforming meshes are changed. To overcome those problems in modeling and analysis including homogeneous and heterogeneous materials, we suggest a unified modeling and analysis method based on implicit representation of the model using R-function which is suggested by Rvachev. For implicit modeling of an object a distance field is approximated and blended for a complex object. Using the implicit function mesh-free analysis is possible where meshes are not necessary. Generally mesh-free analysis requires heavy computational cost compared to a finite elements method. To improve the computing time of function evaluation, we utilize GPU programming. Finally, we give an example of a simple pipe design problem and show modeling and analysis process using our unified modeling and analysis method.

수직다관절 로봇의 중력보상장치 최적설계 (Optimal Design of Passive Gravity Compensation System for Articulated Robots)

  • 박진균;이재영;김상현;김성락
    • 대한기계학회논문집A
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    • 제36권1호
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    • pp.103-108
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    • 2012
  • 본 논문에서는 수직다관절 로봇에 걸리는 중력 토크를 보상하는데 주로 사용되는 스프링 중력보상장치의 최적설계에 대하여 기술하였다. 스트레스, 좌굴, 피로 조건과 같은 스프링 설계에 대한 다수의 비선형 제약 조건을 반영하면서, 동시에 계산 시간을 줄이기 위하여, SQP(Sequential Quadratic Programming)를 적용하였다. 또한 정수해를 가져야 하는 설계 변수를 반영하기 위하여, Continuous Relaxation 방법을 사용하였다. 시뮬레이션을 통하여 설계된 중력보상 장치가 주요 작업 영역에서 추가의 무게 증가 없이 중력 보상 성능이 효과적으로 높아짐을 입증하였다.

최적 생산/판매 계획을 통한 기업 목표 관리 사례 (Management for Company Objectives with Considerations of Optimal Production/Sales Planning)

  • 정재헌
    • 한국경영과학회지
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    • 제34권2호
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    • pp.77-90
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    • 2009
  • Total profit level Increases if a company increase the cost for achieving R&D related goals of equipment productivity enhancement, production cost saving, or for achieving equipment scale target, sales volume goal. But how much money should be invested to achieve a certain level of profit? We formulated the model to set the optimal goal levels to minimize the investment cost under the constraint that certain level of total profit should be guaranteed. This model derived from a case of P steel company. We found that this should be considered in relation with the production sales planning (known as optimal product mix problem) to guarantee the profit. We suggested a nonlinear programming model, 3 valiant form of the p+roduct mix problem. We can find the optimal Investment level for the R&D related goals or sales volume goal, equipment scale target for the P steel company using the model.

Guided Instruction of Introducing Computational Thinking to Non-Computer Science Education Major Pre-Service Teachers

  • Song, Ki-Sang
    • International journal of advanced smart convergence
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    • 제6권2호
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    • pp.24-33
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    • 2017
  • Since 'teaching coding' or 'programming' classes for computational thinking (CT) education in K-12 are renowned around the world, a pre-service teachers' readiness for integrating CT into their teaching subjects is important due to the fact that CT is considered to be another 'R' from algoRitm for 21st century literacy, in addition to the traditional 3R (Reading, Writhing, and Arithmetic) [2] and CT roles to other disciplines. With this rationale, we designed a guided instruction based CT course for pre-service teachers. We show the effectiveness of the program with respect to the teachers' attitude toward combining CT into their teaching subjects, and mindset changes of learning computing connected with the career development of the teacher themselves. The research focused on the instructional methodology of teaching programing for non-Computer Science Education (CSE) majors who are not familiar with computer science for alleviating the cognitive load of first exposure to programming course under the CT concepts.

Earned Schedule 개념을 활용한 국방 연구개발 사업진도 기법의 일정 관리 및 예측 기능 연구 (Research of Schedule Managing and Forecasting for Project Progress Method in Defense Research & Development using Earned Schedule Concept)

  • 조정호;류상철;임재성
    • 한국군사과학기술학회지
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    • 제22권4호
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    • pp.567-574
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    • 2019
  • Traditional project progress method(PPM) has been used for Korean defense research and development project management for the last 20 years. However, it is difficult to intuitively understand the performance in terms of the project schedule, because the PPM does not provide the function of managing and forecasting project schedule. Therefore, this paper proposes new schedule managing and forecasting function for the PPM using earned schedule management concept. We verify the effectiveness of the proposed functions through several defense projects and prove that it is possible to reinforce the schedule management function of the PPM.

Relational Data Extraction and Transformation: A Study to Enhance Information Systems Performance

  • Forat Falih, Hasan;Muhamad Shahbani Abu, Bakar
    • Journal of information and communication convergence engineering
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    • 제20권4호
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    • pp.265-272
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    • 2022
  • The most effective method to improve information system capabilities is to enable instant access to several relational database sources and transform data with a logical structure into multiple target relational databases. There are numerous data transformation tools available; however, they typically contain fixed procedures that cannot be changed by the user, making it impossible to fulfill the near-real-time data transformation requirements. Furthermore, some tools cannot build object references or alter attribute constraints. There are various situations in which tool changes in data type cause conflicts and difficulties with data quality while transforming between the two systems. The R-programming language was extensively used throughout this study, and several different relational database structures were utilized to complete the proposed study. Experiments showed that the developed study can improve the performance of information systems by interacting with and exchanging data with various relational databases. The study addresses data quality issues, particularly the completeness and integrity dimensions of the data transformation processes.