• Title/Summary/Keyword: Smooth and non-smooth function

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Optimization of Economic Load Dispatch Problem Using Linearly Approximated Smooth Fuel Cost Function (선형 근사 평활 발전 비용함수를 이용한 경제급전 문제의 최적화)

  • Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.3
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    • pp.191-198
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    • 2014
  • This paper proposes a simple linear function approximation method to solve an economic load dispatch problem with complex non-smooth generating cost function. This algorithm approximates a non-smooth power cost function to a linear approximate function and subsequently shuts down a generator with the highest operating cost and reduces the power of generator with more generating cost in order to balance the generating power and demands. When applied to the most prevalent benchmark economic load dispatch cases, the proposed algorithm is found to dramatically reduce the power cost than does heuristic algorithm. Moreover, it has successfully obtained results similar to those obtained through a quadratic approximate function method.

A PETROV-GALERKIN METHOD FOR A SINGULARLY PERTURBED ORDINARY DIFFERENTIAL EQUATION WITH NON-SMOOTH DATA

  • Zheng T.;Liu F.
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.317-329
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    • 2006
  • In this paper, a singularly perturbed ordinary differential equation with non-smooth data is considered. The numerical method is generated by means of a Petrov-Galerkin finite element method with the piecewise-exponential test function and the piecewise-linear trial function. At the discontinuous point of the coefficient, a special technique is used. The method is shown to be first-order accurate and singular perturbation parameter uniform convergence. Finally, numerical results are presented, which are in agreement with theoretical results.

Smoothly Connected Path Generation and Time-Scheduling Method for Industrial Robot Applications (산업용로봇 작업을 위한 유연한 연결경로 생성과 시간계획)

  • Lee Won-Il;Ryu Seok-Chang;Cheong Joo-No
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.7
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    • pp.671-678
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    • 2006
  • This article proposes a smooth path generation and time scheduling method for general tasks defined by non-smooth path segments in industrial robotic applications. This method utilizes a simple 3rd order polynomial function for smooth interpolation between non-smooth path segments, so that entire task can effectively maintain constant line speed of operation. A predictor-corrector type numerical mapping technique, which correlates time based speed profile to the smoothed path in Cartesian space, is also provided. Finally simulation results show the feasibility of the proposed algorithm.

AN INEQUALITY OF SUBHARMONIC FUNCTIONS

  • Choi, Chang-Sun
    • Journal of the Korean Mathematical Society
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    • v.34 no.3
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    • pp.543-551
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    • 1997
  • We prove a norm inequality of the form $\left\$\mid$ \upsilon \right\$\mid$ \leq (r - 1) \left\$\mid$ u \right\$\mid$_p, 1 < p < \infty$, between a non-negative subharmonic function u and a smooth function $\upsilon$ satisfying $$\mid$\upsilon(0)$\mid$ \leq u(0), $\mid$\nabla\upsilon$\mid$ \leq \nabla u$\mid$$ and $\mid$\Delta\upsilon$\mid$ \leq \alpha\Delta u$, where $\alpha$ is a constant with $0 \leq \alpha \leq 1$. This inequality extends Burkholder's inequality where $\alpha = 1$.

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SOME MODELS FOR PROGRESSIVE TAXATION

  • Kim, Hong-Jong
    • Communications of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.823-831
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    • 2018
  • We define progressive tax rate functions, study their properties, and describe some smooth models. The key requirement, defining the progressive nature of the taxation model, is that the progressive tax rate functions should have infinite contact with the zero function at the origin, in order to care the poor. In constructing a wide array of such functions, assisting functions are introduced.

Development of a 3-D CFD Program for Computing Two-Phase Flows with a Level Set Method (Level Set 상경계면 추적법을 적용한 3차원 CFD 프로그램의 개발)

  • Son G.;Hur N.
    • Journal of computational fluids engineering
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    • v.9 no.3
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    • pp.73-80
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    • 2004
  • A LS(Level Set) formulation is developed for computing two-phase flows on non- orthogonal meshes. Compared with the VOF(Volume-of-Fluid) method based on a non-smooth volume-fraction function, the LS method can calculate an interfacial curvature more accurately by using a smooth distance function. Also, it is quite straightforward to implement for 3-D irregular meshes compared with the VOF method requiring much more complicated geometric calculations. The LS formulation is implemented into a general purpose program for 3-D flows and verified through several test problems.

Estimation of smooth monotone frontier function under stochastic frontier model (확률프런티어 모형하에서 단조증가하는 매끄러운 프런티어 함수 추정)

  • Yoon, Danbi;Noh, Hohsuk
    • The Korean Journal of Applied Statistics
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    • v.30 no.5
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    • pp.665-679
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    • 2017
  • When measuring productive efficiency, often it is necessary to have knowledge of the production frontier function that shows the maximum possible output of production units as a function of inputs. Canonical parametric forms of the frontier function were initially considered under the framework of stochastic frontier model; however, several additional nonparametric methods have been developed over the last decade. Efforts have been recently made to impose shape constraints such as monotonicity and concavity on the non-parametric estimation of the frontier function; however, most existing methods along that direction suffer from unnecessary non-smooth points of the frontier function. In this paper, we propose methods to estimate the smooth frontier function with monotonicity for stochastic frontier models and investigate the effect of imposing a monotonicity constraint into the estimation of the frontier function and the finite dimensional parameters of the model. Simulation studies suggest that imposing the constraint provide better performance to estimate the frontier function, especially when the sample size is small or moderate. However, no apparent gain was observed concerning the estimation of the parameters of the error distribution regardless of sample size.

NUMERICAL ANALYSIS OF MULTIPHASE FLOW BY NUFLEX (NUFLEX의 다상유동 해석)

  • Son, Gi-Hun;Suh, Young-Ho;YU, Tae-Jin;Hur, Nahm-Keon
    • 한국전산유체공학회:학술대회논문집
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    • 2007.04a
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    • pp.95-98
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    • 2007
  • A general purpose program NUFLEX has been extended for two-phase flows with topologically complex interface and cavitation flows with liquid-vapor phase change caused by large pressure drop. In analysis of two-phase flow, the phase interfaces are tracked by employing a LS(Level Set) method. Compared with the VOF(Volume-of-Fluid} method based on a non-smooth volume-fraction function, the LS method can calculate an interfacial curvature more accurately by using a smooth distance function. Also, it is quite straightforward to implement for 3-D irregular meshes compared with the VOF method requiring much more complicated geometric calculations. Also, the cavitation process is computed by including the effects of evaporation and condensation for bubble formation and collapse as well as turbulence in flows. The volume-faction and continuity equations are adapted for cavitation models with phase change. The LS and cavitation formulation are implemented into a general purpose program for 3-D flows and verified through several test problems.

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ERROR BOUNDS FOR NONLINEAR MIXED VARIATIONAL-HEMIVARIATIONAL INEQUALITY PROBLEMS

  • A. A. H. Ahmadini;Salahuddin;J. K. Kim
    • Nonlinear Functional Analysis and Applications
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    • v.29 no.1
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    • pp.15-33
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    • 2024
  • In this article, we considered a class of nonlinear variational hemivariational inequality problems and investigated a gap function and regularized gap function for the problems. We discussed the global error bounds for such inequalities in terms of gap function and regularized gap functions by utilizing the Clarke generalized gradient, relaxed monotonicity, and relaxed Lipschitz continuous mappings. Finally, as applications, we addressed an application to non-stationary non-smooth semi-permeability problems.