• Title/Summary/Keyword: concave functions

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Recognition and positioning of occuluded objects using polygon segments (다각형 세그먼트를 이용한 겹쳐진 물체의 인식 및 위치 추정)

  • 정종면;문영식
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.5
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    • pp.73-82
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    • 1996
  • In this paper, an efficient algorithm for recognizing and positioning occuluded objects in a two-dimensional plane is presented. Model objects and unknown input image are approximated by polygonal boundaries, which are compactly represented by shape functions of the polygons. The input image is partitioned into measningful segments whose end points are at the locations of possible occlusion - i.e. at concave vertices. Each segment is matched against known model objects by calculating a matching measure, which is defined as the minimum euclidean distance between the shape functions. An O(mm(n+m) algorithm for computing the measure is presentd, where n and m are the number of veritces for a model and an unknown object, respectively. Match results from aprtial segments are combined based on mutual compatibility, then are verified using distance transformation and translation vector to produce the final recognition. The proposed algorithm is invariant under translation and rotation of objects, which has been shown by experimental results.

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A New Approach to Solve the Rate Control Problem in Wired-cum-Wireless Networks

  • Loi Le Cong;Hwang Won-Joo
    • Journal of Korea Multimedia Society
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    • v.9 no.12
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    • pp.1636-1648
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    • 2006
  • In this paper, we propose a new optimization approach to the rate control problem in a wired-cum-wireless network. A primal-dual interior-point(PDIP) algorithm is used to find the solution of the rate optimization problem. We show a comparison between the dual-based(DB) algorithm and PDIP algorithm for solving the rate control problem in the wired-cum-wireless network. The PDIP algorithm performs much better than the DB algorithm. The PDIP can be considered as an attractive method to solve the rate control problem in network. We also present a numerical example and simulation to illustrate our conclusions.

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Some characterizations of a mapping defined by interval-valued Choquet integrals

  • Jang, Lee-Chae;Kim, Hyun-Mee
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.7 no.1
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    • pp.66-70
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    • 2007
  • Note that Choquet integral is a generalized concept of Lebesgue integral, because two definitions of Choquet integral and Lebesgue integral are equal if a fuzzy measure is a classical measure. In this paper, we consider interval-valued Choquet integrals with respect to fuzzy measures(see [4,5,6,7]). Using these Choquet integrals, we define a mappings on the classes of Choquet integrable functions and give an example of a mapping defined by interval-valued Choquet integrals. And we will investigate some relations between m-convex mappings ${\phi}$ on the class of Choquet integrable functions and m-convex mappings $T_{\phi}$, defined by the class of closed set-valued Choquet integrals with respect to fuzzy measures.

MONOTONICITY AND LOGARITHMIC CONVEXITY OF THREE FUNCTIONS INVOLVING EXPONENTIAL FUNCTION

  • Guo, Bai-Ni;Liu, Ai-Qi;Qi, Feng
    • The Pure and Applied Mathematics
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    • v.15 no.4
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    • pp.387-392
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    • 2008
  • In this note, an alternative proof and extensions are provided for the following conclusions in [6, Theorem 1 and Theorem 3]: The functions $\frac1{x^2}-\frac{e^{-x}}{(1-e^{-x})^2}\;and\;\frac1{t}-\frac1{e^t-1}$ are decreasing in (0, ${\infty}$) and the function $\frac{t}{e^{at}-e^{(a-1)t}}$ for a $a{\in}\mathbb{R}\;and\;t\;{\in}\;(0,\;{\infty})$ is logarithmically concave.

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Phase-shifting diffraction grating interferometer for testing concave mirrors (오목 거울 측정용 위상천이 회절격자 간섭계)

  • 황태준;김승우
    • Korean Journal of Optics and Photonics
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    • v.14 no.4
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    • pp.392-398
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    • 2003
  • We present a novel concept of a phase-shifting diffraction-grating interferometer, which is intended for the optical testing of concave mirrors with high precision. The interferometer is configured with a single reflective diffraction grating, which performs multiple functions of beam splitting, beam recombination, and phase shifting. The reference and test wave fronts are generated by means of reflective diffraction at the focal plane of a microscope objective with large numerical aperture, which allows testing fast mirrors with low f-numbers. The fiber-optic confocal design is adopted for the microscope objective to focus a converging beam on the diffractive grating, which greatly reduces the alignment error between the focusing optics and the diffraction grating. Translating the grating provides phase shifting, which allows measurement of the figure errors of the test mirror to nanometer accuracy.

A Dynamic Remanufacturing Planning Problem with Discount Purchasing Options (할인구매옵션을 고려한 동적 재생산계획문제)

  • Lee, Woon-Seek
    • Journal of the Korean Operations Research and Management Science Society
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    • v.34 no.3
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    • pp.71-84
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    • 2009
  • This paper considers a remanufacturing and purchasing planning problem, in which either used products(or wastes) are remanufactured or remanufactured products(or final products) are purchased to satisfy dynamic demands of remanufactured products over a discrete and finite time horizon. Also, as remanufactured products are purchased more than or equal to a special quantity Q, a discount price policy is applied. The problem assumes that the related cost(remanufacturing and inventory holding costs of used products, and the purchasing and inventory holding costs of remanufactured products) functions are concave and backlogging is not allowed. The objective of this paper is to determine the optimal remanufacturing and purchasing policy that minimizes the total cost to satisfy dynamic demands of remanufactured products. This paper characterizes the properties of the optimal policy and then, based on these properties, presents a dynamic programming algorithm to find the optimal policy. Also, a network-based procedure is proposed for the case of a large quantity of low cost used products. A numerical example is then presented to demonstrate the procedure of the proposed algorithm.

LIMITING PROPERTIES FOR A MARKOV PROCESS GENERATED BY NONDECREASING CONCAVE FUNCTIONS ON $R_{n}^{+}$

  • Lee, Oe-Sook
    • Communications of the Korean Mathematical Society
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    • v.9 no.3
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    • pp.701-710
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    • 1994
  • Suppose ${X_n}$ is a Markov process taking values in some arbitrary space $(S, \varphi)$ with n-stemp transition probability $$ P^{(n)}(x, B) = Prob(X_n \in B$\mid$X_0 = x), x \in X, B \in \varphi.$$ We shall call a Markov process with transition probabilities $P{(n)}(x, B)$ $\phi$-irreducible for some non-trivial $\sigma$-finite measure $\phi$ on $\varphi$ if whenever $\phi(B) > 0$, $$ \sum^{\infty}_{n=1}{2^{-n}P^{(n)}}(x, B) > 0, for every x \in S.$$ A non-trivial $\sigma$-finite measure $\pi$ on $\varphi$ is called invariant for ${X_n}$ if $$ \int{P(x, B)\pi(dx) = \pi(B)}, B \in \varphi $$.

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A Two-location Production and Inventory Model for Production Facilities with Capacity Reductions (생산용량감소가 허용되는 2개 생산시설의 생산 및 재고모형)

  • Gang Byeong-Su;Ha Seok-Tae
    • Journal of the military operations research society of Korea
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    • v.18 no.2
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    • pp.167-180
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    • 1992
  • This paper considers a two-location production and inventory model for a single product which can be produced and demanded at each of two locations. Demands during a finite number of discrete time periods are known and must be satisfied by production, inventory or transshipment. We consider the change of production capacity. The costs to be incurred are restricted to production, inventory and transshipment costs, and all cost functions we assumed to be concave. The objective is to minimize the total cost of production, inventory and transshipment. The model is formulated as a shortest path problem for an acyclic network from which properties associated with optimal solutions are derived. Using these properties. we develop a dynamic programming algorithm that finds optimal solutions for problems.

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A Capacity Expansion Planning Model for Single-Facility with Two Distinct Capacity Type (두개의 차별적인 용량형태를 갖는 단일설비에 대한 용량 확장계획 모형)

  • Chang, Suk-Hwa
    • Journal of Korean Institute of Industrial Engineers
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    • v.16 no.1
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    • pp.51-58
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    • 1990
  • A deterministic capacity expansion planning model for a two-capacity type facility is analyzed to determine the sizes to be expanded in each period so as to supply the known demands for two distinct capacity type(product) on time and to minimize the total cost incurred over a finite planning horizon of T periods. The model assumes that capacity unit of the facility simultaneously serves a prespecified number of demand units of each capacity type, that capacity type 1 can be used to supply demands for capacity type 2, but that capacity type 2 can't be used to supply demands for capacity type 1. Capacity expansion and excess capacity holding cost functions considered are nondecreasing and concave. The structure of an optimal solution is characterized and then used in developing an efficient dynamic programming algorithm that finds optimal capacity planning policy.

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