L1 norm estimator has been widely used as a robust parameter estimation method for outlier detection. Different algorithms have been applied for L1 norm minimization among which the linear programming problem based on...
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L1 norm estimator has been widely used as a robust parameter estimation method for outlier detection. Different algorithms have been applied for L1 norm minimization among which the linear programming problem based on the simplex method is well known. In the present contribution, in order to solve an L1 norm minimization problem in a linear model, an interior point algorithm is developed which is based on Dikin's method. The method can be considered as an appropriate alternative for the classical simplex method, which is sometimes time-consuming. The proposed method, compared with the simplex method, is thus easier for implementation and faster in performance. Furthermore, a recursive form of the Dikin's method is derived, which resembles the recursive least-squares method. Two simulated numerical examples show that the proposed algorithm gives as accurate results as the simplex method but in considerably less time. When dealing with a large number of observations, this algorithm can thus be used instead of the iteratively reweighted least-squares method and the simplex method.
The objective of this article is to present a step-by-step problem-solving procedure of shape optimization. The procedure is carried out to design an airfoil in the presence of compressible and viscous flows using a c...
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The objective of this article is to present a step-by-step problem-solving procedure of shape optimization. The procedure is carried out to design an airfoil in the presence of compressible and viscous flows using a control theory approach based on measure theory. An optimal shape design (OSD) problem governed by full Navier-Stokes equations is given. Then, a weak variational form is derived from the linearized governing equations. During the procedure, because the measure theory (MT) approach is implemented using fixed geometry versus moving geometry, a proper bijective transformation is introduced. Finally, an approximating linearprogramming (LP) problem of the original shape optimization problem is obtained by means of MT approach that is not iterative and does not need any initial guess to proceed. Illustrative examples are provided to demonstrate efficiency of the proposed procedure.
In a distributed storage system, the storage costs of different storage nodes, in general, can be different. How to store a file in a given set of storage nodes so as to minimize the total storage cost is investigated...
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ISBN:
(纸本)9781424492688
In a distributed storage system, the storage costs of different storage nodes, in general, can be different. How to store a file in a given set of storage nodes so as to minimize the total storage cost is investigated. By analyzing the min-cut constraints of the information flow graph, the feasible region of the storage capacities of the nodes can be determined. The storage cost minimization can then be reduced to a linear programming problem, which can be readily solved. Moreover, the tradeoff between storage cost and repair-bandwidth is established.
A set of linearly constrained permutation matrices are proposed for constructing a class of permutation codes. Making use of linear constraints imposed on the permutation matrices, we can formulate a minimum Euclidian...
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ISBN:
(纸本)9781457705953
A set of linearly constrained permutation matrices are proposed for constructing a class of permutation codes. Making use of linear constraints imposed on the permutation matrices, we can formulate a minimum Euclidian distance decoding problem for the proposed class of permutation codes as a linearprogramming (LP) problem. The main feature of this novel class of permutation codes, called LP decodable permutation codes, is this LP decodability. It is demonstrated that the LP decoding performance of the proposed class of permutation codes is characterized by the vertices of the code polytope of the code. In addition, based on a probabilistic method, several theoretical results for randomly constrained permutation codes are derived.
This paper examines the development of cooperative strategies between countries exporting Liquefied Natural Gas (LNG) and members of the Gas Exporting Countries Forum (GECF). This economic study focuses specifically o...
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This paper examines the development of cooperative strategies between countries exporting Liquefied Natural Gas (LNG) and members of the Gas Exporting Countries Forum (GECF). This economic study focuses specifically on an often-raised scenario: the emergence of a cooperative approach designed with the sole aim of logistic rationalization, and which would not have any effect on LNG prices. We first assess the annual gains that may result from this market-power-free cooperative approach using a simple static transportation model. The numerical results obtained suggest that, in the absence of a gain redistribution policy, this cooperative strategy will probably not be adopted because cooperation would not be a rational move for some exporters. The problem of gain sharing is then formulated using cooperative game theory concepts. Several gain-sharing methods have been studied, including the Shapley value and various nucleolus-inspired concepts. Our results suggest that the choice of a redistribution policy appears relatively restricted. Out of the methods studied, only one - per capita nucleolus - satisfies two key requirements: core belonging and monotonicity (in the aggregate). Lastly, we look at how cooperation may give rise to a coordination cost and try to determine the maximum amount of this cost. In view of the low level of this amount and the relative complexity of the sharing method implemented, we consider that the credibility of a logistic cooperation scenario exempt from market power should be reappraised. (C) 2010 Elsevier B.V. All rights reserved.
The main objective of this research is to identify and analyze the sources of technical inefficiency in turmeric crop farming system in north western region of Tamil Nadu from a sample of 180 turmeric growing farmers....
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The main objective of this research is to identify and analyze the sources of technical inefficiency in turmeric crop farming system in north western region of Tamil Nadu from a sample of 180 turmeric growing farmers. A non-parametric approach, Data Envelopment Analysis (DEA) has been used to estimate Technical Efficiency Scores (TES). Results indicate the presence of technical inefficiency in turmeric farming system. The average technical efficiency score is 79 per cent with the maximum score of 95 per cent and minimum score of 59 per cent. The potential to increase the technical efficiency score of turmeric growing farms is found to be 17 per cent.
This paper deals with a repetitive control problem for the cases where the period of periodic disturbances to be rejected is uncertain but is within known lower and upper bound. A new adaptive repetitive control syste...
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ISBN:
(纸本)9781424453634
This paper deals with a repetitive control problem for the cases where the period of periodic disturbances to be rejected is uncertain but is within known lower and upper bound. A new adaptive repetitive control system with on-line estimation of the period is proposed not only to guarantee stability of the overall system but also both to reject any periodic disturbances with the uncertain period and to reduce sensitivity against any disturbances, for example, non-periodic persistent ones. The design problem is reduced to a simple and feasible l(1) norm minimization problem. The controller can be obtained easily by solving a simple linear programming problem. Simulations show the effectiveness of the proposed controller for rejection of periodic disturbances and sensitivity reduction.
In this article we intend to find the optimal shape of a nozzle respecting to some given target flow fields including viscosity effect. Via an approach based on measure theory which is not an iterative method and need...
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In this article we intend to find the optimal shape of a nozzle respecting to some given target flow fields including viscosity effect. Via an approach based on measure theory which is not an iterative method and need not to any initial guess, each shape optimization problems are solved and consequently each geometry of the nozzle corresponding to prescribed flow fields is determined. Analyzing several case studies make us to confident on the use of the presented approach, because the obtained results give entirely the same as what we expect physically.
In this paper, the uncertainty of the demand in newsvendor problems is characterized by interval probabilities. The characteristics of interval probabilities, the method for estimating interval probabilities from subj...
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ISBN:
(纸本)9781424426294
In this paper, the uncertainty of the demand in newsvendor problems is characterized by interval probabilities. The characteristics of interval probabilities, the method for estimating interval probabilities from subject and decision criteria with interval probabilities are addressed. The newsvendor models under interval probabilities are proposed for obtaining the optimal order quantity.
In recent years, dealing with uncertainty using interval probabilities is receiving considerable attention by researchers. Most of researches related to interval probabilities, such as combination, marginalization, co...
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ISBN:
(纸本)9781424423835
In recent years, dealing with uncertainty using interval probabilities is receiving considerable attention by researchers. Most of researches related to interval probabilities, such as combination, marginalization, condition, Bayesian inferences, assume interval probabilities are known. How to elicit interval probabilities from subject is a basic problem for the applications of interval probability theory and till now a computational challenge. In this research, the approaches for estimating interval probabilities are proposed with the pair-wise comparison of the possible outcomes to know which one is more likely to occur. The first method is LP-based one. The second method is QP-based one. Interval expectation, interval entropy are investigated. The decision criteria under interval probabilities are given.
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