It is a problem to build Inter Satellite Links so that Region Navigation System has optimal performance. Therefore, the article puts forward an algorithm, which synthesizes the time of satellites accessed and the dist...
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ISBN:
(纸本)9783037856932
It is a problem to build Inter Satellite Links so that Region Navigation System has optimal performance. Therefore, the article puts forward an algorithm, which synthesizes the time of satellites accessed and the distance of satellites. And then it carries out a simulation in navigation system to certify the superiority of the algorithm. The experimental result shows that the ISLs can effectively improve the performance of navigation system. And comparing with the traditional Minimum Distance algorithm, the proposed algorithm has the same effect on improving the performance of navigation system and needs fewer times of changing links.
We present a path algorithm for the generalized lasso problem. This problem penalizes the l(1) norm of a matrix D times the coefficient vector, and has a wide range of applications, dictated by the choice of D. Our al...
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We present a path algorithm for the generalized lasso problem. This problem penalizes the l(1) norm of a matrix D times the coefficient vector, and has a wide range of applications, dictated by the choice of D. Our algorithm is based on solving the dual of the generalized lasso, which greatly facilitates computation of the path. For D = I (the usual lasso), we draw a connection between our approach and the well-known LARS algorithm. For an arbitrary D, we derive an unbiased estimate of the degrees of freedom of the generalized lasso fit. This estimate turns out to be quite intuitive in many applications.
The support vector domain description is a one-class classification method that estimates the distributional support of a data set. A flexible closed boundary function is used to separate trustworthy data on the insid...
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The support vector domain description is a one-class classification method that estimates the distributional support of a data set. A flexible closed boundary function is used to separate trustworthy data on the inside from outliers on the outside. A single regularization parameter determines the shape of the boundary and the proportion of observations that are regarded as outliers. Picking an appropriate amount of regularization is crucial in most applications but is, for computational reasons, commonly limited to a small collection of parameter values. This paper presents an algorithm where the solutions for all possible values of the regularization parameter are computed at roughly the same computational complexity previously required to obtain a single solution. Such a collection of solutions is known as a regularization path. Knowledge of the entire regularization path not only aids model selection, but may also provide new information about a, data set. We illustrate this potential of the method in two applications;one where we establish a sensible ordering among a set of corpora callosa outlines, and one where ischemic segments of the myocardium are detected in patients with acute myocardial infarction. (C) 2007 Elsevier B.V. All rights reserved.
We introduce a path following algorithm for L-1-regularized generalized linear models. The L-1-regularization procedure is useful especially because it, in effect, selects variables according to the amount of penaliza...
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We introduce a path following algorithm for L-1-regularized generalized linear models. The L-1-regularization procedure is useful especially because it, in effect, selects variables according to the amount of penalization on the L-1-norm of the coefficients, in a manner that is less greedy than forward selection-backward deletion. The generalized linear model path algorithm efficiently computes solutions along the entire regularization path by using the predictor-corrector method of convex optimization. Selecting the step length of the regularization parameter is critical in controlling the overall accuracy of the paths;we suggest intuitive and flexible strategies for choosing appropriate values. We demonstrate the implementation with several simulated and real data sets.
We consider the problem of approximating a sequence of data points with a "nearly-isotonic," or nearly-monotone function. This is formulated as a convex optimization problem that yields a family of solutions...
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We consider the problem of approximating a sequence of data points with a "nearly-isotonic," or nearly-monotone function. This is formulated as a convex optimization problem that yields a family of solutions, with one extreme member being the standard isotonic regression fit. We devise a simple algorithm to solve for the path of solutions, which can be viewed as a modified version of the well-known pool adjacent violators algorithm, and computes the entire path in O(n log n) operations (n being the number of data points). In practice, the intermediate fits can be used to examine the assumption of monotonicity. Nearly-isotonic regression admits a nice property in terms of its degrees of freedom: at any point along the path, the number of joined pieces in the solution is an unbiased estimate of its degrees of freedom. We also extend the ideas to provide "nearly-convex" approximations.
Multi-constrained optimal path (MCOP) problem which belongs to the path planning widely exists in many fields such as intelligent transportation systems, computer network and communication systems. Based on the netw...
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Multi-constrained optimal path (MCOP) problem which belongs to the path planning widely exists in many fields such as intelligent transportation systems, computer network and communication systems. Based on the network with multiple constraints on each link, the paper conducted an in-depth study on model and algorithm of the MCOP problem, which includes: Establish a MCOP problem model based on road transportation network;Propose a MCOP algorithm;By introducing heuristic idea into the research of MCOP problem, design an exact A*COP algorithm;Prove through experiments the validity of the two algorithms and the superiority of A*COP algorithm.
Topological theory of ventilation network is the basis of mine ventilation simulation system. But there still exists disparity and insufficiency between theory and application. On the basis of in-depth study of ventil...
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The One-Class Support Vector Machine (OC-SVM) is all unsupervised learning algorithm, identifying unusual or outlying points (outliers) from a given dataset. In OC-SVM, it is required to set the regularization hyperpa...
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ISBN:
(纸本)9783540877318
The One-Class Support Vector Machine (OC-SVM) is all unsupervised learning algorithm, identifying unusual or outlying points (outliers) from a given dataset. In OC-SVM, it is required to set the regularization hyperparameter and kernel hyperparameter in order to obtain a good estimate. Generally, cross-validation is often used which requires multiple runs with different hyperparameters, making it very slow. Recently, the solution path algorithm becomes popular. It can obtain every solution for all hyperparameters in a single run rather than re-solve the optimization problem multiple times. Generalizing from previous algorithms for solution path in SVMs, this paper proposes a complete set of solution path algorithms for OC-SVM, including a v-path algorithm and a kernel-path algorithm. In the kernel-path algorithm, a new method is proposed to avoid the failure of algorithm due to indefinite matrix. Using those algorithms, we call obtain the optimum hyperparameters by computing all entire path solution with the computational cost O(n(2) + cnm(3)) on v-path algorithm or O(cn(3) + cnm(3)) on kernel-path algorithm or (c: constant, n: the number of sample, m: the number of sample which on the margin).
Stand-level forest management prescriptions for federal forests in the interior northwest (USA) have changed emphasis in the past decade from being influenced by economic criteria to being influenced by ecological cri...
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Stand-level forest management prescriptions for federal forests in the interior northwest (USA) have changed emphasis in the past decade from being influenced by economic criteria to being influenced by ecological criteria. The design of forest management prescriptions that maintain stand density levels within a target range is now preferred over the design of prescriptions that maximize net present value. We describe a stand-level optimization process for developing efficient management regimes that uses dynamic programming and a region-limited search strategy. The process develops management regimes by penalizing deviations from a preferred range of stand density. Operational considerations, such as minimum harvest levels, can be important, and are considered as constraints in this modeling process. The timing of harvests is such that entries are only permitted when a minimum harvest can be obtained, when a minimum residual basal area can be maintained, and when harvests are limited to trees with a certain diameter range. Lists of residual, harvested, and dead tree records are available for each decade of the optimal regime. These records of information can facilitate further forest product or habitat suitability analysis associated with forest policy analyses. (c) 2005 Elsevier B.V. All rights reserved.
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