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Evaluation of a new local modelling approach for large and heterogeneous NIRS data sets

CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS 2010年第2期101卷 87-94页

作者： Zamora-Rojas, E. Garrido-Varo, A. Van den Berg, F. Guerrero-Ginel, J. E. Perez-Marin, D. C. Univ Cordoba Fac Agr & Forestry Engn Dept Anim Prod E-14071 Cordoba Spain Univ Copenhagen Fac Life Sci Dept Food Sci DK-1168 Copenhagen Denmark

The industry is demanding quality control systems that enable not only certified safety of an end-product but also a secure and efficient production system. Due to this, fast and accurate technologies are required for developing real time decision systems. Sensors based on Near-Infrared Spectroscopy (NIRS), together with the use of chemometrics models, have been studied for on-line quality control as a Process Analytical Technology (PAT) tool in several industries. A critical issue is the development of robust and sufficiently accurate mathematical models that can contain hundreds of very heterogeneous samples representing the large natural variability of the process and product: this especially holds for the agro-food production. This paper evaluates the performance of different linear (PLS) and non-linear regression algorithms (LOCAL and Locally Weighted Regression - LWR) plus a new local approach for the prediction of ingredient composition in compound feeds (called, Local Central Algorithm - LCA). The comparison is based on complexity, accuracy and predicted percentages in test set samples. The new local modelling approach is based on the use of Principal Component Analysis (PCA) and the Mahalanobis Distance (MD) for selecting a training set and calculating the final prediction estimate using a central tendency statistics such as mean of the local neighbours for the unknown samples. The results show that the local strategy proposed in this work enables the prediction in seconds of all the unknown samples in the test set and performed comparable to LWR, although the RMSEP was somewhat higher than using LWR or LOCAL However, it was found that this approach produced smaller prediction errors than the other methods for less commonly present ingredients that are not well represented by even a large number of training samples. This finding could be relevant for the start-up phase in the implementation of NIRS sensors in the feed industry at which stage the libraries b

关键词： NIRS non-linear algorithms Local Central Algorithm Robust calibrations Compound feed Ingredient composition

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Performance Evaluation Of Polynomial Congestion Control algorithms In Mobile Ad Hoc TCP Networks

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IETE JOURNAL OF RESEARCH 2007年第4期53卷 329-337页

作者： Chandrasekaran, M. Banu, R. S. D. Wahida Govt Coll Engn Dept ECE Salem 636011 India

[ABST].

关键词： congestion control TCP non-linear algorithms AIMD ns2 mobile ad hoc networks

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Development of a direct-solution algorithm for determining the optimal crop planning of farms using deficit irrigation

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AGRICULTURAL WATER MANAGEMENT 2016年 171卷 173-187页

作者： Lopez-Mata, E. Orengo-Valverde, J. J. Tarjuelo, J. M. Martinez-Romero, A. Dominguez, A. Univ Castilla La Mancha Escuela Tecn Super Ingn Agronomos & Montes CREA Campus Univ S-N Albacete 02071 Spain Univ Castilla La Mancha Dept Matemat Area Matemat Aplicada Campus Univ S-N Albacete 02071 Spain

The irrigation farms placed in areas of scare water demand methodologies that can increase their profitability via more efficient use of their resources. Determining the combination of factors that maximizes the profitability of any productive process requires the use of optimization methodologies. Traditionally, these types of problems were solved using heuristic methods. However, a direct-solution algorithm would produce faster and more accurate solutions. The aim of this work was to develop a direct-solution algorithm capable of determining the crop planning (area and volume of water per crop) that maximizes the profitability of an irrigation farm. The data required by the algorithm include the total cultivable area of the farm and the amount of available irrigation water as well as the "gross margin vs. irrigation depth" functions of the considered crops. Cultivating one or two crops is the way to reach higher profitability, but this strategy is not suitable from an agricultural point of view (i.e., crop rotation, diseases, weather risks, regulations of agricultural policies, etc.). Due to this algorithm must be compatible with the MOPECO model, a methodology has been developed to allow its implementation in this model. The objective of this software is to maximize the profitability of irrigation farms by incorporating a more efficient use of irrigation water using regulated deficit irrigation techniques. The current version of this model uses genetic algorithms for determining optimal crop planning, which are time consuming. For a hypothetical 100 ha farm, considering 10 different crops and 11 scenarios of water availability, the developed algorithm adapted to MOPECO achieved gross margins around 0.5% lower than LINGO, and 1.1% higher than genetic algorithms, decreasing the calculation time requirements by between 50 and 100 and approximately 2000 times, respectively. Another relevant result is the fact that the algorithm may be used manually, by drawing the ta

关键词： MOPECO Semiarid non-linear algorithms Model

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Solving first-order initial-value problems by using an explicit non-standard A-stable one-step method in variable step-size formulation

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APPLIED MATHEMATICS AND COMPUTATION 2015年 268卷 796-805页

作者： Ramos, Higinio Singh, Gurjinder Kanwar, V. Bhatia, Saurabh Univ Salamanca Sci Comp Grp E-37008 Salamanca Spain Escuela Politecn Super Zamora Zamora 49022 Spain Panjab Univ Univ Inst Engn & Technol Chandigarh 160014 India

This paper presents the construction of a new family of explicit schemes for the numerical solution of initial value problems of ordinary differential equations (ODEs). The one parameter family is constructed by considering a suitable rational approximation to the theoretical solution, resulting a family with second order convergence and A-stable. Imposing that the principal term in the local truncation error vanishes, we obtain an expression for the parameter value in terms of the point (x(n), y(n)) on each step. With this approach, the resulting method has third order convergence maintaining the characteristic of A-stability. Finally, combining this last method with other of order two in order to get an estimation for the local truncation error, an implementation in variable step size has been considered. The proposed method can be used in a wide range of problems, for solving numerically a scalar ODE or a system of first order ODEs. Several numerical examples are given to illustrate the efficiency and performance of the proposed method in comparison with some existing methods in the literature. (C) 2015 Elsevier Inc. All rights reserved.

关键词： non-linear algorithms Ordinary differential equations Initial value problems Rational approximation Stability

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Performance evaluation of nonlinear algorithms with line-search for partitioned coupling techniques for fluid-structure interactions

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 2010年第10-12期64卷 1129-1147页

作者： Minami, S. Yoshimura, S. Univ Tokyo Dept Quantum Engn & Syst Sci Bunkyo Ku Tokyo 1138656 Japan Univ Tokyo Dept Syst Innovat Bunkyo Ku Tokyo 1138656 Japan

Recently tightly coupled partitioned iterative methods have drawn a great deal of attention due to easy implementation and encapsulation features, and many nonlinear algorithms have been proposed so far. However, their practical performances have not been well understood yet. This paper describes the intensive parametric study on convergence and stability performances of four kinds of nonlinear algorithms with line-search techniques for partitioned iterative methods of steady/unsteady fluid-structure interaction (FSI) problems. Here we choose three typical FSI problems as test problems, i.e. (1) Collapsible channel as a steady problem, (2) Cavity with flexible bottom membrane and (3) Channel with flexible wall as unsteady problems. Efficiency and robustness dependency of those nonlinear algorithms on physical parameters such as degree of nonlinearity, added mass effect, time step, and control parameters peculiar to each algorithm are clarified. Through those tests, we demonstrate that the Line extrapolation method and Broyden method with Backtrack line-search technique show good performances in both stability and efficiency. Copyright (C) 2010 John Wiley & Sons, Ltd.

关键词： partitioned iterative method non-linear algorithms line-search techniques fluid-structure interaction problems

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Self-adaptive separation of convolutively mixed signals with a recursive structure. Part I: Stability analysis and optimization of asymptotic behaviour

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SIGNAL PROCESSING 1999年第3期73卷 225-254页

作者： Charkani, N Deville, Y Labs Elect Philips SAS F-94453 Limeil Brevannes France

In this paper, we investigate the self-adaptive source separation problem for convolutively mixed signals. The proposed approach uses a recurrent structure adapted by a generic rule involving arbitrary separating functions. A stability analysis of this algorithm is first performed. It especially applies to some classical rules for instantaneous and convolutive mixtures that were proposed in the literature but only partly analysed, The expression of the asymptotic error variance is then determined for strictly causal mixtures. This enables to derive the optimum separating functions that minimize this error variance. They are shown to be only related to the probability density functions of the sources. To perform this error minimization, two normalization procedures that improve the algorithm properties are proposed. Their stability conditions and their asymptotic behaviour are analysed. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： asymptotic behaviour optimization blind source separation convolutive mixtures higher-order statistics non-linear algorithms ordinary differential equation recurrent structure self-adaptive algorithms stability analysis

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Self-adaptive separation of convolutively mixed signals with a recursive structure. Part II: Theoretical extensions and application to synthetic and real signals

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SIGNAL PROCESSING 1999年第2期75卷 117-140页

作者： Charkani, N Deville, Y Univ Toulouse 3 LAMI F-31400 Toulouse France

This paper deals with the separation of two convolutively mixed signals. The proposed approach uses a recurrent structure adapted by generic rules involving arbitrary separating functions. While the basic versions of this approach were defined and analyzed in our companion paper (Charkani and Deville, 1999), two extensions are considered here. The first one is intended for possibly colored signals. In addition, the second one may be used even when the probability density functions of the sources are unknown. We first analyze the convergence properties of these extended approaches at the separating state, i.e. we derive their equilibrium and stability conditions and their asymptotic error variance. We then determine the separating functions which minimize this error variance. We also report experimental results obtained in various conditions, ranging from synthetic data to mixtures of speech signals measured in real situations. These results confirm the validity of the proposed approaches and show that they significantly outperform classical source separation methods in the considered conditions. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： asymptotic behavior optimization blind source separation colored signals convolutive mixtures non-linear algorithms recurrent network self-adaptive algorithms speech processing stability analysis sub-optimum non-linear functions

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Investigations on the approximability and computability of the Hilbert transform with applications

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APPLIED AND COMPUTATIONAL HARMONIC ANALYSIS 2020年第2期48卷 706-730页

作者： Boche, Holger Pohl, Volker Tech Univ Munich Lehrstuhl Theoret Informationstech Arcisstr 21 D-80333 Munich Germany

It was recently shown that on a large class of important Banach spaces there exist no linear methods which are able to approximate the Hilbert transform from samples of the given function. This implies that there is no linear algorithm for calculating the Hilbert transform which can be implemented on a digital computer and which converges for all functions from the corresponding Banach spaces. The present paper develops a much more general framework which also includes non-linear approximation methods. All algorithms within this framework have only to satisfy an axiom which guarantees the computability of the algorithm based on given samples of the function. The paper investigates whether there exists an algorithm within this general framework which converges to the Hilbert transform for all functions in these Banach spaces. It is shown that non-linear methods give actually no improvement over linear methods. Moreover, the paper discusses some consequences regarding the Turing computability of the Hilbert transform and the existence of computational bases in Banach spaces. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Approximation Hilbert transform Sampling non-linear algorithms Turing computability

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Nutrient optimization for plant growth in Aquaponic irrigation using Machine Learning for small training datasets

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Artificial Intelligence in Agriculture 2022年第1期6卷 68-76页

作者： Sambandh Bhusan Dhal Muthukumar Bagavathiannan Ulisses Braga-Neto Stavros Kalafatis Department of Electrical and Computer Engineering Texas A&M UniversityUSA Department of Soil and Crop Sciences Texas A&M UniversityUSA

With the recent trends in urban agriculture and climate change,there is an emerging need for alternative plant culture techniques where dependence on soil can be *** and aquaponic growth techniques have proven to be viable alternatives,but the lack of efficient and optimal practices for irrigation and nutrient supply limits its applications on a large-scale commercial *** main purpose of this research was to develop statistical methods and Machine Learning algorithms to regulate nutrient concentrations in aquaponic irrigation water based on plant needs,for achieving optimal plant growth and promoting broader adoption of aquaponic culture on a commercial *** of the key challenges to developing these algorithms is the sparsity of data which requires the use of Bolstered error estimation *** this paper,several linear and non-linear algorithms trained on relatively small datasets using Bolstered error estimation techniques were evaluated,for selecting the best method in making decisions regarding the regulation of nutrients in hydroponic *** repeated tests on the dataset,it was decided that Semi-Bolstered Resubstitution Error estimation technique works best in our case using linear Support Vector Machine as the classifier with the value of penalty parameter set to one.A set of recommended rules have been prescribed as a Decision Support System,using the output of the Machine Learning algorithm,which have been tested against the results of the baseline ***,the positive impact of the recommended nutrient concentrationson plant growth in aquaponic environments has been elaborately discussed.

关键词： Hydroponic Aquaponic Training datasets non-linear algorithms Semi-bolstered error estimation linear support vector machine Decision Support System

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AN ALGORITHM FOR SEPARABLE nonlinear MINIMAX PROBLEMS

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OPERATIONS RESEARCH LETTERS 1987年第4期6卷 159-162页

作者： LUSS, H AT&T Bell Laboratories Crawfords Corner Road Holmdel NJ 07733 USA

We consider a minimax resource allocation problem in which each term of the objective function is a strictly decreasing, invertible function of a single decision variable. The objective is to minimize the maximum term subject to non-negativity constraints and a set of linear constraints with only non-negative parameters. We develop an algorithm that finds an optimal solution by repeatedly solving a relaxed minimax problem. In general, each relaxed problem is solved by simple search methods; however, for certain non-linear functions the algorithm employs closed form expressions.

关键词： resource allocation large-scale systems non-linear algorithms production scheduling

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