Implementation, study and calibration of a modified ASM2d for the simulation of SBR processes

2001 ◽  
Vol 43 (3) ◽  
pp. 69-76 ◽  
Author(s):  
s. Marsili Libelli ◽  
P. Ratini ◽  
A. Spagni ◽  
G. Bortone
Keyword(s):  
Process Model ◽  
Block Diagram ◽  
Basic Mechanism ◽  
Calibration Procedure ◽  
Sensitivity Study ◽  
Trajectory Sensitivity ◽  
Error Functional ◽  
Calibration Accuracy ◽  
Static Sensitivity ◽  
The Error Functional

An enhanced process model for SBRs has been developed. Though the basic mechanism largely draws on the Activated Sludge Model n. 2d, its new features are the splitting of the nitrification stage in a two-step process, according to the well known Nitrosomonas - Nitrobacter oxidation sequence, and an improved XPAO dynamics, involved in the anaerobic/aerobic phosphorus removal process. The model was implemented through the DLL technique allowing complied C++ modules to be linked to an ordinary Simulink block diagram. The static sensitivity study revealed that if the parameter vector is partitioned into subsets of biologically related parameters and calibrated separately, the calibration procedure does not present particularly difficult aspects. Trajectory sensitivity showed also to which extent data collection could be optimised in order to improve calibration accuracy. The study of the shape of the error functional generated by parameters couples allows a much more effective calibration strategy.

Improving the Generalization Properties of Radial Basis Function Neural Networks

1991 ◽  
Vol 3 (4) ◽  
pp. 579-588 ◽  
Author(s):  
Chris Bishop
Keyword(s):  
Neural Networks ◽  
Radial Basis Function ◽  
Basis Function ◽  
Learning Algorithm ◽  
Error Functional ◽  
Radial Basis ◽  
The Error Functional ◽  
Network Mapping ◽  
Nonlinear Mappings

An important feature of radial basis function neural networks is the existence of a fast, linear learning algorithm in a network capable of representing complex nonlinear mappings. Satisfactory generalization in these networks requires that the network mapping be sufficiently smooth. We show that a modification to the error functional allows smoothing to be introduced explicitly without significantly affecting the speed of training. A simple example is used to demonstrate the resulting improvement in the generalization properties of the network.

scholarly journals Calibration of a nutrient flow model of energy utilization by growing pigs

2001 ◽  
Vol 86 (6) ◽  
pp. 675-689 ◽  
Author(s):  
Stephen Birkett ◽  
Kees de Lange
Keyword(s):  
Process Model ◽  
Calibration Procedure ◽  
Growing Pigs ◽  
Energy Utilization ◽  
Metabolic Effects ◽  
Energetic Efficiency ◽  
Body Protein ◽  
Energy Flows ◽  
Model Response ◽  
Maintenance Requirements

A computational framework to represent energy utilization for body protein and lipid accretion by growing pigs is presented. Nutrient and metabolite flows, and the biochemical and biological processes which transform these, are explicitly represented in this nutritional process model. A calibration procedure to adjust the marginal input–output response is described, and applied, using reported experimental results, to determine a complete set of parameters for representing energy utilization by growing pigs. A reasonable value for minimum basal energy requirements is also determined. Although model inputs and outputs need not at any time be converted to equivalent energy flows, to facilitate comparison of model response with that of conventional energy-based models, a simple means to estimate energy flows from model-predicted nutrient flows is described. The well-known hierarchy of marginal (biological) energetic efficiencies with which pigs use different classes of nutrients is predicted by the model, based only on simple biological and biochemical principles. The significance of independent diet and metabolic effects on both energetic efficiency and maintenance requirements is examined using model predictions from simulated experiments.

scholarly journals Learning Precise Spike Train–to–Spike Train Transformations in Multilayer Feedforward Neuronal Networks

2016 ◽  
Vol 28 (5) ◽  
pp. 826-848 ◽  
Author(s):  
Arunava Banerjee
Keyword(s):  
Spike Train ◽  
Gradient Descent ◽  
Probabilistic Models ◽  
Spike Timing ◽  
Inhibitory Neurons ◽  
Closed Form Solutions ◽  
Learning Framework ◽  
Error Functional ◽  
The Error Functional ◽  
Quantities Of Interest

We derive a synaptic weight update rule for learning temporally precise spike train–to–spike train transformations in multilayer feedforward networks of spiking neurons. The framework, aimed at seamlessly generalizing error backpropagation to the deterministic spiking neuron setting, is based strictly on spike timing and avoids invoking concepts pertaining to spike rates or probabilistic models of spiking. The derivation is founded on two innovations. First, an error functional is proposed that compares the spike train emitted by the output neuron of the network to the desired spike train by way of their putative impact on a virtual postsynaptic neuron. This formulation sidesteps the need for spike alignment and leads to closed-form solutions for all quantities of interest. Second, virtual assignment of weights to spikes rather than synapses enables a perturbation analysis of individual spike times and synaptic weights of the output, as well as all intermediate neurons in the network, which yields the gradients of the error functional with respect to the said entities. Learning proceeds via a gradient descent mechanism that leverages these quantities. Simulation experiments demonstrate the efficacy of the proposed learning framework. The experiments also highlight asymmetries between synapses on excitatory and inhibitory neurons.

Preventive Maintenance and Spare Parts Management Optimization in Natural Gas Pipelines Operating Under Variable Conditions Across the Year

2015 ◽  
Author(s):  
Elisa Carlucci ◽  
Leonardo Tognarelli
Keyword(s):  
Gas Turbines ◽  
Block Diagram ◽  
Sensitivity Study ◽  
Spare Parts ◽  
Pipeline Architecture ◽  
Gas Generator ◽  
Natural Gas Pipelines ◽  
Spare Parts Management ◽  
The Impact ◽  
Very High

Pipeline architecture consists in several stations in series configuration; hence the unavailability of one station impacts the availability of the whole pipeline. This lead to the need of optimizing the availability of each station in terms of configuration and number of units required in order to be able of satisfying the demand at any time. The loss of production cost in gas supply application is very high. Aero-derivatives gas Turbines are typically used as drivers in pipeline applications since they maximize train efficiency, minimizing gas consumption. PGT25+ aero-derivative Gas Turbines are among the most popular units applied in pipeline services. They merge demonstrated reliability performances together with a very limited outage duration impact that leads to very high Availability. Outage duration is optimized through modular replacement of both GG and HSPT that is facilitated by light weight of the machine. A Reliability Block Diagram has been built with the aim to optimize the Pipeline PGT25+ Gas Generator scheduled maintenance. Each block represents a Gas Generator while each station is realized taking into account the actual k-out-of-N configuration of each station units. Once the model has been created, a sensitivity analysis has been performed in order to estimate the impact of the Gas Generator cycle time (Gas Generator refurbishment time),that is what if larger or shorter than the baseline 6 months. Further, even a sensitivity study has been carried on to estimate the impact of the number of available spare parts on the delay that some units will suffer due to un-sufficient number of GG spare with consequent higher risk.

scholarly journals TOP EVALUATION FOR THE RA TION FOR THE RATE OF FUNC TE OF FUNCTIONAL OF ERROR AL OF ERROR WEIGHT CUBATURE FORMUL TURE FORMULA IN SP A IN SPACE

2019 ◽  
Vol 3 (4) ◽  
pp. 32-37
Author(s):  
Ozodjon Isomidinovich Jalolov ◽  
◽  
Khurshidzhon Usmanovich Khayatov
Keyword(s):  
Sobolev Space ◽  
Upper Bound ◽  
Cubature Formula ◽  
Integration Formulas ◽  
Error Functional ◽  
The Error Functional ◽  
Error Weight ◽  
Norm Of The Error ◽  
Approximate Integration

An upper bound is obtained for the norm of the error functional of the weight cubature formula in the Sobolev space . The modern formulation of the problem of optimization of approximate integration formulas is to minimize the norm of the error functional of the formula on the selected normalized spaces. In these works, the problem of optimality with respect to some definite space is investigated. Most of the problems are considered in the Sobolev space

scholarly journals A sensitivity study for far infrared balloon-borne limb emission sounding of stratospheric trace gases

2013 ◽  
Vol 3 (1) ◽  
pp. 251-303 ◽  
Author(s):  
J. Xu ◽  
F. Schreier ◽  
P. Vogt ◽  
A. Doicu ◽  
T. Trautmann
Keyword(s):  
Automatic Differentiation ◽  
Trace Gases ◽  
Nonlinear Least Squares ◽  
Far Infrared ◽  
Calibration Procedure ◽  
Sensitivity Study ◽  
Iterative Regularization ◽  
Pointing Error ◽  
Infrared Measurements ◽  
Nonlinearity Effect

Abstract. This paper presents a sensitivity study performed for trace gases retrieval from synthetic observations by TELIS (TErahertz and submillimeter LImb Sounder) which is a stratospheric balloon-borne cryogenic heterodyne spectrometer. Issues pertaining to hydroxyl radical (OH) retrieval from the far infrared measurements by the 1.8 THz channel are addressed. The study is conducted by a retrieval code PILS (Profile Inversion for Limb Sounding) developed to solve the nonlinear inverse problems arising in the analysis of infrared/microwave limb sounding measurements. PILS combines a line-by-line forward model with automatic differentiation for computing Jacobians and employs regularized nonlinear least squares inversion. We examine the application of direct and iterative regularization methods and evaluate the performance of single- and multi-profile retrievals. Sensitivities to expected errors in calibration procedure, instrumental knowledge and atmospheric profiles have been analyzed. Nonlinearity effect, inaccurate sideband ratio, and pointing error turned out to be the dominant error sources. Furthermore, the capability of multi-channel simultaneous retrieval from the far infrared and submillimeter data has been investigated. The errors and averaging kernels infer that the quality of the obtained hydrogen chloride (HCl) can be improved by significantly better exploitation of information from the observations.

scholarly journals The Modified Trapezoidal Rule for Computing Hypersingular Integral on Interval

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Jin Li ◽  
Xiuzhen Li
Keyword(s):  
Error Function ◽  
Quadrature Rule ◽  
Posteriori Error ◽  
Trapezoidal Rule ◽  
Boundary Element Methods ◽  
Posteriori Error Estimate ◽  
Order Of Accuracy ◽  
Hypersingular Integrals ◽  
Error Functional ◽  
The Error Functional

The modified trapezoidal rule for the computation of hypersingular integrals in boundary element methods is discussed. When the special function of the error functional equals zero, the convergence rate is one order higher than the general case. A new quadrature rule is presented and the asymptotic expansion of error function is obtained. Based on the error expansion, not only do we obtain a high order of accuracy, but also a posteriori error estimate is conveniently derived. Some numerical results are also reported to confirm the theoretical results and show the efficiency of the algorithms.

A Review of Application of Sensitivity in Power System

2014 ◽  
Vol 494-495 ◽  
pp. 1670-1673
Author(s):  
Xue Song Zhou ◽  
Xue Qi Shi ◽  
You Jie Ma
Keyword(s):  
Power System ◽  
Analysis Method ◽  
Trajectory Sensitivity ◽  
Independent Variable ◽  
Static Sensitivity ◽  
Sensitivity Method ◽  
And Control ◽  
Relationship Of ◽  
Physical Quantities ◽  
Differential Relationship

Sensitivity method is to get the level of sensitivity of dependent variable to independent variable by using differential relationship of some physical quantities in the system. It has been widely used in the analysis and control of power system. From the point of time, sensitiveness analysis method can be divided into two categories, static sensitivity and trajectory sensitivity. And according to the different considered variables, they are reviewed respectively in this paper. Application of sensitiveness analysis method in the power system reflects essential research value.

METHODOLOGY FOR MODELING AND ENSURING INFORMATION SECURITY IN RESOURCE MANAGEMENT

2021 ◽  
pp. 45-52
Author(s):  
D. A. Zakoldaev ◽  
A. Yu. Grishentsev
Keyword(s):  
Resource Management ◽  
Information Security ◽  
Security Policy ◽  
Process Model ◽  
Block Diagram ◽  
Structural Modeling ◽  
The State ◽  
Risk Minimization ◽  
Technological Processes ◽  
Resource Transformation

The subject of research is an information security in resource management based on the mapping of technological processes of transformation and movement of resources into the phase space. The aim of the research is to develop a methodology, as a set of methods and tools united by a common ideology for information security. The methodology is formed by a set of the following methods and means: method and means of structural modeling, information security analysis and construction of production and technological models, in the form of executable block diagrams, based on predefined block elements of production and technological processes; method and tools of integrating an adversary into the production and technological process model, as a structural part of the executable block diagram of the production and technological model; a method for analyzing and selecting the trajectory of resource movement in the production and technological space based on structural modeling using optimization methods based on the risk minimization criterion for given values of acceptable and acceptable ranges (min,max) of resource transformation and changes in the state of production processes. The set of developed methods is united by the following ideology: methods and tools of forming an information security policy for objects of all levels of the hierarchy of the traffic management system and resource transformation. The result of the research is the formalization of the methodology and the methods and tools that form it to the level of readiness of application to solve practical problems. The scope of application of the proposed methodology and its methods and tools: solving problems of information security at enterprises and in industries by modeling, monitoring and analyzing the trajectories of the movement of resources and the state of production and technological processes.

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