Infinitesimal Idealization, Easy Road Nominalism, and Fractional Quantum Statistics

It has been recently debated whether there exists a so-called “easy road” to nominalism. In this essay, I attempt to fill a lacuna in the debate by making a connection with the literature on infinite and infinitesimal idealization in science through an example from mathematical physics that has been largely ignored by philosophers. Specifically, by appealing to John Norton’s distinction between idealization and approximation, I argue that the phenomena of fractional quantum statistics bears negatively on Mary Leng’s proposed path to easy road nominalism, thereby partially defending Mark Colyvan’s claim that there is no easy road to nominalism

One real gauge potential is one too many

To single one out of the infinitely many, empirically indistinguishable gauge potentials of classical electrodynamics, and to deem it `more real' than the rest is not trivial. Only two routes are open to one who might attempt to do so. The first leads to a slippery slope: if one singles out a potential solely by requiring it to admit well behaved propagations, and on the strength of this behavior one subscribes to its reality, one inevitably subscribes to the reality of infinitely many. As for the second, it seems to be barred from the beginning. But if, for reasons of metaphysical economy, one insisted on taking it, it would lead to a `truncated theory' that is physically and empirically inferior to the complete

Multiscale estimation of the Freundlich adsorption isotherm

Adsorption plays an important role in water and wastewater treatment. The analysis and design of processes that involve adsorption rely on the availability of isotherms that describe these adsorption processes. Adsorption isotherms are usually estimated empirically from measurements of the adsorption process variables. Unfortunately, these measurements are usually contaminated with errors that degrade the accuracy of estimated isotherms. Therefore, these errors need to be filtered for improved isotherm estimation accuracy. Multiscale wavelet based filtering has been shown to be a powerful filtering tool. In this work, multiscale filtering is utilized to improve the estimation accuracy of the Freundlich adsorption isotherm in the presence of measurement noise in the data by developing a multiscale algorithm for the estimation of Freundlich isotherm parameters. The idea behind the algorithm is to use multiscale filtering to filter the data at different scales, use the filtered data from all scales to construct multiple isotherms and then select among all scales the isotherm that best represents the data based on a cross validation mean squares error criterion. The developed multiscale isotherm estimation algorithm is shown to outperform the conventional time-domain estimation method through a simulated example

Wavelet-based Multiscale Filtering of Genomic Data

Measured biological data are a rich source of information about the biological phenomena they represent. For example, time-series genomic or metabolic microarray data can be used to construct dynamic genetic regulatory network models, which can be used to better understand the biological system and to design intervention strategies to cure or manage major diseases. Unfortunately, biological measurements are usually highly contaminated with errors that mask the important features in the data. Therefore, these noisy measurements need to be filtered to enhance their usefulness in practice. Wavelet-based multiscale filtering has been shown to be a powerful data analysis and denoising tool. In this work, different batch as well as online multiscale filtering techniques are used to filter biological data contaminated with white noise. The performances of these multiscale filtering techniques are demonstrated and compared to those of some conventional low pass filters using simulated time series metabolic data. The results of this comparative study show that significant improvement can be achieved using multiscale filtering over conventional filtering methods. 2012 IEEE.Scopu

Parameter estimation of biological phenomena: An unscented kalman filter approach

Recent advances in high-throughput technologies for biological data acquisition have spurred a broad interest in the construction of mathematical models for biological phenomena. The development of such mathematical models relies on the estimation of unknown parameters of the system using the time-course profiles of different metabolites in the system. One of the main challenges in the parameter estimation of biological phenomena is the fact that the number of unknown parameters is much more than the number of metabolites in the system. Moreover, the available metabolite measurements are corrupted by noise. In this paper, a new parameter estimation algorithm is developed based on the stochastic estimation framework for nonlinear systems, namely the unscented Kalman filter (UKF). A new iterative UKF algorithm with covariance resetting is developed in which the UKF algorithm is applied iteratively to the available noisy time profiles of the metabolites. The proposed estimation algorithm is applied to noisy time-course data synthetically produced from a generic branched pathway as well as real time-course profile for the Cad system of E. coli. The simulation results demonstrate the effectiveness of the proposed scheme. 2004-2012 IEEE.Scopu

Intervention in biological phenomena modeled by S-systems

Recent years have witnessed extensive research activity in modeling biological phenomena as well as in developing intervention strategies for such phenomena. S-systems, which offer a good compromise between accuracy and mathematical flexibility, are a promising framework for modeling the dynamical behavior of biological phenomena. In this paper, two different intervention strategies, namely direct and indirect, are proposed for the S-system model. In the indirect approach, the prespecified desired values for the target variables are used to compute the reference values for the control inputs, and two control algorithms, namely simple sampled-data control and model predictive control (MPC), are developed for transferring the control variables from their initial values to the computed reference ones. In the direct approach, a MPC algorithm is developed that directly guides the target variables to their desired values. The proposed intervention strategies are applied to the glycolyticglycogenolytic pathway and the simulation results presented demonstrate the effectiveness of the proposed schemes. 2006 IEEE.Qatar Foundation; Qatar National Research FundScopu