In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well kn...In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well known <em>factorization method</em>, in which a computationally effective numerical scheme for the reconstruction of the shape of the scatterer is presented. This is possible, due to a <em>mixed reciprocity principle</em>, which renders the computation of the Green function at the background medium unnecessary. Moreover, to further refine our inversion algorithm, an efficient Tikhonov parameter choice technique, called <em>Improved Maximum Product Criterion</em> (IMPC) is exploited. Our regularization parameter is computed via a fast iterative algorithm which requires no <em>a priori</em> knowledge of the noise level in the far-field data. Finally, the effectiveness of IMPC is illustrated with various numerical examples.展开更多
In the present article we study the production of grape molasses. Data drawn from a specified biolaboratory, are properly analyzed in order to detect factors that affect significantly the Brix value and the volatile a...In the present article we study the production of grape molasses. Data drawn from a specified biolaboratory, are properly analyzed in order to detect factors that affect significantly the Brix value and the volatile acidity of the final product. The ground that is used for planting and a variety of grapes have been taken into account. Off-line statistical quality control techniques have been employed and the outcomes are displayed and discussed in detail.展开更多
This paper has focused on applying mathematical techniques to address fundamental question in therapy planning when to switch, and how to sequence therapies. We consider switching and sequencing available therapies so...This paper has focused on applying mathematical techniques to address fundamental question in therapy planning when to switch, and how to sequence therapies. We consider switching and sequencing available therapies so as to maximize a patient＇s expected total lifetime. We assume knowledge only about the lifetime distributions induced by the therapies. We discuss a specialization of this model that is tailored to a frequently reoccurring type of management problem, where our goal is to determine the best timing for testing and treatment decisions for patients with ischemic heart disease. Typically, decisions are made with an overall, goal of maximizing the patient＇s expected lifetime or quality-adjusted lifetime.展开更多
文摘In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well known <em>factorization method</em>, in which a computationally effective numerical scheme for the reconstruction of the shape of the scatterer is presented. This is possible, due to a <em>mixed reciprocity principle</em>, which renders the computation of the Green function at the background medium unnecessary. Moreover, to further refine our inversion algorithm, an efficient Tikhonov parameter choice technique, called <em>Improved Maximum Product Criterion</em> (IMPC) is exploited. Our regularization parameter is computed via a fast iterative algorithm which requires no <em>a priori</em> knowledge of the noise level in the far-field data. Finally, the effectiveness of IMPC is illustrated with various numerical examples.
文摘In the present article we study the production of grape molasses. Data drawn from a specified biolaboratory, are properly analyzed in order to detect factors that affect significantly the Brix value and the volatile acidity of the final product. The ground that is used for planting and a variety of grapes have been taken into account. Off-line statistical quality control techniques have been employed and the outcomes are displayed and discussed in detail.
文摘This paper has focused on applying mathematical techniques to address fundamental question in therapy planning when to switch, and how to sequence therapies. We consider switching and sequencing available therapies so as to maximize a patient＇s expected total lifetime. We assume knowledge only about the lifetime distributions induced by the therapies. We discuss a specialization of this model that is tailored to a frequently reoccurring type of management problem, where our goal is to determine the best timing for testing and treatment decisions for patients with ischemic heart disease. Typically, decisions are made with an overall, goal of maximizing the patient＇s expected lifetime or quality-adjusted lifetime.
