Mohammad Salehi

2papers

2 Papers

LGDec 9, 2020
Federated Learning in Unreliable and Resource-Constrained Cellular Wireless Networks

Mohammad Salehi, Ekram Hossain

With growth in the number of smart devices and advancements in their hardware, in recent years, data-driven machine learning techniques have drawn significant attention. However, due to privacy and communication issues, it is not possible to collect this data at a centralized location. Federated learning is a machine learning setting where the centralized location trains a learning model over remote devices. Federated learning algorithms cannot be employed in the real world scenarios unless they consider unreliable and resource-constrained nature of the wireless medium. In this paper, we propose a federated learning algorithm that is suitable for cellular wireless networks. We prove its convergence, and provide the optimal scheduling policy that maximizes the convergence rate. We also study the effect of local computation steps and communication steps on the convergence of the proposed algorithm. We prove, in practice, federated learning algorithms may solve a different problem than the one that they have been employed for if the unreliability of wireless channels is neglected. Finally, through numerous experiments on real and synthetic datasets, we demonstrate the convergence of our proposed algorithm.

NAMar 18, 2015
A more robust multiparameter conformal mapping method for geometry generation of any arbitrary ship section

Mohammad Salehi, Parviz Ghadimi, Ali Bakhshandeh Rostami

The central problem of strip theory is the calculation of potential flowaround 2D sections. One particular method of solutions to this problem is conformal mapping of the body section to the unit circle over which a solution of potential flow is available. Here, a new multiparameter conformal mapping method is presented that can map any arbitrary section onto a unit circle with good accuracy. The procedure for finding the corresponding mapping coefficients is iterative. The suggested mapping technique is shown to be capable of appropriately mapping any chined, bulbous, and large and fine sections. Several examples of mapping symmetric and nonsymmetric sections are demonstrated. For symmetric and nonsymmetric sections, the results of the current method are compared against other mapping techniques, and the currently produced geometries display good agreement with the actual geometries.