دکتر محسن شیخ حسینی

Concepts and laws of physics have been a valuable source of inspiration for engineers to overcome human challenges and problems. Classification is an important example of such problems that plays a major role in various fields of engineering sciences. It is shown that discriminative classifiers tend to outperform their generative counterparts, especially in the presence of sufficient labeled training data. In this paper, we present a new physics-inspired discriminative classification method using minimum potential line. To do this, we first consider two groups of fixed point charges (as two classes of data) and a movable classifier line between them. Then, we find a stable position for the classifier line by minimizing the total potential integral on the classifier line due to the two groups of point charges. Surprisingly, it will be shown that the obtained classifier is actually an uncertainty-based classifier that minimizes the total uncertainty of the classifier line. The effectiveness of the proposed method is validated by some experiments on both synthetic and real datasets. First, two synthetic datasets are constructed to visually demonstrate the efficiency of the proposed method. Then, some real-world benchmark datasets are selected (from the well-known UCI machine learning repository) to compare the classification performance of the proposed method with three well-known classification methods.

Broadband power line communications (PLC) is a promising candidate for implementing access network of different telecommunication Technologies. Planning process of the PLC access network is subdivided into two main optimization problems of the generalized base station placement and PLC channel allocation.

This paper studies the latter one for an actual PLC network by taking both in-line and in-space neighboring schemes into account for the first time and modeling the PLC channel allocation according to them. In this regards, different aspects of this problem are first introduced in details and then our suggested models for them are presented and numerically evaluated.

Specifically, for each pair of the broadband-PLC cells, in-line neighboring is modeled either by one or zero indicating the cells are neighbor or not; in-space neighboring is suggested to be a number from the interval [0 1] according to physical vicinity of cell’s wirings; and consequently aggregate neighboring intensity will be a number from [0 2]. Subsequently, the network interference is defined as a function of neighboring intensity and assigned frequency sets to the neighbor cells; so that the more neighboring intensity is increased and the more distance between the sets is decreased, the more interference is imposed on the PLC network. Eventually, the meta-heuristic methods of Genetic and shuffled frog-leaping algorithms are exploited to solve resulting PLC channel allocation problem via minimizing the interference.

In general, the results confirmed the success of the suggested method in modeling PLC channel allocation problem in actual scenarios, tracking the network interference in these situations, providing an optimal solution for them, and including all previous research as a comprehensive method. The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.

Design of low-complexity receiver for space-time block coded (STBC) transmission over multiple-input multiple-output (MIMO) multiple-access channels has been subject of interest over the years. In this regard, zero-forcing receiver, as a low complexity receiver needing as many receive antennas as the numbers of users, has received increasing attention.

This paper investigates multiuser detection for STBC transmission over a flat-fading MIMO multiple-access channel consisting of  co-channel users each with  antennas and a zero-forcing coherent receiver equipping with  receiving antennas. For the cases in which , it was previously claimed that it is impossible to extend this receiver to general scenarios of orthogonal STBC transmission with  and .

We provide a theorem allowing this extension to any scenarios satisfying the theorem condition. Describing in more details, we first prove that zero-forcing receiver of  antennas can successfully extend to any STBC transmission over MIMO multiple-access systems which provides an Alamouti-like structure for the inner product of equivalent channels between different receive antennas and users. Then, in order to gain more insight, the theorem role on extending zero-forcing receiver for transmission of orthogonal STBC over MIMO multiple-access systems with  and , and also to other STBC schemes like generalized coordinate interleaved orthogonal design and Quasi-orthogonal STBC is investigated in more details. Finally, the average symbol error rate of considered scenarios are numerically evaluated and compered for different STBC schemes with various numbers of  and .

Generally speaking, it is concluded that extension of zero-forcing receiver to any scenarios of OSTBC transmissions over MIMO multiple-access channels exactly depends on satisfaction of the provided theorem and this receiver can be successfully employed in all scenarios providing an Alamouti-like structure for the inner product of equivalent channels between different receiving antennas and users.