Hybrid Precoding for Multiuser Millimeter Wave Massive MIMO Systems : A Deep Learning Approach

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In multi-user millimeter wave (mmWave) multiple-input-multiple-output (MIMO) systems, hybrid precoding is a crucial task to lower the complexity and cost while achieving a sufficient sum-rate. Previous works on hybrid precoding were usually based on optimization or greedy approaches. These methods either provide higher complexity or have sub-optimum performance. Moreover, the performance of these methods mostly relies on the quality of the channel data. In this work, we propose a deep learning (DL) framework to improve the performance and provide less computation time as compared to conventional techniques. In fact, we design a convolutional neural network for MIMO (CNN-MIMO) that accepts as input an imperfect channel matrix and gives the analog precoder and combiners at the output. The procedure includes two main stages. First, we develop an exhaustive search algorithm to select the analog precoder and combiners from a predefined codebook maximizing the achievable sum-rate. Then, the selected precoder and combiners are used as output labels in the training stage of CNN-MIMO where the input-output pairs are obtained. We evaluate the performance of the proposed method through numerous and extensive simulations and show that the proposed DL framework outperforms conventional techniques. Overall, CNN-MIMO provides a robust hybrid precoding scheme in the presence of imperfections regarding the channel matrix. On top of this, the proposed approach exhibits less computation time with comparison to the optimization and codebook based approaches.Peer reviewe

Modeling and analyzing Ca2+ channel dynamics during cardiac action potential

International Conference on Applied Analysis and Mathematical Modeling (2019 : Istanbul, Turkey)We have studied the cardiac action potential model which consists of 26 nonlinear first-order differential equations in a detailed manner computationally. Later, it has been discussed what is the role of the Ca2+ ion channel to the cardiac action potential by applying a mathematical measure called contribution analysis. Computational simulations are done to analyze the roles of Ca2+ gating variables and detailed analysis showed the changing dynamics of Ca2+ channel during a cardiac action potential.No sponso

Cylindrically Symmetric Vacuum Solutions in Higher Dimensional Brans-Dicke Theory

Higher dimensional, static, cylindrically symmetric vacuum solutions with and without a cosmological constant in the Brans-Dicke theory are presented. We show that, for a negative cosmological constant and for specific values of the parameters, a particular subclass of these solutions include higher dimensional topological black hole-type solutions with a flat horizon topology. We briefly extend our discussion to stationary vacuum and $\Lambda-$vacuum solutions.Comment: V3: Published Versio

How Business Values Determine Lack Of Innovation & Petty Entrepreneurship: The Case Of Turkey

The role of innovation in capitalist development has long been identified. For late industrializing countries, it is indispensable for achieving sustained economic growth. Turkey, as a late industrializer, has also faced serious difficulties in this regard. This paper demonstrates the significance of cultural values internalized by individuals for innovation and business attitudes. In a structure-agency setting, it argues that not only regulation through institutions and social norms but also the way economic agents comprehend modern values determine the scope of business attitude that permeates economy and society. In the Turkish context, the blend of modern (rationalistic) values with traditional ones creates a dilemma between social commitment and blatant opportunism, in time leading to the dominance of short-term profit making in the economy at the expense of societal rules and norms. By conducting linear regression analyses over a sample of 150 executive, middle and owner managers, the article demonstrates how cultural values affect innovativeness. In so doing, it unveils the relations between personality traits underlying the adoption of innovations and different cultural value characteristics

Scanning Hall Probe Microscopy (SHPM) using quartz crystal AFM feedback

[No abstract available

Comparison of posterior cranial fossa morphometric measurements in Chiari type I patients with and without syrinx cavity on magnetic resonance imaging

Purpose: To compare the posterior fossa measurements of Chiari type I malformation (CHM1) patients with and without syrinx and with a control group. Material and methods: The patients with syrinx were divided into 2 groupd according to syrinx width/cord width (S/C) ratios: group 1 – S/C ratio 50%. The length of the clivus, the AP length of the foramen magnum, the AP length of the posterior fossa, the perpendicular distance between the McRae line and (a) the splenium of corpus callosum, (b) the pons, and (c) the fastigium of the 160 patients and of the 160 control patients were statistically compared. In addition, the measurements of the patients with and without syrinx, according to the S/C ratio, were statistically compared. Results: Syrinx was present in 59 (36.8 %) of the 160 patients. The S/C ratio was 50% in 29 (49.1%) of them. All the measurements in the patient group, except of the AP length of the foramen magnum, were statistically significantly lower than in the control group (p = 0.001). There was no signif icant difference in the measurements of the patients with syrinx group 1 and the patients without syrinx, but the AP length of posterior fossa was statistically significantly lower in the patients with syrinx group 2 than the patients without syrinx (p = 0.03). Conclusion: The S/C ratio can be a guide to the underlying aetiology

An International Comparison on Excessive Credit Expansion, Credit Guarantee Programs and The Risks Arising

Crediting in the banking sector plays an important role in all developed and developing countries. For this reason, it is monitored continuously by public authorities and measures are taken to control credit supply in economic growth periods. On the other hand, in an economic slowdown, when banks are reluctant to increase their credit portfolio, public credit guarantee programs are put into use to increase the credit supply. In this study, a sample covering 26 advanced and emerging economies was analyzed, and the effects of credit gap, credit guarantees and economic growth on credits and arising credit risks were investigated. The findings show that both credits and non-performing loans, an important measure of credit risk, are affected by credit gap, credit guarantees, and economic growth. On the one hand, public credit guarantees positively affect economic growth. On the other hand, though they are widely used for supporting small and medium-sized enterprises, our findings suggest that such expansive credit policies might negatively affect the riskiness of the credit portfolios and soundness of the banking sector