Energy-Efficient RIS-Assisted Satellites for IoT Networks

The use of satellites to provide ubiquitous coverage and connectivity for the densely deployed Internet of Things (IoT) networks are expected to be a reality in the emerging 6G networks. Yet, the low battery capacity is of IoT nodes constitute a problem for the direct connectivity to satellites that are located up to 2000 km altitude. As an architectural novelty, in this paper, we propose the use of reconfigurable intelligent surface (RIS) units to help with the path loss associated with high transmission distances. The use of RIS units through broadcasting and beamforming approaches are shown to provide a significant gain in terms of their signal transmission. These units can be placed on the reflectarrays that are already available on the satellites. It is shown that RIS-assisted satellites can provide up to 10^5 times higher downlink and uplink achievable rates for IoT networks.Comment: 8 pages, 6 figure

REDUCING PRODUCT DEFECTS IN APPAREL MANUFACTURING BY USING THE SIX SIGMA METHODOLOGY: A CASE STUDY

WOS: 000342886100012Six Sigma is a statistical methodology aiming to reduce and preclude failures in business processes. Its the foremost principle is that once the number of refuses in any process is discernible, the procedures can be established to systematically prevent them. This paper reports a performance of an implementation of the Six Sigma Methodology in an apparel plant, that has provided an increase of 13% in the manufacturing productivity of trousers by minimization of sewing thread breakage. This accomplishment has been obtained by reducing the thread breakages in the process of the sewing trademark label to the rear center of a trouser

Wireless Power Transmission on Martian Surface for Zero-Energy Devices

Exploration of the Red Planet is essential on the way through both human colonization and establishing a habitat on the planet. Due to the high costs of space missions, the use of distributed sensor networks has been investigated to make in situ explorations affordable. Along with this, the devices with ultra-low-power receivers, which are called zero-energy (ZE) devices, can pave the way to further discoveries about the environment of Mars. This study focuses on wireless power transmission to provide the power required by ZE devices on the Martian surface. The main motivation of this study is to investigate whether conventional harvesters and communication units can supply the required power for a long distance. The numerical results show that it is possible to deliver power to ZE devices without utilizing any sophisticated hardware. In addition, the effects of pointing error and dust storms on harvesting performance are investigated. Comprehensive simulation results reveal that harvester selection and design should be done by considering propagation channel and transmitter characteristics.Comment: to appear in IEEE Transactions on Aerospace and Electronic System

Reconfigurable Intelligent Surfaces Empowered THz Communication in LEO Satellite Networks

The revolution in the low Earth orbit (LEO) satellite networks will bring changes on their communication models and a shift from the classical bent-pipe architectures to more sophisticated networking platforms. Thanks to technological advancements in microelectronics and micro-systems, the terahertz (THz) band has emerged as a strong candidate for inter-satellite links (ISLs) due to its promise of high data rates. Yet, the propagation conditions of the THz band need to be properly modeled and controlled by utilizing reconfigurable intelligent surfaces (RISs) to leverage their full potential. In this work, we first provide an assessment of the use of the THz band for ISLs, and quantify the impact of misalignment fading on error performance. Then, in order to compensate for the high path loss associated with high carrier frequencies, and to further improve the signal-to-noise ratio (SNR), we propose the use of RISs mounted on neighboring satellites to enable signal propagation. Based on a mathematical analysis of the problem, we present the error rate expressions for RIS-assisted ISLs with misalignment fading. Also, numerical results show that RIS can leverage the error rate performance and achievable capacity of THz ISLs

Robust and Fast Automatic Modulation Classification with CNN under Multipath Fading Channels

Automatic modulation classification (AMC) has been studied for more than a quarter of a century; however, it has been difficult to design a classifier that operates successfully under changing multipath fading conditions and other impairments. Recently, deep learning (DL)-based methods are adopted by AMC systems and major improvements are reported. In this paper, a novel convolutional neural network (CNN) classifier model is proposed to classify modulation classes in terms of their families, i.e., types. The proposed classifier is robust against realistic wireless channel impairments and in relation to that when the data sets that are utilized for testing and evaluating the proposed methods are considered, it is seen that RadioML2016.10a is the main dataset utilized for testing and evaluation of the proposed methods. However, the channel effects incorporated in this dataset and some others may lack the appropriate modeling of the real-world conditions since it only considers two distributions for channel models for a single tap configuration. Therefore, in this paper, a more comprehensive dataset, named as HisarMod2019.1, is also introduced, considering real-life applicability. HisarMod2019.1 includes 26 modulation classes passing through the channels with 5 different fading types and several numbers of taps for classification. It is shown that the proposed model performs better than the existing models in terms of both accuracy and training time under more realistic conditions. Even more, surpassed their performance when the RadioML2016.10a dataset is utilized

Identification of the concentration of iodopovidone pleurodesis in rats for the maximal effectiveness

Ozpolat, Berkant/0000-0002-6203-7306WOS: 000321798900027Background: This study aims to investigate the efficacy and safety of different doses of iodopovidone for pleurodesis and to evaluate the histopathological changes in thyroid tissue. Methods: Thirty-eight male Albino Wistar rats (260-320 g, 6-8 months old) included in this experimental study were randomly divided into four groups. Groups 1, 2, and 3 were given 2 mL/kg intrapleural iodopovidone at concentrations of 1%, 2%, 4%, respectively, while group 4 was administered intrapleural saline. The surfaces were graded by macroscopic and microscopic examination on Day 30 and thyroid tissues were histopathologically examined. Results: Iodopovidone at concentrations of 2% and 4% resulted in significantly more adhesions and inflammatory response. Four percent iodopovidone produced nonsignificant microscopic changes in the contralateral visceral pleural surface. No vacuolization in thyroid tissue showing hyperthyroidism was observed in the groups. Conclusion: We suggest that 2% iodopovidone is enough for an effective and safe pleurodesis and the concentration of iodopovidone may be raised to 4% in unsuccessful cases. However, as the study was conducted on rats, it still remains to be elucidated that the similar results can be achieved in human studies

Aspergillus And Nocardia Coinfection In A Patient With Allogeneic Stem Cell Transplantation

In this report, we present a rare case of Aspergillus and Nocardia coinfection in a patient who underwent extensive immunosuppressive treatment due to graft versus host disease after allogeneic stem cell transplantation. We would like to emphasize the effect of targeted treatment on patient survival, and importance of collaboration between clinicians and laboratory professionals in providing early diagnosis even in rare infections.WoSScopu