Art Image Compression Based on Lossless LZW Hashing Ciphering Algorithm

Color image compression is a good way to encode digital images by decreasing the number of bits wanted to supply the image. The main objective is to reduce storage space, reduce transportation costs and maintain good quality. In current research work, a simple effective methodology is proposed for the purpose of compressing color art digital images and obtaining a low bit rate by compressing the matrix resulting from the scalar quantization process (reducing the number of bits from 24 to 8 bits) using displacement coding and then compressing the remainder using the Mabel ZF algorithm Welch LZW. The proposed methodology maintains the quality of the reconstructed image. Macroscopic and quantitative experimental results on technical color images show that the proposed methodology gives reconstructed images with a high PSNR value compared to standard image compression techniques.

On instantaneous propagation of low-frequency signals in short transmission lines

One of the basic assumptions of physics is that information cannot be transferred more rapidly than light. If one equates information with data, then information transfer is a process in which data are transmitted between two remote locations. According to this basic principle, the transmission process should require an appropriate amount of time so that the distance between these locations divided by the needed time does not exceed the speed of light in a vacuum. However, it is technologically feasible to transmit a voice message, music, or any bit sequence at a low bit rate between locations separated by hundreds of meters, with almost no loss of time. Herein, we demonstrate that this behavior most likely does not contradict special relativity, and we explain this phenomenon based on a model of a superconducting cable.

On instantaneous propagation of low-frequency signals in short transmission lines

One of the basic assumptions of physics is that information cannot be transferred more rapidly than light. If one equates information with data, then information transfer is a process in which data are transmitted between two remote locations. According to this basic principle, the transmission process should require an appropriate amount of time so that the distance between these locations divided by the needed time does not exceed the speed of light in a vacuum. However, it is technologically feasible to transmit a voice message, music, or any bit sequence at a low bit rate between locations separated by hundreds of meters, with almost no loss of time. Herein, we demonstrate that this behavior most likely does not contradict special relativity, and we explain this phenomenon based on a model of a superconducting cable.

Locating Ships Using Time Reversal and Matrix Pencil Method by Their Underwater Acoustic Signals

This paper presents a technique, based on the matrix pencil method (MPM), for the compression of underwater acoustic signals produced by boat engines. The compressed signal, represented by its complex resonance expansion, is intended to be sent over a low-bit-rate wireless communication channel. We demonstrate that the method can provide data compression greater than 60%, ensuring a correlation greater than 93% between the reconstructed and the original signal, at a sampling frequency of 2.2 kHz. Once the signal was reconstituted, a localization process was carried out with the time reversal method (TR) using information from four different sensors in a simulation environment. This process sought to achieve the identification of the position of the ship using only passive sensors, considering two different sensor arrangements.

Development of a CubeSat Single Channel LoRa Receiver Module for Space-based IoT Application

CubeSat attracts many researchers due to its low production and deployment cost. One of the application is implemented in low data rate communication or machine to machine (M2M) with IoT devices in remote areas such as islands, forests, and mountains. In this study, a CubeSat receiver for IoT communication in remote areas has been developed and realized. A LoRa SX1276 chip is used for processing passband signals captured by the antenna. The device has a amplifier gain of 20.92 dB, 390 mW power consumption, and operating frequency of 923 MHz. The developed CubeSat is expected to provide a low bit rate of 5468.750 bps for SF 7 and 292.969 for SF 12 , the receiver serves as a concentrator for monitoring devices in rural areas.

Cloud-based platforms for LoRa internet of things: a survey

<span><span>Internet of Things</span> (IoT) establishes a smart communication system between the human being and the surrounding objects (or “things”) while using the internet as the backbone of this system. Cloud is the fundamental constituent of IoT. It offers important application services in numerous <span>application domains</span>. Indeed, many IoT cloud platforms are competing to provide appropriate and very specific IoT services. The LoRa platform in particular presents a long-range, low-bit rate, low-power, wireless telecommunication protocol for IoT. As such, end-devices make use of LoRa through a sole wireless hop in order to communicate to the gateway(s) that is (are) considered as relay messages and transparent bridges between these end-devices and an IoT cloud while connecting to the Internet. This article surveys the most used IoT <span>cloud platforms</span> suitable for the LoRa communication protocol through a deep and detailed study of previously published works related to this topic. Moreover, a comparison is made between these IoT cloud platforms according to their characteristics and application domains. The overall aim of the present paper is to provide researchers in the field with detailed knowledge concerning the IoT <span>cloud platforms appropriate to the LoRa communication system </span>including the advantages and drawbacks of each one of them.</span>