Base stations represent the main contributor to the energy consumption of a mobile cellular network. Since traffic load in mobile networks significantly varies during a working or weekend day, it is important to quantify the influence of these variations on the base station power consumption. Therefore, this paper investigates changes in the instantaneous power consumption of GSM (Global System for Mobile Communications) and UMTS (Universal Mobile Telecommunications System) base stations according to their respective traffic load. The real data in terms of the power consumption and traffic load have been obtained from continuous measurements performed on a fully operated base station site. Measurements show the existence of a direct relationship between base station traffic load and power consumption. According to this relationship, we develop a linear power consumption model for base stations of both technologies. This paper also gives an overview of the most important concepts which are being proposed to make cellular networks more energy-efficient.

https://www.mdpi.com/1424-8220/12/4/4281/pdf

Measurements and Modelling of Base Station Power Consumption under Real Traffic Loads

The nonlocal means algorithm is a noise attenuation filter that was originally developed for the purposes of image denoising. This algorithm denoises each sample or pixel within an image by utilizing other similar samples or pixels regardless of their spatial proximity, making the process nonlocal. Such a technique places no assumptions on the data except that structures within the data contain a degree of redundancy. Because this is generally true for reflection seismic data, we propose to adopt the nonlocal means algorithm to attenuate random noise in seismic data. Tests with synthetic and real data sets demonstrate that the nonlocal means algorithm does not smear seismic energy across sharp discontinuities or curved events when compared to seismic denoising methods such as f-x deconvolution.

Denoising seismic data using the nonlocal means algorithm

Modern industry 4.0 applications are shifting towards decentralized automation of computing and cyber-physical systems (CPS), which necessitates building a robust, secure, and efficient system that performs complex interactions with other physical processes. To handle complex interactions in CPS, trust and consensus among various stakeholders is a prime concern. In a similar direction, consensus algorithms in blockchain have evolved over the years that focus on building smart, robust, and secure CPS. Thus, it is imperative to understand the key components, functional characteristics, and architecture of different consensus algorithms used in CPS. Many consensus algorithms exist in the literature with a specified set of functionalities, performance, and computing services. Motivated from these facts, in this survey, we present a comprehensive analysis of existing state-of-the-art consensus mechanisms and highlight their strength and weaknesses in decentralized CPS applications. In the first part, we present the scope of the proposed survey and identify gaps in the existing surveys. Secondly, we present the review method and objectives of the proposed survey based on research questions that address the gaps in existing studies. Then, we present a solution taxonomy of decentralized consensus mechanisms for various CPS applications. Then, open issues and challenges are also discussed in deploying various consensus mechanisms in the CPS with their merits and demerits. The proposed survey will act as a road-map for blockchain developers and researchers to evaluate and design future consensus mechanisms, which helps to build an efficient CPS for industry 4.0 stakeholders.

/pdf/a-survey-on-decentralized-consensus-mechanisms-for-cyber-22y29ipx2u.pdf

A Survey on Decentralized Consensus Mechanisms for Cyber Physical Systems

Given the ongoing transition towards a more decentralised and adaptive energy system, the potential of blockchain-enabled smart contracts for the energy sector is being increasingly recognised. Due to their self-executing, customisable and tamper-proof nature, they are seen as a key technology for enabling the transition to a more efficient, transparent and transactive energy market. The applications of smart contracts include coordination of smart electric vehicle charging, automated demand-side response, peer-to-peer energy trading and allocation of the control duties amongst the network operators. Nevertheless, their use in the energy sector is still in its early stages as there are many open challenges related to security, privacy, scalability and billing. In this paper, we systematically review 178 peer-reviewed publications and 13 innovation projects, providing a thorough analysis of the strengths and weaknesses of smart contracts used in the energy sector. This work offers a broad perspective on the opportunities and challenges that stakeholders using this technology face, in both current and emergent markets, such as peer-to-peer energy trading platforms. To provide a roadmap for researchers and practitioners interested in the technology, we propose a systematic model of the smart contracting process, by developing a novel 6-layer architecture, as well as presenting a sample energy contract in pseudocode form and as open-source code. Our analysis focuses on the two mainstream application areas we identify for smart contract use in this area: energy and flexibility trading, and distributed control. The paper concludes with a comprehensive, critical discussion of the advantages and challenges that must be addressed in the area of smart contracts and blockchains in energy, and a set of recommendations that researchers and developers should consider when applying smart contracts to energy system settings. 

https://doi.org/10.1016/j.rser.2021.112013

Smart contracts in energy systems: A systematic review of fundamental approaches and implementations

In this paper we create a modeling scenario which includes an airborne imaging radar platform, receiving platform and an electronic countermeasure (ECM) platform whose goal is to introduce false target images. We also assume a high-resolution stripmap SAR model operating with several common types of UWB signals, as well as the newly proposed OFDM radar waveforms. OFDM-coded radar signals possess a viable quality of high pulse diversity potential, which can provide for robust performance in various jamming scenarios. In this paper, a method of jamming known as dasiadeceptionpsila is considered and a jammer model which aspires to generate false targets using intercepted radar signals is used. Two approaches to creating a radar signal by the jammer are considered: instantaneous frequency (IF) estimator and digital RF memory (DRFM)-based reproducer. In both cases, the jammer aims to create a copy of a valid target image - but located elsewhere in the observed target scene - via resending the radar signal at certain time intervals. Radar imaging simulation based on backprojection algorithm in presence of a deception jammer is performed for the cases of linear frequency modulated (LFM), short-pulse Gaussian, frequency-hopped (FH) and OFDM ultrawideband waveforms. The comparisons in ECCM performance of these signals are made based on the analysis of simulated imagery.

Deception jamming modeling in radar sensor networks

this paper focuses on the performance evaluation of consensus algorithms used in a blockchain system for Internet of Things (IoT). In such systems the time necessary to achieve consensus should be small. Three most used consensus algorithms (modified proof of work, practical byzantine fault tolerance and binary consensus) are evaluated in different situations – type of motes, number of nodes participating in consensus algorithm and radio propagation model. An integrated solution is proposed to adapt an IoT node to different consensus algorithm. The simulations in Contiki IoT operating system show good performance (time to achieve consensus less than seconds)

Blockchain and Consensus Algorithms in Internet of Things

The paper has the purpose to evaluate the performance of the lightweight TCP/IP protocol stack using the digital signal processor Blackfin BF537. The applications of such embedded system are in sensor networking, voice over IP (VoIP) communications and process control in industrial environments. The performance of LwIP stack has been evaluated using the evaluation board EZ-KIT. In this paper we demonstrated that the LwIP stack has good performance, comparable with the TCP/IP stack implementation in operating systems like Linux or Windows. Furthermore, a framework for developing embedded networking applications is provided.

LwIP stack protocol for embedded sensors network

The paper presents a wireless communication system that involved the frequency hopping spread spectrum technique M-ary frequency-shift keying (FH-MFSK) with M=2. The advantages of the FH are illustrated and compared with a direct sequence (DS) spread spectrum system from the point of view of interference suppression, multi-user interference suppression and implementation. An implementation with a low cost digital signal processor is presented. It is concluded that the FH spread spectrum technique is very attractive for wireless communication systems due its resistance to interference, multi-user access capability and simplicity of implementation with DSP microcontrollers.

Frequency hopping spread spectrum technique for wireless communication systems

The paper presents a simpler and efficient median filter used for removing the impulsive noise from the images. A real time implementation using a digital signal processor (DSP) is also presented. The improved median filter presented has better performance than the classical median filter with no very great additional computational effort.

Improved median filter for impulse noise removal

This paper presents a real time implementation of a noise removal system for audio signals. This system is based on the wavelet approach with level dependant threshold that provides a useful method for noise elimination in the signals. Experimental results show that this method removes noise significantly and the system operates in real time.

Sorin Zoican

Papers

Blockchain and Consensus Algorithms in Internet of Things

LwIP stack protocol for embedded sensors network

Frequency hopping spread spectrum technique for wireless communication systems

Improved median filter for impulse noise removal

Audio signals noise removal real time system