Relay System Research Articles

Blockchain-Based Spectrum Sharing Algorithm for UAV-Assisted Relay System

Unmanned aerial vehicles (UAVs) are promising tools in mobile communication due to their flexibility. However, the rapid development of mobile communications further intensifies the challenge of spectrum scarcity, necessitating spectrum sharing with other systems. We suggest a Spectrum Sharing Algorithm for a UAV-Assisted Relay System. The utility function of secondary users (SUs) is defined by their communication rate, rewards from relay primary users (PUs), and spectrum leasing expenses. The utility function of PUs consists of their communication rate and revenue from spectrum leasing. We propose a joint optimization algorithm for the positioning and power allocation of UAVs, maximizing the frequency spectrum utilization rate of users. Spectrum trading between PUs and SUs is modeled as a Stackelberg game, and the problem is solved by using Lagrange multipliers and KKT conditions. To enhance the security of spectrum trading, a reputation-based spectrum sharing blockchain consensus algorithm is designed. We utilize Shamir’s secret sharing method to reduce computational complexity. Additionally, we design a smart contract to optimize the functionality of transaction transfers. The findings demonstrate that the proposed algorithm enhances the benefits for both participants in spectrum sharing, while safeguarding the security of spectrum transactions.

Redox Status as a Key Driver of Healthy Pancreatic Beta-Cells.

Redox status plays a multifaceted role in the intricate physiology and pathology of pancreatic beta-cells, the pivotal regulators of glucose homeostasis through insulin secretion. They are highly responsive to changes in metabolic cues where reactive oxygen species are part of it, all arising from nutritional intake. These molecules not only serve as crucial signaling intermediates for insulin secretion but also participate in the nuanced heterogeneity observed within the beta-cell population. A central aspect of beta-cell redox biology revolves around the localized production of hydrogen peroxide and the activity of NADPH oxidases which are tightly regulated and serve diverse physiological functions. Pancreatic beta-cells possess a remarkable array of antioxidant defense mechanisms although considered relatively modest compared to other cell types, are efficient in preserving redox balance within the cellular milieu. This intrinsic antioxidant machinery operates in concert with redox-sensitive signaling pathways, forming an elaborate redox relay system essential for beta-cell function and adaptation to changing metabolic demands. Perturbations in redox homeostasis can lead to oxidative stress exacerbating insulin secretion defect being a hallmark of type 2 diabetes. Understanding the interplay between redox signaling, oxidative stress, and beta-cell dysfunction is paramount for developing effective therapeutic strategies aimed at preserving beta-cell health and function in individuals with type 2 diabetes. Thus, unraveling the intricate complexities of beta-cell redox biology presents exciting avenues for advancing our understanding and treatment of metabolic disorders.

Highly sensitive protection scheme considering the PV operation control models

The integration of distributed generation (DG) based on inverters into power systems has increased significantly, necessitating a thorough understanding of its impact on fault analysis and the performance of distribution networks' protection mechanisms. This study addresses this issue by examining how various inverter management modes influence protective relay systems within IEEE 9-bus redial and mesh networks, CIGRE and IEEE 33-bus networks featuring Photovoltaic (PV) farms and Battery Energy Storage Systems (BESS), by IEEE1547–2018 and German grid code standards. By analyzing grid-connected scenarios with five distinct PV control modes, the research introduces a novel protection methodology termed the Photovoltaic Overcurrent Relay (PVOCR). This method introduces a current-voltage characteristic to optimally coordinate Overcurrent Relays (OCRs), aiming to reduce their operational time and eliminate mis-coordination events. The proposed PVOCR is evaluated against standard inverse time, SOCR, and modern adaptive voltage, VOCR, relay schemes across various fault scenarios differing in type and location. Furthermore, the PVOCR scheme effectively operates across all PV inverter modes without experiencing miscoordination events, whereas the SOCR and VOCR schemes encountered such issues during the operation of Control 4. These results underscore the potential utility of the PVOCR methodology in enhancing the reliability and efficiency of protection systems in inverter-based DG networks.

Joint wireless energy transmission and dynamic power management for full-duplex relay system

The rapid deployment of fifth-generation (5G) mobile communication systems demands sustainable power solutions. This paper introduces a novel joint design for wireless energy transmission and dynamic power management in full-duplex relay systems, aiming to ensure a continuous power supply for relay nodes. Our approach integrates energy harvesting from RF signals and dynamic battery management, focusing on optimizing throughput via energy allocation and precoding design. Simulation results demonstrate that our scheme significantly outperforms conventional non-battery half-duplex schemes in system throughput. Notably, we observe performance increments in throughput compared to all mentioned traditional methods, highlighting the efficacy of our design in enhancing 5G network sustainability and efficiency. This innovative approach presents a promising solution for effective power management in next-generation mobile networks.

Proteomic analysis revealed gender-related differences in the skin mucus proteome of discus fish (Symphysodon haraldi) during the parental and non-parental care periods

The discus fish, Symphysodon spp., a South American cichlid, has a unique parental care behavior where fry bite on parental skin mucus after hatching. In this study, we used LC-MS/MS technique to compare the skin mucus proteome composition of male or female discus fish during parental and non-parental care periods. By multivariate statistical analysis, we found clear separations between different periods and between different sexes of mucus proteome. Compared with non-parental female fish, parental female fish had 283 up-regulated and 235 down-regulated expressed proteins. Compared with non-parental male fish, parental male fish had 169 up-regulated and 120 down-regulated expressed proteins. The differentially expressed proteins for male fish were enriched in sulfur relay system, mucin type O-glycan biosynthesis and antigen processing and presentation pathways, while those for female fish were enriched in sulfur relay system, steroid biosynthesis and complement and coagulation cascades pathways. During the parental care, both male and female discus showed an enhanced lipid metabolism, producing more phospholipids and cholesterol. The difference is that male discus had increased tricarboxylic acid cycle producing more energy during the parental care, while females produced more nucleotides especially guanylic acid. Our study could provide new insights into the understanding of the unique mucus supply behavior of discus fish based on proteomic change.

Eco-friendly Strategy for Producing Bio-based Silver Nanoparticles (AgNPs) Employing Sepioteuthis lessoniana ink, in Addition to Biological and Degradation of Dye Applications.

The squid, Sepioteuthis lessoniana, is a remarkable fishery product which is exported by many nations for use in industrial production or human consumption. This study focused on the synthesis of silver nanoparticles (AgNPs) from squid ink (SI) and its wide range of applications. The formation of the nanoparticles was confirmed through UV-Visible spectroscopy, FTIR, XRD, SEM with EDX, DLS, and zeta potential analysis. The results showed a strong absorbance peak at 407nm, the presence of various functional groups, a nanocrystalline structure with a crystalline size of 17.56nm, spherical-shaped particles with an average size of 76nm, and the presence of the highest % mass of Ag and uniformly dispersed particles, respectively. The bioactivity of the synthesized squid ink silver nanoparticles was analyzed through antibacterial, antioxidant, anticancer, and toxicity studies. The dye degradation assay was also analyzed as a means of wastewater treatment for different industrial dyes. The antibacterial activity showed the highest zone of inhibition of 24mm at a concentration of 100μg/ml against Escherichia coli, followed by other tested strains. The nitric oxide radical scavenging assay showed the highest antioxidant activity (92%) at a concentration of 100μg/ml. The cytotoxic ability of SI-AgNPs against the MDA-MB-231 breast cancer cell line revealed an IC50 value of 4.52μg/ml. The toxicity study revealed a dose and time-dependent activity with the LC50 value of 5.090 and 3.303mg/ml for 24 and 48h, respectively. The successful degradation of dyes by SI-AgNPs is attributed to the cooperative action of the electron relay system with Ag as a catalyst and SI as a catalytic support. These findings indicate that SI-AgNPs are a novel potential product that should be further studied to improve its pharmacological, biomedical, and environmental applications.

Exploration of Response Mechanisms in the Gills of Pacific Oyster (Crassostrea gigas) to Cadmium Exposure through Integrative Metabolomic and Transcriptomic Analyses.

Marine mollusks, including oysters, are highly tolerant to high levels of cadmium (Cd), but the molecular mechanisms underlying their molecular response to acute Cd exposure remain unclear. In this study, the Pacific oyster Crassostrea gigas was used as a biological model, exposed to acute Cd stress for 96 h. Transcriptomic analyses of their gills were performed, and metabolomic analyses further validated these results. In our study, a total of 111 differentially expressed metabolites (DEMs) and 2108 differentially expressed genes (DEGs) were identified under acute Cd exposure. Further analyses revealed alterations in key genes and metabolic pathways associated with heavy metal stress response. Cd exposure triggered physiological and metabolic responses in oysters, including enhanced oxidative stress and disturbances in energy metabolism, and these changes revealed the biological response of oysters to acute Cd stress. Moreover, oysters could effectively enhance the tolerance and detoxification ability to acute Cd exposure through activating ABC transporters, enhancing glutathione metabolism and sulfur relay system in gill cells, and regulating energy metabolism. This study reveals the molecular mechanism of acute Cd stress in oysters and explores the molecular mechanism of high tolerance to Cd in oysters by using combined metabolomics and transcriptome analysis.

Non-iterative sem-blind receiver for multi-way relay (MWR) systems

Non-iterative sem-blind receiver for multi-way relay (MWR) systems

Bayesian-optimized LSTM-DWT approach for reliable fault detection in MMC-based HVDC systems

As Europe integrates more renewable energy resources, notably offshore wind power, into its super meshed grid, the demand for reliable long-distance High Voltage Direct Current (HVDC) transmission systems has surged. This paper addresses the intricacies of HVDC systems built upon Modular Multi-Level Converters (MMCs), especially concerning the rapid rise of DC fault currents. We propose a novel fault identification and classification for DC transmission lines only by employing Long Short-Term Memory (LSTM) networks integrated with Discrete Wavelet Transform (DWT) for feature extraction. Our LSTM-based algorithm operates effectively under challenging environmental conditions, ensuring high fault resistance detection. A unique three-level relay system with multiple time windows (1 ms, 1.5 ms, and 2 ms) ensures accurate fault detection over large distances. Bayesian Optimization is employed for hyperparameter tuning, streamlining the model’s training process. The study shows that our proposed framework exhibits 100% resilience against external faults and disturbances, achieving an average recognition accuracy rate of 99.04% in diverse testing scenarios. Unlike traditional schemes that rely on multiple manual thresholds, our approach utilizes a single intelligently tuned model to detect faults up to 480 ohms, enhancing the efficiency and robustness of DC grid protection.

A hybrid physical and co-simulation modern adaptive power protection testbed for testing the resilience of smart grids under cyber-physical threats

Power protection systems play a critical role in ensuring the safe and reliable operation of modern power grids. With the increasing complexity of grid topologies and the integration of Distributed Energy Resources (DERs), traditional protection schemes face challenges in maintaining effective coordination among relay systems. This paper presents a new adaptive Overcurrent Relay (OCR) protection and investigates the resilience of different traditional and new adaptive OCR protection schemes against various cyber-physical threats in a smart grid environment. Key contributions include the implementation of a novel adaptive protection scheme designed to dynamically adjust OCR settings based on real-time grid conditions, improving flexibility and responsiveness in managing grid variations induced by DER integration and operational changes. The proposed scheme is validated and implemented using the Multifunction Protection Relay SIEMENS 7SJ62, following to the programming standards of IEC 61131–3, ensuring the reliability and practical applicability of the adaptive OCR scheme in real-world scenarios. Additionally, a dedicated testbed is developed to simulate real-time cyber-physical interactions, incorporating hardware components such as the SIEMENS 7SJ62 and OMICRON-256 test device, along with high-performance computers and communication networks to facilitate comprehensive evaluations of adaptive OCR schemes under varying operational conditions. The study also examines the implications of real-time cyber-attacks on power system operations and the effectiveness of adaptive OCR protection schemes, addressing cybersecurity concerns and proposing mitigation strategies to the system resilience.

Design and construction of wireless water level control system with motor protector

This research work presents the design and construction of a micro-controller-based wireless water level control system. The need to bring a solution to the problem of water shortage in various places by eliminating one of the culprit; waste of water during pumping and dispensing into overhead thanks, calls for an automated control system which puts into consideration, means of avoiding mechanical tears and wears that arises with the use of robes as water level sensor, through the incorporation of wireless water level sensor in place of robes in sensing the water level in the modeled tank. To solve this problem, circuit analysis and design, of the five main sub-circuitry units, this includes: power supply unit, logic and switching circuitry unit, relay unit, LCD display unit was carried out using ultrasonic water level sensor, AT89S51 microcontroller, LCD module relay circuitry system and a few discrete components. The design of the controller in this scenario is not just cost effective but helps in avoiding mechanical tears and wears that arises with the use of robes as water level sensor, by providing an improvement on existing water level control system through the incorporation of wireless water level sensor in place of robes in sensing the water level in the modeled tank.

Demonstrating autonomous controls on hardware test beds is a necessity for successful missions to Mars and beyond

NASA and the Department of Defense are planning for a mission to Mars in the 2030s–2040s using nuclear thermal propulsion (NTP). NTP uses a nuclear reactor to heat flowing hydrogen and create thrust. A serious concern for crewed and uncrewed missions to Mars is the loss of reactor control. The reactor startup and initial rocket impulse are initiated in cislunar or near-earth orbital regions; therefore, radio communications between ground control and the NTP engine should occur in real time. However, radio communications can take more than 20 min, depending on planet positions, to reach Mars orbiters from ground control. To address this delay, local autonomous controls are implemented onboard the NTP engine to ensure acceptable operation. However, autonomous controls have not been demonstrated or implemented in research or power reactor contexts because of safety and reliability concerns. To enable autonomous controls development, demonstration, and validation, Oak Ridge National Laboratory has created a nonnuclear hardware-in-the-loop test bed. Sensors throughout the test bed relay system status and hardware response to the user control algorithm, including measurements of temperature, flow, pressure of a loop, control drum position, and drum speed. This paper discusses the development of this facility and user accessibility.

Enhancing payload capacity to low earth orbit via a relay solution trajectory with laser-powered vehicles

ABSTRACT Low Earth Orbit (LEO) stands as the primary access point for deep space exploration endeavors, encompassing a variety of space missions such as communication satellites, Earth observation platforms, and scientific research missions. In light of the expanding scope of human activities in space, the cost associated with accessing LEO has emerged as a critical focal point for spacecraft designers. Within the spectrum of proposed solutions, laser-powered vehicle has emerged as a viable avenue toward achieving cost-effective launch options. In order to significantly augment the payload capacity of laser-powered launch vehicles destined for LEO, this study introduced a novel Relay Solution Trajectory Flight Scheme. Central to this scheme was the implementation of a relay mirror system affixed to a satellite, which served to stabilize the incident angle of the laser beam directed toward the laser-powered vehicle, thereby ensuring continuous alignment between the laser beam and the vehicle’s axis throughout the duration of the flight. Following the development of comprehensive structural, propulsive, aerodynamic, and trajectory models tailored for the laser-powered vehicle, an optimization of its flight trajectory was conducted, comparing this innovative strategy with two conventional flight strategies. The outcomes of this analysis showcased a notable enhancement of 269.29% in payload capacity compared to conventional strategies that lacked a relay satellite system, within a designated 400 km LEO flight scenario. This endeavor underscored the transformative potential of advanced relay systems in reshaping payload delivery mechanisms and elevating mission feasibility levels, notwithstanding the intricate coordination challenges posed by intricate satellite systems.

Application of saturated core transformer as inrush current limiter

An inrush current is a transient current that results from a sudden change in the exciting voltage across a transformer's windings. Reducing the inrush current of transformers is desirable due to mechanical stresses and negligent operation of protective relay systems such as differential relays. This paper investigates the application of a saturated-core transformer as an inrush current limiter (ICL). Analytical methods of inrush current and its electromagnetic forces on transformer windings with and without application of proposed ICL are presented. Also, the core saturation of the ICL and transformer, in addition to the voltage drop on the ICL in transient and steady states, are investigated. A single-phase transformer is modeled in two dimensions (2-D), and the forces due to inrush current are calculated by the finite element method (FEM) in Maxwell software. The radial and axial force distributions of transformer windings with and without the ICL are investigated. The results show the capability of ICL to limit the transformer inrush current and reduction of its electromagnetic forces. Our simulations demonstrate a significant reduction in inrush current (75 %) using the proposed Inrush Current Limiter (ICL). Additionally, the ICL effectively mitigates electromagnetic forces within the transformer. Compared to a scenario without ICL, the ICL reduces radial forces by 80 % and axial forces by a substantial 90 %. These findings suggest that the ICL offers a promising solution for mitigating both inrush current and the associated electromagnetic forces in power transformers.

INCREASING THE RELIABILITY OF THE SYSTEM OF AUTOMATIC VOLTAGE REGULATION OF LOW-VOLTAGE CIRCUITS OF ELECTRICAL DIRECT CURRENT MOVEMENT COMPONENTS

Purpose. The purpose of this work is the analysis of possible directions for improving the performance indicators of electric rolling stock of direct current railways. The work is devoted to the improvement of systems of automatic voltage regulation of low-voltage circuits where the power source is a direct current generator. The number of electric locomotives and electric trains of railways and their units, which have exhausted their service life, but will be in service for a long time, preserves the relevance of research into possible directions of modernization and the specifics of system operation. Methodology. The work uses the analysis and generalization of previously performed research. The methodological basis of the research is the mathematical apparatus of the theory of automatic control and the theory of reliability. The object of research is the process of functioning of low-voltage control circuits of electric rolling stock of direct current railways with direct current generators as an energy source. The subject of the study is a voltage regulator for own needs based on a modern element base. Findings. A variant of the system of automatic voltage regulation of low-voltage circuits with generator power sources for electric rolling stock of direct current is offered. The basis of the system is the voltage regulation node, which in the existing structure is made on the basis of a carbon vibration regulator on a strip. As an alternative, a system based on operational amplifiers and the use of proportional or proportional-integral laws of the regulator in the structure is proposed. Modeling of dynamic processes indicates the structural stability of the system and qualitative transition processes. A comparison of the no-failure indicators of the nodes indicates a possible increase in terms between services and cost savings. The comparison is made for systems that are in operation for a long time and those that are offered. Originality. It is proposed to implement the node of the system of automatic voltage regulation on a modern elemental basis, which allows to improve the reliability of the system and implement a small, economical, modernization of rolling stock of railways with an exhausted service life. Practical value. The obtained results can be used by enterprises that carry out major repairs of electric trains and direct current electric locomotives with extended service life. The implementation of the proposed units makes it possible to replace existing contact-based relay systems with fast contact wear, frequent maintenance and debugging. As a result, new units can be transferred to service during current repairs due to the introduction of non-contact systems and increase the probability of trouble-free operation and use the personnel who are always present in locomotive depots. This reduces the cost of maintenance due to the introduction of a modern element base and exclusion from the technological process of maintenance of existing units.

Sistem Otomasi Untuk Menyortir Barang Pada Ruang Produksi Menggunakan Scada dan PLC

The development of the industrial revolution is progressing. Especially on production performance or machine parts. Industrial revolution 4.0 uses the internet and digitalization. So there are lots of new innovations. In a large-scale company, of course there are many tools and machines that need to be regulated whether they are on or not with regular supervision. With regular supervision, it is impossible for human workers to check one by one, thereby wasting time and reducing production levels. Therefore, it is necessary to develop a control system using PLC and HMI (Human Machine Interface) as the brain or control center for the company. In the industrial sector, PLC (Programmable Logic Controller) is an important factor in the operation of automatic machines in factories replacing relay control systems. So that PLC as a control system in the industrial sector can move machines according to needs. One part of the industry is the production room. The production room is the part where there are manufacturing materials or goods up to packaging. This research aims to design and implement a PLC (Programmable Logic Controller) and SCADA by adding sensors and actuators as output. The method used is a rule base system, the system runs according to a predetermined sequence and flow. The results of this research are the PLC, the SHT 20 temperature and humidity sensor can produce temperature and humidity values, the capacitive photosensor can detect items with 35 trials accurately but the distance is limited to only 27cm, the proximity sensor can only detect metal objects by attaching to the sensor and The actuator in the form of a stepper motor can run according to the commands given and is well integrated into the HMI (Human Machine Interface).

Intelligent Reflecting Surface Assisted Full-Duplex Relay Systems: Deployment Design and Beamforming Optimization

Intelligent Reflecting Surface Assisted Full-Duplex Relay Systems: Deployment Design and Beamforming Optimization

Mechanism of PARP1 Elongation Reaction Revealed by Molecular Modeling

Poly(ADP-ribose) polymerase 1 (PARP1) plays a major role in the DNA damage repair and transcriptional regulation, and is targeted by a number of clinical inhibitors. Despite this, catalytic mechanism of PARP1 remains largely underexplored because of the complex substrate/product structure. Using molecular modeling and metadynamics simulations we have described in detail elongation of poly(ADP-ribose) chain in the PARP1 active site. It was shown that elongation reaction proceeds via the SN1-like mechanism involving formation of the intermediate furanosyl oxocarbenium ion. Intriguingly, nucleophilic 2′A-OH group of the acceptor substrate can be activated by the general base Glu988 not directly but through the proton relay system including the adjacent 3′A-OH group.

Australian East-West Radio Relay System Revisited: Thermal Design of Repeater Shelters

The Journal revisits two historic papers from 1971 covering the thermal design and environmental controls in repeater shelters of the Australian East-West radio relay system from Northam in Western Australia to Port Pirie in South Australia.

Creation of a Mathematical Model of a Stationary Rail Circuit in the Form of a Finite Discrete Automaton

Purpose. Ensuring the safety of train traffic is a mandatory task in the development of technical equipment of railway transport in Ukraine. To diagnose and verify the performance of such systems, simulation models of overhead devices, in particular, the rail circle, are used. The most commonly used models are in the form of differential equations and in operator form. Unfortunately, they are not fully suitable for solving this problem. In this regard, there is a need to create a mathematical model that is easier to integrate for checking both relay electrical interlocking and microprocessor-based interlocking systems. Methodology. To achieve this goal, the authors proposed to create a mathematical model in the form of a finite discrete automaton. This paper considers the creation of a model of a station rail circuit as a directed graph. During the creation of the model, the input and output values of the model and the states are determined. The tables of inputs and outputs of the automaton are constructed, sequential expressions for the abstract model of the automaton are created, and their minimization is performed. The states of the automaton are coded using trigger circuits. Findings. In the course of the research, a mathematical model of the rail circle in the form of a Moore model finite automaton was created, and its performance was tested in the Proteus software environment. The developed model allows to simulate the operation of a stationary rail circuit at the level of abstraction, which operates with binary signals. This makes it possible to simplify the coordination of the model with microprocessor-based centralization software. In general, it is now possible to more effectively check the performance of microprocessor-based interlocking systems at the design and commissioning stages. Originality. The developed mathematical model makes it possible to determine the response of the microprocessor-based centralization software to the behavior of the rail circuit in various, in particular atypical, operating modes, as well as to determine the response of the station electrical centralization system to individual failures and to the occurrence of several failures simultaneously. Practical value. The proposed mathematical model can be used both to check the operation of microprocessor-based centralization systems at the design and implementation stages and for relay centralization systems when developing diagnostic complexes for monitoring their performance.