Long-range Power Research Articles

Research on the effect of different tungsten content liner materials on EFP forming

Abstract In response to the development of EFP warhead technology at home and abroad, as well as the requirements for long-range and high power in future battlefield environments for EFP warheads, a study was conducted on the influence of different tungsten content liner materials (pure Ta, Ta2.5W, Ta5W, Ta10W) on EFP formation. The results showed that the comprehensive performance of EFP formed by pure Ta, Ta5W, and Ta10W was slightly inferior to Ta2.5W, and Ta2.5W had higher strength and better flight stability, making it an ideal liner material.

DiagSWin: A multi-scale vision transformer with diagonal-shaped windows for object detection and segmentation

Recently, Vision Transformer and its variants have demonstrated remarkable performance on various computer vision tasks, thanks to its competence in capturing global visual dependencies through self-attention. However, global self-attention suffers from high computational cost due to quadratic computational overhead, especially for the high-resolution vision tasks (e.g., object detection and semantic segmentation). Many recent works have attempted to reduce the cost by applying fine-grained local attention, but these approaches cripple the long-range modeling power of the original self-attention mechanism. Furthermore, these approaches usually have similar receptive fields within each layer, thus limiting the ability of each self-attention layer to capture multi-scale features, resulting in performance degradation when handling images with objects of different scales. To address these issues, we develop the Diagonal-shaped Window (DiagSWin) attention mechanism for modeling attentions in diagonal regions at hybrid scales per attention layer. The key idea of DiagSWin attention is to inject multi-scale receptive field sizes into tokens: before computing the self-attention matrix, each token attends its closest surrounding tokens at fine granularity and the tokens far away at coarse granularity. This mechanism is able to effectively capture multi-scale context information while reducing computational complexity. With DiagSwin attention, we present a new variant of Vision Transformer models, called DiagSWin Transformers, and demonstrate their superiority in extensive experiments across various tasks. Specifically, the DiagSwin Transformer with a large size achieves 84.4% Top-1 accuracy and outperforms the SOTA CSWin Transformer on ImageNet with 40% fewer model size and computation cost. When employed as backbones, DiagSWin Transformers achieve significant improvements over the current SOTA modules. In addition, our DiagSWin-Base model yields 51.1 box mAP and 45.8 mask mAP on COCO for object detection and segmentation, and 52.3 mIoU on the ADE20K for semantic segmentation.

Long-Range Wireless Power Transfer for Moving Wireless IoT Devices

Wireless technologies are revolutionizing communications, with recent deployments, such as 5G, playing a key role in the future of the Internet of Things (IoT). Such progress is leading to an increasingly higher number of wirelessly connected devices. These require increased battery use and maintenance, consequently straining current powering solutions. Since most wireless systems rely on radiofrequency (RF) waves for communications and feature low-power technologies, it is increasingly feasible to develop and implement wireless power transfer solutions supported by RF. In this paper, a simultaneous wireless information and power transfer (SWIPT) solution targeting small mobile devices is presented. This solution uses beamforming to mitigate the path loss associated with the RF power propagation. It relies on an RF backscattering tracking algorithm to power moving devices. The feasibility to power wearable devices is demonstrated by tracking a walking individual (approximately 5 km/h) at a distance of 0.5 m while transferring a minimum of 6 dBm to a wearable device using 2 GHz RF signals. Simulations were used to determine the viability of such a solution to deliver useful power levels to a 1.2 × 1.4 m2 working area without exceeding specific absorption rate (SAR) limits.

Description and analysis of Sigfox received signal strength indicator dataset by using statistical techniques

Low power wide area network (LPWAN) technology has expanded and is essential in the development of applications for the internet of things (IoT). The Sigfox LPWAN network is characterized by its long-range coverage, low cost and power consumption. In this article, a set of 5174 values is analyzed, containing 1606 null RSSI data, obtained with the Sipy module and MicroPython, which provide a coverage map of several points with a resolution of 200 meters deployed in Quito–Ecuador. It is evaluated the type of distribution to which the set of network measurements is adjusted and an optimal 900 MHz propagation model in suburban environments is determined from the measurements obtained from the known base station. As a result, the lost values of RSSI were predicted using the inverse normal distribution method in the original values, observing that they conform to a logistic distribution. The data from the base station were subjected to a data augmentation algorithm designed in MATLAB, determining that the stanford university interim (SUI) model reduces the precision error in the trend of the curve by not presenting changes greater than 5 dB, achieving a precision of 97% with respect to the fit of the curve of the data.

LoRa based long-range traceable life jacket system design

It is recorded that around 100 people per year die due to fishing boat accidents, the majority of whom are small fishermen with vessels under 10 GT. LoRa is a license-free power-saving long-distance communication technology that can send data packets of up to 15 km in the ocean. The longrange power can be used to determine the location of fishermen when an accident occurs at sea. This research aims to implement and test the performance of LoRa Ebyte E22-400T30D for sending coordinate data on fishermen’s whereabouts in the form of life jackets. The performance observed is the relationship between the distance and the RSSI value obtained. The tests were performed until the furthest distance was reached. The test was carried out at Pangandaran Beach, and the receiver was placed at an altitude of 129 m toward the beach. The data will be displayed and stored on the Thinger.io website. The test results obtained with the furthest distance achieved were 12.983 km with a battery life of 5.99 hours. The RSSI value obtained tended to worsen with increasing distance. Apart from the distance, it was also found that obstructions in the form of trees could reduce the RSSI value.

Engineering perovskite solar cells for efficient wireless power transfer

Metal halide perovskites are a promising photovoltaic technology for energy harvesting due to their potential for low cost via high-speed manufacturing and their flexible light form factors offering high power per weight. This study presents an investigation of the energy harvesting performance of perovskite solar cells under monochromatic illumination via finite element simulations and experimental validation with high-efficiency double cation perovskite solar cells. Device performance across a broad range of illumination intensity is analyzed, providing insights into the mechanisms limiting energy harvesting in medium- and long-range wireless power transfer. The simulations also provide a guideline for compositional engineering of wide bandgap perovskites to improve the spectral match to efficient monochromatic sources. Based on these results, we show how perovskite solar cells can become a platform for efficient (>33%) medium-range wireless power transfer at the 5–50 m scale for power levels of 1 mW to 1 W.

Analysis and Experiment of Laser Energy Distribution of Laser Wireless Power Transmission Based on a Powersphere Receiver

Laser wireless power transmission (WPT) is one of the most important technologies in the field of long-range power transfer. This technique uses a laser as a transmission medium instead of conventional physical or electrical connections to perform WPT. It has the characteristics of long transmission distance and flexible operation. The existing laser wireless power transmission system uses photovoltaic cells as a receiver, which convert light into electricity. Due to the contradiction between the Gaussian distribution of laser and the uniform illumination requirements of photovoltaic cells, the laser wireless power transmission technology has problems such as low transmission efficiency and small output power. Therefore, understanding the energy distribution changes in the laser during transmission, especially the energy change after the laser is transmitted to each key device, and analyzing the influencing factors of the energy distribution state, are of great significance in improving the transmission efficiency and reducing the energy loss in the system. This article utilizes the optical software Lighttools as a tool to establish a laser wireless power transmission model based on a powersphere. This model is used to study the energy distribution changes in the laser as it passes through various components, and to analyze the corresponding influencing factors. To further validate the simulation results, an experimental platform was constructed using a semiconductor laser, beam expander, Fresnel lens, and powersphere as components. A beam quality analyzer was used to measure and analyze the laser energy distribution of each component except for the powersphere. The output voltage and current values of various regions of the powersphere were measured using a multimeter. The energy distribution of the powersphere was reflected based on the linear relationship between photo-generated current, voltage, and light intensity. The experimental results obtained were in good agreement with the simulation results. Simulations and experiments have shown that using a beam expander can reduce divergence angle and energy loss, while employing large-aperture focusing lens can enhance energy collection and output power, providing a basis for improving the efficiency of laser wireless power transfer.

Dynamic Parameter Allocation With Reinforcement Learning for LoRaWAN

LoRaWAN attracted lots of attention with its capacity for large device numbers, long-range and low power consumption. In order to simplify the transmission procedure, a pure Aloha protocol is implemented into its MAC layer. However, as the number of connected devices to the base station increases, the devices’ transmission parameters allocation becomes a vital issue related to network performance. This research contributes to the decentralized dynamic Spreading Factor (SF) allocation strategies during transmission by proposing STEPS, a Score Table based Evaluation and Parameters Surfing approach. STEPS is a reinforcement learning-based method that evaluates and changes the parameters based on probability and score tables. It provides a nondeterministic parameter selection method by updating the table while transmitting. Some variants of STEPS with different algorithms are proposed. Moreover, an estimation-based initialization is proposed to improve learning performance. Simulations and statistical tests are carried out with MULANE, a lightweight LoRaWAN Simulator developed in our previous work. The results show that the estimation has a high confidence level. Compared with the baseline methods, the proposed methods reduce energy consumption by 24-27% in different numbers of nodes. For bi-directional transmission, the proposed methods increase the 18% network throughput in a small number of nodes and 33% in a large number of nodes. Moreover, the proposed methods provide a framework of decentralized parameter allocation, which gives the extendability of this work.

Quantum criticality of a Z_{3}-symmetric spin chain with long-range interactions.

Based on large-scale density matrix renormalization group techniques, we investigate the critical behaviors of quantum three-state Potts chains with long-range interactions. Using fidelity susceptibility as an indicator, we obtain a complete phase diagram of the system. The results show that as the long-range interaction power α increases, the critical points f_{c}^{*} shift towards lower values. In addition, the critical threshold α_{c}(≈1.43) of the long-range interaction power is obtained for the first time by a nonperturbative numerical method. This indicates that the critical behavior of the system can be naturally divided into two distinct universality classes, namely the long-range (α<α_{c}) and short-range (α>α_{c}) universality classes, qualitatively consistent with the classical ϕ^{3} effective field theory. This work provides a useful reference for further research on phase transitions in quantum spin chains with long-range interaction.

TRANSMISSION LINE FAULT DETECTION SYSTEM

Transmission line is the most important part of the power system. Transmission lines a principal amount of power. The requirement of power and its allegiance has grown up exponentially over the modern era, and the major role of a transmission line is to transmit electric power from the source area to the distribution network. The exploded between limited production and a tremendous claim has grown the focus on minimizing power losses. Losses like transmission loss and also conjecture factors as like as physical losses to various technical losses, Another thing is the primary factor it has a reactive power and voltage deviation are momentous in the long-range transmission power line. In essentially, fault analysis is a very focusing issue in power system engineering to clear fault in short time and re-establish power system as quickly as possible on very minimum interruption. However, the fault detection that interrupts the transmission line is itself challenging task to investigate fault as well as improving the reliability of the system. The transmission line is susceptible given all parameters that connect the whole power system. This paper presents a review of transmission line fault detection.

TRANSMISSION LINE FAULT DETECTION SYSTEM

Transmission line is the most important part of the power system. Transmission lines a principal amount of power. The requirement of power and its allegiance has grown up exponentially over the modern era, and the major role of a transmission line is to transmit electric power from the source area to the distribution network. The exploded between limited production and a tremendous claim has grown the focus on minimizing power losses. Losses like transmission loss and also conjecture factors as like as physical losses to various technical losses, Another thing is the primary factor it has a reactive power and voltage deviation are momentous in the long-range transmission power line. In essentially, fault analysis is a very focusing issue in power system engineering to clear fault in short time and re-establish power system as quickly as possible on very minimum interruption. However, the fault detection that interrupts the transmission line is itself challenging task to investigate fault as well as improving the reliability of the system. The transmission line is susceptible given all parameters that connect the whole power system. This paper presents a review of transmission line fault detection.

Long-Range Wireless Power Drive Using Magnetic Extender

This article proposes and implements a long-range wireless power drive (WPD) system using a magnetic extender, which can be promisingly applied in underground pipeline transportations and in-pipe robots. Generally, the underground pipeline transportation networks usually rely on the power grid and control system to regulate the flow rate. Nonetheless, such wired pipeline networks mainly suffer from increasing the construction cost, maintenance difficulty, and system complexity. By using pulse frequency modulation, the development of the proposed long-range WPD enables a wireless pipeline network for flow rate regulation, which has the advantages of robust structure and reduced maintenance requirements. With the addition of a designed magnetic extender, the circuit network can offer an excellent fault tolerance capability for underground sensor-free WPD while maintaining a high transmission efficiency. Significantly, the use of a magnetic extender will cause no inconvenience thanks to its underground deployment. Accordingly, the system efficiency of a full-scale prototype can reach around 89.1% for the meter-range WPD. Theoretical analysis, computational simulation, and prototype experimentation are given to verify the feasibility of the proposed long-range WPD using a magnetic extender.

Long-Range Optical Wireless Information and Power Transfer

Simultaneous wireless information and power transfer (SWIPT) is a remarkable technology to support both the data and the energy transfer in the era of Internet of Things (IoT). In this article, we proposed a long-range optical wireless information and power transfer system utilizing retro-reflectors, a gain medium, a telescope internal modulator to form the resonant beam, achieving high-power and high-rate SWIPT. We adopt the transfer matrix, which can depict the beam modulated, resonator stability, transmission loss, and beam distribution. Then, we provide a model for energy harvesting and data receiving, which can evaluate the SWIPT performance. Numerical results illustrate that the proposed system can simultaneously supply 0–9 W electrical power and 18-bit/s/Hz spectral efficiency over 20-m distance.

Enabling an inter-operator roaming capability in LoRaWAN networks

LoRaWAN is a promising enabling technology for connected things. Nowadays, it is largely used in many application areas thanks to its relevant features such as long-range, low-cost, and low power consumption. However, as with all wireless technologies, mobility remains a major concern bringing end-devices out of their home operator coverage. In this paper, we investigate the inter-operator roaming capability in mobile scenarios. We proposed a novel LoRaWAN roaming scheme to enable inter-operator roaming based on DNS resolution and end-device context migration between networks. Moreover, we extended the LoRaWAN architecture while maintaining the integrity of the existing mechanisms and with a minimum prior configuration requirements. In order to validate our solution, we designed and implemented a test-bed platform integrating our extensions to Chirpstack. An extensive experimental study under various traffic loads demonstrates that the context migration delay perfectly fits the Class A LoRaWAN requirements. We also designed and implemented a LoRaWAN roaming emulator which states on the effectiveness of our roaming solution in terms of response time required for DNS resolution and end-device context migration, as well as CPU and memory utilization.

Long-range wireless optical power transfer system using an EDFA

A wireless optical power transfer (WOPT) system using an erbium-doped fiber amplifier as an optical power source is proposed to achieve long range, high power, and hazard-free power delivery in the air. The transmitter generates a wide band of amplified spontaneous emission around the central wavelength of 1550 nm. A wavelength division multiplexing (WDM) filter (λ=1552.25 nm) is deployed to obtain a safe narrowband beam illuminating the receiver units. A ball lens retroreflector reflects a small portion of the incident beam back to the transmitter, establishing a closed ring resonance loop. An improved safety mechanism is proposed to terminate the resonance when an obstacle blocks the transmitter-receiver line of sight. The measured incident power of 1 W decreases to 0.79 mW after the WDM filter is deployed which is well within defined maximum permissible exposure standards. For the demonstration of free-space transmission, transmitter-receiver separation is extended to 30 m. The experimental results show that a single-channel WOPT system provides an optical power of 400 mW with a channel linewidth of 1.027 nm over 30 m and an electrical power of 85 mW is acquired using a gallium antimonide photovoltaic.

A Fast-Speed GMPPT Method for PV Array Under Gaussian Laser Beam Condition in Wireless Power Transfer Application

The laser power transfer system is one of the most promising systems in the long-range wireless power transfer field. However, the low efficiency at photovoltaic (PV) receiver limits the performance of an implemented system due to the Gaussian laser beam. Since the irradiance profile of the Gaussian laser beam is not uniform, the PV array exhibits complex output characteristics with multiple peaks, leading that the conventional maximum power point tracking (MPPT) method is not acceptable either on tracking accuracy or on tracking speed. In this article, a simple and rapid voltage-location global MPPT (VL-GMPPT) method is proposed for PV array under Gaussian laser beam condition (GLBC) in terms of reducing the voltage searching range. In order to do so, the mathematical model of PV array's global maximum power point (GMPP) is developed under GLBC. Then, the VL-GMPPT method incorporates voltage-location mechanism to directly move the operating point to the vicinity of GMPP and employs IncCond method to accurately find the GMPP. The experimental and simulation results are shown to verify the proposed GMPPT method. It was found that the proposed method can reduce 90% of tracking time that is consumed by the conventional global searching method.

Design and optimisation of high‐efficient class‐F ULP‐PA using envelope tracking supply bias control for long‐range low power wireless local area network IEEE 802.11ah standard using 65 nm CMOS technology

This article presents the design and optimisation of a sub-1 GHz class-F ultra-low power (ULP) power amplifier (PA) in 65 nm Complementary Metal Oxide Semiconductor (CMOS) technology. An envelope tracking (ET) supply biasing technique is adopted to improve the efficiency of class-F PA. The ET consist of a pre-amp right before the detector in order to enhance the efficiency and save adequate amount of dc power consumption. The PA consists of two cascode cells terminated as class-F with gate-to-drain feedback in order to enhance linearity and limit any harmonic component from the input signal. The novel design consumes a dc power of 3.75 mW, power added efficiency of 37.1%, operating at 915–925 MHz unlicensed band and total saturated output power of 22 dBm including 14 dBm power gain at PA, which qualifies under long-range low power wireless personal area network IEEE 802.11ah standard. The inductor-less design for ET supply bias reduces the chip layout size to 0.13 mm2 only.

Computer simulation of long line with loss in steady harmonic mode at active load

Background: The implementation of projects to create long-range power systems requires the greatest possible study of not only the technical feasibility of long lines, but also the features of energy transmission along these lines. Such studies can be carried out in the field, using a physical experiment or using computer simulation. The first is limited by the complexity of the experiment, the lack of access to real measurements. Unlike a physical experiment, computer simulation is devoid of these problems: it makes it quite easy not only to model a long line, but also to study it under various operating modes. The practical significance of this work is the applicability of the proposed method in the educational process when students of energy specialties of transport universities perform research on lines with distributed parameters to solve subsequent problems in the development or development of new energy systems of great extent.&#x0D; Aim: Building a computer model of a long line and developing a method for studying various modes of its operation under various loads, including idling and short circuit.&#x0D; Methods: Computer modelling.&#x0D; Results: A computer model of a line with distributed parameters has been constructed, which allows one to study it under various modes.&#x0D; Conclusion: As part of the development of energy systems, the relevance of developing and modeling new methods for studying various modes in such circuits increases many times over. At the same time, newly developed methods should be applicable in the educational process. The article describes computer simulation and study of a long line under various active loads of the distribution of the effective value of the voltage along the line during its transmission, equal to half the wavelength (half-wave line). Research in this direction has not only scientific significance, but also practical, since it is possible to reasonably develop new models of long lines, as well as solve problems in the field of studying non-stationary (transient) operating modes of long lines.

Research on the output characteristics of laser wireless power transmission system with nonuniform laser irradiation

Laser wireless power transmission (LWPT), which can realize long-range power transmission, has been received widespread attention in recent years. The influence of high-power laser nonuniform irradiation on the output power and conversion efficiency of photocells has attracted much attention. This article conducted simulations and experiments on nonuniform irradiation with a constant power density and on nonuniform irradiation with constant incident power. The current I, voltage V, output power PL, conversion efficiency ηL, internal resistance R0, and maximum power point resistance RLmax of a 1 cm × 1 cm single-junction gallium arsenide photocell under nonuniform irradiation were studied. Under the condition of nonuniform irradiation with a constant laser power density, the conversion efficiency of the photocell remained constant, but R0 increased nonlinearly from 0.5 to 5 Ω. The ηL decreased from 45% to 5% when the load resistance is constant. Under the condition of nonuniform irradiation with constant laser power, the photoelectric conversion efficiency and R0 changed little, and the ηL remained about 45%, for it is not affected by nonuniform irradiation. The output characteristics of the photocells under uniform irradiation were also studied, and the results were consistent with the above conclusions. When the photocells with constant temperature were irradiated in-homogeneously, it was also revealed that the internal resistance increased and that the conversion efficiency decreased due to the irradiation power variation. The empirical formula was derived through circuit transformation and curve fitting.

Seeing Through the Walls with Wireless Technology: A Review

Background: Wireless technology has made a great impact on the whole world by providing us with 5G cellular to backscatter networking, from long-range wireless power to low-power wide-area networks. The ability to see through the walls via wireless signals has ushered in a new era. This technology has a wide range of applications, such as military, law enforcement, medicine, and games. Objective: This paper has concisely analyzed recent advances in the field of see-through-the-wall technology to improve a definitive knowledge of existing models and methodologies as well as provide recommendations for future directions. One of the most recent models is the Xaver ™ LR80, which is the first gadget that detects objects across a distance of more than 100 metres. Methodology: The dry lab technique for the comparison of existing models for frequency, power, model, detection ability, accuracy, localization feature, and applications has been used. Further comparison is based on the multipath effect. Their applications, the challenges that they need to face, and eventually suggestions for future work have been elaborated. Conclusion: In general, the paper outlines the current level of knowledge in the field of see-through the wall technology. It establishes a foundation for comprehending the issue by examining the findings of contemporary research in the field.