Study of the Harmonic Analysis and Energy Transmission Mechanism of the Frequency Conversion Transformer

Since the transmission distance of submarine cable transmission is inversely proportional to the input frequency, to solve the problem of large losses in the transmission process of offshore wind power, this paper proposes a three-frequency transformer which enables the output of 50 Hz at the input of 50/3 Hz excitation. In this paper, the magnetic flux of a three-dimensional wound core transformer is analytically modeled, the existing condition of magnetic flux harmonics of a three-dimensional wound core transformer is analyzed, the distribution of harmonic content in magnetic flux is obtained, and the principle of realizing frequency conversion is expounded. Secondly, the finite element analysis of the frequency converter is carried out. Finally, a prototype of a frequency transformer is made and tested to verify the correctness of the proposed scheme.

Short-wave infrared continuous-variable quantum key distribution over satellite-to-submarine channels

The trans-media transmission of quantum pulse is one of means of free-space transmission which can be applied in continuous-variable quantum key distribution (CVQKD) system. In traditional implementations for atmospheric channels, the 1500-to-1600-nm pulse is regarded as an ideal quantum pulse carrier. Whereas, the underwater transmission of this pulses tends to suffer from severe attenuation, which inevitably deteriorates the security of the whole CVQKD system. In this paper, we propose an alternative scheme for implementations of CVQKD over satellite-to-submarine channels. We estimate the parameters of the trans-media channels, involving atmosphere, sea surface and seawater and find that the short-wave infrared performs well in the above channels. The 450 nm pulse is used for generations of quantum signal carriers to accomplish quantum communications through atmosphere, sea surface and seawater channels. Numerical simulations show that the proposed scheme can achieve the transmission distance of 600 km. In addition, we demonstrate that non-Gaussian operations can further lengthen its maximal transmission distance, which contributes to the establishment of practical global quantum networks.

A Study on the Impact of Distance-Based Value Loss on Transmission Network Power Flow Using Synthetic Networks

This paper presents a methodology for rapid generation of synthetic transmission networks and uses it to investigate how a transmission distance-based value loss affects the overall grid power flow. The networks are created with a graph theory-based method and compared to existing energy systems. The power production is located on these synthetic networks by solving a facility location optimization problem with variable distance-based value losses. Next, AC power flow is computed for a snapshot of each network using the Newton–Raphson method and the transmission grid power flow is analyzed. The presented method enables rapid analysis of several grid topologies and offers a way to compare the effects of production incentives and renewable energy policies in different network conditions.

Optimization for Compact and High Output LED-Based Optical Wireless Power Transmission System

Optical wireless power transmission (OWPT) is a technology that supplies energy remotely. Due to the great advantages of long transmission distances, high directionality, no electromagnetic interference noise, and loose safety regulations, light emitting diode (LED) based OWPT systems become appropriate candidates for powering various applications, especially for the Internet of things (IoT). In this paper, improved LED-OWPT systems are proposed based on a collimation scheme for optimizing the system dimension and output. In a single LED configuration, the system dimension is compressed by 46% while the high transmission efficiency is maintained. As for the LED-array system, the dimension is compressed by 56%, and the output is enhanced by 40%. In the experiment, a high electricity output of 532 mW is achieved at 1 m transmission distance. In addition, the effect of misalignment between LED and lens and the potential of long-distance transmission are clarified in the LED-array OWPT system.

Researching, building the routing algorithm in Zigbee networks

Zigbee wireless network built on IEEE 802.15.4 standard is becoming one of the most popular wireless networks in modern IoT devices. One of the disadvantages of Zigbee networks is the short transmission distance between devices. This paper focuses on researching and comparing routing algorithms in Zigbee networks, thereby building the optimal routing algorithm in the existing system. The paper’s objective is to form the basis for making Zigbee tree and mesh networks, which improves the transmission distance for Zigbee networks better than the star network.

Eavesdropping Vulnerability and Countermeasure in Infrared Communication for IoT Devices

Infrared (IR) communication is one of the wireless communication methods mainly used to manipulate consumer electronics devices. Traditional IR devices support only simple operations such as changing TV channels. These days, consumer electronic devices such as smart TV are connected to the internet with the introduction of IoT. Thus, the user’s sensitive information such as credit card number and/or personal information could be entered with the IR remote. This situation raises a new problem. Since TV and the set-top box are visual media, these devices can be used to control and/or monitor other IoT devices at home. Therefore, personal information can be exposed to eavesdroppers. In this paper, we experimented with the IR devices’ reception sensitivity using remotes. These experiments were performed to measure the IR reception sensitivity in terms of distance and position between the device and the remote. According to our experiments, the transmission distance of the IR remote signal is more than 20 m. The experiments also revealed that curtains do not block infrared rays. Consequently, eavesdropping is possible to steal the user’s sensitive information. This paper proposes a simple, practical, and cost-effective countermeasure against eavesdropping, which does not impose any burden on users. Basically, encryption is used to prevent the eavesdropping. The encryption key is created by recycling a timer inside the microcontroller typically integrated in a remote. The key is regenerated whenever the power button on a remote is pressed, providing the limited lifecycle of the key. The evaluation indicates that the XOR-based encryption is practical and effective in terms of the processing time and cost.

A Reliable and Efficient Tracking System Based on Deep Learning for Monitoring the Spread of COVID-19 in Closed Areas

Since 2020, the world is still facing a global economic and health crisis due to the COVID-19 pandemic. One approach to fighting this global crisis is to track COVID-19 cases by wireless technologies, which requires receiving reliable, efficient, and accurate data. Consequently, this article proposes a model based on Lagrange optimization and a distributed deep learning model to assure that all required data for tracking any suspected COVID-19 patient is received efficiently and reliably. Finding the optimum location of the Radio Frequency Identifier (RFID) reader relevant to the base station results in the reliable transmission of data. The proposed deep learning model, developed using the one-dimensional convolutional neural network and a fully connected network, resulted in lower mean absolute squared errors when compared to state-of-the-art regression benchmarks. The proposed model based on Lagrange optimization and deep learning algorithms is evaluated when changing different network parameters, such as requiring signal-to-interference-plus-noise-ratio, reader transmission power, and the required system quality-of-service. The analysis of the obtained results, which indicates the appropriate transmission distance between an RFID reader and a base station, shows the effectiveness and the accuracy of the proposed approach, which leads to an easy and efficient tracking system.

Spatiotemporal NF-κB dynamics encodes the position, amplitude and duration of local immune inputs

Infected cells communicate through secreted signaling molecules like cytokines, which inform nearby cells about the type, severity and location of pathogens. How differences in cytokine secretion affect inflammatory signaling over space and time, and how responding cells decode information from propagating cytokine signals are not understood. By computationally and experimentally studying NF-κB dynamics in co-cultures of signal sending cells (macrophages) and receiving cells (fibroblasts), we found that cytokine signals are transmitted by wave-like propagation of NF-κB activity and create well-defined cellular activation zones in a responding cell population. Remarkably, NF-κB dynamics in responding cells can simultaneously encode information about cytokine dose, duration, and distance to the cytokine source. Spatially-resolved transcriptional analysis revealed that responding cells transmit local cytokine information to distance specific pro-inflammatory gene expression patterns, creating gene expression zones in the population. Despite single-cell variability, the size and duration of the signaling zone is tightly controlled by the macrophage cytokine secretion profile. Our results highlight how macrophages tune their cytokine secretion dynamics to control signal transmission distance, and how NF-κB interprets these signals to coordinate inflammatory response in space and time.

Transmission Mechanism of Stock Price Fluctuation in the Rare Earth Industry Chain

The transmission of stock price fluctuations of listed companies in the rare earth industry has complex characteristics. Mastering its transmission law is of great meaning to understand the relationship between the upstream and downstream of the rare earth industry chain and market investment. This article uses the time series of daily closing prices of stocks in the global rare earth industry chain in the past ten years as the research object. The Granger causality test and complex network theory were used to construct the risk transmission network of the industrial chain. We have identified the key stocks in the network of stock price fluctuation in the rare earth industry chain and obtained the transmission path of stock price fluctuation. According to the results: (1) The stocks of Chinese and Japanese listed companies considerably influence the transmission of the stock price fluctuation in the rare earth industry chain. (2) The transmission distance of the stock price fluctuation of each network is relatively small, and the transmission speed is relatively fast. (3) The fluctuation of stock price in the rare earth industry chain is mainly transmitted from the upstream and midstream links to the midstream and downstream links.

Development of Low-Power Wide-Area Communication Gateway for Power Data Transmission

With the rapid development and maturity of communication technology, integrated computer technology and sensor technology, small sensors with sensing, computing and communication capabilities have begun to appear all over the world. The sensor network composed of these small sensors has received a lot of attention. This paper studies the low-power wide-area communication gateway for power data transmission. Based on the analysis of the energy consumption strategy of the power data transmission process, the low-power wide-area communication gateway for power data transmission is developed, and the developed gateway was tested. According to the peer test results of the gateway, the packet loss rate of the gateway within 100m is relatively good. Therefore, when arranging network nodes, try to control the transmission distance of the gateway within 100m. The energy consumption test shows that the energy consumption of the gateway is basically in an ideal state.