Deep Reinforcement Learning for Physical Layer Security Enhancement in Energy Harvesting Based Cognitive Radio Networks.

The paper studies the secrecy communication threatened by a single eavesdropper in Energy Harvesting (EH)-based cognitive radio networks, where both the Secure User (SU) and the jammer harvest, store, and utilize RF energy from the Primary Transmitter (PT). Our main goal is to optimize the time slots for energy harvesting and wireless communication for both the secure user as well as the jammer to maximize the long-term performance of secrecy communication. A multi-agent Deep Reinforcement Learning (DRL) method is proposed for solving the optimization of resource allocation and performance. Specifically, each sub-channel from the Secure Transmitter (ST) to the Secure Receiver (SR) link, along with the jammer to the eavesdropper link, is regarded as an agent, which is responsible for exploring optimal power allocation strategy while a time allocation network is established to obtain optimal EH time allocation strategy. Every agent dynamically interacts with the wireless communication environment. Simulation results demonstrate that the proposed DRL-based resource allocation method outperforms the existing schemes in terms of secrecy rate, convergence speed, and the average number of transition steps.

A Design of FPGA-Based Neural Network PID Controller for Motion Control System.

In the actual industrial production process, the method of adaptively tuning proportional-integral-derivative (PID) parameters online by neural network can adapt to different characteristics of different controlled objects better than the controller with PID. However, the commonly used microcontroller unit (MCU) cannot meet the application scenarios of real time and high reliability. Therefore, in this paper, a closed-loop motion control system based on BP neural network (BPNN) PID controller by using a Xilinx field programmable gate array (FPGA) solution is proposed. In the design of the controller, it is divided into several sub-modules according to the modular design idea. The forward propagation module is used to complete the forward propagation operation from the input layer to the output layer. The PID module implements the mapping of PID arithmetic to register transfer level (RTL) and is responsible for completing the output of control amount. The main state machine module generates enable signals that control the sequential execution of each sub-module. The error backpropagation and weight update module completes the update of the weights of each layer of the network. The peripheral modules of the control system are divided into two main parts. The speed measurement module completes the acquisition of the output pulse signal of the encoder and the measurement of the motor speed. The pulse width modulation (PWM) signal generation module generates PWM waves with different duty cycles to control the rotation speed of the motor. A co-simulation of Modelsim and Simulink is used to simulate and verify the system, and a test analysis is also performed on the development platform. The results show that the proposed system can realize the self-tuning of PID control parameters, and also has the characteristics of reliable performance, high real-time performance, and strong anti-interference. Compared with MCU, the convergence speed is far more than three orders of magnitude, which proves its superiority.

Multiband Spectrum Sensing and Power Allocation for aCognitive Radio-Enabled Smart Grid.

As part of an Internet of Things (IoT) framework, the Smart Grid (SG) relies on advanced communication technologies for efficient energy management and utilization. Cognitive Radio (CR), which allows Secondary Users (SUs) to opportunistically access and use the spectrum bands owned by Primary Users (PUs), is regarded as the key technology of the next-generation wireless communication. With the assistance of CR technology, the quality of communication in the SG could be improved. In this paper, based on a hybrid CR-enabled SG communication network, a new system architecture for multiband-CR-enabled SG communication is proposed. Then, some optimization mathematical models are also proposed to jointly find the optimal sensing time and the optimal power allocation strategy. By using convex optimization techniques, several optimal methods are proposed to maximize the data rate of multiband-CR-enabled SG while considering the minimum detection probabilities to the active PUs. Finally, simulations are presented to show the validity of the proposed methods.

Low Thermal Expansion Modulated by Off-Stoichiometric Effect in Nonstoichiometric Laves Phase Hf0.87Ta0.13Fe2+x Compounds.

Materials with a low coefficient of thermal expansion (CTE) are extremely demanded in many fields, varying from microelectronics to space technology. Here we report a novel method to achieve low CTE, which differs essentially from the conventional way that uses additives with negative thermal expansion (NTE) to compensate for the positive CTE of the matrix. The stoichiometric Hf0.87Ta0.13Fe2+x (x = 0) shows a giant NTE, which is gradually suppressed with increasing x and finally changed to near-zero thermal expansion (ZTE) at x ≈ 0.4. The excess Fe was suggested to form anti-site defects by occupying the 4f sites. As revealed by electron spin resonance (ESR) spectra, the weakened NTE is closely related to a slower ferromagnetic (FM) ordering process than observed at x = 0. In addition, the CTE can be further tuned by introducing an extra α-Fe phase to achieve a low CTE (e.g., 3.3 ppm/K for x = 1.0) with markedly enhanced mechanical properties, beneficial to applications.

Influence of Wolbachia infection on mitochondrial DNA variation in the genus Polytremis (Lepidoptera: Hesperiidae).

The maternally inherited obligate bacteria Wolbachia is known for infecting the reproductive tissues of a wide range of arthropods and can contribute to phylogenetically discordant patterns between mtDNA and nDNA. In this study, we tested for an association between mito-nuclear discordance in Polytremis and Wolbachia infection. Six of the 17 species of Polytremis were found to be infected with Wolbachia. Overall, 34% (70/204) of Polytremis specimens were Wolbachia positive and three strains of Wolbachia identified using a wsp marker were further characterized as six strains based on MLST markers. Wolbachia acquisition in Polytremis appears to occur mainly through horizontal transmission rather than codivergence based on comparison of the divergence times of Wolbachia and Polytremis species. At the intraspecific level, one of the Wolbachia infections (wNas1) is associated with reduced mtDNA polymorphism in the infected Polytremis population. At the interspecific level, there is one case of mito-nuclear discordance likely caused by introgression of P. fukia mtDNA into P. nascens driven by another Wolbachia strain (wNas3). Based on an absence of infected males, we suspect that one Wolbachia strain (wNas2) affects sex ratio, but the phenotypic effects of the other strains are unclear. These data reveal a dynamic interaction between Polytremis and Wolbachia endosymbionts affecting patterns of mtDNA variation.

Wolbachia infection status and molecular diversity in the species of tribe Tagiadini Mabille, 1878 (Lepidoptera: Hesperiidae) collected in China.

Wolbachia, one of the most ubiquitous heritable symbionts in lepidopteran insects, can cause mitochondrial introgression in related host species. We recently found mito-nuclear discordance in the Lepidopteran tribe Tagiadini Mabille 1878 from which Wolbachia has not been reported. In this study, we found that 13 of the 46 species of Tagiadini species tested were positive for Wolbachia. Overall, 14% (15/110) of Tagiadini specimens were infected with Wolbachia and nine new STs were found from 15 isolates. A co-phylogenetic comparison, divergence time estimation and Wolbachia recombination analysis revealed that mito-nuclear discordance in Tagiadini species is not mediated by Wolbachia, but Wolbachia acquisition in Tagiadini appears to have occurred mainly through horizontal transmission rather than codivergence.

Machine learning-based non-destructive terahertz detection of seed quality in peanut.

Rapid identification of peanut seed quality is crucial for public health. In this study, we present a terahertz wave imaging system using a convolutional neural network (CNN) machine learning approach. Terahertz waves are capable of penetrating the seed shell to identify the quality of peanuts without causing any damage to the seeds. The specificity of seed quality on terahertz wave images is investigated, and the image characteristics of five different qualities are summarized. Terahertz wave images are digitized and used for training and testing of convolutional neural networks, resulting in a high model accuracy of 98.7% in quality identification. The trained THz-CNNs system can accurately identify standard, mildewed, defective, dried and germinated seeds, with an average detection time of 2.2 s. This process does not require any sample preparation steps such as concentration or culture. Our method swiftly and accurately assesses shelled seed quality non-destructively.

Proteomic analysis of schistosoma japonicum schistosomulum proteins that are differentially expressed among hosts differing in their susceptibility to the infection.

Schistosomiasis is a tropical, parasitic disease affecting humans and several animal species. The aim of this study was to identify proteins involved in the growth and survival of the parasitic forms inside a host. Schistosomula of Schistosoma japonicum were isolated from three different hosts: the susceptible BALB/c mice; the Wistar rats, which have a considerably lower susceptibility; and the resistant reed vole, Microtus fortis. Soluble proteins of the schistosomula collected from the above three hosts 10 days postinfection were subjected to two-dimensional difference gel electrophoresis. Comparative proteomic analyses revealed that 39, 21, and 25 protein spots were significantly differentially expressed between schistosomula from mice and rats, mice and reed voles, or rats and reed voles, respectively (ANCOVA, p < 0.05). Further, the protein spots were identified by liquid chromatography-tandem MS. Bioinformatics analysis showed that the differentially expressed proteins were essentially those involved in the metabolism of proteins, ribonucleotides, or carbohydrates, or in stress response or cellular movement. This study represents the first attempt at profiling S. japonicum living in different states and provides a basis for a better understanding of the molecular mechanisms in the development and survival of S. japonicum in different host environments.

Optimal resource allocation method for energy harvesting based underlay Cognitive Radio networks.

This paper proposes an optimal resource allocation method. The method is to maximize the Energy Efficiency (EE) for an Energy Harvesting (EH) enabled underlay Cognitive Radio (CR) network. First, we assumed the Secondary Users (SUs) can harvest energy from the surrounding Radio Frequency (RF) signals. Then, we modelled the EE maximisation problem as a joint time and power optimization model. Next, the optimal EH time allocation factor can be calculated. After that the optimal power allocation strategy can be obtain by the fractional programming and Lagrange multiplier method. Finally simulation results show that the proposed iterative method can be better performance advantages compared with the exhaustive method and genetic algorithm. And the EE of this system model is significantly improved compared to the EE model without considering EH.

Specific detection of Echinococcus spp. from the Tibetan fox (Vulpes ferrilata) and the red fox (V. vulpes) using copro-DNA PCR analysis.

There are three Echinococcus species, Echinococcus granulosus, E. multilocularis, and E. shiquicus, which are distributed on the vast area of pastureland on the eastern Tibetan plateau in China. Tibetan foxes (Vulpes ferrilata) have been determined to be the main wild definitive host of E. multilocularis and E. shiquicus, but little information is available on the prevalence of these two parasites in Tibetan foxes. Consequently, the copro-prevalence of these parasites in foxes from the eastern Tibetan plateau was evaluated in this study. For each copro-DNA sample extracted from fox feces, a 133-bp segment of EgG1 Hae III was used to screen for infection with E. granulosus. Multiplex nested polymerase chain reaction (PCR) analysis was used to target an 874-bp segment of the mitochondrial COI gene to distinguish E. multilocularis and E. shiquicus. Among 184 fecal samples, 120 were from Tibetan foxes and six from red foxes (Vulpes vulpes). Of the fecal samples from Tibetan foxes, 74 (giving a copro-prevalence of 62%) showed the presence of Echinococcus spp.: 23 (19%) were found to contain E. multilocularis, 32 (27%) E. shiquicus, and 19 (16%) showed mixed infection with both E. multilocularis and E. shiquicus. Two fecal samples from red foxes were found to be infected with E. multilocularis. No fox feces were found to be infected with E. granulosus. Tests on zinc finger protein genes and a 105-bp fragment of the Sry gene found no significant difference in the prevalence of the two parasites between sexes. The efficiency of our multiplex nested PCR methods were compared with previous polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) methods and some problems associated with the copro-PCR were discussed.

Horizontal transmission and recombination of Wolbachia in the butterfly tribe Aeromachini Tutt, 1906 (Lepidoptera: Hesperiidae).

Wolbachia is arguably one of the most ubiquitous heritable symbionts among insects and understanding its transmission dynamics is crucial for understanding why it is so common. While previous research has studied the transmission pathways of Wolbachia in several insect lineages including Lepidoptera, this study takes advantage of data collected from the lepidopteran tribe Aeromachini in an effort to assess patterns of transmission. Twenty-one of the 46 species of Aeromachini species were infected with Wolbachia. Overall, 25% (31/125) of Aeromachini specimens tested were Wolbachia positive. All Wolbachia strains were species-specific except for the wJho strain which appeared to be shared by three host species with a sympatric distribution based on a cophylogenetic comparison between Wolbachia and the Aeromachini species. Two tests of phylogenetic congruence did not find any evidence for cospeciation between Wolbachia strains and their butterfly hosts. The cophylogenetic comparison, divergence time estimation, and Wolbachia recombination analysis revealed that Wolbachia acquisition in Aeromachini appears to have mainly occurred mainly through horizontal transmission rather than codivergence.

Wearable on-device deep learning system for hand gesture recognition based on FPGA accelerator.

Gesture recognition is critical in the field of Human-Computer Interaction, especially in healthcare, rehabilitation, sign language translation, etc. Conventionally, the gesture recognition data collected by the inertial measurement unit (IMU) sensors is relayed to the cloud or a remote device with higher computing power to train models. However, it is not convenient for remote follow-up treatment of movement rehabilitation training. In this paper, based on a field-programmable gate array (FPGA) accelerator and the Cortex-M0 IP core, we propose a wearable deep learning system that is capable of locally processing data on the end device. With a pre-stage processing module and serial-parallel hybrid method, the device is of low-power and low-latency at the micro control unit (MCU) level, however, it meets or exceeds the performance of single board computers (SBC). For example, its performance is more than twice as much of Cortex-A53 (which is usually used in Raspberry Pi). Moreover, a convolutional neural network (CNN) and a multilayer perceptron neural network (NN) is used in the recognition model to extract features and classify gestures, which helps achieve a high recognition accuracy at 97%. Finally, this paper offers a software-hardware co-design method that is worth referencing for the design of edge devices in other scenarios.

Diversity, Composition and Functional Inference of Gut Microbiota in Indian Cabbage white Pieris canidia (Lepidoptera: Pieridae).

We characterized the gut microbial composition and relative abundance of gut bacteria in the larvae and adults of Pieris canidia by 16S rRNA gene sequencing. The gut microbiota structure was similar across the life stages and sexes. The comparative functional analysis on P. canidia bacterial communities with PICRUSt showed the enrichment of several pathways including those for energy metabolism, immune system, digestive system, xenobiotics biodegradation, transport, cell growth and death. The parameters often used as a proxy of insect fitness (development time, pupation rate, emergence rate, adult survival rate and weight of 5th instars larvae) showed a significant difference between treatment group and untreated group and point to potential fitness advantages with the gut microbiomes in P. canidia. These data provide an overall view of the bacterial community across the life stages and sexes in P. canidia.

Phylogeny and Density Dynamics of Wolbachia Infection of the Health Pest Paederus fuscipes Curtis (Coleoptera: Staphylinidae).

The maternally inherited obligate intracellular bacteria Wolbachia infects the reproductive tissues of a wide range of arthropods and affects host reproduction. Wolbachia is a credible biocontrol agent for reducing the impact of diseases associated with arthropod vectors. Paederus fuscipes is a small staphylinid beetle that causes dermatitis linearis and conjunctivitis in humans when they come into contact with skin. Wolbachia occur in this beetle, but their relatedness to other Wolbachia, their infection dynamics, and their potential host effects remain unknown. In this study, we report the phylogenetic position and density dynamics of Wolbachia in P. fuscipes. The phylogeny of Wolbachia based on an analysis of MLST genotyping showed that the bacteria from P. fuscipes belong to supergroup B. Quantitative PCR indicated that the infection density in adults was higher than in any other life stage (egg, larva or pupa), and that reproductive tissue in adults had the highest infection densities, with similar densities in the sexes. These findings provide a starting point for understanding the Wolbachia infection dynamics in P. fuscipes, and interactions with other components of the microbiota.

Life History Effects Linked to an Advantage for wAu Wolbachia in Drosophila.

Wolbachia endosymbiont infections can persist and spread in insect populations without causing apparent effects on reproduction of their insect hosts, but the mechanisms involved are largely unknown. Here, we test for fitness effects of the wAu infection of Drosophila simulans by comparing multiple infected and uninfected polymorphic isofemale lines derived from nature. We show a fitness advantage (higher offspring number) for lines with the wAu Wolbachia infection when breeding on grapes, but only where there was Talaromyces and Penicillium fungal mycelial growth. When breeding on laboratory medium, the wAu infection extended the development time and resulted in larger females with higher fecundity, life history traits, which may increase fitness. A chemical associated with the fungi (ochratoxin A) did not specifically alter the fitness of wAu-infected larvae, which developed slower and emerged with a greater weight regardless of toxin levels. These findings suggest that the fitness benefits of Wolbachia in natural populations may reflect life history changes that are advantageous under particular circumstances, such as when breeding occurs in rotting fruit covered by abundant mycelial growth.

Molecular phylogeny of the butterfly tribe Baorini Doherty, 1886 (Hesperiidae, Hesperiinae) in China.

The butterfly tribe Baorini Doherty, 1886 is a large group of skippers. In this study, a total of 8 genera and 41 species of putative members of this tribe, which represent most of the generic diversity and nearly all the species diversity of the group in China, were sequenced for two mitochondrial genes and three nuclear genes (2084 bp). Phylogenetic relationships and subdivision of this tribe were investigated and the status of the genera are discussed. Partitioned maximum likelihood analyses were performed based on the combined dataset. Our results suggest that the data are split into two well-supported clades in the phylogeny tree. This analysis also represents the most complete phylogenetic analysis of the tribe Baorini in China to date, and includes several genera and species that have been previously excluded from published phylogenies of this group.

Molecular Phylogeny and Historical Biogeography of the Butterfly Tribe Aeromachini Tutt (Lepidoptera: Hesperiidae) from China.

: The butterfly tribe Aeromachini Tutt, 1906 is a large group of skippers. In this study, a total of 10 genera and 45 species of putative members of this tribe, which represent most of the generic diversity and nearly all the species diversity of the group in China, were sequenced for two mitochondrial genes and three nuclear genes (2093 bp). The combined dataset was analyzed with maximum likelihood inference using IQtree. We found strong support for monophyly of Aeromachini from China and support for the most recent accepted species in the tribe. Two paraphyletic genera within Aeromachini are presented and discussed. The divergence time estimates with BEAST and ancestral-area reconstructions with RASP provide a detailed description about the historical biogeography of the Aeromachini from China. The tribe very likely originated from the Hengduan Mountains in the late Ecocene and expanded to the Himalaya Mountains and Central China Regions. A dispersal-vicariance analysis suggests that dispersal events have played essential roles in the distribution of extant species, and geological and climatic changes have been important factors driving current distribution patterns.

Complete mitochondrial genome of the Chinese skipper, Polytremis jigongi (Lepidoptera: Hesperiidae).

The sequence of the mitochondrial genome (mitogenome) of Polytremis jigongi (Lepidoptera: Hesperiidae) has been presented in this article. It is 15,353 bp in length, with an A + T content of 80.9% containing 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and a noncoding control region (D-loop). All of the 37 typical animal mitochondrial genes were found. All protein-coding genes started with ATN as a start codon except for the gene COX1 that uses CGA as in other lepidopteran species. Five protein-coding genes use incomplete stop codon TA or T, while the others use TAA as stop codons. Most of the tRNA genes can be folded into a typical cloverleaf structure. Nucleotide composition is similar to other insects, showing a high bias toward A + T. Phylogenetic analysis showed that the genome sequence of P. jigongi is close to Hesperiidae.

Complete mitochondrial DNA genome of Polytremis nascens (Lepidoptera: Hesperiidae).

In this study, the complete mitochondrial DNA (mtDNA) sequence of Polytremis nascens (Lepidoptera: Hesperiidae) was determined. The 15,392 bp mitogenome with GenBank accession number KM981865 contained 13 protein genes, 22 tRNAs, 2 rRNAs, and a non-coding control region (D-loop). All the 37 typical animal mitochondrial genes were found. The overall base composition was 39.7% A, 40.7% T, 7.7% G and 11.9% C, with a high A + T content (80.4%). This complete mitogenome of P. nascens provides a basic data for studies on species identification, molecular systematics and conservation genetics.

Taxonomic status and molecular phylogeography of two sibling species of Polytremis (Lepidoptera: Hesperiidae).

The skipper Polytremis theca species complex is widely distributed in the south of the Qinling Mountains in China. A recent study of the Polytremis genus suggested that this species might encompass two differentiated lineages. We tested this hypothesis, by carrying out a phylogenetic study of this agricultural pest based on nationwide sampling and the evaluation of mitochondrial and nuclear DNA markers. We show that this species is actually an amalgamation of two sibling taxa (P. t. theca and P. t. fukia), which displayed levels of genetic divergence as great as those generally found between sister species in the Polytremis genus, suggesting that they actually correspond to two distinct species. The Divergence time estimates suggest that an active period of speciation within Polytremis occurred within the Pleistocene eras. Based on its distinct phylogenetic placement and geographical isolation, we suggest that the subspecies should be elevated to full species status under the phylogenetic species concept, which has significant management implications.