This paper elaborates on a new class of orthonormal power-based algorithms for fast estimation and tracking of the principal or minor subspace of a vector sequence. The proposed algorithms are closely related to the natural power method that has the fastest convergence rate among many power-based methods such as the Oja method, the projection approximation subspace tracking (PAST) method, and the novel

We examine how the Coronavirus pandemic affected consumer valuation of digital services. Governments responded to the pandemic with various forms of lockdowns and social distancing, leading to increased dependence on digital services for work, social engagement, and leisure activities. We identify consumer valuations through surveys where respondents express their reservation prices for digital services

Wireless sensor networks play the most important role in the internet of things (IoT). Due to the extensive development of sensor networks, the innate limitations and characteristics of the resources in sensors, and heterogeneity of equipment, wireless sensor network has been confronted with security challenges and various vulnerabilities. One way to improve the reliability of the sensor networks is

Traditional methods ignore the imbalance of network data, resulting in unsatisfactory clustering detection results, long detection time, and high rate of missed detection and false alarm. In this regard, this paper proposes a clustering detection method of network intrusion feature based on support vector machine and LCA block algorithm. Firstly, the useless features were deleted by reducing the dimension

The traditional intrusion detection technology has some shortcomings, such as high hardware requirements and harsh detection conditions etc. This paper proposes an environment intrusion detection technology based on WiFi, which uses the existing WiFi network to realize security monitoring function, covers a wide range and does not expose privacy. Firstly, the technology uses median filtering to denoise

Nowadays the security assurance of information in Mobile Adhoc Networks (MANETs) is achieved by using secret keys. The dynamic and unpredictable nature of the network places challenges before the researchers in developing a suitable key generation method. Many of the present-day works aim at identifying passive attackers in the network and to protect the information from them. Active attackers are

In order to improve the accuracy of detection the image defect, a method to detect the edge defect based on modal symmetry algorithm was put forward. The improved PCNN was used to deal with the salt-pepper noise and Gaussian noise in image. On this basis, the semantic learning and annotation of image features were achieved. At first, the corresponding features were extracted from the original image

Data collection is a key operation in wireless sensor networks. In view of the privacy-preserving problem of the existing data collection schemes, this paper proposes a secure and verifiable continuous data collection algorithm (SVCDC) in wireless sensor networks. Taking the temporal correlation of sensory data into consideration, SVCDC reconstructs multiple sensory data in one period, which can effectively

It is reported in the literature that there are widespread adoption and use of Mobile Instant Messaging (M.I.M.) among businesses. However, there is a lack of academic publication in this area that demonstrates by means of a case study that the M.I.M. implementation for S.M.E.'s can improve operational processes. In this case study, the company recently moved much of its Product Ordering (P.O.) processes

The Dynamic on demand network formation feature of MANET tend to have its biggest the vulnerability that infect the process of route establishment using routing algorithms and exploits many attacks. Identifying the attack and isolating the malicious node to reform the secured routing environment is the major goal of all researchers working for securing the MANET. IDS and trust based collaborative approach

The medical enhancements have been improved to increase the life span of mankind. High penetration of Wireless Sensor Network in medical field helped the doctors to diagnose the patience in accurate manner and prescribe the medicines accordingly. In this modern Era, many people have permanent implant like face maker and it is life threatening to keep changing this body enhancement and it is need to

In time division duplexing based mobile networks, under certain atmospheric ducting conditions, the uplink reception may be interfered by the downlink transmissions of remote base-stations (gNBs) located hundreds of kilometers away. This paper addresses such remote interference problem in a 5G new radio (NR) macro deployment context. Specifically, two potential reference signal (RS) designs for remote

In recent years, deep convolutional neural networks have played an increasingly important role in single-image super-resolution (SR). However, with the increase of the depth and width of networks, the super-resolution methods based on convolution neural networks are facing training difficulties, memory consumption, running slowness and other problems. Furthermore, most of the methods do not make full

In recent years, linguistic generative steganography has been greatly developed. The previous works are mainly to optimize the perceptual-imperceptibility and statistical-imperceptibility of the generated steganographic text, and the latest developments show that they have been able to generate steganographic texts that look authentic enough. However, we noticed that these works generally cannot control

Maximum likelihood (ML) amplitude and noise variance estimation without having to jointly estimate the frequency and the phase and based only on information from the noisy received signal magnitude, is studied for a single sinusoid in complex additive white Gaussian noise. This estimation problem is equivalent to the classic problem of parameter estimation for the Rician distribution. While solving

Existing learning-based dehazing methods are prone to cause excessive dehazing and failure to dense haze, mainly because that the global features of hazy images are not fully utilized, while the local features of hazy images are not enough discriminative. In this letter, we propose a Recurrent Context Aggregation Network (RCAN) to effectively dehaze images and restore color fidelity. In RCAN, an efficient

Recently, convolutional neural networks (CNN) have been widely used in image denoising. But with most CNN denoising methods, all the channels are treated equally and the relationship between spatial locations are neglected. In the letter, we propose a novel channel and space attention neural network (CSANN) for image denoising. In CSANN, we concatenate the noise level with the average and maximum values

Digital audio equalization is a very common procedure in the acoustic field that allows to improve the listening experience by adjusting the auditory frequency response. The design of graphic equalizers introduces several problems related to the necessity of implementing high performing filters with linear phase, usually characterized by high computational complexity. This paper proposes an innovative

We consider a two-way half-duplex decode-and-forward (DF) relaying system with multiple pairs of single-antenna users assisted by a cell-free (CF) massive multiple-input multiple-output (mMIMO) architecture with multiple-antenna access points (APs). Under the practical constraint of imperfect channel state information (CSI), we derive the achievable sum spectral efficiency (SE) for a finite number

As an important part of wireless communication systems, the technology of RF devices and circuits has been progressing rapidly. For high-frequency and high-power applications, vacuum electronic devices (e.g., traveling wave tubes) have been widely used, although the vacuum tube is large in size and hard to integrate.

This work presents a new and efficient approach for enhancing the bandwidth and reducing the E-plane cross-polarization (X-pol) of an epsilon negative transmission line (ENG-TL) antenna with reduced size for working in 2.4 GHz Industrial, Scientific and Medical (ISM) band. The antenna consists of ENG-TL on which a curved meander line inductor is loaded for the generation of zeroth-order resonance mode

The paper presents the results of a novel high-gain dual-band magneto-electric dipole (MED) antenna. The antenna comprises two pairs of horizontal metal plates of different heights that are excited by a Γ-shaped feedline structure. The antenna is entirely made of metal plates. Compared to traditional MED antennas, the proposed design exhibits dual-band operation with a higher radiation gain whose frequency

This paper has proposed a photonic microwave waveforms generation scheme based on a dual-polarization Mach–Zehnder modulator (DPol-MZM) at moderate modulation depth without optical filtering. In the scheme, two sub-MZMs are driven by a fundamental frequency and a frequency tripled signal, respectively, to perform the optical carrier suppression modulation along two orthogonal polarization directions

Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

In this letter, the problem of monopulse angle estimation error under mainlobe interference for dual- polarization array is investigated. The adaptive monopulse angle estimation considering cross polarization with array beam scanning is analyzed. To reduce the angle estimation error, an adaptive polarization-constrained monopulse approach based on combined constrained cross polarization and main polarization

A dual-bowtie antenna loaded with a double-sided dielectric lens is presented for wideband and high gain performance. The dielectric lens is a combination of the elliptical and conical frustum lenses formed on two sides (top and bottom) of a rectangular dielectric block, respectively. The conical frustum lens is mounted at the backside of the bowtie radiator to collect the radiated energy toward the

The wideband radar system is usually exploited to obtain the 3-D image of the target under test. However, the wide bandwidth increases the system complexity and cost. Emerging techniques, such as the reconfigurable reflectarrays, reconstruct a near 3-D image via using single-frequency millimeter-wave (MMW) and near-field focusing of the beam, which greatly simplifies the system design, whereas the

In this letter, a low-profile wideband pattern diversity antenna based on metasurface (MTS) is proposed. Initially, based on the theory of characteristic mode (TCM), the two adjacent intrinsic modes, which correspond to the broadside and conical radiation pattern, respectively, are exploited to realize a wideband pattern diversity characteristic under a low profile. Then, by analyzing the modal current

A grooved metal ground with slits is utilized to achieve scattering cross section (SCS) reduction of a microstrip patch array antenna in this letter. By arranging the grooves and slits on the ground, 180° scattering phase differences between the elements on the ground and in the grooves are attained on the aperture, and obvious SCS reduction is obtained in a broadband. The proposed low-SCS microstrip

Economical sensing and recording of temperature are important in the transportation and management of fragile goods such as medicine, fish/poultry, and other temperature-sensitive items. Existing approaches measure the entire temperature profile using electronic devices running on a continuous power source. This letter presents a simple, intelligent, and battery-free solution for capturing interesting

This letter presents a compact cavity-backed slot antenna using dual mode for Internet of Things (IoT) applications. The proposed antenna has stub structures for generating additional resonant mode, by which two polarization components orthogonal to each other are realized within the impedance bandwidth. By the combination of the two modes, circularly polarized radiation is generated. The impedance

This letter explores geometrical optics-based raytracing in combination with modal analysis to realize an open cavity structure as an advanced variant of the resonant cavity antenna (RCA). Additional ray confinement has been ensured by determining accurate phase-locking conditions as demonstrated for the first time. Its combination with the analysis of the cavity mode has also been introduced to determine

This letter presents a novel wideband printed circuit board (PCB)-stacked Luneburg lens antenna with a flared open edge for multibeam scanning application at 5G millimeter-wave band. The lens consists of two groups of parallel PCBs. Each group includes 12 layers of low-cost FR4 PCB, which are fixed by metal screws. Inside the lens there is no dielectric, resulting in an air-filled structure. With drilling

A novel 2-D composite right/left-handed transmission line (CRLH-TL) metamaterial in polar coordinates is proposed for the first time, and applied to a multistandard antenna. The prototype antenna with triband operation and colocated pattern and polarization diversity is specifically designed to eliminate the need for multiple antennas in the processing center side and to significantly reduce antenna

A dual-polarized (DP) metasurface (MTS) antenna with miniaturized radiating aperture is proposed for polarimetric synthetic aperture radar. The antenna consists of an MTS radiator and a cross aperture antenna. Characteristic mode analysis (CMA) is utilized to analyze the working mechanism of the MTS radiator and to guide the miniaturization of the radiating aperture. Then, the CMA is used for the optimization

This letter presented a nematic liquid crystal (LC) based metal-dielectric-metal structure to fully electronically modulate the reflection phase of electromagnetic waves. The demonstrated structure is composed of a thin LC layer sandwiched between copper comb electrodes and a single slotted reflection array. Based on a proper application of the external electric field, the whole process of nematic

A design method using simple patches with nonresonant mode to achieve broadband phase-gradient metasurfaces of reflective type is proposed and an example to apply it for radar cross section (RCS) reduction is given. The method is based on treating the patch in an element as a pixel and the phase differences are obtained by setting the pixels to be empty or full. As only two states can be guaranteed

This letter presents the design of a single point-fed, geometrically simple circularly polarized (CP) antenna for 28 GHz Ka-band applications. The proposed antenna is based on a straight microstrip line printed on one side and coupled with the nearly square patches through a 45° inclined V-shaped slot aperture on the other side. In order to generate circular polarization, the fundamental radiating

This letter presents a novel concept of beam-steerable transponder based on antenna array and phased modulators. The steerability of the beam is achieved by optimally delaying the modulated reflected signal at each antenna element (i.e., changing the phase in frequency domain) with load modulation technique. In this manner, the reflected backscattered signal power can be maximized at one particular

A dielectric slab waveguide based four-element leaky-wave antenna array configuration, with open-stopband suppression, operating in K $_a$ -band is presented. A one-to-four power divider using Y-junctions is developed for the feed network of the antenna array. Leaky-wave antennas are inherently directive in the plane of the length of the aperture. Owing to the array configuration, the beamwidth of

A millimeter-wave dual-band shared-aperture high-efficiency reflectarray antenna (RA) based on the structure-reuse technique is proposed in this letter, which consists of two sets of elements with full 360° phase compensation ranges. The oblique dipole element excited by the substrate integrated waveguide (SIW) is employed for the lower frequency band. The equivalent metallic waveguide element with

In this letter, a multiple-input–multiple-output (MIMO) antenna with wideband performance for 5G smartphones is presented. First, a planar inverted-F antenna (PIFA) with an inverted-T-shaped open-slot is introduced. The proposed PIFA operates with a wide bandwidth of 78% due to the multimode technology. Then, two such PIFAs are attempted to be merged as a PIFA-pair, constituting a 2 × 2 sub-MIMO antenna

In this letter, a novel and compact 180° circular sector microstrip antenna has been proposed. The patch surface has been designed with a proper design insight to perturb and control the orthogonal surface current paths and orthogonal field components at the truncated edges for suppression of cross-polar (XP) radiations over the whole elevation without hampering its radiation pattern and bandwidth

Sum and difference beams are two kinds of field patterns, which have been commonly used in monopulse radar systems for detecting and tracking targets. This letter proposes to synthesize sum and difference beams based on a binary programmable metasurface (BPM). Moreover, the sum and difference beams can be steered by reprogramming digital coding schemes of the BPM. A prototype of the BPM is designed

This letter presents a compact 2-D Butler matrix (BM) realized by multilayer substrate integrated waveguide (SIW) technology. The 2-D BMs in the open literature suffer from either bulky size or poor integration with the radiation portion. Facing this issue, a new SIW 2-D BM is developed and realized in planar configuration easily integrated with the slot antenna array. The key point of this letter

In this letter, a physical optics (PO)-based scattered field calculation method is introduced. The proposed method divides the object into circular meshes. This technique exploited the analytical solution of scattered fields from circular plates to make it compatible with the PO surface integral framework. Therefore, it has no need for triangular-based surface reconstruction. The proposed method is

In this letter, an electronically beam scanning reflectarray antenna is implemented using nematic liquid crystals (LCs). By loading a tunable phase shifter with a delay line structure in the resonance unit, the phase shift is achieved by tuning the dielectric constant of the LCs with a fixed structure through an external dc bias voltage for each unit. In doing so, dynamically controlling the reflection

In this letter, a high-gain circularly polarized (CP) array antenna with low profile and low grating lobe property is proposed. The array is composed of high-gain and low sidelobe CP patch elements based on odd high-order modes. By adding perturbation structure, a pair of orthogonal modes (TM 30 /TM 03 ) of the patch with 90° phase difference is diagonally excited. Meanwhile, by introducing five circular

A novel wideband substrate integrated waveguide (SIW) cavity-backed antenna element and its array are proposed in this letter. The proposed linearly polarized array element consists of a SIW cavity, stacked patches, and a coaxial probe. The SIW cavity-backed array element is implemented with physically connected stacked patch. The coaxial pin is directly connected to the two patch radiators. Blind

A 3-D printed multibeam spherical lens antenna with 2-D ultrawide-angle coverage is presented in this letter. The two-layer spherical dielectric lens can be fabricated easily by 3-D printing technology based on the effective medium theory. The circularly polarized U-slot patch antenna is introduced as the feed for the spherical lens due to its good radiation performance and compact configuration. The

This letter presents a 4 × 4 single-layer dual-band array antenna operating in the K - and Ka -band using gap waveguide (GW) technology. Radiating elements consist of I-shaped slots located on the top plate of the antenna and backed by a novel coaxial cavity with the dual-frequency operation. The antenna presents two ports, one for each band, and radiates a directive far field pattern with linear polarization

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

It is well known that any finite commutative ring is isomorphic to a direct product of local rings via the Chinese remainder theorem. Hence, there is a great significance to the study of character sums over local rings. Character sums over finite rings have applications that are analogous to the applications of character sums over finite fields. In particular, character sums over local rings have many

With the wide application of unmanned aerial vehicles (UAV) in industrial production, transportation, and entertainment, it is urgent to identify UAVs in time. Traditional UAV recognition mainly depends on wireless communication, which puts forward high requirements for a communication environment and has no way to deal with non-cooperative targets. Therefore, it is urgent to explore a UAV target recognition

In this paper, we consider the physical layer security of cooperative multiple relays networks, where the source tries to communicate the destination via modify-and-forward (MF) relaying in the presence of eavesdropper. More practical, transceiver residual hardware impairments (TRHIs) and channel estimation errors (CEEs) are taken into account. To improve secure performance and energy efficiency, the

It is vital to authenticate the content of speech signals to prevent the framing of innocent individuals. Furthermore, lack of speech content authentication may lead to repudiation. The research problem of authenticity vs falsehood is timely considering the recent worldwide interest in fake news and viral manipulated media. Liu & Wang proposed an algorithm to detect tamperings in speech content, based

Mobile grid computing has been a popular topic for researchers due to mobile and IoT devices’ ubiquity and their evergrowing processing potential. While many scheduling algorithms for harnessing these resources exist in the literature for standard grid computing scenarios, surprisingly, there is little insight into this matter in the context of hybrid-powered computing resources, typically found in

Surface roughness is a crucial parameter for the estimation of soil moisture (SM). The present study attempted to optimize the surface roughness parameter (h) for the estimation of SM from Soil Moisture Active Passive (SMAP) using tau–omega (τ-ω) model and also downscaled the estimated SM product using a polynomial regression relation among Normalized Difference Vegetation Index (NDVI), land surface