In this paper, we focus on both the communication and sensing security in the proposed multiple-subcarrier (MC) non-orthogonal multiple access (NOMA)-assisted integrated sensing and communication (ISAC) systems, where an active eaves-dropper is considered with imperfect channel state information (CSI). We consider a secure ISAC design by adopting the proposed secrecy rate and secrecy Cramér-Rao bound (S-CRB) metrics under the bounded CSI errors model. The joint design of artificial noise (AN) and dual-functional radar communications (DFRC) signals beamforming as well as subcarrier allocation is formulated to maximize the minimum achievable rate, while ensuring the hierarchical confidentiality requirements for users and satisfying the leakage CRB constraint for the target. To handle the non-convex problem, we devise a low-complexity successive convex approximation (SCA)-based suboptimal algorithm, and its ε-optimality is validated via our proposed branch and bound (B&B) algorithm in simulations. Numerical results reveal the effectiveness and superiority of our proposed scheme compared to the other baselines. Moreover, the inherent win-win relationship between the sum secrecy rate and target S-CRB is demonstrated via various simulation results, which provides several insights into secure MC-NOMA ISAC network deployment.

This paper proposes multiple-error interceptive voter designs for safety-critical applications. The proposed baseline voters comprise two-stage error-filters, in which the first stage includes two parallel C-elements (CEs) and the second stage includes one CE to filter soft errors. The voters have high-speed versions, any of which is embedded with a high-speed path from its original input to its output to reduce delay. Simulation results demonstrate the soft error tolerance of the proposed voters. Moreover, compared with the triple-modular-redundancy (TMR) voter that can only tolerate single soft errors, the proposed 3-input baseline and 4-input high-speed voters can tolerate double soft errors and can reduce the area-power-delay product by 77.03% and 95.05%, respectively, due to the use of a few transistors and a high-speed path. The voters are extended to intercept N-1 soft errors, N being the number of inputs of each voter. Note that the voters are also extended to make so that they can tolerate hard/permanent errors in addition to soft errors.

As a revolutionary technology, reconfigurable intelligent surface (RIS) has been deemed as an indispensable part of the 6th generation communications due to its inherent ability to regulate the wireless channels. However, passive RIS (PRIS) still suffers from some pressing issues, one of which is that the fading of the entire reflection link is proportional to the product of the distances from the base station to the PRIS and from the PRIS to the users, i.e., the productive attenuation. To tackle this problem, active RIS (ARIS) has been proposed to reconfigure the wireless propagation condition and alleviate the productive attenuation. In this paper, we investigate the physical layer security of the ARIS assisted non-orthogonal multiple access (NOMA) networks with the attendance of external and internal eavesdroppers. To be specific, the closed-form expressions of secrecy outage probability (SOP) and secrecy system throughput are derived by invoking both imperfect successive interference cancellation (ipSIC) and perfect SIC. The secrecy diversity orders of legitimate users are obtained at high signal-to-noise ratios. Numerical results are presented to verify the accuracy of the theoretical expressions and indicate that: i) The SOP of ARIS assisted NOMA networks exceeds that of PRIS-NOMA, ARIS/PRIS-assisted orthogonal multiple access (OMA); ii) Due to the balance between the thermal noise and residual interference, introducing excess reconfigurable elements at ARIS is not helpful to reduce the SOP; and iii) The secrecy throughput performance of ARIS-NOMA networks outperforms that of PRIS-NOMA and ARIS/PRIS-OMA networks.

With the rapid advancement of CMOS technologies, integrated circuits are becoming more prone to soft errors, e.g., triple-node upsets (TNUs). In this paper, to effectively tolerate TNUs, an input-split C-element-based DICEs (IC-DICEs) based TNU-recovery latch is proposed. The latch employs three interlocked IC-DICEs to allow recovering from any TNU. Simulations demonstrate the TNU recovery of the latch, and also demonstrate that the proposed latch can reduce delay by 87.21%, area by 27.04%, and delay-area-power product (DAPP) by 87.44% on average, compared to the alternative latches.

In this paper, the sea surface wind speed (SSWS) retrieval accuracy for HaiYang-2C (HY-2C) scatterometer in the coastal regions is evaluated. To improve coastal SSWS accuracy, we use the European Centre for Medium-range Weather Forecast Reanalysis 5th Generation (ECMWF ERA5) data as the reference output to establish the coastal multi-interval SSWS retrieval model based on the light gradient boosting model (LGBM). Compared with the ERA5 wind speed, the root mean square error (RMSE) of the LGBM-based model in the low, medium, and high wind speed ranges is 36.36%, 33.33%, and 34.52% lower than that of the HY-2C wind product, respectively. This paper also compares the SSWS retrieval results with the National Data Buoy Center buoy measurements. Compared to the HY-2C L2B wind product, the RMSE is reduced by 21.05%. This paper provides a dependable reference to coastal SSWS retrieval of HY-2C scatterometer observations.

Reconfigurable intelligent surface (RIS) has been regarded as a promising technology since it has ability to create the favorable channel conditions. This paper investigates the secrecy performance of RIS aided non-orthogonal multiple access (NOMA) networks, where the internal eavesdropping scenario is taken into consideration. More specifically, novel closed-form and asymptotic expressions of secrecy outage probability for the k-th user are derived. According to the analytical results, the secrecy diversity orders at users are acquired in the high signal-to-noise ratio region. Simulation results show that the applying of RIS in NOMA networks can remarkably improve the performance of secrecy outage behaviour and secrecy system throughput compared to RIS aided orthogonal multiple access networks.

Abstract In this paper, an intelligent reflecting surface (IRS) assisted cooperative non‐orthogonal multiple access and mobile edge computing (NOMA‐MEC) system is proposed, where a base station sends signals to users through the virtue of the IRS. When the direct links between the base station and the user are blocked, the offloading tasks will be refracted to the near‐end user through the IRS and forwarded to the remote user, where the near‐end user is equipped with an MEC server working at full duplex or half duplex mode. To evaluate the potential performance of IRS aided cooperative NOMA‐MEC, new closed‐form expressions of the offloading outage probability is deduced for a pair of users. The asymptotic expressions of offloading outage probability are provided in the high signal‐to‐noise ratio regime. Simulation results are presented to substantiate the analyses and demonstrate that: (i) The offloading outage behaviors of IRS‐aided cooperative NOMA‐MEC systems are superior to that of NOMA‐MEC without IRS and IRS‐aided OMA‐MEC; (ii) As the value of parameter Q increases, the IRS‐aided NOMA‐MEC system is capable of achieving the enhanced offloading outage performance; (iii) By comparing with NOMA‐MEC without IRS and IRS‐aided OMA‐MEC, the energy efficiency and system throughput of IRS‐aided NOMA‐MEC has obvious advantages in delay‐limited transmission mode.

Approximately 13%–40% of patients with Crohn's disease (CD) show a primary loss of response to infliximab (IFX) therapy. Therefore, differentiating potential responders from primary nonresponders is clinically important. In this double-center study, we developed and validated a computed tomography enterography (CTE)-based radiomic signature (RS) for identification of CD patients at high risk of primary nonresponse (PNR) to IFX therapy, and demonstrated its incremental value to the clinical model. A total of 244 patients (training cohort, n = 119; test cohort 1, n = 51; test cohort 2, n = 74) were retrospectively recruited. Their clinical data and pretreatment CTE were retrieved and analyzed. All patients underwent IFX induction therapy. Reliability of clinical factors and radiomic-based features were assessed with the area under the receiver operating characteristic curve (AUC). In all, 1130 radiomic features were extracted from the whole inflamed gut in CTE images. In training cohort and test cohorts 1 and 2, the RS that discriminated PNR to IFX therapy yielded AUCs of 0.848, 0.789, and 0.789, respectively (all p < 0.05). By combining the clinical predictors (C-reactive protein, albumin, and body mass index) and RS, the radiomic-clinical model showed an increase in predicting performance (AUCs: 0.864, 0.794, and 0.791, respectively; all p < 0.05). Decision curve analysis and net reclassification improvement demonstrated the clinical usefulness of the radiomic-clinical model. In this study, the proposed RS showed potential as a clinical aid for the accurate identification of CD patients at high risk of PNR to IFX therapy before treatment. A combination of the RS and existing clinical factors might enable a step forward precise medicine.

This paper investigates the impact of physical layer secrecy on the performance of a unified non-orthogonal multiple access (NOMA) framework, where both external and internal eavesdropping scenarios are examined. The spatial locations of legitimate users (LUs) and eavesdroppers are modeled by invoking stochastic geometry. To characterize the security performance, new exact and asymptotic expressions of secrecy outage probability (SOP) are derived for both code-domain NOMA (CD-NOMA) and power-domain NOMA (PD-NOMA), in which imperfect successive interference cancellation (ipSIC) and perfect SIC (pSIC) are taken into account. For the external eavesdropping scenario, the secrecy diversity orders by a pair of LUs (the n-th user and m-th user) for CD/PD-NOMA are obtained. Analytical results make known that the diversity orders of the n-th user with ipSIC/pSIC for CD-NOMA and PD-NOMA are equal to zero/K and zero/one, respectively. The diversity orders of the m-th user are equal to K/one for CD/PD-NOMA. For the internal eavesdropping scenario, we examine the analysis of secrecy diversity order and observe that the m-th user to wiretap the n-th user with ipSIC/pSIC for CD-NOMA and PDNOMA provide the diversity orders of zero/K and zero/one, respectively, which is consistent with external eavesdropping scenario. Numerical results are present to confirm the accuracy of the analytical results developed and show that: i) The secrecy outage behavior of the n-th user is superior to that of the m-th user; ii) By increasing the number of subcarriers, CD-NOMA is capable of achieving a larger secrecy diversity gain compared to PD-NOMA.PD-NOMA.

This paper investigates the impact of physical layer secrecy on the performance of a unified non-orthogonal multiple access (NOMA) framework. The spatial locations of legitimate users (LUs) and eavesdroppers are governed by invoking stochastic geometry. To characterize the secrecy performance of the unified framework, new exact and asymptotic expressions of secrecy outage probabilities are derived, in which both imperfect successive interference cancellation (ipSIC) and perfect SIC (pSIC) schemes are taken into account. The secrecy diversity orders achieved by a pair of LUs (the n-th user and m-th user) for CD/PD-NOMA are obtained. Analytical results make known that the secrecy diversity orders of LUs with ipSIC/pSIC for CD/PD-NOMA are equal to zero/K and zero/one, respectively. Finally, numerical results are present to confirm the accuracy of the developed analytical results.

In this study, the authors consider multi‐user millimetre wave (mmWave) multiple‐input multiple‐output (MIMO) downlink communications for multi‐carrier scenarios, e.g. orthogonal frequency‐division multiplexing (OFDM) a common analogue precoder and combiner for the transmitter and receiver to maximise spectral efficiency is the main challenge for multi‐carrier MIMO systems, they propose two methods to solve this problem. The first method designs the analogue precoder and combiner based on the channel average of all subcarriers, which helps reduce computational complexity. Moreover, the channels of all subcarriers can be viewed as a third‐order tensor, and the second method is based on tensor unfolding, which makes full use of the channel information of all subcarriers. When the common analogue precoder and combiner are fixed, they consider designing a digital precoder to maximise the signal‐to‐leakage‐plus‐noise ratio of each user in every subcarrier, which leads to closed‐form solutions compared with the block diagonal method. Simulation results demonstrate that the performance of the proposed methods is close to that of the fully digital precoding method, and increasing the number of RF transceiver chains helps improve the performance of the proposed methods.

In this paper, we propose a hybridly connected structure for hybrid beamforming in millimeter-wave (mmWave) massive MIMO systems, where the antenna arrays at the transmitter and receiver consist of multiple sub-arrays, each of which connects to multiple radio frequency (RF) chains, and each RF chain connects to all the antennas corresponding to the sub-array. In this structure, through successive interference cancelation, we decompose the precoding matrix optimization problem into multiple precoding sub-matrix optimization problems. Then, near-optimal hybrid digital and analog precoders are designed through factorizing the precoding sub-matrix for each sub-array. Furthermore, we compare the performance of the proposed hybridly connected structure with the existing fully and partially connected structures in terms of spectral efficiency, the required number of phase shifters, and energy efficiency. Finally, simulation results are presented to demonstrate that the spectral efficiency of the hybridly connected structure is better than that of the partially connected structure and that its spectral efficiency can approach that of the fully connected structure with the increase in the number of RF chains. Moreover, the proposed algorithm for the hybridly connected structure is capable of achieving higher energy efficiency than existing algorithms for the fully and partially connected structures.

Although solid-state weather radars have been implemented for years, the application of solid-state transmitter along with pulse compression which improves the range resolution and detection performance in weather radar systems is still lack of strong evidence on its data reliability. In this paper, a solid-state weather radar with an optimized combined-pulses transmission mode is proposed to satisfy a minimized the blind zone and maximized detection range. Reflectivity factors data from klystron weather radar (sites nearby), which is considered very accurate, is used as the criterion for evaluating solid-state's data quality. Comparison and statistics show that solid-state weather radar has high detection accuracy in practical application.

In this paper, a consensus tracking problem of nonlinear multiagent systems is investigated under a directed communication topology. All the followers are modeled by stochastic nonlinear systems in nonstrict feedback form, where nonlinearities and stochastic disturbance terms are totally unknown. Based on the structural characteristic of neural networks (in Lemma 4), a novel distributed adaptive neural control scheme is put forward. The raised control method not only effectively handles unknown nonlinearities in nonstrict feedback systems, but also copes with the interactions among agents and coupling terms. Based on the stochastic Lyapunov functional method, it is indicated that all the signals of the closed-loop system are bounded in probability and all followers' outputs are convergent to a neighborhood of the output of leader. At last, the efficiency of the control method is testified by a numerical example.

In this paper, an LDPC based MIMO scheme is proposed in which matrix modulation scheme of MIMO and unequal protection ability of irregular LDPC codes are employed. The new scheme named degree distribution based-MIMO (DDB-MIMO for short) combines the two schemes, in which the important bits with large degrees are transmitted in transmission diversity (TD) symbols and bits with small degrees are mapped to the spatial multiplexing (SM) mode symbols. Since the TD mode could offer more protection to the data streams by offering more transmission power, the important bits with large degrees which could contribute more to the decoding process would have more protection from TD mode and hence the system performance would be improved namely. The performance of the new scheme has also been evaluated by the Gaussian approximation (GA) scheme which is used to analyze the asymptotic performance of LDPC coded system. The analysis results provide us the optimal mapping fractions between the bits with different degrees and transmitted symbols in different modes which is almost the same as the DDB-MIMO scheme offering. The simulation results also proved the new scheme.