3,184 research outputs found
Reconfigurable Intelligent Surface-Empowered Self-Interference Cancellation for 6G Full-Duplex MIMO Communication Systems
With the advent of sixth-generation (6G) wireless communication networks, it
requires substantially increasing wireless traffic and extending serving
coverage. Reconfigurable intelligent surface (RIS) is widely considered as a
promising technique which is capable of improving the system data rate, energy
efficiency and coverage extension as well as the benefit of low power
consumption. Moreover, full-duplex (FD) transmission provides simultaneous
transmit and received signals, which theoretically enhances twice spectrum
efficiency. However, the self-interference (SI) in FD is a challenging task
requiring complex and high-overhead cancellation, which can be resolved by
configuring appropriate phase of RIS elements. This paper has proposed an
RIS-empowered full-duplex self-interference cancellation (RFSC) scheme to
alleviate the severe SI in an RIS-FD system. We consider the SI minimization of
RIS-FD uplink (UL) while guaranteeing quality-of-service (QoS) of UL users. The
closed-form solution is theoretically derived by exploiting Lagrangian method
under different numbers of RIS elements and receiving antennas. Simulation
results reveal that the proposed RFSC scheme outperforms the scenario without
RIS deployment in terms of higher signal-to-interference-plus-noise ratio
(SINR). Due to effective interference mitigation, the proposed RFSC can achieve
the highest SINR compared to other existing schemes in open literatures
Credit Scoring Based on Hybrid Data Mining Classification
The credit scoring has been regarded as a critical topic. This study proposed four approaches combining with the NN (Neural Network) classifier for features selection that retains sufficient information for classification purpose. Two UCI data sets and different approaches combined with NN classifier were constructed by selecting features. NN classifier combines with conventional statistical LDA, Decision tree, Rough set and F-score approaches as features preprocessing step to optimize feature space by removing both irrelevant and redundant features. The procedure of the proposed algorithm is described first and then evaluated by their performances. The results are compared in combination with NN classifier and nonparametric Wilcoxon signed rank test will be held to show if there has any significant difference between these approaches. Our results suggest that hybrid credit scoring models are robust and effective in finding optimal subsets and the compound procedure is a promising method to the fields of data mining
CoMP Enhanced Subcarrier and Power Allocation for Multi-Numerology based 5G-NR Networks
With proliferation of fifth generation (5G) new radio (NR) technology, it is
expected to meet the requirement of diverse traffic demands. We have designed a
coordinated multi-point (CoMP) enhanced flexible multi-numerology (MN) for
5G-NR networks to improve the network performance in terms of throughput and
latency. We have proposed a CoMP enhanced joint subcarrier and power allocation
(CESP) scheme which aims at maximizing sum rate under the considerations of
transmit power limitation and guaranteed quality-of-service (QoS) including
throughput and latency restrictions. By employing difference of two concave
functions (D.C.) approximation and abstract Lagrangian duality method, we
theoretically transform the original non-convex nonlinear problem into a
solvable maximization problem. Moreover, the convergence of our proposed CESP
algorithm with D.C. approximation is analytically derived with proofs, and is
further validated via numerical results. Simulation results demonstrated that
our proposed CESP algorithm outperforms the conventional non-CoMP and single
numerology mechanisms along with other existing benchmarks in terms of lower
latency and higher throughput under the scenarios of uniform and edge users
Robust Active and Passive Beamforming for RIS-Assisted Full-Duplex Systems under Imperfect CSI
The sixth-generation (6G) wireless technology recognizes the potential of
reconfigurable intelligent surfaces (RIS) as an effective technique for
intelligently manipulating channel paths through reflection to serve desired
users. Full-duplex (FD) systems, enabling simultaneous transmission and
reception from a base station (BS), offer the theoretical advantage of doubled
spectrum efficiency. However, the presence of strong self-interference (SI) in
FD systems significantly degrades performance, which can be mitigated by
leveraging the capabilities of RIS. Moreover, accurately obtaining channel
state information (CSI) from RIS poses a critical challenge. Our objective is
to maximize downlink (DL) user data rates while ensuring quality-of-service
(QoS) for uplink (UL) users under imperfect CSI from reflected channels. To
address this, we introduce the robust active BS and passive RIS beamforming
(RAPB) scheme for RIS-FD, accounting for both SI and imperfect CSI. RAPB
incorporates distributionally robust design, conditional value-at-risk (CVaR),
and penalty convex-concave programming (PCCP) techniques. Additionally, RAPB
extends to active and passive beamforming (APB) with perfect channel
estimation. Simulation results demonstrate the UL/DL rate improvements achieved
considering various levels of imperfect CSI. The proposed RAPB/APB schemes
validate their effectiveness across different RIS deployment and RIS/BS
configurations. Benefited from robust beamforming, RAPB outperforms existing
methods in terms of non-robustness, deployment without RIS, conventional
successive convex approximation, and half-duplex systems
CRONOS: Colorization and Contrastive Learning for Device-Free NLoS Human Presence Detection using Wi-Fi CSI
In recent years, the demand for pervasive smart services and applications has
increased rapidly. Device-free human detection through sensors or cameras has
been widely adopted, but it comes with privacy issues as well as misdetection
for motionless people. To address these drawbacks, channel state information
(CSI) captured from commercialized Wi-Fi devices provides rich signal features
for accurate detection. However, existing systems suffer from inaccurate
classification under a non-line-of-sight (NLoS) and stationary scenario, such
as when a person is standing still in a room corner. In this work, we propose a
system called CRONOS (Colorization and Contrastive Learning Enhanced NLoS Human
Presence Detection), which generates dynamic recurrence plots (RPs) and
color-coded CSI ratios to distinguish mobile people from vacancy in a room,
respectively. We also incorporate supervised contrastive learning to retrieve
substantial representations, where consultation loss is formulated to
differentiate the representative distances between dynamic and stationary
cases. Furthermore, we propose a self-switched static feature enhanced
classifier (S3FEC) to determine the utilization of either RPs or color-coded
CSI ratios. Our comprehensive experimental results show that CRONOS outperforms
existing systems that apply machine learning, non-learning based methods, as
well as non-CSI based features in open literature. CRONOS achieves the highest
presence detection accuracy in vacancy, mobility, line-of-sight (LoS), and NLoS
scenarios
Conformational change of the AcrR regulator reveals a possible mechanism of induction
The Escherichia coli AcrR multidrug-binding protein represses transcription of acrAB and is induced by many structurally unrelated cytotoxic compounds. The crystal structure of AcrR in space group P2221 has been reported previously. This P2221 structure has provided direct information about the multidrug-binding site and important residues for drug recognition. Here, a crystal structure of this regulator in space group P31 is presented. Comparison of the two AcrR structures reveals possible mechanisms of ligand binding and AcrR regulation
Involvement of F-Actin in Chaperonin-Containing t-Complex 1 Beta Regulating Mouse Mesangial Cell Functions in a Glucose-Induction Cell Model
The aim of this study is to investigate the role of chaperonin-containing t-complex polypeptide 1 beta (CCT2) in the regulation of mouse mesangial cell (mMC) contraction, proliferation, and migration with filamentous/globular-(F/G-) actin ratio under high glucose induction. A low CCT2 mMC model induced by treatment of small interference RNA was established. Groups with and without low CCT2 induction examined in normal and high (H) glucose conditions revealed the following major results: (1) low CCT2 or H glucose showed the ability to attenuate F/G-actin ratio; (2) groups with low F/G-actin ratio all showed less cell contraction; (3) suppression of CCT2 may reduce the proliferation and migration which were originally induced by H glucose. In conclusion, CCT2 can be used as a specific regulator for mMC contraction, proliferation, and migration affected by glucose, which mechanism may involve the alteration of F-actin, particularly for cell contraction
Attention-based Learning for Sleep Apnea and Limb Movement Detection using Wi-Fi CSI Signals
Wi-Fi channel state information (CSI) has become a promising solution for
non-invasive breathing and body motion monitoring during sleep. Sleep disorders
of apnea and periodic limb movement disorder (PLMD) are often unconscious and
fatal. The existing researches detect abnormal sleep disorders in impractically
controlled environments. Moreover, it leads to compelling challenges to
classify complex macro- and micro-scales of sleep movements as well as
entangled similar waveforms of cases of apnea and PLMD. In this paper, we
propose the attention-based learning for sleep apnea and limb movement
detection (ALESAL) system that can jointly detect sleep apnea and PLMD under
different sleep postures across a variety of patients. ALESAL contains
antenna-pair and time attention mechanisms for mitigating the impact of modest
antenna pairs and emphasizing the duration of interest, respectively.
Performance results show that our proposed ALESAL system can achieve a weighted
F1-score of 84.33, outperforming the other existing non-attention based methods
of support vector machine and deep multilayer perceptron
Doping and temperature dependence of electron spectrum and quasiparticle dispersion in doped bilayer cuprates
Within the t-t'-J model, the electron spectrum and quasiparticle dispersion
in doped bilayer cuprates in the normal state are discussed by considering the
bilayer interaction. It is shown that the bilayer interaction splits the
electron spectrum of doped bilayer cuprates into the bonding and antibonding
components around the point. The differentiation between the bonding
and antibonding components is essential, which leads to two main flat bands
around the point below the Fermi energy. In analogy to the doped
single layer cuprates, the lowest energy states in doped bilayer cuprates are
located at the point. Our results also show that the striking
behavior of the electronic structure in doped bilayer cuprates is intriguingly
related to the bilayer interaction together with strong coupling between the
electron quasiparticles and collective magnetic excitations.Comment: 9 pages, 4 figures, updated references, added figures and
discussions, accepted for publication in Phys. Rev.
3510-V 390-m Omega . cm(2) 4H-SiC Lateral JFET on a Semi-Insulating Substrate
The performance of high-voltage 4H-SiC lateral JFETs on a semi-insulating substrate is reported in this letter. The design of the voltage-supporting layers is based on the charge compensation of p- and n-type epilayers. The best measured breakdown voltage is 3510 V, which, to the authors\u27 knowledge, is the highest value ever reported for SiC lateral switching devices. The R-on of this device is 390 m Omega . cm(2), in which 61% is due to the drift-region resistance. The BV2/R-on is 32 MW/cm(2), which is typical among other reported SiC lateral devices
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