63 research outputs found
ISAC Meets SWIPT: Multi-functional Wireless Systems Integrating Sensing, Communication, and Powering
This paper unifies integrated sensing and communication (ISAC) and
simultaneous wireless information and power transfer (SWIPT), by investigating
a new multi-functional multiple-input multiple-output (MIMO) system integrating
wireless sensing, communication, and powering. In this system, one
multi-antenna hybrid access point (H-AP) transmits wireless signals to
communicate with one multi-antenna information decoding (ID) receiver,
wirelessly charge one multi-antenna energy harvesting (EH) receiver, and
perform radar target sensing based on the echo signal at the same time. Under
this setup, we aim to reveal the fundamental performance tradeoff limits among
sensing, communication, and powering, in terms of the estimation Cramer-Rao
bound (CRB), achievable communication rate, and harvested energy level,
respectively. In particular, we consider two different target models for radar
sensing, namely the point and extended targets, for which we are interested in
estimating the target angle and the complete target response matrix,
respectively. For both models, we define the achievable CRB-rate-energy (C-R-E)
region and characterize its Pareto boundary by maximizing the achievable rate
at the ID receiver, subject to the estimation CRB requirement for target
sensing, the harvested energy requirement at the EH receiver, and the maximum
transmit power constraint at the H-AP. We obtain the well-structured optimal
transmit covariance solutions to the two formulated problems by applying
advanced convex optimization techniques. Numerical results show the optimal
C-R-E region boundary achieved by our proposed design, as compared to the
benchmark schemes based on time switching and eigenmode transmission (EMT).Comment: 30 pages, 9 figures, submitted to IEEE TCOM. arXiv admin note:
substantial text overlap with arXiv:2210.1671
Optimal Transmit Beamforming for Integrated Sensing and Communication
This paper studies the transmit beamforming in a downlink integrated sensing
and communication (ISAC) system, where a base station (BS) equipped with a
uniform linear array (ULA) sends combined information-bearing and dedicated
radar signals to simultaneously perform downlink multiuser communication and
radar target sensing. Under this setup, we maximize the radar sensing
performance (in terms of minimizing the beampattern matching errors or
maximizing the minimum weighted beampattern gains), subject to the
communication users' minimum signal-to-interference-plus-noise ratio (SINR)
requirements and the BS's transmit power constraints. In particular, we
consider two types of communication receivers, namely Type-I and Type-II
receivers, which do not have and do have the capability of cancelling the
interference from the {\emph{a-priori}} known dedicated radar signals,
respectively. Under both Type-I and Type-II receivers, the beampattern matching
and minimum weighted beampattern gain maximization problems are globally
optimally solved via applying the semidefinite relaxation (SDR) technique
together with the rigorous proof of the tightness of SDR for both Type-I and
Type-II receivers under the two design criteria. It is shown that at the
optimality, radar signals are not required with Type-I receivers under some
specific conditions, while radar signals are always needed to enhance the
performance with Type-II receivers. Numerical results show that the minimum
weighted beampattern gain maximization leads to significantly higher
beampattern gains at the worst-case sensing angles with a much lower
computational complexity than the beampattern matching design. We show that by
exploiting the capability of canceling the interference caused by the radar
signals, the case with Type-II receivers results in better sensing performance
than that with Type-I receivers and other conventional designs.Comment: submitted for possible journal publicatio
Dynamically Mitigating Data Discrepancy with Balanced Focal Loss for Replay Attack Detection
It becomes urgent to design effective anti-spoofing algorithms for vulnerable
automatic speaker verification systems due to the advancement of high-quality
playback devices. Current studies mainly treat anti-spoofing as a binary
classification problem between bonafide and spoofed utterances, while lack of
indistinguishable samples makes it difficult to train a robust spoofing
detector. In this paper, we argue that for anti-spoofing, it needs more
attention for indistinguishable samples over easily-classified ones in the
modeling process, to make correct discrimination a top priority. Therefore, to
mitigate the data discrepancy between training and inference, we propose to
leverage a balanced focal loss function as the training objective to
dynamically scale the loss based on the traits of the sample itself. Besides,
in the experiments, we select three kinds of features that contain both
magnitude-based and phase-based information to form complementary and
informative features. Experimental results on the ASVspoof2019 dataset
demonstrate the superiority of the proposed methods by comparison between our
systems and top-performing ones. Systems trained with the balanced focal loss
perform significantly better than conventional cross-entropy loss. With
complementary features, our fusion system with only three kinds of features
outperforms other systems containing five or more complex single models by
22.5% for min-tDCF and 7% for EER, achieving a min-tDCF and an EER of 0.0124
and 0.55% respectively. Furthermore, we present and discuss the evaluation
results on real replay data apart from the simulated ASVspoof2019 data,
indicating that research for anti-spoofing still has a long way to go.Comment: This work has been accepted by the 25th International Conference on
Pattern Recognition (ICPR2020
Ground state phase transition in the Nilsson mean-field plus standard pairing model
The ground state phase transition in Nd, Sm, and Gd isotopes is investigated by using the Nilsson mean-field plus standard pairing model based on the exact solutions obtained from the extended Heine-Stieltjes correspondence. The results of the model calculations successfully reproduce the critical phenomena observed experimentally in the odd-even mass differences, odd-even differences of two-neutron separation energy, and the α-decay and double β - decay energies of these isotopes. Since the odd-even effects are the most important signatures of pairing interactions in nuclei, the model calculations yield microscopic insight into the nature of the ground state phase transition manifested by the standard pairing interaction
Enhancing Generalizable 6D Pose Tracking of an In-Hand Object with Tactile Sensing
While holding and manipulating an object, humans track the object states
through vision and touch so as to achieve complex tasks. However, nowadays the
majority of robot research perceives object states just from visual signals,
hugely limiting the robotic manipulation abilities. This work presents a
tactile-enhanced generalizable 6D pose tracking design named TEG-Track to track
previously unseen in-hand objects. TEG-Track extracts tactile kinematic cues of
an in-hand object from consecutive tactile sensing signals. Such cues are
incorporated into a geometric-kinematic optimization scheme to enhance existing
generalizable visual trackers. To test our method in real scenarios and enable
future studies on generalizable visual-tactile tracking, we collect a real
visual-tactile in-hand object pose tracking dataset. Experiments show that
TEG-Track significantly improves state-of-the-art generalizable 6D pose
trackers in both synthetic and real cases
DPL: Decoupled Prompt Learning for Vision-Language Models
Prompt learning has emerged as an efficient and effective approach for
transferring foundational Vision-Language Models (e.g., CLIP) to downstream
tasks. However, current methods tend to overfit to seen categories, thereby
limiting their generalization ability for unseen classes. In this paper, we
propose a new method, Decoupled Prompt Learning (DPL), which reformulates the
attention in prompt learning to alleviate this problem. Specifically, we
theoretically investigate the collaborative process between prompts and
instances (i.e., image patches/text tokens) by reformulating the original
self-attention into four separate sub-processes. Through detailed analysis, we
observe that certain sub-processes can be strengthened to bolster robustness
and generalizability by some approximation techniques. Furthermore, we
introduce language-conditioned textual prompting based on decoupled attention
to naturally preserve the generalization of text input. Our approach is
flexible for both visual and textual modalities, making it easily extendable to
multi-modal prompt learning. By combining the proposed techniques, our approach
achieves state-of-the-art performance on three representative benchmarks
encompassing 15 image recognition datasets, while maintaining
parameter-efficient. Moreover, our DPL does not rely on any auxiliary
regularization task or extra training data, further demonstrating its
remarkable generalization ability.Comment: 11 pages, 5 figures, 8 table
An Overview on IEEE 802.11bf: WLAN Sensing
With recent advancements, the wireless local area network (WLAN) or wireless
fidelity (Wi-Fi) technology has been successfully utilized to realize sensing
functionalities such as detection, localization, and recognition. However, the
WLANs standards are developed mainly for the purpose of communication, and thus
may not be able to meet the stringent requirements for emerging sensing
applications. To resolve this issue, a new Task Group (TG), namely IEEE
802.11bf, has been established by the IEEE 802.11 working group, with the
objective of creating a new amendment to the WLAN standard to meet advanced
sensing requirements while minimizing the effect on communications. This paper
provides a comprehensive overview on the up-to-date efforts in the IEEE
802.11bf TG. First, we introduce the definition of the 802.11bf amendment and
its formation and standardization timeline. Next, we discuss the WLAN sensing
use cases with the corresponding key performance indicator (KPI) requirements.
After reviewing previous WLAN sensing research based on communication-oriented
WLAN standards, we identify their limitations and underscore the practical need
for the new sensing-oriented amendment in 802.11bf. Furthermore, we discuss the
WLAN sensing framework and procedure used for measurement acquisition, by
considering both sensing at sub-7GHz and directional multi-gigabit (DMG)
sensing at 60 GHz, respectively, and address their shared features,
similarities, and differences. In addition, we present various candidate
technical features for IEEE 802.11bf, including waveform/sequence design,
feedback types, as well as quantization and compression techniques. We also
describe the methodologies and the channel modeling used by the IEEE 802.11bf
TG for evaluation. Finally, we discuss the challenges and future research
directions to motivate more research endeavors towards this field in details.Comment: 31 pages, 25 figures, this is a significant updated version of
arXiv:2207.0485
Exercise for prevention of falls and fall-related injuries in neurodegenerative diseases and aging-related risk conditions: a meta-analysis
IntroductionNeurodegenerative diseases often cause motor and cognitive deterioration that leads to postural instability and motor impairment, while aging-associated frailty frequently results in reduced muscle mass, balance, and mobility. These conditions increase the risk of falls and injuries in these populations. This study aimed to determine the effects of exercise on falls and consequent injuries among individuals with neurodegenerative diseases and frail aging people.MethodsElectronic database searches were conducted in PubMed, Cochrane Library, SportDiscus, and Web of Science up to 1 January 2023. Randomized controlled trials that reported the effects of exercise on falls and fall-related injuries in neurodegenerative disease and frail aging people were eligible for inclusion. The intervention effects for falls, fractures, and injuries were evaluated by calculating the rate ratio (RaR) or risk ratio (RR) with 95% confidence interval (CI).ResultsSixty-four studies with 13,241 participants met the inclusion criteria. Exercise is effective in reducing falls for frail aging people (RaR, 0.75; 95% CI, 0.68–0.82) and participants with ND (0.53, 0.43–0.65) [dementia (0.64, 0.51–0.82), Parkinson’s disease (0.49, 0.39–0.69), and stroke survivors (0.40, 0.27–0.57)]. Exercise also reduced fall-related injuries in ND patients (RR, 0.66; 95% CI, 0.48–0.90) and decreased fractures (0.63, 0.41–0.95) and fall-related injuries (0.89, 0.84–0.95) among frail aging people. For fall prevention, balance and combined exercise protocols are both effective, and either short-, moderate-, or long-term intervention duration is beneficial. More importantly, exercise only induced a very low injury rate per participant year (0.007%; 95% CI, 0–0.016) and show relatively good compliance with exercise (74.8; 95% CI, 69.7%–79.9%).DiscussionExercise is effective in reducing neurodegenerative disease- and aging-associated falls and consequent injuries, suggesting that exercise is an effective and feasible strategy for the prevention of falls
Multiple sex partner behavior in female undergraduate students in China: A multi-campus survey
<p>Abstract</p> <p>Background</p> <p>China is realizing increases in women engaged in premarital sex and multiple sex partner behavior. Our aim was to examine prevalence and determinants of multiple sex partner behavior among female undergraduates in China.</p> <p>Methods</p> <p>Anonymously completed questionnaires were received from 4,769 unmarried female undergraduates, recruited using randomized cluster sampling by type of university and students' major and grade. Items captured demographic, family, peer and work influence, and student factors (major, academic performance, and sex-related knowledge and attitudes). To examine risk factors for sexual behaviors, we used multi-level logistic regression, yielding odds ratios (OR) and 95% confidence intervals (95% CI).</p> <p>Results</p> <p>Of 4,769 female students, 863 (18.10%) reported ever having sexual intercourse, and 5.31% reported having multiple sex partners (29.32% of all women having sexual intercourse). Several demographic, family, peer and work influences, and student factors (including major, performance, knowledge, and attitude toward sex) were risk factors for ever having sex. However, risk factors for multiple sex partners only included working in a place of entertainment, having current close friends that were living with boyfriends, poor academic performance, and positive attitudes toward multiple partners. These women also were more likely to practice masturbation, start having sex at a younger age, have sex with married men and/or men not their "boyfriends" at first coitus, and not use condoms consistently.</p> <p>Conclusion</p> <p>A small but important subset of Chinese female undergraduates is engaged in unprotected sex with multiple sex partners. Interventions need to target at risk women, stressing the importance of consistent condom use.</p
- …