11 research outputs found
RIS-aided Real-time Beam Tracking for a Mobile User via Bayesian Optimization
The conventional beam management procedure mandates that the user equipment
(UE) periodically measure the received signal reference power (RSRP) and
transmit these measurements to the base station (BS). The challenge lies in
balancing the number of beams used: it should be large enough to identify
high-RSRP beams but small enough to minimize reporting overhead. This paper
investigates this essential performance-versus-overhead trade-off using
Bayesian optimization. The proposed approach represents the first application
of real-time beam tracking via Bayesian optimization in RIS-assisted
communication systems. Simulation results validate the effectiveness of this
scheme
A Wi-Fi Signal-Based Human Activity Recognition Using High-Dimensional Factor Models
Passive sensing techniques based on Wi-Fi signals have emerged as a promising
technology in advanced wireless communication systems due to their widespread
application and cost-effectiveness. However, the proliferation of low-cost
Internet of Things (IoT) devices has led to dense network deployments,
resulting in increased levels of noise and interference in Wi-Fi environments.
This, in turn, leads to noisy and redundant Channel State Information (CSI)
data. As a consequence, the accuracy of human activity recognition based on
Wi-Fi signals is compromised. To address this issue, we propose a novel CSI
data signal extraction method. We established a human activity recognition
system based on the Intel 5300 network interface cards (NICs) and collected a
dataset containing six categories of human activities. Using our approach,
signals extracted from the CSI data serve as inputs to machine learning (ML)
classification algorithms to evaluate classification performance. In comparison
to ML methods based on Principal Component Analysis (PCA), our proposed
High-Dimensional Factor Model (HDFM) method improves recognition accuracy by
6.8%
Design of Reconfigurable Intelligent Surfaces for Wireless Communication: A Review
Existing literature reviews predominantly focus on the theoretical aspects of
reconfigurable intelligent surfaces (RISs), such as algorithms and models,
while neglecting a thorough examination of the associated hardware components.
To bridge this gap, this research paper presents a comprehensive overview of
the hardware structure of RISs. The paper provides a classification of RIS cell
designs and prototype systems, offering insights into the diverse
configurations and functionalities. Moreover, the study explores potential
future directions for RIS development. Notably, a novel RIS prototype design is
introduced, which integrates seamlessly with a communication system for
performance evaluation through signal gain and image formation experiments. The
results demonstrate the significant potential of RISs in enhancing
communication quality within signal blind zones and facilitating effective
radio wave imaging
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment
Enhancing Bioinspired Aramid Nanofiber Networks by Interfacial Hydrogen Bonds for Multiprotection under an Extreme Environment
In
nature, many insects have evolved sclerotic cuticles to shelter
their soft bodies, which are considered as “body armor”.
For beetles, the epidermis is composed of cross-linked intertwined
fiber structures; such a fiber network structure could provide an
anti-impact function for composites. Aramid nanofibers (ANFs) are
of great interest in various applications due to their 1D nanoscale,
high aspect ratio, excellent strength and modulus, and impressive
chemical and thermal stability. In this paper, a kind of ANF network
is prepared by a layer-by-layer assembly method. The enhancing ANF
networks are developed by introducing carboxylated chitosan acting
as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs).
As a result of the formation of a nanostructure and the hydrogen-bond
interactions, the assembled C-ANF networks presented a high tensile
strength (551.4 MPa) and toughness (4.0 MJ/m2), which is
2.41 times and 32.69 times those of neat ANF networks, respectively.
The excellent mechanical properties endow C-ANF networks with distinguished
anti-impact performance. The specific dissipated energy after mass
normalization reaches 7.34 MJ/kg, which is significantly superior
to traditional protective materials such as steel and Kevlar composites.
A nonlinear spring model is also used to explain the mechanical behavior
of C-ANF networks. In addition to anti-impact protection, C-ANF networks
can realize more than 99% of UV irradiation absorption and have excellent
thermal stability. The chemical stability of C-ANF networks make them
survive in acid and alkali environments. The above characteristics
show that C-ANF networks have great application value in multiscale
protection scenarios under an extreme environment