Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Differential Relays01:20

Differential Relays

145
Differential relays are used to protect generators, buses, and transformers by comparing electrical quantities at different points. When a fault occurs, the difference in current between the two points triggers the relay to operate, opening the circuit breaker. Under normal conditions, the current entering (i1) and leaving (i2) a generator are equal. When a fault occurs, however, these currents become unequal, and the difference current flows in the relay operating coil, causing the relay to...
145
Pilot and Numeric Relaying01:21

Pilot and Numeric Relaying

87
Pilot relaying is a type of differential protection used in power systems. It compares electrical quantities at the terminals of equipment via a communication channel instead of direct relay interconnection. This method is essential for transmission lines where the terminals are far apart, typically up to 80 km for lines with 69 to 115 kV ratings. Four types of communication channels are used for pilot relaying:
87
Directional Relays01:25

Directional Relays

125
Directional relays, essential for managing unidirectional fault currents, enhance the safety and efficiency of power systems. On power lines equipped with directional relays, faults downstream (to the right) of the current transformer typically cause the fault current to lag the bus voltage by approximately 90 degrees, known as the forward direction. In contrast, upstream (left-side) faults may result in the fault current leading the bus voltage by nearly 90 degrees, termed the reverse...
125
Comparison between RL and RC circuits01:24

Comparison between RL and RC circuits

4.0K
An RC circuit consists of resistance and capacitance, while in an RL circuit, capacitance is replaced by an inductor. RL and RC circuits are first-order differential circuits that store energy. An RC circuit stores energy in the electric field, while an RL circuit stores energy in the magnetic field. When connected to a battery, an RC circuit charges the capacitor, causing the current to decrease from maximum to zero upon being fully charged. This increases the voltage across the capacitor from...
4.0K
Discrete-Time Fourier Series01:20

Discrete-Time Fourier Series

280
The Discrete-Time Fourier Series (DTFS) is a fundamental concept in signal processing, serving as the discrete-time counterpart to the continuous-time Fourier series. It allows for the representation and analysis of discrete-time periodic signals in terms of their frequency components. Unlike its continuous counterpart, which utilizes integrals, the calculation of DTFS expansion coefficients involves summations due to the discrete nature of the signal.
For a discrete-time periodic signal x[n]...
280
Fast Fourier Transform01:10

Fast Fourier Transform

348
The Fast Fourier Transform (FFT) is a computational algorithm designed to compute the Discrete Fourier Transform (DFT) efficiently. By breaking down the calculations into smaller, manageable sections, the FFT significantly reduces the computational complexity involved. Direct computation of an N-point DFT requires N2 complex multiplications, whereas the FFT algorithm needs only (N/2)log⁡2N multiplications, offering a much faster performance.
The computational efficiency of the FFT becomes...
348

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Decentralized Computation Offloading Strategy via Multi-Agent Deep Reinforcement Learning for Multi-Access Edge Computing Systems.

Sensors (Basel, Switzerland)·2026
Same author

Covert Communications in a Hybrid DF/AF Relay System.

Sensors (Basel, Switzerland)·2024
Same author

Disguised Full-Duplex Covert Communications.

Sensors (Basel, Switzerland)·2023
Same journal

RETRACTED: Zhang et al. A Novel Framework for Reconstruction and Imaging of Target Scattering Centers via Wide-Angle Incidence in Radar Networks. <i>Sensors</i> 2025, <i>25</i>, 6802.

Sensors (Basel, Switzerland)·2026
Same journal

Enhancing Unsupervised Multi-Source Domain Adaptation for Person Re-Identification via Mixture of Experts and Graph-Based Relation.

Sensors (Basel, Switzerland)·2026
Same journal

Development of an Instrumented Glove for Palmar Pressure Assessment in Kayakers.

Sensors (Basel, Switzerland)·2026
Same journal

Development and Experimental Validation of an Autonomous IoT-Based Monitoring System for Real-Time Water Quality Assessment in the Amazon River.

Sensors (Basel, Switzerland)·2026
Same journal

Semi-Supervised Adversarial Learning Framework for Controller Area Network Bus Intrusion Detection.

Sensors (Basel, Switzerland)·2026
Same journal

Smart Optimization Method for Safety Signs in Innovative Manufacturing Environments Integrating Industrial Field IoT Sensors and Knowledge Graphs.

Sensors (Basel, Switzerland)·2026
See all related articles

Related Experiment Video

Updated: Jul 11, 2025

Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells
14:12

Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells

Published on: December 11, 2021

5.3K

Performance Comparison of Relay-Based Covert Communications: DF, CF and AF.

Jihwan Moon1

  • 1Department of Mobile Convergence Engineering, Hanbat National University, Daejeon 34158, Republic of Korea.

Sensors (Basel, Switzerland)
|November 14, 2023
PubMed
Summary
This summary is machine-generated.

This study compares covert communication performance in decode-and-forward (DF), compress-and-forward (CF), and amplify-and-forward (AF) relay systems. CF or AF relays generally outperform DF relays under specific power conditions, impacting covert rate optimization.

Keywords:
amplify-and-forwardcompress-and-forwardcovert communicationsdecode-and-forwardlow probability of detectionphysical layer securityrelay

More Related Videos

Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody
09:09

Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody

Published on: September 27, 2024

464
Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy
14:04

Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy

Published on: April 25, 2021

5.6K

Related Experiment Videos

Last Updated: Jul 11, 2025

Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells
14:12

Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells

Published on: December 11, 2021

5.3K
Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody
09:09

Foreign Accent and Forensic Speaker Identification in Voice Lineups: The Influence of Acoustic Features Based on Prosody

Published on: September 27, 2024

464
Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy
14:04

Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy

Published on: April 25, 2021

5.6K

Area of Science:

  • Wireless communication systems
  • Information theory
  • Signal processing

Background:

  • Covert communication is crucial for secure data transmission.
  • Relay systems enhance communication range and reliability.
  • Optimizing covertness while maintaining communication rates is a key challenge.

Purpose of the Study:

  • To analyze and compare the performance of decode-and-forward (DF), compress-and-forward (CF), and amplify-and-forward (AF) relay systems for covert communications.
  • To optimize power allocation between public and covert messages to maximize covert rates, considering the relay's detection error probability (DEP).
  • To conduct a delay-aware comparison of DF, CF, and AF systems and examine their asymptotic behaviors.

Main Methods:

  • Investigated covert communication performance across DF, CF, and AF relay architectures.
  • Optimized power distribution to maximize covert rate while minimizing DEP at the relay.
  • Derived closed-form covert rates and performed delay-aware comparisons.
  • Analyzed system performance under various channel models and asymptotic conditions.

Main Results:

  • Compress-and-forward (CF) or amplify-and-forward (AF) relays generally outperform decode-and-forward (DF) relays at high source transmit power or low relay transmit power.
  • The performance hierarchy among DF, CF, and AF relays is sensitive to system parameters like processing delay, quality of service for public messages, and DEP threshold, especially at high relay transmit power.
  • Numerical results validated the performance comparisons across different channel models.

Conclusions:

  • The choice between DF, CF, and AF relay systems for covert communications depends significantly on power constraints and system parameters.
  • Optimal power allocation strategies are essential for maximizing covert rates in relay-assisted covert communication systems.
  • Further research can explore more complex relaying protocols and realistic channel conditions for enhanced covert communication security.