The research evaluates the effectiveness of shuffle-based Moving Target Defense (MTD) on host and network systems using a temporal graph-based security model, T-HARM. A novel dynamic security metric, the Reward-Based Metric (RBM), is introduced to assess the impact of MTD from the defender’s perspective, capturing changes in system resilience and attacker effort. The study involves implementing shuffle-based MTD techniques, defining and integrating the new metric with existing ones, and conducting simulation-based experiments to analyze security posture over time. The results show that the dynamic metric more accurately reflects real-time security changes, and that shuffle-based MTD significantly increases attack complexity and delays system compromise, thereby enhancing overall network defense.

Air quality, both indoors and outdoors, is crucial for public health as it affects respiratory conditions and overall well-being. Machine learning (ML) techniques offer innovative solutions for monitoring and predicting air quality. However, choosing the right ML algorithms and evaluation metrics is essential for creating accurate air quality prediction models, as these choices directly impact the accuracy and reliability of the results. This study aims to explore and summarize the literature on the use of ML techniques in predicting and optimizing air quality, addressing the urgent issue of air pollution. The review analyzed papers from two electronic databases, namely Scopus and Science Direct. Information on ML techniques for predicting air quality and identifying the main sources of pollution was extracted from 26 studies. The study focuses on common ML techniques employed in air quality prediction, including classification, deep learning, regression, ensemble learning, and combinations of regression and deep learning. It also identifies the evaluation metrics used to assess the performance of these models, such as recall, root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R2). By synthesizing existing knowledge, this study provides a comprehensive understanding of the metrics researchers use to measure the overall effectiveness of ML algorithms. It serves as a benchmark for future research and guides the selection of appropriate evaluation metrics in the field of air quality prediction.

Bidirectional radio over fiber (RoF) transmission to multiple remote antenna units (RAUs) with frequency octupling is proposed in this paper. The proposed RoF system uses a dual-port Mach-Zehnder modulator (DP-MZM) and an arrayed waveguide grating (AWG) to generate millimeter-wave (mm-wave) to four different RAUs. Bit Error Rate (BER) and received optical power are key parameters used to measure the performance of the system. From the simulation results, it is shown that the proposed system achieves an acceptable performance a fiber distance of 50 km with a BER of 10-12. Furthermore, the results indicate that the dispersion-induced power penalties for both uplink and downlink transmission of all RAUs are less than 1 dB. In summary, the proposed system simplifies the RoF system by reusing wavelengths and utilizing low RoF frequency through the frequency-octupling technique.

In the modern world, wireless communications are growing very fast and changing the world of antennas. Conventional antennas are insufficient to meet the requirements in the field of wireless communications. The continuous evolution of wireless communication systems has added cost, size, bandwidth, gain, and polarization constraints to the antennas used. In this paper, the performance of the microstrip antenna is enhanced by overlapping the patch elements. A tree-shaped micro-strip antenna is presented here, in which the tree-shaped geometry emerged from five overlapping circles on the substrate. The proposed antenna could operate in the X and Ku bands. The antenna is resonant at 9.3 GHz, 10.07 GHz, 11.76 GHz, and 13.16 GHz frequencies and has various applications such as satellite communications, radar, terrestrial broadband, space communications, and amateur radio. The built antenna has an improved radiation pattern as compared to conventional antennas.

This work demonstrates the methodological steps to simulate a three-degree of freedom (DoF) delta robot arm in the Foxy Fitzroy version of Robot Operating System 2 (ROS2). The mechanical design of the delta robot was represented in the form of Simulation Description Format (SDF), translated from the customised Unified Robotic Description Format (URDF) file generated using SolidWorks to URDF Exporter after the designed mechanism had been finalised. It is necessary to use the SDF instead of URDF for delta robot simulation since this type of file format supports closed-loop linkages, one of the crucial features of a delta robot arm mechanism. The simulation of the delta robot motion was conducted in the Gazebo Robot Simulator, where the positioning of the delta robot end effector was observed when the specific force was applied to each of the robot arms. The mechanism of the delta robot behaviour on forward and inverse kinematic was then simulated to observe the positioning of the end effector toward the motion of motor rotational angle and vice-versa.