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ABSTRACT Phased Array Systems (PASs) are extensively used in radar and telecommunication systems for diverse applications, including military surveillance and wireless broadband communication. Besides, they are becoming increasingly indispensable in modern applications such as multi‐function phased array radars for weather monitoring and aircraft tracking or high‐throughput satellite systems, which aim to provide fast broadband connectivity in remote areas. Despite the numerous advantages of phased array systems with RF phase shift, including high signal‐to‐noise and signal‐to‐interference ratios, as well as low complexity, they present a few limitations, including high cost and large chip areas. The cost and size of PASs are mainly dependent on the RF phase shifters, which are essential to their operation. This article describes the different types of phase shifters (mechanical, ferromagnetic/magnetic, electromechanical, and electronic). It compares their performance metrics, highlighting that electronic phase shifters are the most common type used in modern PASs. In this regard, a comparative study of different subcategories of electronic phase shifters, such as the switched‐type, reflective‐type, loaded‐transmission line, and vector‐sum phase shifters, are explored along with their advantages, drawbacks and state‐of‐art techniques used to address their limitations. Therefore, this article may serve as a reference for research milestones on RF phase shifters. [ABSTRACT FROM AUTHOR]

This study proposes a compact, low-profile, four-port dual-band monopole multiple-input-multiple-output (MIMO) antenna array for unmanned aerial vehicle (UAV) communication systems. Each monopole antenna of the array features a modified T-shaped radiator configuration and is printed on a Rogers RT5880 substrate with compact dimensions of 134.96 mm × 134.96 mm × 0.8 mm. A four-element square MIMO configuration with sequential 0°, 90°, 180°, and 270° rotations was integrated smoothly into the UAV body. A prototype of the MIMO array was fabricated and experimentally evaluated, with measured results showing a close correlation to simulated results. The proposed dual-band monopole antenna demonstrated one of the widest impedance bandwidths of 46.15% at 2.4 GHz (2.04 to 3.25 GHz) IEEE 802.11b and 31.85% at 5.8 GHz (5.37 to 7.38 GHz) IEEE 802.11a on a thin 0.0064 λo substrate while achieving high transmission efficiency. The isolation of the proposed four-port MIMO design was measured at 23 dB at 2.4 GHz and 19 dB at 5.8 GHz. The MIMO array's total efficiency of each monopole antenna was measured at 96% at 2.4 GHz and 89% at 5.8 GHz. The design has measured diversity parameters such as an ECC below 0.01 and a DG of approximately 10. Based on these results, the proposed design suits the UAV communication system. [ABSTRACT FROM AUTHOR]

This study examines the high‐power microwave (HPM) jamming effect on software‐defined radio (SDR). Following theoretical analysis and formula derivation of the single‐tone jamming, the HPM jamming effect is validated using an SDR platform. Jamming is relatively easily achieved when the jamming signal falls within the communication system's frequency band. For out‐of‐band signals, a higher jamming signal ratio is needed, with the receiving front‐end device's nonlinearity causing the jamming. This study highlights the susceptibility of broadband receivers to HPM jamming, demonstrating that even out‐of‐band threats cannot be disregarded in wideband receiver designs for strong signals such as HPM. [ABSTRACT FROM AUTHOR]

To help with the critical nurse staffing shortages in hospitals worldwide, robotic assistants are designed to handle frequently required tasks in the digital operating room (DOR), such as the guidance of the laparoscopic camera. To enable fluent collaboration between robots and clinicians, an intuitive and efficient communication interface is needed to allow for interaction using natural language. However, the demanding requirements of the surgical domain make it challenging to develop suitable solutions. A variety of different vocabulary or phrases may be used for expressing the same command. At the same time, surgical workflows may be highly dynamic - especially in emergency situations - and thus the system must be able to grasp the user's intent both quickly and with high accuracy. This is especially true as only some clinicians may be authorized to request certain tasks, depending on their rank or field of expertise. To solve these challenges, our proposed communication system uses the fine-tuned deep learning model to recognize the speaker information, and the robot assistant takes action only when it detects the commands from the responsible clinician. Also, our proposed conversational functions enable the finetuned large language models to understand the current natural language command given previous command history. In this work, we present a communication system to recognize the speaking person and understand the intent of conversational commands quickly and accurately. [ABSTRACT FROM AUTHOR]

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In this paper, we consider the steps to be followed in the analysis and interpretation of the quantization problem related to the C 2 , 8 channel, where the Fuchsian differential equations, the generators of the Fuchsian groups, and the tessellations associated with the cases g = 2 and g = 3 , related to the hyperbolic case, are determined. In order to obtain these results, it is necessary to determine the genus g of each surface on which this channel may be embedded. After that, the procedure is to determine the algebraic structure (Fuchsian group generators) associated with the fundamental region of each surface. To achieve this goal, an associated linear second-order Fuchsian differential equation whose linearly independent solutions provide the generators of this Fuchsian group is devised. In addition, the tessellations associated with each analyzed case are identified. These structures are identified in four situations, divided into two cases (g = 2 and g = 3) , obtaining, therefore, both algebraic and geometric characterizations associated with quantizing the C 2 , 8 channel. [ABSTRACT FROM AUTHOR]

Copyright of China Medical Education Technology is the property of China Medical Education Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective At present, in urban rail transit communication systems, there commonly exist the problems like the deficiencies of poor openness and difficult interconnection between the subsystems and low level of digitization and intelligence. In order to further improve the operation and maintenance level of the communication system, it is necessary to develop an intelligent communication operation and maintenance platform. Method The construction demand of an intelligent communication operation and maintenance platform is analyzed, and the 5-level functions of the above platform technical architecture for urban rail transit are expounded. The technical architecture of the platform based on multi-dimensional collaborative collection and calculation is further set up, and the intelligent diagnosis model of the platform is emphatically introduced. With Nanning urban rail transit Line 4 as the study case, the practical application result of the platform on the line is analyzed. Result & Conclusion The platform can realize equipment monitoring, equipment early warning, equipment diagnosis, mobile monitoring and other functions, improving the efficiency and quality of the communication system operation and maintenance. It can provide technical support for the transformation of the communication equipment from planned repair to status repair as well.

As the main equipment for earthquake disaster rescue and reconnaissance battlefield, the robustness of UAV swarm communication system is an important index of destruction resistance. In this paper, we model the UAV swarm communication system with the help of complex dependency network theory, introduce the relative network effectiveness ratio as an index of the overall robustness of the communication system network, which accurately reflects the interdependence between nodes, and provides a new perspective for evaluating the robustness of the communication system under the target attack. A new perspective is provided for assessing the robustness of communication systems under target attack. Based on the classical M-L model and the load redistribution strategy with dynamic information, we establish the dependent homogeneous ER-ER and heterogeneous ER-BA network models, consider the characteristics of the degree of dependent nodes in the two-layer network for target attack, and analyze the dynamic process of their cascading failure under the attack, as well as the influence of the characteristic parameters, such as the probability of connecting edges of any two nodes, the average degree and the capacity coefficient, on the overall robustness of the communication network. It is shown that network robustness and network dependency strength are negatively correlated, and a reduction of 52.09% to 72.9% dependency strength can be considered in the cascade failure process to resist more serious communication network collapse. For isomorphic networks, the difference in dependency patterns has a greater impact by reducing the overall robustness of RL and AL compared to DL by 9.25% and 15.95%, respectively.

Objective The health of metro communication system has a direct bearing on the efficiency and safety of metro operation. In view of the problems such as one-sided evaluation results and subjective evaluation criteria in current health evaluation method for metro communication systems, it is necessary to construct a method that can scientifically and accurately evaluate the operation status and health of the metro communication system. Method A dynamic health evaluation method based on random forests algorithm is proposed, and a communication health inspection is conducted in combination with deep learning. The evaluation index system is designed to collect the corresponding data. The mixed label method is used to determine the label and calculate the importance of each index when the label (true health degree) is not clear. The health degree of each subsystem of communication system is calculated according to the index weight and the index self scoring standards established by experts, which properly incorporates the influence of experts' knowledge. Based on the maintenance data of Chengdu Metro, the method is tested and verified. Result & Conclusion The test verification results show that with the above method, effective index importance can be obtained and the health of metro communication system can be reasonably evaluated.

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Urban Mass Transit is the property of Urban Mass Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Frequency-selective filters are usually required at the receiving end of a communication system to change the frequency range of a band-pass filter (BPF), which is used to extract the broadcast signal. In this study, we have designed such frequency-selective filters using a novel bulk-driven current differential transconductance amplifier (BDCDTA) as its fundamental building block. This BDCDTA is first used to create a biquad filter, and the designed filter is then reconfigured for frequency selection. The proposed frequency-selective filter structures have the capability of providing a constant gain based on the communication system's requirements. The suggested structures with CMOS 180 nm technology parameters are validated using PSPICE and the Cadence Virtuoso design environment. The theory is confirmed by pre and post-layout simulation. PVT corner and Monte-Carlo analysis demonstrate its applicability for a broad range of applications and provide a range for its use under various conditions. This design is suitable for low voltage and low power applications due to the bulk-driven transistors, and the suggested structures are designed especially for medium wave communication and biomedical signal processing. [ABSTRACT FROM AUTHOR]

Objective In response to the situation where historical optical power data in metro communication systems is missing despite the sufficient historical related data, an optical power prediction method based on double pooling multilayer perceptron model is proposed. Method The structure and prediction principles of the multilayer perceptron model and the double pooling multilayer perceptron model are introduced. Based on detection data from the Chengdu Metro communication system, experimental comparative analysis is conducted on the prediction results of different models, as well as the prediction results of the double pooling multilayer perceptron model under different variables. Result & Conclusion The double pooling multilayer perceptron model demonstrates good prediction accuracy. In facing the variability of environmental information and the repetitiveness of time sequence information, the model can utilize maximized-pooling (Maxpooling) and average-pooling (Avgpooling) separately for feature extraction, effectively predicting input optical power with data information. The model fully considers the relevant influencing factors on the input optical power of metro communication system and the characteristics of data mutation, effectively addressing the problem of frequent and unpredictable optical power fluctuations.

The aim of the article is to study the communication system of enterprises and organizations, to define its main components, interconnection and interaction, as well as its role in the process of ensuring an effective management process. In modern conditions, the effective functioning of enterprises and organizations is impossible without an established system of information and communications management. The performance of managerial functions is accompanied by information exchange both within the organization and externally. It is determined that the organization’s communication system contains subsystems of internal and external communications that provide information exchange within the organization and outside of it. Within these subsystems, social, technical, information and managerial subsystems, their constituent elements and characteristics are allocated. The internal communication system of the enterprise is designed to provide access to information in the process of making managerial decisions, while maintaining the optimal level of information protection. In addition, its further purpose is to create a favorable psychological climate in the team, increase the degree of staff involvement and loyalty, and overcome resistance to changes in the organization. The system of external communications is designed, first of all, to ensure the possibility of communication influence on external stakeholders, as well as effective circulation of information flows and information security of the enterprise. A conclusion is made regarding the need to take into account the influence of all factors and conditions of the internal and external environment, the formation of a complex of information transfer methods and tools, the optimization of communication channels, which will allow the most effective communication influence on target audiences.

[Introduction] Numerous equipment of offshore wind power projects is located on the ocean, and the inconvenient transportation makes operation and maintenance difficult. It is extremely important for offshore equipment information to be delivered to land quickly, without delay, and safely. In view of the special needs of the communication system, a communication system scheme for offshore wind farms based on 5G technology is proposed. [Method] First, a PTN+ integrated small base station with large signal coverage and strong reliability was built, and then the 5G integrated small base station with the PTN gateway were integrated to achieve fast and convenient 5G signal coverage through broadband PTN access. The 5G network with specific bandwidth improved the security of the communication system. [Result] After the completion of the 5G communication system based on PTN+ integrated small base station, IP transmission based on optical transmission, supporting multiple services and using specific bandwidth can be realized. This system can help plan and sort out the wind turbine subsystems, realize all-round signal coverage inside the wind turbine, and can quickly and safely transmit the operation status and data of wind turbines, offshore booster stations and other equipment to the onshore operation and maintenance center. This system can solve the problem of difficult real-time secure transmission of wind turbine multi-subsystems and multi-services. [Conclusion] The 5G communication system research improves offshore wind power communication, and uses specific bandwidth and emerging technologies to realize the timeliness and reliability of communication in offshore wind farms and improve the communication efficiency of offshore operation and maintenance personnel in offshore wind farms. It meets the communication requirements of offshore equipment in offshore wind power projects and is expected to be applied in engineering.

Radar communication systems have been widely used for various applications, including military surveillance, weather monitoring, and air traffic control. This research focuses on the concept of simple radar communication systems, which offers an accessible and practical solution for short-range communication needs. This aim of this research is to explore the fundamental principles and components of simple radar communication systems, how radar works by emitting radio frequency (RF) waves and analyzing their reflections to detect objects and gather information about their range, velocity, and direction. The architecture of a simple radar communication system which includes the transmitter, receiver, and signal processing components were used to execute the project. The research also addresses the challenges associated with interference, multipath propagation, and signal processing techniques to mitigate these issues in simple radar communication systems. This project aims to critically the design and construct a simple radar communication system which include an Arduino nano, an SG90 servo motor, an HY-SRF05 ultrasonic sensor, a 1602 LCD display, switches, LED’s, Resistors, Lithium-ion batteries, boost converter and RF modules and its adapters. Radar communication systems employ the same basic principles as traditional radar systems, which are primarily used for object detection, ranging, and tracking. However, in the case of radar communication, the transmitted signals contain data or information that is intended for communication purposes. [ABSTRACT FROM AUTHOR]

Background: Blockchain technology has better security and immutable features, which are beneficial for healthcare data management. Decentralisation data management allows better sharing of medical images between units and departments. Objectives: The objectives of this study were to determine the cost of adopting the blockchain-based system for medical images and the cost-benefit analysis for five years of adoption of this technology at a district hospital in Malaysia. Methodology: Data regarding the yearly costs and workload for 2016 until 2018 were collected from a district hospital in Malaysia. The cost of blockchain implementation was obtained from a company that developed this technology. The cost-benefit analysis was done using the capital budgeting method for five years of this technology adoption. Sensitivity analysis was done to assess uncertainty conditions during this adoption. Results: The total yearly cost of Radiology Unit for 2018 was MYR490,168.96. The cost for adopting blockchain technology was MYR80,000 for the software, MYR115,000 for upgrading the assets and yearly maintenance cost was MYR16,000. The total present value of net benefits for five years of technology adoption was MYR865,295.01. Sensitivity analysis shows that consumables cost-saving is the most sensitive variable. Most pessimistic situation analyses showed positive net benefits. Conclusion: The adoption of blockchain technology in managing medical images offers numerous benefits to public hospitals in Malaysia. Investment in this technology can provide a good return to the organisation. [ABSTRACT FROM AUTHOR]

Copyright of Urban Mass Transit is the property of Urban Mass Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Southern Energy Construction is the property of Southern Energy Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article addresses the issue of current and critical protections for applications for 4G and 5G mobile phones. The objective of the article is to provide an overview of the threats to 4G and 5G mobile communication networks and to analyze the variables used in conjunction with core and security methods. The research work uses a review of the literature to provide an overview of the threats to 4G and 5G mobile communication networks. The research also analyzed the variables used in conjunction with core and security methods. The research presents an overview of the threats to 4G and 5G mobile communication networks, including privacy attacks, behavioral attacks, space attacks, and authentication attacks. The authors also provide an overview of three types of cases, including road signs, officers, and road signs. The analysis of variables used in conjunction with core and security methods is unclear, often summarizing security. The authors conclude that there is a need for improved protections for applications for 4G and 5G mobile phones. They also suggest that further research is needed to better understand the variables used in conjunction with core and security methods. [ABSTRACT FROM AUTHOR]

Communication blackouts during the atmospheric reentry phase are a significant challenge, as flight data are lost due to interruptions caused by plasma gas generated by aerodynamic heating. This study explores a novel mitigation method using an air film, a thin insulating coolant layer on the surface. The researchers successfully reduced the reentry blackout by employing a gas injection system. Through a coupled approach using computational fluid dynamics and a frequency-dependent finite-difference time-domain method, the plasma flow properties and electromagnetic propagation were analyzed around a test model in a wind tunnel in DLR (German Aerospace Center). The numerical results indicated that the injected nitrogen gas formed an insulating air film layer on the surface. The thin layer advected backward, maintaining a low temperature without ionization, and covered the object in the wake region. The electromagnetic waves propagated and reached a distant area because the electron density was low. It means that the air film layer acted as a propagation window for the telecommunication waves. Thus, communication blackouts will be avoidable because electromagnetic waves can transmit through the air-film layer. It concluded that the air film effect, developed as a thermal protection technique, is a novel mitigation scheme for reentry blackouts. [ABSTRACT FROM AUTHOR]

End of 2019 had seen global spread of the deadly coronavirus (SARS-CoV-2) pandemic, which kills people, puts a large portion of the world in danger, and poses a serious threat to all of the world's nations. Leading medical professionals are working extremely hard to identify the virus, develop treatments for it, and create the vaccines that are required to stop and limit its spread. This study intends to develop a low-cost electronic health system to observe patients with covid infections and lessen the work required of clinicians. An enhanced approach for remote health monitoring in hospitals or detention facilities is offered by the internet of things (IoT). The IoT keeps and displays the patient's medical data via a web browser or through specialized apps that offer remote treatment once the sensors collect it. When a patient is in danger, the system offers immediate action to send alarms by email and SMS and to rapidly provide drugs to the patient. Doctors will be updated on each patient's condition thanks to this message. [ABSTRACT FROM AUTHOR]

This manuscript presents an experimental study of Quadrature Chaos Shift Keying (QCSK) as a means to tighten the physical layer security of Internet of Things (IoT) communication. Our study examines the characteristics and operational aspects of chaos oscillators, prioritizing low-power functionality, resilient chaotic oscillations, and resistance to parameter variations and noise. This study emphasizes the key role of chaos oscillators in enhancing IoT security, showcasing their potential to ensure data integrity. The findings elucidate the dynamics and synchronization stability of the selected oscillators, providing insights into their suitability for secure communication systems. This comprehensive analysis contributes to advancing secure communication methodologies for the expanding landscape of wireless sensor networks in the Internet of Things, underscoring the significance of chaos oscillators in ensuring robust and secure data transmission. [ABSTRACT FROM AUTHOR]

The requirement for a secure emergency communication system has become imperative in tandem with the industrial revolution. Additionally, the development of technology has led to increasingly robust penetration techniques that pose a threat to communication system security, leaving data vulnerable to unwanted third parties. This paper introduces a novel, powerful security approach that ensures a secure emergency communication system. Moreover, this research focuses on several cryptographic techniques among various symmetric and asymmetric ciphers, including advanced encryption standards, substitution, and transposition. The article presents an affordable and secure communication system that can transmit data over long distances with low power consumption using long-range technology. This system features a unique function that transmits updated locations, directing rescuers to the designated location. [ABSTRACT FROM AUTHOR]

Physical situations that are duplicated in virtual settings are what the term ''digital twin'' refers to. Utilizing the Internet of Things and sensors to improve microgrid operation, the Microgrid Digital Twin (MGDT) exhibits bidirectional data sharing and sophisticated communication characteristics. Smart grid functionality is enhanced, limits are set in real-time, and data is securely stored by MGDT. It directs the planning and execution phases of microgrid operations. Concurrently, industry and transportation innovation is propelled by the Industrial Revolution. AI-driven ground-dependent controls, communication systems, and sensors are essential for breakthroughs in unmanned vehicle safety. This abstract clarifies how important digital twins more specifically, MGDTs are to system operations optimization. In addition to highlighting technological advancement and the use of AI to ensure the safety of unmanned vehicles, it provides insights into the potentially revolutionary applications of digital twins across a range of industries.

Research Question: The paper deals with the analysis of the elements of the communication system in the process of digitalization of the national testing process in the Republic of Serbia. Motivation: National testing represents an important segment of education in most countries. Considering that it involves a large number of stakeholders and activities, innovations based on the implementation of new technologies are complex and require significant efforts and resources for their implementation. The digitalization of national testing in Serbia, in addition to the development of software and organizational solutions, is accompanied by the development and implementation of a communication system aimed at facilitating the acceptance of innovations by all participants. This paper addresses the analysis of the efficiency of the elements of the communication system and satisfaction of stakeholders with them, at the final exam at the end of primary education in the Republic of Serbia. Idea: The paper aims to describe a successful communication system implemented to support the process of national testing digitalization. Effective communication is essential due to the large number of participants involved in the process and should ensure national testing effectiveness and transparency. Data: For the analysis of the satisfaction of two stakeholder groups with the highest interest and influence in the process of conducting the final exam, data obtained from surveys conducted in 2021, 2022, and 2023 were used. Each year, the questionnaire was completed by over 900 primary school principals and over 8,000 parents of final-grade pupils. Tools: In the research, a questionnaire specifically designed for two stakeholder groups - primary school principals and parents of final-grade pupils was used. Statistical analysis was performed using SPSS software. Descriptive statistics and correlation analysis were employed. Findings: The research has found that high satisfaction among key stakeholders (primary school principals and parents) is achieved through a carefully designed and implemented communication system, which includes an internet portal, written and video instructions, as well as direct support from trained and expert individuals. The communication system element that has the greatest impact on principals' satisfaction is the administrative portal, while for parents, it comprises all instructions prepared for carrying out activities. Contribution: This paper expands on existing research related to the digitalization of national testing and highlights the key elements of the communication system to enhance participant satisfaction in the process.

There is an increasing demand for data with the development of the world, and various fiber optic multiplexing techniques have become an important research direction to improve transmission capacity. However, the transmitted signals are subject to great interference due to mode coupling and mode dispersion, which require multiple-input multiple-output (MIMO) digital signal processing techniques to restore the quality of the transmitted signals. In this paper, a novel MIMO detector is designed using an adaptive learning recurrent neural network and successfully implemented in a mixed wavelength-division-mode-division-multiplexing (WDM-MDM) optical transmission system, and its performance is compared with that of the forced-zero detector and the minimum-mean-square-error detector. The results show that the introduction of an adaptive machine learning model in MIMO detection for WDM-MDM optical transmission systems can significantly improve the quality of the transmitted signals and achieve better performance than other MIMO detection algorithms while maintaining a faster computational speed and a lower number of parameters.

This research explores the methods of assessing airline passenger satisfaction through surveys and analyzing factors that are strongly linked to whether a passenger is satisfied or dissatisfied. The aim is also to investigate if it is possible to predict passenger satisfaction levels. The dataset used in this study comes from a Kaggle dataset titled "Airline Passenger Satisfaction," which includes 223,690 records with 23 measurement variables and 1 response variable. It identifies three key factors critical to airline service improvement: delays, online boarding, and class. Airlines can enhance their service offerings by focusing on these areas as air travel activities pick up. Specifically, online boarding is highlighted as a significant factor in reducing the need for manual check-ins and waiting in queues, thereby providing a faster and more efficient process. Furthermore, the study's analysis of categorical data and its correlation with satisfaction levels yields important insights into customer preferences within the airline industry. The differentiation between loyal and disloyal customers, as visualized in the study, shows that many loyal customers are dissatisfied. This points to the fact that loyal customers, despite their overall satisfaction, have faced varying levels of service quality.

This study proposes a compact, low-profile, four-port dual-band monopole multiple-input-multiple-output (MIMO) antenna array for unmanned aerial vehicle (UAV) communication systems. Each monopole antenna of the array features a modified T-shaped radiator configuration and is printed on a Rogers RT5880 substrate with compact dimensions of 134.96 mm × 134.96 mm × 0.8 mm. A four-element square MIMO configuration with sequential 0°, 90°, 180°, and 270° rotations was integrated smoothly into the UAV body. A prototype of the MIMO array was fabricated and experimentally evaluated, with measured results showing a close correlation to simulated results. The proposed dual-band monopole antenna demonstrated one of the widest impedance bandwidths of 46.15% at 2.4 GHz (2.04 to 3.25 GHz) IEEE 802.11b and 31.85% at 5.8 GHz (5.37 to 7.38 GHz) IEEE 802.11a on a thin 0.0064 λo substrate while achieving high transmission efficiency. The isolation of the proposed four-port MIMO design was measured at 23 dB at 2.4 GHz and 19 dB at 5.8 GHz. The MIMO array’s total efficiency of each monopole antenna was measured at 96% at 2.4 GHz and 89% at 5.8 GHz. The design has measured diversity parameters such as an ECC below 0.01 and a DG of approximately 10. Based on these results, the proposed design suits the UAV communication system.

Copyright of HiSTOReLo: Revista de Historia Regional y Local is the property of Universidad Nacional de Colombia, Centro Editorial Facultad de Ciencias Humanas y Economicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The modern electric power grid, known as the Smart Grid, has fast transformed the isolated and centrally controlled power system to a fast and massively connected cyber-physical system that benefits from the revolutions happening in communications (such as 5G/6G) and the fast adoption of Internet of Things devices (such as intelligent electronic devices and smartmeters). While the synergy of a vast number of cyber-physical entities has allowed the Smart Grid to be much more effective and sustainable in meeting the growing global energy challenges, it has also brought with it a large number of vulnerabilities resulting in breaches of data integrity, confidentiality, and availability. False data injection (FDI) appears to be among the most critical cyberattacks and has been a focal point of interest for both research and industry. To this end, this article presents a comprehensive review of the recent advances in defence countermeasures of FDI attacks on the Smart Grid. Relevant existing works of literature are evaluated and compared in terms of their theoretical and practical significance to Smart Grid cybersecurity. In conclusion, a range of technical limitations of existing false data attack detection research is identified, and a number of future research directions are recommended. [ABSTRACT FROM AUTHOR]

Background. The modern development of the mining industry is characterized by the search for new mining technologies, increasing the complexity, depth, scale of workings and the danger of work, which leads to the search for approaches in building information and communication systems with increased functionality, namely, with the possibility of combining into a single system of mining automation tools, sensors, tunneling equipment, communication equipment, navigation, controls, equipment operating in an emergency situation. Since most underground facilities can be considered quasi-one-dimensional (mines, subways, sewers), transmission lines laid along tunnels can be effectively used to organize data transmission in them. Aim. Consider the physical side of the operation of the information and communication system in the medium and high frequency ranges. Methods. The dependence of the field strength in a tunnel with single-wire and bifilar lines laid in the tunnel was obtained using electrodynamic modeling by the finite element method. Results. The values of attenuation in workings with different medium parameters and attenuation dependences obtained experimentally in a coal mine are given. On average, the signal attenuation is 15 dB per 1 km. Conclusion. A digital medium-wave system based on bifilar lines has significant advantages when deployed over VHF communication systems. It can be used as a base, and if necessary, supplemented with VHF technologies (Bluetooth, Wi–Fi), for example, for personnel using an explosion-proof smartphone, and in areas where increased throughput is required, in places of active mining operations in mines and concentration of technological equipment and personnel.

Non-orthogonal signal-based systems are a type of communication system that uses signals that are not mutually perpendicular (i.e., not orthogonal) to transmit information. These types of systems can increase the spectral efficiency of communication systems by allowing for more data to be transmitted in the same bandwidth. Groups of signals with non-orthogonal waveforms can increase spectral efficiency, but they also increase the potential for interference. Spectrally efficient frequency division multiplexing (SEFDM) is a well-studied waveform that was originally proposed for use in wireless systems but has since found application in millimeter wave communications at 60 GHz, optical access network architecture, and long-distance optical fiber transmission. However, non-orthogonal signal-based systems are also more susceptible to interference from other sources, which can degrade the quality of the transmitted signal. To address this problem, this paper suggests using fuzzy learning techniques to cancel out interference and improve the signal-to-noise ratio. Fuzzy learning is a type of machine learning that uses fuzzy logic (FL) to handle uncertainty and imprecision in data. By using FL techniques to cancel out interference, the non-orthogonal signal-based optical communication (OC) system could potentially achieve better performance in noisy environments. Overall, this research topic has the potential to contribute to the development of more efficient and reliable OC systems that can operate in challenging environments.