Communication Equipment Research Articles

A High Step-Down SiC-Based T-Type LLC Resonant Converter for Spacecraft Power Processing Unit

A spacecraft power processing unit (PPU) is utilized to convert power from solar arrays or electric batteries to the payload, including electric propulsion, communication equipment, and scientific instruments. Currently, a high-voltage converter is widely applied to the spacecraft PPU to improve power density and save launch weight. However, the high voltage level poses challenges such as high step-down ratios and high power losses. To achieve less conduction loss, a SiC-based T-type three-level (TL) LLC resonant converter is proposed. To further broaden the gain range and achieve high step-down ratios, a variable frequency and adjustable phase-shift (VFAPS) modulation scheme is proposed. Meanwhile, the steady-state time-domain model is established to elaborate the operation principles and boundary conditions for soft switching. Furthermore, the optimal resonant element design considerations have been elaborated to achieve wider gain range and facilitate easier soft switching. Furthermore, the numerical solutions for switching frequency and phase shift (PS) angle under each specific input could be figured out. Finally, the effectiveness of this theoretical analysis is demonstrated via a 500-W experimental prototype with 650∼950-V input and constant output of 48-V/11-A.

Ternary nano-composite wireless ammonia sensor based on Polyaniline/CuTsPc/AgNPs for food intelligent packaging

The integration of gas sensing unit and low-cost wireless communication equipment enables real-time detection of various environmental gases, which is of great significance for food safety, medical diagnosis and environmental monitoring. In this study, copper phthalocyanine powder (CuTsPc) was prepared by high temperature solid phase melting technology. Ternary ammonia sensors with exceptional sensitivity to ammonia and conductivity were successfully fabricated by growing polyaniline/copper phthalocyanine/silver nanoparticles (PANI/CuTsPc/AgNPs) composites on polyethylene terephthalate films by in-situ polymerization. The morphology and composition of the films were characterized by FTIR, XRD and SEM, respectively. The ammonia sensing performance of the films at room temperature was systematically investigated. It is found that the flexible PANI/CuTsPc/AgNPs gas sensor exhibited rapid response time (61 s), fast recovery time (19 s), low theoretical detection limit (0.234 ppm), high response value (3.6 towards 500 ppm NH3), and excellent stability at room temperature. These remarkable response characteristics can be attributed to the synergistic effect between protonic acid-doped PANI, CuTsPc derivatives with an electron-withdrawing group, and AgNPs possessing both chemical sensitisation and electron sensitisation. Finally, the sensor material was transformed into a label antenna pattern as well as sensor transducer through series and parallel antenna loop access methods to create a wireless sensor system based on near-field communication (NFC). This system can offer real-time sensing and monitoring of changes in food packaging environment by non-contact recognition way, making it highly promising for future applications in intelligent packaging.

A waste extended input-output-based Transformer-LSTM method for analyzing hazardous waste reduction patterns: A case study of shanghai

Population growth, economic development, and industrialization have resulted in a notable surge in the hazardous waste (HW) generation, consequently leading to adverse effects on human health and environmental safety. In this work, a Waste Extended Input-Output-based Transformer-Long Short-Term Memory (WEIO-TL) method was developed to simulate the HW generation patterns of various economic industries in the supply chain and generate the desired strategies for reducing HW generation. The WEIO-TL method was applied to Shanghai to identify its HW reduction path and potential by 2035. Multiple scenarios were designed to investigate the impacts of different degrees of economic and technological development on HW generation. The primary results indicated that the economic proportion of each key industry and the technological innovation capability were the main factors influencing the HW generation in Shanghai. The six key industries identified by the WEIO were the chemical industry (CI), other services (OS), transportation equipment (MTE), computers, communication, and other electronic equipment (MCCOEE), wholesale and retail trades (WRT), and construction (C). HW generation would peak at 1570.9 kt in 2025 and subsequently decrease to 949.0 kt by 2035 under the optimal scenario based on the optimal TL model (R2 and RMSE values of 0.976 and 5.968), associated with industry structure optimization (i.e., part of high-polluting industries would be shifted to service) and technological innovation capability improvement. The results of the study will serve as a theoretical foundation to guide other cities toward achieving "zero waste."

A hierarchical LFFC control scheme for underactuated unmanned surface vessels based on unreliable communication interaction

This article investigates the leader-follower formation-containment (LFFC) control issue of underactuated unmanned surface vessels (USVs) system subject to unreliable communication interaction and the external disturbances. Firstly, an adaptive control scheme is established for the leaders to track the desired trajectory associated with preset formation configuration. Subsequently, by means of convex hull theory, a formation-containment control algorithm is developed to guide the followers into the specific area generated by the leaders. Nevertheless, the communication interaction among USVs is frequently unreliable, which is constrained by communication distance, equipment quality, and indeterminate cyber-attack. Worse still, this unreliability will magnify the unpredictable impact on system stability. Moreover, the signals generally undergo multilevel transmission from virtual leader to followers under LFFC structure, which will result in the amplification of unreliable ratio during the information transmissions. To address the aforementioned issues, an online-update auxiliary signal is constructed through the quasi-sliding mode manifold, which can suppress the impact of unreliable communication interaction. Theoretical analysis and numerical simulations are demonstrated to verify the feasibility and validity of the proposed control strategies.

Intelligent patrol inspection of low code enabled electric power communication equipment based on digital transformation

Intelligent patrol inspection of low code enabled electric power communication equipment based on digital transformation

Microwave absorption, thermal and mechanical properties of amorphous nano carbon doped aluminium nitride composite ceramics

Low-cost amorphous nano-carbon (ANC) was employed as an absorbent to modify the microwave performance of AlN ceramics (AlN-4 wt% Y2O3-x wt% C, x = 0, 2.0, 3.8, 3.9, 4.0) via hot-pressing sintering, and the thermal and mechanical properties were also investigated. With the increase of ANC content from 0 to 4.0 wt%, the relative density of AlN composite decreases from 3.28 g cm−3 to 3.16 g cm−3 when sintered at 1800 °C for 2 h, and with the increase of sintering temperature from 1700 °C, the density of the 4.0 wt% ANC doped AlN composite presents trend of increase and reaches the maximum value of 3.16 g cm−3 at 1800 °C and then decreases. The XRD pattern shows that the composites are composed of AlN and Y–Al–O (YAG, YAP, YAM et al.) phases. SEM results indicate that average grain sizes for AlN and secondary phases gradually decrease with increasing carbon content, suggesting inhibited grain growth due to ANC addition. No obvious changes in phase constitution nor intensity changes were detected with the increase in carbon content and sintering temperature. As the carbon content increases from 0 to 4.0 wt%, the dielectric constant gradually increases from ∼9 to 13.89 at 10 GHz, the dielectric loss gradually increases from the vicinity of 10−3 to 0.38 at 10 GHz, and the reflective loss decreases from −27.92 dB to −49.40 dB, the thermal conductivity of the AlN-ANC composite decreases from 116.63 W m−1 K−1 to 50.13 W m−1 K−1. In addition, with 4.0 wt% ANC addition, the dielectric constant, dielectric loss, reflective loss, hardness, elastic modulus, bending strength, and fracture toughness are 13.89, 0.38, 49.40 dB, 6.4 ± 0.4 GPa, 262 GPa, 268.78 MPa, and 1.4 ± 0.1 MPa m1/2, respectively. Its ability to efficiently absorb microwave energy enhances the performance of devices including radar systems, communication equipment, and microwave heating systems, making it a promising candidate for microwave vacuum electronic applications.

The Transition from Face-to-Face Counseling to Videoconferencing Following the Onset of the COVID-19 Pandemic in Taiwan: The Client's Perspective

<p>COVID-19疫情嚴重威脅人們的身心健康，也加速通訊諮商的發展。原進行實體諮商的當事人，面對突發疫情須轉為視訊晤談，這轉換過程的經驗、對諮商關係的知覺，是本研究探究焦點。本研究以發現式研究取向，針對九位大學生當事人，透過半結構式深度訪談蒐集資料，並採紮根理論研究的資料分析方法。研究結果發現，當事人在轉換過程的經驗有四個主題，一是對視訊晤談的預想，正面期待與擔憂參半；二是視訊晤談過程實際困境，包含溝通品質不佳影響投入、虛擬空間療癒氛圍難以營造、情緒表達與覺察受限等，此一主題也是敘說最豐富的；三是有助持續視訊晤談的因素，包含當事人務實的考量、視訊困境的應對與調適；四是視訊晤談的正向經驗，包含省時便利、降低社交接觸的負擔。當事人對於轉換過程諮商關係的知覺有兩個主題，一是轉換對諮商關係的影響，包含情感連結的減損、諮商關係更親近；二是有助諮商關係維繫的因素，包含原有實體諮商基礎的加持、心理師即時的支持與回應。本研究認為在視訊晤談前準備度不足，是導致當事人衝擊經驗的主因之一，而當事人與心理師因應視訊形式的雙向調整有助於當事人調適視訊困境，此外，當事人在轉換過程普遍經歷情感連結的弱化，然原有實體諮商關係的基礎有助於調節轉換過程的不適。最後，依研究結果，提供相關實務與未來研究之建議。</p> <p> </p><p>The global COVID-19 pandemic was a serious threat to the physical and mental health of individuals. Due to social distancing measures, psychological counseling sessions that were previously held face-to-face had to be conducted through videoconferencing. In Taiwan, the two COVID-19 outbreaks in early 2020 and May 2021 necessitated the imposition of social restrictions. This study focuses on the experiences and views of college student clients who initially received counseling for mental health issues through face-to-face sessions but had to transition to online video counseling due to the epidemic.</p> <p>In this study, a qualitative research method with discovery orientation was adopted. The recruitment of study participants was carried out in two phases. The first phase targeted two universities in central Taiwan, while the second phase was expanded to include universities in northern and southern Taiwan. Both recruitments were promoted online on the school pages of several universities. Over 20 college students signed up in the two stages. After screening by the researchers through telephone and email, only 9 college students (female = 6), all sophomores or juniors, met the study criteria. Data collection was conducted through semi-structured, in-depth interviews conducted through videoconferencing due to social distancing constraints. Open coding, axial coding, and selective coding based on grounded theory research were used for data analysis.</p> <p>The analysis extracted four themes in the participants’ experiences of transition to videoconferencing. The first theme is the anticipation of the videoconference, which includes three sub-themes: feeling a sense of similarity to previous experiences of online social communication or distance learning, having positive expectations due to novelty and convenience, and worrying about the possible limitations of the videoconference or interfering distractions. The second theme addresses the challenges of videoconferences, encompassing three sub-themes: the adverse effects of poor dialogue quality on engagement, difficulties in establishing a comforting atmosphere in virtual spaces, and limitations on emotional expression and awareness. The participants discussed this theme frequently in the interviews. The third theme is related to the elements that enable the success of continuous videoconference interviews, including two sub-themes: pragmatic considerations of the client and coping with and adjusting to videoconferencing difficulties. Fourth, the positive experience of videoconferencing includes two sub-themes: time-saving and convenience, which reduce the burden of social contact. Two themes were identified in the participants’ perception of the counseling relationship during the transition process. One aspect to consider is the impact of transition on the counseling relationship, which includes two sub-themes: loss of emotional connection and a strengthened counseling relationship. The second theme pertains to the factors that contribute to maintaining the consultation relationship, encompassing two sub-themes: the support of an existing face-to-face counseling relationship and the immediate support and response from the counseling psychologist.</p> <p>This study suggests that the absence of proper informed consent by psychological counseling professionals before the videoconference is one of the main factors affecting the client’s experience. The quality of the videoconference session is significantly influenced by communication equipment and the environment. In addition, participants typically spoke of a weakening of the emotional connection in the counseling relationship during the transition process. The original face-to-face counseling relationship foundation helped to alleviate the discomfort of the transition process. Finally, based on the study results, recommendations for practice related to telecounseling and suggestions for future research directions are provided.</p> <p> </p>

Synthesis of Ti3C2Tx-MXene/PAN-derived double-loss Co/CeO2/TiO2/CNFs nanocomposites for enhanced microwave absorption performance

With the advancement of wireless communication and electronic equipment, microwave absorption materials (MAMs) have more and more broad applications in related fields. Ti3C2Tx-MXene with unique two-dimensional structure and excellent dielectric properties is often used as a precursor of nano-TiO2, which is a potential MAMs. Carbon nanofibers, as a one-dimensional material, have great electrical conductivity and can form interconnected three-dimensional conductive networks. In this study, Ti3C2Tx-MXene was prepared by in-situ HF etching method, and further combined with the benefits of Co, Ce metals, and carbon nanofibers. Co/CeO2/TiO2/CNFs were prepared via a facile technique for electromagnetic microwave (EM) absorption, exhibiting excellent EM absorption performance due to the synergistic effects of dielectric and magnetic properties. The minimum reflection loss (RLmin) and effective absorption bandwidth (EAB) reache −63.35 dB (11.2 GHz) and 3.6 GHz (9.5–13.1 GHz), with a thickness of only 2.35 mm and a filling rate of 30 wt%, while the maximum EAB reaches 5.4 GHz (12.4–17.8 GHz) with a thickness of 1.82 mm, covering nearly the entire Ku band. By offering a novel strategy to the creation of brand-new, high-performance MAMs based on 1D carbon nanofibers with dielectric/magnetic synergy, this work is believed to support the development of upcoming MAMs.

Statistical Measurement of Zhuhai's Digital Economy Development Level Based on Entropy Method

Against the backdrop of the increasing popularity of mobile internet and the expanding commercialization of fifth-generation mobile communications (5G), the digital economy is booming with continuous innovations and integrations of internet technologies such as artificial intelligence, blockchain, cloud computing, and big data. As one of the special economic zones, Zhuhai has emphasized in its work report the need to "vigorously develop the digital economy." Based on panel data from Zhuhai and its surrounding cities from 2018 to 2022, this paper empirically measures the level of digital economic development in Zhuhai and conducts a deep analysis of its development from the perspective of temporal characteristics. The research results indicate that: (1) Among various evaluation indicators of the digital economy, the output value of the communication and other electronic equipment manufacturing industries (in tens of thousands of yuan) has the greatest impact on the development of the digital economy, followed by the total volume of telecommunications business (in tens of thousands of yuan). The number of internet broadband users (in tens of thousands of households) and FTTH/O fiber-optic access users (in tens of thousands of households) have relatively smaller impacts. (2) In terms of temporal characteristics, the annual growth rate of Zhuhai's digital economy exhibits a steady decline, which differs from that of surrounding cities. (3) Regarding spatial characteristics, the development of the digital economy is highly unbalanced among different cities in Guangdong, and there is still a significant gap between Zhuhai and its surrounding cities. Based on the measurement results, countermeasures and suggestions are proposed to enhance the digital economic development in Zhuhai.

Computer Networking: Fundamentals, Models, and Security Considerations

Computer networking is an emerging and fascinating field of study. A computer network allows communication and exchange of information between two or more independent computers and other devices. Computer networking is based on the related discipline of electrical engineering, computer engineering, and computer science. Nodes and Links constitute the basic building blocks of the computer network. An equipment for data communication or equipment of data terminal that connects two or more computers such as modem, router etc. can be exemplified as a network node. Links include wires, cables or free spaces of wireless networks. Working of computer networks relies on a set of defined rules or protocols. The network structure can be composed of various patterns known as network topology. Various networking models are developed that relies on various networking layers made of different protocols. In modern times, the importance of computer networks is remarkable in almost every areas including education, entertainment, business, military, healthcare, insurance, transportation and others. With so much reliance on computer networking, it becomes important to ensure a safe and secure networking system and thus network security system was developed such includes firewall, VPNs, IDS and IPS, etc

Assessment of the characteristics of professional protective equipment, monitoring compliance with professional safety rules by nursing staff

Health system are more than three million working now, thousands of treatmentand- prophylactic, pharmaceutical, sanitary and epidemiologic institutions, tens research institutes, centers, highest and average educational institutions at which various household and communication equipment is operated, various medical equipment, are used toxic agents and aggressive liquids. In harmful and adverse working conditions hundreds of thousands workers of health care, including average health workers are occupied. Questions of professional safety of nursing staff on a workplace define a level of quality of labor life of experts and are the most important indicator of quality of the provided medical care. In this regard there is actual a question of means of professional protection of average health workers and observance of rules of professional safety by them.

High-frequency low-dielectric-loss in linear-backbone-structured polyimides with ester groups and ether bonds

Polyimides have emerged as promising dielectric materials for communication equipment, owing to their excellent thermal stability and processability. Nonetheless, a pressing need remains to reduce the high-frequency dissipation factor (Df) of polyimides. Here, we synthesized various polyimides featuring linear backbone structures, finding that polyimides that incorporate a combination of ester groups and ether bonds exhibit low Df values of 0.0015-0.0024 at 10 GHz. Even in high humidity and temperature conditions they maintain low Df values of <0.005 at 10 GHz. To gain insight into the factors influencing this behavior, we conduct a comprehensive study involving aggregation structures and hygroscopic properties. Our findings highlight the pivotal role of high orientation and crystallinity in determining the high-frequency Df of polyimide films.

REVIEW OF TRENDS IN APPLICATION OF VIRTUAL REALITY IN ENGINEERING

It is known that the growth rate of the mechanical engineering industry in the world is about 3% every year, and the growth leaders in the industry are motor vehicles, electronic components, communication equipment, computers and peripheral equipment, and aerial vehicles. The Industry 4.0 program is the next stage of the manufacturing enterprises digital transformation, the purpose of which is to increase the competitiveness of the Ukrainian economy machine-building sector. Industry 4.0 aims at the accelerated implementation of digital technologies, including the industrial Internet of Things, real-time big data analysis, artificial intelligence, the new generation of robots, virtual and augmented reality, etc. It is expected that the synergy of IT and production technologies will lead to the change in business models and a significant acceleration of innovative development at all stages from the development to the introduction into production of new products. On the basis of the National Technical University "Dniprovska Polytechnic", the direction of training students under the educational program "Technologies of virtual and augmented reality in mechanical engineering" specialty 133 Industrial mechanical engineering has been launched. The training of specialists with methodological and practical skills in the field of modern technologies of virtual and augmented reality is extremely important for the implementation of the Industry 4.0 strategy.

Foreign Trade of Ukraine’s ICT Sector: state and prospects

The article analyses the dynamics, features and structure of foreign trade of the ICT sector of Ukraine in 2008-2022, focusing on the exports and imports of ICT goods and services. It has been determined that the commodity structure of Ukraine’s ICT sector exports is dominated by communication equipment and consumer electronics, and that Ukraine mainly exported ICT goods to European countries, in particular to Hungary, Russia, Moldova, and Austria. At the same time, Ukraine imported the most communication equipment, as well as computer and peripheral equipment, mainly from China and Vietnam. The study of dynamics showed a long-term trend of decreasing exports and increasing imports of ICT goods by Ukraine. Additionally, the trade balance and indices of international trade in ICT goods showed a low level of specialization of Ukraine in the production and export of ICT goods. Having examined the structure of Ukraine's ICT services exports, we found that computer services predominate. The main importers of ICT services from Ukraine include the United States, the United Kingdom, Switzerland, Malta, and other countries. In addition, it has been determined that technology companies from countries that import ICT services from Ukraine have gradually opened their own R&amp;D centres in Ukraine. The study of the dynamics of foreign trade in ICT services during 2008-2022 showed a constant upward trend in the volume and share of ICT services in Ukraine's exports of services. In addition, the calculation of the trade balance and international trade indices for 2008-2022 showed a high level of specialization and competitiveness of ICT services in the Ukrainian economy. The article identifies the main factors and reasons that influenced the trends in foreign trade of the ICT sector of Ukraine. Finally, three possible scenarios for the development of Ukraine's ICT sector over the next few years were outlined.

Lower Atmospheric Ducts over the South China Sea Related to the Monsoon, Atmospheric, and Ocean Conditions Based on ECMWF Reanalysis Data

Abstract Atmospheric ducting is a highly refractive propagation condition that frequently occurs at sea and significantly impacts radar and communication equipment. This paper analyzes the spatiotemporal distribution of lower atmospheric ducts (LAD) in the South China Sea (SCS) and the variation of their occurrence rate with the monsoon by using reanalysis data from the ECMWF from 1980 to 2022. Additionally, the study discusses the relationship between ducting occurrences and atmospheric and oceanic conditions. The results indicate that wind dynamics in the SCS significantly impact ducting incidents. During the high-incidence period of LAD, humidity-gradient-constructed ducts are the primary mechanism. Before the onset of the monsoon, the mountains in the western part of Luzon Island obstruct the easterly wind, resulting in high temperatures and strong evaporation along the western coast of the mountains. Meanwhile, low temperatures and humidity prevail in the eastern part of the mountains, and they lead to a stratified atmosphere characterized by dry and cold upper layers and warm and humid lower layers in the western part of Luzon Island, which causes a distinct decrease in humidity with height. After the onset of the monsoon, the air from the Indochina Peninsula to the ocean is dry and cold, but the high-altitude area blocks it. This weakens the horizontal mobility of the low-level humid atmosphere over the sea, resulting in atmospheric stratification in the eastern coastal area of the Indochina Peninsula. This stratification leads to dry and cold upper layers and warm and humid lower layers. Significance Statement Atmospheric ducting is a superrefractive propagation condition that frequently occurs at sea and has a significant impact on radar and communication equipment and is related to large-scale or medium- and small-scale atmospheric stratification. The distribution of land and sea around the South China Sea (SCS) and the monsoon are important factors affecting the existence of atmospheric ducts in this region. Many scholars have studied the mechanism of atmospheric ducts in local areas based on observation data (or reanalysis data). The literature on the atmospheric ducts in the SCS mainly focuses on the spatial and temporal statistical distribution of seasons, months, and days, and gives the spatial and temporal distribution characteristics of the region within the statistical time, emphasizing the important influence of the monsoon on the duct, but there is no relevant research on the reasons for the existence of the specific relationship and its temporal and spatial distribution characteristics. The manuscript analyzes the temporal and spatial distribution of lower atmospheric ducts in the SCS and the variation of their occurrence rate with the monsoon, quantifies the contributions of temperature, humidity, and air pressure to the ducting occurrence, meanwhile discussing the ducting occurrence relation with atmospheric and oceanic conditions. In the end, we demonstrate that the development of high-incidence areas for SCS ducts prior to and following the onset of monsoon season is connected to factors such as wind patterns, seawater evaporation, and topography. Furthermore, unstable vertical transport of water vapor in both the atmosphere and oceanic conditions plays a crucial role in facilitating the creation of humidity-type ducts.

Optimal operation of multiple energy system considering load management approach and uncertainty

In recent years, the advancement of technology has led to the development of energy networks' infrastructure, resulting in the transformation of conventional networks into smart networks. By incorporating communication equipment, each component of the network can now exchange information with other components, creating an environment where innovative ideas can be implemented. One such idea is the utilization of multi-carrier energy systems, also known as Energy Hubs. Integrating energy hubs into traditional networks used to be a challenging task. However, with the expansion and enhancement of smart networks, the potential for incorporating and locating energy hubs within the power grid has significantly increased. In these systems, the focus shifts from optimizing a single energy carrier to ensuring the optimal operation of a system that encompasses multiple energy carriers, such as natural gas, electric grid, and thermal energy. Energy hubs act as intermediaries between energy supply companies and various consumers, including residential, commercial, and industrial sectors. These energy suppliers can encompass different energy networks, such as electricity, gas, and local heating. The integration of residential and commercial energy hubs has become a crucial aspect of modern energy systems, particularly in the context of load response applications. This paper proposes a novel approach for effectively utilizing residential and commercial energy hubs, taking into account the time of use (ToU) load response program. In the proposed system, the inherent uncertainties of the system are addressed using the two-point estimation method of the model. To achieve the desired objective, the Cuckoo optimization algorithm, a well-established meta-heuristic algorithm for solving optimization problems, is employed. This algorithm aids in determining the optimal scheduling of energy resources while considering ToU tariffs and load management plan signals. The results demonstrate that the proposed approach can significantly reduce energy costs for the energy system.

Study of Sky Radio Frequency Interference Background Level Behavior During the Partial Solar Eclips on 25 Oct. 2022 at The Baghdad University Location

Radiofrequency interference (RFI) describes the weakening of radio astronomy transmissions caused by man-made radio signal noise in radio telescope observation indicates the level of radio frequency noise in the sky at all times, regardless of any astronomical sources. This noise is affected by various sources, including Earth's atmosphere or solar activity and all communications equipment operating near the radio telescope. In this study, the background noise which includes RFI was measured using HSA2000 series receiver spectrum analyzer, which connected with two dipole antennas in different frequency bands (15-80 MHz) low band antenna, and (110-240 MHz) high band antenna during the partial solar eclipse in Baghdad on October 25, 2022, at (12:00-15:00), as a simple radio telescope to observe the radio astronomical background level in the sky. It is clear that the average amount of RFI level during a partial solar eclipse (-83.249 dBm for LBA decreased by about (0.93) from the value on a normal day (-77.495 dBm). And For HBA -84.711 dBm decreased by about (0.85) from the value on a normal day (-72.784 dBm). Also, it was noticed that these amounts are approximately equal to the RFI level at night (-82.352 dBm for LBA and -82.739 dBm for HBA). It is (0.98) for LBA and (0.97) for HBA, respectively. This research confirms that despite the short duration of the partial eclipse, the average value during the partial eclipse period is close to the average values during the night period due to the decrease in the electronic density of the ionosphere, especially at low frequencies, and the FRI of ground disturbances as a result of the activities of human from the surrounding the monitoring area. also, found that at the monitoring point, there is a good relationship between the time of the maximum partial eclipse and the peaks of signal gain strength.

Network Performance and Technological Feasibility of Unmanned Aerial Vehicles for Network Extension

The operational range of conventional and license-free radio-controlled drones is limited due to line-of-sight restrictions (LoS). There exists a definitive method for operating a drone. Consequently, in order to fly the drone beyond the visual line of sight (BVLoS), it is necessary to replace the drone's original wireless communications equipment with a device that requires a licence and is connected to a cellular network. Long-Term Evolution (LTE), a terrestrial communication technique, enables a drone to establish a real-time connection with a ground station. This connection serves the goals of command and control (C&amp;C) as well as payload delivery. Nevertheless, it is important to note that the electromagnetic environment undergoes changes as altitude increases, which can potentially complicate the process of interfacing with drones over terrestrial cellular networks. The objective of this article is to develop a prototype control system for low-altitude microdrones using LTE technology. Additionally, it seeks to assess the feasibility and effectiveness of cellular connectivity for drones operating at various altitudes. This evaluation will be conducted by examining factors like as latency, handover, and signal strength. At a certain altitude, the received signal experiences a decrease in power level by 20 dBm and a degradation in signal quality by 10 dB. The data throughput of the downlink had a fall of 70%, while the latency exhibited an increase of 94 ms. Despite meeting the basic criteria for drone cellular connection, the existing LTE network necessitates enhancements in order to expand aerial coverage, mitigate interference, and minimise network latency.

An Integrated Duranton and Overman Index and Local Duranton and Overman Index Framework for Industrial Spatial Agglomeration Pattern Analysis

Accurately measuring industrial spatial agglomeration patterns is crucial for promoting regional economic development. However, few studies have considered both agglomeration degrees and cluster locations of industries. Moreover, the traditional multi-scale cluster location mining (MCLM) method still has limitations in terms of accuracy, parameter setting, calculation efficiency, etc. This study proposes a new framework for analyzing industrial spatial agglomeration patterns, which uses the Duranton and Overman (DO) index for estimating agglomeration degrees and a newly developed local DO (LDO) index for mining cluster locations. The MCLM-LDO method was proposed by incorporating the LDO index into the MCLM method, and it was validated via comparisons with three baseline methods based on two synthetic datasets. The results proved that the MCLM-LDO method can achieve accuracies of 0.945 and 1 with computational times of 0.15 s and 0.11 s on two datasets, which are superior to existing MCLM methods. The proposed framework was further applied to analyze the spatial agglomeration patterns of the industry of computer, communication, and other electronic equipment manufacturing in Guangdong Province, China. The results showed that the framework gives a more holistic perspective of spatial agglomeration patterns, which can serve as more meaningful references for industrial sustainable development.

Функциональная модель объединенного источника комплексной системы синхронизации и доставки шкалы времени для крупной и распределенной системы технологического назначения

Purpose: to develop scientific and technical proposals and requirements for building sources of synchrosignals and messages of a single time for the integrated system of synchronization and delivery of the time scale depending on the requirements in frequency-time support signals and the current communication chain architecture in the framework of solving a unified synchronization system in phase time and the frequency in large territorially distributed and industrial technological systems. Methods: the applied research methods include the fundamental provisions of the theory of constructing synchronization systems, as well as infocommunication systems and networks. Results: a functional model of a united source of the integrated system of synchronization and delivery of the time scale, which includes a complete set of elements to perform the functions of synchronization and delivery of single-time signals in existing and promising complex heterogeneous networks with various architecture and heterogeneous equipment that differs from the existing fully taking into account the existing ones in Currently, technologies for delivery of single time and frequency signals, both on the basis of switching packages and on the basis of switching of channels. The proposed functional model of the united source of the integrated system of synchronization and delivery of the time scale will allow to reasonably approach the design of the means of transmitting and delivering single time and frequency signals to various and heterogeneous communication networks, taking into account all the needs for frequency-time support signals and limiting existing communication networks. Practical significance: the use of sources of single-time and frequency signals, which are based on the proposed functional model, will ensure a flexible infrastructure to ensure the unity of the unity of the unified time and clock network synchronization necessary for the correct functioning of communication equipment; Satisfy the requirements of synchronization signals and uniform messages for promising and existing consumers as much as possible; ensure the possibility of a phased transition of the construction of communication networks from the technologies of the channels to the technology of switching packages due to flexibility in the use of routes and transmission systems necessary for the spread of synchrosignals and uniform messages.