International Journal of Wireless and Microwave Technologies @ijwmt
Journal articles - International Journal of Wireless and Microwave Technologies
All articles: 622
Structure and Control of Flywheel Energy Converter
Scientific article
On the basis of the flywheel energy converter’s structure in wind power turbine, we have used permanent-magnet synchronism motor as energy converter and built mathematical model. We have studied and realized control method of wind power turbine’s constant output power. By analyzing the mathematical model, we have concluded that the needed time of stored energy is three times longer than constant torque control time, and the needed motor power is one second of constant torque control. When flywheel starts from zero speed to basic speed ([(ω_max)/5]), the constant torque control method will be acquired. When flywheel speeds up between [(ω_max)/5] and ω_max , the amplitude power control will be acquired. What we have studied is very important to realize constant output power.
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Study of 2457 MHz WIFI Network Signal Strength at Indoor and Outdoor Enviroment
Scientific article
This paper presents a study of free space path loss of WIFI network using Cell Info Lite App and WIFI analyzer tool. This paper focuses on experimental tests by using WIFI router, mobile phones to measure and analyze the loss of signal strength over distance from 0 meter to 9 meter. The result of Free Space Path Loss (FSPL) for frequency 2457 MHz shows that the longer the distance, the worse the signal get. In addition, the experiment test indoor and outdoor was done analyse. The results of the comparison conclude that the signal strength becomes weak can affect by distance and obstacles such as door, wall. Signal strength also can say from colors which is when the measurement result shows green color is strong signal while orange color is weak signal and red color is bad signal. When the signal strength become weak Wi-Fi analyzer was displayed green zone to red zone. The paper purpose showed that where the area have a stronger/weaker connection in a house environment.
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Study on Quality Evaluation System for University Students
Scientific article
From the qualitative and quantitative perspectives, by use of modern educational philosophy and statistics evaluation theory, this thesis makes study on the theory for university students’ comprehensive quality evaluation. It makes careful analysis on the students’ daily life according to their characters, and makes scientific classification after picking up the main aspects, and then, combining the design principle of indictor system and hierarchic method, it establishes scientific and reasonable comprehensive quality evaluation indicator system for university students, which is easy to operate and meets the demand of the age. So the system can measure and evaluate the comprehensive quality of university students in a more scientific and objective way. Meanwhile, this thesis puts forward effective methods for university students’ comprehensive quality evaluation under new situations.
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Study on Replica Strategy in the Grid Environment
Scientific article
An effective replica management method can save bandwidth, reduce latency, balance load, and improve system reliability. A comprehensive scheme is introduced to manage replica for the grid environment. The schemes of replica creation and placement based on the frequency of visits and storage space, replica replacement based on the replica value, and replica selection based on comprehensive performance are proposed. Our scheme can achieve optimization of data distribution and replication, improve the efficiency of data visits in the grid environment.
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Study on System Architecture Design of University Students Quality Evaluation
Scientific article
In order to improve the comprehensive qualities of students in all respects, fully reflect and evaluate the achievements of students, inspire students to improve themselves unceasingly, encourage them to strive to be the best, develop their personalities and strive for truth and innovation, as well as achieve the institutionalization, standardization and scientificalness of students management work gradually, meanwhile, along with the development of university construction and students management, maintenance and management of students' data information has been exceptionally heavy, so it cries out for a set of reasonable and convenient students quality evaluation system. Students' quality evaluation system is designed to make better use of computer technology in managing and inquiring about total performance of students' qualities. Through analysis of the objective of system construction, combining design principle of the system, this thesis analyses and designs the quality evaluation system architecture from the perspectives of architecture, function module and security model.
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Study on Thickness Calculation Method for Undigraph
Scientific article
How to solve the thickness of general graph is an unsolved problem and one of many difficult problems in graph theory. This paper studies the method for calculating the thickness of undigraph and proposes formula and concrete method for calculating the thickness of undigraph G. Meanwhile, method is proposed for testing whether division of side-derived subgraphs is correct. Some instances presented in this paper aims at illustrating the actual application and correctness of calculation of this method for reference.
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Study on the Distribution of Networked Devices’ Clock Skew
Scientific article
Clock skews of devices on the Internet are viewed as one way delay noise, but their distribution is unknown. We explore the distribution of clock skews to see the conflict probability. In this paper, we introduce an accurate clock skew estimation algorithm to filter inaccurate clock skew estimation by comparing the results between linear programming method and least square fitting. Delay jitter and other noises affect the estimation result. When the difference of two methods is large, the estimation result is unstable and inaccurate, so the estimation result should be dropped. Based on this algorithm, we use traces of real Internet measurements to collect 1825 accurate clock skews of different devices to establish a fingerprint database. Furthermore, we show the distribution of clock skews and comparing conflict probability with different number of devices. The distribution shows that clock skews are diverse, and most of clock skews are in the region of [-100, 100] PPM. The results indicate that when the number of devices is small (<5), clock skews won’t be conflict with each other, so clock skews are good tools to detect faked devices or NAT; When the number of devices increases, the conflict probability increases linearly, so clock skews of different devices can not distinguish each devices effectively.
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Supporting Audio Privacy-aware Services in Emerging IoT Environment
Scientific article
The increasing exploration of smart space voice assistants and audio monitoring IoT devices leads to significant trust and privacy concerns. Among them, some of the data are sensitive and a user may not aware of when and where audio recordings are sent for processing. This provides burning questions- how do users gain knowledge of, and control the amount of data captured in the physical world. Moreover, the sending and processing of these sensitive data to the far cloud do not provide an efficient solution for sensitive data which causes serious privacy and security concerns. In this paper, a new architecture for providing audio transparency and privacy in the IoT-rich environment is proposed. The proposed privacy enforcement module is used to operate within a nearby fog node, which situated close to the data sources and enforces privacy according to the data owner's desire. To show the effectiveness of the proposed architecture, a well-known privacy threat framework is investigated.
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Surface Fitting Based Modelling of a Circular Microstrip Patch Antenna Operating at 3 GHz Frequency
Scientific article
Designing a microstrip patch antenna at 3GHz frequency is very interesting task to the researchers due to wide applicability for IoT, body wearable antenna, WLAN, ISM communication etc. In this paper, a circular microstrip patch antenna with resonance at a frequency of 3GHz has been designed using FR4 substrate and inset feeding using CST studio. Initially, the antenna is manually tuned at the 3GHz operating frequency and obtain S11 is -38dB which is best compare to the existing works at this frequency. Next, the parametric influences have been observed by varying several antenna design parameters (i.e. patch radius and substrate height) and observing the respective variation in output like S11, bandwidth. In the next phase of this work, surface fitting technique has been used to model the 3GHz circular patch antenna that helps to predict the output S11, resonance frequency and bandwidth with satisfactory prediction accuracy. Surface-fitting model will help to reduce the effort and time required for redesigning and simulation of this type of circular patch antenna in future.
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Survey on 5G and Future 6G Access Networks for IoT Applications
Scientific article
This paper comprehensively reviews the recent 5G and future 6G Internet of Things (IoT) protocols/standards, applications, and access networks used. First, most of the IoT protocols/standards and application scenarios are summarized in the form of tables, pictures, and diagrams to facilitate readers to understand and compare current and future Internet of Things technologies more easily and quickly. Second, the terrestrial and aerial radio access networks are analyzed and discussed in detail. The evolution of 5G terrestrial access networks is briefly described and its performance limitations are quantitatively analyzed and discussed. When the operating frequency reaches the sub-millimeter wave band, the terrestrial radio access network will deal with high path loss caused by weather factors, such as oxygen and water vapor absorption in the atmosphere, rainfall, and cloud/fog attenuation. The development of aerial radio access networks is preparing for 6G IoT to solve the coverage and path loss issues. In this survey, the aerial radio access architectures and infrastructure are also surveyed. This survey aims to guide readers to better understand the technical status of 5G IoT and the milestones as well as key performance indicators that need to be reached for 6G IoT in the future.
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TCP/IP Jumbo Frames Network Performance Evaluation on A Test-bed Infrastructure
Scientific article
Enhancing network performance has been studied by a number of researchers. The need to provide greater throughput on network infrastructure has been the key driver for these studies. The use of jumbo frames is considered one of the methodologies that can be employed to increase data throughput on networks. In this research undertaking, the authors implement jumbo frames on a test-bed implemented with Windows Server 2003/2008 networks and performance related metrics are measured for both IPv4 and IPv6 implementations. The results obtained in this empirical study shows that performance metrics values are different in various scenarios.
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The Application of Federated Kalman Filtering in SINS/GPS/CNS Intergrated Navigation System
Scientific article
Federated filter was an important method to estimate high-precision navigation parameters based on “SINS/GPS/CNS”. A no-feedback federated filter with UD_UKF algorithm was designed in the paper, a three-time amendment scheme to correct navigation parameters was designed at the same time and the mathematical model of SINS/GPS/CNS was established in launch inertial coordinate system too. The paper discussed the simulation conditions and a lot of simulations were carried out to compare 2 aspects: (1)the performance between four navigation mode, which respectively is SINS, SINS/GPS, SINS/CNS, SINS/GPS/CNS;(2)the estimate precision of federated filter and that of centralized Kalman filter. The results of simulation showed that the designed federated filter and amendment scheme based on SINS/GPS/CNS had high estimate precision and led to gain high hitting precision of ballistic missile, that is to say position errors were less than 20 meter and velocity errors were less than 0.1m/s in simulation.
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The Channels and Demands Analysis for Chinese Farmers’ Agricultural Information Acquisition
Scientific article
This paper studies the characteristics of information sources and farmers’ demand for agricultural information in the process of agricultural informationization in China. We point out that it is not common for farmers to adopt modern information technology communication tools in rural areas nowadays, and the reason for this phenomenon is that farmers still rely mainly on traditional channels for information dissemination. To change the status quo, our government should respect farmers as dominant statuses in the process of agricultural informationization and encourage households with large-scale agricultural operation to use modern IT products in order to spread agricultural information in rural areas.
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Scientific article
Unregulated accessibility to the latest deepfake technologies presents escalating, unprecedented threats to the personal security, public trust, and democratic integrity, owing to the ever-increasing sophistication and realism of these forgeries. The biggest challenge is the inability of human verification to ascertain the original from the forgeries. Therefore, this research aims to establish an initial framework of detection and verification. The Chromatic Gradient Anomaly Network (ChrGAN) is an architecture that will be built and tested to capture changes of the various components of a video over time in order to reveal patterns of inconsistency between the spatiotemporal levels of a video and the changes of its chromatic components. One of the most important contributions of this research is the analysis of the second order derivatives (in this case, the Chromatic Gradient Fields) of the Spatiotemporal Chromatic Energy Distributions, leaving the synthesis boundary of the temporally sparse flickers and the physically implausible discontinuities of the blend exemplified by the gap. The results for the CrGAN show the highest level of diagnostic confidence, reporting a detection rate of 97.9%, and most importantly a level of pixel-wise localized mapping of the region detected that is statistically differentiated from the other detection models for a state of the art performance measurement in a machine learning model for the detection only. In conclusion, this study validates how targeting the second-order spatiotemporal inconsistencies using chromatic gradients, not only acts as an efficient detection mechanism, but also as an interpretable tool in the combat against digital deception by identifying the how and where of video forgery.
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The Comparison of Machine Learning Algorithms on Online Classification of Network Flows
Scientific article
Online classification of network flows is a process that captures packets generated by network applications and identifies types of network applications (or flows) in real time. There are three key issues about online classification: observation window size, feature selection, and classification algorithms. In this paper, by collecting five types of typical network flow data as the experiment sample data, the authors found observation window size 7 is the best for the sample data and most classifiers. The authors proposed a full feature set based on the standard feature set which reflects statistical features of network flows. Using five commonly used feature selection methods, the authors identified the most effective features could be reduced from 56 original features to 11 effective features. Lastly, according to special need for online classification, the authors studied 11 different classifiers on their classification accuracy, model construction time, and classification speed. The results show that C4.5 and JRip are the two best algorithms for online classification.
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Scientific article
The accelerating pace of digital transformation has expanded dependency on online services, exposing a widening misalignment between technology adoption and cybersecurity competence. This study investigates generational disparities in digital security literacy, perceived risk, and protective behaviors, with a particular focus on senior citizens as high-risk end users within computer network and information security ecosystems. 112 participants from various age and professional cohorts were surveyed using a four-point Likert scale with minimal central tendency response bias followed by both descriptive and mean-comparison analyses. Results demonstrate that cybersecurity literacy is medium but uneven (mean = 2.02), with respondents from the oldest age group (age sixty and above) reporting the lowest composite security score and weakest preventive practices, including a Two-Factor Authentication penetration of only 35%. There is a clear confidence-competence gap (+0.47) among senior citizens, meaning they tend to overestimate their ability to deal with digital services but underestimate the challenge of acquiring technical knowledge. Building on these findings, the paper introduces the Digital Guardian for Seniors framework a conceptual, human-centric intervention model integrating adaptive, visually oriented pedagogy, an intergenerational cyber-buddy system, and suggested metrics for longitudinal evaluation. The study contributes to computer network and information security research by providing demographic-based empirical evidence and outlining a theoretical foundation for future empirical testing and targeted interventions for an aging digital population.
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The Economic Evaluation of Lighting Energy-saving Modification Program
Scientific article
Many lighting energy-saving modification programs have the embarrassment of uneconomical. This paper takes into account economic evaluation to solve the problem. According to illuminative equipments price, life span and power consumption, the optimal program will be found under the limited investment. Firstly, the benefit ratio will be used to evaluate on the equipments modification necessity, and get the modification sequence. If the biggest benefit ratio is in different equipment simultaneously, the better one will be selected in terms of relative investment recovery period. The relative remaining time is innovatively introduced into economic evaluation for determining the equipments modification locations. Then the system operation flowchart is to prove that the scheme is workable.
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The Empirical Study on the Relationship between Knowledge Integration and IT Project Performance
Scientific article
This article examines the relationship between timely project completion and the management’s integrative capability. Measures of the integrative capability are used to predict on-time project completion, where completion is a function of the duration of IT-related project delays. In a longitudinal study of 74 enterprise application integration projects in the medical sector, integrative capability was measured from the point of view of the CIO and a facility IT manager. Accounting for several project controls, our Cox regression results indicate both integrative dimensions significantly mitigate the duration of IT-related project delays, thus promoting timely project completion. The analysis also reveals the importance of taking management structure into consideration when studying IT phenomena in networked organizations.
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The Existence of Homoclinic Solutions for Second Order Hamiltonian System
Scientific article
The research of homoclinic orbits for Hamiltonian system is a classical problem, it has valuable applications in celestial mechanics, plasma physis, and biological engineering. For example, homoclinic orbits rupture can yield chaos lead to more complex dynamics behaviour. This paper studies the existence of homoclinic solutions for a class of second order Hamiltonian system, we will prove this system exists at least one nontrivial homoclinic solution.
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The Impact of Artificial Intelligence on Cybersecurity and Data Protection
Scientific article
The escalating complexity of cybersecurity threats necessitates advanced technological solutions to protect digital infrastructures. This study explores the application of Autoencoder neural networks, a deep learning model, for anomaly detection in network traffic, aiming to enhance real-time identification of cyberattacks. Using the CICIDS2017 dataset, which encompasses diverse attack types such as Distributed Denial of Service (DDoS) and infiltration, the Autoencoder was trained to detect deviations from normal traffic patterns based on reconstruction errors. The model was optimized through preprocessing, feature selection, and hyperparameter tuning, achieving strong performance metrics including precision, recall, F1-score, accuracy, and ROC-AUC. Despite its effectiveness in distinguishing normal and malicious traffic, challenges arose in detecting stealthy attacks like slow brute-force attempts. These results underscore the Autoencoder's potential in cybersecurity frameworks and highlight opportunities for improvement through adaptive thresholds and hybrid models. This study contributes to advancing AI-driven anomaly detection, promoting proactive defense against evolving cyber threats.
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