This paper presents a compact broadband circularly polarized (CP) filtering patch antenna with multi-element coupling structure. The antenna consists of two substrate layers. The upper substrate layer incorporates a main radiating patch with an etched rectangular slot, a pair of unequal-sized L-shaped parasitic stubs placed along the + 45° diagonal of the main patch, and surrounding microstrip patches. The lower substrate features a ground plane etched with an asymmetric U-shaped slot on its top surface and a microstrip feedline on the bottom. The signal enters the port, propagates along the microstrip feedline, and couples to the main radiating patch through the asymmetric U-shaped slot, generating CP radiation. Further coupling between the main patch and the surrounding microstrip patches produces two additional CP modes, enabling wideband CP operation. Without the need for additional filtering circuits, the antenna achieves bandpass filtering characteristics by introducing two controllable radiation nulls near 2.0 GHz and its second harmonic at 4.0 GHz through the unequal L-shaped parasitic stubs. A third radiation null near 3.6 GHz is generated by the rectangular slot etched on the main patch. The proposed design maintains a compact profile (<inline-formula> <tex-math notation="LaTeX">$0.54 \lambda_0 \times 0.54 \lambda_0 \times 0.07 \lambda_0$ </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> corresponds to the lowest operating frequency) while realizing integrated wideband CP and filtering performance. The measured results demonstrate an impedance bandwidth of 23.1% (2.64–3.33 GHz), an axial ratio (AR) bandwidth of 11% (2.8–3.125 GHz) and a stable in-band gain of approximately 7 dB. The out-of-band suppression levels reach 17 dB and 24 dB in the lower and upper stopbands, respectively, confirming good CP filtering performance.
Ahatesham Bhuiyan, Eftekhar Hossain, Mohammed Moshiul Hoque
et al.
Image captioning, the process of generating natural language descriptions based on image content, has garnered attention in AI research for its implications in scene understanding and human-computer interaction. While much prior research has focused on caption generation for English, addressing low-resource languages like Bengali presents challenges, particularly in producing coherent captions linking visual objects with corresponding words. This paper proposes a context-aware attention mechanism over semantic attention to accurately diagnose objects for image captioning in Bengali. The proposed architecture consists of an encoder and a decoder block. We chose ResNet-50 over the other pre-trained models for encoding the image features due to its ability to solve the vanishing gradient problem and recognize complex object features. For decoding generated captions, a bidirectional Gated Recurrent Unit (GRU) architecture combined with an attention mechanism captures contextual dependencies in both directions, resulting in more accurate captions. The paper also highlights the challenge of transferring knowledge between domains, especially with culturally specific images. Evaluation of three Bengali benchmark datasets, namely BAN-Cap, BanglaLekhaImageCaption, and Bornon, demonstrates significant performance improvement in METEOR score over existing methods by approximately 30%, 18%, and 45%, respectively. The proposed context-aware, attention-based image captioning system significantly outperforms current state-of-the-art models in Bengali caption generation despite limitations in reference captions on certain datasets.
This paper outlines the specific provisions of Italian legislation regarding workers’ exposure to electromagnetic fields (EMFs) from 0 Hz to 300 GHz compared to the minimum health and safety requirements set in European Directive 2013/35/EU. In particular, the path to be followed to assess and manage occupational exposure to EMFs is outlined in relation to the distinction between ‘professional’ and ‘non-professional’ exposure of workers, as well as to the precautionary limits regarding exposures from power lines (50 Hz) and broadcast and telecommunication fixed systems (100 kHz–300 GHz) established by Italian regulations. The reasons underlying such an approach—mainly relying on the intent to reconcile scientific evidence with risk perception in public opinion—are analysed and discussed with the aim of increasing the knowledge of national regulatory provisions on occupational risk assessment, which may be more stringent than the requirements envisaged by international guidelines and community regulations.
Industrial safety. Industrial accident prevention, Medicine (General)
This article performs a detailed data scrutiny on a chronic kidney disease (CKD) dataset to select efficient instances and relevant features. Data relevancy is investigated using feature extraction, hybrid outlier detection, and handling of missing values. Data instances that do not influence the target are removed using data envelopment analysis to enable reduction of rows. Column reduction is achieved by ranking the attributes through feature selection methodologies, namely, extra-trees classifier, recursive feature elimination, chi-squared test, analysis of variance, and mutual information. These methodologies are ranked via Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) using weight optimization to identify the optimal features for model building from the CKD dataset to facilitate better prediction while diagnosing the severity of the disease. An efficient hybrid ensemble and novel similarity-based classifiers are built using the pruned dataset, and the results are thereafter compared with random forest, AdaBoost, naive Bayes, k-nearest neighbors, and support vector machines. The hybrid ensemble classifier yields a better prediction accuracy of 98.31% for the features selected by extra tree classifier (ETC), which is ranked as the best by TOPSIS.
The communication network based on quantum key distribution (QKD) has the ability to realize “perfect secrecy”.At present, it cannot meet the needs of large-scale applications and needs to combine classical cryptography in practical applications.Firstly, the functional architecture model of the telecom-operators cryptography application system integrating quantum key distribution was proposed, and then the hierarchy, the core network elements, the functional modules, and the interface relationships of the model were described.Furthermore, the framework of the application system was given, and the main components of the framework were introduced.Finally, the typical application scenarios and workflow were illustrated.
Robert Mroczyński, Grzegorz Głuszko, Romuald B. Beck
et al.
This work reports on changes in the properties of ultra-thin PECVD silicon oxynitride layers after high- temperature treatment. Possible changes in the structure, composition and electrophysical properties were investigated by means of spectroscopic ellipsometry, XPS, SIMS and electrical characterization methods (C-V, I-V and charge- pumping). The XPS measurements show that SiOxNy is the dominant phase in the ultra-thin layer and high-temperature annealing results in further increase of the oxynitride phase up to 70% of the whole layer. Despite comparable thickness, SIMS measurement indicates a densification of the annealed layer, because sputtering time is increased. It suggests complex changes of physical and chemical properties of the investigated layers taking place during high-temperature annealing. The C-V curves of annealed layers exhibit less frequency dispersion, their leakage and charge-pumping currents are lower when compared to those of as-deposited layers, proving improvement in the gate structure trapping properties due to the annealing process.
Disseminating information through the World Wide Web as the most popular medium has resulted in creating a huge number of web pages and so growing the dimension of the web. In this era of big data, an efficient website ranking to satisfy the web user requirements in different areas such as marketing and E-commerce is a major challenge in the current Internet. In this context, the role of ranking algorithms as a tool to provide services such as measuring the website visibility and comparing the website position to the competitors is crucial. In this paper, we propose an architecture for web domain ranking which includes processing capability required for handling Big Data available on the web. The proposed architecture presents a new method for web domain ranking that is independent of the link structure of the web graph. The proposed method provides web domain ranking based on the number of unique visitors, the number of user sessions, and session duration.
The traveling-wave tube is a critical subsystem for satellite data transmission. Its role in the history of wireless communications and in the space conquest is significant, but largely ignored, even though the device remains widely used nowadays. This paper presents, albeit non-exhaustively, circumstances and contexts that led to its invention, and its part in the worldwide (in particular in Europe) expansion of TV broadcasting via microwave radio relays and satellites. We also discuss its actual contribution to space applications and its conception. The originality of this paper comes from the wide period covered (from first slow-wave structures in 1889 to present space projects) and from connection points made between this device and commercial exploitations. The appendix deals with an intuitive pedagogical description of the wave–particle interaction.
Karunesh Srivastava, Sweta Singh, Aditya Kumar Singh
et al.
A wideband antenna with dual band characteristic at 5.33/14.3GHz with resonating frequencies for wireless applications is presented. The strategy of the design is to introduce multiband in antenna band. Bandwidth of the antenna increases by embedding annular ring on the radiating patch and four bands are achieved by introducing coupling gap between the patches. Surface current distribution is analyzed at different resonating frequencies for understanding the radiation mechanism and effect of annular ring. The antenna parameters such as return loss, radiation pattern, gain, VSWR and group delay are discussed. The impedance bandwidth of the proposed dual band antenna at lower resonant frequency is 12.7% (simulated) and 9.8 % (measured) whereas at upper resonant frequency is 15.3 % (simulated) and 13.97 % (measured).
This paper provides a study of the smart grid projects realised in Europe and presents their technological solutions with a focus on smart metering Low Voltage (LV) applications. Special attention is given to the telecommunications technologies used. For this purpose, we present the telecommunication technologies chosen by several European utilities for the accomplishment of their smart meter national roll-outs. Further on, a study is performed based on the European Smart Grid Projects, highlighting their technological options. The range of the projects analysed covers the ones including smart metering implementation as well as those in which smart metering applications play a significant role in the overall project success. The survey reveals that various topics are directly or indirectly linked to smart metering applications, like smart home/building, energy management, grid monitoring and integration of Renewable Energy Sources (RES). Therefore, the technological options that lie behind such projects are pointed out. For reasons of completeness, we also present the main characteristics of the telecommunication technologies that are found to be used in practice for the LV grid.