When the limit miniaturization of the coupler is achieved when the elements are located in one conductive layer, then miniaturization can be continued by changing the design of the capacitor that is part of the filter: reducing the gap between the plates or increasing the dielectric constant between the capacitor plates, and due to the movable plates, you can change the operating frequency of the coupler.

Securely and reliably connecting multiple operating sites using existing Internet access lines is a common requirement for companies as well as individuals. Towalink is a new open and flexible solution for interconnecting multiple network sites reliably and securely. It is built around proven open-source projects and by itself published open-source. We present in theory and based on a practical setup the central management it provides and show how it is following the infrastructure-as-code paradigm.

In this paper presents the design and radiation characteristics of a stepped printed dipole antenna array element. The array element is designed to operate in the 5G millimeter wavelength (mm-Wave) range (from 24.25 to 27.50 GHz). In the required frequency band, the value of the VSWR does not exceed 1.30. The value of the realized gain ranges from 4.53 to 5.59 dB. The overall dimensions (width × depth × height) are 6 mm × 6 mm × 2 mm. Based on it, a model of a 4 ×4 antenna array was developed. Its radiation characteristics were compared with the characteristics of the arrays of the differently shaped dipole antennas (a horizontal flat, a horizontal flat with matching inserts, a vertical flat, and a volumetric). It is shown that the stepped shape of the dipole makes it possible to obtain the best characteristics.

The main goal of the study is to determine whether artificial intelligence can create mathematical and simulation models of the automatic room heating system, and therefore test the abilities of artificial intelligence in the field of engineering sciences. The scientific novelty of the article is the development of a simulation model of an automatic room heating system with relay temperature control using artificial intelligence. To fully and comprehensively disclose the purpose of the study, elementary physical laws are provided that describe the processes of heat transfer and thermal conductivity of the air in a confined space, such as JouleLenz's law or Ohm's law and describe the foundations of the theory of automatic control, and in particular the role of necessary links and negative feedback. Based on the operation of the built models, graphs of the resulting temperature are given, on the basis of which the operating time, the maximum achieved temperatures and the switching time of the heater are based.

The paper presents an approach to automated conceptual database design that combines speech processing and text processing techniques for the automated derivation of conceptual database models from recorded speech. In the first phase, the recorded speech is converted to the corresponding text by applying speech processing techniques. In the second phase, the text is converted to the corresponding conceptual database model by applying text processing techniques. The proposed approach is supported by an online tool named SpeeD, which is the first tool enabling automated derivation of conceptual database models from recorded speech, whereby several different natural languages are supported.

Different types and different size photovoltaic (PV) systems are in use. Assuming that these systems are equipped with some of the: internet of things (IoT) devices, intelligent electronic devices (IED), phasor measurement units (PMUs) and that they are properly communicated with control center, or that inverters in the PV systems contain network interface cards (NICs) which are connected to the control center through network, a solution for infrastructure of the monitoring and management (M&M) system is proposed. The main parts of the system are cloud infrastructure on which supervisory control and data acquisition (SCADA) system is implemented, network that connects all parts of cloud together and enables connections, through proprietary links or service providers networks, to the distributed devices as well as to the inverters at PV sites. Time synchronization between the central part of the SCADA system and devices at PV systems sites enables obtaining precise moments of the events occurrence and timely response. All parts of the SCADA system and network must be secured from the inside and outside threats.

Interaction channels are special opportunities to improve customer satisfaction by offering a consistent problem-solving experience. Contact center employees are the link between the company and the customer. They are responsible for maintaining an appropriate relationship between the company and the customer. So, they are personally responsible for the customer experience. In this paper, we present an objective evaluation method for evaluating customer-agent interaction, i.e., evaluating the effectiveness of the realization of customer requests from calls. The evaluation method is automatic and does not depend on the relationship between the call center manager and the employees. The motivation for evaluating calls stems from the key performance characteristics of a contact center, of which we particularly emphasize service time, first call resolution, handling time, and others.

The perceptual quality of image is affected by distortions during compression, delivery and storage. Distortions also impact automatic image quality assessment (IQA) that needs to be highly correlated with subjective scores. In the absence of reference, which is a typical scenario in practice, no-reference (NR) metrics are necessary for quality measurements. Recently such methods are proposed, and they employ natural scene statistics (NSS). The experimental analysis performed in this paper takes into consideration two fitting or regression models of several NR-IQA metrics relying on different distortion types. The results show quadratic model as promising for making relations in terms of difference mean opinion score and Shannon entropy.

Nowadays, Learning Arabic is perceived as drab by students, with 2.4% finding it very drab, 25.3% finding it drab, and 34.9% finding it quite drab. This research is a development of the MLATS Arabic for easy Arabic language learning. The functional testing showed a 100% success rate for all 7 test cases, and the application performed well on five different computer browsers. The user satisfaction survey yielded a 95% average satisfaction rate for each indicator.

Usage of electrical energy obtained from renewable sources is rapidly increasing. Distributed solar systems will be widely used. The photovoltaic (PV) systems can be used to produce active and reactive power or to compensate reactive power. This paper proposes a solution for monitoring and management of distributed PV systems from the integrated center. The main parts of the system are a cloud infrastructure at the Data Center and Internet of Things (IoT) devices at distributed sites. Also, networks that are used for communication between main parts are an important piece of the proposed solution. While IoT devices continuously send information about electrical parameters of the system and environmental conditions, the inverter, as a part of the PV system, can be controlled by influencing the Maximum Power Point Tracking (MPPT) algorithm operation and inverter functionality.