Rivista e Edizione

Volume 224 (2022): Edizione 1 (March 2022)

Volume 223 (2020): Edizione 4 (December 2020)

Volume 222 (2020): Edizione 3 (September 2020)

Volume 220-221 (2020): Edizione 1-2 (June 2020)

Volume 219 (2019): Edizione 4 (December 2019)

Volume 218 (2019): Edizione 3 (September 2019)

Volume 217 (2019): Edizione 2 (June 2019)

Volume 216 (2019): Edizione 1 (March 2019)

Volume 215 (2018): Edizione 4 (December 2018)

Volume 214 (2018): Edizione 3 (September 2018)

Volume 213 (2018): Edizione 2 (June 2018)

Volume 212 (2018): Edizione 1 (March 2018)

Volume 211 (2017): Edizione 4 (December 2017)

Volume 210 (2017): Edizione 3 (September 2017)

Volume 209 (2017): Edizione 2 (June 2017)

Volume 208 (2017): Edizione 1 (March 2017)

Volume 207 (2016): Edizione 4 (December 2016)

Volume 206 (2016): Edizione 3 (September 2016)

Volume 205 (2016): Edizione 2 (June 2016)

Volume 204 (2016): Edizione 1 (March 2016)

Dettagli della rivista
Formato
Rivista
eISSN
2720-4286
Pubblicato per la prima volta
30 Mar 2016
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

Volume 223 (2020): Edizione 4 (December 2020)

Dettagli della rivista
Formato
Rivista
eISSN
2720-4286
Pubblicato per la prima volta
30 Mar 2016
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

5 Articoli
Open Access

Doppler Effect in 2 × 2 to 4 × 4 Mimo Systems of Wireless Communication with Orthogonal Pilot Channel Estimation

Pubblicato online: 31 Dec 2020
Pagine: 5 - 20

Astratto

Abstract

The Doppler effect in 2×2, 3×3, 4×4 MIMO wireless communication systems with channel estimation is studied. The orthogonal pilot signal approach is used for the channel estimation, where the Hadamard sequences are used for piloting, along with the eight alternative orthogonal sets similar to the Walsh set. MIMO transmissions are simulated for 10 cases of the frame length and pilot symbols per frame by no Doppler shift to 1100 Hz Doppler shift with a step of 100 Hz. Based on the simulation, it is ascertained that MIMO transmissions of shorter frames are less sensitive to the Doppler effect. Despite increasing the number of antennas does not mitigate the Doppler effect, and the bit-error rate performance of 4×4 MIMO systems worsens faster than that of 2×2 MIMO systems, it is better to use the maximum number of antennas. The Doppler effect does badly worsen the performance at highway and express train speeds (100 km/hr, and faster), leaving only possibility to further shorten transmissions. This, however, decreases the data rate, but the respective accuracy-versus-data-rate tradeoff must be acceptable.

Parole chiave

  • wireless communication
  • MIMO
  • Doppler effect
  • transmit-receive antenna pairs
  • bit-error rate
Open Access

Possibilities of Detection of the Jamming of the GNSS Receiver with the Helical Antenna

Pubblicato online: 31 Dec 2020
Pagine: 21 - 37

Astratto

Abstract

Jamming of GNSS signals is lately treated as essential threat for GNSS users. It is especially dangerous in the face of common usage of GPS-like systems in everyday life, and the great belief of everyday users in the truth of devices indications. In spite of the legal prohibition of using them, jammers are commonly accessible, especially in the Internet. Last years showed however that such threat generated purposely also some governments, what is clearly visible in armed conflicts, and during military exercises. Of course this creates the great threat for civilian users if will be in the vicinity.

Applications and services based upon GNSS are becoming increasingly embedded in modern society, so community have now become critically dependent upon their correct operation. This refers positioning first of all, but telecommunications networks, power grids, financial transactions, whole world of logistics are dependant as well. The main users of GNSS, both professional and non-professional smartphones users are not prepared on such situation, and usually have no technical possibilities to detect of jamming. For operators of critical installations, for example seaports, or airfields, the detection of jamming cases is extremely important. It can be provided with special devices, which are usually based on specific antennas, and deep analysis of signal. In this paper experiments in detection of the jamming with helical antennas are discussed

Parole chiave

  • GNSS Receiver
  • helical antenna
Open Access

Tracking of Unmanned Aerial Vehicles Using Computer Vision Methods: A Comparative Analysis

Pubblicato online: 31 Dec 2020
Pagine: 39 - 51

Astratto

Abstract

Tracking of small objects in any given airspace is an integral part of modern security systems. In these systems, there are embedded methods that employ the techniques based on either radio waves, or acoustic signals, or light radiation. The computer vision operation, springing from the light radiation-based technique, has prompted interest in its research. This operation has the advantage of being less expensive than radars and acoustic systems. In addition, it can solve complex security problems by detecting and tracking humans, vehicles, and flying objects. Therefore, this article evaluates the usefulness of the varying computer vision algorithms for tracking of small flying objects.

Parole chiave

  • unmanned aerial vehicle (UAVs)
  • computer vision
  • object tracking
Open Access

Mobile Wheeled Robot to Support the Task of the Alarm Sub - Unit

Pubblicato online: 31 Dec 2020
Pagine: 53 - 66

Astratto

Abstract

The article is a presentation, and detailed description of a mobile, vehicular robot whose task is to support the alarm sub-unit. The project was created in response to the increasing need for monitoring, and recognition of the areas. The robot’s interface was created with the use of integrated development environments for Python. The software implementation was possible due to a minicomputer Raspberry Pi 4 B. The robot’s frame is made out of components which are based on the main chassis. The robot is equipped with compatible sensors and cameras. Those, combined with the interface, are able to give a real-time preview of the area in which the robot is in.

This particular vehicular robot is designed to eliminate the risks caused by tasks of alarm sub-unit, by giving the real-time preview, and analysis of the currently watched area. In addition, it can be used to inspect soldiers in the containment zones, and to help with the identification of unknown objects.

Parole chiave

  • mobile robot
  • raspberry pi
  • phyton
  • controlling a mobile robot
Open Access

An Operational Calculus Model with the (m,n) - Symmetric Difference

Pubblicato online: 31 Dec 2020
Pagine: 67 - 82

Astratto

Abstract

The paper determines a non-classical Bittner operational calculus model, in which the derivative is understood as an -symmetric difference Dm,n{x (k)} := {x (k+m)− x (kn). By considering an operation Dm,n,b{x (k)} := {x (k+m)− b (k)x (kn), the formulated model has been generalized.

Parole chiave

  • operational calculus
  • derivative
  • integrals
  • limit conditions
  • () -symmetric difference
5 Articoli
Open Access

Doppler Effect in 2 × 2 to 4 × 4 Mimo Systems of Wireless Communication with Orthogonal Pilot Channel Estimation

Pubblicato online: 31 Dec 2020
Pagine: 5 - 20

Astratto

Abstract

The Doppler effect in 2×2, 3×3, 4×4 MIMO wireless communication systems with channel estimation is studied. The orthogonal pilot signal approach is used for the channel estimation, where the Hadamard sequences are used for piloting, along with the eight alternative orthogonal sets similar to the Walsh set. MIMO transmissions are simulated for 10 cases of the frame length and pilot symbols per frame by no Doppler shift to 1100 Hz Doppler shift with a step of 100 Hz. Based on the simulation, it is ascertained that MIMO transmissions of shorter frames are less sensitive to the Doppler effect. Despite increasing the number of antennas does not mitigate the Doppler effect, and the bit-error rate performance of 4×4 MIMO systems worsens faster than that of 2×2 MIMO systems, it is better to use the maximum number of antennas. The Doppler effect does badly worsen the performance at highway and express train speeds (100 km/hr, and faster), leaving only possibility to further shorten transmissions. This, however, decreases the data rate, but the respective accuracy-versus-data-rate tradeoff must be acceptable.

Parole chiave

  • wireless communication
  • MIMO
  • Doppler effect
  • transmit-receive antenna pairs
  • bit-error rate
Open Access

Possibilities of Detection of the Jamming of the GNSS Receiver with the Helical Antenna

Pubblicato online: 31 Dec 2020
Pagine: 21 - 37

Astratto

Abstract

Jamming of GNSS signals is lately treated as essential threat for GNSS users. It is especially dangerous in the face of common usage of GPS-like systems in everyday life, and the great belief of everyday users in the truth of devices indications. In spite of the legal prohibition of using them, jammers are commonly accessible, especially in the Internet. Last years showed however that such threat generated purposely also some governments, what is clearly visible in armed conflicts, and during military exercises. Of course this creates the great threat for civilian users if will be in the vicinity.

Applications and services based upon GNSS are becoming increasingly embedded in modern society, so community have now become critically dependent upon their correct operation. This refers positioning first of all, but telecommunications networks, power grids, financial transactions, whole world of logistics are dependant as well. The main users of GNSS, both professional and non-professional smartphones users are not prepared on such situation, and usually have no technical possibilities to detect of jamming. For operators of critical installations, for example seaports, or airfields, the detection of jamming cases is extremely important. It can be provided with special devices, which are usually based on specific antennas, and deep analysis of signal. In this paper experiments in detection of the jamming with helical antennas are discussed

Parole chiave

  • GNSS Receiver
  • helical antenna
Open Access

Tracking of Unmanned Aerial Vehicles Using Computer Vision Methods: A Comparative Analysis

Pubblicato online: 31 Dec 2020
Pagine: 39 - 51

Astratto

Abstract

Tracking of small objects in any given airspace is an integral part of modern security systems. In these systems, there are embedded methods that employ the techniques based on either radio waves, or acoustic signals, or light radiation. The computer vision operation, springing from the light radiation-based technique, has prompted interest in its research. This operation has the advantage of being less expensive than radars and acoustic systems. In addition, it can solve complex security problems by detecting and tracking humans, vehicles, and flying objects. Therefore, this article evaluates the usefulness of the varying computer vision algorithms for tracking of small flying objects.

Parole chiave

  • unmanned aerial vehicle (UAVs)
  • computer vision
  • object tracking
Open Access

Mobile Wheeled Robot to Support the Task of the Alarm Sub - Unit

Pubblicato online: 31 Dec 2020
Pagine: 53 - 66

Astratto

Abstract

The article is a presentation, and detailed description of a mobile, vehicular robot whose task is to support the alarm sub-unit. The project was created in response to the increasing need for monitoring, and recognition of the areas. The robot’s interface was created with the use of integrated development environments for Python. The software implementation was possible due to a minicomputer Raspberry Pi 4 B. The robot’s frame is made out of components which are based on the main chassis. The robot is equipped with compatible sensors and cameras. Those, combined with the interface, are able to give a real-time preview of the area in which the robot is in.

This particular vehicular robot is designed to eliminate the risks caused by tasks of alarm sub-unit, by giving the real-time preview, and analysis of the currently watched area. In addition, it can be used to inspect soldiers in the containment zones, and to help with the identification of unknown objects.

Parole chiave

  • mobile robot
  • raspberry pi
  • phyton
  • controlling a mobile robot
Open Access

An Operational Calculus Model with the (m,n) - Symmetric Difference

Pubblicato online: 31 Dec 2020
Pagine: 67 - 82

Astratto

Abstract

The paper determines a non-classical Bittner operational calculus model, in which the derivative is understood as an -symmetric difference Dm,n{x (k)} := {x (k+m)− x (kn). By considering an operation Dm,n,b{x (k)} := {x (k+m)− b (k)x (kn), the formulated model has been generalized.

Parole chiave

  • operational calculus
  • derivative
  • integrals
  • limit conditions
  • () -symmetric difference

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