Edizioni

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 224 (2022): Edizione 1 (March 2022)

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

Impact of Starting Outlier Removal on Accuracy of Time Series Forecasting

Pubblicato online: 08 Mar 2022
Pagine: 1 - 15

Astratto

Abstract

The presence of an outlier at the starting point of a univariate time series negatively influences the forecasting accuracy. The starting outlier is effectively removed only by making it equal to the second time point value. The forecasting accuracy is significantly improved after the removal. The favorable impact of the starting outlier removal on the time series forecasting accuracy is strong. It is the least favorable for time series with exponential rising. In the worst case of a time series, on average only 7 % to 11 % forecasts after the starting outlier removal are worse than they would be without the removal.

Parole chiave

  • time series forecasting
  • outlier
  • ARIMA
  • forecasting accuracy
  • RMSE
  • MaxAE
Open Access

The Analysis of the Strength of the Ship’s Hull After Running Aground

Pubblicato online: 08 Mar 2022
Pagine: 16 - 27

Astratto

Abstract

The article presents a simulation of a ship running aground. It introduces the analytical description, as well as the methodology of carrying out strength calculations when creating engineering tasks related to the topic. It shows the state of stresses and deformations of the hull of a modern minehunter after a collision with the bottom for two immersion depths. Research and development opportunities for future considerations are highlighted in the conclusions.

Parole chiave

  • Destroyer of mines
  • collision with the bottom
  • hull strength
  • finite element method
Open Access

Arima Model Optimal Selection for Time Series Forecasting

Pubblicato online: 08 Mar 2022
Pagine: 28 - 40

Astratto

Abstract

A fast-and-flexible method of ARIMA model optimal selection is suggested for univariate time series forecasting. The method allows obtaining as-highly-accurate-as-possible forecasts automatically. It is based on effectively finding lags by the autocorrelation function of a detrended time series, where the best-fitting polynomial trend is subtracted from the time series. The forecasting quality criteria are the root-mean-square error (RMSE) and the maximum absolute error (MaxAE) allowing to register information about the average inaccuracy and worst outlier. Thus, the ARIMA model optimal selection is performed by simultaneously minimizing RMSE and Max-AE, whereupon the minimum defines the best model. Otherwise, if the minimum does not exist, a combination of minimal-RMSE and minimal-MaxAE ARIMA models is used.

Parole chiave

  • time series forecasting
  • ARIMA
  • model selection
  • forecasting horizon
  • seasonality
  • trend
Open Access

The Assessment of Unmanned Vessel Operation in Heavy Traffic Areas. Case Study of the North Sea Crossing by Unmanned Surface Vessel Sea-Kit

Pubblicato online: 08 Mar 2022
Pagine: 41 - 67

Astratto

Abstract

The continuous development of autonomous and unmanned technology is accelerating the adoption of unmanned vessels for various maritime operations. Despite the technological developments there is still a lack of clear regulatory and organizational frameworks for testing and exploiting the potential of unmanned surface vessels (USVs) in real-world maritime conditions. Such real-world testing becomes ever more complex when operating in multiple nations territorial waters. In May 2019 USV ‘Maxlimer’ crossed the North Sea from the United Kingdom to Belgium and back, carrying goods, to demonstrate the ability of unmanned surface vessels to interact with real marine traffic in an uncontrolled environment. The paper presents this mission in light of the current state of marine autonomy projects as well as the regulatory works conducted by various organizations worldwide.

Parole chiave

  • Unmanned Surface Vessel
  • Autonomous Surface Vessel
  • marine autonomy
  • USV ‘SEA-KIT’
  • collision avoidance
Open Access

Directions of Development of the Autonomous Unmanned Underwater Vehicles. A Review

Pubblicato online: 08 Mar 2022
Pagine: 68 - 79

Astratto

Abstract

In the paper review of unmanned underwater vehicle (AUV) is presented. The description of main systems is depicted with focus on autonomous single vehicle as well as a swarm. As a consequence of development of AUV technology, research centers are focused on issues related to increasing the degree of their autonomy. Nowadays, mostly navigation and communication as well as high-efficient propeller systems are being developed. There are problems linking this issues. Their solutions includes development of new control laws containing algorithms to prevent collisions - for unmanned vehicles with elements of the underwater environment and for several underwater vehicles cooperating with each other in a swarm.

Parole chiave

  • Unmanned Underwater Vehicles
  • Remotely Operated Vehicles
  • Autonomous Underwater
5 Articoli
Open Access

Impact of Starting Outlier Removal on Accuracy of Time Series Forecasting

Pubblicato online: 08 Mar 2022
Pagine: 1 - 15

Astratto

Abstract

The presence of an outlier at the starting point of a univariate time series negatively influences the forecasting accuracy. The starting outlier is effectively removed only by making it equal to the second time point value. The forecasting accuracy is significantly improved after the removal. The favorable impact of the starting outlier removal on the time series forecasting accuracy is strong. It is the least favorable for time series with exponential rising. In the worst case of a time series, on average only 7 % to 11 % forecasts after the starting outlier removal are worse than they would be without the removal.

Parole chiave

  • time series forecasting
  • outlier
  • ARIMA
  • forecasting accuracy
  • RMSE
  • MaxAE
Open Access

The Analysis of the Strength of the Ship’s Hull After Running Aground

Pubblicato online: 08 Mar 2022
Pagine: 16 - 27

Astratto

Abstract

The article presents a simulation of a ship running aground. It introduces the analytical description, as well as the methodology of carrying out strength calculations when creating engineering tasks related to the topic. It shows the state of stresses and deformations of the hull of a modern minehunter after a collision with the bottom for two immersion depths. Research and development opportunities for future considerations are highlighted in the conclusions.

Parole chiave

  • Destroyer of mines
  • collision with the bottom
  • hull strength
  • finite element method
Open Access

Arima Model Optimal Selection for Time Series Forecasting

Pubblicato online: 08 Mar 2022
Pagine: 28 - 40

Astratto

Abstract

A fast-and-flexible method of ARIMA model optimal selection is suggested for univariate time series forecasting. The method allows obtaining as-highly-accurate-as-possible forecasts automatically. It is based on effectively finding lags by the autocorrelation function of a detrended time series, where the best-fitting polynomial trend is subtracted from the time series. The forecasting quality criteria are the root-mean-square error (RMSE) and the maximum absolute error (MaxAE) allowing to register information about the average inaccuracy and worst outlier. Thus, the ARIMA model optimal selection is performed by simultaneously minimizing RMSE and Max-AE, whereupon the minimum defines the best model. Otherwise, if the minimum does not exist, a combination of minimal-RMSE and minimal-MaxAE ARIMA models is used.

Parole chiave

  • time series forecasting
  • ARIMA
  • model selection
  • forecasting horizon
  • seasonality
  • trend
Open Access

The Assessment of Unmanned Vessel Operation in Heavy Traffic Areas. Case Study of the North Sea Crossing by Unmanned Surface Vessel Sea-Kit

Pubblicato online: 08 Mar 2022
Pagine: 41 - 67

Astratto

Abstract

The continuous development of autonomous and unmanned technology is accelerating the adoption of unmanned vessels for various maritime operations. Despite the technological developments there is still a lack of clear regulatory and organizational frameworks for testing and exploiting the potential of unmanned surface vessels (USVs) in real-world maritime conditions. Such real-world testing becomes ever more complex when operating in multiple nations territorial waters. In May 2019 USV ‘Maxlimer’ crossed the North Sea from the United Kingdom to Belgium and back, carrying goods, to demonstrate the ability of unmanned surface vessels to interact with real marine traffic in an uncontrolled environment. The paper presents this mission in light of the current state of marine autonomy projects as well as the regulatory works conducted by various organizations worldwide.

Parole chiave

  • Unmanned Surface Vessel
  • Autonomous Surface Vessel
  • marine autonomy
  • USV ‘SEA-KIT’
  • collision avoidance
Open Access

Directions of Development of the Autonomous Unmanned Underwater Vehicles. A Review

Pubblicato online: 08 Mar 2022
Pagine: 68 - 79

Astratto

Abstract

In the paper review of unmanned underwater vehicle (AUV) is presented. The description of main systems is depicted with focus on autonomous single vehicle as well as a swarm. As a consequence of development of AUV technology, research centers are focused on issues related to increasing the degree of their autonomy. Nowadays, mostly navigation and communication as well as high-efficient propeller systems are being developed. There are problems linking this issues. Their solutions includes development of new control laws containing algorithms to prevent collisions - for unmanned vehicles with elements of the underwater environment and for several underwater vehicles cooperating with each other in a swarm.

Parole chiave

  • Unmanned Underwater Vehicles
  • Remotely Operated Vehicles
  • Autonomous Underwater

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