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Detalles de la revista
Formato
Revista
eISSN
1407-6179
Publicado por primera vez
20 Mar 2000
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

Volumen 23 (2022): Edición 1 (February 2022)

Detalles de la revista
Formato
Revista
eISSN
1407-6179
Publicado por primera vez
20 Mar 2000
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

10 Artículos
Acceso abierto

Modeling of Mobile and Fixed Broadband Subscriptions of Countries with Fractional Calculus

Publicado en línea: 18 Feb 2022
Páginas: 1 - 10

Resumen

Abstract

Today, operators have become the resource of telecommunications data. Therefore, knowledge about subscriptions is easily available for most countries. In recent years, high-speed mobile internet access subscriptions are also increasing rapidly. There are two important subscriptions reviewed by The International Telecommunication Union (ITU): mobile broadband (MBB) subscriptions and Fixed broadband (FBB) subscriptions. In this study, we proposed an original mathematical model employing the fractional analysis theory and evaluate its validity by modeling the mobile broadband and fixed broadband subscriptions of six countries including France, Italy, Turkey, Germany, Spain, and the U.K. Later, we compared the Fractional Model we developed with the Polynomial Model. The results show that the Fractional Model is superior to the conventional Polynomial Model in modeling broadband subscriptions. For all selected countries, our proposed Fractional approach outperforms conventional polynomial regression. For all investigation categories, on average, the fractional approach works better by at least 10% and at most 30%.

Palabras clave

  • Fractional calculus
  • mobile and fixed broadband
  • broadband subscriptions
  • MAPE
  • mathematical modeling
Acceso abierto

Crash Distribution Dataset: Development and Validation for the Undivided Rural Roads in Oromia, Ethiopia

Publicado en línea: 18 Feb 2022
Páginas: 11 - 24

Resumen

Abstract

Predicting the number of crashes that may occur as a result of specific highway features is critical in evaluating different treatment or design alternatives. Since different highway geometric characteristics can influence crash distribution datasets, Highway Safety Manual’s (HSM’s) predictive method encourages users to predict crashes based on their severity and collision type proportions. This study used crash data from rural two-way two-lane road segments in the Oromia region over seven years to develop Oromia’s fixed crash distribution dataset on Interactive Highway Safety Design Model (IHSDM) software. The crash distribution dataset has two parts; the crash severity proportions and the collision type percentages. The developed Oromia’s fixed crash distribution dataset was compared and validated against the default HSM crash configuration. As a result, the Crash Prediction Model (CPM) evaluation results confirmed that the developed crash severity proportion (the first part of the crash distribution dataset) estimates are more accurate and closer to the observed values. Furthermore, the findings show that crashes in the Oromia region are severer than in the states where the HSM crash configuration was developed. According to the second part of the crash distribution dataset evaluation (collision type percentage), the developed fixed crash distribution dataset outperforms the default HSM configuration in most collision type proportions, but not in all. For instance, from the ten collision type proportions developed, Right-Angle and sides-wipe collision proportions are predicted more precisely by the default HSM configuration. This points to the need for developing collision type proportion (the second part of the crash distribution dataset) as a function rather than a fixed configuration for a better result, based on the availability of complete crash data (i.e. crash location). In general, the study revealed that in order to exploit the full potential of HSM’s predictive approach, researchers must develop a jurisdiction crash distribution dataset using local crash data. The methodology demonstrated in this study to develop the jurisdiction’s crash distribution dataset has been validated as true thus, safety practitioners are encouraged to adopt it.

Palabras clave

  • crash distribution dataset
  • crash prediction model
  • HSM
  • IHSDM
  • Oromia
  • rural roads
Acceso abierto

A Kalman Filter Based Hybrid Routing Protocol for Efficient Vehicle Connectivity and Traffic Management

Publicado en línea: 18 Feb 2022
Páginas: 25 - 32

Resumen

Abstract

The geographic routing protocols in Vehicular Ad Hoc Networks (VANETs) are contemplated as most efficacious protocols. Though, such types of protocols communicate a huge quantity of data that influence the network connectivity negatively. Also, out of bound issue is the second major disadvantage of geographic routing protocols. To provide a solution to these impediments, a novel K-PGRP (Kalman filter-Predictive Geographic Routing Protocol) routing protocol is proposed in this paper. K-PGRP is an improvement to PGRP (Predictive Geographic Routing Protocol) routing protocol and wields Kalman filter as a prediction module in PGRP routing protocol in order to anticipate the neighbor location and to select the propitious neighbor for advancing packets in both urban and highway framework which leads to efficient connectivity in the network and improves road safety. K-PGRP is then compared with PGRP, GPSR (Greedy Perimeter Stateless Routing) and GPCR (Greedy Perimeter Coordinator Routing) routing protocols in terms of throughput and packet delivery ratio metrics and outperformed all the simulation cases. The simulations were performed on MATLAB R2018a along with traffic simulator SUMO.

Palabras clave

  • Routing
  • Kalman filter
  • IoV
  • prediction
  • connectivity
Acceso abierto

Reliable and Seamless Communications of Networked IAV in Container Terminal Using UAV Technology

Publicado en línea: 18 Feb 2022
Páginas: 33 - 47

Resumen

Abstract

Managing container loading and unloading operations at a container terminal using Intelligent Autonomous Vehicle (IAV) is challenging, especially at intersections in the yard, which are often inevitable. For ensuring efficient and accident-free management of these intersections, the IAV must cooperate by exchanging messages. Due to signal obstruction at these intersections, indirect communication is established through an additional relay node to ensure reliable communication. This paper proposes distributed approach using Unmanned Aerial Vehicle (UAV) connectivity to avoid collision and deadlock between IAV at intersections. Due to the obstacles formed by stacked containers blocking the radio transmissions, the proposed algorithm automatically switches the ongoing communication through the UAV to ensure successful communication at intersections. Thus, the idea of introducing UAV as communication relay in a container terminal is an interesting solution that we have adopted in this work. Simulation techniques are used to evaluate our proposal. The obtained results confirm that our UAV-based approach ensures reliable communication and automated intersections management in the yard while further ensuring the safety of IAV traffic.

Palabras clave

  • UAV
  • wireless communication
  • IAV
  • intersection
  • ACT
  • distributed algorithm
Acceso abierto

Method of Improving Incomplete Spatial-Temporal Data in Inland Navigation, on the Basis of Industrial Camera Images – West Oder River Case Study

Publicado en línea: 18 Feb 2022
Páginas: 48 - 61

Resumen

Abstract

Main aim of the paper is to use a single non-metric camera to support the determination of the position of. Authors propose to use the existing infrastructure of CCTV cameras mounted on bridges and wharves to determine the position of inland waterway vessels. Image from cameras giving the pixel coordinates of moving object is transformed to the geodetic data domain using a modified projective transformation method. Novel approach is to use of Sequential Projection Transformation (SPT) which additionally uses virtual reference points. The transformation coefficients calculated using the virtual points are used to determine the position of the vessels and are also simultaneously used to calibrate the industrial camera. The method has been verified under real conditions, and the results obtained are average 30% more accurate compared to the traditionally used projective transformation using a small number of real points.

Palabras clave

  • freight transport
  • geodesy
  • image processing
  • spatial data
  • inland navigation
  • industrial camera
Acceso abierto

A New Method to Boost VoIP Performance Over IPv6 Networks

Publicado en línea: 18 Feb 2022
Páginas: 62 - 72

Resumen

Abstract

The demands on virtual communication have increased noticeably during the COVID-19 pandemic lockdown. As an essential part of virtual communication, VoIP should be promoted to achieve the desired level of performance. One critical area investigated in VoIP is the bandwidth utilization (BWU) of the VoIP over IPv6 networks. Enhancing BWU will impact call capacity and quality; it increases call capacity and boosts call quality. Unfortunately, a considerable amount of bandwidth is wasted when running VoIP over IPv6 networks. This is due to the large size of the IPv6 header and the small size of the speech frame. This paper proposes a new method to handle the inefficient BWU when running VoIP over IPv6 networks. The proposed method combines multiplexing multiple VoIP packets in one IPv6 header and using the superfluous fields to carry a portion of the speech frame. Therefore, the proposed is called packet multiplexing and carrier fields (PMCF). Investigation of the PCMF method has been done using four metrics to measure the promotion in BWU, namely calls capacity, header size, bandwidth saving, and speech frame shortening metrics. With the four metrics, the PMCF method has outperformed the comparable methods. For instance, the call capacity has been promoted by up to 269% compared to the typical IPv6 method in the tested scenarios. Therefore, the PMCF method is a feasible solution to facilitate the BWU of VoIP when running VoIP over IPv6 networks.

Palabras clave

  • VoIP
  • bandwidth utilization
  • IPv6
  • VoIP performance
Acceso abierto

Efficiency of Ship Operation in Transportation of Oversized and Heavy Cargo by Optimizing the Speed Mode Considering the Impact of Weather Conditions

Publicado en línea: 18 Feb 2022
Páginas: 73 - 80

Resumen

Abstract

Prior to commencing the voyage planning procedure, the entire navigation area on the forthcoming passage should be divided into several sections, depending on various factors, such as traffic density, restricted depths, availability of ship reporting systems, hydrometeorological conditions, high risk navigation areas in order to outline measures to ensure the safety of ship’s navigation. In addition, these factors have direct impact on the ship’s speed during the voyage. On the other hand, slow steaming can reduce fuel consumption on the same section of the route by 10-15%. Reducing the ship’s speed can significantly minimize its operating costs. However, when choosing economically feasible ship’s speed it should be kept in mind that reducing the speed can lead to a significant decrease in the number of voyages per year and, consequently, to the reduction of annual freight income. Therefore, a practically important and relevant problem is the necessity to find the speed of ship operation, which will provide a balance between economical fuel consumption and profits from ship operation. The classic approach to optimizing the speed mode of ships is based on the cubic dependence of fuel consumption on speed. Therefore, depending on the distance between ports, the duration of the voyage and the conditions for the time of arrival of the ship to the port, in the modern publications were proposed approaches to the optimization of the speed mode, based on the additional income or time-charter equivalent.

Palabras clave

  • Ship speed optimization
  • Oversized and heavy cargo
  • Route specifics
  • Weather conditions
  • Time-charter equivalent
Acceso abierto

Competence of Bus Rapid Transit Systems Coupled with Transit Signal Priority at Signalized Junctions

Publicado en línea: 18 Feb 2022
Páginas: 81 - 92

Resumen

Abstract

One of the primary causes of poor public transport performance is delays at intersections. Among the efficient and sustainable solutions to boost mass transportation performance, Bus Rapid Transit (BRT) consists of infrastructures integrating dedicated bus lanes and smart operational service with different ITS technologies like Transit Signal Priority (TSP). This research studies the competence of buses operating on junctions of the BRT corridor where they have Signal Priority on the dedicated lane. The studied intersection is located around the center of the Addis Ababa BRT-B2 line, which is relatively gentle grade and characterized by the high traffic and pedestrian volume. Microscopic models were created for the chosen intersection, along with possible calibration and validation; moreover, a statistical comparison was performed to evaluate different scenarios with the goal of displaying the deployment benefits. To assess the performance of BRT buses and their overall influence on general traffic, scenarios with and without TSP were evaluated. PTV VISSIM and the VisVAP add-on simulation program were used to examine TSP alternatives. Incorporating TSP reduced the travel time by up to 4.78% in the priority direction, the average travel speed increased by 7.25%, and the queue length also reduced by a maximum of 6%, whereas in the non-priority direction, the queue length increased by a maximum of 2.5%. Moreover, the overall average passenger delay has reduced by an average amount of 15%. One of the simplest ways to improve transit performance could be signal priority strategies, which has a minor influence on the general traffic.

Palabras clave

  • Bus rapid transit
  • delay
  • ITS
  • PTV VISSIM
  • public transport performance
  • transit signal priority
Acceso abierto

Occupancy Estimation at Bus Stops Through Wi-Fi Connectivity Assessment – A Study in Guayaquil City

Publicado en línea: 18 Feb 2022
Páginas: 93 - 101

Resumen

Abstract

Guayaquil is one of the most congested cities on the American continent. Several users cannot access on-time transport service according to the demand requested at bus stops. This work presents a simulation of the Wi-Fi technology to determine the number of users present at a bus stop. The objective is to know an estimation of them in different time intervals throughout the day, which could be useful for several actions, e.g., to set up a better distribution of transportation schedules or to place the bus stops in more demanding sites by users. The methodology included simulation scenarios for user counting at the bus stops. The results depicted that Wi-Fi technology performed suitable even in high-level attenuation scenarios.

Palabras clave

  • Bus stops
  • design thinking
  • transport system
  • user counting
  • Wi-Fi assessment
  • Wi-Fi simulation
Acceso abierto

Ammonia as Clean Shipping Fuel for the Baltic Sea Region

Publicado en línea: 18 Feb 2022
Páginas: 102 - 112

Resumen

Abstract

The international shipping industry transports about 90 per cent of the global trade volume and is responsible for only two per cent of the anthropogenic carbon dioxide emissions. Consequently, the shipping sector is considered as an environmentally friendly transport mode. Nevertheless, global shipping can also improve its environmental footprint. So that in recent years clean shipping initiatives have been placed on the political agenda with the implementation of the Sulphur Emission Control Area (SECA) and Nitrogen Emission Control Area (ECA) regulations and the Global Cap. The next target of the International Maritime Organisation (IMO) in the sequel of the Paris Agreement of climate protection is dedicated to reduction of the Greenhouse Gas (GHG) emissions by up to 50 % until the year 2050.

The paper investigates and discusses the research questions to what extent ammonia can be used in Baltic Sea Region (BSR) to propel merchant vessels and how ammonia can fulfil future demands under technical, economic and infrastructural aspects to become the green fuel for the Baltic Sea Region (BSR) shipping industry. The study benchmarks the properties of ammonia as marine fuel against Marine Gas Oil (MGO) and Liquified Natural Gas (LNG). The research is based on secondary data analysis that is complemented by expert interviews and case studies, and the results are empirically validated by data that were collected during the EU projects “EnviSuM”, “GoLNG”, “CSHIPP” and “Connect2SmallPorts” that took place within the last four years in the BSR.

Palabras clave

  • Clean Shipping
  • Ammonia
  • Alternative Fuels
  • BSR
  • Decarbonisation
10 Artículos
Acceso abierto

Modeling of Mobile and Fixed Broadband Subscriptions of Countries with Fractional Calculus

Publicado en línea: 18 Feb 2022
Páginas: 1 - 10

Resumen

Abstract

Today, operators have become the resource of telecommunications data. Therefore, knowledge about subscriptions is easily available for most countries. In recent years, high-speed mobile internet access subscriptions are also increasing rapidly. There are two important subscriptions reviewed by The International Telecommunication Union (ITU): mobile broadband (MBB) subscriptions and Fixed broadband (FBB) subscriptions. In this study, we proposed an original mathematical model employing the fractional analysis theory and evaluate its validity by modeling the mobile broadband and fixed broadband subscriptions of six countries including France, Italy, Turkey, Germany, Spain, and the U.K. Later, we compared the Fractional Model we developed with the Polynomial Model. The results show that the Fractional Model is superior to the conventional Polynomial Model in modeling broadband subscriptions. For all selected countries, our proposed Fractional approach outperforms conventional polynomial regression. For all investigation categories, on average, the fractional approach works better by at least 10% and at most 30%.

Palabras clave

  • Fractional calculus
  • mobile and fixed broadband
  • broadband subscriptions
  • MAPE
  • mathematical modeling
Acceso abierto

Crash Distribution Dataset: Development and Validation for the Undivided Rural Roads in Oromia, Ethiopia

Publicado en línea: 18 Feb 2022
Páginas: 11 - 24

Resumen

Abstract

Predicting the number of crashes that may occur as a result of specific highway features is critical in evaluating different treatment or design alternatives. Since different highway geometric characteristics can influence crash distribution datasets, Highway Safety Manual’s (HSM’s) predictive method encourages users to predict crashes based on their severity and collision type proportions. This study used crash data from rural two-way two-lane road segments in the Oromia region over seven years to develop Oromia’s fixed crash distribution dataset on Interactive Highway Safety Design Model (IHSDM) software. The crash distribution dataset has two parts; the crash severity proportions and the collision type percentages. The developed Oromia’s fixed crash distribution dataset was compared and validated against the default HSM crash configuration. As a result, the Crash Prediction Model (CPM) evaluation results confirmed that the developed crash severity proportion (the first part of the crash distribution dataset) estimates are more accurate and closer to the observed values. Furthermore, the findings show that crashes in the Oromia region are severer than in the states where the HSM crash configuration was developed. According to the second part of the crash distribution dataset evaluation (collision type percentage), the developed fixed crash distribution dataset outperforms the default HSM configuration in most collision type proportions, but not in all. For instance, from the ten collision type proportions developed, Right-Angle and sides-wipe collision proportions are predicted more precisely by the default HSM configuration. This points to the need for developing collision type proportion (the second part of the crash distribution dataset) as a function rather than a fixed configuration for a better result, based on the availability of complete crash data (i.e. crash location). In general, the study revealed that in order to exploit the full potential of HSM’s predictive approach, researchers must develop a jurisdiction crash distribution dataset using local crash data. The methodology demonstrated in this study to develop the jurisdiction’s crash distribution dataset has been validated as true thus, safety practitioners are encouraged to adopt it.

Palabras clave

  • crash distribution dataset
  • crash prediction model
  • HSM
  • IHSDM
  • Oromia
  • rural roads
Acceso abierto

A Kalman Filter Based Hybrid Routing Protocol for Efficient Vehicle Connectivity and Traffic Management

Publicado en línea: 18 Feb 2022
Páginas: 25 - 32

Resumen

Abstract

The geographic routing protocols in Vehicular Ad Hoc Networks (VANETs) are contemplated as most efficacious protocols. Though, such types of protocols communicate a huge quantity of data that influence the network connectivity negatively. Also, out of bound issue is the second major disadvantage of geographic routing protocols. To provide a solution to these impediments, a novel K-PGRP (Kalman filter-Predictive Geographic Routing Protocol) routing protocol is proposed in this paper. K-PGRP is an improvement to PGRP (Predictive Geographic Routing Protocol) routing protocol and wields Kalman filter as a prediction module in PGRP routing protocol in order to anticipate the neighbor location and to select the propitious neighbor for advancing packets in both urban and highway framework which leads to efficient connectivity in the network and improves road safety. K-PGRP is then compared with PGRP, GPSR (Greedy Perimeter Stateless Routing) and GPCR (Greedy Perimeter Coordinator Routing) routing protocols in terms of throughput and packet delivery ratio metrics and outperformed all the simulation cases. The simulations were performed on MATLAB R2018a along with traffic simulator SUMO.

Palabras clave

  • Routing
  • Kalman filter
  • IoV
  • prediction
  • connectivity
Acceso abierto

Reliable and Seamless Communications of Networked IAV in Container Terminal Using UAV Technology

Publicado en línea: 18 Feb 2022
Páginas: 33 - 47

Resumen

Abstract

Managing container loading and unloading operations at a container terminal using Intelligent Autonomous Vehicle (IAV) is challenging, especially at intersections in the yard, which are often inevitable. For ensuring efficient and accident-free management of these intersections, the IAV must cooperate by exchanging messages. Due to signal obstruction at these intersections, indirect communication is established through an additional relay node to ensure reliable communication. This paper proposes distributed approach using Unmanned Aerial Vehicle (UAV) connectivity to avoid collision and deadlock between IAV at intersections. Due to the obstacles formed by stacked containers blocking the radio transmissions, the proposed algorithm automatically switches the ongoing communication through the UAV to ensure successful communication at intersections. Thus, the idea of introducing UAV as communication relay in a container terminal is an interesting solution that we have adopted in this work. Simulation techniques are used to evaluate our proposal. The obtained results confirm that our UAV-based approach ensures reliable communication and automated intersections management in the yard while further ensuring the safety of IAV traffic.

Palabras clave

  • UAV
  • wireless communication
  • IAV
  • intersection
  • ACT
  • distributed algorithm
Acceso abierto

Method of Improving Incomplete Spatial-Temporal Data in Inland Navigation, on the Basis of Industrial Camera Images – West Oder River Case Study

Publicado en línea: 18 Feb 2022
Páginas: 48 - 61

Resumen

Abstract

Main aim of the paper is to use a single non-metric camera to support the determination of the position of. Authors propose to use the existing infrastructure of CCTV cameras mounted on bridges and wharves to determine the position of inland waterway vessels. Image from cameras giving the pixel coordinates of moving object is transformed to the geodetic data domain using a modified projective transformation method. Novel approach is to use of Sequential Projection Transformation (SPT) which additionally uses virtual reference points. The transformation coefficients calculated using the virtual points are used to determine the position of the vessels and are also simultaneously used to calibrate the industrial camera. The method has been verified under real conditions, and the results obtained are average 30% more accurate compared to the traditionally used projective transformation using a small number of real points.

Palabras clave

  • freight transport
  • geodesy
  • image processing
  • spatial data
  • inland navigation
  • industrial camera
Acceso abierto

A New Method to Boost VoIP Performance Over IPv6 Networks

Publicado en línea: 18 Feb 2022
Páginas: 62 - 72

Resumen

Abstract

The demands on virtual communication have increased noticeably during the COVID-19 pandemic lockdown. As an essential part of virtual communication, VoIP should be promoted to achieve the desired level of performance. One critical area investigated in VoIP is the bandwidth utilization (BWU) of the VoIP over IPv6 networks. Enhancing BWU will impact call capacity and quality; it increases call capacity and boosts call quality. Unfortunately, a considerable amount of bandwidth is wasted when running VoIP over IPv6 networks. This is due to the large size of the IPv6 header and the small size of the speech frame. This paper proposes a new method to handle the inefficient BWU when running VoIP over IPv6 networks. The proposed method combines multiplexing multiple VoIP packets in one IPv6 header and using the superfluous fields to carry a portion of the speech frame. Therefore, the proposed is called packet multiplexing and carrier fields (PMCF). Investigation of the PCMF method has been done using four metrics to measure the promotion in BWU, namely calls capacity, header size, bandwidth saving, and speech frame shortening metrics. With the four metrics, the PMCF method has outperformed the comparable methods. For instance, the call capacity has been promoted by up to 269% compared to the typical IPv6 method in the tested scenarios. Therefore, the PMCF method is a feasible solution to facilitate the BWU of VoIP when running VoIP over IPv6 networks.

Palabras clave

  • VoIP
  • bandwidth utilization
  • IPv6
  • VoIP performance
Acceso abierto

Efficiency of Ship Operation in Transportation of Oversized and Heavy Cargo by Optimizing the Speed Mode Considering the Impact of Weather Conditions

Publicado en línea: 18 Feb 2022
Páginas: 73 - 80

Resumen

Abstract

Prior to commencing the voyage planning procedure, the entire navigation area on the forthcoming passage should be divided into several sections, depending on various factors, such as traffic density, restricted depths, availability of ship reporting systems, hydrometeorological conditions, high risk navigation areas in order to outline measures to ensure the safety of ship’s navigation. In addition, these factors have direct impact on the ship’s speed during the voyage. On the other hand, slow steaming can reduce fuel consumption on the same section of the route by 10-15%. Reducing the ship’s speed can significantly minimize its operating costs. However, when choosing economically feasible ship’s speed it should be kept in mind that reducing the speed can lead to a significant decrease in the number of voyages per year and, consequently, to the reduction of annual freight income. Therefore, a practically important and relevant problem is the necessity to find the speed of ship operation, which will provide a balance between economical fuel consumption and profits from ship operation. The classic approach to optimizing the speed mode of ships is based on the cubic dependence of fuel consumption on speed. Therefore, depending on the distance between ports, the duration of the voyage and the conditions for the time of arrival of the ship to the port, in the modern publications were proposed approaches to the optimization of the speed mode, based on the additional income or time-charter equivalent.

Palabras clave

  • Ship speed optimization
  • Oversized and heavy cargo
  • Route specifics
  • Weather conditions
  • Time-charter equivalent
Acceso abierto

Competence of Bus Rapid Transit Systems Coupled with Transit Signal Priority at Signalized Junctions

Publicado en línea: 18 Feb 2022
Páginas: 81 - 92

Resumen

Abstract

One of the primary causes of poor public transport performance is delays at intersections. Among the efficient and sustainable solutions to boost mass transportation performance, Bus Rapid Transit (BRT) consists of infrastructures integrating dedicated bus lanes and smart operational service with different ITS technologies like Transit Signal Priority (TSP). This research studies the competence of buses operating on junctions of the BRT corridor where they have Signal Priority on the dedicated lane. The studied intersection is located around the center of the Addis Ababa BRT-B2 line, which is relatively gentle grade and characterized by the high traffic and pedestrian volume. Microscopic models were created for the chosen intersection, along with possible calibration and validation; moreover, a statistical comparison was performed to evaluate different scenarios with the goal of displaying the deployment benefits. To assess the performance of BRT buses and their overall influence on general traffic, scenarios with and without TSP were evaluated. PTV VISSIM and the VisVAP add-on simulation program were used to examine TSP alternatives. Incorporating TSP reduced the travel time by up to 4.78% in the priority direction, the average travel speed increased by 7.25%, and the queue length also reduced by a maximum of 6%, whereas in the non-priority direction, the queue length increased by a maximum of 2.5%. Moreover, the overall average passenger delay has reduced by an average amount of 15%. One of the simplest ways to improve transit performance could be signal priority strategies, which has a minor influence on the general traffic.

Palabras clave

  • Bus rapid transit
  • delay
  • ITS
  • PTV VISSIM
  • public transport performance
  • transit signal priority
Acceso abierto

Occupancy Estimation at Bus Stops Through Wi-Fi Connectivity Assessment – A Study in Guayaquil City

Publicado en línea: 18 Feb 2022
Páginas: 93 - 101

Resumen

Abstract

Guayaquil is one of the most congested cities on the American continent. Several users cannot access on-time transport service according to the demand requested at bus stops. This work presents a simulation of the Wi-Fi technology to determine the number of users present at a bus stop. The objective is to know an estimation of them in different time intervals throughout the day, which could be useful for several actions, e.g., to set up a better distribution of transportation schedules or to place the bus stops in more demanding sites by users. The methodology included simulation scenarios for user counting at the bus stops. The results depicted that Wi-Fi technology performed suitable even in high-level attenuation scenarios.

Palabras clave

  • Bus stops
  • design thinking
  • transport system
  • user counting
  • Wi-Fi assessment
  • Wi-Fi simulation
Acceso abierto

Ammonia as Clean Shipping Fuel for the Baltic Sea Region

Publicado en línea: 18 Feb 2022
Páginas: 102 - 112

Resumen

Abstract

The international shipping industry transports about 90 per cent of the global trade volume and is responsible for only two per cent of the anthropogenic carbon dioxide emissions. Consequently, the shipping sector is considered as an environmentally friendly transport mode. Nevertheless, global shipping can also improve its environmental footprint. So that in recent years clean shipping initiatives have been placed on the political agenda with the implementation of the Sulphur Emission Control Area (SECA) and Nitrogen Emission Control Area (ECA) regulations and the Global Cap. The next target of the International Maritime Organisation (IMO) in the sequel of the Paris Agreement of climate protection is dedicated to reduction of the Greenhouse Gas (GHG) emissions by up to 50 % until the year 2050.

The paper investigates and discusses the research questions to what extent ammonia can be used in Baltic Sea Region (BSR) to propel merchant vessels and how ammonia can fulfil future demands under technical, economic and infrastructural aspects to become the green fuel for the Baltic Sea Region (BSR) shipping industry. The study benchmarks the properties of ammonia as marine fuel against Marine Gas Oil (MGO) and Liquified Natural Gas (LNG). The research is based on secondary data analysis that is complemented by expert interviews and case studies, and the results are empirically validated by data that were collected during the EU projects “EnviSuM”, “GoLNG”, “CSHIPP” and “Connect2SmallPorts” that took place within the last four years in the BSR.

Palabras clave

  • Clean Shipping
  • Ammonia
  • Alternative Fuels
  • BSR
  • Decarbonisation

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