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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1407-6179
Pierwsze wydanie
20 Mar 2000
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 18 (2017): Zeszyt 2 (June 2017)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1407-6179
Pierwsze wydanie
20 Mar 2000
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

7 Artykułów
Otwarty dostęp

Assessment of the Capacity of Roads Weaving Segments

Data publikacji: 26 Apr 2017
Zakres stron: 101 - 106

Abstrakt

Abstract

Driving style is affected by development of cars and it has influence on the capacity of designed elements of roads and highways. Therefore, based on research, more accurate methods for assessing the capacity of road infrastructure are being developed. This paper presents the results of the research of weaving segments. It is focused on capacity assessment of these sections within the Czech Republic. Attention is focused especially on weaving segments in urban conditions with high traffic volume and on road sections with a speed limit less than 80 km per hour. Research verified the possibility of using these purposes by existing methodology developed for roads with a speed limit up to 80 km per hour.

Słowa kluczowe

  • weaving segment
  • capacity assessment
  • weaving segment operation
  • level of service (LOS)
Otwarty dostęp

First Cost Calculation Methods for Road Freight Transport Activity

Data publikacji: 26 Apr 2017
Zakres stron: 107 - 117

Abstrakt

Abstract

The transport activity is one of the most expensive processes in the supply chain. Forwarding and transport companies focuses on the optimization of transportation and the reduction of transport costs.

The goal of this study is to develop a method which calculate the first (prime) cost of a given transport task more precisely than the state of the art practices. In practice the calculation of transport fee depends on the individual estimation methods of the transport managers, which could result losses for the company.

In this study the elaborated calculation method for total first cost is detailed for three types of fulfilment of transport tasks. The most common type of achievement is, when “own vehicle is used with own driver”. A software was also developed for this case based on the elaborated method.

Based on the calculations of our software, the first cost can be defined quickly and precisely to realize higher profit.

Słowa kluczowe

  • road freight transport
  • first cost
  • calculation
  • profit maximization
  • software
Otwarty dostęp

Introducing the Methodology of Transplanting a New National Speed Management Strategy

Data publikacji: 26 Apr 2017
Zakres stron: 118 - 127

Abstrakt

Abstract

This paper explains the most important methodological steps of introducing a new speed management strategy. The development of a speed monitoring system with a long term effect on the progress of road safety, makes it necessary to identify its strategic goals, main functions and system components. The strategy should investigate current speed management methods, regulation framework of road signs, tendencies represented by statistics, enforcement campaigns, control equipment, and last but not least the penalty system. Assessment of the applied speed enforcement practices and framework should involve the revision of the recently operating institutional, legal and technical framework of speed enforcement structure.

Słowa kluczowe

  • speed management strategy
  • strategy adaptation
  • road safety
  • strategic element
Otwarty dostęp

Hierarchical Agglomerative Clustering Schemes for Energy-Efficiency in Wireless Sensor Networks

Data publikacji: 26 Apr 2017
Zakres stron: 128 - 138

Abstrakt

Abstract

Extending the lifetime of wireless sensor networks (WSNs) while delivering the expected level of service remains a hot research topic. Clustering has been identified in the literature as one of the primary means to save communication energy. In this paper, we argue that hierarchical agglomerative clustering (HAC) provides a suitable foundation for designing highly energy efficient communication protocols for WSNs. To this end, we study a new mechanism for selecting cluster heads (CHs) based both on the physical location of the sensors and their residual energy. Furthermore, we study different patterns of communications between the CHs and the base station depending on the possible transmission ranges and the ability of the sensors to act as traffic relays. Simulation results show that our proposed clustering and communication schemes outperform well-knows existing approaches by comfortable margins. In particular, networks lifetime is increased by more than 60% compared to LEACH and HEED, and by more than 30% compared to K-means clustering.

Słowa kluczowe

  • WSNs
  • hierarchical agglomerative clustering
  • cluster head
  • energy-efficiency
Otwarty dostęp

Models and Algorithms for Estimation and Minimization of the Risks Associated with Dredging

Data publikacji: 26 Apr 2017
Zakres stron: 139 - 145

Abstrakt

Abstract

There are a lot of models and algorithms to minimize risks during dredging operations and they are not without drawbacks. The paper describes the authors’ approach to solving this problem. Mathematical models are proposed and on their basis software is developed. Methods of the risk theory are used to minimize the risks. In this paper a consequence of influence refers to the deviation from the goal expressed in the expected results and the deviation of certain criterion factors. In this case, we mean any measure of quality. In its turn, risk factors reduce criterion factors. These factors are divided into categories - general transportation risks and risks of transporting ground. In these categories, one may derive the following risks - incidents at transport resulting from the impact of a set of random factors including the human one. For risk analysis and management, in addition to identifying critical chains of risk situations, the stochastic model for evaluating the chains is set forth. In order to implement this algorithm, the mathematical package Maple is used, which allows for conducting the required calculations with a software package including the Graph Theory. The paper presents fragments of the code listing.

Słowa kluczowe

  • dredging operations
  • risks assessment
  • risks minimization
Otwarty dostęp

GNSS Positioning Performance Analysis Using PSO-RBF Estimation Model

Data publikacji: 26 Apr 2017
Zakres stron: 146 - 154

Abstrakt

Abstract

Positioning solutions need to be more precise and available. The most frequent method used nowadays includes a GPS receiver, sometimes supported by other sensors. Generally, GPS and GNSS suffer from spreading perturbations that produce biases on pseudo-range measurements. With a view to optimize the use of the satellites received, we offer a positioning algorithm with pseudo range error modelling with the contribution of an appropriate filtering process. Extended Kalman Filter, The Rao- Blackwellized filter are among the most widely used algorithms to predict errors and to filter the high frequency noise. This paper describes a new method of estimating the pseudo-range errors based on the PSO-RBF model which achieves an optimal training criterion. This model is appropriate of its method to predict the GPS corrections for accurate positioning, it reduce the positioning errors at high velocities by more than 50% compared to the RLS or EKF methods.

Słowa kluczowe

  • GNSS
  • pseudo-range
  • filtering
  • prediction
  • PSO-RBF
Otwarty dostęp

Hierarchical Method of Inter-Area Fast Rerouting

Data publikacji: 26 Apr 2017
Zakres stron: 155 - 167

Abstrakt

Abstract

In this paper, in order to increase the scalability and fault-tolerance of routing solutions the hierarchical method of inter-area fast rerouting in communication networks was presented. The method is based on the decomposed representation of the flow-based routing model with the introduction of the area interaction conditions to ensure connectivity of the inter-area routes. The model includes conditions for border routers protection, adapted for both single path and multipath routing. During the research it was established that the efficiency of the proposed method in terms of the speed of the coordinating procedure convergence was most influenced by the number of border routers and the implemented routing strategy.

Słowa kluczowe

  • inter-area routing
  • hierarchy
  • fault-tolerance
  • fast rerouting
7 Artykułów
Otwarty dostęp

Assessment of the Capacity of Roads Weaving Segments

Data publikacji: 26 Apr 2017
Zakres stron: 101 - 106

Abstrakt

Abstract

Driving style is affected by development of cars and it has influence on the capacity of designed elements of roads and highways. Therefore, based on research, more accurate methods for assessing the capacity of road infrastructure are being developed. This paper presents the results of the research of weaving segments. It is focused on capacity assessment of these sections within the Czech Republic. Attention is focused especially on weaving segments in urban conditions with high traffic volume and on road sections with a speed limit less than 80 km per hour. Research verified the possibility of using these purposes by existing methodology developed for roads with a speed limit up to 80 km per hour.

Słowa kluczowe

  • weaving segment
  • capacity assessment
  • weaving segment operation
  • level of service (LOS)
Otwarty dostęp

First Cost Calculation Methods for Road Freight Transport Activity

Data publikacji: 26 Apr 2017
Zakres stron: 107 - 117

Abstrakt

Abstract

The transport activity is one of the most expensive processes in the supply chain. Forwarding and transport companies focuses on the optimization of transportation and the reduction of transport costs.

The goal of this study is to develop a method which calculate the first (prime) cost of a given transport task more precisely than the state of the art practices. In practice the calculation of transport fee depends on the individual estimation methods of the transport managers, which could result losses for the company.

In this study the elaborated calculation method for total first cost is detailed for three types of fulfilment of transport tasks. The most common type of achievement is, when “own vehicle is used with own driver”. A software was also developed for this case based on the elaborated method.

Based on the calculations of our software, the first cost can be defined quickly and precisely to realize higher profit.

Słowa kluczowe

  • road freight transport
  • first cost
  • calculation
  • profit maximization
  • software
Otwarty dostęp

Introducing the Methodology of Transplanting a New National Speed Management Strategy

Data publikacji: 26 Apr 2017
Zakres stron: 118 - 127

Abstrakt

Abstract

This paper explains the most important methodological steps of introducing a new speed management strategy. The development of a speed monitoring system with a long term effect on the progress of road safety, makes it necessary to identify its strategic goals, main functions and system components. The strategy should investigate current speed management methods, regulation framework of road signs, tendencies represented by statistics, enforcement campaigns, control equipment, and last but not least the penalty system. Assessment of the applied speed enforcement practices and framework should involve the revision of the recently operating institutional, legal and technical framework of speed enforcement structure.

Słowa kluczowe

  • speed management strategy
  • strategy adaptation
  • road safety
  • strategic element
Otwarty dostęp

Hierarchical Agglomerative Clustering Schemes for Energy-Efficiency in Wireless Sensor Networks

Data publikacji: 26 Apr 2017
Zakres stron: 128 - 138

Abstrakt

Abstract

Extending the lifetime of wireless sensor networks (WSNs) while delivering the expected level of service remains a hot research topic. Clustering has been identified in the literature as one of the primary means to save communication energy. In this paper, we argue that hierarchical agglomerative clustering (HAC) provides a suitable foundation for designing highly energy efficient communication protocols for WSNs. To this end, we study a new mechanism for selecting cluster heads (CHs) based both on the physical location of the sensors and their residual energy. Furthermore, we study different patterns of communications between the CHs and the base station depending on the possible transmission ranges and the ability of the sensors to act as traffic relays. Simulation results show that our proposed clustering and communication schemes outperform well-knows existing approaches by comfortable margins. In particular, networks lifetime is increased by more than 60% compared to LEACH and HEED, and by more than 30% compared to K-means clustering.

Słowa kluczowe

  • WSNs
  • hierarchical agglomerative clustering
  • cluster head
  • energy-efficiency
Otwarty dostęp

Models and Algorithms for Estimation and Minimization of the Risks Associated with Dredging

Data publikacji: 26 Apr 2017
Zakres stron: 139 - 145

Abstrakt

Abstract

There are a lot of models and algorithms to minimize risks during dredging operations and they are not without drawbacks. The paper describes the authors’ approach to solving this problem. Mathematical models are proposed and on their basis software is developed. Methods of the risk theory are used to minimize the risks. In this paper a consequence of influence refers to the deviation from the goal expressed in the expected results and the deviation of certain criterion factors. In this case, we mean any measure of quality. In its turn, risk factors reduce criterion factors. These factors are divided into categories - general transportation risks and risks of transporting ground. In these categories, one may derive the following risks - incidents at transport resulting from the impact of a set of random factors including the human one. For risk analysis and management, in addition to identifying critical chains of risk situations, the stochastic model for evaluating the chains is set forth. In order to implement this algorithm, the mathematical package Maple is used, which allows for conducting the required calculations with a software package including the Graph Theory. The paper presents fragments of the code listing.

Słowa kluczowe

  • dredging operations
  • risks assessment
  • risks minimization
Otwarty dostęp

GNSS Positioning Performance Analysis Using PSO-RBF Estimation Model

Data publikacji: 26 Apr 2017
Zakres stron: 146 - 154

Abstrakt

Abstract

Positioning solutions need to be more precise and available. The most frequent method used nowadays includes a GPS receiver, sometimes supported by other sensors. Generally, GPS and GNSS suffer from spreading perturbations that produce biases on pseudo-range measurements. With a view to optimize the use of the satellites received, we offer a positioning algorithm with pseudo range error modelling with the contribution of an appropriate filtering process. Extended Kalman Filter, The Rao- Blackwellized filter are among the most widely used algorithms to predict errors and to filter the high frequency noise. This paper describes a new method of estimating the pseudo-range errors based on the PSO-RBF model which achieves an optimal training criterion. This model is appropriate of its method to predict the GPS corrections for accurate positioning, it reduce the positioning errors at high velocities by more than 50% compared to the RLS or EKF methods.

Słowa kluczowe

  • GNSS
  • pseudo-range
  • filtering
  • prediction
  • PSO-RBF
Otwarty dostęp

Hierarchical Method of Inter-Area Fast Rerouting

Data publikacji: 26 Apr 2017
Zakres stron: 155 - 167

Abstrakt

Abstract

In this paper, in order to increase the scalability and fault-tolerance of routing solutions the hierarchical method of inter-area fast rerouting in communication networks was presented. The method is based on the decomposed representation of the flow-based routing model with the introduction of the area interaction conditions to ensure connectivity of the inter-area routes. The model includes conditions for border routers protection, adapted for both single path and multipath routing. During the research it was established that the efficiency of the proposed method in terms of the speed of the coordinating procedure convergence was most influenced by the number of border routers and the implemented routing strategy.

Słowa kluczowe

  • inter-area routing
  • hierarchy
  • fault-tolerance
  • fast rerouting

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