Pub Date : 2022-12-22DOI: 10.3846/transport.2022.18292
Xiongfei Zhou, L. Jing, Xiaoqi Ma
The wheel–rail interaction will be intensified on account of the complexity of the wheel–rail contact geometry on a curved track. It also may become more complicated and/or have significant difference as the train speed increases, since the dynamic effects cannot be ignored then. In this study, based on explicit Finite Element (FE) software LS-DYNA 971, a Three-Dimensional (3D) elastic-plastic FE model was built to simulate the dynamic wheel–rail contact behaviour of curve negotiating, where the superelevation and roll angle as well as the strain rate effect were considered. The evolution of contact patch and pressure, wheel–rail contact force, the stress/strain state and the acceleration of the axle were employed to examine the wheel–rail transient dynamic response. Furthermore, the influences of axle load, curve radius and strain rate effect were also discussed. It is found that the maximum vertical contact force, contact pressure, stress and strain on the curved track increase with the decreasing curve radius, and they increase with the increasing axle load except for lateral contact force. The wheel–rail dynamic responses on the curved track are significantly enhanced compared to the straight track. Moreover, the strain rate effect can enhance von-Mises stress and contact pressure, suppress the plastic deformation of the rail and wheel, but it has little effect on the vertical and lateral contact forces and stable acceleration of axle. The Rate-Sensitive Factors (RSF) of the wheel and rail on the curved track are weaker than those on the straight track. These findings will be very helpful to study the competitive relationship between the rolling contact fatigue and wear, as well as the crack initiation and propagation problem.
{"title":"DYNAMIC FINITE ELEMENT SIMULATION OF WHEEL–RAIL CONTACT RESPONSE FOR THE CURVED TRACK CASE","authors":"Xiongfei Zhou, L. Jing, Xiaoqi Ma","doi":"10.3846/transport.2022.18292","DOIUrl":"https://doi.org/10.3846/transport.2022.18292","url":null,"abstract":"The wheel–rail interaction will be intensified on account of the complexity of the wheel–rail contact geometry on a curved track. It also may become more complicated and/or have significant difference as the train speed increases, since the dynamic effects cannot be ignored then. In this study, based on explicit Finite Element (FE) software LS-DYNA 971, a Three-Dimensional (3D) elastic-plastic FE model was built to simulate the dynamic wheel–rail contact behaviour of curve negotiating, where the superelevation and roll angle as well as the strain rate effect were considered. The evolution of contact patch and pressure, wheel–rail contact force, the stress/strain state and the acceleration of the axle were employed to examine the wheel–rail transient dynamic response. Furthermore, the influences of axle load, curve radius and strain rate effect were also discussed. It is found that the maximum vertical contact force, contact pressure, stress and strain on the curved track increase with the decreasing curve radius, and they increase with the increasing axle load except for lateral contact force. The wheel–rail dynamic responses on the curved track are significantly enhanced compared to the straight track. Moreover, the strain rate effect can enhance von-Mises stress and contact pressure, suppress the plastic deformation of the rail and wheel, but it has little effect on the vertical and lateral contact forces and stable acceleration of axle. The Rate-Sensitive Factors (RSF) of the wheel and rail on the curved track are weaker than those on the straight track. These findings will be very helpful to study the competitive relationship between the rolling contact fatigue and wear, as well as the crack initiation and propagation problem.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87070656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.3846/transport.2022.17895
Haoyu Yuan, Jixin Wang, Shaofeng Du, Yunwu Han, Jindong Wang
To achieve energy-saving control of non-hybrid Hydrostatic Transmission Construction Vehicles (HST-CVs) with traditional closed-loop Hydrostatic Transmission (HST) for both propulsion and working systems, this paper presents a control strategy for non-hybrid HST-CVs by referring to the power follower method of the hybrid Energy Management Strategy (EMS). Through the implementation of the presented control strategy by coordinated control of the engine speed and hydraulic pump displacement, the engine can be controlled to operate at the pre-set low Brake Specific Fuel Consumption (BSFC) area, similar to that of the hybrid vehicles adopting a power follower control strategy but without the additional installation of accumulators in the hydraulic system. The effect of the control strategy is verified via experimental tests and MATLAB/SIMULINK–AMESIM COLlaborative SIMulation (COSIM). The simulation results show that the proposed control strategy can achieve the expected control target under both highway and off-road conditions.
{"title":"CONTROL STRATEGY FOR A NON-HYBRID HYDROSTATIC TRANSMISSION CONSTRUCTION VEHICLE BASED ON POWER FOLLOWER","authors":"Haoyu Yuan, Jixin Wang, Shaofeng Du, Yunwu Han, Jindong Wang","doi":"10.3846/transport.2022.17895","DOIUrl":"https://doi.org/10.3846/transport.2022.17895","url":null,"abstract":"To achieve energy-saving control of non-hybrid Hydrostatic Transmission Construction Vehicles (HST-CVs) with traditional closed-loop Hydrostatic Transmission (HST) for both propulsion and working systems, this paper presents a control strategy for non-hybrid HST-CVs by referring to the power follower method of the hybrid Energy Management Strategy (EMS). Through the implementation of the presented control strategy by coordinated control of the engine speed and hydraulic pump displacement, the engine can be controlled to operate at the pre-set low Brake Specific Fuel Consumption (BSFC) area, similar to that of the hybrid vehicles adopting a power follower control strategy but without the additional installation of accumulators in the hydraulic system. The effect of the control strategy is verified via experimental tests and MATLAB/SIMULINK–AMESIM COLlaborative SIMulation (COSIM). The simulation results show that the proposed control strategy can achieve the expected control target under both highway and off-road conditions.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"57 8 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86791143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-20DOI: 10.3846/transport.2022.17938
R. Ilves, Rauno Põldaru, A. Annuk, J. Olt
Nowadays, there is a global trend towards the use of alternative fuels in order to reduce environmental pollution. For example, Compressed Natural Gas (CNG) has become more widely used around the world. The use of different fuels in engines affects the combustion process and efficiency, with the latter potentially being reduced by such means as, for example, the use of gaseous fuels in conventional diesel engines. Therefore, it is also important to know how CNG combusts in a diesel engine and how the combustion process can be improved. Consequently, the aim of the study is to give an overview of the effect of divided Diesel Fuel (DF) pilot injection on the combustion process of a naturally aspirated diesel engine using dual-fuel mode, with one fuel being DF and the other CNG. The focus of the article is on the commonly used engines on which the diesel injection system works regularly, and CNG fuel is injected into the intake manifold as an additional fuel. The engine DF quantity and injection timing are regulated by the acceleration pedal. The article provides an overview of the diesel and dual-fuel combustion process, and compare the DF and dual-fuel combustion processes. For this purpose, a test was carried out in order to measure the various involved parameters, such as the combustion pressure, torque, and fuel consumption. The results demonstrated that ignition delay does not significantly vary with the use of gas as a fuel source, and the maximum combustion pressure is actually higher with gas. The combustion is more rapid in dual-fuel mode and results indicate that when using dual-fuel mode on regular engines, it would be necessary to regulate the pre- and main-injection timing.
{"title":"THE IMPACT OF A TWO-PHASE DIESEL FUEL PILOT INJECTION ON THE COMPRESSED NATURAL GAS AIR–FUEL MIXTURE COMBUSTION PROCESS IN A DIESEL ENGINE","authors":"R. Ilves, Rauno Põldaru, A. Annuk, J. Olt","doi":"10.3846/transport.2022.17938","DOIUrl":"https://doi.org/10.3846/transport.2022.17938","url":null,"abstract":"Nowadays, there is a global trend towards the use of alternative fuels in order to reduce environmental pollution. For example, Compressed Natural Gas (CNG) has become more widely used around the world. The use of different fuels in engines affects the combustion process and efficiency, with the latter potentially being reduced by such means as, for example, the use of gaseous fuels in conventional diesel engines. Therefore, it is also important to know how CNG combusts in a diesel engine and how the combustion process can be improved. Consequently, the aim of the study is to give an overview of the effect of divided Diesel Fuel (DF) pilot injection on the combustion process of a naturally aspirated diesel engine using dual-fuel mode, with one fuel being DF and the other CNG. The focus of the article is on the commonly used engines on which the diesel injection system works regularly, and CNG fuel is injected into the intake manifold as an additional fuel. The engine DF quantity and injection timing are regulated by the acceleration pedal. The article provides an overview of the diesel and dual-fuel combustion process, and compare the DF and dual-fuel combustion processes. For this purpose, a test was carried out in order to measure the various involved parameters, such as the combustion pressure, torque, and fuel consumption. The results demonstrated that ignition delay does not significantly vary with the use of gas as a fuel source, and the maximum combustion pressure is actually higher with gas. The combustion is more rapid in dual-fuel mode and results indicate that when using dual-fuel mode on regular engines, it would be necessary to regulate the pre- and main-injection timing.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"63 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88219534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-16DOI: 10.3846/transport.2022.18243
Željko Stević, Marko Subotić, I. Tanackov, S. Sremac, Bojana Ristić, S. Simic
The impact of geometric characteristics on traffic risk is reflected through identifying conflict points on roads,traffic accidents, and any other unforeseen situation that is inherently hazardous for traffic participants. In order to identify the road sections with the highest risk, it is necessary to consider a number of criteria that affect risk, and conduct extensive empirical research, analysis and data synthesis. This paper evaluates 9 sections of two-lane roads in the territory of Bosnia and Herzegovina (the Republic of Srpska) using an integrated Multi-Criteria Decision-Making (MCDM) model.To determine the significance of 8 criteria for the evaluation of the sections, it was applied a subjective–objective model consisting of 3 methods: (1) CRiteria Importance Through Inter-criteria Correlation (CRITIC), (2) FUll COnsistency Method (FUCOM) and (3) fuzzy PIvot Pairwise RElative Criteria Importance Assessment (PIPRECIA). The aggregation of the criterion values obtained using the methods yielded the final criterion values. Measurement Alternatives and Ranking according to COmpromise Solution (MARCOS) method was used to evaluate the sections and determine their objective diversity. The obtained results identified one location as extremely hazardous by most of analysed input parameters. The section with the highest risk is the Rudanka – Doboj section (A4), which represents a section of the road infrastructure of the 105 road. The validation of the results obtained by applying the integrated MCDM model was performed through an extensive sensitivity analysis. The weights of criteria were observed through initially individual methods implemented in the MARCOS method. Then, a comparative analysis was performed with 6 other MCDM methods and Spearman’s Correlation Coefficient (SCC) was calculated as a statistical indicator of rank correlation in a sensitivity analysis. In addition,the Standard Deviation (STDEV) of the obtained results was determined.
{"title":"EVALUATION OF TWO-LANE ROAD SECTIONS IN TERMS OF TRAFFIC RISK USING AN INTEGRATED MCDM MODEL","authors":"Željko Stević, Marko Subotić, I. Tanackov, S. Sremac, Bojana Ristić, S. Simic","doi":"10.3846/transport.2022.18243","DOIUrl":"https://doi.org/10.3846/transport.2022.18243","url":null,"abstract":"The impact of geometric characteristics on traffic risk is reflected through identifying conflict points on roads,traffic accidents, and any other unforeseen situation that is inherently hazardous for traffic participants. In order to identify the road sections with the highest risk, it is necessary to consider a number of criteria that affect risk, and conduct extensive empirical research, analysis and data synthesis. This paper evaluates 9 sections of two-lane roads in the territory of Bosnia and Herzegovina (the Republic of Srpska) using an integrated Multi-Criteria Decision-Making (MCDM) model.To determine the significance of 8 criteria for the evaluation of the sections, it was applied a subjective–objective model consisting of 3 methods: (1) CRiteria Importance Through Inter-criteria Correlation (CRITIC), (2) FUll COnsistency Method (FUCOM) and (3) fuzzy PIvot Pairwise RElative Criteria Importance Assessment (PIPRECIA). The aggregation of the criterion values obtained using the methods yielded the final criterion values. Measurement Alternatives and Ranking according to COmpromise Solution (MARCOS) method was used to evaluate the sections and determine their objective diversity. The obtained results identified one location as extremely hazardous by most of analysed input parameters. The section with the highest risk is the Rudanka – Doboj section (A4), which represents a section of the road infrastructure of the 105 road. The validation of the results obtained by applying the integrated MCDM model was performed through an extensive sensitivity analysis. The weights of criteria were observed through initially individual methods implemented in the MARCOS method. Then, a comparative analysis was performed with 6 other MCDM methods and Spearman’s Correlation Coefficient (SCC) was calculated as a statistical indicator of rank correlation in a sensitivity analysis. In addition,the Standard Deviation (STDEV) of the obtained results was determined.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"31 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88259194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-15DOI: 10.3846/transport.2022.17955
Longjian Wang, Yonggang Wang, Longfei Wang
Recognizing the stability of the traffic evolution process of urban traffic networks has been an important consideration in traffic evolution research. However, little work has been conducted on identifying and associating temporal Traffic State Pattern (TSP) with the traffic evolution process. By clustering multi-dimensional traffic time series, we attempted to map the traffic evolution process into massive transitions of consecutive TSPs. Through the statistics of the time distribution of the transitions, we then defined the stability coefficient to conduct a quantitative analysis of the traffic evolution process. An empirical study using 30 days of traffic flow rate data of multiple road sections from the network of Nanshan District (Shenzhen, China) was carried out. Numerical results indicated that the traffic evolution process experienced obvious nonlinear changes at different periods of the day, but presented a regular cycle characteristic from morning till night. Further, with consideration of different travel purposes and traffic features on weekday and weekend, more traffic dynamics was extracted, which would be conducive to understand the complex behaviour of traffic evolution process.
{"title":"STABILITY ANALYSIS FOR URBAN TRAFFIC EVOLUTION PROCESS USING TEMPORAL TRAFFIC STATE PATTERNS","authors":"Longjian Wang, Yonggang Wang, Longfei Wang","doi":"10.3846/transport.2022.17955","DOIUrl":"https://doi.org/10.3846/transport.2022.17955","url":null,"abstract":"Recognizing the stability of the traffic evolution process of urban traffic networks has been an important consideration in traffic evolution research. However, little work has been conducted on identifying and associating temporal Traffic State Pattern (TSP) with the traffic evolution process. By clustering multi-dimensional traffic time series, we attempted to map the traffic evolution process into massive transitions of consecutive TSPs. Through the statistics of the time distribution of the transitions, we then defined the stability coefficient to conduct a quantitative analysis of the traffic evolution process. An empirical study using 30 days of traffic flow rate data of multiple road sections from the network of Nanshan District (Shenzhen, China) was carried out. Numerical results indicated that the traffic evolution process experienced obvious nonlinear changes at different periods of the day, but presented a regular cycle characteristic from morning till night. Further, with consideration of different travel purposes and traffic features on weekday and weekend, more traffic dynamics was extracted, which would be conducive to understand the complex behaviour of traffic evolution process.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"203 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73374947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-29DOI: 10.3846/transport.2022.17067
Lei Wang, Qing Liu
Many previous cases have shown that port operations are susceptible to disruptive events. This paper proposes 2-stage Stochastic Programming (SP) for port users to reliably plan the hinterland-port intermodal freight network with consideration of risk aversion in cost. Probabilistic disruptions of intermodal terminals are considered as scenario-specific. In the 1st stage, intermodal paths are selected to obtain proper network capacities. In the 2nd stage, cargo flows are assigned for each disruption scenario on the planed network. The 2-stage model is firstly formulated in a risk-neutral environment to achieve the minimum expectation of total cost. Then, the Mean-Risk (MR) framework is adopted by incorporating a risk measure tool called Conditional Value-at-Risk (CVaR) into the expectation model, so as to reduce the cost of worst-case disruption scenarios. Benders’ Decomposition (BD) is introduced to efficiently solve the exponential many problem. Some numerical experiments are performed under different risk aversion parameters. With this study, network planners can decide network capacities with reasonable redundancies to improve the freight reliability in a cost-effective way. The proposed method provides a simple approach for the planners to quantify their risk appetites in cost and to impose them in the planning process, hence to trade-off the Expected Cost (EC) and the worst-case cost.
{"title":"RELIABLE PLANNING OF HINTERLAND-PORT FREIGHT NETWORK AGAINST TRANSFER DISRUPTION RISKS","authors":"Lei Wang, Qing Liu","doi":"10.3846/transport.2022.17067","DOIUrl":"https://doi.org/10.3846/transport.2022.17067","url":null,"abstract":"Many previous cases have shown that port operations are susceptible to disruptive events. This paper proposes 2-stage Stochastic Programming (SP) for port users to reliably plan the hinterland-port intermodal freight network with consideration of risk aversion in cost. Probabilistic disruptions of intermodal terminals are considered as scenario-specific. In the 1st stage, intermodal paths are selected to obtain proper network capacities. In the 2nd stage, cargo flows are assigned for each disruption scenario on the planed network. The 2-stage model is firstly formulated in a risk-neutral environment to achieve the minimum expectation of total cost. Then, the Mean-Risk (MR) framework is adopted by incorporating a risk measure tool called Conditional Value-at-Risk (CVaR) into the expectation model, so as to reduce the cost of worst-case disruption scenarios. Benders’ Decomposition (BD) is introduced to efficiently solve the exponential many problem. Some numerical experiments are performed under different risk aversion parameters. With this study, network planners can decide network capacities with reasonable redundancies to improve the freight reliability in a cost-effective way. The proposed method provides a simple approach for the planners to quantify their risk appetites in cost and to impose them in the planning process, hence to trade-off the Expected Cost (EC) and the worst-case cost.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"6 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81388599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-22DOI: 10.3846/transport.2022.17896
Chentong Bian, Guo-dong Yin, Liwei Xu, Ning Zhang
The main goal of this study is to propose a trajectory planning algorithm for the merging control of heterogeneous vehicular platoons. Merging control is essential for the application of vehicular platoons, by which vehicles can be coordinated to form a platoon in a lane. While most previous researches on merging control only considered the operation on straight roads and ramps. Few studies have investigated the merging operation on curve roads, which may hinder the application of platoons on general traffic environment. In this study, a trajectory planning algorithm is proposed for the merging control of heterogeneous vehicular platoons on curve roads with constant radius. The proposed algorithm consists of two stages for the operation of merging: the first stage is to align the vehicles in each lane to form a structure with a certain clearance; the second stage is to conduct a lane changing manoeuvre for each merging vehicle to form a platoon in a lane. In the proposed algorithm, the dynamic limits of speed and acceleration are considered. The distance of each vehicle can be guaranteed to avoid undesired collisions. Two simulations are carefully conducted for the merging control of heterogeneous vehicular platoons on a curve road to demonstrate the effectiveness of the proposed algorithm. The results of simulations indicate that the proposed algorithm is capable of the merging control of platoons on a curve road.
{"title":"TRAJECTORY PLANNING ALGORITHM FOR MERGING CONTROL OF HETEROGENEOUS VEHICULAR PLATOON ON CURVE ROAD","authors":"Chentong Bian, Guo-dong Yin, Liwei Xu, Ning Zhang","doi":"10.3846/transport.2022.17896","DOIUrl":"https://doi.org/10.3846/transport.2022.17896","url":null,"abstract":"The main goal of this study is to propose a trajectory planning algorithm for the merging control of heterogeneous vehicular platoons. Merging control is essential for the application of vehicular platoons, by which vehicles can be coordinated to form a platoon in a lane. While most previous researches on merging control only considered the operation on straight roads and ramps. Few studies have investigated the merging operation on curve roads, which may hinder the application of platoons on general traffic environment. In this study, a trajectory planning algorithm is proposed for the merging control of heterogeneous vehicular platoons on curve roads with constant radius. The proposed algorithm consists of two stages for the operation of merging: the first stage is to align the vehicles in each lane to form a structure with a certain clearance; the second stage is to conduct a lane changing manoeuvre for each merging vehicle to form a platoon in a lane. In the proposed algorithm, the dynamic limits of speed and acceleration are considered. The distance of each vehicle can be guaranteed to avoid undesired collisions. Two simulations are carefully conducted for the merging control of heterogeneous vehicular platoons on a curve road to demonstrate the effectiveness of the proposed algorithm. The results of simulations indicate that the proposed algorithm is capable of the merging control of platoons on a curve road.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"81 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82859668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-21DOI: 10.3846/transport.2022.17808
Rajko Ković, M. Milenković
This paper presents a simulation of the Project Portfolio Management (PPM) model usage in evaluation and selection of modernization projects of Serbian Railways. Performance review of the selected projects is conducted in regards to the strategic goals of the company, which have been established during the process of strategic planning. The project selection model is methodologically set up as a two-step selection model. The number of portfolio projects is narrowed down by ranking their importance in regards to the success of the modernization program (benefits, risks, and resources), which is followed by the ranking of the projects on the basis of their contribution to the realization of previously chosen liquidity and rentability goals, which are always a challenge when it comes to railway companies. This selection procedure is simulated by applying the Analytic Hierarchy Process (AHP), a mathematical model of linear programming, embedded in the software package “Expert Choice”. The simulation results show that, in this way, it is possible to achieve a considerable drop in the amount of necessary financial resources for the realization of modernization projects, which is also the main contribution of this paper. This proves the efficiency of the PPM concept application as a modern model of strategic management. The showcased model of project portfolio selection can find a significant usage among the current processes of railways restructuring, especially in financing of the projects of public–private partnerships.
{"title":"A TWO-STEP APPROACH FOR SELECTION OF RAILWAY MODERNIZATION PROJECTS BASED ON ANALYTIC HIERARCHY PROCESS","authors":"Rajko Ković, M. Milenković","doi":"10.3846/transport.2022.17808","DOIUrl":"https://doi.org/10.3846/transport.2022.17808","url":null,"abstract":"This paper presents a simulation of the Project Portfolio Management (PPM) model usage in evaluation and selection of modernization projects of Serbian Railways. Performance review of the selected projects is conducted in regards to the strategic goals of the company, which have been established during the process of strategic planning. The project selection model is methodologically set up as a two-step selection model. The number of portfolio projects is narrowed down by ranking their importance in regards to the success of the modernization program (benefits, risks, and resources), which is followed by the ranking of the projects on the basis of their contribution to the realization of previously chosen liquidity and rentability goals, which are always a challenge when it comes to railway companies. This selection procedure is simulated by applying the Analytic Hierarchy Process (AHP), a mathematical model of linear programming, embedded in the software package “Expert Choice”. The simulation results show that, in this way, it is possible to achieve a considerable drop in the amount of necessary financial resources for the realization of modernization projects, which is also the main contribution of this paper. This proves the efficiency of the PPM concept application as a modern model of strategic management. The showcased model of project portfolio selection can find a significant usage among the current processes of railways restructuring, especially in financing of the projects of public–private partnerships.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"32 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89179353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-18DOI: 10.3846/transport.2022.17783
Mustafa Hamurcu, T. Eren
The technological development of buses among the new alternative concepts is evaluated in this paper. Bus transportation is an important system in the public transportation, which is cheap, flexible and, in many cases, in terms of capacity and speed. But increasing car traffic in the city centre and increasing the emission such as Carbon Dioxide (CO2) in the air are some of the dangerous problems for urban life. Therefore, it is needed the public transportation to stop increasing car traffic and needed the cleaner technology for air and environmental quality. Electric Buses (EBs) can play an important role for resident’s life quality with improving the urban air quality. However, planners and managers have difficulty in decision-making due to diversified EBs together with the developing technology. Multi-criteria decision-making (MCDM) methods that are analytic decision processes, prepare a good solution for this problem. In this study, 5 EBs are assessed under the special criteria with Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Multi‐Objective Optimization on the basis of the Ratio Analysis (MOORA) methods. These 2 methods are MCDM methods that are used to aim of ranking of alternatives in the complex decision problem. These methods are applied to select the best EB under the 6 criteria. Finally, E5-Bus is selected as the best option that rank of the 1st at all the 3 methods. Besides, MOORA and TOPSIS methods were compared. The results are shown alongside the best bus selection for public transportation that MOORA method is also a strong tool for solving vehicle selection problems in transportation. The proposed model has been validated using existing real applications. The proposed multi-criteria analysis can be used for advising decision-makers in their decision-making process for Electric Vehicles (EVs) in the area of clean transportation.
本文对新概念客车的技术发展进行了评价。公共汽车运输是公共交通的一个重要系统，它便宜，灵活，在很多情况下，在容量和速度方面。但是，城市中心日益增加的汽车流量和空气中二氧化碳(CO2)等排放物的增加是城市生活面临的一些危险问题。因此，需要公共交通来停止增加的汽车交通，需要更清洁的空气和环境质量技术。随着城市空气质量的改善，电动公交车对居民的生活质量起到了重要的作用。然而，由于电子商务的多样化和技术的发展，规划者和管理者在决策时遇到了困难。多准则决策(MCDM)方法是一种分析决策过程，为这一问题提供了很好的解决方案。本研究采用TOPSIS (technical for Order of Preference by Similarity by Ideal Solution)和MOORA (Multi - Objective Optimization based of Ratio Analysis)方法对5个EBs进行了评价。这两种方法都是MCDM方法，用于对复杂决策问题中的备选方案进行排序。应用这些方法在6个标准下选择最佳EB。最后，选择E5-Bus作为3种方法中排名第一的最佳方案。并对MOORA法和TOPSIS法进行了比较。结果表明，在公共交通最佳公交选择的同时，MOORA方法也是解决交通运输车辆选择问题的有力工具。该模型已通过实际应用进行了验证。本文提出的多准则分析方法可为决策者在清洁交通领域的电动汽车决策过程中提供建议。
{"title":"APPLICATIONS OF THE MOORA AND TOPSIS METHODS FOR DECISION OF ELECTRIC VEHICLES IN PUBLIC TRANSPORTATION TECHNOLOGY","authors":"Mustafa Hamurcu, T. Eren","doi":"10.3846/transport.2022.17783","DOIUrl":"https://doi.org/10.3846/transport.2022.17783","url":null,"abstract":"The technological development of buses among the new alternative concepts is evaluated in this paper. Bus transportation is an important system in the public transportation, which is cheap, flexible and, in many cases, in terms of capacity and speed. But increasing car traffic in the city centre and increasing the emission such as Carbon Dioxide (CO2) in the air are some of the dangerous problems for urban life. Therefore, it is needed the public transportation to stop increasing car traffic and needed the cleaner technology for air and environmental quality. Electric Buses (EBs) can play an important role for resident’s life quality with improving the urban air quality. However, planners and managers have difficulty in decision-making due to diversified EBs together with the developing technology. Multi-criteria decision-making (MCDM) methods that are analytic decision processes, prepare a good solution for this problem. In this study, 5 EBs are assessed under the special criteria with Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Multi‐Objective Optimization on the basis of the Ratio Analysis (MOORA) methods. These 2 methods are MCDM methods that are used to aim of ranking of alternatives in the complex decision problem. These methods are applied to select the best EB under the 6 criteria. Finally, E5-Bus is selected as the best option that rank of the 1st at all the 3 methods. Besides, MOORA and TOPSIS methods were compared. The results are shown alongside the best bus selection for public transportation that MOORA method is also a strong tool for solving vehicle selection problems in transportation. The proposed model has been validated using existing real applications. The proposed multi-criteria analysis can be used for advising decision-makers in their decision-making process for Electric Vehicles (EVs) in the area of clean transportation.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"8 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85978931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-17DOI: 10.3846/transport.2022.18012
R. Ušpalytė-Vitkūnienė, G. Bureika, M. Burinskienė, Vaida Vabuolytė, Viktor Skrickij
Sharing mobility solutions changes people’s lives in cities; however, such services are not common in remote areas, where the most widespread transport mode is a privately owned car. The main challenge is that the existing transport system fails to meet the population’s daily travel needs in such regions. Sharing mobility covers environmental issues, infrastructure development, digitalisation, integration of different transport modes, and people behaviour changes. This study analyses the possibility of expanding the existing urban mobility sharing system in remote tourist areas of Lithuania; for this purpose, a small resort in the central part of Lithuania – Birštonas was selected, and a survey of residents and tourists (visitors) was conducted. Using the survey results of residents and tourists, the needs for Car Sharing (CS) and micro-mobility services are determined. The attitude of municipality, residents, tourists, service providers towards micro mobility and vehicle sharing services is determined. Based on the achieved results, further steps of service development are proposed. The article’s main aim is to evaluate the views of various stakeholders on the development of micro mobility and CS systems in remote areas and propose development solutions.
{"title":"SHARING MOBILITY SOLUTIONS IN REMOTE TOURISTIC AREA: CASE STUDY OF LITHUANIA","authors":"R. Ušpalytė-Vitkūnienė, G. Bureika, M. Burinskienė, Vaida Vabuolytė, Viktor Skrickij","doi":"10.3846/transport.2022.18012","DOIUrl":"https://doi.org/10.3846/transport.2022.18012","url":null,"abstract":"Sharing mobility solutions changes people’s lives in cities; however, such services are not common in remote areas, where the most widespread transport mode is a privately owned car. The main challenge is that the existing transport system fails to meet the population’s daily travel needs in such regions. Sharing mobility covers environmental issues, infrastructure development, digitalisation, integration of different transport modes, and people behaviour changes. This study analyses the possibility of expanding the existing urban mobility sharing system in remote tourist areas of Lithuania; for this purpose, a small resort in the central part of Lithuania – Birštonas was selected, and a survey of residents and tourists (visitors) was conducted. Using the survey results of residents and tourists, the needs for Car Sharing (CS) and micro-mobility services are determined. The attitude of municipality, residents, tourists, service providers towards micro mobility and vehicle sharing services is determined. Based on the achieved results, further steps of service development are proposed. The article’s main aim is to evaluate the views of various stakeholders on the development of micro mobility and CS systems in remote areas and propose development solutions.","PeriodicalId":23260,"journal":{"name":"Transport","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87118561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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