The lack of adequate and modern transport infrastructures makes the cost of transport in Africa higher than the rest of the world. Most of the transport infrastructures that exist were constructed during the colonial ...The lack of adequate and modern transport infrastructures makes the cost of transport in Africa higher than the rest of the world. Most of the transport infrastructures that exist were constructed during the colonial era which makes inter-regional connectivity difficult. The African Union in collaboration with other organization has committed to bridge the transport gap in Africa but still, face some challenges. This paper discusses the main issues that contribute for the weak nature of transportation in Sub-Saharan Africa with regards to the main transport modes and seeks to establish the possibility of sustainable intermodal transport through the integration of the different transport modes. Some policy reforms and other bilateral agreements such as deregulating the transport markets in West and Central Africa have been suggested to facilitate the development of an effective and efficient transport network in the Sub-Saharan African region.展开更多
This paper develops a model for analyzing the potential of longer and heavier vehicles (LHVs) related to pre- and post-haulage in the intermodal rail-road transport chain (IRT). The paper considers the combined econom...This paper develops a model for analyzing the potential of longer and heavier vehicles (LHVs) related to pre- and post-haulage in the intermodal rail-road transport chain (IRT). The paper considers the combined economic and emission costs among three different transport networks including intermodal rail-road transport with current Swedish regulatory framework for trucks, intermodal rail-road transport with LHVs, and direct-road transport. The objective is to analyse the potential of high-capacity transport associated with pre- and post-haulage for enhancing the competitiveness of intermodal transport from a full-costs perspective. The model developed is applied to a Swedish context and case study. Research findings reveal that the break-even of the IRT compared to the direct road transport could be significantly lowered, which suggests the LHVs contribute to exploring the market of IRT over smaller flows.展开更多
Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of...Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of passengers from the dominant mode to the connecting mode was achieved. A GI/M K/1 bulk service queuing system was constituted by putting the passengers' reaching time distribution as the input and the connecting mode as the service institution. Through queuing theory, the relationship between average queuing length under steady-state and headway of the connecting mode was achieved. By putting the minimum total cost of system as optimization objective, the headway as decision variable, a coordinated scheduling model of multimode in intermodal transit hubs was established. At last, a dynamic scheduling strategy was generated to cope with the unexpected changes of the dominant mode. The instance analysis indicates that this model can significantly reduce passengers' queuing time by approximately 17% with no apparently increase in departure frequency, which provides a useful solution for the coordinated scheduling of different transport modes in hubs.展开更多
In this paper, four potential cities to host an intermodal terminal for containers flowing through the Togolese transport corridor are examined. The transport cost minimization through the corridor is the main objecti...In this paper, four potential cities to host an intermodal terminal for containers flowing through the Togolese transport corridor are examined. The transport cost minimization through the corridor is the main objective. Consequently, the transport modes that offer the least cost to the transport supply chain are proposed. To attain this goal the paper aims to identify the optimal location for an intermodal terminal on the Togolese corridor, by using the mathematical linear programming model. For this, three transport scenarios are analyzed, the rail, the road, and the combination of these two transport modes to each of the landlocked countries (LLCs) capital cities of Burkina Faso, Mali and Niger. Data of the average transport cost per mode, the cargo demand of the LLCs, and the distances from origin to destinations are input in the LINGO software. Based on the optimization results, we find that among the preselected terminals, the city of Mango located at 550 km in the northern part of the country is the optimal host location for an intermodal terminal along the Togolese corridor. The results of this study may be helpful to transport policy makers in the quest of rendering better servicing to the landlocked countries.展开更多
This paper presents a Web-based Decision Support System (Web-DSS) that was designed and developed to support and provide suggestions on the procedures taking place between a port and a dry port, which have to collabor...This paper presents a Web-based Decision Support System (Web-DSS) that was designed and developed to support and provide suggestions on the procedures taking place between a port and a dry port, which have to collaborate, work concurrently and optimize their joint operation. The system operates at the highest hierarchical level supervising a number of different components dealing with three different time scale horizons so as to provide assistance at operational, tactical and strategic level. The Web-based DSS coordinates and integrates the subsystems operating at lower levels and it interfaces with all the involved actors: customers, suppliers, relevant authorities so as to receive all the necessary information to come up with “optimal” suggestions and decisions. In this paper, the overall architecture is presented and the individual modules are described.展开更多
The objective of this paper is to create a process view of the development of intermodal transport solution from the basic idea to implementation. Special case of dedicated solutions based on large shippers’ volumes ...The objective of this paper is to create a process view of the development of intermodal transport solution from the basic idea to implementation. Special case of dedicated solutions based on large shippers’ volumes is chosen, where the shippers engage in the development process of the new solutions. Research is conducted using a qualitative approach: multiple case studies. Empirical data has been obtained through in-depth semi-structured interviews with relevant respondents involved in the development projects. Shippers’ perspective on the development process is studied. Development process can be described through a generic four-stage process: Initiation, Planning, Implementation, and Further Development. Different actors and different resources are required at the different stages. The complex process of establishing new intermodal solutions has lacked attention in the intermodal research. Understanding and improving the development process of new intermodal solutions is considered to have an important effect on the viability of intermodal transport and can help to understand the barriers that prevent companies from switching to intermodal. Development process of new dedicated intermodal solutions is a gradual process of building up the transport solution in a continuous interaction between shippers and transport service providers. Research has focused on the shipper perspective on inter-modal transport, showing that switching to an intermodal transport is not simply a mode choice issue, but involves a transition process that takes time, demands resources, cooperation/coordination between multiple parties, may require changes in the supply chain beyond the transport link, involves multiple actors, and involves an industry that is itself in a process of change.展开更多
After the completion of Beijing New Airport, air-rail intermodality will become an important means of internal and external links in Jing-Jin-Ji Region. Jing-Jin-Ji Air-Rail Intermodality System is built and 7 sub-sys...After the completion of Beijing New Airport, air-rail intermodality will become an important means of internal and external links in Jing-Jin-Ji Region. Jing-Jin-Ji Air-Rail Intermodality System is built and 7 sub-systems are divided based on user demand analysis. Refer to the passenger process, the business process of the system is planned and the sub-systems are described using data flow diagram. The system provides theoretical support for the development of air-rail intermodal in Jing-Jin-Ji region.展开更多
Major problem considered in this study was the intermodal routing problem of regional freight transportation in West Africa ECOWAS (Economic Community Of West Africa States), which can be defined as the problem of det...Major problem considered in this study was the intermodal routing problem of regional freight transportation in West Africa ECOWAS (Economic Community Of West Africa States), which can be defined as the problem of determining the freight flow quantity, the transportation mode in each transit corridor while satisfying the freight demand at each West Africa transit country (Mali, Burkina Faso and Niger). The objective was to minimize in land transportation costs. In order to solve optimally and represent the problem, this research employed a linear programming model. The model was solved using Lingo Mathematic Application. The model results showed that port oriented freight logistics in west Africa ECOWAS region do not flow along optimal path and such incur longer time and higher logistics cost than is geographically necessary.展开更多
Since rail-road transport uses road and rail networks and requires the transshipment infrastructures at the terminals, its competitiveness depends not only on the costs but also on the location of these terminals. Thi...Since rail-road transport uses road and rail networks and requires the transshipment infrastructures at the terminals, its competitiveness depends not only on the costs but also on the location of these terminals. This paper focused on providing a methodology for determining the optimal locations for intermodal freight transportation terminals in consolidation network. The goal is to minimize total costs in order to increase the efficiency of the transportation system. This paper also has allowed us to have an overview of the methods and models that exist for solving the problem of intermodal and terminal locating.展开更多
Efficient and effective movement of goods is very critical in today’s competitive environment especially for developing countries suffering from crippling logistics costs which limit their competitive ability in the ...Efficient and effective movement of goods is very critical in today’s competitive environment especially for developing countries suffering from crippling logistics costs which limit their competitive ability in the global economy. Putting in place an optimal logistics network design offers great potential for logistics cost reduction and service quality improvement [1]. Therefore, this paper presents a model for effective integration of inland intermodal terminal into logistics network. The model simultaneously determines the number and location of inland terminals in network that minimize the total cost of freight flow to hinterland. The model uses Abidjan port in Cote d’Ivoire as the case study for solving numeric examples. The problem will be formulated in the case of a rail-road network where post-routing is done by road and rail link between terminal. We present a linear optimization model which is implemented using LINGO Mathematical Modeling Language.展开更多
Following September 11, 2001, numerous security policies have been created which have caused a number of unique challenges in planning for transportation networks. Transportation policy and funding to improve the tran...Following September 11, 2001, numerous security policies have been created which have caused a number of unique challenges in planning for transportation networks. Transportation policy and funding to improve the transportation infrastructure has historically been addressed as individual modes not as intermodal transportation. As a consequence of this inopportune allocation, it is now apparent that the transportation modes are disconnected and have unequal levels of security and efficiency. Improved intermodal connectivity has therefore been identified as one of the main challenges to achieve a safer, secure, and productive transportation network. Tools need to be refined for collaboration and consensus building to serve as catalysts for efficient transportation solutions. In this study, a mathematical model using data envelopment analysis (DEA) was developed and investigated to assess the safety and security of intermodal transportation facilities. The model identifies the best and worst performers by assessing several safety and security-related variables. The DEA model can assess the efficiency level of safety and security of intermodal facilities and identify potential solutions for improvement. The DEA methodology presented is general in its framework and can be applied to any network of intermodal transportation systems. Availability of credible data, complemented with DEA methodology will help in management decisions making concrete safety and security decisions for intermodal transportation facilities.展开更多
In the 1930s, when the competition among trucks and trains started, the Fascist government in Italy tried to implement a first form of road-rail integration. As a result, in this period, a transport intermodal network...In the 1930s, when the competition among trucks and trains started, the Fascist government in Italy tried to implement a first form of road-rail integration. As a result, in this period, a transport intermodal network existed for transport services for both freights and passengers. However, the network was quickly lost after the Second World War. The research objective of this paper regards the method of construction of a first form of intermodality (even before this term was used), through the analysis of theoretical texts and achievements of the era. The paper examines laws and regulations issued by the Fascist government. It shows how the willingness to implement a transport policy would lead to having coordinated transport. The success was not only political but also economic, as the coordinated transport may be cheaper and more effective.展开更多
Freight transportation in urban areas has increased significantly in a shorter period due to the widespread use of e-commerce, fast delivery, and population growth. Recently, a noticeable government initiative aimed a...Freight transportation in urban areas has increased significantly in a shorter period due to the widespread use of e-commerce, fast delivery, and population growth. Recently, a noticeable government initiative aimed at creating an effective, acceptable, and sustainable city logistics policy. This paper examines freight consolidation as a transportation strategy for optimizing last-mile delivery costs. Freight consolidation involves combining smaller shipments from various origins into a single, larger shipment for more efficient transportation to a common destination. This approach is particularly beneficial for last-mile delivery, where frequent deliveries of smaller quantities are frequently visible. Finally, we provide an illustrative example targeting urban freight stakeholders for practicing possible consolidation methodology. The result in the illustrative example shows that freight with 3-day consolidation, despite the delay penalty, is cheaper than daily shipping, and both are cheaper than 2-day consolidated shipping. The study will benefit urban businesses and freight services.展开更多
We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is ...We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method, which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results. Moreover, the system can omit the pre-calibration process by using the reference temperature before the temperature measurement. The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C, and the temperature uncertainty decreases from 16.8°C to 2.4°C. Moreover, the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber, which exhibits a distinctive improvement.展开更多
Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions...Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions,dispersion control becomes increasingly challenging as the bandwidth of the process of interest increases.Phase matching can also be achieved by exploiting the propagation characteristics of waves exciting different spatial modes of the same waveguide. Phase matching control in this case relies on achieving very similar propagation characteristics across two, and even more, waveguide modes over the wavelengths of interest, which may be rather far from one another. We demonstrate here that broadband(>40 nm) four-wave mixing can be achieved between pump waves and a signal located in different bands of the communications spectrum(separated by50 nm) by exploiting interband nonlinearities. Our demonstration is carried out in the silicon-rich silicon nitride material platform, which allows flexible device engineering, allowing for strong effective nonlinearity at telecommunications wavelengths without deleterious nonlinear-loss effects.展开更多
Containerized shipping is a growing market for agricultural exports,particularly soybeans.In order to understand the optimal strategies for improving the United States’economic competitiveness in this emerging market...Containerized shipping is a growing market for agricultural exports,particularly soybeans.In order to understand the optimal strategies for improving the United States’economic competitiveness in this emerging market,this research develops an intermodal transportation network modeling framework,focusing on U.S.soybean container shipments.Built upon detailed modal cost analyses,a Geospatial Intermodal Freight Transportation(GIFT)model has been developed to understand the optimal network design for U.S.soybean exports.Based on market demand and domestic supply figures,the model is able to determine which domestically produced soybeans should go to which foreign markets,and by which transport modes.This research and its continual studies,will provide insights into future policies and practices that can improve the transportation efficiency of soybean logistics.展开更多
This article explores from an intermodal perspective how visual and verbal historical documents contribute to the construction of value positions regarding the Mapuche people during colonial and early republican times...This article explores from an intermodal perspective how visual and verbal historical documents contribute to the construction of value positions regarding the Mapuche people during colonial and early republican times in the latest official 5 thgrade primary Chilean History textbook.The study analyzes,in particular,the visual and verbal historical secondary sources that build in combination evaluative prosodies that in turn contribute to construct determinate ideological perspectives regarding Mapuche people.The discourse analysis takes a social and ideological intermodal approach(Oteíza&Pinuer 2016,2019)focusing on an appraisal analysis(Martin&White 2005;Martin2014;Hood 2010;Oteíza&Pinuer 2012,2019)informed by socio-semiotic and Systemic Functional Linguistics theories.The cumulative intersemiotic reading of symbolic images and written documents privileges evaluative prosodies of negative integrity and of high conflict,in which Mapuche people are represented with more agency than Hispanics,emphasizing the stereotype of indigenous people as foreign,exotic and brave warriors,but also as violent,primitive and savage people that have had resisted Hispanic desires of slavering and cultural assimilation.Historical secondary sources offer alternative historical interpretations,although mainly constructed by evoked evaluations that could be less evident to children.展开更多
A tilt sensor based on an intermodal photonic crystal fiber (PCF) interferometer is demonstrated. The sensor consists of a tubular filled with NaC1 aqueous solutions and an intermodal PCF interferometer, which is fo...A tilt sensor based on an intermodal photonic crystal fiber (PCF) interferometer is demonstrated. The sensor consists of a tubular filled with NaC1 aqueous solutions and an intermodal PCF interferometer, which is formed by using a short PCF with two single-mode fibers (SMFs) spliced at both ends, and the air-holes in the splice regions are fully collapsed. The intermodal PCF interferometer is fixed in a rigid glass tubular with a slant orientation, and a half of the PCF is immersed in the NaC1 aqueous solutions, while the other half is exposed in air. When tilting the tubular, the length of the PCF immersed changes so that the transmission spectrum moves. Therefore, by monitoring the wavelength shift, the tilt angle can be achieved. In the experiment, a 0.8-cm-length intermodal PCF interferometer was adopted. The sensitivity of the proposed sensor was obtained from - 1.5461 nm/° to -30.1244 nm/° when measuring from -35.1 ° to 37.05°.展开更多
A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The pe...A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder(M-Z)and Sagnac interference model.In addition,the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding.The results show that the M-Z interference between LP_(01)and LP_(11)mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length,and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity.Due to the high birefringence of LP11 mode,the Sagnac interferometer has better RI sensing performance,the maximum RI sensing sensitivity of 12000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm,which is two orders of magnitude higher than the M-Z interferometer with the same fiber length.The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.展开更多
Overcoming the global sustainability challenges of logistics requires applying solutions that minimize the negative effects of logistics activities.The most efficient way of doing so is through intermodal transportati...Overcoming the global sustainability challenges of logistics requires applying solutions that minimize the negative effects of logistics activities.The most efficient way of doing so is through intermodal transportation(IT).Current IT systems rely mostly on road,rail,and sea transport,not inland waterway transport.Developing dry port(DP)terminals has been proven as a sustainable means of promoting and utilizing IT in the hinterland of seaport container terminals.Conventional DP systems consolidate container flows from/to seaports and integrate road and rail transportation modes in the hinterland which improves the sustainability of the whole logistics system.In this article,to extend literature on the sustainable development of different categories of IT terminals,especially DPs,and their varying roles,we examine the possibility of developing DP terminals within the framework of inland waterway container terminals(IWCTs).Establishing combined road–rail–inland waterway transport for observed container flows is expected to make the IT systems sustainable.As such,this article is the first to address the modelling of such DP systems.After mathematically formulating the problem of modelling DP systems,which entailed determining the number and location of DP terminals for IWCTs,their capacity,and their allocation of container flows,we solved the problem with a hybrid metaheuristic model based on the Bee Colony Optimisation(BCO)algorithmand themeasurement of alternatives and ranking according to compromise solution(i.e.,MARCOS)multi-criteria decision-making method.The results from our case study of the Danube region suggest that planning and developingDP terminals in the framework of IWCTs can indeed be sustainable,as well as contribute to the development of logistics networks,the regionalisation of river ports,and the geographic expansion of their hinterlands.Thus,the main contributions of this article are in proposing a novel DP concept variant,mathematically formulating the problems of its modelling,and developing an encompassing hybrid metaheuristic approach for treating the complex nature of the problem adequately.展开更多
文摘The lack of adequate and modern transport infrastructures makes the cost of transport in Africa higher than the rest of the world. Most of the transport infrastructures that exist were constructed during the colonial era which makes inter-regional connectivity difficult. The African Union in collaboration with other organization has committed to bridge the transport gap in Africa but still, face some challenges. This paper discusses the main issues that contribute for the weak nature of transportation in Sub-Saharan Africa with regards to the main transport modes and seeks to establish the possibility of sustainable intermodal transport through the integration of the different transport modes. Some policy reforms and other bilateral agreements such as deregulating the transport markets in West and Central Africa have been suggested to facilitate the development of an effective and efficient transport network in the Sub-Saharan African region.
文摘This paper develops a model for analyzing the potential of longer and heavier vehicles (LHVs) related to pre- and post-haulage in the intermodal rail-road transport chain (IRT). The paper considers the combined economic and emission costs among three different transport networks including intermodal rail-road transport with current Swedish regulatory framework for trucks, intermodal rail-road transport with LHVs, and direct-road transport. The objective is to analyse the potential of high-capacity transport associated with pre- and post-haulage for enhancing the competitiveness of intermodal transport from a full-costs perspective. The model developed is applied to a Swedish context and case study. Research findings reveal that the break-even of the IRT compared to the direct road transport could be significantly lowered, which suggests the LHVs contribute to exploring the market of IRT over smaller flows.
基金Projects(51278221,51378076)supported by the National Natural Science Foundation of China
文摘Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of passengers from the dominant mode to the connecting mode was achieved. A GI/M K/1 bulk service queuing system was constituted by putting the passengers' reaching time distribution as the input and the connecting mode as the service institution. Through queuing theory, the relationship between average queuing length under steady-state and headway of the connecting mode was achieved. By putting the minimum total cost of system as optimization objective, the headway as decision variable, a coordinated scheduling model of multimode in intermodal transit hubs was established. At last, a dynamic scheduling strategy was generated to cope with the unexpected changes of the dominant mode. The instance analysis indicates that this model can significantly reduce passengers' queuing time by approximately 17% with no apparently increase in departure frequency, which provides a useful solution for the coordinated scheduling of different transport modes in hubs.
文摘In this paper, four potential cities to host an intermodal terminal for containers flowing through the Togolese transport corridor are examined. The transport cost minimization through the corridor is the main objective. Consequently, the transport modes that offer the least cost to the transport supply chain are proposed. To attain this goal the paper aims to identify the optimal location for an intermodal terminal on the Togolese corridor, by using the mathematical linear programming model. For this, three transport scenarios are analyzed, the rail, the road, and the combination of these two transport modes to each of the landlocked countries (LLCs) capital cities of Burkina Faso, Mali and Niger. Data of the average transport cost per mode, the cargo demand of the LLCs, and the distances from origin to destinations are input in the LINGO software. Based on the optimization results, we find that among the preselected terminals, the city of Mango located at 550 km in the northern part of the country is the optimal host location for an intermodal terminal along the Togolese corridor. The results of this study may be helpful to transport policy makers in the quest of rendering better servicing to the landlocked countries.
文摘This paper presents a Web-based Decision Support System (Web-DSS) that was designed and developed to support and provide suggestions on the procedures taking place between a port and a dry port, which have to collaborate, work concurrently and optimize their joint operation. The system operates at the highest hierarchical level supervising a number of different components dealing with three different time scale horizons so as to provide assistance at operational, tactical and strategic level. The Web-based DSS coordinates and integrates the subsystems operating at lower levels and it interfaces with all the involved actors: customers, suppliers, relevant authorities so as to receive all the necessary information to come up with “optimal” suggestions and decisions. In this paper, the overall architecture is presented and the individual modules are described.
文摘The objective of this paper is to create a process view of the development of intermodal transport solution from the basic idea to implementation. Special case of dedicated solutions based on large shippers’ volumes is chosen, where the shippers engage in the development process of the new solutions. Research is conducted using a qualitative approach: multiple case studies. Empirical data has been obtained through in-depth semi-structured interviews with relevant respondents involved in the development projects. Shippers’ perspective on the development process is studied. Development process can be described through a generic four-stage process: Initiation, Planning, Implementation, and Further Development. Different actors and different resources are required at the different stages. The complex process of establishing new intermodal solutions has lacked attention in the intermodal research. Understanding and improving the development process of new intermodal solutions is considered to have an important effect on the viability of intermodal transport and can help to understand the barriers that prevent companies from switching to intermodal. Development process of new dedicated intermodal solutions is a gradual process of building up the transport solution in a continuous interaction between shippers and transport service providers. Research has focused on the shipper perspective on inter-modal transport, showing that switching to an intermodal transport is not simply a mode choice issue, but involves a transition process that takes time, demands resources, cooperation/coordination between multiple parties, may require changes in the supply chain beyond the transport link, involves multiple actors, and involves an industry that is itself in a process of change.
文摘After the completion of Beijing New Airport, air-rail intermodality will become an important means of internal and external links in Jing-Jin-Ji Region. Jing-Jin-Ji Air-Rail Intermodality System is built and 7 sub-systems are divided based on user demand analysis. Refer to the passenger process, the business process of the system is planned and the sub-systems are described using data flow diagram. The system provides theoretical support for the development of air-rail intermodal in Jing-Jin-Ji region.
文摘Major problem considered in this study was the intermodal routing problem of regional freight transportation in West Africa ECOWAS (Economic Community Of West Africa States), which can be defined as the problem of determining the freight flow quantity, the transportation mode in each transit corridor while satisfying the freight demand at each West Africa transit country (Mali, Burkina Faso and Niger). The objective was to minimize in land transportation costs. In order to solve optimally and represent the problem, this research employed a linear programming model. The model was solved using Lingo Mathematic Application. The model results showed that port oriented freight logistics in west Africa ECOWAS region do not flow along optimal path and such incur longer time and higher logistics cost than is geographically necessary.
文摘Since rail-road transport uses road and rail networks and requires the transshipment infrastructures at the terminals, its competitiveness depends not only on the costs but also on the location of these terminals. This paper focused on providing a methodology for determining the optimal locations for intermodal freight transportation terminals in consolidation network. The goal is to minimize total costs in order to increase the efficiency of the transportation system. This paper also has allowed us to have an overview of the methods and models that exist for solving the problem of intermodal and terminal locating.
文摘Efficient and effective movement of goods is very critical in today’s competitive environment especially for developing countries suffering from crippling logistics costs which limit their competitive ability in the global economy. Putting in place an optimal logistics network design offers great potential for logistics cost reduction and service quality improvement [1]. Therefore, this paper presents a model for effective integration of inland intermodal terminal into logistics network. The model simultaneously determines the number and location of inland terminals in network that minimize the total cost of freight flow to hinterland. The model uses Abidjan port in Cote d’Ivoire as the case study for solving numeric examples. The problem will be formulated in the case of a rail-road network where post-routing is done by road and rail link between terminal. We present a linear optimization model which is implemented using LINGO Mathematical Modeling Language.
文摘Following September 11, 2001, numerous security policies have been created which have caused a number of unique challenges in planning for transportation networks. Transportation policy and funding to improve the transportation infrastructure has historically been addressed as individual modes not as intermodal transportation. As a consequence of this inopportune allocation, it is now apparent that the transportation modes are disconnected and have unequal levels of security and efficiency. Improved intermodal connectivity has therefore been identified as one of the main challenges to achieve a safer, secure, and productive transportation network. Tools need to be refined for collaboration and consensus building to serve as catalysts for efficient transportation solutions. In this study, a mathematical model using data envelopment analysis (DEA) was developed and investigated to assess the safety and security of intermodal transportation facilities. The model identifies the best and worst performers by assessing several safety and security-related variables. The DEA model can assess the efficiency level of safety and security of intermodal facilities and identify potential solutions for improvement. The DEA methodology presented is general in its framework and can be applied to any network of intermodal transportation systems. Availability of credible data, complemented with DEA methodology will help in management decisions making concrete safety and security decisions for intermodal transportation facilities.
文摘In the 1930s, when the competition among trucks and trains started, the Fascist government in Italy tried to implement a first form of road-rail integration. As a result, in this period, a transport intermodal network existed for transport services for both freights and passengers. However, the network was quickly lost after the Second World War. The research objective of this paper regards the method of construction of a first form of intermodality (even before this term was used), through the analysis of theoretical texts and achievements of the era. The paper examines laws and regulations issued by the Fascist government. It shows how the willingness to implement a transport policy would lead to having coordinated transport. The success was not only political but also economic, as the coordinated transport may be cheaper and more effective.
文摘Freight transportation in urban areas has increased significantly in a shorter period due to the widespread use of e-commerce, fast delivery, and population growth. Recently, a noticeable government initiative aimed at creating an effective, acceptable, and sustainable city logistics policy. This paper examines freight consolidation as a transportation strategy for optimizing last-mile delivery costs. Freight consolidation involves combining smaller shipments from various origins into a single, larger shipment for more efficient transportation to a common destination. This approach is particularly beneficial for last-mile delivery, where frequent deliveries of smaller quantities are frequently visible. Finally, we provide an illustrative example targeting urban freight stakeholders for practicing possible consolidation methodology. The result in the illustrative example shows that freight with 3-day consolidation, despite the delay penalty, is cheaper than daily shipping, and both are cheaper than 2-day consolidated shipping. The study will benefit urban businesses and freight services.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 61527819 and 61875146)the Research Project by Shanxi Scholarship Council of China (Nos. 2016-036 and 2017-052)+2 种基金the Key Science and Technology Research Project Based on Coal of Shanxi Province (No. MQ2014-09)the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxithe Program for Sanjin Scholar
文摘We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS) for improving the temperature measurement accuracy and engineering applicability. The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method, which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results. Moreover, the system can omit the pre-calibration process by using the reference temperature before the temperature measurement. The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C, and the temperature uncertainty decreases from 16.8°C to 2.4°C. Moreover, the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber, which exhibits a distinctive improvement.
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/L00044X/1)
文摘Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions,dispersion control becomes increasingly challenging as the bandwidth of the process of interest increases.Phase matching can also be achieved by exploiting the propagation characteristics of waves exciting different spatial modes of the same waveguide. Phase matching control in this case relies on achieving very similar propagation characteristics across two, and even more, waveguide modes over the wavelengths of interest, which may be rather far from one another. We demonstrate here that broadband(>40 nm) four-wave mixing can be achieved between pump waves and a signal located in different bands of the communications spectrum(separated by50 nm) by exploiting interband nonlinearities. Our demonstration is carried out in the silicon-rich silicon nitride material platform, which allows flexible device engineering, allowing for strong effective nonlinearity at telecommunications wavelengths without deleterious nonlinear-loss effects.
基金The first author was funded by the Department of Civil and Environmental Engineering(CEE)at Rutgers UniversityThe second author was funded by the US Department of Agri-culture(15-TMXXX-NJ-0008)+1 种基金The third author was funded by National Natural Science Foundation of China(Grant No.51409157)Program of Humanities and Social Science of the Ministry of Education of China(14YJC630008).
文摘Containerized shipping is a growing market for agricultural exports,particularly soybeans.In order to understand the optimal strategies for improving the United States’economic competitiveness in this emerging market,this research develops an intermodal transportation network modeling framework,focusing on U.S.soybean container shipments.Built upon detailed modal cost analyses,a Geospatial Intermodal Freight Transportation(GIFT)model has been developed to understand the optimal network design for U.S.soybean exports.Based on market demand and domestic supply figures,the model is able to determine which domestically produced soybeans should go to which foreign markets,and by which transport modes.This research and its continual studies,will provide insights into future policies and practices that can improve the transportation efficiency of soybean logistics.
基金findings from research grant FONDECYT 1170331(National Funds for Science and Technology Development,Chile)
文摘This article explores from an intermodal perspective how visual and verbal historical documents contribute to the construction of value positions regarding the Mapuche people during colonial and early republican times in the latest official 5 thgrade primary Chilean History textbook.The study analyzes,in particular,the visual and verbal historical secondary sources that build in combination evaluative prosodies that in turn contribute to construct determinate ideological perspectives regarding Mapuche people.The discourse analysis takes a social and ideological intermodal approach(Oteíza&Pinuer 2016,2019)focusing on an appraisal analysis(Martin&White 2005;Martin2014;Hood 2010;Oteíza&Pinuer 2012,2019)informed by socio-semiotic and Systemic Functional Linguistics theories.The cumulative intersemiotic reading of symbolic images and written documents privileges evaluative prosodies of negative integrity and of high conflict,in which Mapuche people are represented with more agency than Hispanics,emphasizing the stereotype of indigenous people as foreign,exotic and brave warriors,but also as violent,primitive and savage people that have had resisted Hispanic desires of slavering and cultural assimilation.Historical secondary sources offer alternative historical interpretations,although mainly constructed by evoked evaluations that could be less evident to children.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 61108058, the National Basic Research Program of China (973 Program) under Grant No. 2010CB327804, the Zhejing Province Intemational Science and Technoloty Cooperation Special Programme under Grant No. 2013C24018, the National Key Technology R&D Program 2011BAF06B02 and the Science and Technology Commission of Shanghai Municipality of China under Grant No. 10595812300. Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, medium, provided the original credited. and reproduction in any author(s) and source are
文摘A tilt sensor based on an intermodal photonic crystal fiber (PCF) interferometer is demonstrated. The sensor consists of a tubular filled with NaC1 aqueous solutions and an intermodal PCF interferometer, which is formed by using a short PCF with two single-mode fibers (SMFs) spliced at both ends, and the air-holes in the splice regions are fully collapsed. The intermodal PCF interferometer is fixed in a rigid glass tubular with a slant orientation, and a half of the PCF is immersed in the NaC1 aqueous solutions, while the other half is exposed in air. When tilting the tubular, the length of the PCF immersed changes so that the transmission spectrum moves. Therefore, by monitoring the wavelength shift, the tilt angle can be achieved. In the experiment, a 0.8-cm-length intermodal PCF interferometer was adopted. The sensitivity of the proposed sensor was obtained from - 1.5461 nm/° to -30.1244 nm/° when measuring from -35.1 ° to 37.05°.
基金jointly supported by the Tianjin Natural Science Foundation(No.18JCQNJC71300)the National Natural Science Foundation of China(Nos.11804250,11904262 and 11704283)+1 种基金the Tianjin Education Commission Scientific Research Project(No.2018KJ146)the Opening Foundation of Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems(No.2019LODTS004)。
文摘A refractive index(RI)sensor based on elliptical core photonic crystal fiber(EC-PCF)has been proposed.The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes.The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder(M-Z)and Sagnac interference model.In addition,the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding.The results show that the M-Z interference between LP_(01)and LP_(11)mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length,and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity.Due to the high birefringence of LP11 mode,the Sagnac interferometer has better RI sensing performance,the maximum RI sensing sensitivity of 12000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm,which is two orders of magnitude higher than the M-Z interferometer with the same fiber length.The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.
文摘Overcoming the global sustainability challenges of logistics requires applying solutions that minimize the negative effects of logistics activities.The most efficient way of doing so is through intermodal transportation(IT).Current IT systems rely mostly on road,rail,and sea transport,not inland waterway transport.Developing dry port(DP)terminals has been proven as a sustainable means of promoting and utilizing IT in the hinterland of seaport container terminals.Conventional DP systems consolidate container flows from/to seaports and integrate road and rail transportation modes in the hinterland which improves the sustainability of the whole logistics system.In this article,to extend literature on the sustainable development of different categories of IT terminals,especially DPs,and their varying roles,we examine the possibility of developing DP terminals within the framework of inland waterway container terminals(IWCTs).Establishing combined road–rail–inland waterway transport for observed container flows is expected to make the IT systems sustainable.As such,this article is the first to address the modelling of such DP systems.After mathematically formulating the problem of modelling DP systems,which entailed determining the number and location of DP terminals for IWCTs,their capacity,and their allocation of container flows,we solved the problem with a hybrid metaheuristic model based on the Bee Colony Optimisation(BCO)algorithmand themeasurement of alternatives and ranking according to compromise solution(i.e.,MARCOS)multi-criteria decision-making method.The results from our case study of the Danube region suggest that planning and developingDP terminals in the framework of IWCTs can indeed be sustainable,as well as contribute to the development of logistics networks,the regionalisation of river ports,and the geographic expansion of their hinterlands.Thus,the main contributions of this article are in proposing a novel DP concept variant,mathematically formulating the problems of its modelling,and developing an encompassing hybrid metaheuristic approach for treating the complex nature of the problem adequately.