Transportation problem has many real world applications, it can be solved by linear programming model, but in most time the model exists more for less paradox, this paper considers the reasons for the paradox and s...Transportation problem has many real world applications, it can be solved by linear programming model, but in most time the model exists more for less paradox, this paper considers the reasons for the paradox and search the way to eliminate the phenomenon. First this paper formulates a loose constrained linear programming model for the transportation problem, and gives the definition of the paradox which exists in it, some preliminary notions and one example is also given. Then it gives a table based algorithm for the loose constrained model, the steps of the algorithm and example will follow. The examples show that: (1) It is not a contradictory that transportation problem exists more for less paradox. (2) The loose constrained model is better used in practice for its less total cost. (3) The algorithm is easy to calculate, to study and highly speed to convergence. Finally, comparied with other ways it shows that the loose constrained model can thoroughly eliminate the paradox.展开更多
Based on recent research developments in multi-objective solid transportation problem (MOSTP), this paper presents a fuzzy programming approach to determine the optimal compromise solution of MOSTP. The characteristic...Based on recent research developments in multi-objective solid transportation problem (MOSTP), this paper presents a fuzzy programming approach to determine the optimal compromise solution of MOSTP. The characteristic feature of the proposed approach is that various objectives are synthetically considered with marginal evaluation for individual objectives and global evaluation for all objectives. The decision-maker's preference is taken into account by his/her assigning weights to the objectives. With global evaluation for all objectives, a compromise programming model is formulated. As a generic aggregation operator is adopted, several solution methods proposed earlier become special cases of this approach, and the solution process also becomes more flexible and realistic. An illustrative numerical example is provided to demonstrate the approach.展开更多
In considering the vertical heat boundary approximation for the free surface applied. However, due to the existence of the transport problems in the upper ocean, the flat upper and the horizontal homogenous hypothesis...In considering the vertical heat boundary approximation for the free surface applied. However, due to the existence of the transport problems in the upper ocean, the flat upper and the horizontal homogenous hypothesis are usually wave motion, the application of this approximation may result in some errors to the solar irradiation since it decays quickly in respect to the actual thickness of the water layer below the surface; on the other hand, due to the fluctuation of the water layer depth, it is improper to neglect the effects of the horizontal advection and turbulent diffusion since they also contribute to the vertical heat transport. A new model is constructed in this study to reflect these effects. The corresponding numerical simulations show that the wave motion may remarkably accelerate the vertical heat transferring process and the variation of the temperature in the wave affected layer appears in an oscillating manner.展开更多
In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental co...In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation costs. Supply and transportation costs per unit of the quantities are also determined. The present study was carried out to evaluate the quality of gravel to know its suitability for aggregate (raw material for concrete and road). The samples of gravel were analyzed for petrographic, physical, mechanical and chemical properties. Samples were categorized as quartzite group and carbonate group according to ASTM standard 295. Among these, samples of quartzite group were found dominant. The petrography examination of gravels which was carried out constituted of opal, tridymite, chalcedony, crystobalite and alkali carbonates rocks. Those minerals react with alkalis in cement leading to expansion and cracking of concrete. Other components such as sulfides, sulfates, halites, iron oxides, clay minerals and anhydrites are examined, which might be present as coating and impurities. The present study indicated that all samples are suitable for concrete making and obtain the optimum solution for transporting these materials from quarries to cities with minimum cost according to Egyptian Code.展开更多
The objective of this paper is to illustrate behavioural aspects and a collaborative Delphi-based planning approach in the maritime transport chain. Therefore, this paper analyses changes in behavioural routines and g...The objective of this paper is to illustrate behavioural aspects and a collaborative Delphi-based planning approach in the maritime transport chain. Therefore, this paper analyses changes in behavioural routines and governance structures in the maritime transport chain using a case study that depicts mutual projections of expected container transhipment moderated by a neutral third for reducing the uncertainty in planning within the whole maritime transport chain. The actors＇ different views on container transport are collected and directly confronted to an expert panel showing bounded rationality and thus asymmetric information can be circumvented The planning approach shows how actors＇ different internal planning can be improved and evident to the market. The whole maritime transport chain expects the future development in container transport which can be given by using collaborative Delphi-based planning. As a result, an overall picture for planning issues can be constituted, improving both individual planning of the actors and expected market growth.展开更多
We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider ...We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call ＂transient osmosis＂. We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes.展开更多
Intracardic air embolism is uncommon, however it is a serious condition which frequently leads to catastrophic complications during or after invasive procedures resulting in significant morbidity and mortality. For a ...Intracardic air embolism is uncommon, however it is a serious condition which frequently leads to catastrophic complications during or after invasive procedures resulting in significant morbidity and mortality. For a successful re- suscitation of patients with intracardiac air embolism, hy- perbaric oxygen therapy is critical.~~2~ Still, due to a hyper- baric chamber＇s unavailability at many hospitals and con- cerns about patient movement resulting in further embolism during transport, such treatment method is gradually dimin- ishing.展开更多
The analysis of data and information available on developing countries clearly suggests that the current systems and trends of urban transportation, with respect to both mobility and safety, are not sustainable. The c...The analysis of data and information available on developing countries clearly suggests that the current systems and trends of urban transportation, with respect to both mobility and safety, are not sustainable. The cities of developing countries are typically characterized by high-density urban areas, absence of proper control on land use, lack of proper roads and parking facilities, poor public transport, lack of road user discipline etc. This results in the transportation problems, namely accident, congestion, and pollution, taking a very different and much severer shape in developing countries than those in cities of developed countries. Sustainable transport is also important for developing countries from the perspective of climate change, i.e., to improve carbon foot print/ecological foot print （E.F） etc. of transportation systems. From various researches, it has been established that worldwide the road transport has got a substantial share of carbon emissions （20-25% on an average）. This makes transportation an important sector for reducing carbon emissions and thus for addressing the climate change issue. These considerations therefore thrust the need for achieving sustainability in urban transport, particularly for developing countries, not just from mobility and safety perspective but also from the perspective of local and global environmental issues. This paper will critically analyze the above issues for developing countries and would suggest possible approaches to address both the transportation needs as well as climate change.展开更多
文摘Transportation problem has many real world applications, it can be solved by linear programming model, but in most time the model exists more for less paradox, this paper considers the reasons for the paradox and search the way to eliminate the phenomenon. First this paper formulates a loose constrained linear programming model for the transportation problem, and gives the definition of the paradox which exists in it, some preliminary notions and one example is also given. Then it gives a table based algorithm for the loose constrained model, the steps of the algorithm and example will follow. The examples show that: (1) It is not a contradictory that transportation problem exists more for less paradox. (2) The loose constrained model is better used in practice for its less total cost. (3) The algorithm is easy to calculate, to study and highly speed to convergence. Finally, comparied with other ways it shows that the loose constrained model can thoroughly eliminate the paradox.
文摘Based on recent research developments in multi-objective solid transportation problem (MOSTP), this paper presents a fuzzy programming approach to determine the optimal compromise solution of MOSTP. The characteristic feature of the proposed approach is that various objectives are synthetically considered with marginal evaluation for individual objectives and global evaluation for all objectives. The decision-maker's preference is taken into account by his/her assigning weights to the objectives. With global evaluation for all objectives, a compromise programming model is formulated. As a generic aggregation operator is adopted, several solution methods proposed earlier become special cases of this approach, and the solution process also becomes more flexible and realistic. An illustrative numerical example is provided to demonstrate the approach.
基金Supported by the National High Technology Research and Development Program of China (863 Program, No. 2006AA09A309)China Postdoctoral Science Foundation (No. 20070411111)the Fund of Shandong Province for the Excellent Post-Doctors (No. 200603056)
文摘In considering the vertical heat boundary approximation for the free surface applied. However, due to the existence of the transport problems in the upper ocean, the flat upper and the horizontal homogenous hypothesis are usually wave motion, the application of this approximation may result in some errors to the solar irradiation since it decays quickly in respect to the actual thickness of the water layer below the surface; on the other hand, due to the fluctuation of the water layer depth, it is improper to neglect the effects of the horizontal advection and turbulent diffusion since they also contribute to the vertical heat transport. A new model is constructed in this study to reflect these effects. The corresponding numerical simulations show that the wave motion may remarkably accelerate the vertical heat transferring process and the variation of the temperature in the wave affected layer appears in an oscillating manner.
文摘In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation costs. Supply and transportation costs per unit of the quantities are also determined. The present study was carried out to evaluate the quality of gravel to know its suitability for aggregate (raw material for concrete and road). The samples of gravel were analyzed for petrographic, physical, mechanical and chemical properties. Samples were categorized as quartzite group and carbonate group according to ASTM standard 295. Among these, samples of quartzite group were found dominant. The petrography examination of gravels which was carried out constituted of opal, tridymite, chalcedony, crystobalite and alkali carbonates rocks. Those minerals react with alkalis in cement leading to expansion and cracking of concrete. Other components such as sulfides, sulfates, halites, iron oxides, clay minerals and anhydrites are examined, which might be present as coating and impurities. The present study indicated that all samples are suitable for concrete making and obtain the optimum solution for transporting these materials from quarries to cities with minimum cost according to Egyptian Code.
文摘The objective of this paper is to illustrate behavioural aspects and a collaborative Delphi-based planning approach in the maritime transport chain. Therefore, this paper analyses changes in behavioural routines and governance structures in the maritime transport chain using a case study that depicts mutual projections of expected container transhipment moderated by a neutral third for reducing the uncertainty in planning within the whole maritime transport chain. The actors＇ different views on container transport are collected and directly confronted to an expert panel showing bounded rationality and thus asymmetric information can be circumvented The planning approach shows how actors＇ different internal planning can be improved and evident to the market. The whole maritime transport chain expects the future development in container transport which can be given by using collaborative Delphi-based planning. As a result, an overall picture for planning issues can be constituted, improving both individual planning of the actors and expected market growth.
文摘We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call ＂transient osmosis＂. We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes.
文摘Intracardic air embolism is uncommon, however it is a serious condition which frequently leads to catastrophic complications during or after invasive procedures resulting in significant morbidity and mortality. For a successful re- suscitation of patients with intracardiac air embolism, hy- perbaric oxygen therapy is critical.~~2~ Still, due to a hyper- baric chamber＇s unavailability at many hospitals and con- cerns about patient movement resulting in further embolism during transport, such treatment method is gradually dimin- ishing.
文摘The analysis of data and information available on developing countries clearly suggests that the current systems and trends of urban transportation, with respect to both mobility and safety, are not sustainable. The cities of developing countries are typically characterized by high-density urban areas, absence of proper control on land use, lack of proper roads and parking facilities, poor public transport, lack of road user discipline etc. This results in the transportation problems, namely accident, congestion, and pollution, taking a very different and much severer shape in developing countries than those in cities of developed countries. Sustainable transport is also important for developing countries from the perspective of climate change, i.e., to improve carbon foot print/ecological foot print （E.F） etc. of transportation systems. From various researches, it has been established that worldwide the road transport has got a substantial share of carbon emissions （20-25% on an average）. This makes transportation an important sector for reducing carbon emissions and thus for addressing the climate change issue. These considerations therefore thrust the need for achieving sustainability in urban transport, particularly for developing countries, not just from mobility and safety perspective but also from the perspective of local and global environmental issues. This paper will critically analyze the above issues for developing countries and would suggest possible approaches to address both the transportation needs as well as climate change.
