New renewable energy exploitation technologies in offshore structures are vital for future energy production systems.Offshore hybrid wind-wave power generation(HWWPG)systems face increased component failure rates beca...New renewable energy exploitation technologies in offshore structures are vital for future energy production systems.Offshore hybrid wind-wave power generation(HWWPG)systems face increased component failure rates because of harsh weather,significantly affecting the maintenance procedures and reliability.Different types of failure rates of the wind turbine(WT)and wave energy converter(WEC),e.g.,the degradation and failure rates during regular wind speed fluctuation,the degradation and failure rates during intense wind speed fluctuation are considered.By incorporating both WT and WEC,the HWWPG system is designed to enhance the overall amount of electrical energy produced by the system over a given period under varying weather conditions.The universal generating function technique is used to calculate the HWWPG system dependability measures in a structured and efficient manner.This research highlights that intense weather conditions increase the failure rates of both WT and WEC,resulting in higher maintenance costs and more frequent downtimes,thus impacting the HWWPG system’s reliability.Although the HWWPG system can meet the energy demands in the presence of high failure rates,the reliance of the hybrid system on both WT and WEC helps maintain a relatively stable demand satisfaction during periods of high energy demand despite adverse weather conditions.To confirm the added value and applicability of the developed model,a case study of an offshore hybrid platform is conducted.The findings underscore the system’s robustness in maintaining energy production under varied weather conditions,though higher failure rates and maintenance costs arise in intense scenarios.展开更多
The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas(SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, par...The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas(SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fuel blends with concentrations of aromatics similar to those found in marine fuel oils, i.e. 20%–30% by volume(%vol.), normal diesel oil(4%–5% vol. aromatics) is doped with a mixture of aromatics. Emission measurements are conducted in test-bed engine facilities and particle emissions over a wide size range are analyzed. Results show a decreased number of particles emitted(or not change) with an increase in the aromatic concentration in fuel. This is because there is a reduction in the cetane number of the fuel with an increased aromatic content, which effects the combustion process and results in decreased particle formation. However, when ignition improver is used to increase the cetane number, particle emissions remain at a lower level than for normal diesel oil; thereby emphasizing the presence of other factors in the formation of particles.展开更多
The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model ...The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model is tested by the data collected from the ports of Hong Kong and Kaohsiung. The results show that this model can be used to explain the transshipment competition relationship between the ports of Hong Kong and Kaohsiung well. A sensitivity analysis was also executed. The sensitivity analysis results showed that both the port of Hong Kong and Kaohsiung should decrease the charges of port and increase the effi- ciency of loading and discharging. Based on the sensitivity analysis results, some interesting conclusions and helpful suggestions were obtained for the managers of the ports of Hong Kong and Kaohsiung to improve their port management.展开更多
This paper describes the main activities of the ship recycling facilities that have moved to the Asia continent and puts emphasis on environmental and working conditions under the umbrella of the new IMO （Internation...This paper describes the main activities of the ship recycling facilities that have moved to the Asia continent and puts emphasis on environmental and working conditions under the umbrella of the new IMO （International Maritime Organization） convention. However, the convention is not enforced yet and the legal gaps found on limited existing regulations do not impose strict rules on the shipping industry and at the same time offer motives for the safe recycling of ships. Ship-owners seem reluctant to send their vessels for scrap but rather prefer to employ them till the last minute, preferably in areas where the environmentally-friendly concept is not of primary importance. The dynamics of this specialized industry can be better shown by examining variables such as legal instruments, occupational health and safety hazards, geographical allocation of scrapping sites, scrap prices, safety working plans and volume to be scrapped. The next step is to build a simulation model in order to discuss the relevant scenarios. The first scenario is based on the current conditions where the ship-owner＇s decision is mainly affected by the fluctuations of the market and whether the effectiveness of existing regulations can improve the working environment in terms of health and safety. The second scenario refers to the situation when the IMO Convention is implemented, then it will produce two major recycling markets, the first one for the convention ships and the second for non-convention ships.展开更多
Agriculture is a key facilitator of economic prosperity and nourishes the huge global population.To achieve sustainable agriculture,several factors should be considered,such as increasing nutrient and water efficiency...Agriculture is a key facilitator of economic prosperity and nourishes the huge global population.To achieve sustainable agriculture,several factors should be considered,such as increasing nutrient and water efficiency and/or improving soil health and quality.Using fertilizer is one of the fastest and easiest ways to improve the quality of nutrients inland and increase the effectiveness of crop yields.Fertilizer supplies most of the necessary nutrients for plants,and it is estimated that at least 30%-50%of crop yields is attributable to commercial fertilizer nutrient inputs.Fertilizer is always a major concern in achieving sustainable and efficient agriculture.Applying reasonable and customized fertilizerswill require a significant increase in the number of formulae,involving increasing costs and the accurate forecasting of the right time to apply the suitable formulae.An alternative solution is given by two-stage production planning under stochastic demand,which divides a planning schedule into two stages.The primary stage has non-existing demand information,the inputs of which are the proportion of raw materials needed for producing fertilizer products,the cost for purchasing materials,and the production cost.The total quantity of purchased material and produced products to be used in the blending process must be defined to meet as small as possible a paid cost.At the second stage,demand appears under multiple scenarios and their respective possibilities.This stage will provide a solution for each occurring scenario to achieve the best profit.The two-stage approach is presented in this paper,the mathematical model of which is based on linear integer programming.Considering the diversity of fertilizer types,themathematicalmodel can advise manufacturers about which products will generate as much as profit as possible.Specifically,two objectives are taken into account.First,the paper’s thesis focuses on minimizing overall system costs,e.g.,including inventory cost,purchasing cost,unit cost,and ordering cost at Stage 1.Second,the thesis pays attention tomaximizing total profit based on information from customer demand,as well as being informed regarding concerns about system cost at Stage 2.展开更多
With the continuous development of technology,traditional manual work has been becoming more and more automated.Most large or medium-sized companies have applied Enterprise Resource Planning(ERP)software into their bu...With the continuous development of technology,traditional manual work has been becoming more and more automated.Most large or medium-sized companies have applied Enterprise Resource Planning(ERP)software into their business and production activities.However,since many small firms cannot afford ERP because of its expensive cost,they often still employ manual work for the same tasks this software resolves,especially for scheduling.This paper aims to provide a possible solution for small businesses to try automated scheduling and discover whether it can help much.There are two main ways to make this determination:a mathematical model and a heuristic model,which are suitable for assessing low-and medium-sized workloads,respectively.This case study was carried out in a small domestic interior furniture company,particularly in scheduling for their customized products in two-stage flow shop.Normally,they produce according to the sequence of customers’orders.However,when we applied these supportive tools with batch-processing machines,they experienced enhanced production performance due to diminishing setup time for distinctive items and a more streamlined arrangement of job sequences.These changes were implemented for some small companies that do not use many production stages and have a suitable number of jobs and customers.If this method were applied to larger demands,it would need further improvement and development to become a complete tool that can perform like a part of an ERP system.展开更多
The shipbuilding industry in Europe is in crisis due to the recent economic recession and competition from countries with low labour costs. Greek shipyards have been forced to make a series of structural changes which...The shipbuilding industry in Europe is in crisis due to the recent economic recession and competition from countries with low labour costs. Greek shipyards have been forced to make a series of structural changes which have resulted in lower employment levels. Although these changes were gradually creating the conditions for shipyards profitably to re-enter international markets, the current economic crisis and the consequences to the shipping sector have created major problems to the shipyards employment. Perama shiprepair zone, an industrial zone mainly consisted from SMEs （small and medium enterprises） in shipbuilding and shiprepairing sector, has faced major problem for its survivability. In this article, a new approach is presented. Green offshore structures are expected to create competitive advantages in the zone and be a way to utilize available facilities and recover from the existing situation. International experience through case studies is presented followed by economic and technical feasibility for offshore windturbines construction and wave energy devices in shipyards. Finally, a general model shows that sustainable development is possible and shipyards have the adaptability and resources required tbr the production of renewable energy offshore structures.展开更多
The two main approaches that countries are using to ease the strain on healthcare infrastructure is building temporary hospitals that are specialized in treating COVID-19 patients and promoting preventive measures.As ...The two main approaches that countries are using to ease the strain on healthcare infrastructure is building temporary hospitals that are specialized in treating COVID-19 patients and promoting preventive measures.As such,the selection of the optimal location for a temporary hospital and the calculation of the prioritization of preventive measures are two of the most critical decisions during the pandemic,especially in densely populated areas where the risk of transmission of the virus is highest.If the location selection process or the prioritization of measures is poor,healthcare workers and patients can be harmed,and unnecessary costs may come into play.In this study,a decision support framework using a fuzzy analytic hierarchy process(FAHP)and a weighted aggregated sum product assessment model are proposed for selecting the location of a temporary hospital,and a FAHP model is proposed for calculating the prioritization of preventive measures against COVID-19.A case study is performed for Ho Chi Minh City using the proposed decision-making framework.The contribution of this work is to propose a multiple criteria decision-making model in a fuzzy environment for ranking potential locations for building temporary hospitals during the COVID-19 pandemic.The results of the study can be used to assist decisionmakers,such as government authorities and infectious disease experts,in dealing with the current pandemic as well as other diseases in the future.With the entire world facing the global pandemic of COVID-19,many scientists have applied research achievements in practice to help decision-makers make accurate decisions to prevent the pandemic.As the number of cases increases exponentially,it is crucial that government authorities and infectious disease experts make optimal decisions while considering multiple quantitative and qualitative criteria.As such,the proposed approach can also be applied to support complex decision-making processes in a fuzzy environment in different countries.展开更多
Suppliers play the vital role of ensuring the continuous supply of goods to themarket for businesses.If businesses do not maintain a strong bond with their suppliers,they may not be able to secure a steady supply of g...Suppliers play the vital role of ensuring the continuous supply of goods to themarket for businesses.If businesses do not maintain a strong bond with their suppliers,they may not be able to secure a steady supply of goods and products for their customers.As a result of failure to deliver products,the production and business activities of the business can be delayed which leads to the loss of customers.Normally,each trading enterprise will have a variety of commodity supply chains withmultiple suppliers.Suppliers play an important role and contribute to the value of the entire supply chain.Should any supplier encounters a problem,the whole supply chain of businesses will be affected and could lead to not guaranteeing the stable supply to the market.Thus,suppliers can be seen as a threat to businesses where they have the ability to increase input prices or decrease the quality of the required products and services they provide.The quantity of the business,and the supply lead time directly affect the operations and reduce the profitability of the business.The paper mainly focuses on the supplier selection problemunder a variety of price level and product families when using a two-phase fuzzy multi-objective linear programming.The objectives of the proposed model are to minimize the total purchasing and ordering cost in order to reduce the quantity of defective materials and the late-delivery components from suppliers.Moreover,the piecewise linear membership function is applied in themodel to determine an optimal solution which is based on the requirement of decision makers under their fuzzy environment.The results of this study can be applied in various business environment and provide a reliable decision tool for choosing potential suppliers relating to these objectives.Based on the results,the company canmake a good decision on supplier selection;therefore,the company can improve the quality and quantity of their final product.This is because,the best supplier can supply raw material using just-in-time application and reduce production risk on the manufacturing process.展开更多
Hedge has been proposed as an adaptive scheme, which guides the player’s hand in a multi-armed bandit full information game. Applications of this game exist in network path selection, load distribution, and network i...Hedge has been proposed as an adaptive scheme, which guides the player’s hand in a multi-armed bandit full information game. Applications of this game exist in network path selection, load distribution, and network interdiction. We perform a worst case analysis of the Hedge algorithm by using an adversary, who will consistently select penalties so as to maximize the player’s loss, assuming that the adversary’s penalty budget is limited. We further explore the performance of binary penalties, and we prove that the optimum binary strategy for the adversary is to make greedy decisions.展开更多
Maritime cluster is a well-established and productively researched theme by maritime policy and economics scholars. Maritime cluster＇s evolution is an under-investigated area, with ramifications in maritime policy an...Maritime cluster is a well-established and productively researched theme by maritime policy and economics scholars. Maritime cluster＇s evolution is an under-investigated area, with ramifications in maritime policy and business decision-making. In this paper, we study the evolutionary formation of maritime clusters, in the contemporary European blue economy context. We examine pertinent factors for the sustainable development of maritime clusters, with a strong technical, service and market innovation orientation. We merely examine the significance of legislative, financial, business networking and knowledge management related components. Qualitative empirical testing of the theoretical premises is performed for the Spanish, Italian, Greek and Cypriot cluster entities.展开更多
As flood extreme occurrences are projected to increase in intense and frequency due to climate change, the assessment of vulnerability and the identification of the most vulnerable areas, populations, assets and syste...As flood extreme occurrences are projected to increase in intense and frequency due to climate change, the assessment of vulnerability and the identification of the most vulnerable areas, populations, assets and systems are an urgent need. Vulnerability has been widely discussed and several flood projection tools have been developed using complex hydrological models. However, despite the significant contribution of flood projection maps to predicting the impact of potential floods, they are difficult and impractical to use by stakeholders and policy makers, while they have proven to be inefficient and out of date in several cases. This research aims to cover the gaps in coastal and riverine flood management, developing a method that models flood patterns, using geospatial data of past large flood disasters. The outcomes of this research produce a five scale vulnerability assessment method, which could be widely implemented in all sectors, including transport, critical infrastructure, public health, tourism, constructions etc. Moreover, they could facilitate decision making and provide a wide range of implementation by all stakeholders, insurance agents, land-use planners, risk experts and of course individual. According to this research, the majority of the elements exposed to flood hazards, lay at specific combinations between 1) elevation (Ei) and 2) distance from water-masses (Di), expressed as (Ei, Di), including: 1) in general landscapes: ([0 m, 1 m), [0 km, 6 km), [0 m - 3 m), [0 km, 3 km)) and ([0 m - 6 m), [0 km, 1 km)), 2) in low laying regions: ([0 m, 1 m), [0 km, 40 km), [0 m - 3 m), [0 km, 30 km)) and ([0 m - 6 m), [0 km, 15 km)) and 2) in riverine regions: ([0 m, 4 m), [0 km, 3 km)). All elements laying on these elevations and distances from water masses are considered extremely and highly vulnerable to flood extremes.展开更多
As a result of social awareness of air emission due to the use of fossil fuels, the utilization of the natural wind power resources becomes an important option to avoid the dependence on fossil resources in industrial...As a result of social awareness of air emission due to the use of fossil fuels, the utilization of the natural wind power resources becomes an important option to avoid the dependence on fossil resources in industrial activities. For example, the maritime industry, which is responsible for more than 90% of the world trade transport, has already started to look for solutions to use wind power as auxiliary propulsion for ships. The practical installation of the wind facilities often requires large amount of investment, while uncertainties for the corresponding energy gains are large. Therefore a reliable model to describe the variability of wind speeds is needed to estimate the expected available wind power, coefficient of the variation of the power and other statistics of interest, e.g. expected length of the wind conditions favorable for the wind-energy harvesting. In this paper, wind speeds are modeled by means of a spatio-temporal transformed Gaussian field. Its dependence structure is localized by introduction of time and space dependent parameters in the field. The model has the advantage of having a relatively small number of parameters. These parameters have natural physical interpretation and are statistically fitted to represent variability of observed wind speeds in ERA Interim reanalysis data set.展开更多
文摘New renewable energy exploitation technologies in offshore structures are vital for future energy production systems.Offshore hybrid wind-wave power generation(HWWPG)systems face increased component failure rates because of harsh weather,significantly affecting the maintenance procedures and reliability.Different types of failure rates of the wind turbine(WT)and wave energy converter(WEC),e.g.,the degradation and failure rates during regular wind speed fluctuation,the degradation and failure rates during intense wind speed fluctuation are considered.By incorporating both WT and WEC,the HWWPG system is designed to enhance the overall amount of electrical energy produced by the system over a given period under varying weather conditions.The universal generating function technique is used to calculate the HWWPG system dependability measures in a structured and efficient manner.This research highlights that intense weather conditions increase the failure rates of both WT and WEC,resulting in higher maintenance costs and more frequent downtimes,thus impacting the HWWPG system’s reliability.Although the HWWPG system can meet the energy demands in the presence of high failure rates,the reliance of the hybrid system on both WT and WEC helps maintain a relatively stable demand satisfaction during periods of high energy demand despite adverse weather conditions.To confirm the added value and applicability of the developed model,a case study of an offshore hybrid platform is conducted.The findings underscore the system’s robustness in maintaining energy production under varied weather conditions,though higher failure rates and maintenance costs arise in intense scenarios.
基金Angpanneföreningen’s Foundation for Research and Development(11-164)the Foundation for Swedish Environmental Research Institute(SIVL)Swedish Maritime Organization and Lighthouse for their financial support
文摘The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas(SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fuel blends with concentrations of aromatics similar to those found in marine fuel oils, i.e. 20%–30% by volume(%vol.), normal diesel oil(4%–5% vol. aromatics) is doped with a mixture of aromatics. Emission measurements are conducted in test-bed engine facilities and particle emissions over a wide size range are analyzed. Results show a decreased number of particles emitted(or not change) with an increase in the aromatic concentration in fuel. This is because there is a reduction in the cetane number of the fuel with an increased aromatic content, which effects the combustion process and results in decreased particle formation. However, when ignition improver is used to increase the cetane number, particle emissions remain at a lower level than for normal diesel oil; thereby emphasizing the presence of other factors in the formation of particles.
文摘The transshipment is an important issue in the current marine transportation. This paper constructed a mathematical programming model to elaborate the transshipment port selection for the shipping company. This model is tested by the data collected from the ports of Hong Kong and Kaohsiung. The results show that this model can be used to explain the transshipment competition relationship between the ports of Hong Kong and Kaohsiung well. A sensitivity analysis was also executed. The sensitivity analysis results showed that both the port of Hong Kong and Kaohsiung should decrease the charges of port and increase the effi- ciency of loading and discharging. Based on the sensitivity analysis results, some interesting conclusions and helpful suggestions were obtained for the managers of the ports of Hong Kong and Kaohsiung to improve their port management.
文摘This paper describes the main activities of the ship recycling facilities that have moved to the Asia continent and puts emphasis on environmental and working conditions under the umbrella of the new IMO （International Maritime Organization） convention. However, the convention is not enforced yet and the legal gaps found on limited existing regulations do not impose strict rules on the shipping industry and at the same time offer motives for the safe recycling of ships. Ship-owners seem reluctant to send their vessels for scrap but rather prefer to employ them till the last minute, preferably in areas where the environmentally-friendly concept is not of primary importance. The dynamics of this specialized industry can be better shown by examining variables such as legal instruments, occupational health and safety hazards, geographical allocation of scrapping sites, scrap prices, safety working plans and volume to be scrapped. The next step is to build a simulation model in order to discuss the relevant scenarios. The first scenario is based on the current conditions where the ship-owner＇s decision is mainly affected by the fluctuations of the market and whether the effectiveness of existing regulations can improve the working environment in terms of health and safety. The second scenario refers to the situation when the IMO Convention is implemented, then it will produce two major recycling markets, the first one for the convention ships and the second for non-convention ships.
文摘Agriculture is a key facilitator of economic prosperity and nourishes the huge global population.To achieve sustainable agriculture,several factors should be considered,such as increasing nutrient and water efficiency and/or improving soil health and quality.Using fertilizer is one of the fastest and easiest ways to improve the quality of nutrients inland and increase the effectiveness of crop yields.Fertilizer supplies most of the necessary nutrients for plants,and it is estimated that at least 30%-50%of crop yields is attributable to commercial fertilizer nutrient inputs.Fertilizer is always a major concern in achieving sustainable and efficient agriculture.Applying reasonable and customized fertilizerswill require a significant increase in the number of formulae,involving increasing costs and the accurate forecasting of the right time to apply the suitable formulae.An alternative solution is given by two-stage production planning under stochastic demand,which divides a planning schedule into two stages.The primary stage has non-existing demand information,the inputs of which are the proportion of raw materials needed for producing fertilizer products,the cost for purchasing materials,and the production cost.The total quantity of purchased material and produced products to be used in the blending process must be defined to meet as small as possible a paid cost.At the second stage,demand appears under multiple scenarios and their respective possibilities.This stage will provide a solution for each occurring scenario to achieve the best profit.The two-stage approach is presented in this paper,the mathematical model of which is based on linear integer programming.Considering the diversity of fertilizer types,themathematicalmodel can advise manufacturers about which products will generate as much as profit as possible.Specifically,two objectives are taken into account.First,the paper’s thesis focuses on minimizing overall system costs,e.g.,including inventory cost,purchasing cost,unit cost,and ordering cost at Stage 1.Second,the thesis pays attention tomaximizing total profit based on information from customer demand,as well as being informed regarding concerns about system cost at Stage 2.
文摘With the continuous development of technology,traditional manual work has been becoming more and more automated.Most large or medium-sized companies have applied Enterprise Resource Planning(ERP)software into their business and production activities.However,since many small firms cannot afford ERP because of its expensive cost,they often still employ manual work for the same tasks this software resolves,especially for scheduling.This paper aims to provide a possible solution for small businesses to try automated scheduling and discover whether it can help much.There are two main ways to make this determination:a mathematical model and a heuristic model,which are suitable for assessing low-and medium-sized workloads,respectively.This case study was carried out in a small domestic interior furniture company,particularly in scheduling for their customized products in two-stage flow shop.Normally,they produce according to the sequence of customers’orders.However,when we applied these supportive tools with batch-processing machines,they experienced enhanced production performance due to diminishing setup time for distinctive items and a more streamlined arrangement of job sequences.These changes were implemented for some small companies that do not use many production stages and have a suitable number of jobs and customers.If this method were applied to larger demands,it would need further improvement and development to become a complete tool that can perform like a part of an ERP system.
文摘The shipbuilding industry in Europe is in crisis due to the recent economic recession and competition from countries with low labour costs. Greek shipyards have been forced to make a series of structural changes which have resulted in lower employment levels. Although these changes were gradually creating the conditions for shipyards profitably to re-enter international markets, the current economic crisis and the consequences to the shipping sector have created major problems to the shipyards employment. Perama shiprepair zone, an industrial zone mainly consisted from SMEs （small and medium enterprises） in shipbuilding and shiprepairing sector, has faced major problem for its survivability. In this article, a new approach is presented. Green offshore structures are expected to create competitive advantages in the zone and be a way to utilize available facilities and recover from the existing situation. International experience through case studies is presented followed by economic and technical feasibility for offshore windturbines construction and wave energy devices in shipyards. Finally, a general model shows that sustainable development is possible and shipyards have the adaptability and resources required tbr the production of renewable energy offshore structures.
文摘The two main approaches that countries are using to ease the strain on healthcare infrastructure is building temporary hospitals that are specialized in treating COVID-19 patients and promoting preventive measures.As such,the selection of the optimal location for a temporary hospital and the calculation of the prioritization of preventive measures are two of the most critical decisions during the pandemic,especially in densely populated areas where the risk of transmission of the virus is highest.If the location selection process or the prioritization of measures is poor,healthcare workers and patients can be harmed,and unnecessary costs may come into play.In this study,a decision support framework using a fuzzy analytic hierarchy process(FAHP)and a weighted aggregated sum product assessment model are proposed for selecting the location of a temporary hospital,and a FAHP model is proposed for calculating the prioritization of preventive measures against COVID-19.A case study is performed for Ho Chi Minh City using the proposed decision-making framework.The contribution of this work is to propose a multiple criteria decision-making model in a fuzzy environment for ranking potential locations for building temporary hospitals during the COVID-19 pandemic.The results of the study can be used to assist decisionmakers,such as government authorities and infectious disease experts,in dealing with the current pandemic as well as other diseases in the future.With the entire world facing the global pandemic of COVID-19,many scientists have applied research achievements in practice to help decision-makers make accurate decisions to prevent the pandemic.As the number of cases increases exponentially,it is crucial that government authorities and infectious disease experts make optimal decisions while considering multiple quantitative and qualitative criteria.As such,the proposed approach can also be applied to support complex decision-making processes in a fuzzy environment in different countries.
文摘Suppliers play the vital role of ensuring the continuous supply of goods to themarket for businesses.If businesses do not maintain a strong bond with their suppliers,they may not be able to secure a steady supply of goods and products for their customers.As a result of failure to deliver products,the production and business activities of the business can be delayed which leads to the loss of customers.Normally,each trading enterprise will have a variety of commodity supply chains withmultiple suppliers.Suppliers play an important role and contribute to the value of the entire supply chain.Should any supplier encounters a problem,the whole supply chain of businesses will be affected and could lead to not guaranteeing the stable supply to the market.Thus,suppliers can be seen as a threat to businesses where they have the ability to increase input prices or decrease the quality of the required products and services they provide.The quantity of the business,and the supply lead time directly affect the operations and reduce the profitability of the business.The paper mainly focuses on the supplier selection problemunder a variety of price level and product families when using a two-phase fuzzy multi-objective linear programming.The objectives of the proposed model are to minimize the total purchasing and ordering cost in order to reduce the quantity of defective materials and the late-delivery components from suppliers.Moreover,the piecewise linear membership function is applied in themodel to determine an optimal solution which is based on the requirement of decision makers under their fuzzy environment.The results of this study can be applied in various business environment and provide a reliable decision tool for choosing potential suppliers relating to these objectives.Based on the results,the company canmake a good decision on supplier selection;therefore,the company can improve the quality and quantity of their final product.This is because,the best supplier can supply raw material using just-in-time application and reduce production risk on the manufacturing process.
文摘Hedge has been proposed as an adaptive scheme, which guides the player’s hand in a multi-armed bandit full information game. Applications of this game exist in network path selection, load distribution, and network interdiction. We perform a worst case analysis of the Hedge algorithm by using an adversary, who will consistently select penalties so as to maximize the player’s loss, assuming that the adversary’s penalty budget is limited. We further explore the performance of binary penalties, and we prove that the optimum binary strategy for the adversary is to make greedy decisions.
文摘Maritime cluster is a well-established and productively researched theme by maritime policy and economics scholars. Maritime cluster＇s evolution is an under-investigated area, with ramifications in maritime policy and business decision-making. In this paper, we study the evolutionary formation of maritime clusters, in the contemporary European blue economy context. We examine pertinent factors for the sustainable development of maritime clusters, with a strong technical, service and market innovation orientation. We merely examine the significance of legislative, financial, business networking and knowledge management related components. Qualitative empirical testing of the theoretical premises is performed for the Spanish, Italian, Greek and Cypriot cluster entities.
文摘As flood extreme occurrences are projected to increase in intense and frequency due to climate change, the assessment of vulnerability and the identification of the most vulnerable areas, populations, assets and systems are an urgent need. Vulnerability has been widely discussed and several flood projection tools have been developed using complex hydrological models. However, despite the significant contribution of flood projection maps to predicting the impact of potential floods, they are difficult and impractical to use by stakeholders and policy makers, while they have proven to be inefficient and out of date in several cases. This research aims to cover the gaps in coastal and riverine flood management, developing a method that models flood patterns, using geospatial data of past large flood disasters. The outcomes of this research produce a five scale vulnerability assessment method, which could be widely implemented in all sectors, including transport, critical infrastructure, public health, tourism, constructions etc. Moreover, they could facilitate decision making and provide a wide range of implementation by all stakeholders, insurance agents, land-use planners, risk experts and of course individual. According to this research, the majority of the elements exposed to flood hazards, lay at specific combinations between 1) elevation (Ei) and 2) distance from water-masses (Di), expressed as (Ei, Di), including: 1) in general landscapes: ([0 m, 1 m), [0 km, 6 km), [0 m - 3 m), [0 km, 3 km)) and ([0 m - 6 m), [0 km, 1 km)), 2) in low laying regions: ([0 m, 1 m), [0 km, 40 km), [0 m - 3 m), [0 km, 30 km)) and ([0 m - 6 m), [0 km, 15 km)) and 2) in riverine regions: ([0 m, 4 m), [0 km, 3 km)). All elements laying on these elevations and distances from water masses are considered extremely and highly vulnerable to flood extremes.
文摘As a result of social awareness of air emission due to the use of fossil fuels, the utilization of the natural wind power resources becomes an important option to avoid the dependence on fossil resources in industrial activities. For example, the maritime industry, which is responsible for more than 90% of the world trade transport, has already started to look for solutions to use wind power as auxiliary propulsion for ships. The practical installation of the wind facilities often requires large amount of investment, while uncertainties for the corresponding energy gains are large. Therefore a reliable model to describe the variability of wind speeds is needed to estimate the expected available wind power, coefficient of the variation of the power and other statistics of interest, e.g. expected length of the wind conditions favorable for the wind-energy harvesting. In this paper, wind speeds are modeled by means of a spatio-temporal transformed Gaussian field. Its dependence structure is localized by introduction of time and space dependent parameters in the field. The model has the advantage of having a relatively small number of parameters. These parameters have natural physical interpretation and are statistically fitted to represent variability of observed wind speeds in ERA Interim reanalysis data set.
