Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,...Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,and feedback loops arising out of the evolving nature of digitalization.This paper introduces a methodological framework to help address the intricate inter connections between digital applications and business models in the energy industry.The proposed framework leverages system dynamics to achieve two primary objectives.It investigates how digitalization generally influences the value proposi-tion,value capture,and value creation dimensions of business models.It also quantifies the financial and social impacts of digitalization from a dynamic perspective.The proposed dynamic CBA allows for a more precise quantification of the benefits and costs,associated with evidence-based decision-making.Findings from an illustrative case study challenge the static assumptions of conventional methods.These methods often presume continuous operation,neglecting reinvestment and operational feedback loops,and resulting in negative net present values.Conversely,the outcomes of the proposed method indicate positive net present values when accounting for factors such as reinvestment rates and the will-ingness to invest in digitalization projects.The principles outlined in this paper can enable a more accu-rate assessment of digitalization projects,thus catalyzing the development of new CBA applications and guidelines for digitalization.展开更多
Gestational Diabetes Mellitus (GDM) is a significant health concern affecting pregnant women worldwide. It is characterized by elevated blood sugar levels during pregnancy and poses risks to both maternal and fetal he...Gestational Diabetes Mellitus (GDM) is a significant health concern affecting pregnant women worldwide. It is characterized by elevated blood sugar levels during pregnancy and poses risks to both maternal and fetal health. Maternal complications of GDM include an increased risk of developing type 2 diabetes later in life, as well as hypertension and preeclampsia during pregnancy. Fetal complications may include macrosomia (large birth weight), birth injuries, and an increased risk of developing metabolic disorders later in life. Understanding the demographics, risk factors, and biomarkers associated with GDM is crucial for effective management and prevention strategies. This research aims to address these aspects comprehensively through the analysis of a dataset comprising 600 pregnant women. By exploring the demographics of the dataset and employing data modeling techniques, the study seeks to identify key risk factors associated with GDM. Moreover, by analyzing various biomarkers, the research aims to gain insights into the physiological mechanisms underlying GDM and its implications for maternal and fetal health. The significance of this research lies in its potential to inform clinical practice and public health policies related to GDM. By identifying demographic patterns and risk factors, healthcare providers can better tailor screening and intervention strategies for pregnant women at risk of GDM. Additionally, insights into biomarkers associated with GDM may contribute to the development of novel diagnostic tools and therapeutic approaches. Ultimately, by enhancing our understanding of GDM, this research aims to improve maternal and fetal outcomes and reduce the burden of this condition on healthcare systems and society. However, it’s important to acknowledge the limitations of the dataset used in this study. Further research utilizing larger and more diverse datasets, perhaps employing advanced data analysis techniques such as Power BI, is warranted to corroborate and expand upon the findings of this research. This underscores the ongoing need for continued investigation into GDM to refine our understanding and improve clinical management strategies.展开更多
Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing...Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail commuting.In this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained.For land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit stations.Meanwhile,employment and housing details of commuters around rail transit stations were identified using smart-card data.We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations.The distribution of building density and commuters in a mature rail line was roughly a normal distribution.However,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning systems.This study is the application of massive smart-card data in the field of urban research.It identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.展开更多
The electricity situation in Nigeria can be described as epileptic with no sign in view of improvement. This epileptic power situation affects the manufacturing, service and residential sectors of the economy which in...The electricity situation in Nigeria can be described as epileptic with no sign in view of improvement. This epileptic power situation affects the manufacturing, service and residential sectors of the economy which in turn affects the country’s economic growth. Even with the recent reforms in the power sector, more than half of the country’s population still lack access to electricity. The epileptic condition of the power sector can be attributed to the inadequate and inefficient power plants, poor transmission and distribution facilities, and outdated metering system used by electricity consumers. This paper attempts to present the way forward for the Nigerian poor electricity situation by reviewing the power sector as a whole and the renewable energy potentials. We identified the problems in the national grid and then proposed a smart grid model for the Nigerian power sector which will include renewable energy source. We believe that the content of this review paper will solve the poor epileptic condition of the power sector in Nigeria and also enable the proper integration of smart grid technology into the national grid.展开更多
We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpur...We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpurchase option as an outside option available to consumers. The demand for each choice is not only a function of the price but also the service quality, such as the total trip time, frequency of service, and ease of connecting from the hub to a nearby HSR station. As a result, the following findings are presented. First, regardless of the service quality of either sector and the non-purchase option,cooperation decreases the total volume of the domestic market of a country. Second, when the attractiveness of the outside option is high, the HSR and air sectors can prevent a large reduction in the total volume by cooperation in the connecting market. However, this is not the case in the domestic market. Third, if the non-purchase quality in the domestic market is high, then cooperation increases the social welfare of the whole market. If the non-purchase quality is low, then cooperation increases the welfare of the whole market only in cases where the number of potential customers in the connecting market is relatively large. We also show the effect of improving air–rail service quality on each market share and on the total profit.展开更多
This study presents a reliable model using Aspen Plus process simulator capable of performing a sensitivity analysis of the downdraft gasification linked to hydrogen production unit. Effects of key factors, including ...This study presents a reliable model using Aspen Plus process simulator capable of performing a sensitivity analysis of the downdraft gasification linked to hydrogen production unit. Effects of key factors, including gasification temperature and steam to biomass ratio (SBR) on the syngas composition, calorific value of syngas and hydrogen production are discussed and then the optimal conditions for maximum hydrogen production are extracted. The model is validated by experimental and other modeling data and found to be in great agreement. The sensitivity analysis results obtained by only using air as gasification agent indicate that higher temperatures are favorable for a product gas with higher hydrogen content and calorific value. Moreover, steam consumption as gasifying agent leads to increasing the hydrogen content and heating value of the syngas compared to the use of air as gasification agent. Finally, the results show that the optimal conditions to have the highest value of hydrogen output from sawdust downdraft gasification are 800˚C as gasifier temperature and 0.6 for SBR.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
Many types of cryptocurrencies,which predominantly utilize blockchain technology,have emerged worldwide.Several issuers plan to circulate their original cryptocurrencies for monetary use.This study investigates whethe...Many types of cryptocurrencies,which predominantly utilize blockchain technology,have emerged worldwide.Several issuers plan to circulate their original cryptocurrencies for monetary use.This study investigates whether issuers can stimulate cryptocurrencies to attain a monetary function.We use a multi-agent model,referred to as the Yasutomi model,which simulates the emergence of money.We analyze two scenarios that may result from the actions taken by the issuer.These scenarios focus on increases in the number of stores that accept cryptocurrency payments and situations whereby the cryptocurrency issuer designs the cryptocurrency to be attractive to people and conducts an airdrop.We find that a cryptocurrency can attain a monetary function in two cases.One such case occurs when 20%of all agents accept the cryptocurrency for payment and 50%of the agents are aware of this fact.The second case occurs when the issuer continuously airdrops a cryptocurrency to a specific person while maintaining the total volume of the cryptocurrency within a range that prevents it from losing its attractiveness.展开更多
Clean energy is vital for the sustainability of any economy in the world. Many industrialized nations have increased their production capacity of renewable energy while other countries lacking the technical expertise ...Clean energy is vital for the sustainability of any economy in the world. Many industrialized nations have increased their production capacity of renewable energy while other countries lacking the technical expertise and resource have resorted to import these technologies. The imported technologies mostly have standards that are followed by the manufactures while others are manufactured cheaply and exported to developing countries that do not have adequate standards and certification bodies. Nigeria which is a fast growing country has no existing standards to check the influx of renewable energy technologies into the country. This study stresses the need for the development of standards for renewable energy technologies in order to prevent the importation of substandard renewable energy technologies in Nigeria. The study reviews the renewable energy potentials in Nigeria, introduces the concept of standardization and discusses the development of standards for renewable energy technologies.展开更多
A qualitative and quantitative workplace assessment was carried out to determine naphtha exposure in a tyre manufacturing industry. A qualitative chemical health risk assessment was conducted to identify naphtha hazar...A qualitative and quantitative workplace assessment was carried out to determine naphtha exposure in a tyre manufacturing industry. A qualitative chemical health risk assessment was conducted to identify naphtha hazard at the workplace. Quantitative assessment using Portable VOC Monitor, Automatic Sampling Pump and personal air sampling pump was used to determine VOC concentrations, organic solvents, and individual air naphtha respectively. The risk rating of naphtha was estimated to be 5. The mean VOC concentration was in the range of 2.43 to 92.93 ppm. Repair area had the highest VOC concentration while the lowest was in the moulding area. Each work station had significant differences for VOC concentrations （p 〈 0.001）. Laboratory analysis found various solvents including 2-methyl pentane, hexane, methyl cyclopentane, heptane, cyclohexane and toluene which were present in the liquid naphtha. Only xylene has been detected in the making and moulding areas with a range of 2 to 5 ppm. Meanwhile, the air naphtha concentrations of the exposed workers were significantly higher than those unexposed. The risk of naphtha exposure was qualitatively significant and not adequately controlled. Naphtha was detected in all work stations since it is the main solvent used. The ＂Repair Area＂ was significantly more contaminated than the other area.展开更多
Differences in knowledge regimes and growth dynamics amongst four ideal types of knowledge based firms are analyzed. Two aspects of technological knowledge, technological opportunity and appropriability are traditiona...Differences in knowledge regimes and growth dynamics amongst four ideal types of knowledge based firms are analyzed. Two aspects of technological knowledge, technological opportunity and appropriability are traditionally seen as vital to understand the incentives for research and development activities in firms. However, they do not fully define the technology regimes, when one asks how the knowledge based firm competes. Therefore, the dynamic nature of firm capabilities and knowledge development in terms of expansion and in terms of deepening are also discussed. These two additional aspects of knowledge implies that even if all firms in an industry can be considered to be knowledge intensive these firms do also differ. Using cases of entrepreneurial start-up firms in Sweden, we illustrate whether our conceptual ideas of knowledge development help us understand the diversity and contradictions of firm evolution. Our finding is that firm evolution and capability development is dependent upon both the potential for expanding knowledge, such as by innovations, and by deepening the understanding within established knowledge, such as by learning. This implies that the shaping of a science based industry must be seen in relation both to the value of current knowledge and capabilities together with the sometimes only limited and temporarily advantages of radical innovations.展开更多
CO2 emission levels of copper and zinc mines from which Japanese smelters import ore concentrates into Japan,were estimated by using a database called MLED. Eleven copper mines selected from data availability of mine ...CO2 emission levels of copper and zinc mines from which Japanese smelters import ore concentrates into Japan,were estimated by using a database called MLED. Eleven copper mines selected from data availability of mine site covered 84% of the total imported concentrates. Adding inventories of sea transportation and smelting processes to mine development process,total CO2 emission level for copper and zinc ingots produced in Japan were calculated. The results show that the emission share of mining and mineral processing processes for each mine is indicated around 30%-70% of total emission for ingots,which implies the importance of including the mining activities to the inventory of upper stream products.展开更多
The quality of the drying process depends mainly on the efficient use of thermal energy.Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost.Howev...The quality of the drying process depends mainly on the efficient use of thermal energy.Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost.However,they are limited in use during off–sun periods.Biomass dryer is one of the simplest ways of drying because of its potential to dry products regardless of time and climate conditions.The other benefit is that crop residues could be used as fuel in these systems.However,the major limitation of the dryer is unequal drying because of poor airflow distribution in the drying medium,which can be improved by integrating some design changes in the dryer.This review analyses the two types of biomass dryers:industrial biomass dryers and small biomass dryers for food product,along with their efficiency.Further,studies on technical,sustainability and economic aspects are expected to provide a greater understanding of biomass drying.展开更多
1.Uncertainty in maritime transportation Maritime transportation plays a central role in global logistics systems.Over 80%of international trade is carried out via the maritime transportation network[1],which has rece...1.Uncertainty in maritime transportation Maritime transportation plays a central role in global logistics systems.Over 80%of international trade is carried out via the maritime transportation network[1],which has received widespread attention from academia and industry.In the shipping network,ports are the vertices where large numbers of activities occur,including cargo loading,unloading,and transshipment.Ships sailing between different ports travel along routes that form the links of the network.Shipping operation studies usually cover ship routing,schedule design,fleet deployment,and network design.展开更多
A crucial issue in collaborating in manufacturing corporate networks between different companies is to identify to what extent different strategic and operational decisions need to be coordinated between the involved ...A crucial issue in collaborating in manufacturing corporate networks between different companies is to identify to what extent different strategic and operational decisions need to be coordinated between the involved companies. In this paper, we elaborate on the issue of synchronization and coordination of information flow based on interconnectivities between companies in order to coordinate a corporate network by the means of DSM, Dependence Structure Matrix. The results show that DSM can be used to identify interconnectivities, dependencies on information flow among actors in a network and to identify which information needs to be shared between companies in the network.展开更多
In recent years,accidents and product recalls caused by product defects have become important problems in numerous industries worldwide.Nevertheless,most existing studies have examined product recalls using empirical ...In recent years,accidents and product recalls caused by product defects have become important problems in numerous industries worldwide.Nevertheless,most existing studies have examined product recalls using empirical approaches.To improve product recall systems,we studied social simulation using a multi-agent system with a co-evolution model.This research is important because empirical approaches are no longer adequate for complex and diverse modern societies.Discussions using quantitative and predictive approaches,including agent-based simulation,are therefore expected.For this study,we used a Layered Co-evolution Model to reflect situations of the real society using producer agents and consumer agents.Additionally,we applied multi-objective optimization techniques to introduce price competition situations into an artificial society.We conducted a simulation experiment,from which we discovered the possibilities that cost reduction for huge-scale product recalls is efficient,and that punishment of producers that conduct no product recalls can benefit consumers.We believe this work can contribute to supporting not only government staff for improving product recall systems,but also executive officers of product companies for deliberating their strategies of recall decisions.展开更多
The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly con...The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.展开更多
One promising means to reduce building energy for a more sustainable environment is to conduct early-stage building energy optimization using simulation,yet today’s simulation engines are computationally intensive.Re...One promising means to reduce building energy for a more sustainable environment is to conduct early-stage building energy optimization using simulation,yet today’s simulation engines are computationally intensive.Recently,machine learning(ML)energy prediction models have shown promise in replacing these simulation engines.However,it is often difficult to develop such ML models due to the lack of proper datasets.Synthetic datasets can provide a solution,but determining the optimal quantity and diversity of synthetic data remains a challenging task.Furthermore,there is a lack of understanding of the compatibility between different ML algorithms and the characteristics of synthetic datasets.To fill these gaps,this study conducted multiple ML experiments using residential buildings in Sweden to determine the best-performing ML algorithm,as well as the characteristics of the corresponding synthetic dataset.A parametric model was developed to generate a wide range of synthetic datasets varying in size and building shape,referred to as diversity.Five ML algorithms selected through a literature review were trained using the different datasets.Results show that the Support Vector Machine performed the best overall.Multiple Linear Regression performed well with small and lowdiverse datasets,while the Artificial Neural Network performed well with large and high-diverse datasets.We conclude that developers should focus more on increasing diversity instead of size once the dataset size reaches around 1440 when generating synthetic training datasets.This study offers insights for researchers and practitioners,such as software tool developers,when developing ML building energy prediction models in early-stage optimization.展开更多
In naval direct current(DC)microgrids,pulsed power loads(PPLs)are becoming more prominent.A solar sys-tem,an energy storage system,and a pulse load coupled directly to the DC bus compose a DC microgrid in this study.F...In naval direct current(DC)microgrids,pulsed power loads(PPLs)are becoming more prominent.A solar sys-tem,an energy storage system,and a pulse load coupled directly to the DC bus compose a DC microgrid in this study.For DC mi-crogrids equipped with sonar,radar,and other sensors,pulse load research is crucial.Due to high pulse loads,there is a possibility of severe power pulsation and voltage loss.The original contribution of this paper is that we are able to address the nonlinear problem by applying the Takagi-Sugeno(TS)model formulation for naval DC microgrids.Additionally,we provide a nonlinear power observer for estimating major disturbances affecting DC microgrids.To demonstrate the TS-potential,we examine three approaches for mitigating their negative effects:instantaneous power control(IPC)control,model predictive control(MPC)formulation,and TS-MPC approach with compensated PPLs.The results reveal that the TS-MPC approach with adjusted PPLs effectively shares power and regulates bus voltage under a variety of load conditions,while greatly decreasing detrimental impacts of the pulse load.Additionally,the comparison confirmed the efficiency of this technique.Index Terms-DC microgrids(MG),model predictive control(MPC),pulsed power loads(PPLs),nonlinear power observer,Takagi-Sugeno(TS)fuzzy model.展开更多
The 76th session of the Marine Environment Committee(MEPC 76)of the International Maritime Organization adopted several mandatory measures in June 2021 to reduce carbon emissions from ships.One of the measures is the ...The 76th session of the Marine Environment Committee(MEPC 76)of the International Maritime Organization adopted several mandatory measures in June 2021 to reduce carbon emissions from ships.One of the measures is the carbon intensity indicator(CII),which is the carbon emissions per unit transport work for each ship.Several options of CIIs are available and none of them is chosen to be applied yet.We prove that,at least in theory,requiring the attained annual CII of a ship to be less than a reference value,no matter which CII option is applied,may increase its carbon emissions.Therefore,more elaborate models,combined with real data,should be developed to analyze the effectiveness of each CII option and possibly to design a new CII.展开更多
基金conducted as part of the project Innovative Tools for Cyber-Physical Energy Systems(InnoCyPES)received funding from the European Union’s Horizon 2020 research and innovation pro-gram under the Marie Skłodowska-Curie(956433).
文摘Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,and feedback loops arising out of the evolving nature of digitalization.This paper introduces a methodological framework to help address the intricate inter connections between digital applications and business models in the energy industry.The proposed framework leverages system dynamics to achieve two primary objectives.It investigates how digitalization generally influences the value proposi-tion,value capture,and value creation dimensions of business models.It also quantifies the financial and social impacts of digitalization from a dynamic perspective.The proposed dynamic CBA allows for a more precise quantification of the benefits and costs,associated with evidence-based decision-making.Findings from an illustrative case study challenge the static assumptions of conventional methods.These methods often presume continuous operation,neglecting reinvestment and operational feedback loops,and resulting in negative net present values.Conversely,the outcomes of the proposed method indicate positive net present values when accounting for factors such as reinvestment rates and the will-ingness to invest in digitalization projects.The principles outlined in this paper can enable a more accu-rate assessment of digitalization projects,thus catalyzing the development of new CBA applications and guidelines for digitalization.
文摘Gestational Diabetes Mellitus (GDM) is a significant health concern affecting pregnant women worldwide. It is characterized by elevated blood sugar levels during pregnancy and poses risks to both maternal and fetal health. Maternal complications of GDM include an increased risk of developing type 2 diabetes later in life, as well as hypertension and preeclampsia during pregnancy. Fetal complications may include macrosomia (large birth weight), birth injuries, and an increased risk of developing metabolic disorders later in life. Understanding the demographics, risk factors, and biomarkers associated with GDM is crucial for effective management and prevention strategies. This research aims to address these aspects comprehensively through the analysis of a dataset comprising 600 pregnant women. By exploring the demographics of the dataset and employing data modeling techniques, the study seeks to identify key risk factors associated with GDM. Moreover, by analyzing various biomarkers, the research aims to gain insights into the physiological mechanisms underlying GDM and its implications for maternal and fetal health. The significance of this research lies in its potential to inform clinical practice and public health policies related to GDM. By identifying demographic patterns and risk factors, healthcare providers can better tailor screening and intervention strategies for pregnant women at risk of GDM. Additionally, insights into biomarkers associated with GDM may contribute to the development of novel diagnostic tools and therapeutic approaches. Ultimately, by enhancing our understanding of GDM, this research aims to improve maternal and fetal outcomes and reduce the burden of this condition on healthcare systems and society. However, it’s important to acknowledge the limitations of the dataset used in this study. Further research utilizing larger and more diverse datasets, perhaps employing advanced data analysis techniques such as Power BI, is warranted to corroborate and expand upon the findings of this research. This underscores the ongoing need for continued investigation into GDM to refine our understanding and improve clinical management strategies.
基金supported by the Innovative Post of Post-doctor in Hubei Province,China[grant number 2018(641)]National Natural Science Foundation of China[grant number 52078389]。
文摘Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail commuting.In this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained.For land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit stations.Meanwhile,employment and housing details of commuters around rail transit stations were identified using smart-card data.We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations.The distribution of building density and commuters in a mature rail line was roughly a normal distribution.However,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning systems.This study is the application of massive smart-card data in the field of urban research.It identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.
文摘The electricity situation in Nigeria can be described as epileptic with no sign in view of improvement. This epileptic power situation affects the manufacturing, service and residential sectors of the economy which in turn affects the country’s economic growth. Even with the recent reforms in the power sector, more than half of the country’s population still lack access to electricity. The epileptic condition of the power sector can be attributed to the inadequate and inefficient power plants, poor transmission and distribution facilities, and outdated metering system used by electricity consumers. This paper attempts to present the way forward for the Nigerian poor electricity situation by reviewing the power sector as a whole and the renewable energy potentials. We identified the problems in the national grid and then proposed a smart grid model for the Nigerian power sector which will include renewable energy source. We believe that the content of this review paper will solve the poor epileptic condition of the power sector in Nigeria and also enable the proper integration of smart grid technology into the national grid.
基金funding support from a JSPS Grant-in-Aid for Young Scientists (B) (26870643)funding support from a JSPS fellowship in 2013–2014 during his sabbatical at the National Graduate Institute for Policy Studies,Japan
文摘We study cooperation between the airline and high-speed rail(HSR) sectors by formulating their joint profit as a maximization problem using a multinomial logit choice model in a three-node setting. We allow the nonpurchase option as an outside option available to consumers. The demand for each choice is not only a function of the price but also the service quality, such as the total trip time, frequency of service, and ease of connecting from the hub to a nearby HSR station. As a result, the following findings are presented. First, regardless of the service quality of either sector and the non-purchase option,cooperation decreases the total volume of the domestic market of a country. Second, when the attractiveness of the outside option is high, the HSR and air sectors can prevent a large reduction in the total volume by cooperation in the connecting market. However, this is not the case in the domestic market. Third, if the non-purchase quality in the domestic market is high, then cooperation increases the social welfare of the whole market. If the non-purchase quality is low, then cooperation increases the welfare of the whole market only in cases where the number of potential customers in the connecting market is relatively large. We also show the effect of improving air–rail service quality on each market share and on the total profit.
文摘This study presents a reliable model using Aspen Plus process simulator capable of performing a sensitivity analysis of the downdraft gasification linked to hydrogen production unit. Effects of key factors, including gasification temperature and steam to biomass ratio (SBR) on the syngas composition, calorific value of syngas and hydrogen production are discussed and then the optimal conditions for maximum hydrogen production are extracted. The model is validated by experimental and other modeling data and found to be in great agreement. The sensitivity analysis results obtained by only using air as gasification agent indicate that higher temperatures are favorable for a product gas with higher hydrogen content and calorific value. Moreover, steam consumption as gasifying agent leads to increasing the hydrogen content and heating value of the syngas compared to the use of air as gasification agent. Finally, the results show that the optimal conditions to have the highest value of hydrogen output from sawdust downdraft gasification are 800˚C as gasifier temperature and 0.6 for SBR.
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.
文摘Many types of cryptocurrencies,which predominantly utilize blockchain technology,have emerged worldwide.Several issuers plan to circulate their original cryptocurrencies for monetary use.This study investigates whether issuers can stimulate cryptocurrencies to attain a monetary function.We use a multi-agent model,referred to as the Yasutomi model,which simulates the emergence of money.We analyze two scenarios that may result from the actions taken by the issuer.These scenarios focus on increases in the number of stores that accept cryptocurrency payments and situations whereby the cryptocurrency issuer designs the cryptocurrency to be attractive to people and conducts an airdrop.We find that a cryptocurrency can attain a monetary function in two cases.One such case occurs when 20%of all agents accept the cryptocurrency for payment and 50%of the agents are aware of this fact.The second case occurs when the issuer continuously airdrops a cryptocurrency to a specific person while maintaining the total volume of the cryptocurrency within a range that prevents it from losing its attractiveness.
文摘Clean energy is vital for the sustainability of any economy in the world. Many industrialized nations have increased their production capacity of renewable energy while other countries lacking the technical expertise and resource have resorted to import these technologies. The imported technologies mostly have standards that are followed by the manufactures while others are manufactured cheaply and exported to developing countries that do not have adequate standards and certification bodies. Nigeria which is a fast growing country has no existing standards to check the influx of renewable energy technologies into the country. This study stresses the need for the development of standards for renewable energy technologies in order to prevent the importation of substandard renewable energy technologies in Nigeria. The study reviews the renewable energy potentials in Nigeria, introduces the concept of standardization and discusses the development of standards for renewable energy technologies.
文摘A qualitative and quantitative workplace assessment was carried out to determine naphtha exposure in a tyre manufacturing industry. A qualitative chemical health risk assessment was conducted to identify naphtha hazard at the workplace. Quantitative assessment using Portable VOC Monitor, Automatic Sampling Pump and personal air sampling pump was used to determine VOC concentrations, organic solvents, and individual air naphtha respectively. The risk rating of naphtha was estimated to be 5. The mean VOC concentration was in the range of 2.43 to 92.93 ppm. Repair area had the highest VOC concentration while the lowest was in the moulding area. Each work station had significant differences for VOC concentrations （p 〈 0.001）. Laboratory analysis found various solvents including 2-methyl pentane, hexane, methyl cyclopentane, heptane, cyclohexane and toluene which were present in the liquid naphtha. Only xylene has been detected in the making and moulding areas with a range of 2 to 5 ppm. Meanwhile, the air naphtha concentrations of the exposed workers were significantly higher than those unexposed. The risk of naphtha exposure was qualitatively significant and not adequately controlled. Naphtha was detected in all work stations since it is the main solvent used. The ＂Repair Area＂ was significantly more contaminated than the other area.
文摘Differences in knowledge regimes and growth dynamics amongst four ideal types of knowledge based firms are analyzed. Two aspects of technological knowledge, technological opportunity and appropriability are traditionally seen as vital to understand the incentives for research and development activities in firms. However, they do not fully define the technology regimes, when one asks how the knowledge based firm competes. Therefore, the dynamic nature of firm capabilities and knowledge development in terms of expansion and in terms of deepening are also discussed. These two additional aspects of knowledge implies that even if all firms in an industry can be considered to be knowledge intensive these firms do also differ. Using cases of entrepreneurial start-up firms in Sweden, we illustrate whether our conceptual ideas of knowledge development help us understand the diversity and contradictions of firm evolution. Our finding is that firm evolution and capability development is dependent upon both the potential for expanding knowledge, such as by innovations, and by deepening the understanding within established knowledge, such as by learning. This implies that the shaping of a science based industry must be seen in relation both to the value of current knowledge and capabilities together with the sometimes only limited and temporarily advantages of radical innovations.
文摘CO2 emission levels of copper and zinc mines from which Japanese smelters import ore concentrates into Japan,were estimated by using a database called MLED. Eleven copper mines selected from data availability of mine site covered 84% of the total imported concentrates. Adding inventories of sea transportation and smelting processes to mine development process,total CO2 emission level for copper and zinc ingots produced in Japan were calculated. The results show that the emission share of mining and mineral processing processes for each mine is indicated around 30%-70% of total emission for ingots,which implies the importance of including the mining activities to the inventory of upper stream products.
文摘The quality of the drying process depends mainly on the efficient use of thermal energy.Sustainable systems based on solar energy takes a leading role in the drying of agro-products because of low operating cost.However,they are limited in use during off–sun periods.Biomass dryer is one of the simplest ways of drying because of its potential to dry products regardless of time and climate conditions.The other benefit is that crop residues could be used as fuel in these systems.However,the major limitation of the dryer is unequal drying because of poor airflow distribution in the drying medium,which can be improved by integrating some design changes in the dryer.This review analyses the two types of biomass dryers:industrial biomass dryers and small biomass dryers for food product,along with their efficiency.Further,studies on technical,sustainability and economic aspects are expected to provide a greater understanding of biomass drying.
基金supported by the National Natural Science Foundation of China(71831008,72025103,and 72071173)。
文摘1.Uncertainty in maritime transportation Maritime transportation plays a central role in global logistics systems.Over 80%of international trade is carried out via the maritime transportation network[1],which has received widespread attention from academia and industry.In the shipping network,ports are the vertices where large numbers of activities occur,including cargo loading,unloading,and transshipment.Ships sailing between different ports travel along routes that form the links of the network.Shipping operation studies usually cover ship routing,schedule design,fleet deployment,and network design.
文摘A crucial issue in collaborating in manufacturing corporate networks between different companies is to identify to what extent different strategic and operational decisions need to be coordinated between the involved companies. In this paper, we elaborate on the issue of synchronization and coordination of information flow based on interconnectivities between companies in order to coordinate a corporate network by the means of DSM, Dependence Structure Matrix. The results show that DSM can be used to identify interconnectivities, dependencies on information flow among actors in a network and to identify which information needs to be shared between companies in the network.
文摘In recent years,accidents and product recalls caused by product defects have become important problems in numerous industries worldwide.Nevertheless,most existing studies have examined product recalls using empirical approaches.To improve product recall systems,we studied social simulation using a multi-agent system with a co-evolution model.This research is important because empirical approaches are no longer adequate for complex and diverse modern societies.Discussions using quantitative and predictive approaches,including agent-based simulation,are therefore expected.For this study,we used a Layered Co-evolution Model to reflect situations of the real society using producer agents and consumer agents.Additionally,we applied multi-objective optimization techniques to introduce price competition situations into an artificial society.We conducted a simulation experiment,from which we discovered the possibilities that cost reduction for huge-scale product recalls is efficient,and that punishment of producers that conduct no product recalls can benefit consumers.We believe this work can contribute to supporting not only government staff for improving product recall systems,but also executive officers of product companies for deliberating their strategies of recall decisions.
基金supported by the China Scholarship Council(202107940012).
文摘The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.
文摘One promising means to reduce building energy for a more sustainable environment is to conduct early-stage building energy optimization using simulation,yet today’s simulation engines are computationally intensive.Recently,machine learning(ML)energy prediction models have shown promise in replacing these simulation engines.However,it is often difficult to develop such ML models due to the lack of proper datasets.Synthetic datasets can provide a solution,but determining the optimal quantity and diversity of synthetic data remains a challenging task.Furthermore,there is a lack of understanding of the compatibility between different ML algorithms and the characteristics of synthetic datasets.To fill these gaps,this study conducted multiple ML experiments using residential buildings in Sweden to determine the best-performing ML algorithm,as well as the characteristics of the corresponding synthetic dataset.A parametric model was developed to generate a wide range of synthetic datasets varying in size and building shape,referred to as diversity.Five ML algorithms selected through a literature review were trained using the different datasets.Results show that the Support Vector Machine performed the best overall.Multiple Linear Regression performed well with small and lowdiverse datasets,while the Artificial Neural Network performed well with large and high-diverse datasets.We conclude that developers should focus more on increasing diversity instead of size once the dataset size reaches around 1440 when generating synthetic training datasets.This study offers insights for researchers and practitioners,such as software tool developers,when developing ML building energy prediction models in early-stage optimization.
基金supported in part by the National Key Research and Development Program of China(Grant No.2019YFE0118000)in part by the research funding of Guangxi University(No.A3020051008)。
文摘In naval direct current(DC)microgrids,pulsed power loads(PPLs)are becoming more prominent.A solar sys-tem,an energy storage system,and a pulse load coupled directly to the DC bus compose a DC microgrid in this study.For DC mi-crogrids equipped with sonar,radar,and other sensors,pulse load research is crucial.Due to high pulse loads,there is a possibility of severe power pulsation and voltage loss.The original contribution of this paper is that we are able to address the nonlinear problem by applying the Takagi-Sugeno(TS)model formulation for naval DC microgrids.Additionally,we provide a nonlinear power observer for estimating major disturbances affecting DC microgrids.To demonstrate the TS-potential,we examine three approaches for mitigating their negative effects:instantaneous power control(IPC)control,model predictive control(MPC)formulation,and TS-MPC approach with compensated PPLs.The results reveal that the TS-MPC approach with adjusted PPLs effectively shares power and regulates bus voltage under a variety of load conditions,while greatly decreasing detrimental impacts of the pulse load.Additionally,the comparison confirmed the efficiency of this technique.Index Terms-DC microgrids(MG),model predictive control(MPC),pulsed power loads(PPLs),nonlinear power observer,Takagi-Sugeno(TS)fuzzy model.
基金supported by the National Natural Science Founda-tion of China(Grant Nos.72071173 and 71831008).
文摘The 76th session of the Marine Environment Committee(MEPC 76)of the International Maritime Organization adopted several mandatory measures in June 2021 to reduce carbon emissions from ships.One of the measures is the carbon intensity indicator(CII),which is the carbon emissions per unit transport work for each ship.Several options of CIIs are available and none of them is chosen to be applied yet.We prove that,at least in theory,requiring the attained annual CII of a ship to be less than a reference value,no matter which CII option is applied,may increase its carbon emissions.Therefore,more elaborate models,combined with real data,should be developed to analyze the effectiveness of each CII option and possibly to design a new CII.
