The subsurface urban heat island(UHI)effect can provide latent clean geothermal potentials for cities.Understanding the city-wide subsurface temperature evolution under different land surfaces is significant in making...The subsurface urban heat island(UHI)effect can provide latent clean geothermal potentials for cities.Understanding the city-wide subsurface temperature evolution under different land surfaces is significant in making better use of geothermal energy.This research presents a study of Nanjing to identify the city-wide temperature distribution and evolution characteristics and further estimates the geothermal potential in Nanjing.Low-cost satellite-measured temperatures were used to derive the subsurface temperatures through a liner regression correction method,with higher accuracy verified by measured borehole data.The simulation results indicate that the concrete surface exhibits higher average temperatures than the grassland surface,resulting in relatively higher subsurface temperatures.The deviations of simulated subsurface temperatures are attributed to many factors,including the influence of complex atmospheric conditions on satellite-measured temperature accuracy,land surface heat absorption,and infiltration in the shallower layer.Furthermore,it reveals that the urban areas have 14.7%greater geothermal potential compared to rural areas,due to the subsurface UHI effect.This study provides a potentially efficient and convenient method for the estimation of potential urban geothermal energy.展开更多
Increasing distributed generators(DGs)and flexible loads(FLs)enable distribution systems to provide both active and reactive power reserves(P-Q reserves)in supporting the frequency and voltage regulations of transmiss...Increasing distributed generators(DGs)and flexible loads(FLs)enable distribution systems to provide both active and reactive power reserves(P-Q reserves)in supporting the frequency and voltage regulations of transmission systems.However,such requirements at the interface between the transmission system operator(TSO)and distribution system operator(DSO)affect the distribution system operation security,considering the uncertainties of DGs and FLs.To exploit the reserve potential of distribution systems,this paper investigates the voltagedependent P-Q reserve capacity(V-PQRC)of such types of distribution systems.V-PQRC reflects the feasible space of PQ reserves that the DSO can provide to the TSO taking the voltage deviation limit at TSO-DSO interface into consideration,while ensuring the distribution system operation security under uncertainties of DGs and FLs.An evaluation method for VPQRC at the TSO-DSO interface is proposed.To improve the robust performance of the evaluation method,the DG uncertainty is captured by a generalized ambiguity set and the FL uncertainty is addressed by designing a constrained sliding mode controller(CSMC).Three objectives are considered in the evaluation,i.e.,P reserve capacity,Q reserve capacity,and the voltage deviation limit at the TSO-DSO interface.Then,a multiobjective optimization model integrating the generalized robust chance-constrained optimization and CSMC(GRCC-CSMC)is established for V-PQRC evaluation to obtain the Pareto optimal reserve schemes.Finally,a non-approximated selecting(NAS)method is proposed to build up a simplified V-PQRC linear model,which can be convenient to apply in the transmissiondistribution system coordination.Simulation results reveal that the V-PQRC evaluation method can achieve a good performance of accuracy and robustness against uncertainties.展开更多
Based on the analysis of typical lacustrine shale oil zones in China and their geological characteristics,this study elucidates the fundamental differences between the enrichment patterns of shale oil sweet spots and ...Based on the analysis of typical lacustrine shale oil zones in China and their geological characteristics,this study elucidates the fundamental differences between the enrichment patterns of shale oil sweet spots and conventional oil and gas.The key parameters and evaluation methods for assessing the large-scale production potential of lacustrine shale oil are proposed.The results show that shale oil is a petroleum resource that exists in organic-rich shale formations,in other words,it is preserved in its source bed,following a different process of generation-accumulation-enrichment from conventional oil and gas.Thus,the concept of“reservoir”seems to be inapplicable to shale oil.In China,lacustrine shale oil is distributed widely,but the geological characteristics and sweet spots enrichment patterns of shale oil vary significantly in lacustrine basins where the water environment and the tectonic evolution and diagenetic transformation frameworks are distinct.The core of the evaluation of lacustrine shale oil is“sweet spot volume”.The key factors for evaluating the large-scale production of continental shale oil are the oil storage capacity,oil-bearing capacity and oil producing capacity.The key parameters for evaluating these capacities are total porosity,oil content,and free oil content,respectively.It is recommended to determine the total porosity of shale by combining helium porosity measurement with nuclear magnetic resonance(NMR)method,the oil content of key layers by using organic solvent extraction,NMR method and high pressure mercury intrusion methods,and the free oil content by using NMR fluid distribution secondary spectral stripping decomposition and logging.The research results contribute supplemental insights on continental shale oil deliverability in China,and provide a scientific basis for the rapid exploration and large-scale production of lacustrine shale oil.展开更多
The large-scale deployment of electric vehicles(EVs) poses critical challenges to the secure and economic operation of power distribution networks(PDNs). Therefore, a method for evaluating the hosting capacity that en...The large-scale deployment of electric vehicles(EVs) poses critical challenges to the secure and economic operation of power distribution networks(PDNs). Therefore, a method for evaluating the hosting capacity that enables a PDN to determine the EV chargeable area(EVCA) to satisfy the charging demand and ensure the secure operation is proposed in this paper. Specifically, the distribution system operator(DSO) serves as a public entity to manage the integration of EVs by determining the presence of the charging load in the EVCA. Hence, an EVCA optimization model is formulated on the basis of the coupling effect of the charging nodes to determine the range of the available charging power. In this model, nonlinear power flow equations and operational constraints are considered to maintain the solvability of the power flow of the PDN. Subsequently, a novel multipoint approximation technique is proposed to quickly search for the boundary points of the EVCA. In addition, the impact of the demand response(DR) mechanism on the hosting capacity is explored. The results show that the presence of the DR significantly enlarged the EVCA during peak hours, thus revealing the suitability of the DR mechanism as an important supplement to accommodate the EV charging load. The examined case studies demonstrate the effectiveness of the proposed model and show that the unmanaged allocation of the charging load impedes secure operation. Finally, the proposed method provides a reference for the allocation of the EV charging load and a reduction in the risk of line overloading.展开更多
The bearing capacity testing and evaluation of the existing bridge engineering structure is not only the key to clarify its structural quality and safety performance,but it also can lay a solid foundation for subseque...The bearing capacity testing and evaluation of the existing bridge engineering structure is not only the key to clarify its structural quality and safety performance,but it also can lay a solid foundation for subsequent repairs and maintenance work.To ensure the bearing capacity,durability and reliability of existing bridges,this paper analyzes the importance and methods of testing and evaluation of structural bearing capacity of a bridge.This analysis aims to provide scientific reference for the quality assessment and subsequent repair and maintenance of existing bridge engineering structures.展开更多
Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy the...Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy theory, a comprehensive evaluation model on groundwater resources carrying capacity is constructed with blind information. Then a risk assessment model of surcharge about groundwater resources carrying capacity is established on blind reliability theory. The probable value ＂＊＂ matrix of fuzzy membership degree about carrying capacity corresponding to each judgment level can be obtained with the aid of blind algorithm as well as the subjective reliability ＂×＂ matrix. And then a graph of ＂groundwater carrying capacity v.s. accumulative reliability＂ can be gained Based on the graph, fuzzy membership degree of groundwater resources carrying capacity to each judgment level under different risk probability can be got. Thus, a comparatively reasonable judgment to groundwater resources carrying capacity might be obtained, with comprehensive analysis to the state of society, economy technology and ecology.展开更多
In the context of post-stimulation shale gas wells,the terms“shut-in”and“flowback”refer to two critical phases that occur after hydraulic fracturing(fracking)has been completed.These stages play a crucial role in ...In the context of post-stimulation shale gas wells,the terms“shut-in”and“flowback”refer to two critical phases that occur after hydraulic fracturing(fracking)has been completed.These stages play a crucial role in determining both the well’s initial production performance and its long-term hydrocarbon recovery.By establishing a comprehensive big data analysis platform,the flowback dynamics of over 1000 shale gas wells were analyzed in this work,leading to the development of an index system for evaluating flowback production capacity.Additionally,a shut-in chart was created for wells with different types of post-stimulation fracture networks,providing a structured approach to optimizing production strategies.A dynamic analysis method for flowback was also developed,using daily pressure drop and artificial fracture conductivity as key indicators.This method offers a systematic and effective approach to managing the shut-in and flowback processes for gas wells.Field trials demonstrated significant improvements:the probability of sand production was reduced,gas breakthrough time was extended,artificial fracture conductivity was enhanced,and the average estimated ultimate recovery(EUR)per well increased.展开更多
Objective Oil-source faults have an important effect on reservoir formation and distribution in shallow formations with non- hydrocarbon generation in oil-rich fault-related basins （Jiang Youlu et al., 2015）. Howev...Objective Oil-source faults have an important effect on reservoir formation and distribution in shallow formations with non- hydrocarbon generation in oil-rich fault-related basins （Jiang Youlu et al., 2015）. However, the fault transporting capacity cannot be evaluated quantitatively at present. Taking the Zhanhua Sag in the Bohai Bay Basin as an example, this work analyzed the factors influencing the transporting capacity of the oil-source faults and proposed a quantitative method for evaluating their transporting capacity.展开更多
Mismatch negativity is generated automatically, and is an early monitoring indicator of neuronal integrity impairment and functional abnormality in patients with brain injury, leading to decline of cognitive function....Mismatch negativity is generated automatically, and is an early monitoring indicator of neuronal integrity impairment and functional abnormality in patients with brain injury, leading to decline of cognitive function. Antipsychotic medication cannot affect mismatch negativity. The present study aimed to explore the relationships of mismatch negativity with neurocognition, daily life and social functional outcomes in patients after brain injury. Twelve patients with traumatic brain injury and 12 healthy controls were recruited in this study. We examined neurocogni-tion with the Wechsler Adult Intelligence Scale-Revised China, and daily and social functional outcomes with the Activity of Daily Living Scale and Social Disability Screening Schedule, re-spectively. Mismatch negativity was analyzed from electroencephalogram recording. The results showed that mismatch negativity amplitudes decreased in patients with traumatic brain injury compared with healthy controls. Mismatch negativity amplitude was negatively correlated with measurements of neurocognition and positively correlated with functional outcomes in patients after traumatic brain injury. Further, the most signiifcant positive correlations were found be-tween mismatch negativity in the fronto-central region and measures of functional outcomes. The most signiifcant positive correlations were also found between mismatch negativity at the FCz electrode and daily living function. Mismatch negativity amplitudes were extremely positive-ly associated with Social Disability Screening Schedule scores at the Fz electrode in brain injury patients. These experimental ifndings suggest that mismatch negativity might efifciently relfect functional outcomes in patients after traumatic brain injury.展开更多
Cyber physical system(CPS)provides more powerful service by cyber and physical features through the wireless communication.As a kind of social organized network system,a fundamental question of CPS is to achieve servi...Cyber physical system(CPS)provides more powerful service by cyber and physical features through the wireless communication.As a kind of social organized network system,a fundamental question of CPS is to achieve service self-organization with its nodes autonomously working in both physical and cyber environments.To solve the problem,the social nature of nodes in CPS is firstly addressed,and then a formal social semantic descriptions is presented for physical environment,node service and task in order to make the nodes communicate automatically and physical environment sensibly.Further,the Horn clause is introduced to represent the reasoning rules of service organizing.Based on the match function,which is defined for measurement between semantics,the semantic aware measurement is presented to evaluate whether environment around a node can satisfy the task requirement or not.Moreover,the service capacity evaluation method for nodes is addressed to find out the competent service from both cyber and physical features of nodes.According to aforementioned two measurements,the task semantic decomposition algorithm and the organizing matrix are defined and the service self-organizing mechanism for CPS is proposed.Finally,examinations are given to further verify the efficiency and feasibility of the proposed mechanism.展开更多
In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually form...In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually formed,and supports the scale benefit exploration of unconventional gas in China.On this basis,the development theory of"extreme utilization"is proposed,its theoretical connotation together with development technologies of unconventional natural gas are clarified.The theoretical connotation is that,aiming at"extreme gas reservoirs","extreme techniques"are utilized to build subsurface connected bodies,expand the discharge area,and enlarge the production range,to obtain the maximum single-well production,extreme recovery,and eventually achieve the"extreme effect"of production.The series of development technologies include micro/nano-scale reservoir evaluation,"sweet spot"prediction,unconventional percolation theory and production capacity evaluation,optimization of grid well pattern,optimal-fast drilling and volume fracturing,and working regulation optimization and"integrated"organizing system.The"extreme utilization"development theory has been successfully applied in the development of unconventional gas reservoirs such as Sulige tight gas,South Sichuan shale gas,and Qinshui coalbed methane.Such practices demonstrate that,the"extreme utilization"development theory has effectively promoted the development of unconventional gas industry in China,and can provide theoretical guidance for effective development of other potential unconventional and difficult-to-recovery resources.展开更多
The paradigm shift from a coal-based power system to a renewable-energy-based power system brings more challenges to the supply-demand balance of the grid.Distributed energy resources(DERs),which can provide operating...The paradigm shift from a coal-based power system to a renewable-energy-based power system brings more challenges to the supply-demand balance of the grid.Distributed energy resources(DERs),which can provide operating reserve to the grid,are regarded as a promising solution to compensate for the power fluctuation of the renewable energy resources.Small-scale DERs can be aggregated as a virtual power plant(VPP),which is eligible to bid in the operating reserve market.Since the DERs usually belong to different entities,it is important to investigate the VPP operation framework that coordinates the DERs in a trusted man-ner.In this paper,we propose a blockchain-assisted operating reserve framework for VPPs that aggregates various DERs.Considering the heterogeneity of various DERs,we propose a unified reserve capacity evaluation method to facilitate the aggregation of DERs.By considering the mismatch between actual available reserve capacity and the estimated value,the performance of VPP in the operating reserve market is improved.A hardware-based experimental system is developed,and numerical results are presented to demonstrate the effectiveness of the proposed framework.展开更多
基金supports from the National Natural Science Foundation of China(Grant Nos.42222707,41761134089)are gratefully acknowledged.
文摘The subsurface urban heat island(UHI)effect can provide latent clean geothermal potentials for cities.Understanding the city-wide subsurface temperature evolution under different land surfaces is significant in making better use of geothermal energy.This research presents a study of Nanjing to identify the city-wide temperature distribution and evolution characteristics and further estimates the geothermal potential in Nanjing.Low-cost satellite-measured temperatures were used to derive the subsurface temperatures through a liner regression correction method,with higher accuracy verified by measured borehole data.The simulation results indicate that the concrete surface exhibits higher average temperatures than the grassland surface,resulting in relatively higher subsurface temperatures.The deviations of simulated subsurface temperatures are attributed to many factors,including the influence of complex atmospheric conditions on satellite-measured temperature accuracy,land surface heat absorption,and infiltration in the shallower layer.Furthermore,it reveals that the urban areas have 14.7%greater geothermal potential compared to rural areas,due to the subsurface UHI effect.This study provides a potentially efficient and convenient method for the estimation of potential urban geothermal energy.
基金supported by the National Key R&D Program of China(2020YFB0905900)Science and Technology Project of SGCC(State Grid Corporation of China):The key Technologies for Electric Internet of Things(SGTJDK00DWJS2100042).
文摘Increasing distributed generators(DGs)and flexible loads(FLs)enable distribution systems to provide both active and reactive power reserves(P-Q reserves)in supporting the frequency and voltage regulations of transmission systems.However,such requirements at the interface between the transmission system operator(TSO)and distribution system operator(DSO)affect the distribution system operation security,considering the uncertainties of DGs and FLs.To exploit the reserve potential of distribution systems,this paper investigates the voltagedependent P-Q reserve capacity(V-PQRC)of such types of distribution systems.V-PQRC reflects the feasible space of PQ reserves that the DSO can provide to the TSO taking the voltage deviation limit at TSO-DSO interface into consideration,while ensuring the distribution system operation security under uncertainties of DGs and FLs.An evaluation method for VPQRC at the TSO-DSO interface is proposed.To improve the robust performance of the evaluation method,the DG uncertainty is captured by a generalized ambiguity set and the FL uncertainty is addressed by designing a constrained sliding mode controller(CSMC).Three objectives are considered in the evaluation,i.e.,P reserve capacity,Q reserve capacity,and the voltage deviation limit at the TSO-DSO interface.Then,a multiobjective optimization model integrating the generalized robust chance-constrained optimization and CSMC(GRCC-CSMC)is established for V-PQRC evaluation to obtain the Pareto optimal reserve schemes.Finally,a non-approximated selecting(NAS)method is proposed to build up a simplified V-PQRC linear model,which can be convenient to apply in the transmissiondistribution system coordination.Simulation results reveal that the V-PQRC evaluation method can achieve a good performance of accuracy and robustness against uncertainties.
基金Supported by the National Key R&D Program of China(2024YFE0114000)Science and Technology Project of China National Petroleum Corporation(2024DJ8702).
文摘Based on the analysis of typical lacustrine shale oil zones in China and their geological characteristics,this study elucidates the fundamental differences between the enrichment patterns of shale oil sweet spots and conventional oil and gas.The key parameters and evaluation methods for assessing the large-scale production potential of lacustrine shale oil are proposed.The results show that shale oil is a petroleum resource that exists in organic-rich shale formations,in other words,it is preserved in its source bed,following a different process of generation-accumulation-enrichment from conventional oil and gas.Thus,the concept of“reservoir”seems to be inapplicable to shale oil.In China,lacustrine shale oil is distributed widely,but the geological characteristics and sweet spots enrichment patterns of shale oil vary significantly in lacustrine basins where the water environment and the tectonic evolution and diagenetic transformation frameworks are distinct.The core of the evaluation of lacustrine shale oil is“sweet spot volume”.The key factors for evaluating the large-scale production of continental shale oil are the oil storage capacity,oil-bearing capacity and oil producing capacity.The key parameters for evaluating these capacities are total porosity,oil content,and free oil content,respectively.It is recommended to determine the total porosity of shale by combining helium porosity measurement with nuclear magnetic resonance(NMR)method,the oil content of key layers by using organic solvent extraction,NMR method and high pressure mercury intrusion methods,and the free oil content by using NMR fluid distribution secondary spectral stripping decomposition and logging.The research results contribute supplemental insights on continental shale oil deliverability in China,and provide a scientific basis for the rapid exploration and large-scale production of lacustrine shale oil.
基金supported in part by the National Natural Science Foundation of China (No. 52107082)the Natural Science Foundation of Guangxi Province (No. 2021GXNSFBA220032)。
文摘The large-scale deployment of electric vehicles(EVs) poses critical challenges to the secure and economic operation of power distribution networks(PDNs). Therefore, a method for evaluating the hosting capacity that enables a PDN to determine the EV chargeable area(EVCA) to satisfy the charging demand and ensure the secure operation is proposed in this paper. Specifically, the distribution system operator(DSO) serves as a public entity to manage the integration of EVs by determining the presence of the charging load in the EVCA. Hence, an EVCA optimization model is formulated on the basis of the coupling effect of the charging nodes to determine the range of the available charging power. In this model, nonlinear power flow equations and operational constraints are considered to maintain the solvability of the power flow of the PDN. Subsequently, a novel multipoint approximation technique is proposed to quickly search for the boundary points of the EVCA. In addition, the impact of the demand response(DR) mechanism on the hosting capacity is explored. The results show that the presence of the DR significantly enlarged the EVCA during peak hours, thus revealing the suitability of the DR mechanism as an important supplement to accommodate the EV charging load. The examined case studies demonstrate the effectiveness of the proposed model and show that the unmanaged allocation of the charging load impedes secure operation. Finally, the proposed method provides a reference for the allocation of the EV charging load and a reduction in the risk of line overloading.
文摘The bearing capacity testing and evaluation of the existing bridge engineering structure is not only the key to clarify its structural quality and safety performance,but it also can lay a solid foundation for subsequent repairs and maintenance work.To ensure the bearing capacity,durability and reliability of existing bridges,this paper analyzes the importance and methods of testing and evaluation of structural bearing capacity of a bridge.This analysis aims to provide scientific reference for the quality assessment and subsequent repair and maintenance of existing bridge engineering structures.
基金the Key Generalization Program of Science and Tech-nology Achievement of Water Resources Ministry of China (TG0608)
文摘Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy theory, a comprehensive evaluation model on groundwater resources carrying capacity is constructed with blind information. Then a risk assessment model of surcharge about groundwater resources carrying capacity is established on blind reliability theory. The probable value ＂＊＂ matrix of fuzzy membership degree about carrying capacity corresponding to each judgment level can be obtained with the aid of blind algorithm as well as the subjective reliability ＂×＂ matrix. And then a graph of ＂groundwater carrying capacity v.s. accumulative reliability＂ can be gained Based on the graph, fuzzy membership degree of groundwater resources carrying capacity to each judgment level under different risk probability can be got. Thus, a comparatively reasonable judgment to groundwater resources carrying capacity might be obtained, with comprehensive analysis to the state of society, economy technology and ecology.
基金PetroChina Research Applied Science and Technology Project,“Shale Gas Scale Increase Production and Exploration andDevelopment Technology-Research and Application of Key Technology of Deep Shale Gas Scale Production”(No.2023ZZ21YJ01).
文摘In the context of post-stimulation shale gas wells,the terms“shut-in”and“flowback”refer to two critical phases that occur after hydraulic fracturing(fracking)has been completed.These stages play a crucial role in determining both the well’s initial production performance and its long-term hydrocarbon recovery.By establishing a comprehensive big data analysis platform,the flowback dynamics of over 1000 shale gas wells were analyzed in this work,leading to the development of an index system for evaluating flowback production capacity.Additionally,a shut-in chart was created for wells with different types of post-stimulation fracture networks,providing a structured approach to optimizing production strategies.A dynamic analysis method for flowback was also developed,using daily pressure drop and artificial fracture conductivity as key indicators.This method offers a systematic and effective approach to managing the shut-in and flowback processes for gas wells.Field trials demonstrated significant improvements:the probability of sand production was reduced,gas breakthrough time was extended,artificial fracture conductivity was enhanced,and the average estimated ultimate recovery(EUR)per well increased.
基金granted by the National Natural Science Foundation of China(grant No.41672131)Fundamental Research Funds for the Central Universities(grant No.16CX06045A)
文摘Objective Oil-source faults have an important effect on reservoir formation and distribution in shallow formations with non- hydrocarbon generation in oil-rich fault-related basins （Jiang Youlu et al., 2015）. However, the fault transporting capacity cannot be evaluated quantitatively at present. Taking the Zhanhua Sag in the Bohai Bay Basin as an example, this work analyzed the factors influencing the transporting capacity of the oil-source faults and proposed a quantitative method for evaluating their transporting capacity.
基金supported by grants from the National Natural Science Foundation of China,No.81172911,81373251the National High Technology Research and Development Program of China(863 Program),No.2015AA020503+1 种基金the Science and Technology Development Project of Suzhou of China,No.SZP201304Priority Academic Program Development of Jiangsu Higher Education Institutes of China
文摘Mismatch negativity is generated automatically, and is an early monitoring indicator of neuronal integrity impairment and functional abnormality in patients with brain injury, leading to decline of cognitive function. Antipsychotic medication cannot affect mismatch negativity. The present study aimed to explore the relationships of mismatch negativity with neurocognition, daily life and social functional outcomes in patients after brain injury. Twelve patients with traumatic brain injury and 12 healthy controls were recruited in this study. We examined neurocogni-tion with the Wechsler Adult Intelligence Scale-Revised China, and daily and social functional outcomes with the Activity of Daily Living Scale and Social Disability Screening Schedule, re-spectively. Mismatch negativity was analyzed from electroencephalogram recording. The results showed that mismatch negativity amplitudes decreased in patients with traumatic brain injury compared with healthy controls. Mismatch negativity amplitude was negatively correlated with measurements of neurocognition and positively correlated with functional outcomes in patients after traumatic brain injury. Further, the most signiifcant positive correlations were found be-tween mismatch negativity in the fronto-central region and measures of functional outcomes. The most signiifcant positive correlations were also found between mismatch negativity at the FCz electrode and daily living function. Mismatch negativity amplitudes were extremely positive-ly associated with Social Disability Screening Schedule scores at the Fz electrode in brain injury patients. These experimental ifndings suggest that mismatch negativity might efifciently relfect functional outcomes in patients after traumatic brain injury.
基金Supported by the National Natural Science Foundation of China(61103069,71171148)the National High-Tech Research and Development Plan of China(″863″ Plan)(2012BAD35B01)+2 种基金the Innovation Program of Shanghai Municipal Education Commission(13YZ052)the Shanghai Committee of Science and Technology(11DZ1501703,11dz12106001)the Program of Shanghai Normal University(DXL125,DCL201302)
文摘Cyber physical system(CPS)provides more powerful service by cyber and physical features through the wireless communication.As a kind of social organized network system,a fundamental question of CPS is to achieve service self-organization with its nodes autonomously working in both physical and cyber environments.To solve the problem,the social nature of nodes in CPS is firstly addressed,and then a formal social semantic descriptions is presented for physical environment,node service and task in order to make the nodes communicate automatically and physical environment sensibly.Further,the Horn clause is introduced to represent the reasoning rules of service organizing.Based on the match function,which is defined for measurement between semantics,the semantic aware measurement is presented to evaluate whether environment around a node can satisfy the task requirement or not.Moreover,the service capacity evaluation method for nodes is addressed to find out the competent service from both cyber and physical features of nodes.According to aforementioned two measurements,the task semantic decomposition algorithm and the organizing matrix are defined and the service self-organizing mechanism for CPS is proposed.Finally,examinations are given to further verify the efficiency and feasibility of the proposed mechanism.
基金Supported by the China National Science and Technology Major Project(2017ZX05035,2016ZX05037)。
文摘In the process of unconventional natural gas development practice,the"extreme utilization"concept that focuses on"continuously breaking through the limit of development technology"is gradually formed,and supports the scale benefit exploration of unconventional gas in China.On this basis,the development theory of"extreme utilization"is proposed,its theoretical connotation together with development technologies of unconventional natural gas are clarified.The theoretical connotation is that,aiming at"extreme gas reservoirs","extreme techniques"are utilized to build subsurface connected bodies,expand the discharge area,and enlarge the production range,to obtain the maximum single-well production,extreme recovery,and eventually achieve the"extreme effect"of production.The series of development technologies include micro/nano-scale reservoir evaluation,"sweet spot"prediction,unconventional percolation theory and production capacity evaluation,optimization of grid well pattern,optimal-fast drilling and volume fracturing,and working regulation optimization and"integrated"organizing system.The"extreme utilization"development theory has been successfully applied in the development of unconventional gas reservoirs such as Sulige tight gas,South Sichuan shale gas,and Qinshui coalbed methane.Such practices demonstrate that,the"extreme utilization"development theory has effectively promoted the development of unconventional gas industry in China,and can provide theoretical guidance for effective development of other potential unconventional and difficult-to-recovery resources.
基金The Science and Technology Development Fund,Macao SAR(File No.0011/2022/AGJFile No.SKL-IOTSC(UM)-2021-2023).
文摘The paradigm shift from a coal-based power system to a renewable-energy-based power system brings more challenges to the supply-demand balance of the grid.Distributed energy resources(DERs),which can provide operating reserve to the grid,are regarded as a promising solution to compensate for the power fluctuation of the renewable energy resources.Small-scale DERs can be aggregated as a virtual power plant(VPP),which is eligible to bid in the operating reserve market.Since the DERs usually belong to different entities,it is important to investigate the VPP operation framework that coordinates the DERs in a trusted man-ner.In this paper,we propose a blockchain-assisted operating reserve framework for VPPs that aggregates various DERs.Considering the heterogeneity of various DERs,we propose a unified reserve capacity evaluation method to facilitate the aggregation of DERs.By considering the mismatch between actual available reserve capacity and the estimated value,the performance of VPP in the operating reserve market is improved.A hardware-based experimental system is developed,and numerical results are presented to demonstrate the effectiveness of the proposed framework.
