Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the ...Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.展开更多
In this paper,we propose STPLF,which stands for the short-term forecasting of locational marginal price components,including the forecasting of non-conforming hourly net loads.The volatility of transmission-level hour...In this paper,we propose STPLF,which stands for the short-term forecasting of locational marginal price components,including the forecasting of non-conforming hourly net loads.The volatility of transmission-level hourly locational marginal prices(LMPs)is caused by several factors,including weather data,hourly gas prices,historical hourly loads,and market prices.In addition,variations of non-conforming net loads,which are affected by behind-the-meter distributed energy resources(DERs)and retail customer loads,could have a major impact on the volatility of hourly LMPs,as bulk grid operators have limited visibility of such retail-level resources.We propose a fusion forecasting model for the STPLF,which uses machine learning and deep learning methods to forecast non-conforming loads and respective hourly prices.Additionally,data preprocessing and feature extraction are used to increase the accuracy of the STPLF.The proposed STPLF model also includes a post-processing stage for calculating the probability of hourly LMP spikes.We use a practical set of data to analyze the STPLF results and validate the proposed probabilistic method for calculating the LMP spikes.展开更多
Using datasets on high-tech industries in Beijing as empirical studies, this paper attempts to interpret spatial shift of high-tech manufacturing firms and to examine the main determinants that have had the greatest e...Using datasets on high-tech industries in Beijing as empirical studies, this paper attempts to interpret spatial shift of high-tech manufacturing firms and to examine the main determinants that have had the greatest effect on this spatial evolution. We aimed at merging these two aspects by using firm level databases in 1996 and 2010. To explain spatial change of the high-tech firms in Beijing, the Kernel density estimation method was used for hotspot analysis and detection by comparing their locations in 1996 and 2010, through which spatial features and their temporal changes could be approximately plotted. Furthermore, to provide quantitative results, Ripley′s K-function was used as an instrument to reveal spatial shift and the dispersion distance of high-tech manufacturing firms in Beijing. By employing a negative binominal regression model, we evaluated the main determinants that have significantly affected the spatial evolution of high-tech manufacturing firms and compared differential influence of these locational factors on overall high-tech firms and each sub-sectors. The empirical analysis shows that high-tech industries in Beijing, in general, have evident agglomeration characteristics, and that the hotspot has shifted from the central city to suburban areas. In combination with the Ripley index, this study concludes that high-tech firms are now more scattered in metropolitan areas of Beijing as compared with 1996. The results of regression model indicate that the firms′ locational decisions are significantly influenced by the spatial planning and regulation policies of the municipal government. In addition, market processes involving transportation accessibility and agglomeration economy have been found to be important in explaining the dynamics of locational variation of high-tech manufacturing firms in Beijing. Research into how markets and the government interact to determine the location of high-tech manufacturing production will be helpful for policymakers to enact effective policies toward a more efficient urban spatial structure.展开更多
There exists an inherent relationship between territorial division of labour and locational superiorities,of which becomes a basic point followed in the process of regional development and urban planning.The historica...There exists an inherent relationship between territorial division of labour and locational superiorities,of which becomes a basic point followed in the process of regional development and urban planning.The historical evolution of territorial division theories is reviewed first.The authors fully appraise the contributions of A.Smith et al.and comment on some of their shortcomings.An integrated system on locational superiorities is then put forward which contains four pairs of regional or urban superiorities.Finally,the relation of external elements and inherent mechanism in areal differentiation is probed.展开更多
This study was aimed at assessing the locational compliance status of petroleum handling facilities in the Niger Delta to the specifications of the Nigerian Upstream Petroleum Regulatory Commission (NUPRC) locational ...This study was aimed at assessing the locational compliance status of petroleum handling facilities in the Niger Delta to the specifications of the Nigerian Upstream Petroleum Regulatory Commission (NUPRC) locational standards. A cross-sectional research design was employed using a Standard checklist of seventeen compliance specifications of NUPRC. A walk-through survey was carried out in 118 identified facilities in three locations: Eket in Akwa-Ibom State, Port Harcourt in Rivers State and Warri in Delta State, respectively. The data obtained were analyzed using inferential and descriptive statistics, Kendall Tau-B and Principal Component analyses. The results indicate that the Petroleum Product facilities complied with 6 (35.29%) out of 17 specifications while 11 (64.70%) specifications were violated. Locations compliance of stations in the Niger Delta region is generally poor, but Stations in Port Harcourt recorded a higher compliance rate compared to Eket and Warri. Results of Kendall’s tau-b and Principal Component analysis indicated positive association between all the land space locational compliances. This study attributes the poor compliance rate to rapid urbanization, overpopulation, proliferation of filling stations and poor monitoring by regulatory agencies. It is recommended that, NUPRC should improve its monitoring and enforce regulatory operational specifications.展开更多
Foreign direct investments (or FDIs) have been employed since the early 1980s and they have become more and more immportant in Chinese economic development. However, the roles of FDIs are very different between region...Foreign direct investments (or FDIs) have been employed since the early 1980s and they have become more and more immportant in Chinese economic development. However, the roles of FDIs are very different between regions, partly due to the different locational preference of various source countries. Some facts show that FDIs from Hongkong - Macao indicate a strong locational preference. Therefore, this paper attempts to make an empirical research on the locational preference of Hongkong - Macao’s FDIs and their spatial diffusion under the support of statistical data with regrereion analysis. In this paper, three statistical models, including the special location model, the general location model and the spatial diffusion model, are created. The results show that this kind of analysis is successful. The major conclusions are as follows. (1) The optimum location for FDIs from Hongkong - Macao lies in the coastal area, especially Guangdong, Hainan, Jiangsu, Shandong, Fujian provinces. Besides, Hubei Province is also an important radon. (2) The FDIs from HongkongMacao in China have diffused gradually from the coastal provinces to the inland regions, the northem and the metropolis and from the locations that had attracted a large number of investments to their vicinities since the 1990s. (3) The special location factors, such as the herder effect, the unique social and kinship ties are the key factors determining the special locational distribution. (4) The general location and spatial diffusion of Hongkong - Macao’s FDIs are the results of interplay of several economic factors. They are the economic scale and advantage, the growth rate, the laier force and economic extrovert etc.展开更多
The study shows that the regional differentiation of Hong Kong direct investement(HKDI) in China was enlarged in the 1980s and has has reducing since 1991. The concentration of HKDI in the southern China and the coast...The study shows that the regional differentiation of Hong Kong direct investement(HKDI) in China was enlarged in the 1980s and has has reducing since 1991. The concentration of HKDI in the southern China and the coast has has replace by the trend of moving northwards and iulandwards after 1989. But in terms of tnanofacturing sectors this trend has not clearly appeared until now. Those changing Patterns are dearly related to the behaviour of Hong Kong industrial investors.The survey results suggest that 'enjoying lower production cost' is the most important motive for thed investment in China. In consequece, 'close to Hong Kong','cheqper labour' and 'favourable policy' are major factors for determining the investment locations. This behaviour, together with the lack of comparison study in location selection among most investors, explains that Guangdong absorbed most Hong Kong investment in the 1980s. As the production costs have been increasing in Guangdong, are companies have started to invest in non-Guangdong locations since the end of the 1980s. From the mental map of Hong Kong investors, however, only some of the non-Guangdong locations are practically attractive.展开更多
Peer-to-peer(P2P)energy trading enables an efficient regulation of distributed renewable energy among prosumers,implicitly promoting low-carbon operation.This study proposes a novel P2P energy trading scheme with coup...Peer-to-peer(P2P)energy trading enables an efficient regulation of distributed renewable energy among prosumers,implicitly promoting low-carbon operation.This study proposes a novel P2P energy trading scheme with coupled electricity-carbon(E/C)market that co-optimizes both power and carbon emission flows.To facilitate the low-carbon operations in the market,we introduce a prosumer-driven carbon-aware distribution locational marginal price(PDC-DLMP)to serve as a pricing signal for the distribution system operator(DSO).To efficiently determine the optimal trading solutions,we adopt a two-layer data-driven approach.The first layer employs a reinforcement learning algorithm named multi-agent twin-delayed deep deterministic policy gradient(MATD3);the second layer uses a deep neural network(DNN)driven surrogate model,which is designed to map the PDC-DLMP signals,thereby eliminating the need for direct DSO intervention during market operation.This approach protects the physical model parameters of the distribution network and ensures multi-level privacy protection.Simulation results validate the effectiveness of the proposed P2P energy trading scheme with coupled E/C market,demonstrating its ability to achieve both reduced carbon emissions and lower operational costs for microgrid prosumers.展开更多
Decarbonisation of power systems is essential for realising carbon neutrality,in which the economic cost caused by carbon needs to be qualified.Based on the formulation of locational marginal price(LMP),this paper pro...Decarbonisation of power systems is essential for realising carbon neutrality,in which the economic cost caused by carbon needs to be qualified.Based on the formulation of locational marginal price(LMP),this paper proposes a locational marginal electricity-carbon price(EC-LMP)model to reveal carbon-related costs caused by power consumers.A carbon-priceintegrated optimal power flow(C-OPF)is then developed to maximise economic efficiency of the power system considering the costs of electricity and carbon.Case studies are presented to demonstrate the new formulation and results demonstrate the efficacy of the EC-LMP-based C-OPF on decarbonisation and economy.展开更多
The large-scale integration of renewable energy sources (RESs) brings huge challenges to the power system. A cost-effective reserve deployment and uncertainty pricing mechanism are critical to deal with the uncertaint...The large-scale integration of renewable energy sources (RESs) brings huge challenges to the power system. A cost-effective reserve deployment and uncertainty pricing mechanism are critical to deal with the uncertainty and variability of RES. To this end, this paper proposes a novel locational marginal pricing mechanism in day-ahead market for managing uncertainties from RES. Firstly, an improved multi-ellipsoidal uncertainty set (IMEUS) considering the temporal correlation and conditional correlation of wind power forecasting is formulated to better capture the uncertainty of wind power. The dimension of each ellipsoidal subset is optimized based on a comprehensive evaluation index to reduce the invalid region without large loss of modeling accuracy, so as to reduce the conservatism. Then, an IMEUS-based robust unit commitment (RUC) model and a robust economic dispatch (RED) model are established for the day-ahead market clearing. Both the reserve cost and ramping constraints are considered in the overall dispatch process. Furthermore, based on the Langrangian function of the RED model, a new locational marginal pricing mechanism is developed. The uncertainty locational marginal price (ULMP) is introduced to charge the RES for its uncertainties and reward the generators who provide reserve to mitigate uncertainties. The new pricing mechanism can provide effective price signals to incentivize the uncertainty management in the day-ahead market. Finally, the effectiveness of the proposed mechanism is verified via numerous simulations on the PJM 5-bus system and IEEE 118-bus system.展开更多
With the increasing penetration of renewables,power systems have to operate with greater flexibility to address the uncertainties of renewable output.This paper develops an uncertainty locational marginal price(ULMP)m...With the increasing penetration of renewables,power systems have to operate with greater flexibility to address the uncertainties of renewable output.This paper develops an uncertainty locational marginal price(ULMP)mechanism to price these uncertainties.They are denoted as box deviation intervals as suggested by the market participants.The ULMP model solves a robust optimal power flow(OPF)problem to clear market bids,aiming to minimize the system cost as a prerequisite that the reserve margin can address all the relevant uncertainties.The ULMP can be obtained as a by-product of the optimization problem from the Lagrange multipliers.Under the ULMP mechanism,renewables and consumers with uncertainty will make extra payments,and the thermals and financial transmission right(FTR)holders will be compensated.It is further shown that the proposed mechanism has preferable properties,such as social efficiency,budget balance and individual rationality.Numerical tests are conducted on the modified IEEE 5-bus and 118-bus systems to demonstrate the merits and applicability of the proposed mechanism.展开更多
Market power is known as the ability of units and generation companies(GenCos)to change electricity price profitably.As cleared in the definition,locational marginal price(LMP)is the most important key in market power...Market power is known as the ability of units and generation companies(GenCos)to change electricity price profitably.As cleared in the definition,locational marginal price(LMP)is the most important key in market power evaluation.Therefore,the main objective of the paper is to analyze market power of units and GenCos based on their abilities to change electricity price.At the first step,using Karush-Kuhn-Tucker(KKT)conditions of Lagrangian method,LMP is decomposed into four main components.These components indicate the share of each unit at the LMP of each bus.These values are calculated by the proposed analytical method,and cannot be obtained using simulation methods.At the second step,"unit-based LMP share(LMP_S)"index,which indicates the contribution factor of each unit at LMP of each bus,is proposed as a new structural market power index.This index is also used as an effective tool to determine the most profitable coalition between two units.Using that,the market operator can predict highly potential collusions.Moreover,"GenCosbased LMP_S"index is proposed.Using this effective tool,the contribution of each GenCo,which owns multiple units at various buses,at the LMP of each bus is discovered.The proposed market power indices are calculated on the IEEE24-bus test system and compared with some conventional structural market power indices.Incremental profits of units due to change of unit’s strategies verify the accuracy of the proposed method.展开更多
This paper examines the impact of power transmission network topology change on locational marginal price(LMP) in real-time power markets. We consider the case where the false status of circuit breakers(CBs) that bypa...This paper examines the impact of power transmission network topology change on locational marginal price(LMP) in real-time power markets. We consider the case where the false status of circuit breakers(CBs) that bypass topology error processing can generate an incorrect power system network topology, subsequently distorting the results of the state estimation and economic dispatch.The main goal of this paper is to assess the economic impact of this misconfigured network topology on realtime LMP in an entire power system with network congestion. To this end, we start with our prior result, a simple and analytical congestion price equation, which can be applied to any single line congestion scenario. This equation can be extended to better understand the degree to which the LMP at any bus changes due to any line status error. Furthermore, it enables a rigorous analysis of the relationship between the change in LMP at any bus with respect to any line error and various physical/economical grid conditions such as the bidding prices for marginal generators and the locations of the congested/erroneous lines. Numerical examples on the impact analysis of this topology error are illustrated in IEEE 14-bus and 118-bus systems.展开更多
This paper proposes a distribution locational marginal pricing(DLMP) based bi-level Stackelberg game framework between the internet service company(ISC) and distribution system operator(DSO) in the data center park. T...This paper proposes a distribution locational marginal pricing(DLMP) based bi-level Stackelberg game framework between the internet service company(ISC) and distribution system operator(DSO) in the data center park. To minimize electricity costs, the ISC at the upper level dispatches the interactive workloads(IWs) across different data center buildings spatially and schedules the battery energy storage system temporally in response to DLMP. Photovoltaic generation and static var generation provide extra active and reactive power. At the lower level, DSO calculates the DLMP by minimizing the total electricity cost under the two-part tariff policy and ensures that the distribution network is uncongested and bus voltage is within the limit. The equilibrium solution is obtained by converting the bi-level optimization into a single-level mixed-integer second-order cone programming optimization using the strong duality theorem and the binary expansion method. Case studies verify that the proposed method benefits both the DSO and ISC while preserving the privacy of the ISC. By taking into account the uncertainties in IWs and photovoltaic generation, the flexibility of distribution networks is enhanced, which further facilitates the accommodation of more demand-side resources.展开更多
An iterative method based on Shapley Value Cooperative Game Theory is proposed for the calculation of local marginal price (LMP) for each Distributed Generator (DG) bus on a network. The LMP value is determined for ea...An iterative method based on Shapley Value Cooperative Game Theory is proposed for the calculation of local marginal price (LMP) for each Distributed Generator (DG) bus on a network. The LMP value is determined for each DG on the basis of its contribution to reduce loss and emission reduction, which is assessed using the Shapley Value approach. The proposed approach enables the Distribution Company (DISCO) decision-maker to operate the network optimally in terms of loss and emission. The proposed method is implemented in the Taiwan Power Company distribution network 7 warnings consisting of 84 buses and 11 feeders in the MATLAB environment. The results show that the proposed approach allows DISCO to operate the network on the basis of its priority between the reduction of active power loss and emission in the network.展开更多
Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the m...Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.展开更多
Power system resilience procurement costs in N-k contingencies have gained more prominence as number of extreme events continues to increase.A chain rule is presented in this paper for extracting resilience procuremen...Power system resilience procurement costs in N-k contingencies have gained more prominence as number of extreme events continues to increase.A chain rule is presented in this paper for extracting resilience procurement costs from a fully decomposed locational marginal price(LMP)model.First,power transfer distribution factor(PTDF)matrices with AC power flow(i.e.,AC-PTDF)are determined.AC-PTDF and AC-LODF(line outage distribution factor)equations are derived for N-k contingencies and a fully decomposed LMP model is developed where generation and transmission security components are established for specific contingencies.Furthermore,resilience procurement costs can be measured at different buses for the proposed security components.Impact of N-k contingencies on resilience procurement costs at specific buses can be determined as proposed security components will gain more insight for resilience procurement in power systems.The modified IEEE 6-bus and 118-bus systems are adopted to verify effectiveness of the proposed resilience procurement method.展开更多
Salzburg is a beautiful city in Austria.It has old buildings,pretty streets and big mountains all around.The scenery is amazing!The famous movie The Sound of Music was filmed there.Many people visit Salzburg to see th...Salzburg is a beautiful city in Austria.It has old buildings,pretty streets and big mountains all around.The scenery is amazing!The famous movie The Sound of Music was filmed there.Many people visit Salzburg to see the locations from the movie.Some even do interviews there to ask people their feelings about the movie.One famous location from the movie is the Mirabell Gardens.The actors sang the song"Do-Re-Mi"there.The gardens have colorful flowers,statues and fountains.Salzburg is a fun and exciting place to visit and explore.展开更多
The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,...The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.展开更多
Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special ...Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special customs operations at the end of 2025,private enterprises operating at its Yangpu Port began to benefit substantially from the favorable policies and surging growth momentum in the region.While riding on an ocean of opportunities opened by the FTP,local businesses are bringing the island to a new level of prosperity,and thriving together with it as a community of shared future.展开更多
基金Major Program of National Social Science Foundation of China,No.21&ZD107。
文摘Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.
基金funded in part by Grant No.DF-091-135-1441 from the Deanship of Scientific Research(DSR)at King Abdulaziz University in Saudi Arabia.
文摘In this paper,we propose STPLF,which stands for the short-term forecasting of locational marginal price components,including the forecasting of non-conforming hourly net loads.The volatility of transmission-level hourly locational marginal prices(LMPs)is caused by several factors,including weather data,hourly gas prices,historical hourly loads,and market prices.In addition,variations of non-conforming net loads,which are affected by behind-the-meter distributed energy resources(DERs)and retail customer loads,could have a major impact on the volatility of hourly LMPs,as bulk grid operators have limited visibility of such retail-level resources.We propose a fusion forecasting model for the STPLF,which uses machine learning and deep learning methods to forecast non-conforming loads and respective hourly prices.Additionally,data preprocessing and feature extraction are used to increase the accuracy of the STPLF.The proposed STPLF model also includes a post-processing stage for calculating the probability of hourly LMP spikes.We use a practical set of data to analyze the STPLF results and validate the proposed probabilistic method for calculating the LMP spikes.
基金Under the auspices of National Natural Science Foundation of China(No.40971075)
文摘Using datasets on high-tech industries in Beijing as empirical studies, this paper attempts to interpret spatial shift of high-tech manufacturing firms and to examine the main determinants that have had the greatest effect on this spatial evolution. We aimed at merging these two aspects by using firm level databases in 1996 and 2010. To explain spatial change of the high-tech firms in Beijing, the Kernel density estimation method was used for hotspot analysis and detection by comparing their locations in 1996 and 2010, through which spatial features and their temporal changes could be approximately plotted. Furthermore, to provide quantitative results, Ripley′s K-function was used as an instrument to reveal spatial shift and the dispersion distance of high-tech manufacturing firms in Beijing. By employing a negative binominal regression model, we evaluated the main determinants that have significantly affected the spatial evolution of high-tech manufacturing firms and compared differential influence of these locational factors on overall high-tech firms and each sub-sectors. The empirical analysis shows that high-tech industries in Beijing, in general, have evident agglomeration characteristics, and that the hotspot has shifted from the central city to suburban areas. In combination with the Ripley index, this study concludes that high-tech firms are now more scattered in metropolitan areas of Beijing as compared with 1996. The results of regression model indicate that the firms′ locational decisions are significantly influenced by the spatial planning and regulation policies of the municipal government. In addition, market processes involving transportation accessibility and agglomeration economy have been found to be important in explaining the dynamics of locational variation of high-tech manufacturing firms in Beijing. Research into how markets and the government interact to determine the location of high-tech manufacturing production will be helpful for policymakers to enact effective policies toward a more efficient urban spatial structure.
文摘There exists an inherent relationship between territorial division of labour and locational superiorities,of which becomes a basic point followed in the process of regional development and urban planning.The historical evolution of territorial division theories is reviewed first.The authors fully appraise the contributions of A.Smith et al.and comment on some of their shortcomings.An integrated system on locational superiorities is then put forward which contains four pairs of regional or urban superiorities.Finally,the relation of external elements and inherent mechanism in areal differentiation is probed.
文摘This study was aimed at assessing the locational compliance status of petroleum handling facilities in the Niger Delta to the specifications of the Nigerian Upstream Petroleum Regulatory Commission (NUPRC) locational standards. A cross-sectional research design was employed using a Standard checklist of seventeen compliance specifications of NUPRC. A walk-through survey was carried out in 118 identified facilities in three locations: Eket in Akwa-Ibom State, Port Harcourt in Rivers State and Warri in Delta State, respectively. The data obtained were analyzed using inferential and descriptive statistics, Kendall Tau-B and Principal Component analyses. The results indicate that the Petroleum Product facilities complied with 6 (35.29%) out of 17 specifications while 11 (64.70%) specifications were violated. Locations compliance of stations in the Niger Delta region is generally poor, but Stations in Port Harcourt recorded a higher compliance rate compared to Eket and Warri. Results of Kendall’s tau-b and Principal Component analysis indicated positive association between all the land space locational compliances. This study attributes the poor compliance rate to rapid urbanization, overpopulation, proliferation of filling stations and poor monitoring by regulatory agencies. It is recommended that, NUPRC should improve its monitoring and enforce regulatory operational specifications.
文摘Foreign direct investments (or FDIs) have been employed since the early 1980s and they have become more and more immportant in Chinese economic development. However, the roles of FDIs are very different between regions, partly due to the different locational preference of various source countries. Some facts show that FDIs from Hongkong - Macao indicate a strong locational preference. Therefore, this paper attempts to make an empirical research on the locational preference of Hongkong - Macao’s FDIs and their spatial diffusion under the support of statistical data with regrereion analysis. In this paper, three statistical models, including the special location model, the general location model and the spatial diffusion model, are created. The results show that this kind of analysis is successful. The major conclusions are as follows. (1) The optimum location for FDIs from Hongkong - Macao lies in the coastal area, especially Guangdong, Hainan, Jiangsu, Shandong, Fujian provinces. Besides, Hubei Province is also an important radon. (2) The FDIs from HongkongMacao in China have diffused gradually from the coastal provinces to the inland regions, the northem and the metropolis and from the locations that had attracted a large number of investments to their vicinities since the 1990s. (3) The special location factors, such as the herder effect, the unique social and kinship ties are the key factors determining the special locational distribution. (4) The general location and spatial diffusion of Hongkong - Macao’s FDIs are the results of interplay of several economic factors. They are the economic scale and advantage, the growth rate, the laier force and economic extrovert etc.
文摘The study shows that the regional differentiation of Hong Kong direct investement(HKDI) in China was enlarged in the 1980s and has has reducing since 1991. The concentration of HKDI in the southern China and the coast has has replace by the trend of moving northwards and iulandwards after 1989. But in terms of tnanofacturing sectors this trend has not clearly appeared until now. Those changing Patterns are dearly related to the behaviour of Hong Kong industrial investors.The survey results suggest that 'enjoying lower production cost' is the most important motive for thed investment in China. In consequece, 'close to Hong Kong','cheqper labour' and 'favourable policy' are major factors for determining the investment locations. This behaviour, together with the lack of comparison study in location selection among most investors, explains that Guangdong absorbed most Hong Kong investment in the 1980s. As the production costs have been increasing in Guangdong, are companies have started to invest in non-Guangdong locations since the end of the 1980s. From the mental map of Hong Kong investors, however, only some of the non-Guangdong locations are practically attractive.
基金supported in part by the National Natural Science Foundation of China(No.52107100)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX24-0657)。
文摘Peer-to-peer(P2P)energy trading enables an efficient regulation of distributed renewable energy among prosumers,implicitly promoting low-carbon operation.This study proposes a novel P2P energy trading scheme with coupled electricity-carbon(E/C)market that co-optimizes both power and carbon emission flows.To facilitate the low-carbon operations in the market,we introduce a prosumer-driven carbon-aware distribution locational marginal price(PDC-DLMP)to serve as a pricing signal for the distribution system operator(DSO).To efficiently determine the optimal trading solutions,we adopt a two-layer data-driven approach.The first layer employs a reinforcement learning algorithm named multi-agent twin-delayed deep deterministic policy gradient(MATD3);the second layer uses a deep neural network(DNN)driven surrogate model,which is designed to map the PDC-DLMP signals,thereby eliminating the need for direct DSO intervention during market operation.This approach protects the physical model parameters of the distribution network and ensures multi-level privacy protection.Simulation results validate the effectiveness of the proposed P2P energy trading scheme with coupled E/C market,demonstrating its ability to achieve both reduced carbon emissions and lower operational costs for microgrid prosumers.
基金supported by the National Natural Science Foundation of China(U2166211).
文摘Decarbonisation of power systems is essential for realising carbon neutrality,in which the economic cost caused by carbon needs to be qualified.Based on the formulation of locational marginal price(LMP),this paper proposes a locational marginal electricity-carbon price(EC-LMP)model to reveal carbon-related costs caused by power consumers.A carbon-priceintegrated optimal power flow(C-OPF)is then developed to maximise economic efficiency of the power system considering the costs of electricity and carbon.Case studies are presented to demonstrate the new formulation and results demonstrate the efficacy of the EC-LMP-based C-OPF on decarbonisation and economy.
基金This work was supported in part by the National Key R&D Program of Chi‐na(No.2020YFE0200400)the National Nature Science Foundation of Chi‐na(No.51907140).
文摘The large-scale integration of renewable energy sources (RESs) brings huge challenges to the power system. A cost-effective reserve deployment and uncertainty pricing mechanism are critical to deal with the uncertainty and variability of RES. To this end, this paper proposes a novel locational marginal pricing mechanism in day-ahead market for managing uncertainties from RES. Firstly, an improved multi-ellipsoidal uncertainty set (IMEUS) considering the temporal correlation and conditional correlation of wind power forecasting is formulated to better capture the uncertainty of wind power. The dimension of each ellipsoidal subset is optimized based on a comprehensive evaluation index to reduce the invalid region without large loss of modeling accuracy, so as to reduce the conservatism. Then, an IMEUS-based robust unit commitment (RUC) model and a robust economic dispatch (RED) model are established for the day-ahead market clearing. Both the reserve cost and ramping constraints are considered in the overall dispatch process. Furthermore, based on the Langrangian function of the RED model, a new locational marginal pricing mechanism is developed. The uncertainty locational marginal price (ULMP) is introduced to charge the RES for its uncertainties and reward the generators who provide reserve to mitigate uncertainties. The new pricing mechanism can provide effective price signals to incentivize the uncertainty management in the day-ahead market. Finally, the effectiveness of the proposed mechanism is verified via numerous simulations on the PJM 5-bus system and IEEE 118-bus system.
基金supported in part by the National Natural Science Foundation of China(No.51620105007)in part the UNSW(University of New South Wales)&Tsinghua University Collaborative Research Fund(RG193827/2018Z)。
文摘With the increasing penetration of renewables,power systems have to operate with greater flexibility to address the uncertainties of renewable output.This paper develops an uncertainty locational marginal price(ULMP)mechanism to price these uncertainties.They are denoted as box deviation intervals as suggested by the market participants.The ULMP model solves a robust optimal power flow(OPF)problem to clear market bids,aiming to minimize the system cost as a prerequisite that the reserve margin can address all the relevant uncertainties.The ULMP can be obtained as a by-product of the optimization problem from the Lagrange multipliers.Under the ULMP mechanism,renewables and consumers with uncertainty will make extra payments,and the thermals and financial transmission right(FTR)holders will be compensated.It is further shown that the proposed mechanism has preferable properties,such as social efficiency,budget balance and individual rationality.Numerical tests are conducted on the modified IEEE 5-bus and 118-bus systems to demonstrate the merits and applicability of the proposed mechanism.
文摘Market power is known as the ability of units and generation companies(GenCos)to change electricity price profitably.As cleared in the definition,locational marginal price(LMP)is the most important key in market power evaluation.Therefore,the main objective of the paper is to analyze market power of units and GenCos based on their abilities to change electricity price.At the first step,using Karush-Kuhn-Tucker(KKT)conditions of Lagrangian method,LMP is decomposed into four main components.These components indicate the share of each unit at the LMP of each bus.These values are calculated by the proposed analytical method,and cannot be obtained using simulation methods.At the second step,"unit-based LMP share(LMP_S)"index,which indicates the contribution factor of each unit at LMP of each bus,is proposed as a new structural market power index.This index is also used as an effective tool to determine the most profitable coalition between two units.Using that,the market operator can predict highly potential collusions.Moreover,"GenCosbased LMP_S"index is proposed.Using this effective tool,the contribution of each GenCo,which owns multiple units at various buses,at the LMP of each bus is discovered.The proposed market power indices are calculated on the IEEE24-bus test system and compared with some conventional structural market power indices.Incremental profits of units due to change of unit’s strategies verify the accuracy of the proposed method.
基金supported in part by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(No.2015R1C1A1A01051890)part by the National Science Foundation DGE-1303378
文摘This paper examines the impact of power transmission network topology change on locational marginal price(LMP) in real-time power markets. We consider the case where the false status of circuit breakers(CBs) that bypass topology error processing can generate an incorrect power system network topology, subsequently distorting the results of the state estimation and economic dispatch.The main goal of this paper is to assess the economic impact of this misconfigured network topology on realtime LMP in an entire power system with network congestion. To this end, we start with our prior result, a simple and analytical congestion price equation, which can be applied to any single line congestion scenario. This equation can be extended to better understand the degree to which the LMP at any bus changes due to any line status error. Furthermore, it enables a rigorous analysis of the relationship between the change in LMP at any bus with respect to any line error and various physical/economical grid conditions such as the bidding prices for marginal generators and the locations of the congested/erroneous lines. Numerical examples on the impact analysis of this topology error are illustrated in IEEE 14-bus and 118-bus systems.
基金supported in part by the 2021 Graduate Research and Innovation Program of Jiangsu,China (No.KYCX21_0473)the China Scholarship Council (CSC) Program (No.202106710110)。
文摘This paper proposes a distribution locational marginal pricing(DLMP) based bi-level Stackelberg game framework between the internet service company(ISC) and distribution system operator(DSO) in the data center park. To minimize electricity costs, the ISC at the upper level dispatches the interactive workloads(IWs) across different data center buildings spatially and schedules the battery energy storage system temporally in response to DLMP. Photovoltaic generation and static var generation provide extra active and reactive power. At the lower level, DSO calculates the DLMP by minimizing the total electricity cost under the two-part tariff policy and ensures that the distribution network is uncongested and bus voltage is within the limit. The equilibrium solution is obtained by converting the bi-level optimization into a single-level mixed-integer second-order cone programming optimization using the strong duality theorem and the binary expansion method. Case studies verify that the proposed method benefits both the DSO and ISC while preserving the privacy of the ISC. By taking into account the uncertainties in IWs and photovoltaic generation, the flexibility of distribution networks is enhanced, which further facilitates the accommodation of more demand-side resources.
文摘An iterative method based on Shapley Value Cooperative Game Theory is proposed for the calculation of local marginal price (LMP) for each Distributed Generator (DG) bus on a network. The LMP value is determined for each DG on the basis of its contribution to reduce loss and emission reduction, which is assessed using the Shapley Value approach. The proposed approach enables the Distribution Company (DISCO) decision-maker to operate the network optimally in terms of loss and emission. The proposed method is implemented in the Taiwan Power Company distribution network 7 warnings consisting of 84 buses and 11 feeders in the MATLAB environment. The results show that the proposed approach allows DISCO to operate the network on the basis of its priority between the reduction of active power loss and emission in the network.
基金Supported by the National Basic Research Program of China(2012CB025904)Zhengzhou Shengda University of Economics,Business and Management(SD-YB2025085)。
文摘Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme.
基金supported by the National Natural Science Foundation of China(52007032)Basic Research Program of Jiangsu Province(BK20200385)National Key R&D Program of China(2022YFB2703500).
文摘Power system resilience procurement costs in N-k contingencies have gained more prominence as number of extreme events continues to increase.A chain rule is presented in this paper for extracting resilience procurement costs from a fully decomposed locational marginal price(LMP)model.First,power transfer distribution factor(PTDF)matrices with AC power flow(i.e.,AC-PTDF)are determined.AC-PTDF and AC-LODF(line outage distribution factor)equations are derived for N-k contingencies and a fully decomposed LMP model is developed where generation and transmission security components are established for specific contingencies.Furthermore,resilience procurement costs can be measured at different buses for the proposed security components.Impact of N-k contingencies on resilience procurement costs at specific buses can be determined as proposed security components will gain more insight for resilience procurement in power systems.The modified IEEE 6-bus and 118-bus systems are adopted to verify effectiveness of the proposed resilience procurement method.
文摘Salzburg is a beautiful city in Austria.It has old buildings,pretty streets and big mountains all around.The scenery is amazing!The famous movie The Sound of Music was filmed there.Many people visit Salzburg to see the locations from the movie.Some even do interviews there to ask people their feelings about the movie.One famous location from the movie is the Mirabell Gardens.The actors sang the song"Do-Re-Mi"there.The gardens have colorful flowers,statues and fountains.Salzburg is a fun and exciting place to visit and explore.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.52278415the National Key Research and Development Program of China under Grant No.2022YFC3801104+2 种基金Hebei Provincial Department of Education Project under Grant No.QN2025304the Innovation Fund Project of Hebei University of Engineering under Grant No.SJ2401002066the Sichuan Science and Technology Program under Grant No.2023YFS0407。
文摘The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.
文摘Preferential policies,efficient government,and a favorable geographical location...a multitude of factors make the Hainan FTP a promising land for businesses.SOON after the Hainan Free Trade Port(FTP)launched special customs operations at the end of 2025,private enterprises operating at its Yangpu Port began to benefit substantially from the favorable policies and surging growth momentum in the region.While riding on an ocean of opportunities opened by the FTP,local businesses are bringing the island to a new level of prosperity,and thriving together with it as a community of shared future.
