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
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
OBJECTIVE:To propose an automatic acupuncture robot system for performing acupuncture operations.METHODS:The acupuncture robot system consists of three components:automatic acupoint localization,acupuncture manipulati...OBJECTIVE:To propose an automatic acupuncture robot system for performing acupuncture operations.METHODS:The acupuncture robot system consists of three components:automatic acupoint localization,acupuncture manipulations,and De Qi sensation detection.The OptiTrack motion capture system is used to locate acupoints,which are then translated into coordinates in the robot control system.A flexible collaborative robot with an intelligent gripper is then used to perform acupuncture manipulations with high precision.In addition,a De Qi sensation detection system is proposed to evaluate the effect of acupuncture.To verify the stability of the designed acupuncture robot,acupoints'coordinates localized by the acupuncture robot are compared with the Gold Standard labeled by a professional acupuncturist using significant level tests.RESULTS:Through repeated experiments for eight acupoints,the acupuncture robot achieved a positioning error within 3.3 mm,which is within the allowable range of needle extraction and acupoint insertion.During needle insertion,the robot arm followed the prescribed trajectory with a mean deviation distance of 0.02 mm and a deviation angle of less than 0.15°.The results of the lifting thrusting operation in the Xingzhen process show that the mean acupuncture depth error of the designed acupuncture robot is approximately 2 mm,which is within the recommended depth range for the Xingzhen operation.In addition,the average detection accuracy of the De Qi keywords is 94.52%,which meets the requirements of acupuncture effect testing for different dialects.CONCLUSION:The proposed acupuncture robot system streamlines the acupuncture process,increases efficiency,and reduces practitioner fatigue,while also allowing for the quantification of acupuncture manipulations and evaluation of therapeutic effects.The development of an acupuncture robot system has the potential to revolutionize low back pain treatment and improve patient outcomes.展开更多
This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 2:Rat.This standard was released by the China Associat...This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 2:Rat.This standard was released by the China Association of Acupuncture and Moxibustion on May 15,2020,implemented on October 31,2020,and published by Standards Press of China.The standard was drafted by the Institute of Acupuncture and Moxibustion,China Academy of Chinese Medical Sciences,and the Nanjing University of Chinese Medicine.Principal draftsmen:Xiang-hong JING and Xing-bang HUA.Participating draftsmen:Wan-Zhu BAI,Bin XU,Dong-sheng XU,Yi GUO,Tie-ming MA,Xin-jun WANG,and Sheng-feng LU.展开更多
we critically review the authors’perspective and analyze the relevance of the results obtained in the original article of clinical research by Liu et al.We consider that additional factors associated with colon cance...we critically review the authors’perspective and analyze the relevance of the results obtained in the original article of clinical research by Liu et al.We consider that additional factors associated with colon cancer progression have recently been described in extensive clinical research,and should be included in this analysis to achieve a more accurate prognosis.These factors include inflammation,gut microbiota composition,immune status and nutritional balance,as they influence the post-surgical survival profile of patients with stage II colorectal cancer.We also address the clinical implementation and limitations of these analyses.Evaluation of the patient´s entire context is essential for selection of the most appropriate therapy.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 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.
基金Modernization of Traditional Chinese Medicine Project of National Key R&D Program of China:The construction of the theoretical system of Traditional Chinese Medicine nonpharmacological therapy based on body surface stimulation(2023YFC3502704)Sichuan Provincial Science and Technology Program Project:Research and Development of Chinese Medicine Intelligent Tongue Diagnosis Equipment for Digestive System Chinese Medicine Advantageous Diseases(2023YFS0327)+2 种基金Research and Development of Chinese Medicine Intelligent Detection System for Intestinal Functions(2024YFFK0044)Research and Application of Chinese Medicine Diagnosis and Treatment Program for Herpes Zoster Treated by Shu Pai Fire Acupuncture(2024YFFK0089)Major Research and Development Project of The China Academy of Chinese Medical Sciences Innovation:Construction and application of the theoretical research mode of Traditional Chinese Medicine diagnosis and treatment of modern diseases(CI2021A00104)。
文摘OBJECTIVE:To propose an automatic acupuncture robot system for performing acupuncture operations.METHODS:The acupuncture robot system consists of three components:automatic acupoint localization,acupuncture manipulations,and De Qi sensation detection.The OptiTrack motion capture system is used to locate acupoints,which are then translated into coordinates in the robot control system.A flexible collaborative robot with an intelligent gripper is then used to perform acupuncture manipulations with high precision.In addition,a De Qi sensation detection system is proposed to evaluate the effect of acupuncture.To verify the stability of the designed acupuncture robot,acupoints'coordinates localized by the acupuncture robot are compared with the Gold Standard labeled by a professional acupuncturist using significant level tests.RESULTS:Through repeated experiments for eight acupoints,the acupuncture robot achieved a positioning error within 3.3 mm,which is within the allowable range of needle extraction and acupoint insertion.During needle insertion,the robot arm followed the prescribed trajectory with a mean deviation distance of 0.02 mm and a deviation angle of less than 0.15°.The results of the lifting thrusting operation in the Xingzhen process show that the mean acupuncture depth error of the designed acupuncture robot is approximately 2 mm,which is within the recommended depth range for the Xingzhen operation.In addition,the average detection accuracy of the De Qi keywords is 94.52%,which meets the requirements of acupuncture effect testing for different dialects.CONCLUSION:The proposed acupuncture robot system streamlines the acupuncture process,increases efficiency,and reduces practitioner fatigue,while also allowing for the quantification of acupuncture manipulations and evaluation of therapeutic effects.The development of an acupuncture robot system has the potential to revolutionize low back pain treatment and improve patient outcomes.
文摘This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 2:Rat.This standard was released by the China Association of Acupuncture and Moxibustion on May 15,2020,implemented on October 31,2020,and published by Standards Press of China.The standard was drafted by the Institute of Acupuncture and Moxibustion,China Academy of Chinese Medical Sciences,and the Nanjing University of Chinese Medicine.Principal draftsmen:Xiang-hong JING and Xing-bang HUA.Participating draftsmen:Wan-Zhu BAI,Bin XU,Dong-sheng XU,Yi GUO,Tie-ming MA,Xin-jun WANG,and Sheng-feng LU.
基金Supported by Consejo Nacional de Investigaciones Científicas y Técnicas,No.PIP11220200103061COAgencia Nacional de promoción Científica y Tecnológica,No.PICT-2020-SERIEA-03440Universidad Nacional del Sur,No.PGI 24/B303 and No.PGI 24/ZB01.
文摘we critically review the authors’perspective and analyze the relevance of the results obtained in the original article of clinical research by Liu et al.We consider that additional factors associated with colon cancer progression have recently been described in extensive clinical research,and should be included in this analysis to achieve a more accurate prognosis.These factors include inflammation,gut microbiota composition,immune status and nutritional balance,as they influence the post-surgical survival profile of patients with stage II colorectal cancer.We also address the clinical implementation and limitations of these analyses.Evaluation of the patient´s entire context is essential for selection of the most appropriate therapy.
