This paper presents a novel approach to dynamic pricing and distributed energy management in virtual power plant(VPP)networks using multi-agent reinforcement learning(MARL).As the energy landscape evolves towards grea...This paper presents a novel approach to dynamic pricing and distributed energy management in virtual power plant(VPP)networks using multi-agent reinforcement learning(MARL).As the energy landscape evolves towards greater decentralization and renewable integration,traditional optimization methods struggle to address the inherent complexities and uncertainties.Our proposed MARL framework enables adaptive,decentralized decision-making for both the distribution system operator and individual VPPs,optimizing economic efficiency while maintaining grid stability.We formulate the problem as a Markov decision process and develop a custom MARL algorithm that leverages actor-critic architectures and experience replay.Extensive simulations across diverse scenarios demonstrate that our approach consistently outperforms baseline methods,including Stackelberg game models and model predictive control,achieving an 18.73%reduction in costs and a 22.46%increase in VPP profits.The MARL framework shows particular strength in scenarios with high renewable energy penetration,where it improves system performance by 11.95%compared with traditional methods.Furthermore,our approach demonstrates superior adaptability to unexpected events and mis-predictions,highlighting its potential for real-world implementation.展开更多
By using ZHANG Qiao＇s method for identifying fuzzy words （1998）, the present paper makes a statistic analysis of fuzzy words appearing in about 43,000 words of 6 academic research articles in management science. A ...By using ZHANG Qiao＇s method for identifying fuzzy words （1998）, the present paper makes a statistic analysis of fuzzy words appearing in about 43,000 words of 6 academic research articles in management science. A distribution curve of fuzzy words in management research articles is drawn in accordance with the structures of the articles, and it is proved to be reasonable for tile discourse function of each section. Furthermore, the fuzzy words are divided into three categories and eleven sub-categories, including Category Ⅰ-fuzzy words, Category Ⅱ-fuzzy words＋non-fuzzy part / non-fuzzy part＋fuzzy words, Category Ⅲ-approximators＋fuzzy words. Distribution of fuzzy words varies in different sections of research articles in management science, because of different communicative purposes or discourse functions. Introduction section and Conclusion section have a higher occurrence rate of fuzzy words than Abstract section and Methodology and Data section.展开更多
Efficient data management in healthcare is essential for providing timely and accurate patient care, yet traditional partitioning methods in relational databases often struggle with the high volume, heterogeneity, and...Efficient data management in healthcare is essential for providing timely and accurate patient care, yet traditional partitioning methods in relational databases often struggle with the high volume, heterogeneity, and regulatory complexity of healthcare data. This research introduces a tailored partitioning strategy leveraging the MD5 hashing algorithm to enhance data insertion, query performance, and load balancing in healthcare systems. By applying a consistent hash function to patient IDs, our approach achieves uniform distribution of records across partitions, optimizing retrieval paths and reducing access latency while ensuring data integrity and compliance. We evaluated the method through experiments focusing on partitioning efficiency, scalability, and fault tolerance. The partitioning efficiency analysis compared our MD5-based approach with standard round-robin methods, measuring insertion times, query latency, and data distribution balance. Scalability tests assessed system performance across increasing dataset sizes and varying partition counts, while fault tolerance experiments examined data integrity and retrieval performance under simulated partition failures. The experimental results demonstrate that the MD5-based partitioning strategy significantly reduces query retrieval times by optimizing data access patterns, achieving up to X% better performance compared to round-robin methods. It also scales effectively with larger datasets, maintaining low latency and ensuring robust resilience under failure scenarios. This novel approach offers a scalable, efficient, and fault-tolerant solution for healthcare systems, facilitating faster clinical decision-making and improved patient care in complex data environments.展开更多
Decision support systems(DSS)based on physically based numerical models are standard tools used by water services and utilities.However,few DSS based on holistic approaches combining distributed hydrological,hydraulic...Decision support systems(DSS)based on physically based numerical models are standard tools used by water services and utilities.However,few DSS based on holistic approaches combining distributed hydrological,hydraulic,and hydrogeological models are operationally exploited.This holistic approach was adopted for the development of the AquaVar DSS,used for water resource management in the French Mediterranean Var watershed.The year 2019 marked the initial use of the DSS in its operational environment.Over the next 5 years,multiple hydrological events allowed to test the performance of the DSS.The results show that the tool is capable of simulating peak flows associated with two extreme rainfall events(storms Alex and Aline).For a moderate flood,the real-time functionality was able to simulate forecast discharges 26 h before the flood peak,with a maximum local error of 30%.Finally,simulations for the drought period 2022-2023 highlighted the essential need for DSS to evolve in line with changing climatic conditions,which give rise to unprecedented hydrological processes.The lessons learned from these first 5 years of AquaVar use under operational conditions are synthesized,addressing various topics such as DSS modularity,evolution,data positioning,technology,and governance.展开更多
The article investigates the optimal energy management(OEM)problem for microgrids.To figure out the problem in fixed time and alleviate communication load with limited resources,this article devises a novel fixed-time...The article investigates the optimal energy management(OEM)problem for microgrids.To figure out the problem in fixed time and alleviate communication load with limited resources,this article devises a novel fixed-time stability lemma and an event-triggered(ET)fixed-time distributed OEM approach.Using Lyapunov stability theory,the distributed approach has been proven to converge in fixed time and the upper bound on convergence time can be derived without dependence on the initial states.The dynamic ET method is raised to dynamically adjust the triggering threshold and reduce communication redundancy.In addition,Zeno behavior is avoided.Simulations are given to show the effectiveness and advantage of the designed distributed OEM method.展开更多
Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution...Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution and impacts of wild boars were examined using a questionnaire survey and spatial analysis.The results showed that:(1)The density of farmer settlements is low and most peasants’households are located on the forest edge.Due to large-scale labor migration,a high proportion of farmland(25.85%)has been abandoned and an even higher proportion of farmland(40.48%)has been returned to forest.(2)The probability of wild boar damage to peasant households was 67.96%.Yields of corn and sweet potato decreased by 24.87%and 28.24%,respectively,with a total economic loss of approximately 2,590,100 RMB/yr in the Wuqiaohe basin.Sixty-five percent of the affected cultivatedlands were located within approximately 150 m of the forest edges.(3)The wild boar damage coefficient was significantly and negatively correlated with the distance between the peasants’household and the forest edge,the density of the settlements,and the area of cultivated land.The wild boar damage coefficient shows a significant positive correlation with the area of farmland returned to forest.(4)The damage activity caused by wild boars began to occur7-8 years ago,and the destruction has been more frequently and seriously observed in the last 4-5 years.(5)We make suggestions for wild boar control and management measures including developing a compensation policy.The compensation standard is related to the land area returning from farmland to forests and the actual cultivated land area.展开更多
Uncontrolled harvesting of non-timber forest products （NTFPs） poses a serious risk of extermination to several of these species in Nigeria. Yet, there is a paucity of information on the distribution, population stat...Uncontrolled harvesting of non-timber forest products （NTFPs） poses a serious risk of extermination to several of these species in Nigeria. Yet, there is a paucity of information on the distribution, population status and sustainable management of NTFPs in most of the tropical lowland rainforests. We, therefore, assessed the population, distribution and threats to sustainable management of NTFPs within the tropical lowland rainforests of Omo and Shasha Forest Reserves, south western Nigeria. Data were obtained through inventory surveys on five top priority species including： bush mango （Irvingia gabonensis （Aubry-Lecomte ex O’Rorke） Baill）, African walnut （Tetracarpidium conophorum （Mull. Arg.） Hutch. ＆ Dalziel syn. Plukenetia conophora）, chew-stick （Massularia acuminata （G. Don） Bullock）, fever bark （Annickia chlorantha Setten ＆ P.J.Maas syn. Enantia chloranta） and bush pepper （Piper guineense Schumach. ＆ Thonn.）. Purposive and stratified random sampling techniques were used for the inventory. Each forest reserve was stratified into three, viz： less disturbed natural forest （for areas that have been rested for at least ten years）, recently disturbed natural forest （for areas that have suffered one form of human perturbation or the other in the last five years）, and plantation forest （for areas carrying forest plantation）. Data were collected from eighteen 10 m × 500 m belt transects located in the above strata. The species were generally fewer in both plantation and recently disturbed natural forest than the less disturbed natural forest, suggesting that forest disturbances （habitat modification） for other uses may have an effect on the occurrence and densities of the NTFPs. Exceptions to this trend were found for P. guineense and T. conophorum, which were fairly common in both plantation and recently disturbed natural forest. Among three tree NTFP species （i.e. I. gabonensis, M. acuminata and A. chlorantha）, only I. gabonensis showed a significant difference in overall DBH size classes for both reserves （t=？2.404; df =21; p=0.026）. Three tree NTFP species in both reserves further showed differences from the regular patterns of distribution of trees. The fairly regular reverse J-shaped size class distribution observed for M. acuminata in the study sites, however, suggests a recuperating population. In general, destructive harvesting of species, logging operations, low population size, narrow distribution ranges and habitat degradation are the major threats to the population of NTFPs in the study area. The implications of our findings for sustainable management of NTFPs in the study area are discussed and recommendations are made for a feasible approach towards enhancing the status of the species.展开更多
Since distribution sector is inherent into high amount of failures, distribution companies (DISCOs) are responsible of attaining an acceptable value for the reliability indices and otherwise they will face up to compl...Since distribution sector is inherent into high amount of failures, distribution companies (DISCOs) are responsible of attaining an acceptable value for the reliability indices and otherwise they will face up to complaints. So they are usually obligated by regulators to invest on reliability improvement of network. But this investment on reliability is usually from the DISCO’s viewpoint and is also irrespective of customer satisfaction level. In other words, customers are not at the same level of sensitivity to interruptions but DISCO improves the reliability of network without considering the differences in importance degree of loads and their level of reliability requirement. On the other hand DISCOs attempt to reduce their investment costs as much as possible. This paper introduces a novel approach in the field of joint switch placement that can reduce the switch cost from the perspective of asset management policies. To this end, two switch placement plannings in different types of strategies are performed to compare their results. Firstly as witch placement is performed based on reducing the total energy not supplied (ENS) of the system. Then by revising the strategy, a fuzzy switch placement is performed from the DISCO’s point of view which just considers the total ENS of load points most sensitive to interruptions known as important or critical loads. Furthermore, by meeting the related constraints, the reliability of low sensitive customers is disregarded. This is a load importance based planning which can result in switch cost reduction relative to the amount achieved in previous strategy and implies the management of risks associated with reliability and respective constraint. Fuzzy method and new switching mechanism in fuzzy environment of network are implemented to modeling and controlling the risks associated to ENS of critical loads and also the ENS of system.展开更多
Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction...Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction, and urban management, etc. This article first describes the growth of urban population, the scale and the input of urban construction, and then analyzes the financial revenue and expenditure, and at last argues for the necessity of urban management, and puts forward the research content of urban management.展开更多
This paper presents a digital rights management model, which considers the integrated factors including legality, communication security, integrity of the content, and trading fairness. The architecture of the model, ...This paper presents a digital rights management model, which considers the integrated factors including legality, communication security, integrity of the content, and trading fairness. The architecture of the model, the necessary protocol for the copyright control and content distribution, the authentication mechanism which offer consumption registration for content fair distribution, of the model are all provided. The scheme also provides distribution and evidence for using the copyright of digital content fairly and effectively. Finally, analysis shows the proposed model has both high security and good performance.展开更多
The effective disposal of daily city infrastructure cases is an important issue for urban management. To more effectively utilize a large amount of historical cases data collected and accumulated in the urban grid man...The effective disposal of daily city infrastructure cases is an important issue for urban management. To more effectively utilize a large amount of historical cases data collected and accumulated in the urban grid management system, and to analyze their spatial distribution pattern information for city managers, this study used the comparative kernel density analysis method in two types of cases (i.e. power facilities and traffic guardrail) in Xicheng District, Beijing for the year 2016 and 2017. This research analyzes them at different scales (300 m, 600 m, 1,200 m), and the experiment results show that the method of comparative kernel density analysis is able to provide an intuitively spatial visualization distribution analysis of city infrastructure related cases. The quantitative information of spatial agglomeration degree is helpful for city managers making decision.展开更多
World energy consumption increased by 56 percent, from 524 quadrillion Btu in 2010 to 820 quadrillion Btu in 2040. The increased demand in energy consumption is fulfilled by different renewable and non-renewable sourc...World energy consumption increased by 56 percent, from 524 quadrillion Btu in 2010 to 820 quadrillion Btu in 2040. The increased demand in energy consumption is fulfilled by different renewable and non-renewable sources such as petroleum, natural gas, electricity, nuclear etc. Natural gas is one of the most important sources of energy. SNGPL has been managing a 94,263 km long gas pipelines network covering approximately the northern part of Pakistan. In this paper we have presented the use of condition based maintenance (CBM) management techniques with a?geographical information system (GIS) for asset management of a gas distribution network of?SNGPL. The continuous monitoring and updating of asset data reveal where the assets are located and which needs maintenance or which lies in critical condition. The system helps to save time and reduce visits to the sites and labour reduction.展开更多
Based on the existed equipment (the power line carrier, optic fiber, twisted pair and wireless apparatus) being used to the same route in the current communication net of distribution management system (DMS), this pap...Based on the existed equipment (the power line carrier, optic fiber, twisted pair and wireless apparatus) being used to the same route in the current communication net of distribution management system (DMS), this paper presents a new kind of communication monitor DMS, which provides a communication monitoring interface and then by DMS, data transfer problem from field terminal unit to junction center station can be solved and the communication channels can also be supervised. At the same time, synthetically using computer communication, internet technology and database technology, this system can realize the real time monitoring and fault locating in the communication network.展开更多
The distribution of resources is the basis of safety management.Based on thesystematic analysis of a resource distribution system affecting the level of safety,the bestdistribution proportion between safety activities...The distribution of resources is the basis of safety management.Based on thesystematic analysis of a resource distribution system affecting the level of safety,the bestdistribution proportion between safety activities and production and best resources distributionproportion among the various links of security activities are presented.Moreover,itis stated that the distribution of resources law needs to be researched deeply in practicalwork to achieve optimization of safety management practice.展开更多
A de-centralised load management technique exploiting the flexibility in the charging of Electric Vehicles (EVs) is presented. Two charging regimes are assumed. The Controlled Charging Regime (CCR) between 16:30 hours...A de-centralised load management technique exploiting the flexibility in the charging of Electric Vehicles (EVs) is presented. Two charging regimes are assumed. The Controlled Charging Regime (CCR) between 16:30 hours and 06:00 hours of the next day and the Uncontrolled Charging Regime (UCR) between 06:00 hours and 16:30 hours of the same day. During the CCR, the charging of EVs is coordinated and controlled by means of a wireless two-way communication link between EV Smart Charge Controllers (EVSCCs) at EV owners’ premises and the EV Load Controller (EVLC) at the local LV distribution substation. The EVLC sorts the EVs batteries in ascending order of their states of charge (SoC) and sends command signals for charging to as many EVs as the transformer could allow at that interval based on the condition of the transformer as analysed by the Distribution Transformer Monitor (DTM). A real and typical urban LV area distribution network in Great Britain (GB) is used as the case study. The technique is applied on</span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">the LV area when its transformer is carrying the future load demand of the area on a typical winter weekday in the year 2050. To achieve the load management, load demand of the LV area network is decomposed into Non-EV <span>load and EV load. The load on the transformer is managed by varying the EV load in an optimisation objective function which maximises the capacity uti</span>lisation of the transformer subject to operational constraints and non-disruption of daily trips of EV owners. Results show that with the proposed load management technique, LV distribution networks could accommodate high uptake of EVs without compromising the useful normal life expectancy of distribution transformers before the need for capacity reinforcement.展开更多
In this paper, we conduct analysis on the development and optimization of financial management and the benefit distribution pattern from perspective of multi-dimensional cooperation enterprise. Financial management is...In this paper, we conduct analysis on the development and optimization of financial management and the benefit distribution pattern from perspective of multi-dimensional cooperation enterprise. Financial management is the whole process of capital operation of the modern enterprise decision-making, planning and control of the management activities. Financial management is an important part of enterprise management, enterprise＇ s sustainable development requires the financial management in the central position in the management of the enterprise, according to the present our country enterprise financial management of a series of problems, in this paper, starting from the connotation of the enterprise financial management, we analyses the center of the enterprise financial management status and further puts forward some countermeasures to solve from the perspectives of the multi-dimensional cooperation which obtains the satisfactory performance.展开更多
The reliability of distribution network is related to the power consumption of a large number of users in the region. At present, there are still problems in improving the reliability of distribution network in remote...The reliability of distribution network is related to the power consumption of a large number of users in the region. At present, there are still problems in improving the reliability of distribution network in remote areas. This paper will put forward some suggestions and feasible measures to improve the reliability of distribution network in remote areas.展开更多
The safety management of distribution network in the operation process is of great significance to ensure the stability of the whole power system. Combined with maintenance strategies and application requirements, com...The safety management of distribution network in the operation process is of great significance to ensure the stability of the whole power system. Combined with maintenance strategies and application requirements, comprehensive management efficiency should be maintained, grid failure rate should be reduced, and timeliness of comprehensive supervision of chemical distribution network maintenance should be improved. In the process of application of network operation and management technology, effective technological transformation must be strengthened, problems among different components should be analyzed flexibly, and optimization of the whole system should be strengthened in order to further realize stable operation of the distribution network.展开更多
In recent years, China's social economy and the rapid development of science and technology, which has promoted the rapid development of various industries, at the same time, excessive waste emissions and energy s...In recent years, China's social economy and the rapid development of science and technology, which has promoted the rapid development of various industries, at the same time, excessive waste emissions and energy shortage has gradually emerged, so that the normal operation of the ecological environment has been greatly affected. Based on the increasing consumption of water resources, it has to adopt advanced science and technology to purify sewage treatment, and then the second use, in order to save water resources. In the sewage treatment plant, the most indispensable basic equipment is mechanical and electrical equipment, which directly affects the normal operation of the water treatment plant. Generally speaking, mechanical and electrical equipment includes electrical control and power distribution equipment. This article mainly introduces and analyzes the daily management of electrical control and power distribution equipment in the sewage treatment plant.展开更多
基金supported by the Science and Technology Project of State Grid Sichuan Electric Power Company Chengdu Power Supply Company under Grant No.521904240005.
文摘This paper presents a novel approach to dynamic pricing and distributed energy management in virtual power plant(VPP)networks using multi-agent reinforcement learning(MARL).As the energy landscape evolves towards greater decentralization and renewable integration,traditional optimization methods struggle to address the inherent complexities and uncertainties.Our proposed MARL framework enables adaptive,decentralized decision-making for both the distribution system operator and individual VPPs,optimizing economic efficiency while maintaining grid stability.We formulate the problem as a Markov decision process and develop a custom MARL algorithm that leverages actor-critic architectures and experience replay.Extensive simulations across diverse scenarios demonstrate that our approach consistently outperforms baseline methods,including Stackelberg game models and model predictive control,achieving an 18.73%reduction in costs and a 22.46%increase in VPP profits.The MARL framework shows particular strength in scenarios with high renewable energy penetration,where it improves system performance by 11.95%compared with traditional methods.Furthermore,our approach demonstrates superior adaptability to unexpected events and mis-predictions,highlighting its potential for real-world implementation.
文摘By using ZHANG Qiao＇s method for identifying fuzzy words （1998）, the present paper makes a statistic analysis of fuzzy words appearing in about 43,000 words of 6 academic research articles in management science. A distribution curve of fuzzy words in management research articles is drawn in accordance with the structures of the articles, and it is proved to be reasonable for tile discourse function of each section. Furthermore, the fuzzy words are divided into three categories and eleven sub-categories, including Category Ⅰ-fuzzy words, Category Ⅱ-fuzzy words＋non-fuzzy part / non-fuzzy part＋fuzzy words, Category Ⅲ-approximators＋fuzzy words. Distribution of fuzzy words varies in different sections of research articles in management science, because of different communicative purposes or discourse functions. Introduction section and Conclusion section have a higher occurrence rate of fuzzy words than Abstract section and Methodology and Data section.
文摘Efficient data management in healthcare is essential for providing timely and accurate patient care, yet traditional partitioning methods in relational databases often struggle with the high volume, heterogeneity, and regulatory complexity of healthcare data. This research introduces a tailored partitioning strategy leveraging the MD5 hashing algorithm to enhance data insertion, query performance, and load balancing in healthcare systems. By applying a consistent hash function to patient IDs, our approach achieves uniform distribution of records across partitions, optimizing retrieval paths and reducing access latency while ensuring data integrity and compliance. We evaluated the method through experiments focusing on partitioning efficiency, scalability, and fault tolerance. The partitioning efficiency analysis compared our MD5-based approach with standard round-robin methods, measuring insertion times, query latency, and data distribution balance. Scalability tests assessed system performance across increasing dataset sizes and varying partition counts, while fault tolerance experiments examined data integrity and retrieval performance under simulated partition failures. The experimental results demonstrate that the MD5-based partitioning strategy significantly reduces query retrieval times by optimizing data access patterns, achieving up to X% better performance compared to round-robin methods. It also scales effectively with larger datasets, maintaining low latency and ensuring robust resilience under failure scenarios. This novel approach offers a scalable, efficient, and fault-tolerant solution for healthcare systems, facilitating faster clinical decision-making and improved patient care in complex data environments.
文摘Decision support systems(DSS)based on physically based numerical models are standard tools used by water services and utilities.However,few DSS based on holistic approaches combining distributed hydrological,hydraulic,and hydrogeological models are operationally exploited.This holistic approach was adopted for the development of the AquaVar DSS,used for water resource management in the French Mediterranean Var watershed.The year 2019 marked the initial use of the DSS in its operational environment.Over the next 5 years,multiple hydrological events allowed to test the performance of the DSS.The results show that the tool is capable of simulating peak flows associated with two extreme rainfall events(storms Alex and Aline).For a moderate flood,the real-time functionality was able to simulate forecast discharges 26 h before the flood peak,with a maximum local error of 30%.Finally,simulations for the drought period 2022-2023 highlighted the essential need for DSS to evolve in line with changing climatic conditions,which give rise to unprecedented hydrological processes.The lessons learned from these first 5 years of AquaVar use under operational conditions are synthesized,addressing various topics such as DSS modularity,evolution,data positioning,technology,and governance.
基金supported by the National Natural Science Foundation of China(62473316,62073269)the Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX0963)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515011220)Aeronautical Science Foundation of China(2020Z034053002)。
文摘The article investigates the optimal energy management(OEM)problem for microgrids.To figure out the problem in fixed time and alleviate communication load with limited resources,this article devises a novel fixed-time stability lemma and an event-triggered(ET)fixed-time distributed OEM approach.Using Lyapunov stability theory,the distributed approach has been proven to converge in fixed time and the upper bound on convergence time can be derived without dependence on the initial states.The dynamic ET method is raised to dynamically adjust the triggering threshold and reduce communication redundancy.In addition,Zeno behavior is avoided.Simulations are given to show the effectiveness and advantage of the designed distributed OEM method.
基金supported by the 135 strategic program of the institute of mountain hazards and environment, CAS (NO. SDS-135-1703)national natural science foundation of China (No. 41401664)
文摘Economic losses caused by wild boars(Sus scrofa)continue to increase in the Three Gorges Reservoir Area.We selected 206 farmers in Wuqiaohe Basin as survey respondents using random stratified sampling.The distribution and impacts of wild boars were examined using a questionnaire survey and spatial analysis.The results showed that:(1)The density of farmer settlements is low and most peasants’households are located on the forest edge.Due to large-scale labor migration,a high proportion of farmland(25.85%)has been abandoned and an even higher proportion of farmland(40.48%)has been returned to forest.(2)The probability of wild boar damage to peasant households was 67.96%.Yields of corn and sweet potato decreased by 24.87%and 28.24%,respectively,with a total economic loss of approximately 2,590,100 RMB/yr in the Wuqiaohe basin.Sixty-five percent of the affected cultivatedlands were located within approximately 150 m of the forest edges.(3)The wild boar damage coefficient was significantly and negatively correlated with the distance between the peasants’household and the forest edge,the density of the settlements,and the area of cultivated land.The wild boar damage coefficient shows a significant positive correlation with the area of farmland returned to forest.(4)The damage activity caused by wild boars began to occur7-8 years ago,and the destruction has been more frequently and seriously observed in the last 4-5 years.(5)We make suggestions for wild boar control and management measures including developing a compensation policy.The compensation standard is related to the land area returning from farmland to forests and the actual cultivated land area.
文摘Uncontrolled harvesting of non-timber forest products （NTFPs） poses a serious risk of extermination to several of these species in Nigeria. Yet, there is a paucity of information on the distribution, population status and sustainable management of NTFPs in most of the tropical lowland rainforests. We, therefore, assessed the population, distribution and threats to sustainable management of NTFPs within the tropical lowland rainforests of Omo and Shasha Forest Reserves, south western Nigeria. Data were obtained through inventory surveys on five top priority species including： bush mango （Irvingia gabonensis （Aubry-Lecomte ex O’Rorke） Baill）, African walnut （Tetracarpidium conophorum （Mull. Arg.） Hutch. ＆ Dalziel syn. Plukenetia conophora）, chew-stick （Massularia acuminata （G. Don） Bullock）, fever bark （Annickia chlorantha Setten ＆ P.J.Maas syn. Enantia chloranta） and bush pepper （Piper guineense Schumach. ＆ Thonn.）. Purposive and stratified random sampling techniques were used for the inventory. Each forest reserve was stratified into three, viz： less disturbed natural forest （for areas that have been rested for at least ten years）, recently disturbed natural forest （for areas that have suffered one form of human perturbation or the other in the last five years）, and plantation forest （for areas carrying forest plantation）. Data were collected from eighteen 10 m × 500 m belt transects located in the above strata. The species were generally fewer in both plantation and recently disturbed natural forest than the less disturbed natural forest, suggesting that forest disturbances （habitat modification） for other uses may have an effect on the occurrence and densities of the NTFPs. Exceptions to this trend were found for P. guineense and T. conophorum, which were fairly common in both plantation and recently disturbed natural forest. Among three tree NTFP species （i.e. I. gabonensis, M. acuminata and A. chlorantha）, only I. gabonensis showed a significant difference in overall DBH size classes for both reserves （t=？2.404; df =21; p=0.026）. Three tree NTFP species in both reserves further showed differences from the regular patterns of distribution of trees. The fairly regular reverse J-shaped size class distribution observed for M. acuminata in the study sites, however, suggests a recuperating population. In general, destructive harvesting of species, logging operations, low population size, narrow distribution ranges and habitat degradation are the major threats to the population of NTFPs in the study area. The implications of our findings for sustainable management of NTFPs in the study area are discussed and recommendations are made for a feasible approach towards enhancing the status of the species.
文摘Since distribution sector is inherent into high amount of failures, distribution companies (DISCOs) are responsible of attaining an acceptable value for the reliability indices and otherwise they will face up to complaints. So they are usually obligated by regulators to invest on reliability improvement of network. But this investment on reliability is usually from the DISCO’s viewpoint and is also irrespective of customer satisfaction level. In other words, customers are not at the same level of sensitivity to interruptions but DISCO improves the reliability of network without considering the differences in importance degree of loads and their level of reliability requirement. On the other hand DISCOs attempt to reduce their investment costs as much as possible. This paper introduces a novel approach in the field of joint switch placement that can reduce the switch cost from the perspective of asset management policies. To this end, two switch placement plannings in different types of strategies are performed to compare their results. Firstly as witch placement is performed based on reducing the total energy not supplied (ENS) of the system. Then by revising the strategy, a fuzzy switch placement is performed from the DISCO’s point of view which just considers the total ENS of load points most sensitive to interruptions known as important or critical loads. Furthermore, by meeting the related constraints, the reliability of low sensitive customers is disregarded. This is a load importance based planning which can result in switch cost reduction relative to the amount achieved in previous strategy and implies the management of risks associated with reliability and respective constraint. Fuzzy method and new switching mechanism in fuzzy environment of network are implemented to modeling and controlling the risks associated to ENS of critical loads and also the ENS of system.
文摘Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction, and urban management, etc. This article first describes the growth of urban population, the scale and the input of urban construction, and then analyzes the financial revenue and expenditure, and at last argues for the necessity of urban management, and puts forward the research content of urban management.
基金Supported by Scientific Research Common Programof Beijing Municipal Commission of Education( KM200610772008)the Graduate Innovation Fund of Xidian University(05001)
文摘This paper presents a digital rights management model, which considers the integrated factors including legality, communication security, integrity of the content, and trading fairness. The architecture of the model, the necessary protocol for the copyright control and content distribution, the authentication mechanism which offer consumption registration for content fair distribution, of the model are all provided. The scheme also provides distribution and evidence for using the copyright of digital content fairly and effectively. Finally, analysis shows the proposed model has both high security and good performance.
文摘The effective disposal of daily city infrastructure cases is an important issue for urban management. To more effectively utilize a large amount of historical cases data collected and accumulated in the urban grid management system, and to analyze their spatial distribution pattern information for city managers, this study used the comparative kernel density analysis method in two types of cases (i.e. power facilities and traffic guardrail) in Xicheng District, Beijing for the year 2016 and 2017. This research analyzes them at different scales (300 m, 600 m, 1,200 m), and the experiment results show that the method of comparative kernel density analysis is able to provide an intuitively spatial visualization distribution analysis of city infrastructure related cases. The quantitative information of spatial agglomeration degree is helpful for city managers making decision.
文摘World energy consumption increased by 56 percent, from 524 quadrillion Btu in 2010 to 820 quadrillion Btu in 2040. The increased demand in energy consumption is fulfilled by different renewable and non-renewable sources such as petroleum, natural gas, electricity, nuclear etc. Natural gas is one of the most important sources of energy. SNGPL has been managing a 94,263 km long gas pipelines network covering approximately the northern part of Pakistan. In this paper we have presented the use of condition based maintenance (CBM) management techniques with a?geographical information system (GIS) for asset management of a gas distribution network of?SNGPL. The continuous monitoring and updating of asset data reveal where the assets are located and which needs maintenance or which lies in critical condition. The system helps to save time and reduce visits to the sites and labour reduction.
文摘Based on the existed equipment (the power line carrier, optic fiber, twisted pair and wireless apparatus) being used to the same route in the current communication net of distribution management system (DMS), this paper presents a new kind of communication monitor DMS, which provides a communication monitoring interface and then by DMS, data transfer problem from field terminal unit to junction center station can be solved and the communication channels can also be supervised. At the same time, synthetically using computer communication, internet technology and database technology, this system can realize the real time monitoring and fault locating in the communication network.
文摘The distribution of resources is the basis of safety management.Based on thesystematic analysis of a resource distribution system affecting the level of safety,the bestdistribution proportion between safety activities and production and best resources distributionproportion among the various links of security activities are presented.Moreover,itis stated that the distribution of resources law needs to be researched deeply in practicalwork to achieve optimization of safety management practice.
文摘A de-centralised load management technique exploiting the flexibility in the charging of Electric Vehicles (EVs) is presented. Two charging regimes are assumed. The Controlled Charging Regime (CCR) between 16:30 hours and 06:00 hours of the next day and the Uncontrolled Charging Regime (UCR) between 06:00 hours and 16:30 hours of the same day. During the CCR, the charging of EVs is coordinated and controlled by means of a wireless two-way communication link between EV Smart Charge Controllers (EVSCCs) at EV owners’ premises and the EV Load Controller (EVLC) at the local LV distribution substation. The EVLC sorts the EVs batteries in ascending order of their states of charge (SoC) and sends command signals for charging to as many EVs as the transformer could allow at that interval based on the condition of the transformer as analysed by the Distribution Transformer Monitor (DTM). A real and typical urban LV area distribution network in Great Britain (GB) is used as the case study. The technique is applied on</span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">the LV area when its transformer is carrying the future load demand of the area on a typical winter weekday in the year 2050. To achieve the load management, load demand of the LV area network is decomposed into Non-EV <span>load and EV load. The load on the transformer is managed by varying the EV load in an optimisation objective function which maximises the capacity uti</span>lisation of the transformer subject to operational constraints and non-disruption of daily trips of EV owners. Results show that with the proposed load management technique, LV distribution networks could accommodate high uptake of EVs without compromising the useful normal life expectancy of distribution transformers before the need for capacity reinforcement.
文摘In this paper, we conduct analysis on the development and optimization of financial management and the benefit distribution pattern from perspective of multi-dimensional cooperation enterprise. Financial management is the whole process of capital operation of the modern enterprise decision-making, planning and control of the management activities. Financial management is an important part of enterprise management, enterprise＇ s sustainable development requires the financial management in the central position in the management of the enterprise, according to the present our country enterprise financial management of a series of problems, in this paper, starting from the connotation of the enterprise financial management, we analyses the center of the enterprise financial management status and further puts forward some countermeasures to solve from the perspectives of the multi-dimensional cooperation which obtains the satisfactory performance.
文摘The reliability of distribution network is related to the power consumption of a large number of users in the region. At present, there are still problems in improving the reliability of distribution network in remote areas. This paper will put forward some suggestions and feasible measures to improve the reliability of distribution network in remote areas.
文摘The safety management of distribution network in the operation process is of great significance to ensure the stability of the whole power system. Combined with maintenance strategies and application requirements, comprehensive management efficiency should be maintained, grid failure rate should be reduced, and timeliness of comprehensive supervision of chemical distribution network maintenance should be improved. In the process of application of network operation and management technology, effective technological transformation must be strengthened, problems among different components should be analyzed flexibly, and optimization of the whole system should be strengthened in order to further realize stable operation of the distribution network.
文摘In recent years, China's social economy and the rapid development of science and technology, which has promoted the rapid development of various industries, at the same time, excessive waste emissions and energy shortage has gradually emerged, so that the normal operation of the ecological environment has been greatly affected. Based on the increasing consumption of water resources, it has to adopt advanced science and technology to purify sewage treatment, and then the second use, in order to save water resources. In the sewage treatment plant, the most indispensable basic equipment is mechanical and electrical equipment, which directly affects the normal operation of the water treatment plant. Generally speaking, mechanical and electrical equipment includes electrical control and power distribution equipment. This article mainly introduces and analyzes the daily management of electrical control and power distribution equipment in the sewage treatment plant.
