The economic management of colleges and universities has always been a topic of great concern to China’s educational career,therefore,this paper will firstly make the necessary analysis of the current implementation ...The economic management of colleges and universities has always been a topic of great concern to China’s educational career,therefore,this paper will firstly make the necessary analysis of the current implementation of the economic management of colleges and universities in China,and then the reasons for the problems of economic management of colleges and universities in China is realized a detailed investigation,and finally,the economic management of colleges and universities based on capital and cost management optimization strategy is made a full discussion,looking forward to providing the necessary guidance for researchers in this field.展开更多
At present, with the continuous progress of the times, China's social and economic level has been significantly improved. In order to improve the quality of life of our people, the civil aviation industry has carr...At present, with the continuous progress of the times, China's social and economic level has been significantly improved. In order to improve the quality of life of our people, the civil aviation industry has carried out the corresponding optimization of aircraft maintenance work. In this regard, this paper analyzes and studies some problems existing in aircraft maintenance in China's civil aviation industry at present, and in order to effectively improve the overall maintenance quality and management level of the aircraft and promote the development of the civil aviation industry, puts forward corresponding optimization suggestions and maintenance measures.展开更多
The current trends in forestry in Europe include the increased use of continuous cover forestry(CCF)and the increased availability of tree-level forest inventory data.Accordingly,recent literature suggests methodologi...The current trends in forestry in Europe include the increased use of continuous cover forestry(CCF)and the increased availability of tree-level forest inventory data.Accordingly,recent literature suggests methodologies for optimizing the harvest decisions at the tree level.Using tree-level optimization for all trees of the stand is computationally demanding.This study proposed a two-level optimization method for CCF where the harvest prescriptions are optimized at the tree level for only a part of the trees or the first cuttings.The higher-level algorithm optimizes the cutting years and the harvest rates of those diameter classes for which tree-level optimization is not used.The lower-level algorithm allocates the individually optimized trees to different cutting events.The most detailed problem formulations,employing much tree-level optimization,resulted in the highest net present value and longest optimization time.However,restricting tree-level optimization to the largest trees and first cuttings did not significantly alter the time,intensity,or type of first cutting.Computing times could also be shortened by applying accumulated knowledge from previous optimizations,implementing learning aspects in heuristic search,and optimizing the search algorithms for short computing time and good-quality solutions.展开更多
Small municipal projects,constrained by resources and extensive management models,commonly face issues of delayed progress and cost overruns.This study uses a road renovation project in a city as an empirical case.By ...Small municipal projects,constrained by resources and extensive management models,commonly face issues of delayed progress and cost overruns.This study uses a road renovation project in a city as an empirical case.By integrating BIM collaborative platforms with real-time IoT monitoring systems,it achieves construction conflict prediction and dynamic resource allocation.Combining rolling planning methods and risk probability models,a“forecast-adaptation”dual-mode management framework is formed.After implementation,the total duration was shortened by 15%,the rework rate decreased by 20%,and inter-departmental communication efficiency improved by 30%.The case validates the effectiveness of digital tools and dynamic mechanisms working together to optimize,aligning with the requirements for refined control outlined in the“Construction Engineering Quantity List Pricing Standard”(GB/T50500-2024).It provides a replicable progress management paradigm for similar projects.展开更多
With the advancement of globalization and information technology,the financial sharing mode has gradually emerged as a crucial means for enterprises to optimize their financial management.Particularly within the conte...With the advancement of globalization and information technology,the financial sharing mode has gradually emerged as a crucial means for enterprises to optimize their financial management.Particularly within the context of economic globalization,informatization,and digital transformation,enterprises find themselves navigating a rapidly evolving market environment by intensifying competition.To enhance efficiency and competitiveness,many enterprises have embraced the financial sharing model to streamline financial management processes,curtail costs,and bolster the execution of corporate strategies.This article aims to dissect the definition and essence of the financial sharing model and its significance in the realm of enterprise financial management.Drawing upon this analysis and aligning with the needs of enterprise financial management,the article proposes ideas for optimizing management practices,aspiring to foster reform and innovation in enterprise financial management while enhancing its level of financial management and ability to respond to financial risks.This contribution seeks to provide valuable insights for practitioners in the field.展开更多
With the improvement of social and economic development level, China's construction industry is also developing continuously. Therefore, many new problems have emerged in its construction site management. These pr...With the improvement of social and economic development level, China's construction industry is also developing continuously. Therefore, many new problems have emerged in its construction site management. These problems will seriously affect the smooth implementation of the whole construction project. In addition, they may lead to personal safety risks. Therefore,It is necessary to optimize these construction site management. We should fully consider all links in the construction process and analyze them comprehensively, so as to continuously promote the smooth implementation of construction projects in our country.Next, the article discusses the optimization strategy of construction site management.展开更多
With the objective of reducing the flight cost and the amount of polluting emissions released in the atmosphere, a new optimization algorithm considering the climb, cruise and descent phases is presented for the refer...With the objective of reducing the flight cost and the amount of polluting emissions released in the atmosphere, a new optimization algorithm considering the climb, cruise and descent phases is presented for the reference vertical flight trajectory. The selection of the reference vertical navigation speeds and altitudes was solved as a discrete combinatory problem by means of a graphtree passing through nodes using the beam search optimization technique. To achieve a compromise between the execution time and the algorithm＇s ability to find the global optimal solution, a heuristic methodology introducing a parameter called ‘‘optimism coefficient was used in order to estimate the trajectory＇s flight cost at every node. The optimal trajectory cost obtained with the developed algorithm was compared with the cost of the optimal trajectory provided by a commercial flight management system（FMS）. The global optimal solution was validated against an exhaustive search algorithm（ESA）, other than the proposed algorithm. The developed algorithm takes into account weather effects, step climbs during cruise and air traffic management constraints such as constant altitude segments, constant cruise Mach, and a pre-defined reference lateral navigation route. The aircraft fuel burn was computed using a numerical performance model which was created and validated using flight test experimental data.展开更多
A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal...A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal components,electric motor,system efficiency optimization models are developed.According to the target of instantaneous optimization of system efficiency,operating ranges of each mode of power-train are determined,and the corresponding energy management strategies are established.The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy,and keep battery state of charge（SOC）change in a reasonable variation range.展开更多
The implementation of modern brand strategy is an inevitable means to promote the development of China's modern enterprises. As a comprehensive external embodiment of an enterprise, brand strategy has profound sig...The implementation of modern brand strategy is an inevitable means to promote the development of China's modern enterprises. As a comprehensive external embodiment of an enterprise, brand strategy has profound significance and connotation. Moreover, in the process of implementing the brand strategy and optimizing the operation and management of the enterprise, more attention should be paid to optimizing and perfecting the product quality and service, so as to create a professional brand with unique spiritual connotation. This paper mainly analyzes the management methods of Chinese enterprises after brand strategy optimization, and puts forward specific optimization strategies, hoping to lay a foundation for the good development of Chinese modern enterprises.展开更多
At the present stage, our country is in the process of continuous reform of the market economy system and continuous changes in the social market economy environment. This social phenomenon can bring many opportunitie...At the present stage, our country is in the process of continuous reform of the market economy system and continuous changes in the social market economy environment. This social phenomenon can bring many opportunities for the future development of our state-owned enterprises. An important opportunity for the rapid development of China's state-owned enterprises is to build a unique competitive advantage from the internal system. In this development process, internal system control plays a very key leading role. Before that, we formulated new requirements and standards. Actively adapt to the development trend of the times, adapt to the increasingly strict management requirements, the focus of contract management of state-owned enterprises gradually turned to analyze the existing problems and specific preventive measures. At the same time, since most companies operate in accordance with the law, the more effective the contract management is, the fewer economic disputes will be, and the better the long-term development of the company will be. Under this background, it is of great macro-realistic significance to study some problems in the current labor contract risk management of state-owned enterprises and relevant preventive measures.展开更多
The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cutting...The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even-and uneven-aged management. This study developed a method for opti-mizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sow-ing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50%of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97-99%of cases. It was calculated that the minimum basal area re-quirement reduced the mean net present value of the stands by 12-16%when discount rate was 3-5%.展开更多
AIM:To minimize the complications and mortality and improve the survival in primary liver cancer (PLC) patients undergoing hepatic resection. METHODS: We conducted a retrospective analysis of 2143 PLC patients treated...AIM:To minimize the complications and mortality and improve the survival in primary liver cancer (PLC) patients undergoing hepatic resection. METHODS: We conducted a retrospective analysis of 2143 PLC patients treated from January 1990 to January 2004. The patients were divided into two groups using January 1997 as a cut-off. Small tumor size (< 5 cm), preoperative redox tolerance index (RTI), vascular control method, and postoperative arterial ketone body ratio (AKBR) were used as indicators of surgical outcome. RESULTS: Small tumors had less complications and lower mortality and higher overall survival rate. Use of RTI for selecting patients and types of hepatectomy, reduced complications (21.1% vs 11.0%) and mortality (1.6% vs 0.3%). The half liver vascular occlusion protocol (n = 523) versus the Pringle method (n = 476) showed that the former significantly reduced the postoperative complications (25.8% vs 11.9%) and mortality (2.3% vs 0.6%) respectively, and cut mean hospital stay was 3.5 d. Postoperative AKBR was a reliable indicator of the energy status in survivors. CONCLUSION: RTI is of value in predicting hepatic functional reserve, half liver occlusion could protect the residual liver function, and AKBR measurement is a simple and accurate means of assessing the state of postoperative metabolism. Optimal perioperative management is an important factor for minimizing complications and mortality in patients undergoing hepatic resection.展开更多
The energy management may perform well under normal conditions, but may lead to poor behavior under abnormal situations. To tackle this problem, an optimal control strategy called rule-based equivalent fuel consumptio...The energy management may perform well under normal conditions, but may lead to poor behavior under abnormal situations. To tackle this problem, an optimal control strategy called rule-based equivalent fuel consumption minimization strategy （RECMS） is developed for a new complex hybrid electric vehicle （CHEV）. It optimizes the energy efficiency and drive performance to cater for normal and power-loss operations of the tractive motor. Firstly, the strategy formulates a novel objective function based on the equivalent fuel concept. By accounting for the actual fuel cost, the equivalent fuel cost for the electric machines and virtual fuel cost for the drivability, the cost function is obtained. Furthermore, some penalty factors are presented to optimize the performance target. Finally, experiments for a practical CHEV are performed to validate a simulation model. Then simulations are carried out for both rule-based and RECMS. The results show that the optimal energy management is working well.展开更多
Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item ...Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.展开更多
Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single ag...Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single agronomic management practice to increase yield and production efficiency and decrease environmental costs,few have investigated the effects of IAPM systems.A field experiment was conducted using four IAPM systems,a local smallholder farmers’practice system(T1),an improved management system(T2),a high-yield production system(T3),and an optimized management system(OMS),to study the annual yield,greenhouse gas(GHG)emissions,carbon(C)footprint(CF),and net environmental ecological benefit(NEEB)of summer maize.The results revealed that OMS was the most advantageous choice of IAPM,which increased yield and NUE and reduced GHG emissions and CF.Under OMS,yield and NUE were 42.6%and 88.1%higher,and N_(2)O,CO_(2),and CH4 emissions were on average 35.4%,5.8%,and 156.5%lower,respectively,than those under T1.Of the four IAPM systems,OMS resulted in the best soil quality,the lowest soil bulk density,the highest soil C/N ratio,and the highest soil total organic C content,which contributed to reduced GHG emissions.Carbon footprint and cost were the lowest under OMS,which decreased fertilizer input and GHG emissions.Optimized management system reduced CF and C cost by 5.9%and 33.9%,respectively,and increased NEEB by 111.4%compared to T1.Although T3 had the highest yield,it also had the highest GHG emissions and CF.In conclusion,OMS delivered a high yield and NUE while mitigating negative environmental impacts and increasing NEEB.Therefore,OMS is a suitable management system to increase the productivity and sustainability of summer maize.展开更多
Three numeric simulation and optimal management models on groundwater resources are introduced in this paper. These models stand for the present developing levels on the technology of groundwater modeling and optimal ...Three numeric simulation and optimal management models on groundwater resources are introduced in this paper. These models stand for the present developing levels on the technology of groundwater modeling and optimal management in China, and show the practical application situations of the technology. Each of the technology of unique characteristics and purposes. According to the tests of the practical engineering, these models have played a very important role in solving the difficult problems of groundwater resources.展开更多
A microgrid(MG)refers to a set of loads,generation resources and energy storage systems acting as a controllable load or a generator to supply power and heating to a local area.The MG-generated power management is a c...A microgrid(MG)refers to a set of loads,generation resources and energy storage systems acting as a controllable load or a generator to supply power and heating to a local area.The MG-generated power management is a central topic for MG design and operation.The existence of dispersed generation(DG)resources has faced MG management with new issues.Depending on the level of exchanges between an MG and the main grid,the MG operation states can be divided into independent or grid-connected ones.Energy management in MGs aims to supply power at the lowest cost for optimal load response.This study examines MG energy management in two operational modes of islanded and grid-connected,and proposes a structure with two control layers(primary and secondary)for energy management.At the principal level of control,the energy management system is determined individually for all MG by taking into consideration the probability constraints and RES uncertainty by the Weibull the probability density function(PDF),generation resources’power as well as the generation surplus and deficit of each MG.Then,the information of the power surplus and deficit of each MG must be sent to the central energy management system.To confirm the proposed structure,a case system with two MGs and a condensive load is simulated by using a multi-time harmony search algorithm.Several scenarios are applied to evaluate the performance of this algorithm.The findings clearly show the effectiveness of the proposed system in the energy management of several MGs,leading to the optimal performance of the resources per MG.Moreover,the proposed control scheme properly controls the MG and grid’s performance in their interactions and offers a high level of robustness,stable behavior under different conditions and high quality of power supply.展开更多
The paper gives an overview on the need for smart coupling for battery management in grid integrated renewable energy system （RES）. Grid integrated photovoltaic （PV） battery system, as being popular and extensivel...The paper gives an overview on the need for smart coupling for battery management in grid integrated renewable energy system （RES）. Grid integrated photovoltaic （PV） battery system, as being popular and extensively used has been discussed in the paper. Smart coupling refers to intelligent grid integration such that it can foresee local network conditions and issue battery power flow management strategy accordingly to shave the peak PV and peak load. Therefore, a need for predictive energy management arises for smart integration to the grid and supervision of the power flow in accordance to the grid conditions. This is also a running project at the Institute of Energy Systems （INES）, Offenburg University of Applied Science, Germany since January, 2015. The paper should provide insights to the motivation, need and gives an outlook to the features of desired predictive energy management system （PEMS）.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
文摘The economic management of colleges and universities has always been a topic of great concern to China’s educational career,therefore,this paper will firstly make the necessary analysis of the current implementation of the economic management of colleges and universities in China,and then the reasons for the problems of economic management of colleges and universities in China is realized a detailed investigation,and finally,the economic management of colleges and universities based on capital and cost management optimization strategy is made a full discussion,looking forward to providing the necessary guidance for researchers in this field.
文摘At present, with the continuous progress of the times, China's social and economic level has been significantly improved. In order to improve the quality of life of our people, the civil aviation industry has carried out the corresponding optimization of aircraft maintenance work. In this regard, this paper analyzes and studies some problems existing in aircraft maintenance in China's civil aviation industry at present, and in order to effectively improve the overall maintenance quality and management level of the aircraft and promote the development of the civil aviation industry, puts forward corresponding optimization suggestions and maintenance measures.
基金supported by the KESTO project (Planning and implementation of the harvesting of climate-resilient continuous cover forests (CCF) using digitalization in North Karelia),Grant Number 41007-00241901funded by the European Regional Development Fund (ERDF)funding provided by University of Eastern Finland (including Kuopio University Hospital)
文摘The current trends in forestry in Europe include the increased use of continuous cover forestry(CCF)and the increased availability of tree-level forest inventory data.Accordingly,recent literature suggests methodologies for optimizing the harvest decisions at the tree level.Using tree-level optimization for all trees of the stand is computationally demanding.This study proposed a two-level optimization method for CCF where the harvest prescriptions are optimized at the tree level for only a part of the trees or the first cuttings.The higher-level algorithm optimizes the cutting years and the harvest rates of those diameter classes for which tree-level optimization is not used.The lower-level algorithm allocates the individually optimized trees to different cutting events.The most detailed problem formulations,employing much tree-level optimization,resulted in the highest net present value and longest optimization time.However,restricting tree-level optimization to the largest trees and first cuttings did not significantly alter the time,intensity,or type of first cutting.Computing times could also be shortened by applying accumulated knowledge from previous optimizations,implementing learning aspects in heuristic search,and optimizing the search algorithms for short computing time and good-quality solutions.
文摘Small municipal projects,constrained by resources and extensive management models,commonly face issues of delayed progress and cost overruns.This study uses a road renovation project in a city as an empirical case.By integrating BIM collaborative platforms with real-time IoT monitoring systems,it achieves construction conflict prediction and dynamic resource allocation.Combining rolling planning methods and risk probability models,a“forecast-adaptation”dual-mode management framework is formed.After implementation,the total duration was shortened by 15%,the rework rate decreased by 20%,and inter-departmental communication efficiency improved by 30%.The case validates the effectiveness of digital tools and dynamic mechanisms working together to optimize,aligning with the requirements for refined control outlined in the“Construction Engineering Quantity List Pricing Standard”(GB/T50500-2024).It provides a replicable progress management paradigm for similar projects.
文摘With the advancement of globalization and information technology,the financial sharing mode has gradually emerged as a crucial means for enterprises to optimize their financial management.Particularly within the context of economic globalization,informatization,and digital transformation,enterprises find themselves navigating a rapidly evolving market environment by intensifying competition.To enhance efficiency and competitiveness,many enterprises have embraced the financial sharing model to streamline financial management processes,curtail costs,and bolster the execution of corporate strategies.This article aims to dissect the definition and essence of the financial sharing model and its significance in the realm of enterprise financial management.Drawing upon this analysis and aligning with the needs of enterprise financial management,the article proposes ideas for optimizing management practices,aspiring to foster reform and innovation in enterprise financial management while enhancing its level of financial management and ability to respond to financial risks.This contribution seeks to provide valuable insights for practitioners in the field.
文摘With the improvement of social and economic development level, China's construction industry is also developing continuously. Therefore, many new problems have emerged in its construction site management. These problems will seriously affect the smooth implementation of the whole construction project. In addition, they may lead to personal safety risks. Therefore,It is necessary to optimize these construction site management. We should fully consider all links in the construction process and analyze them comprehensively, so as to continuously promote the smooth implementation of construction projects in our country.Next, the article discusses the optimization strategy of construction site management.
基金the team of the Business-led Network of Centers of Excellence Green Aviation Research & Development Network (GARDN)in particular Mr. Sylvan Cofsky, for the funds received for this project (GARDNⅡ–Project: CMC-21)conducted at The Research Laboratory in Active Controls, Avionics and Aeroservoelasticity (LARCASE) in the framework of the global project ‘‘Optimized Descent and Cruise”
文摘With the objective of reducing the flight cost and the amount of polluting emissions released in the atmosphere, a new optimization algorithm considering the climb, cruise and descent phases is presented for the reference vertical flight trajectory. The selection of the reference vertical navigation speeds and altitudes was solved as a discrete combinatory problem by means of a graphtree passing through nodes using the beam search optimization technique. To achieve a compromise between the execution time and the algorithm＇s ability to find the global optimal solution, a heuristic methodology introducing a parameter called ‘‘optimism coefficient was used in order to estimate the trajectory＇s flight cost at every node. The optimal trajectory cost obtained with the developed algorithm was compared with the cost of the optimal trajectory provided by a commercial flight management system（FMS）. The global optimal solution was validated against an exhaustive search algorithm（ESA）, other than the proposed algorithm. The developed algorithm takes into account weather effects, step climbs during cruise and air traffic management constraints such as constant altitude segments, constant cruise Mach, and a pre-defined reference lateral navigation route. The aircraft fuel burn was computed using a numerical performance model which was created and validated using flight test experimental data.
基金Supported by the National Science and Technology Support Program(2013BAG12B01)Foundational and Advanced Research Program General Project of Chongqing City(cstc2013jcyjjq60002)
文摘A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle（HEV）equipped with continuously variable transmission（CVT）is proposed.Based on consideration of the efficiency of pivotal components,electric motor,system efficiency optimization models are developed.According to the target of instantaneous optimization of system efficiency,operating ranges of each mode of power-train are determined,and the corresponding energy management strategies are established.The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy,and keep battery state of charge（SOC）change in a reasonable variation range.
文摘The implementation of modern brand strategy is an inevitable means to promote the development of China's modern enterprises. As a comprehensive external embodiment of an enterprise, brand strategy has profound significance and connotation. Moreover, in the process of implementing the brand strategy and optimizing the operation and management of the enterprise, more attention should be paid to optimizing and perfecting the product quality and service, so as to create a professional brand with unique spiritual connotation. This paper mainly analyzes the management methods of Chinese enterprises after brand strategy optimization, and puts forward specific optimization strategies, hoping to lay a foundation for the good development of Chinese modern enterprises.
文摘At the present stage, our country is in the process of continuous reform of the market economy system and continuous changes in the social market economy environment. This social phenomenon can bring many opportunities for the future development of our state-owned enterprises. An important opportunity for the rapid development of China's state-owned enterprises is to build a unique competitive advantage from the internal system. In this development process, internal system control plays a very key leading role. Before that, we formulated new requirements and standards. Actively adapt to the development trend of the times, adapt to the increasingly strict management requirements, the focus of contract management of state-owned enterprises gradually turned to analyze the existing problems and specific preventive measures. At the same time, since most companies operate in accordance with the law, the more effective the contract management is, the fewer economic disputes will be, and the better the long-term development of the company will be. Under this background, it is of great macro-realistic significance to study some problems in the current labor contract risk management of state-owned enterprises and relevant preventive measures.
文摘The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even-and uneven-aged management. This study developed a method for opti-mizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sow-ing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50%of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97-99%of cases. It was calculated that the minimum basal area re-quirement reduced the mean net present value of the stands by 12-16%when discount rate was 3-5%.
文摘AIM:To minimize the complications and mortality and improve the survival in primary liver cancer (PLC) patients undergoing hepatic resection. METHODS: We conducted a retrospective analysis of 2143 PLC patients treated from January 1990 to January 2004. The patients were divided into two groups using January 1997 as a cut-off. Small tumor size (< 5 cm), preoperative redox tolerance index (RTI), vascular control method, and postoperative arterial ketone body ratio (AKBR) were used as indicators of surgical outcome. RESULTS: Small tumors had less complications and lower mortality and higher overall survival rate. Use of RTI for selecting patients and types of hepatectomy, reduced complications (21.1% vs 11.0%) and mortality (1.6% vs 0.3%). The half liver vascular occlusion protocol (n = 523) versus the Pringle method (n = 476) showed that the former significantly reduced the postoperative complications (25.8% vs 11.9%) and mortality (2.3% vs 0.6%) respectively, and cut mean hospital stay was 3.5 d. Postoperative AKBR was a reliable indicator of the energy status in survivors. CONCLUSION: RTI is of value in predicting hepatic functional reserve, half liver occlusion could protect the residual liver function, and AKBR measurement is a simple and accurate means of assessing the state of postoperative metabolism. Optimal perioperative management is an important factor for minimizing complications and mortality in patients undergoing hepatic resection.
基金the National High Technology Research and Development Program (863) of China(No. 2006AA11A127)
文摘The energy management may perform well under normal conditions, but may lead to poor behavior under abnormal situations. To tackle this problem, an optimal control strategy called rule-based equivalent fuel consumption minimization strategy （RECMS） is developed for a new complex hybrid electric vehicle （CHEV）. It optimizes the energy efficiency and drive performance to cater for normal and power-loss operations of the tractive motor. Firstly, the strategy formulates a novel objective function based on the equivalent fuel concept. By accounting for the actual fuel cost, the equivalent fuel cost for the electric machines and virtual fuel cost for the drivability, the cost function is obtained. Furthermore, some penalty factors are presented to optimize the performance target. Finally, experiments for a practical CHEV are performed to validate a simulation model. Then simulations are carried out for both rule-based and RECMS. The results show that the optimal energy management is working well.
基金The Key Project of the National Ninth-Five-Year Plan No. 96-004-02-09The 48Project of Ministry of Water Resources No. 985106The Project of Chinese Academy of Sciences
文摘Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.
基金funded by China Agriculture Research System of Ministry of Finance and Ministry of Agriculture and Rural Affairs and the National Key and Development Program of China(No.2017YFD0300304).
文摘Integrated agronomic practice management(IAPM)is an effective strategy for increasing nitrogen(N)use efficiency(NUE)and yield during crop production.Although various studies have evaluated the mechanism of a single agronomic management practice to increase yield and production efficiency and decrease environmental costs,few have investigated the effects of IAPM systems.A field experiment was conducted using four IAPM systems,a local smallholder farmers’practice system(T1),an improved management system(T2),a high-yield production system(T3),and an optimized management system(OMS),to study the annual yield,greenhouse gas(GHG)emissions,carbon(C)footprint(CF),and net environmental ecological benefit(NEEB)of summer maize.The results revealed that OMS was the most advantageous choice of IAPM,which increased yield and NUE and reduced GHG emissions and CF.Under OMS,yield and NUE were 42.6%and 88.1%higher,and N_(2)O,CO_(2),and CH4 emissions were on average 35.4%,5.8%,and 156.5%lower,respectively,than those under T1.Of the four IAPM systems,OMS resulted in the best soil quality,the lowest soil bulk density,the highest soil C/N ratio,and the highest soil total organic C content,which contributed to reduced GHG emissions.Carbon footprint and cost were the lowest under OMS,which decreased fertilizer input and GHG emissions.Optimized management system reduced CF and C cost by 5.9%and 33.9%,respectively,and increased NEEB by 111.4%compared to T1.Although T3 had the highest yield,it also had the highest GHG emissions and CF.In conclusion,OMS delivered a high yield and NUE while mitigating negative environmental impacts and increasing NEEB.Therefore,OMS is a suitable management system to increase the productivity and sustainability of summer maize.
文摘Three numeric simulation and optimal management models on groundwater resources are introduced in this paper. These models stand for the present developing levels on the technology of groundwater modeling and optimal management in China, and show the practical application situations of the technology. Each of the technology of unique characteristics and purposes. According to the tests of the practical engineering, these models have played a very important role in solving the difficult problems of groundwater resources.
文摘A microgrid(MG)refers to a set of loads,generation resources and energy storage systems acting as a controllable load or a generator to supply power and heating to a local area.The MG-generated power management is a central topic for MG design and operation.The existence of dispersed generation(DG)resources has faced MG management with new issues.Depending on the level of exchanges between an MG and the main grid,the MG operation states can be divided into independent or grid-connected ones.Energy management in MGs aims to supply power at the lowest cost for optimal load response.This study examines MG energy management in two operational modes of islanded and grid-connected,and proposes a structure with two control layers(primary and secondary)for energy management.At the principal level of control,the energy management system is determined individually for all MG by taking into consideration the probability constraints and RES uncertainty by the Weibull the probability density function(PDF),generation resources’power as well as the generation surplus and deficit of each MG.Then,the information of the power surplus and deficit of each MG must be sent to the central energy management system.To confirm the proposed structure,a case system with two MGs and a condensive load is simulated by using a multi-time harmony search algorithm.Several scenarios are applied to evaluate the performance of this algorithm.The findings clearly show the effectiveness of the proposed system in the energy management of several MGs,leading to the optimal performance of the resources per MG.Moreover,the proposed control scheme properly controls the MG and grid’s performance in their interactions and offers a high level of robustness,stable behavior under different conditions and high quality of power supply.
基金supported by E-Werk Mittelbaden AG,Offenburg,Germany
文摘The paper gives an overview on the need for smart coupling for battery management in grid integrated renewable energy system （RES）. Grid integrated photovoltaic （PV） battery system, as being popular and extensively used has been discussed in the paper. Smart coupling refers to intelligent grid integration such that it can foresee local network conditions and issue battery power flow management strategy accordingly to shave the peak PV and peak load. Therefore, a need for predictive energy management arises for smart integration to the grid and supervision of the power flow in accordance to the grid conditions. This is also a running project at the Institute of Energy Systems （INES）, Offenburg University of Applied Science, Germany since January, 2015. The paper should provide insights to the motivation, need and gives an outlook to the features of desired predictive energy management system （PEMS）.
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.
