We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art...We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art literature related to the subject, in order to cross, to compare, and to organize the relevant contents to create a logical and consistent support to the finds. We show that it is consistent to assume that persistent hyperglycemia and diabetes mellitus can have precursors not only in pancreas, but also in brain, mainly induced by noxious dysfunctions of hypothalamus sensor neurons circuits and external noxious elements, causing pancreas overload, and the consequent exhaustion—overburden.展开更多
BACKGROUND Post-hepatectomy liver failure(PHLF),represents a serious complication after liver resection,significantly impacting the long-term outcomes for patients who undergo such surgeries.There exists a strong corr...BACKGROUND Post-hepatectomy liver failure(PHLF),represents a serious complication after liver resection,significantly impacting the long-term outcomes for patients who undergo such surgeries.There exists a strong correlation between intraoperative hemorrhage and transfusion requirements with the development of PHLF.Presently,a combination of hepatic portal occlusion techniques alongside con-trolled low central venous pressure(CLCVP)methodologies is extensively em-ployed to mitigate intraoperative bleeding.Nonetheless,limited studies have analyzed the risk factors for PHLF under CLCVP.AIM To develop and validate a nomogram that predicts the risk factors associated with the development of PHLF patients undergoing liver resection with CLCVP.METHODS We conducted a retrospective analysis of 285 patients who underwent hepatectomy for the first time and had no history of prior non-index abdominal surgeries,with hepatic inflow occlusion combined with CLCVP from January to December 2019 in Hunan Provincial People’s Hospital.Univariate and multivariate regression analyses were used to identify preoperative and intraoperative risk factors for PHLF.Eligible patients were randomly divided into training and validation groups in a 7:3 ratio,and a nomogram prediction model was constructed.RESULTS The incidence of PHLF in these patients was 22.46%.Multiple logistic analysis showed that preoperative serum albumin level,causes of liver resection(cancer or others),and cirrhosis were independent preoperative risk factors for PHLF(P<0.05)and that only post-blocking blood potassium concentration was an independent intraoperative risk factor for PHLF(P<0.05).Least absolute shrinkage and selection operator regression analysis revealed that preoperative serum albumin level,direct bilirubin level(DBIL),platelet count,causes of liver resection(cancer or others),and cirrhosis were significant predictors of PHLF.The nomogram risk prediction model based on preoperative serum albumin level,DBIL,platelet count,causes of liver resection(cancer or others),cirrhosis and post-blocking blood potassium concentration can better predict the occurrence of PHLF.CONCLUSION For patients undergoing liver resection with CLCVP,serum albumin level,DBIL,platelet count,causes of liver resection(cancer or others),and cirrhosis are independent preoperative risk factors for PHLF.展开更多
How to control the dynamic behavior of large-scale artificial active matter is a critical concern in experimental research on soft matter, particularly regarding the emergence of collective behaviors and the formation...How to control the dynamic behavior of large-scale artificial active matter is a critical concern in experimental research on soft matter, particularly regarding the emergence of collective behaviors and the formation of group patterns. Centralized systems excel in precise control over individual behavior within a group, ensuring high accuracy and controllability in task execution. Nevertheless, their sensitivity to group size may limit their adaptability to diverse tasks. In contrast, decentralized systems empower individuals with autonomous decision-making, enhancing adaptability and system robustness. Yet, this flexibility comes at the cost of reduced accuracy and efficiency in task execution. In this work, we present a unique method for regulating the centralized dynamic behavior of self-organizing clusters based on environmental interactions. Within this environment-coupled robot system, each robot possesses similar dynamic characteristics, and their internal programs are entirely identical. However, their behaviors can be guided by the centralized control of the environment, facilitating the accomplishment of diverse cluster tasks. This approach aims to balance the accuracy and flexibility of centralized control with the robustness and task adaptability of decentralized control. The proactive regulation of dynamic behavioral characteristics in active matter groups, demonstrated in this work through environmental interactions, holds the potential to introduce a novel technological approach and provide experimental references for studying the dynamic behavior control of large-scale artificial active matter systems.展开更多
As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by g...As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.展开更多
The influence of a node in a network can be characterized by its macroscopic properties such as eigenvector centrality. An issue of significant theoretical and practical interest is to modify the influence or roles of...The influence of a node in a network can be characterized by its macroscopic properties such as eigenvector centrality. An issue of significant theoretical and practical interest is to modify the influence or roles of the nodes in a network, and recent advances indicate that this can be achieved by just controlling a subset of nodes： the socalled controllers. However, the relationship between the structural properties of a network and its controllability, e.g., the control of node importance, is still not well understood. Here we systematically＂ explore this relationship by constructing scale-free networks with a fixed degree sequence and tunable network characteristics. We calculate the relative size （nc＊） of the minimai controlling set required to controi the importance of each individual node in a network. It is found that while clustering has no significant impact on nc＊, changes in degree-degree correlations, heterogeneity and the average degree of networks demonstrate a discernible impact on its controllability.展开更多
The interference reduction capability of cell sectoring and power control algorithms have been considered separately as means to decrease the interference in Code Division Multiple Access (CDMA) cellular systems. In t...The interference reduction capability of cell sectoring and power control algorithms have been considered separately as means to decrease the interference in Code Division Multiple Access (CDMA) cellular systems. In this paper, we present Switched-Beam (SB) and Rotatable Equal Sectoring (RES) techniques for CDMA cellular systems in a 2D urban environment. In the SB technique by using a number of fixed, independent, or directional antennas we increase the downlink capacity of the CDMA systems. Also in the RES method, the equal sectors of the base stations are rotating together to decrease the inter-cell and intra-cell interferences. Also in this paper we use centralized power control to overcome the near-far problem. Simulation results indicate that the proposed techniques considerably increase the capacity of the CDMA cellular systems compared to ordinary Equal Sectoring (ES) method.展开更多
Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem,...Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem, centralized control over cascade hydropower stations is practiced with a considerable economic benef it gained.展开更多
Sandi Arabia is renown for its rich oil and gas Mesozoic. However, the discovery of Paleozoic fields in resources with the bulk of the reserves reservo/red in the the late 1980s has encouraged further exploration in t...Sandi Arabia is renown for its rich oil and gas Mesozoic. However, the discovery of Paleozoic fields in resources with the bulk of the reserves reservo/red in the the late 1980s has encouraged further exploration in the Paleozoic. This paper reviews the salient features of the Paleozoic petroleum geology in central Saudi Arabia and discusses the main factors controlling hydrocarbon accumulation in the Paleozoic. The Lower Silurian Qusaiba hot shale is the principal source rock for the hydrocarbons discovered in the Ordovician to Permian reservoirs. Of them, the Permo- Carboniferous Unayzah and Upper Ordovician Sarah Formations have the best exploration potential. The key factors controlling hydrocarbon accumulation in the Unayzah Formation are migration pathways and reservoir petrophysics. The key factors controlling hydrocarbon accumulation in the Sarah Formation are reservoir petrophysics and the development of structural traps.展开更多
This paper introduces the upgrading process and application effect of centralized control of water treatment system in 850 rolling line. At the beginning of the design, the water treatment system of Delong Iron and St...This paper introduces the upgrading process and application effect of centralized control of water treatment system in 850 rolling line. At the beginning of the design, the water treatment system of Delong Iron and Steel 850 rolling line was composed of four parts, including the primary tank system, laminar flow pump room system, central pump room system and high-pressure water system. The design was all operated by the machine side operation box. In order to meet the requirements of automatic operation, the whole water treatment system was upgraded and reformed in combination with NARI company. NARI PCS control system is used for centralized control. Through upgrading, all the control modes in the above areas are centralized to the control console, and unified centralized operation is carried out through PLC. This paper provides a reference for the upgrading of water treatment system and the design and application of control system in steel rolling plant.展开更多
In recent years, with the rapid development of society, the demand for electric energy in the production field and life field is increasing, and the power supply quality is directly related to the performance of centr...In recent years, with the rapid development of society, the demand for electric energy in the production field and life field is increasing, and the power supply quality is directly related to the performance of centralized control operation steam turbine in power plant. Once there is an operation problem, it will lead to the reduction of smooth power supply, poor quality, and even affect the production and life of society, damage to the benefits of the power plant. Based on this, the author studies and discusses the centralized control operation of steam turbine, analyzes the existing shortcomings, and puts forward relevant operation optimization measures, in order to lay a solid foundation for improving the power generation quality and production efficiency of power plant.展开更多
One of the key tasks of centralized control operation of thermal power plant is to pre-control dangerous points, which ensures the safety of the whole thermal power plant. Therefore, it is necessary to understand the ...One of the key tasks of centralized control operation of thermal power plant is to pre-control dangerous points, which ensures the safety of the whole thermal power plant. Therefore, it is necessary to understand the main dangerous points and causes of centralized control operation, so as to take effective solutions, implementing preventive pre-control, and ensuring the safety of thermal power plant.展开更多
Under the background of rapid development of science and technology, people's quality of life continues to improve. In the actual life and production of modern people, there is almost no way to separate from the a...Under the background of rapid development of science and technology, people's quality of life continues to improve. In the actual life and production of modern people, there is almost no way to separate from the actual application of energy. Therefore, it is crucial to ensure normal and stable power generation. A normal power plant requires hard work from the staff. In the power plant, centralized control personnel are responsible for the normal production, delivery of facilities, design planning, inspection and maintenance. This paper will analyze and explain the training measures for the centralized control operation personnel of the newly-built power plant, hoping to provide some suggestions and ideas for the corresponding personnel.展开更多
The stable operation of thermal power plants is the core condition to ensure the stable power supply. Therefore, the application of unit centralized control technology around the three parts of the electromechanical f...The stable operation of thermal power plants is the core condition to ensure the stable power supply. Therefore, the application of unit centralized control technology around the three parts of the electromechanical furnace system layout, system principle, fixed value parameters, operation mode, logic and operation procedures control can improve the power generation stability of thermal power plants. Based on this, this paper first summarizes the concept of centralized control of thermal power plants and generating units, and then focuses on the principles and technical solutions of the application of centralized control technology of generating units.展开更多
An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature con...An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature control systems, and then parameters in the cold load model and in the central air-conditioning system model are estimated. Generalized predictive control (GPC) is used to establish an optimization model to minimize the consumption of energy and the control error of temperature. The simulated annealing (SA) algorithm, combined with quadratic programming, is adopted to solve the optimal problem. Contrasted with the simulation of traditional PID control, the results prove the effectiveness of this proposed strategy.展开更多
Software-Defined Networking(SDN)improves network management by separating its control logic from the underlying hardware and integrating it into a logically centralized control unit,termed the SDN controller.SDN adapt...Software-Defined Networking(SDN)improves network management by separating its control logic from the underlying hardware and integrating it into a logically centralized control unit,termed the SDN controller.SDN adaptation is essential for wireless networks because it offers enhanced and data-intensive services.The initial intent of the SDN design was to have a physically centralized controller.However,network experts have suggested logically centralized and physically distributed designs for SDN controllers,owing to issues such as a single point of failure and scalability.This study addressed the security,scalability,reliability,and consistency issues associated with the design of distributed SDN controllers.Moreover,the security issues of an enterprise related to multiple physically distributed controllers in a software-defined wireless local area network(SD-WLAN)were emphasized,and optimal solutions were suggested.展开更多
Mr.Jiang Zcmin,Gencral-Seerctary of the Cen-tral Committee of the Chincse Communist Party and.Chairman of the People's Republic of China,in a rC-ccnt spcech cm phasized that the family planning pro-gramme should b...Mr.Jiang Zcmin,Gencral-Seerctary of the Cen-tral Committee of the Chincse Communist Party and.Chairman of the People's Republic of China,in a rC-ccnt spcech cm phasized that the family planning pro-gramme should be strictly and effectively im plemented in 1994,a year of crucial importance for promoting re-form and opening and thc drive lowards.modernization.To makc continucd contributions to the sociocconomic development in the country,we must fulfil the plan for controlling population growth..The spcech was delivcred at the anua!National Fo-rum on Family Planning Work convened jointly by the Party's Central Committcc and the Statc Council.展开更多
A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to d...A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to discuss the design of fuzzy controller using common microprogrammed control unit (MCU) in detail. Based on fuzzy theory the query control tables fixed in read only memory (ROM) of MCU are established to realize the energy saving in the room temperature controller and the reasoning procedure is analyzed. The diagram of hardware design and the flow chart of software of room temperature controller are presented. The results show that the proposed method is practical and effective to achieve the energy saving goal.展开更多
The alternative energy resources, like solar, are always complementary due to environmental changes. Energy generation with the sources such as solar and wind is gaining importance and of that photovoltaic conversion ...The alternative energy resources, like solar, are always complementary due to environmental changes. Energy generation with the sources such as solar and wind is gaining importance and of that photovoltaic conversion is the main focus of researches due to its promising potential as the electrical source. This paper presents the constant voltage method of control where the output of the converter is maintained constant irrespective of the variations in the irradiance with the high step-up isolated efficient single switch DC-DC converter for the solar PV systems. Constant voltage method of control uses the array of photovoltaic systems as its energy source. The output of the Solar PV systems is nonlinear and has its dependency on temperature and irradiance by which the panel voltage and current varies with the variation in irradiance. Constant voltage control method always operates in such a way that the converter voltage is tried to be maintained constantly to the reference voltage which is set by the user. The system used here utilizes high step single switch isolated DC-DC converter and monitors the voltage continuously by varying the duty cycle to maintain the converter voltage always constant. As a way of improving the performance, both the open and closed loop analysis is done where the closed loop analysis uses the PI controller for its performance. The model is implemented in MATLAB and it accepts the irradiance as the input and outputs the constant voltage from the converter and the feasibility of the proposed converter topology is confirmed with experimental results of the prototype model.展开更多
文摘We study afresh how the glucose control system anomalies impact the organicity of the glucose homeostasis and build up events of persistent hyperglycemia and diabetes mellitus. We have used critically the state of art literature related to the subject, in order to cross, to compare, and to organize the relevant contents to create a logical and consistent support to the finds. We show that it is consistent to assume that persistent hyperglycemia and diabetes mellitus can have precursors not only in pancreas, but also in brain, mainly induced by noxious dysfunctions of hypothalamus sensor neurons circuits and external noxious elements, causing pancreas overload, and the consequent exhaustion—overburden.
基金Supported by the Natural Science Foundation of Hunan Province,No.2018JJ3291the Scientific Research Project of the Hunan Provincial Health Commission,No.202104111288.
文摘BACKGROUND Post-hepatectomy liver failure(PHLF),represents a serious complication after liver resection,significantly impacting the long-term outcomes for patients who undergo such surgeries.There exists a strong correlation between intraoperative hemorrhage and transfusion requirements with the development of PHLF.Presently,a combination of hepatic portal occlusion techniques alongside con-trolled low central venous pressure(CLCVP)methodologies is extensively em-ployed to mitigate intraoperative bleeding.Nonetheless,limited studies have analyzed the risk factors for PHLF under CLCVP.AIM To develop and validate a nomogram that predicts the risk factors associated with the development of PHLF patients undergoing liver resection with CLCVP.METHODS We conducted a retrospective analysis of 285 patients who underwent hepatectomy for the first time and had no history of prior non-index abdominal surgeries,with hepatic inflow occlusion combined with CLCVP from January to December 2019 in Hunan Provincial People’s Hospital.Univariate and multivariate regression analyses were used to identify preoperative and intraoperative risk factors for PHLF.Eligible patients were randomly divided into training and validation groups in a 7:3 ratio,and a nomogram prediction model was constructed.RESULTS The incidence of PHLF in these patients was 22.46%.Multiple logistic analysis showed that preoperative serum albumin level,causes of liver resection(cancer or others),and cirrhosis were independent preoperative risk factors for PHLF(P<0.05)and that only post-blocking blood potassium concentration was an independent intraoperative risk factor for PHLF(P<0.05).Least absolute shrinkage and selection operator regression analysis revealed that preoperative serum albumin level,direct bilirubin level(DBIL),platelet count,causes of liver resection(cancer or others),and cirrhosis were significant predictors of PHLF.The nomogram risk prediction model based on preoperative serum albumin level,DBIL,platelet count,causes of liver resection(cancer or others),cirrhosis and post-blocking blood potassium concentration can better predict the occurrence of PHLF.CONCLUSION For patients undergoing liver resection with CLCVP,serum albumin level,DBIL,platelet count,causes of liver resection(cancer or others),and cirrhosis are independent preoperative risk factors for PHLF.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12174041)China Postdoctoral Science Foundation (CPSF)(Grant No. 2022M723118)the seed grants from the Wenzhou Institute,University of Chinese Academy of Sciences (Grant No. WIUCASQD2021002)。
文摘How to control the dynamic behavior of large-scale artificial active matter is a critical concern in experimental research on soft matter, particularly regarding the emergence of collective behaviors and the formation of group patterns. Centralized systems excel in precise control over individual behavior within a group, ensuring high accuracy and controllability in task execution. Nevertheless, their sensitivity to group size may limit their adaptability to diverse tasks. In contrast, decentralized systems empower individuals with autonomous decision-making, enhancing adaptability and system robustness. Yet, this flexibility comes at the cost of reduced accuracy and efficiency in task execution. In this work, we present a unique method for regulating the centralized dynamic behavior of self-organizing clusters based on environmental interactions. Within this environment-coupled robot system, each robot possesses similar dynamic characteristics, and their internal programs are entirely identical. However, their behaviors can be guided by the centralized control of the environment, facilitating the accomplishment of diverse cluster tasks. This approach aims to balance the accuracy and flexibility of centralized control with the robustness and task adaptability of decentralized control. The proactive regulation of dynamic behavioral characteristics in active matter groups, demonstrated in this work through environmental interactions, holds the potential to introduce a novel technological approach and provide experimental references for studying the dynamic behavior control of large-scale artificial active matter systems.
基金supported by the National Natural Science Foundation of China(Nos.11232005 and11472104)the Doctoral Fund of Ministry of Education of China(No.20120074110020)
文摘As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.
基金Supported by Foundations of SiChuan Educational Committee under Grant No 13ZB0198the National Natural Science Foundation of China under Grant Nos 61104224,81373531,61104143 and 61573107The Science and Technology Fund Project of SWPU(2013XJR011)
文摘The influence of a node in a network can be characterized by its macroscopic properties such as eigenvector centrality. An issue of significant theoretical and practical interest is to modify the influence or roles of the nodes in a network, and recent advances indicate that this can be achieved by just controlling a subset of nodes： the socalled controllers. However, the relationship between the structural properties of a network and its controllability, e.g., the control of node importance, is still not well understood. Here we systematically＂ explore this relationship by constructing scale-free networks with a fixed degree sequence and tunable network characteristics. We calculate the relative size （nc＊） of the minimai controlling set required to controi the importance of each individual node in a network. It is found that while clustering has no significant impact on nc＊, changes in degree-degree correlations, heterogeneity and the average degree of networks demonstrate a discernible impact on its controllability.
文摘The interference reduction capability of cell sectoring and power control algorithms have been considered separately as means to decrease the interference in Code Division Multiple Access (CDMA) cellular systems. In this paper, we present Switched-Beam (SB) and Rotatable Equal Sectoring (RES) techniques for CDMA cellular systems in a 2D urban environment. In the SB technique by using a number of fixed, independent, or directional antennas we increase the downlink capacity of the CDMA systems. Also in the RES method, the equal sectors of the base stations are rotating together to decrease the inter-cell and intra-cell interferences. Also in this paper we use centralized power control to overcome the near-far problem. Simulation results indicate that the proposed techniques considerably increase the capacity of the CDMA cellular systems compared to ordinary Equal Sectoring (ES) method.
文摘Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem, centralized control over cascade hydropower stations is practiced with a considerable economic benef it gained.
文摘Sandi Arabia is renown for its rich oil and gas Mesozoic. However, the discovery of Paleozoic fields in resources with the bulk of the reserves reservo/red in the the late 1980s has encouraged further exploration in the Paleozoic. This paper reviews the salient features of the Paleozoic petroleum geology in central Saudi Arabia and discusses the main factors controlling hydrocarbon accumulation in the Paleozoic. The Lower Silurian Qusaiba hot shale is the principal source rock for the hydrocarbons discovered in the Ordovician to Permian reservoirs. Of them, the Permo- Carboniferous Unayzah and Upper Ordovician Sarah Formations have the best exploration potential. The key factors controlling hydrocarbon accumulation in the Unayzah Formation are migration pathways and reservoir petrophysics. The key factors controlling hydrocarbon accumulation in the Sarah Formation are reservoir petrophysics and the development of structural traps.
文摘This paper introduces the upgrading process and application effect of centralized control of water treatment system in 850 rolling line. At the beginning of the design, the water treatment system of Delong Iron and Steel 850 rolling line was composed of four parts, including the primary tank system, laminar flow pump room system, central pump room system and high-pressure water system. The design was all operated by the machine side operation box. In order to meet the requirements of automatic operation, the whole water treatment system was upgraded and reformed in combination with NARI company. NARI PCS control system is used for centralized control. Through upgrading, all the control modes in the above areas are centralized to the control console, and unified centralized operation is carried out through PLC. This paper provides a reference for the upgrading of water treatment system and the design and application of control system in steel rolling plant.
文摘In recent years, with the rapid development of society, the demand for electric energy in the production field and life field is increasing, and the power supply quality is directly related to the performance of centralized control operation steam turbine in power plant. Once there is an operation problem, it will lead to the reduction of smooth power supply, poor quality, and even affect the production and life of society, damage to the benefits of the power plant. Based on this, the author studies and discusses the centralized control operation of steam turbine, analyzes the existing shortcomings, and puts forward relevant operation optimization measures, in order to lay a solid foundation for improving the power generation quality and production efficiency of power plant.
文摘One of the key tasks of centralized control operation of thermal power plant is to pre-control dangerous points, which ensures the safety of the whole thermal power plant. Therefore, it is necessary to understand the main dangerous points and causes of centralized control operation, so as to take effective solutions, implementing preventive pre-control, and ensuring the safety of thermal power plant.
文摘Under the background of rapid development of science and technology, people's quality of life continues to improve. In the actual life and production of modern people, there is almost no way to separate from the actual application of energy. Therefore, it is crucial to ensure normal and stable power generation. A normal power plant requires hard work from the staff. In the power plant, centralized control personnel are responsible for the normal production, delivery of facilities, design planning, inspection and maintenance. This paper will analyze and explain the training measures for the centralized control operation personnel of the newly-built power plant, hoping to provide some suggestions and ideas for the corresponding personnel.
文摘The stable operation of thermal power plants is the core condition to ensure the stable power supply. Therefore, the application of unit centralized control technology around the three parts of the electromechanical furnace system layout, system principle, fixed value parameters, operation mode, logic and operation procedures control can improve the power generation stability of thermal power plants. Based on this, this paper first summarizes the concept of centralized control of thermal power plants and generating units, and then focuses on the principles and technical solutions of the application of centralized control technology of generating units.
文摘An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature control systems, and then parameters in the cold load model and in the central air-conditioning system model are estimated. Generalized predictive control (GPC) is used to establish an optimization model to minimize the consumption of energy and the control error of temperature. The simulated annealing (SA) algorithm, combined with quadratic programming, is adopted to solve the optimal problem. Contrasted with the simulation of traditional PID control, the results prove the effectiveness of this proposed strategy.
文摘Software-Defined Networking(SDN)improves network management by separating its control logic from the underlying hardware and integrating it into a logically centralized control unit,termed the SDN controller.SDN adaptation is essential for wireless networks because it offers enhanced and data-intensive services.The initial intent of the SDN design was to have a physically centralized controller.However,network experts have suggested logically centralized and physically distributed designs for SDN controllers,owing to issues such as a single point of failure and scalability.This study addressed the security,scalability,reliability,and consistency issues associated with the design of distributed SDN controllers.Moreover,the security issues of an enterprise related to multiple physically distributed controllers in a software-defined wireless local area network(SD-WLAN)were emphasized,and optimal solutions were suggested.
文摘Mr.Jiang Zcmin,Gencral-Seerctary of the Cen-tral Committee of the Chincse Communist Party and.Chairman of the People's Republic of China,in a rC-ccnt spcech cm phasized that the family planning pro-gramme should be strictly and effectively im plemented in 1994,a year of crucial importance for promoting re-form and opening and thc drive lowards.modernization.To makc continucd contributions to the sociocconomic development in the country,we must fulfil the plan for controlling population growth..The spcech was delivcred at the anua!National Fo-rum on Family Planning Work convened jointly by the Party's Central Committcc and the Statc Council.
文摘A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to discuss the design of fuzzy controller using common microprogrammed control unit (MCU) in detail. Based on fuzzy theory the query control tables fixed in read only memory (ROM) of MCU are established to realize the energy saving in the room temperature controller and the reasoning procedure is analyzed. The diagram of hardware design and the flow chart of software of room temperature controller are presented. The results show that the proposed method is practical and effective to achieve the energy saving goal.
文摘The alternative energy resources, like solar, are always complementary due to environmental changes. Energy generation with the sources such as solar and wind is gaining importance and of that photovoltaic conversion is the main focus of researches due to its promising potential as the electrical source. This paper presents the constant voltage method of control where the output of the converter is maintained constant irrespective of the variations in the irradiance with the high step-up isolated efficient single switch DC-DC converter for the solar PV systems. Constant voltage method of control uses the array of photovoltaic systems as its energy source. The output of the Solar PV systems is nonlinear and has its dependency on temperature and irradiance by which the panel voltage and current varies with the variation in irradiance. Constant voltage control method always operates in such a way that the converter voltage is tried to be maintained constantly to the reference voltage which is set by the user. The system used here utilizes high step single switch isolated DC-DC converter and monitors the voltage continuously by varying the duty cycle to maintain the converter voltage always constant. As a way of improving the performance, both the open and closed loop analysis is done where the closed loop analysis uses the PI controller for its performance. The model is implemented in MATLAB and it accepts the irradiance as the input and outputs the constant voltage from the converter and the feasibility of the proposed converter topology is confirmed with experimental results of the prototype model.
