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
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
Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multiv...Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.展开更多
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
Objective:To analyze the effect of quality control circle on the central sterile supply department(CSSD).Methods:The control group and the observation group each consisted of 180 instruments received by the sterilizat...Objective:To analyze the effect of quality control circle on the central sterile supply department(CSSD).Methods:The control group and the observation group each consisted of 180 instruments received by the sterilization supply center from January to March 2023 and 11 CSSD staff.The control group underwent routine management while quality control circle was implemented in the observation group.The quality of work,disinfection and sterilization qualification rates,disinfection and sterilization of various instruments,cleaning indicators,and management satisfaction of both groups were compared.Results:The observation group scored higher in terms of work quality,the qualification rate of disinfection and sterilization in each link,the disinfection and sterilization of instruments,and cleaning indicators compared to the control group.Besides,the management satisfaction of the observation group was higher than that of the control group(P<0.05).Conclusion:A quality control circle ensures the quality of work,improves the cleaning,disinfection,and sterilization of instruments of the CSSD,and improves the management satisfaction of the CSSD staff.展开更多
Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipmen...Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipment is necessary. But it is difficult to evaluate it reasonably and comprehensively due to its complexity. A "holistic" approach was discussed to evaluate the energy performance of central air-conditioning system for an extra-large commercial building in a subtropical city. All procedures were described in detail, including field investigation method, field measurement instruments, data processing and data analyzing. The main factors affecting energy consumption of air-conditioning system were analyzed and the annual cooling-energy use intensity of this building was calculated and also compared with other shopping malls and other types of buildings in Guangzhou. And COP(coefficient of performance) of chiller, water transfer factor of chilled water system and cooling water system were taken into consideration. At last, the thermal comfort and indoor air quality issues were addressed. The results show that the chilled water pumps are over-sized and the indoor environmental quality should be improved. The purpose of this work is to provide reference for energy performance assessment method for air-conditioning system.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
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
With the rapid development of Virtual Private Network (VPN), many companies and organizations use VPN to implement their private communication. Traditionally, VPN uses security protocols to protect the confidentiality...With the rapid development of Virtual Private Network (VPN), many companies and organizations use VPN to implement their private communication. Traditionally, VPN uses security protocols to protect the confidentiality of data, the message integrity and the endpoint authentication. One core technique of VPN is tunneling, by which clients can access the in- ternal servers traversing VPN. However, the tunneling technique also introduces a concealed security hole. It is possible that if one vicious user can establish tunneling by the VPN server, he can compromise the internal servers behind the VPN server. So this paper presents a novel Application-layer based Centralized Information Access Control (ACIAC) for VPN to solve this problem. To implement an efficient, flexible and multi-decision access control model, we present two key techniques to ACIAC—the centralized management mechanism and the stream-based access control. Firstly, we implement the information center and the constraints/events center for ACIAC. By the two centers, we can provide an abstract access control mechanism, and the material access control can be decided dynamically by the ACIAC’s constraint/event mechanism. Then we logically classify the VPN communication traffic into the access stream and the data stream so that we can tightly couple the features of VPN communication with the access control model. We also provide the design of our ACIAC prototype in this paper.展开更多
Taking the tight oil of the Zhongnan sag in the Ordos Basin,Jimusar sag in the Junggar Basin and Qingxi sag in the Jiuquan Basin as study objects,based on field survey,dissection of tight oil reservoirs,sample test,mo...Taking the tight oil of the Zhongnan sag in the Ordos Basin,Jimusar sag in the Junggar Basin and Qingxi sag in the Jiuquan Basin as study objects,based on field survey,dissection of tight oil reservoirs,sample test,modeling experiment and comprehensive analysis,this study reveals that the tight oil accumulates at start-up pressure,advances under differential pressure,diffuses at alternating fast and low speeds,charges in stepped large area and migrates rapidly through fractures,and enriches in dominant fractures and pores.The root cause of ladder-like charge is the multiple scales of pores.The widespread source rock with high hydrocarbon generation intensity is the material basis for tight oil enrichment;the dominant source reservoir assemblage is the basic unit for tight oil enrichment;fractures and beddings are conducive to local rapid migration of tight oil;fractures and pores work together to control the enrichment of tight oil.Two typical accumulation models of tight oil are established,namely"source reservoir in coexistence,four optimal factors controlling enrichment around central area,and large-scale continuous distribution"for a large freshwater lake clastic rock basin and"source reservoir integration,four optimal factors controlling enrichment,central area distribution,small in size but high in enrichment degree"for a small saline lake diamictite depression.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
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 stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time de...The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.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
[Objectives]This study was conducted to clarify the occurrence of weeds,and give relevant comprehensive control suggestions accordingly.[Methods]The species and community characteristics of weeds in abandoned rice fie...[Objectives]This study was conducted to clarify the occurrence of weeds,and give relevant comprehensive control suggestions accordingly.[Methods]The species and community characteristics of weeds in abandoned rice fields in central Hunan were investigated and analyzed.[Results]There were 75 species of weeds in the abandoned farmland in central Hunan,belonging to 66 genera,27 families.Among them,22 species had a relative abundance of more than 5%.According to the different water environments of abandoned fields,there were differences in the types and structures of weeds.They succeeded to wetland vegetation types and dryland vegetation types respectively.Species grown in the original farmland still exist in abandoned fields,but they were mainly invaded by field weeds,such as Digitaria sanguinalis,Eleusine indica,Panicum acroanthum,Bidens pilosa,and Xanthium sibiricum.[Conclusions]This study lays a foundation for fully guaranteeing the actual results of re-cultivation of abandoned land in rural areas.展开更多
Objective:To uncover the impact of centralization of COVID-19 and perceived control of COVID-19 on society during the pandemic.Methods:We recruited a total of 1041 people in this cross-sectional study.The data were co...Objective:To uncover the impact of centralization of COVID-19 and perceived control of COVID-19 on society during the pandemic.Methods:We recruited a total of 1041 people in this cross-sectional study.The data were collected using a questionnaire booklet covering demographics,a COVID-19-related information form,the Centrality of Event Scale,and the Perception of Control of COVID-19 Scale.We utilized independent samples t-test,chi-square test,and one-way analysis of variance to analyze the data.Results:1041 questionnaires were collected and no questionnaire were excluded from our study.Slightly more than half of the participants(51.2%)stated that social isolation impaired public mental health,while 30.1%reported adverse impacts of the pandemic on their sleep quality.Participants with changes to their sleep patterns were found to centralize COVID-19 more.Moreover,measures against COVID-19 and constant announcements of the daily number of cases in the media brought both positive and negative effects on people and further contributed to the participants’centralization of COVID-19.Individuals with low centralization scores were concluded to perceive COVID-19 as a minor disease.Healthcare professionals without a relative diagnosed with COVID-19 and those satisfied with treatment opportunities had a higher perceived control of COVID-19,while those who were not interested in statistical data on COVID-19 and who had difficulty complying with the rules had a lower perceived control of COVID-19.Besides,poorer perceived control of COVID-19 was found to adversely affect sleep quality.Furthermore,healthcare professionals scored higher on the inevitability subscale of the Perception of Control of COVID-19 Scale.Finally,among the participants,most COVID-19 survivors thought COVID-19 to be an avoidable disease.Conclusion:In addition to its physical impacts,COVID-19 adversely impacts on mental health,and these effects are closely linked to a society’s centralization of COVID-19 and perceived control of COVID-19.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
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
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
With the explosive increasing number of connecting devices such as smart phones, vehicles,drones, and satellites in the wireless networks, how to manage and control such a huge number of networking nodes has become a ...With the explosive increasing number of connecting devices such as smart phones, vehicles,drones, and satellites in the wireless networks, how to manage and control such a huge number of networking nodes has become a great challenge. In this paper, we combine the advantages of centralized networks and distributed networks approaches for vehicular networks with the aid of Unmanned Aerial Vehicle(UAV), and propose a Center-controlled Multihop Wireless(CMW) networking scheme consisting of data transmission plane performed by vehicles and the network control plane implemented by the UAV.Besides, we jointly explore the advantages of Medium Access Control(MAC) protocols in the link layer and routing schemes in the network layer to facilitate the multi-hop data transmission for the ground vehicles.Particularly, the network control plane in the UAV can manage the whole network effectively via fully exploiting the acquired network topology information and traffic requests from each vehicle, and implements various kinds of control based on different traffic demands, which can enhance the networking flexibility and scalability significantly in vehicular networks.Simulation results validate the advantages of the proposed scheme compared with existing methods.展开更多
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.
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.
基金Supported by Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education of China
文摘Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.
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.
文摘Objective:To analyze the effect of quality control circle on the central sterile supply department(CSSD).Methods:The control group and the observation group each consisted of 180 instruments received by the sterilization supply center from January to March 2023 and 11 CSSD staff.The control group underwent routine management while quality control circle was implemented in the observation group.The quality of work,disinfection and sterilization qualification rates,disinfection and sterilization of various instruments,cleaning indicators,and management satisfaction of both groups were compared.Results:The observation group scored higher in terms of work quality,the qualification rate of disinfection and sterilization in each link,the disinfection and sterilization of instruments,and cleaning indicators compared to the control group.Besides,the management satisfaction of the observation group was higher than that of the control group(P<0.05).Conclusion:A quality control circle ensures the quality of work,improves the cleaning,disinfection,and sterilization of instruments of the CSSD,and improves the management satisfaction of the CSSD staff.
基金Project(2011B061200043)supported by the Guangdong Provincial Department of Science and Technology,China
文摘Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipment is necessary. But it is difficult to evaluate it reasonably and comprehensively due to its complexity. A "holistic" approach was discussed to evaluate the energy performance of central air-conditioning system for an extra-large commercial building in a subtropical city. All procedures were described in detail, including field investigation method, field measurement instruments, data processing and data analyzing. The main factors affecting energy consumption of air-conditioning system were analyzed and the annual cooling-energy use intensity of this building was calculated and also compared with other shopping malls and other types of buildings in Guangzhou. And COP(coefficient of performance) of chiller, water transfer factor of chilled water system and cooling water system were taken into consideration. At last, the thermal comfort and indoor air quality issues were addressed. The results show that the chilled water pumps are over-sized and the indoor environmental quality should be improved. The purpose of this work is to provide reference for energy performance assessment method for air-conditioning system.
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.
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Project (No. 60373088) supported by the National Natural ScienceFoundation of China
文摘With the rapid development of Virtual Private Network (VPN), many companies and organizations use VPN to implement their private communication. Traditionally, VPN uses security protocols to protect the confidentiality of data, the message integrity and the endpoint authentication. One core technique of VPN is tunneling, by which clients can access the in- ternal servers traversing VPN. However, the tunneling technique also introduces a concealed security hole. It is possible that if one vicious user can establish tunneling by the VPN server, he can compromise the internal servers behind the VPN server. So this paper presents a novel Application-layer based Centralized Information Access Control (ACIAC) for VPN to solve this problem. To implement an efficient, flexible and multi-decision access control model, we present two key techniques to ACIAC—the centralized management mechanism and the stream-based access control. Firstly, we implement the information center and the constraints/events center for ACIAC. By the two centers, we can provide an abstract access control mechanism, and the material access control can be decided dynamically by the ACIAC’s constraint/event mechanism. Then we logically classify the VPN communication traffic into the access stream and the data stream so that we can tightly couple the features of VPN communication with the access control model. We also provide the design of our ACIAC prototype in this paper.
基金Supported by the National Natural Science Foundation of China(41672118)Strategic Cooperation Science and Technology Project Between China University of Petroleum and Petro China(ZLZX2020-01-06)。
文摘Taking the tight oil of the Zhongnan sag in the Ordos Basin,Jimusar sag in the Junggar Basin and Qingxi sag in the Jiuquan Basin as study objects,based on field survey,dissection of tight oil reservoirs,sample test,modeling experiment and comprehensive analysis,this study reveals that the tight oil accumulates at start-up pressure,advances under differential pressure,diffuses at alternating fast and low speeds,charges in stepped large area and migrates rapidly through fractures,and enriches in dominant fractures and pores.The root cause of ladder-like charge is the multiple scales of pores.The widespread source rock with high hydrocarbon generation intensity is the material basis for tight oil enrichment;the dominant source reservoir assemblage is the basic unit for tight oil enrichment;fractures and beddings are conducive to local rapid migration of tight oil;fractures and pores work together to control the enrichment of tight oil.Two typical accumulation models of tight oil are established,namely"source reservoir in coexistence,four optimal factors controlling enrichment around central area,and large-scale continuous distribution"for a large freshwater lake clastic rock basin and"source reservoir integration,four optimal factors controlling enrichment,central area distribution,small in size but high in enrichment degree"for a small saline lake diamictite depression.
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 stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.
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.
基金Scientific Research Fund of Hunan Provincial Education Department(18B461)Scientific Research Fund of Hunan Provincial Science and Technology Innovation Plan Project(2019NK4170).
文摘[Objectives]This study was conducted to clarify the occurrence of weeds,and give relevant comprehensive control suggestions accordingly.[Methods]The species and community characteristics of weeds in abandoned rice fields in central Hunan were investigated and analyzed.[Results]There were 75 species of weeds in the abandoned farmland in central Hunan,belonging to 66 genera,27 families.Among them,22 species had a relative abundance of more than 5%.According to the different water environments of abandoned fields,there were differences in the types and structures of weeds.They succeeded to wetland vegetation types and dryland vegetation types respectively.Species grown in the original farmland still exist in abandoned fields,but they were mainly invaded by field weeds,such as Digitaria sanguinalis,Eleusine indica,Panicum acroanthum,Bidens pilosa,and Xanthium sibiricum.[Conclusions]This study lays a foundation for fully guaranteeing the actual results of re-cultivation of abandoned land in rural areas.
文摘Objective:To uncover the impact of centralization of COVID-19 and perceived control of COVID-19 on society during the pandemic.Methods:We recruited a total of 1041 people in this cross-sectional study.The data were collected using a questionnaire booklet covering demographics,a COVID-19-related information form,the Centrality of Event Scale,and the Perception of Control of COVID-19 Scale.We utilized independent samples t-test,chi-square test,and one-way analysis of variance to analyze the data.Results:1041 questionnaires were collected and no questionnaire were excluded from our study.Slightly more than half of the participants(51.2%)stated that social isolation impaired public mental health,while 30.1%reported adverse impacts of the pandemic on their sleep quality.Participants with changes to their sleep patterns were found to centralize COVID-19 more.Moreover,measures against COVID-19 and constant announcements of the daily number of cases in the media brought both positive and negative effects on people and further contributed to the participants’centralization of COVID-19.Individuals with low centralization scores were concluded to perceive COVID-19 as a minor disease.Healthcare professionals without a relative diagnosed with COVID-19 and those satisfied with treatment opportunities had a higher perceived control of COVID-19,while those who were not interested in statistical data on COVID-19 and who had difficulty complying with the rules had a lower perceived control of COVID-19.Besides,poorer perceived control of COVID-19 was found to adversely affect sleep quality.Furthermore,healthcare professionals scored higher on the inevitability subscale of the Perception of Control of COVID-19 Scale.Finally,among the participants,most COVID-19 survivors thought COVID-19 to be an avoidable disease.Conclusion:In addition to its physical impacts,COVID-19 adversely impacts on mental health,and these effects are closely linked to a society’s centralization of COVID-19 and perceived control of COVID-19.
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.
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.
基金supported in part by the National Natural Science Foundation of China under Grant 62071283,Grant 61771296,Grant 61872228 and Grant 62271513in part by the Natural Science Basic Research Plan in Shaanxi Province of China under Grant 2018JQ6048 and Grant 2018JZ6006+3 种基金in part by Shaanxi Key Industrial Innovation Chain Project in Industrial Domain under Grant 2020ZDLGY15-09in part by Guang Dong Basic and Applied Basic Research Foundation under Grant 2021A1515012631in part by China Postdoctoral Science Foundation under Grant 2016M600761in part by the Fundamental Research Funds for the Central Universities under Grant GK202003075 and Grant GK202103016。
文摘With the explosive increasing number of connecting devices such as smart phones, vehicles,drones, and satellites in the wireless networks, how to manage and control such a huge number of networking nodes has become a great challenge. In this paper, we combine the advantages of centralized networks and distributed networks approaches for vehicular networks with the aid of Unmanned Aerial Vehicle(UAV), and propose a Center-controlled Multihop Wireless(CMW) networking scheme consisting of data transmission plane performed by vehicles and the network control plane implemented by the UAV.Besides, we jointly explore the advantages of Medium Access Control(MAC) protocols in the link layer and routing schemes in the network layer to facilitate the multi-hop data transmission for the ground vehicles.Particularly, the network control plane in the UAV can manage the whole network effectively via fully exploiting the acquired network topology information and traffic requests from each vehicle, and implements various kinds of control based on different traffic demands, which can enhance the networking flexibility and scalability significantly in vehicular networks.Simulation results validate the advantages of the proposed scheme compared with existing methods.