The reliability analysis of vertically integrated protection devices is crucial for designing International Electrotechnical Commission(IEC)61850-based substations.This paper presents the hardware architecture of a fo...The reliability analysis of vertically integrated protection devices is crucial for designing International Electrotechnical Commission(IEC)61850-based substations.This paper presents the hardware architecture of a four-inone vertically integrated device and the information transmission path of each function based on the functional information transmission chain of protection devices,measurement and control devices,merging units,and intelligent terminals.Additionally,a reliability analysis model of the protection device and its protection system is constructed using the fault tree analysis method while considering the characteristics of each module of the vertically integrated device.The stability probability of the protection system in each state is analyzed by combining the state-transfer equations of line and busbar protection with a Markov chain.Finally,the failure rate and availability of the protection device and its protection system are calculated under different ambient temperatures using a 110 kV intelligent substation as an example.The sensitivity of each device module is analyzed.展开更多
This study aims to investigate and explore the relationship between vertical integration and the firm's innovativeness in food supply chain. For doing so, a two-stage least-squares model was used. It encompassed inst...This study aims to investigate and explore the relationship between vertical integration and the firm's innovativeness in food supply chain. For doing so, a two-stage least-squares model was used. It encompassed instrumental variables that attempt to describe the effective determinants of firm's vertical integration willingness. Results based on data concerning a set of 130 food-manufacturing firms, highlighted that vertical integration of a firm is strongly affected by internal incentives such as innovation rate and firm size. Moreover, it is simultaneously influenced by the economies of scale and some structure incentives. To conclude, results indicate globally that important and statistically significant differences exist across the studied firms and the small effective ones which acquire a high level of vertical integration.展开更多
The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between ...The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region.展开更多
This paper discusses some aspects of interdisciplinary problems of industrial automation curriculum in Virumaa College of Tallinn University of Technology at engineering level. The problems being faced by engineers ar...This paper discusses some aspects of interdisciplinary problems of industrial automation curriculum in Virumaa College of Tallinn University of Technology at engineering level. The problems being faced by engineers are increasingly interdisciplinary and complicated because the development of new products and processes depends upon the integration of many different technologies. Expansion of possibilities of already existing fieldbus systems is carried out by means of integration them into Profinet (PROcess Field NET) communications. The lab set-model of vertical integration-for data gathering from smart Profibus PA sensor, data transmission, controllers configuration for Profinet IO direct interfacing of distributed field devices on the Ethernet is discussed in this paper.展开更多
A novel design of a two-channel optical add-drop multiplexer based on a self-rolled-up microtube (SRM) is presented. This design consists of an SRM that has a parabolic lobe-like pattern along the tube's axial dire...A novel design of a two-channel optical add-drop multiplexer based on a self-rolled-up microtube (SRM) is presented. This design consists of an SRM that has a parabolic lobe-like pattern along the tube's axial direction, as well as straight silicon waveguides and a 180° waveguide bend. The vertical configuration of the SRM and waveguides is analyzed by the coupled mode theory for achieving the optinmm gap. In the critical coupling regime, when the device serves as an optical demultiplexer, the minimum insertion loss is 1.94 dB, and the maximunl channel crosstalk is -6.036 dB. Also, as an optical multiplexer, the maximum crosstalk becomes -11.9 dB.展开更多
[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used ...[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.展开更多
Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle (IODVC) has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludg...Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle (IODVC) has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was low in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0% from 22.3% without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77. 5 % was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21-25 d of SRT. The optimal operational conditions in this study were as follows: recycle rate = 1.5-2.0, COD/TN 〉 6, COD/TP 〉 40, COD loading rate = 0.26-0.32 kgCOD/(kgSS· d), TN loading rate = 0. 028-0. 034 kgTN/( kgSS·d) and TP loading rate = 0.003-0.005 kgTP/(kgSS· d), respectively.展开更多
The spatial and temporal distributions of new production vary largely in different sea areas. To understand the level of new production in the sea area studied better, an estimate of new production must be obtained in...The spatial and temporal distributions of new production vary largely in different sea areas. To understand the level of new production in the sea area studied better, an estimate of new production must be obtained in large spatial and temporal scales. The ~234Th/ ~238U disequilibrium is an effective method for the study of new production. Two sampling strategies, vertically integrated sampling ap proach based on trapezoidal integration principle and discrete layer sampling approach, were compared in the studies of the xiamen Bay and the northern South China Sea. The scavenging fluxes and removal fluxes of ~234Th and the residence times for dissolved and particulate ~234Th were calculated. The coinci dent results from two Sampling approach suggest that vertically integrated sampling approach is not only effective and reliable, but also significantly reduces the number and volume of samples. It allows us to study new production by ba ^(234)Th - ^(238)U disequilibria in large spatial scale.展开更多
The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anoma...The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anomalies with a broad spectrum of sizes and intensities,which arise from geological and tectonic features.The lithospheric magnetic field is known from surface observations,and on larger scales from above-surface measurements.The increase in recent decades of satellites dedicated to measuring the Earth’s magnetic field has improved significantly our models of the Earth’s magnetic environment.Based on these increasing observations,a number of comprehensive field models have been constructed,some of which focus solely on the lithosphere,such as the MF model series.We present a map of lithospheric magnetic anomalies at 400 km altitude,based on a vertically integrated magnetization model.This height was chosen because it is the expected orbital altitude of the Macao Science Satellite-1(MSS-1)mission.The model presented herein indicates that the amplitude of the lithospheric anomalies at 400 km altitude is between-14.8 n T and 18.2 n T.This information is useful because it provides a reference for the lithospheric source of the Earth’s magnetic field that contributes to the magnetic measurements made from satellite instruments.The low inclination orbit of the MSS-1 mission will provide information that is sensitive to lateral variation within the lithosphere;these variations arise from plate tectonic features with longitudinal extent.In conclusion,the new MSS-1mission will provide valuable information in detecting compositional variations in the lithosphere,and in delineating large-scale geological structures.展开更多
The inverse relationship between the warm phase of the El Nino Southern Oscillation(ENSO)and the Indian Summer Monsoon Rainfall(ISMR)is well established.Yet,some El Nino events that occur in the early months of the ye...The inverse relationship between the warm phase of the El Nino Southern Oscillation(ENSO)and the Indian Summer Monsoon Rainfall(ISMR)is well established.Yet,some El Nino events that occur in the early months of the year(boreal spring)transform into a neutral phase before the start of summer,whereas others begin in the boreal summer and persist in a positive phase throughout the summer monsoon season.This study investigates the distinct influences of an exhausted spring El Nino(springtime)and emerging summer El Nino(summertime)on the regional variability of ISMR.The two ENSO categories were formulated based on the time of occurrence of positive SST anomalies over the Nino-3.4 region in the Pacific.The ISMR’s dynamical and thermodynamical responses to such events were investigated using standard metrics such as the Walker and Hadley circulations,vertically integrated moisture flux convergence(VIMFC),wind shear,and upper atmospheric circulation.The monsoon circulation features are remarkably different in response to the exhausted spring El Nino and emerging summer El Nino phases,which distinctly dictate regional rainfall variability.The dynamic and thermodynamic responses reveal that exhausted spring El Nino events favor excess monsoon rainfall over eastern peninsular India and deficit rainfall over the core monsoon regions of central India.In contrast,emerging summer El Nino events negatively impact the seasonal rainfall over the country,except for a few regions along the west coast and northeast India.展开更多
To investigate the optimal retail price and service level in a supply chain under consumer returns, a consumer returns model under the retailer's service provision is built. The optimal decision results and optimal p...To investigate the optimal retail price and service level in a supply chain under consumer returns, a consumer returns model under the retailer's service provision is built. The optimal decision results and optimal profits are obtained in the vertical integration game and the manufacturer Stackelberg game, respectively. Through comparing the optimal profits with service provision with those of no service provision, the boundary conditions that the retailer's service should be provided are derived. The results show that in the manufacturer Stackelberg game, the optimal profit of the retailer and the manufacturer with service is always superior to that of a no service provision. However, in the vertical integration game, the supply chain can only benefit from the service under certain conditions. Finally, through numerical examples, the impacts of the cost for providing services and the consumer return rate on the optimal decisions are analyzed.展开更多
The increased deployment of renewable energy in existing power networks has jeopardized rotational inertia,resulting in system degradation and insta-bility.To address the issue,this paper proposes a demand response st...The increased deployment of renewable energy in existing power networks has jeopardized rotational inertia,resulting in system degradation and insta-bility.To address the issue,this paper proposes a demand response strategy for ensuring the future reliability of the electrical power system.In addition,a modified fuzzy logic control topology-based two-degree-of-freedom(fractional order proportional integral)-tilt derivative controller is designed to regulate the frequency within a demand response framework of a hybrid two-area deregulated power system.The test system includes thermal power plants,renewable energy sources(such as wind,parabolic trough solar thermal plant,biogas),and electric vehicle assets.To adaptively tune the controller’s coefficients,a quasi-opposition-based harris hawks optimization(QOHHO)algorithm is developed.The effectiveness of this algorithm is compared to other optimization algorithms,and the stability of the system is evaluated.The results demonstrate that the designed control algorithm significantly enhances system frequency stability in various scenarios,including uncertainties,physical constraints,and high penetration of renewables,compared to existing work.Additionally,an experimental assessment through OPAL-RT is conducted to verify the practicality of the proposed strategy,considering source and load intermittencies.展开更多
We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured cro...We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.展开更多
The approach to remote sensing of water vapor by using global positioning systems(GPS)is discussed.In order to retrieve the vertical integrated water vapor(IWV)or the precipitable water (PW),the weighted“mean tempera...The approach to remote sensing of water vapor by using global positioning systems(GPS)is discussed.In order to retrieve the vertical integrated water vapor(IWV)or the precipitable water (PW),the weighted“mean temperature”of the atmosphere,T_m would be estimated to the specific area and season.T_m depends on surface temperature,tropospheric temperature profile,and the vertical distribution of water vapor.The surface temperature dependence is borne out by a comparison of T_m and the values of surface temperature T_s using radiosonde profiles of Beijing Station(No.54511)throughout 1992.The analysis of radiosonde profiles spanning a one-year interval(1992)from sites in eastern region of China with a latitude range of 20-50°N and a longitude range of 100-130°E yields the coefficients α and b of a linear regression equation T_m= α+bT_s.展开更多
This study considers the choices of channel structures and information strategies in a supply chain with demand uncertainty.The results show the following:(1)The decentralized channel structure dominates the centraliz...This study considers the choices of channel structures and information strategies in a supply chain with demand uncertainty.The results show the following:(1)The decentralized channel structure dominates the centralized channel structure when the information strategy is given.(2)Information sharing by the downstream rival is always beneficial to the vertically integrated producer but is not necessarily detrimental to itself.In particular,information sharing increases the downstream rival’s profit in the centralized channel structure when the demand signal is relatively accurate.(3)The vertically integrated producer always benefits from the increase in forecast accuracy and the downstream rival may be worse off in some situations,which provides a theoretical ground for the“accuracy trap.”In addition,the discussions of the wholesale price commitment and the uniform pricing contracts show that the wholesale price contracts can influence the information sharing conditions of the downstream rival and the effects of strategic decentralization,eventually influencing the equilibrium strategies of channel members.展开更多
基金supported by the 2020 Infrastructure Engineering Technology Innovation Projectthe“Intelligent Substation”Supporting Technology Research Project(031200WS22200001)。
文摘The reliability analysis of vertically integrated protection devices is crucial for designing International Electrotechnical Commission(IEC)61850-based substations.This paper presents the hardware architecture of a four-inone vertically integrated device and the information transmission path of each function based on the functional information transmission chain of protection devices,measurement and control devices,merging units,and intelligent terminals.Additionally,a reliability analysis model of the protection device and its protection system is constructed using the fault tree analysis method while considering the characteristics of each module of the vertically integrated device.The stability probability of the protection system in each state is analyzed by combining the state-transfer equations of line and busbar protection with a Markov chain.Finally,the failure rate and availability of the protection device and its protection system are calculated under different ambient temperatures using a 110 kV intelligent substation as an example.The sensitivity of each device module is analyzed.
文摘This study aims to investigate and explore the relationship between vertical integration and the firm's innovativeness in food supply chain. For doing so, a two-stage least-squares model was used. It encompassed instrumental variables that attempt to describe the effective determinants of firm's vertical integration willingness. Results based on data concerning a set of 130 food-manufacturing firms, highlighted that vertical integration of a firm is strongly affected by internal incentives such as innovation rate and firm size. Moreover, it is simultaneously influenced by the economies of scale and some structure incentives. To conclude, results indicate globally that important and statistically significant differences exist across the studied firms and the small effective ones which acquire a high level of vertical integration.
文摘The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region.
文摘This paper discusses some aspects of interdisciplinary problems of industrial automation curriculum in Virumaa College of Tallinn University of Technology at engineering level. The problems being faced by engineers are increasingly interdisciplinary and complicated because the development of new products and processes depends upon the integration of many different technologies. Expansion of possibilities of already existing fieldbus systems is carried out by means of integration them into Profinet (PROcess Field NET) communications. The lab set-model of vertical integration-for data gathering from smart Profibus PA sensor, data transmission, controllers configuration for Profinet IO direct interfacing of distributed field devices on the Ethernet is discussed in this paper.
文摘A novel design of a two-channel optical add-drop multiplexer based on a self-rolled-up microtube (SRM) is presented. This design consists of an SRM that has a parabolic lobe-like pattern along the tube's axial direction, as well as straight silicon waveguides and a 180° waveguide bend. The vertical configuration of the SRM and waveguides is analyzed by the coupled mode theory for achieving the optinmm gap. In the critical coupling regime, when the device serves as an optical demultiplexer, the minimum insertion loss is 1.94 dB, and the maximunl channel crosstalk is -6.036 dB. Also, as an optical multiplexer, the maximum crosstalk becomes -11.9 dB.
基金Supported by National Major Science and Technology Projects(2009ZX07317-006)National Major Science and Technology Projects(2009ZX07317-009)~~
文摘[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.
文摘Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle (IODVC) has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was low in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0% from 22.3% without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77. 5 % was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21-25 d of SRT. The optimal operational conditions in this study were as follows: recycle rate = 1.5-2.0, COD/TN 〉 6, COD/TP 〉 40, COD loading rate = 0.26-0.32 kgCOD/(kgSS· d), TN loading rate = 0. 028-0. 034 kgTN/( kgSS·d) and TP loading rate = 0.003-0.005 kgTP/(kgSS· d), respectively.
基金National Natural Science Foundation of China! 49676296National Scientific and Technical Project! 97-926-04-02.
文摘The spatial and temporal distributions of new production vary largely in different sea areas. To understand the level of new production in the sea area studied better, an estimate of new production must be obtained in large spatial and temporal scales. The ~234Th/ ~238U disequilibrium is an effective method for the study of new production. Two sampling strategies, vertically integrated sampling ap proach based on trapezoidal integration principle and discrete layer sampling approach, were compared in the studies of the xiamen Bay and the northern South China Sea. The scavenging fluxes and removal fluxes of ~234Th and the residence times for dissolved and particulate ~234Th were calculated. The coinci dent results from two Sampling approach suggest that vertically integrated sampling approach is not only effective and reliable, but also significantly reduces the number and volume of samples. It allows us to study new production by ba ^(234)Th - ^(238)U disequilibria in large spatial scale.
基金supported by the Macao Foundationby the Preresearch Project on Civil Aerospace Technologies No.D020308/D020303 funded by China National Space Administration+1 种基金by the Macao Science and Technology Development Fund,grant No.0001/2019/A1PF Liu is funded by the Science and Technology Development Fund,Macao SAR(File No.0002/2019/APD)。
文摘The Earth’s“lithosphere”is its outer shell,made up of the Earth’s crust and outermost mantle.The part of the Earth’s magnetic field that originates in the lithosphere consists of a superposition of magnetic anomalies with a broad spectrum of sizes and intensities,which arise from geological and tectonic features.The lithospheric magnetic field is known from surface observations,and on larger scales from above-surface measurements.The increase in recent decades of satellites dedicated to measuring the Earth’s magnetic field has improved significantly our models of the Earth’s magnetic environment.Based on these increasing observations,a number of comprehensive field models have been constructed,some of which focus solely on the lithosphere,such as the MF model series.We present a map of lithospheric magnetic anomalies at 400 km altitude,based on a vertically integrated magnetization model.This height was chosen because it is the expected orbital altitude of the Macao Science Satellite-1(MSS-1)mission.The model presented herein indicates that the amplitude of the lithospheric anomalies at 400 km altitude is between-14.8 n T and 18.2 n T.This information is useful because it provides a reference for the lithospheric source of the Earth’s magnetic field that contributes to the magnetic measurements made from satellite instruments.The low inclination orbit of the MSS-1 mission will provide information that is sensitive to lateral variation within the lithosphere;these variations arise from plate tectonic features with longitudinal extent.In conclusion,the new MSS-1mission will provide valuable information in detecting compositional variations in the lithosphere,and in delineating large-scale geological structures.
基金funding support from the National Monsoon Mission program of the Ministry of Earth Sciences(MoES),New Delhi。
文摘The inverse relationship between the warm phase of the El Nino Southern Oscillation(ENSO)and the Indian Summer Monsoon Rainfall(ISMR)is well established.Yet,some El Nino events that occur in the early months of the year(boreal spring)transform into a neutral phase before the start of summer,whereas others begin in the boreal summer and persist in a positive phase throughout the summer monsoon season.This study investigates the distinct influences of an exhausted spring El Nino(springtime)and emerging summer El Nino(summertime)on the regional variability of ISMR.The two ENSO categories were formulated based on the time of occurrence of positive SST anomalies over the Nino-3.4 region in the Pacific.The ISMR’s dynamical and thermodynamical responses to such events were investigated using standard metrics such as the Walker and Hadley circulations,vertically integrated moisture flux convergence(VIMFC),wind shear,and upper atmospheric circulation.The monsoon circulation features are remarkably different in response to the exhausted spring El Nino and emerging summer El Nino phases,which distinctly dictate regional rainfall variability.The dynamic and thermodynamic responses reveal that exhausted spring El Nino events favor excess monsoon rainfall over eastern peninsular India and deficit rainfall over the core monsoon regions of central India.In contrast,emerging summer El Nino events negatively impact the seasonal rainfall over the country,except for a few regions along the west coast and northeast India.
基金The National Natural Science Foundation of China(No.71171049)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXLX_0122)
文摘To investigate the optimal retail price and service level in a supply chain under consumer returns, a consumer returns model under the retailer's service provision is built. The optimal decision results and optimal profits are obtained in the vertical integration game and the manufacturer Stackelberg game, respectively. Through comparing the optimal profits with service provision with those of no service provision, the boundary conditions that the retailer's service should be provided are derived. The results show that in the manufacturer Stackelberg game, the optimal profit of the retailer and the manufacturer with service is always superior to that of a no service provision. However, in the vertical integration game, the supply chain can only benefit from the service under certain conditions. Finally, through numerical examples, the impacts of the cost for providing services and the consumer return rate on the optimal decisions are analyzed.
文摘The increased deployment of renewable energy in existing power networks has jeopardized rotational inertia,resulting in system degradation and insta-bility.To address the issue,this paper proposes a demand response strategy for ensuring the future reliability of the electrical power system.In addition,a modified fuzzy logic control topology-based two-degree-of-freedom(fractional order proportional integral)-tilt derivative controller is designed to regulate the frequency within a demand response framework of a hybrid two-area deregulated power system.The test system includes thermal power plants,renewable energy sources(such as wind,parabolic trough solar thermal plant,biogas),and electric vehicle assets.To adaptively tune the controller’s coefficients,a quasi-opposition-based harris hawks optimization(QOHHO)algorithm is developed.The effectiveness of this algorithm is compared to other optimization algorithms,and the stability of the system is evaluated.The results demonstrate that the designed control algorithm significantly enhances system frequency stability in various scenarios,including uncertainties,physical constraints,and high penetration of renewables,compared to existing work.Additionally,an experimental assessment through OPAL-RT is conducted to verify the practicality of the proposed strategy,considering source and load intermittencies.
文摘We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.
文摘The approach to remote sensing of water vapor by using global positioning systems(GPS)is discussed.In order to retrieve the vertical integrated water vapor(IWV)or the precipitable water (PW),the weighted“mean temperature”of the atmosphere,T_m would be estimated to the specific area and season.T_m depends on surface temperature,tropospheric temperature profile,and the vertical distribution of water vapor.The surface temperature dependence is borne out by a comparison of T_m and the values of surface temperature T_s using radiosonde profiles of Beijing Station(No.54511)throughout 1992.The analysis of radiosonde profiles spanning a one-year interval(1992)from sites in eastern region of China with a latitude range of 20-50°N and a longitude range of 100-130°E yields the coefficients α and b of a linear regression equation T_m= α+bT_s.
基金supported by the National Social Science Foundation of China[grant number 18BGL106].
文摘This study considers the choices of channel structures and information strategies in a supply chain with demand uncertainty.The results show the following:(1)The decentralized channel structure dominates the centralized channel structure when the information strategy is given.(2)Information sharing by the downstream rival is always beneficial to the vertically integrated producer but is not necessarily detrimental to itself.In particular,information sharing increases the downstream rival’s profit in the centralized channel structure when the demand signal is relatively accurate.(3)The vertically integrated producer always benefits from the increase in forecast accuracy and the downstream rival may be worse off in some situations,which provides a theoretical ground for the“accuracy trap.”In addition,the discussions of the wholesale price commitment and the uniform pricing contracts show that the wholesale price contracts can influence the information sharing conditions of the downstream rival and the effects of strategic decentralization,eventually influencing the equilibrium strategies of channel members.