A new combined model is proposed to obtain predictive data value applied in state estimation for radial power distribution networks. The time delay part of the model is calculated by a recursive least squares algorith...A new combined model is proposed to obtain predictive data value applied in state estimation for radial power distribution networks. The time delay part of the model is calculated by a recursive least squares algorithm of system identification, which can gradually forget past information. The grey series part of the model uses an equal dimension new information model (EDNIM) and it applies 3 points smoothing method to preprocess the original data and modify remnant difference by GM(1,1). Through the optimization of the coefficient of the model, we are able to minimize the error variance of predictive data. A case study shows that the proposed method achieved high calculation precision and speed and it can be used to obtain the predictive value in real time state estimation of power distribution networks.展开更多
In order to solve the problem that traditional energy efficiency power allocation algorithms usually require the assumption of constant or perfect channel state information in cognitive radio networks(CRNs),which may ...In order to solve the problem that traditional energy efficiency power allocation algorithms usually require the assumption of constant or perfect channel state information in cognitive radio networks(CRNs),which may lead to performance degradation in real systems with disturbances or uncertainties,we propose a robust energy efficiency power allocation algorithm for underlay cognitive radio(CR)systems with channel uncertainty in consideration of interference power threshold constraint and minimum target SINR requirement constraint.The ellipsoid sets are used to describe the channel uncertainty,and a constrained fractional programming for the allocation is transformed to a convex optimization problem by worst-case optimization approach.A simplified version of robust energy efficiency scheme by a substitutional constraint having lower complexity is presented.Simulation results show that our proposed scheme can provide higher energy efficiency compared with capacity maximization algorithm and guarantee the signal to interference plus noise ratio(SINR)requirement of each cognitive user under channel uncertainty.展开更多
The small-cell technology is promising for spectral-efficiency enhancement. However, it usually requires a huge amount of energy consumption. In this paper, queue state information and channel state information are jo...The small-cell technology is promising for spectral-efficiency enhancement. However, it usually requires a huge amount of energy consumption. In this paper, queue state information and channel state information are jointly utilized to minimize the time average of overall energy consumption for a multi-carrier small-cell network, where the inter-cell interference is an intractable problem. Based on the Lyapunov optimization theory, the problem could be solved by dynamically optimizing the problem of user assignment, carrier allocation and power allocation in each time slot. As the optimization problem is NP-hard, we propose a heuristic iteration algorithm to solve it. Numerical results verify that the heuristic algorithm offers an approximate performance as the brute-force algorithm. Moreover, it could bring down the overall energy consumption to different degrees according to the variation of traffic load. Meanwhile, it could achieve the same sum rate as the algorithm which focuses on maximizing system sum rate.展开更多
In recent years, realising a ＂clean- state＂ design for the future Internet has become an important research focus. An architecture com- bining an Information-Centric Network （ICN） and Sottware-Defmed Network （SDN...In recent years, realising a ＂clean- state＂ design for the future Internet has become an important research focus. An architecture com- bining an Information-Centric Network （ICN） and Sottware-Defmed Network （SDN） （IC-SDN） has gradually attracted more attention. How- ever, the existing studies regarding IC-SDN still lack support in terms of the ＂network status awareness＂ function, resulting in unreasonable resource allocation. In this paper, we propose a new status-aware resource adaptation sche- me, i.e. a status-aware module is embedded into basic elements （Forwarding Node （FN） and Resource adaption Manager （RM））. The FNs collect the network status dynamically for the controller to reallocate network resources accor- ding to the fluctuations in environmental con- ditions. Simulation results show that, compared with the existing IC-SDN mechanism, the pro- posed scheme reduced the link bandwidth var- iance by 56% and the content delivery latency by 40%. The proof-of-concept implementation demonstrates the feasibility of our proposed sc- heme for small-scale deployment.展开更多
The reflection and transmission characteristics of the guided modes in parallel-plate waveguides partially filled with one or multi chiral rods have been investigated by a method, which combines the multi- mode networ...The reflection and transmission characteristics of the guided modes in parallel-plate waveguides partially filled with one or multi chiral rods have been investigated by a method, which combines the multi- mode network theory with a rigorous mode matching procedure. The formulas of the reflection and transmis- sion coefficient matrix are derived. The numerical results for different cases are presented and have indicated that the chirality parameters and the geometrical dimensions of the chiral rods have significant influence on the reflection and transmission characteristics of the guided modes.展开更多
This paper presents a case study about a condition monitoring project for asset management implementing an advanced decision process for maintenance and asset replacement in the Qatar electricity distribution network....This paper presents a case study about a condition monitoring project for asset management implementing an advanced decision process for maintenance and asset replacement in the Qatar electricity distribution network. It describes the principles used to produce an assessment of the health of the entire fleet of assets, together with the concepts retained to prioritize the interventions on the distribution network equipment. The paper goes through the actual steps taken for the preparation and execution mode of the overall project. It covers the following project phases： definition of the problem ＆ business objectives, process definition and preparation tasks, presentation of solutions and execution phase. The project being still in the implementation phase, the conclusions are preliminary but already demonstrate concrete and tangible benefits.展开更多
文摘A new combined model is proposed to obtain predictive data value applied in state estimation for radial power distribution networks. The time delay part of the model is calculated by a recursive least squares algorithm of system identification, which can gradually forget past information. The grey series part of the model uses an equal dimension new information model (EDNIM) and it applies 3 points smoothing method to preprocess the original data and modify remnant difference by GM(1,1). Through the optimization of the coefficient of the model, we are able to minimize the error variance of predictive data. A case study shows that the proposed method achieved high calculation precision and speed and it can be used to obtain the predictive value in real time state estimation of power distribution networks.
基金supported by the Nation Natural Science Foundation of China(Grant NO.61501059)the Education Department of Jilin Province(Grant NO.2016343)
文摘In order to solve the problem that traditional energy efficiency power allocation algorithms usually require the assumption of constant or perfect channel state information in cognitive radio networks(CRNs),which may lead to performance degradation in real systems with disturbances or uncertainties,we propose a robust energy efficiency power allocation algorithm for underlay cognitive radio(CR)systems with channel uncertainty in consideration of interference power threshold constraint and minimum target SINR requirement constraint.The ellipsoid sets are used to describe the channel uncertainty,and a constrained fractional programming for the allocation is transformed to a convex optimization problem by worst-case optimization approach.A simplified version of robust energy efficiency scheme by a substitutional constraint having lower complexity is presented.Simulation results show that our proposed scheme can provide higher energy efficiency compared with capacity maximization algorithm and guarantee the signal to interference plus noise ratio(SINR)requirement of each cognitive user under channel uncertainty.
基金partially supported by National Basic Research Program of China (2013CB329002)National Natural Science Foundation of China (61631013)+6 种基金The National High Technology Research and Development Program of China(2014AA01A703)Science Fund for Creative Research Groups of NSFC (61321061)National Major Project (2017ZX03001011)International Science and Technology Cooperation Program (2014DFT10320)National Science Foundation of China (61701457 \& 61771286)Tsinghua-Qualcomm Joint Research ProgramHuawei Innovation Research Program
文摘The small-cell technology is promising for spectral-efficiency enhancement. However, it usually requires a huge amount of energy consumption. In this paper, queue state information and channel state information are jointly utilized to minimize the time average of overall energy consumption for a multi-carrier small-cell network, where the inter-cell interference is an intractable problem. Based on the Lyapunov optimization theory, the problem could be solved by dynamically optimizing the problem of user assignment, carrier allocation and power allocation in each time slot. As the optimization problem is NP-hard, we propose a heuristic iteration algorithm to solve it. Numerical results verify that the heuristic algorithm offers an approximate performance as the brute-force algorithm. Moreover, it could bring down the overall energy consumption to different degrees according to the variation of traffic load. Meanwhile, it could achieve the same sum rate as the algorithm which focuses on maximizing system sum rate.
基金supported in part by the National Basic Research Program of China(973 Program)under Grant No.2013CB329100the National Natural Science Foundation of China under Grants No.61232017,No.61271200the Fundamental Research Funds for the Central Universities under Grant No.2013YJS007
文摘In recent years, realising a ＂clean- state＂ design for the future Internet has become an important research focus. An architecture com- bining an Information-Centric Network （ICN） and Sottware-Defmed Network （SDN） （IC-SDN） has gradually attracted more attention. How- ever, the existing studies regarding IC-SDN still lack support in terms of the ＂network status awareness＂ function, resulting in unreasonable resource allocation. In this paper, we propose a new status-aware resource adaptation sche- me, i.e. a status-aware module is embedded into basic elements （Forwarding Node （FN） and Resource adaption Manager （RM））. The FNs collect the network status dynamically for the controller to reallocate network resources accor- ding to the fluctuations in environmental con- ditions. Simulation results show that, compared with the existing IC-SDN mechanism, the pro- posed scheme reduced the link bandwidth var- iance by 56% and the content delivery latency by 40%. The proof-of-concept implementation demonstrates the feasibility of our proposed sc- heme for small-scale deployment.
基金Supported by the National Natural Science Foundation of China (No.60307003, No.60371010) and the Natural Science Foundation of Zhejiang Province (No.602153).
文摘The reflection and transmission characteristics of the guided modes in parallel-plate waveguides partially filled with one or multi chiral rods have been investigated by a method, which combines the multi- mode network theory with a rigorous mode matching procedure. The formulas of the reflection and transmis- sion coefficient matrix are derived. The numerical results for different cases are presented and have indicated that the chirality parameters and the geometrical dimensions of the chiral rods have significant influence on the reflection and transmission characteristics of the guided modes.
文摘This paper presents a case study about a condition monitoring project for asset management implementing an advanced decision process for maintenance and asset replacement in the Qatar electricity distribution network. It describes the principles used to produce an assessment of the health of the entire fleet of assets, together with the concepts retained to prioritize the interventions on the distribution network equipment. The paper goes through the actual steps taken for the preparation and execution mode of the overall project. It covers the following project phases： definition of the problem ＆ business objectives, process definition and preparation tasks, presentation of solutions and execution phase. The project being still in the implementation phase, the conclusions are preliminary but already demonstrate concrete and tangible benefits.
