The distribution control center(DCC)has evolved from a sideshow in the traditional distribution service center to a major centerpiece of the utility moving into the decentralized world.Mostly,this is the place where m...The distribution control center(DCC)has evolved from a sideshow in the traditional distribution service center to a major centerpiece of the utility moving into the decentralized world.Mostly,this is the place where much of the action is happening due to new forms of energy that are coining into the distribution system.This creates the flexibility of operation and in-creased complexity due to the need for increased coordination between the transmission control center and DCC.However,the US and European utilities have adapted to this change in very different ways.Firstly,we describe the research works done in a DCC and their evolutions from the perspectives of major US utilities,and those enhanced by the European perspective focusing on the coordination of distribution system operator and transmission system operator(DSO-TSO).We pres-ent the insights into the systems used in these control centers and the role of vendors in their evolution.Throughout this paper,we present the perspectives of challenges,operational capabilities,and the involvement of various parties who will be re-sponsible to make the transition successful.Key differences are pointed out on how distribution operations are conducted between the US and Europe.展开更多
With the simultaneous rise of energy costs and demand for cloud computing, efficient control of data centers becomes crucial. In the data center control problem, one needs to plan at every time step how many servers t...With the simultaneous rise of energy costs and demand for cloud computing, efficient control of data centers becomes crucial. In the data center control problem, one needs to plan at every time step how many servers to switch on or off in order to meet stochastic job arrivals while trying to minimize electricity consumption. This problem becomes particularly challenging when servers can be of various types and jobs from different classes can only be served by certain types of server, as it is often the case in real data centers. We model this problem as a robust Markov decision process(i.e., the transition function is not assumed to be known precisely). We give sufficient conditions(which seem to be reasonable and satisfied in practice) guaranteeing that an optimal threshold policy exists. This property can then be exploited in the design of an efficient solving method, which we provide.Finally, we present some experimental results demonstrating the practicability of our approach and compare with a previous related approach based on model predictive control.展开更多
Fast and high fidelity quantum control is the key technology of quantum computing. The hybrid system composed of the nitrogen-vacancy center and nearby Carbon-13 nuclear spin is expected to solve this problem. The nit...Fast and high fidelity quantum control is the key technology of quantum computing. The hybrid system composed of the nitrogen-vacancy center and nearby Carbon-13 nuclear spin is expected to solve this problem. The nitrogen-vacancy center electron spin enables fast operations for its strong coupling to the control field, whereas the nuclear spins preserve the coherence for their weak coupling to the environment. In this paper, we describe a strategy to achieve time-optimal control of the Carbon-13 nuclear spin qubit by alternating controlling the nitrogen-vacancy center electron spin as an actuator. We transform the qubit gate operation into a switched system. By using the maximum principle, we study the minimum time control of the switched system and obtain the time-optimal control of the qubit gate operation. We show that the X gate and Y gate operations are within 10μs while the fidelity reaches 0.995.展开更多
The Adaptive Quality Control Phantom (AQCP) is a computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produc...The Adaptive Quality Control Phantom (AQCP) is a computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce a spatial distribution of gamma rays to perform QC Tests such as the Collimator Hole Angulation (CHA) and the Center of Rotation (COR) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for six collimators was measured using a point source and a computer-controlled cylindrical positioning system. In this method, the displacement of the image of a point source was examined as the AQCP was moving point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS and LEUHR collimators of SMV dual heads camera and LEGP, MEGP and HEGP of GE Millennium MG were evaluated to be 0.290°, 0.292°, 0.208°, 0.154°, 0.220° and 0.202°, respectively. It is to be added in this connection that the evaluated RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface ±1 mm has been varied ±0.04 degree. A new method for the center of rotation assessment by AQCP is introduced and the results of this proposed method as compared with the routine QC test and their differences are discussed in detail. We defined and measured a new parameter called Dynamic Mechanical Error (DME) for applying the gantry motion correction.展开更多
无损以太网对于数据中心网络有着很强的吸引力,如今为了实现无损这一目的,诞生了很多新的拥塞控制协议如Data Center TCP(DCTCP)、Quantized Congestion Notification(QCN)、Data Center Quantized Congestion Notification(DCQCN)等。...无损以太网对于数据中心网络有着很强的吸引力,如今为了实现无损这一目的,诞生了很多新的拥塞控制协议如Data Center TCP(DCTCP)、Quantized Congestion Notification(QCN)、Data Center Quantized Congestion Notification(DCQCN)等。对DCTCP、DCQCN等拥塞控制算法进行仿真实验,分析不同的拥塞控制在数据中心网络模型中应对大量突发流的情况,并分析其中存在的拥塞扩散、发送源阻塞、死锁等问题。针对这些问题进行改进,提出融合控制拥塞通知(Fusion Control Congestion Notification,FCCN),以改善拥塞扩散和死锁问题,减少了拥塞控制的吞吐量损失。多次仿真结果表明提出的FCCN方法在不丢包的情况下应对的突发流达到DCTCP的1.5倍,同时突发流对于整个网络吞吐量的下降减少了20%,延迟减少了25%。展开更多
Key technologies as well as their principles were discussed for a decentralized control platform capable of dynamic evolution. The primary content includes the automatic decision-making mechanism and the algorithm of ...Key technologies as well as their principles were discussed for a decentralized control platform capable of dynamic evolution. The primary content includes the automatic decision-making mechanism and the algorithm of the control center migration, the principle and technology of system self-monitoring, the principle and technology of the switch-mode of remote control station, the information transmission technology, and the data consistency technology. These key technologies have shown a series of advanced characteristics for decentralized control platform.展开更多
基金MONKS,Sarajevo,FBiH,Bosnia and Herzegovina(No.27-02-11-41250-34/21).
文摘The distribution control center(DCC)has evolved from a sideshow in the traditional distribution service center to a major centerpiece of the utility moving into the decentralized world.Mostly,this is the place where much of the action is happening due to new forms of energy that are coining into the distribution system.This creates the flexibility of operation and in-creased complexity due to the need for increased coordination between the transmission control center and DCC.However,the US and European utilities have adapted to this change in very different ways.Firstly,we describe the research works done in a DCC and their evolutions from the perspectives of major US utilities,and those enhanced by the European perspective focusing on the coordination of distribution system operator and transmission system operator(DSO-TSO).We pres-ent the insights into the systems used in these control centers and the role of vendors in their evolution.Throughout this paper,we present the perspectives of challenges,operational capabilities,and the involvement of various parties who will be re-sponsible to make the transition successful.Key differences are pointed out on how distribution operations are conducted between the US and Europe.
文摘With the simultaneous rise of energy costs and demand for cloud computing, efficient control of data centers becomes crucial. In the data center control problem, one needs to plan at every time step how many servers to switch on or off in order to meet stochastic job arrivals while trying to minimize electricity consumption. This problem becomes particularly challenging when servers can be of various types and jobs from different classes can only be served by certain types of server, as it is often the case in real data centers. We model this problem as a robust Markov decision process(i.e., the transition function is not assumed to be known precisely). We give sufficient conditions(which seem to be reasonable and satisfied in practice) guaranteeing that an optimal threshold policy exists. This property can then be exploited in the design of an efficient solving method, which we provide.Finally, we present some experimental results demonstrating the practicability of our approach and compare with a previous related approach based on model predictive control.
基金This work was supported by the National Natural Science Foundation of China （Nos. 61227902, 61573343） and the National Center for Mathematics and Interdisciplinary Sciences, CAS.
文摘Fast and high fidelity quantum control is the key technology of quantum computing. The hybrid system composed of the nitrogen-vacancy center and nearby Carbon-13 nuclear spin is expected to solve this problem. The nitrogen-vacancy center electron spin enables fast operations for its strong coupling to the control field, whereas the nuclear spins preserve the coherence for their weak coupling to the environment. In this paper, we describe a strategy to achieve time-optimal control of the Carbon-13 nuclear spin qubit by alternating controlling the nitrogen-vacancy center electron spin as an actuator. We transform the qubit gate operation into a switched system. By using the maximum principle, we study the minimum time control of the switched system and obtain the time-optimal control of the qubit gate operation. We show that the X gate and Y gate operations are within 10μs while the fidelity reaches 0.995.
文摘The Adaptive Quality Control Phantom (AQCP) is a computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce a spatial distribution of gamma rays to perform QC Tests such as the Collimator Hole Angulation (CHA) and the Center of Rotation (COR) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for six collimators was measured using a point source and a computer-controlled cylindrical positioning system. In this method, the displacement of the image of a point source was examined as the AQCP was moving point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS and LEUHR collimators of SMV dual heads camera and LEGP, MEGP and HEGP of GE Millennium MG were evaluated to be 0.290°, 0.292°, 0.208°, 0.154°, 0.220° and 0.202°, respectively. It is to be added in this connection that the evaluated RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface ±1 mm has been varied ±0.04 degree. A new method for the center of rotation assessment by AQCP is introduced and the results of this proposed method as compared with the routine QC test and their differences are discussed in detail. We defined and measured a new parameter called Dynamic Mechanical Error (DME) for applying the gantry motion correction.
文摘无损以太网对于数据中心网络有着很强的吸引力,如今为了实现无损这一目的,诞生了很多新的拥塞控制协议如Data Center TCP(DCTCP)、Quantized Congestion Notification(QCN)、Data Center Quantized Congestion Notification(DCQCN)等。对DCTCP、DCQCN等拥塞控制算法进行仿真实验,分析不同的拥塞控制在数据中心网络模型中应对大量突发流的情况,并分析其中存在的拥塞扩散、发送源阻塞、死锁等问题。针对这些问题进行改进,提出融合控制拥塞通知(Fusion Control Congestion Notification,FCCN),以改善拥塞扩散和死锁问题,减少了拥塞控制的吞吐量损失。多次仿真结果表明提出的FCCN方法在不丢包的情况下应对的突发流达到DCTCP的1.5倍,同时突发流对于整个网络吞吐量的下降减少了20%,延迟减少了25%。
基金The National Innovation Fund ( No.00C262251211336)
文摘Key technologies as well as their principles were discussed for a decentralized control platform capable of dynamic evolution. The primary content includes the automatic decision-making mechanism and the algorithm of the control center migration, the principle and technology of system self-monitoring, the principle and technology of the switch-mode of remote control station, the information transmission technology, and the data consistency technology. These key technologies have shown a series of advanced characteristics for decentralized control platform.
