This paper describes a method for finding the stability regions of the PI and PIP controllers for... more This paper describes a method for finding the stability regions of the PI and PIP controllers for TCP AQM. The method is applied on several representative examples, showing that stable controllers can exhibit widely different performance. Thus, the results highlight the importance of optimizing the design of PI AQM. Furthermore, the paper shows that the previously proposed PIP controller can
The smart power grid will extensively rely on networked control to increase eciency , reli- abili... more The smart power grid will extensively rely on networked control to increase eciency , reli- ability, and safety; to enable plug-and-play asset integration, such as in the case of distributed generation and alternative energy sources; to support market dynamics as well as reduce peak prices and stabilize costs when supply is limited. This paper reviews the major challenges in smart
Proceedings of the Eighth International Workshop on Object-Oriented Real-Time Dependable Systems, 2003. (WORDS 2003)., 2003
... [27] Goldberg Ken and Joseph Santarromana (UC Irvine). The Telegarden http://www.usc.edu/ d... more ... [27] Goldberg Ken and Joseph Santarromana (UC Irvine). The Telegarden http://www.usc.edu/ dept/garden/ , 1995 [28] Ghiasi, Soraya; Zorn, Benjamin. University of Colorado. A Reusable Framework for Web-based Teleoperation of Robotic Devices (June 2000). ...
2012 IEEE Power and Energy Society General Meeting, 2012
ABSTRACT Timely and synchronized phasor data at high resolutions holds great promise for more res... more ABSTRACT Timely and synchronized phasor data at high resolutions holds great promise for more responsible and advanced power grid operations. It is expected that combined effort of developing new application paradigms and the supporting Information and Communication Technology (ICT) will enable the miracle of “Smart Grid” at the transmission level. This paper addresses the design of the supporting ICT system for Wide Area Monitoring and Control applications from the performance perspective. The major contribution that distinguishes this paper from previous research efforts in the same area is that this study quantifies the end-to-end data delay with consideration of different levels of data concentrations. The analysis performed in this paper is not limited to the delay caused by individual ICT components but also provides means to view and analyze the delay of the entire supporting ICT system. Moreover, the quantified delay results drawn in this paper will potentially provide valuable input to the discussion on the coming standards for synchronized phasor measurements.
In this paper, we argue that simulation of Networked Con- trol Systems (NCSs) needs to be carried... more In this paper, we argue that simulation of Networked Con- trol Systems (NCSs) needs to be carried out through co-simulation, which requires the joint and simultaneous simulation of both physical and communication networks dynamics. Co-simulation enables construc- tion of synthetic large-scale networks and workloads, replay of collected traces, and obtaining a complete snapshot of both the network behav- ior and
Fast flux networks represent a special type of botnets that are used to provide highly available ... more Fast flux networks represent a special type of botnets that are used to provide highly available web services to a backend server, which usually hosts malicious content. Detection of fast flux networks continues to be a challenging issue because of the similar behavior between these networks and other legitimate infrastructures, such as CDNs and server farms. This paper proposes Fast Flux Watch (FF-Watch), a mechanism for online detection of fast flux agents. FF-Watch is envisioned to exist as a software agent at leaf routers that connect stub networks to the Internet. The core mechanism of FF-Watch is based on the inherent feature of fast flux networks: flux agents within stub networks take the role of relaying client requests to point-of-sale websites of spam campaigns. The main idea of FF-Watch is to correlate incoming TCP connection requests to flux agents within a stub network with outgoing TCP connection requests from the same agents to the point-of-sale website. Theoretical and traffic trace driven analysis shows that the proposed mechanism can be utilized to efficiently detect fast flux agents within a stub network.
ABSTRACT Synchronized phasor measurement units (PMUs) provide GPS-time tagged, high-sampling rate... more ABSTRACT Synchronized phasor measurement units (PMUs) provide GPS-time tagged, high-sampling rate, positive-sequence voltage and current phasors. When placed in high-voltage substations in power networks, PMUs can provide real-time information that is necessary for the development of Smart Transmission Grid's software applications whose main objective is to improve the power system's monitoring, control and protection. The development of these applications, particularly for use within control centers for on-line purposes, is limited by the availability of and access to real-time PMU data and other information. One attractive approach for application development is the use of real-time simulators to which PMUs can be interfaced as hardware-in-the-loop (HIL) devices to harvest PMU data. However, this approach has technical and economical limitations, which can be tackled by the virtualization of PMU devices. This article describes the development of an entirely software-based synchronized phasor measurement unit for use within real-time simulators to emulate a large number of real-life PMUs, which in turn can be used for creating new phasor-based applications.
2012 IEEE International Energy Conference and Exhibition (ENERGYCON), 2012
ABSTRACT Timely and synchronized phasor data at high resolutions holds a great promise for more r... more ABSTRACT Timely and synchronized phasor data at high resolutions holds a great promise for more responsible and advanced power grid operations. It is expected that the combined effort of developing new application paradigms and the supporting Information and Communication Technology (ICT) will enable the evolutionary change for future transmission grid operation. This paper addresses the design of the supporting ICT system for Wide-Area Monitoring and Control applications considering system performance. The major contribution that distinguishes this paper from previous research efforts in the same area is that this study quantifies the end-to-end data delay and the received packet rate with considerations of different levels of data concentrations. The analysis performed in this paper is not merely limited to the performance issues caused by communication networks but also provides means to view and analyze the overall data delay of the entire supporting ICT system.
ABSTRACT PMU-based Wide Area Monitoring and Control (WAMC) system is introduced to improve the mo... more ABSTRACT PMU-based Wide Area Monitoring and Control (WAMC) system is introduced to improve the monitoring of power grid across large geographic areas and control the grid using more efficient and smart applications. The performance of WAMC applications in real power system scenarios and impact of their supporting Information and Communication Technology (ICT) on the data quality can be quantified and analyzed by pseudo-real co-simulation test beds. The purpose of this study is to propose and develop a WAMC testing platform to facilitate the real-time simulation of dynamic power grid, the ICT infrastructure that overlays the grid and WAMS applications. The platform consists of OPNET, a powerful communication network emulator, connected to a real-time power system simulator through virtualized PMU device. The end point stations such as Phasor Data Concentrator or PMU-based applications are also linked to the platform through OPNET's real-simulation gateway called SITL (System-In-The-Loop). To assess the performance of the platform architecture, a case study has been performed with five PMUs which collect the data from a power model and deliver to PMU-based mode-estimation application over a typical communication network. In this study, the results explicitly intend to quantify the effect of network protocols on data delay.
Tzes et al. present the experimental verification of a mobile client-centric networked control sy... more Tzes et al. present the experimental verification of a mobile client-centric networked control system (NCS) implemented over a General Purpose Radio Service (GPRS) communication channel. The system is set up by defining a client, the controller, which sends information over the network to the server, the plant and actuator. The characteristics of GPRS make the system different from other NCSs studied, which are often implemented over Ethernet or DeviceNet. For security reasons, mobile-phone service providers pre- clude a server from independently sending informa- tion back to the client. In this network, all actions must be initiated by the controller creating a client-centric NCS. The mobile NCS time delays are composed of both encoding/decoding delays and as well the trans- mission times of data through the mobile network. The transmission delays are highly uncertain and depend on a number of factors that include the number of users, loss of packets and the existence of higher priority transmissions. As explained in the paper, GSPR transmissions have a lower priority than GSM-based voice calls. A useful contribution of the paper is the characterization of transmission delays in both UDP and FTP connections through GSPR. The measurements show that the average bit rates are sig- nificantly lower than the theoretical limits of GSPR. The stability of the closed-loop is guaranteed by implementing results from time-delayed systems and by solving a set of linear matrix inequalities. The authors state that the maximum time delay, � max, calculated is conservative. Walsh, et al. (14) present an
This paper describes a method for finding the stability regions of the PI and PIP controllers for... more This paper describes a method for finding the stability regions of the PI and PIP controllers for TCP AQM. The method is applied on several representative examples, showing that stable controllers can exhibit widely different performance. Thus, the results highlight the importance of optimizing the design of PI AQM. Furthermore, the paper shows that the previously proposed PIP controller can
The smart power grid will extensively rely on networked control to increase eciency , reli- abili... more The smart power grid will extensively rely on networked control to increase eciency , reli- ability, and safety; to enable plug-and-play asset integration, such as in the case of distributed generation and alternative energy sources; to support market dynamics as well as reduce peak prices and stabilize costs when supply is limited. This paper reviews the major challenges in smart
Proceedings of the Eighth International Workshop on Object-Oriented Real-Time Dependable Systems, 2003. (WORDS 2003)., 2003
... [27] Goldberg Ken and Joseph Santarromana (UC Irvine). The Telegarden http://www.usc.edu/ d... more ... [27] Goldberg Ken and Joseph Santarromana (UC Irvine). The Telegarden http://www.usc.edu/ dept/garden/ , 1995 [28] Ghiasi, Soraya; Zorn, Benjamin. University of Colorado. A Reusable Framework for Web-based Teleoperation of Robotic Devices (June 2000). ...
2012 IEEE Power and Energy Society General Meeting, 2012
ABSTRACT Timely and synchronized phasor data at high resolutions holds great promise for more res... more ABSTRACT Timely and synchronized phasor data at high resolutions holds great promise for more responsible and advanced power grid operations. It is expected that combined effort of developing new application paradigms and the supporting Information and Communication Technology (ICT) will enable the miracle of “Smart Grid” at the transmission level. This paper addresses the design of the supporting ICT system for Wide Area Monitoring and Control applications from the performance perspective. The major contribution that distinguishes this paper from previous research efforts in the same area is that this study quantifies the end-to-end data delay with consideration of different levels of data concentrations. The analysis performed in this paper is not limited to the delay caused by individual ICT components but also provides means to view and analyze the delay of the entire supporting ICT system. Moreover, the quantified delay results drawn in this paper will potentially provide valuable input to the discussion on the coming standards for synchronized phasor measurements.
In this paper, we argue that simulation of Networked Con- trol Systems (NCSs) needs to be carried... more In this paper, we argue that simulation of Networked Con- trol Systems (NCSs) needs to be carried out through co-simulation, which requires the joint and simultaneous simulation of both physical and communication networks dynamics. Co-simulation enables construc- tion of synthetic large-scale networks and workloads, replay of collected traces, and obtaining a complete snapshot of both the network behav- ior and
Fast flux networks represent a special type of botnets that are used to provide highly available ... more Fast flux networks represent a special type of botnets that are used to provide highly available web services to a backend server, which usually hosts malicious content. Detection of fast flux networks continues to be a challenging issue because of the similar behavior between these networks and other legitimate infrastructures, such as CDNs and server farms. This paper proposes Fast Flux Watch (FF-Watch), a mechanism for online detection of fast flux agents. FF-Watch is envisioned to exist as a software agent at leaf routers that connect stub networks to the Internet. The core mechanism of FF-Watch is based on the inherent feature of fast flux networks: flux agents within stub networks take the role of relaying client requests to point-of-sale websites of spam campaigns. The main idea of FF-Watch is to correlate incoming TCP connection requests to flux agents within a stub network with outgoing TCP connection requests from the same agents to the point-of-sale website. Theoretical and traffic trace driven analysis shows that the proposed mechanism can be utilized to efficiently detect fast flux agents within a stub network.
ABSTRACT Synchronized phasor measurement units (PMUs) provide GPS-time tagged, high-sampling rate... more ABSTRACT Synchronized phasor measurement units (PMUs) provide GPS-time tagged, high-sampling rate, positive-sequence voltage and current phasors. When placed in high-voltage substations in power networks, PMUs can provide real-time information that is necessary for the development of Smart Transmission Grid's software applications whose main objective is to improve the power system's monitoring, control and protection. The development of these applications, particularly for use within control centers for on-line purposes, is limited by the availability of and access to real-time PMU data and other information. One attractive approach for application development is the use of real-time simulators to which PMUs can be interfaced as hardware-in-the-loop (HIL) devices to harvest PMU data. However, this approach has technical and economical limitations, which can be tackled by the virtualization of PMU devices. This article describes the development of an entirely software-based synchronized phasor measurement unit for use within real-time simulators to emulate a large number of real-life PMUs, which in turn can be used for creating new phasor-based applications.
2012 IEEE International Energy Conference and Exhibition (ENERGYCON), 2012
ABSTRACT Timely and synchronized phasor data at high resolutions holds a great promise for more r... more ABSTRACT Timely and synchronized phasor data at high resolutions holds a great promise for more responsible and advanced power grid operations. It is expected that the combined effort of developing new application paradigms and the supporting Information and Communication Technology (ICT) will enable the evolutionary change for future transmission grid operation. This paper addresses the design of the supporting ICT system for Wide-Area Monitoring and Control applications considering system performance. The major contribution that distinguishes this paper from previous research efforts in the same area is that this study quantifies the end-to-end data delay and the received packet rate with considerations of different levels of data concentrations. The analysis performed in this paper is not merely limited to the performance issues caused by communication networks but also provides means to view and analyze the overall data delay of the entire supporting ICT system.
ABSTRACT PMU-based Wide Area Monitoring and Control (WAMC) system is introduced to improve the mo... more ABSTRACT PMU-based Wide Area Monitoring and Control (WAMC) system is introduced to improve the monitoring of power grid across large geographic areas and control the grid using more efficient and smart applications. The performance of WAMC applications in real power system scenarios and impact of their supporting Information and Communication Technology (ICT) on the data quality can be quantified and analyzed by pseudo-real co-simulation test beds. The purpose of this study is to propose and develop a WAMC testing platform to facilitate the real-time simulation of dynamic power grid, the ICT infrastructure that overlays the grid and WAMS applications. The platform consists of OPNET, a powerful communication network emulator, connected to a real-time power system simulator through virtualized PMU device. The end point stations such as Phasor Data Concentrator or PMU-based applications are also linked to the platform through OPNET's real-simulation gateway called SITL (System-In-The-Loop). To assess the performance of the platform architecture, a case study has been performed with five PMUs which collect the data from a power model and deliver to PMU-based mode-estimation application over a typical communication network. In this study, the results explicitly intend to quantify the effect of network protocols on data delay.
Tzes et al. present the experimental verification of a mobile client-centric networked control sy... more Tzes et al. present the experimental verification of a mobile client-centric networked control system (NCS) implemented over a General Purpose Radio Service (GPRS) communication channel. The system is set up by defining a client, the controller, which sends information over the network to the server, the plant and actuator. The characteristics of GPRS make the system different from other NCSs studied, which are often implemented over Ethernet or DeviceNet. For security reasons, mobile-phone service providers pre- clude a server from independently sending informa- tion back to the client. In this network, all actions must be initiated by the controller creating a client-centric NCS. The mobile NCS time delays are composed of both encoding/decoding delays and as well the trans- mission times of data through the mobile network. The transmission delays are highly uncertain and depend on a number of factors that include the number of users, loss of packets and the existence of higher priority transmissions. As explained in the paper, GSPR transmissions have a lower priority than GSM-based voice calls. A useful contribution of the paper is the characterization of transmission delays in both UDP and FTP connections through GSPR. The measurements show that the average bit rates are sig- nificantly lower than the theoretical limits of GSPR. The stability of the closed-loop is guaranteed by implementing results from time-delayed systems and by solving a set of linear matrix inequalities. The authors state that the maximum time delay, � max, calculated is conservative. Walsh, et al. (14) present an
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