A distributed real-time control algorithm for energy storage sharing
- Zhu, Hailing, Ouahada, Khmaies
- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2020
- Subjects: Energy management , Lyapunov optimization , Energy storage sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459635 , uj:40871 , Citation: Zhu, H. & Ouahada, K. 2020. A distributed real-time control algorithm for energy storage sharing.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations and controllable loads in a grid-connected microgrid is studied. In such a microgrid, a group of households, who cooperatively share an energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar energy generations, time-varying load requests and energy contribution to the shared energy storage from all households, as well as delay tolerance of their elastic loads. Exploiting delay tolerance of elastic loads, a joint storage management and load shifting system is present and a distributed online battery sharing control algorithm based on the Lyapunov theory is proposed. The proposed online control algorithm, which provides a suboptimal solution for the joint storage and load shifting problem based only on the current system state, coordinates the utilization of the shared battery among the households in a distributed manner, by jointly optimizing energy charging/discharging and load management for individual households while satisfying each household’s timevarying preference on energy use. Numerical simulation results show that, the proposed load shifting algorithm serves the load demands with a lower delay for each household at a similar average cost per kWh to that of a load shedding algorithm while facilitating a fairer utilization of the shared energy among households.
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- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2020
- Subjects: Energy management , Lyapunov optimization , Energy storage sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459635 , uj:40871 , Citation: Zhu, H. & Ouahada, K. 2020. A distributed real-time control algorithm for energy storage sharing.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations and controllable loads in a grid-connected microgrid is studied. In such a microgrid, a group of households, who cooperatively share an energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar energy generations, time-varying load requests and energy contribution to the shared energy storage from all households, as well as delay tolerance of their elastic loads. Exploiting delay tolerance of elastic loads, a joint storage management and load shifting system is present and a distributed online battery sharing control algorithm based on the Lyapunov theory is proposed. The proposed online control algorithm, which provides a suboptimal solution for the joint storage and load shifting problem based only on the current system state, coordinates the utilization of the shared battery among the households in a distributed manner, by jointly optimizing energy charging/discharging and load management for individual households while satisfying each household’s timevarying preference on energy use. Numerical simulation results show that, the proposed load shifting algorithm serves the load demands with a lower delay for each household at a similar average cost per kWh to that of a load shedding algorithm while facilitating a fairer utilization of the shared energy among households.
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Credit-based distributed real-time energy storage sharing management
- Zhu, Hailing, Ouahada, Khmaies
- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2019
- Subjects: Energy Management , Lyapunov Optimization , Energy Storage Sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/404543 , uj:33930 , Citation: Zhu, H. & Ouahada, K. 2019. Credit-based distributed real-time energy storage sharing management.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations in a grid-connected microgrid is studied. In such a microgrid, a group of households, who are willing to cooperatively operate a shared energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar power generations and the time-varying load demands from all households, as well as the fluctuating electricity prices. This energy management problem, which comprises storage management and load control, is first formulated as a constrained stochastic programming problem. Based on the Lyapunov optimization theory, a distributed real-time sharing control algorithm is proposed to solve the constrained stochastic programming problem without requiring any statistical knowledge of the stochastic renewable energy generations and the uncertain power loads. The credit-based distributed sharing algorithm, in which each household independently solves a simple convex optimization problem without requiring any statistics of the system, is designed to quickly adapt to the system dynamics while facilitating a fair allocation of the shared energy storage with respect to individual households’ energy contributions. The performance gap of the proposed low-complexity distributed sharing algorithm is evaluated via theoretical analysis. Numerical simulations using a practical system setup are conducted to investigate the effectiveness of the proposed sharing control algorithm in terms of energy cost saving and fairness. The simulation results show that the proposed credit-based distributed sharing algorithm can not only save power consumption cost by coordinating the use the shared battery among households in a fair manner but also improve the utilization of renewable energy generation.
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- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2019
- Subjects: Energy Management , Lyapunov Optimization , Energy Storage Sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/404543 , uj:33930 , Citation: Zhu, H. & Ouahada, K. 2019. Credit-based distributed real-time energy storage sharing management.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations in a grid-connected microgrid is studied. In such a microgrid, a group of households, who are willing to cooperatively operate a shared energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar power generations and the time-varying load demands from all households, as well as the fluctuating electricity prices. This energy management problem, which comprises storage management and load control, is first formulated as a constrained stochastic programming problem. Based on the Lyapunov optimization theory, a distributed real-time sharing control algorithm is proposed to solve the constrained stochastic programming problem without requiring any statistical knowledge of the stochastic renewable energy generations and the uncertain power loads. The credit-based distributed sharing algorithm, in which each household independently solves a simple convex optimization problem without requiring any statistics of the system, is designed to quickly adapt to the system dynamics while facilitating a fair allocation of the shared energy storage with respect to individual households’ energy contributions. The performance gap of the proposed low-complexity distributed sharing algorithm is evaluated via theoretical analysis. Numerical simulations using a practical system setup are conducted to investigate the effectiveness of the proposed sharing control algorithm in terms of energy cost saving and fairness. The simulation results show that the proposed credit-based distributed sharing algorithm can not only save power consumption cost by coordinating the use the shared battery among households in a fair manner but also improve the utilization of renewable energy generation.
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Investigating random linear coding from a pricing perspective
- Zhu, Hailing, Ouahada, Khmaies
- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2018
- Subjects: Bulk service , Pricing , Queuing theory
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/282481 , uj:30427 , Citation: Zhu, H. & Ouahada, K. 2018. Investigating random linear coding from a pricing perspective. Entropy 2018, 20, 548; doi:10.3390/e20080548
- Description: Abstract: In this paper, we study the implications of using a form of network coding known as Random Linear Coding (RLC) for unicast communications from an economic perspective by investigating a simple scenario, in which several network nodes, the users, download files from the Internet via another network node, the sender, and the receivers as users pay a certain price to the sender for this service. The mean packet delay for a transmission scheme with RLC is analyzed and applied into an optimal pricing model to characterize the optimal admission rate, price and revenue. The simulation results show that RLC achieves better performance in terms of both mean packet delay and revenue compared to the basic retransmission scheme. Abstract: In this paper, we study the implications of using a form of network coding known as Random Linear Coding (RLC) for unicast communications from an economic perspective by investigating a simple scenario, in which several network nodes, the users, download files from the Internet via another network node, the sender, and the receivers as users pay a certain price to the sender for this service. The mean packet delay for a transmission scheme with RLC is analyzed and applied into an optimal pricing model to characterize the optimal admission rate, price and revenue. The simulation results show that RLC achieves better performance in terms of both mean packet delay and revenue compared to the basic retransmission scheme.
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- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2018
- Subjects: Bulk service , Pricing , Queuing theory
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/282481 , uj:30427 , Citation: Zhu, H. & Ouahada, K. 2018. Investigating random linear coding from a pricing perspective. Entropy 2018, 20, 548; doi:10.3390/e20080548
- Description: Abstract: In this paper, we study the implications of using a form of network coding known as Random Linear Coding (RLC) for unicast communications from an economic perspective by investigating a simple scenario, in which several network nodes, the users, download files from the Internet via another network node, the sender, and the receivers as users pay a certain price to the sender for this service. The mean packet delay for a transmission scheme with RLC is analyzed and applied into an optimal pricing model to characterize the optimal admission rate, price and revenue. The simulation results show that RLC achieves better performance in terms of both mean packet delay and revenue compared to the basic retransmission scheme. Abstract: In this paper, we study the implications of using a form of network coding known as Random Linear Coding (RLC) for unicast communications from an economic perspective by investigating a simple scenario, in which several network nodes, the users, download files from the Internet via another network node, the sender, and the receivers as users pay a certain price to the sender for this service. The mean packet delay for a transmission scheme with RLC is analyzed and applied into an optimal pricing model to characterize the optimal admission rate, price and revenue. The simulation results show that RLC achieves better performance in terms of both mean packet delay and revenue compared to the basic retransmission scheme.
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Oligopolistic competition in heterogeneous access networks under asymmetries of cost and capacity
- Authors: Zhu, Hailing , Nel, Andre
- Date: 2012
- Subjects: Heterogeneous access network , Pricing , Game theory , Oligopolistic competition
- Type: Article
- Identifier: uj:6034 , http://hdl.handle.net/10210/10421
- Description: With the rapid development of broadband wireless access technologies, multiple wireless service provider (WSPs) operating on various wireless access technologies may coexist in one service area to compete for users, leading to a highly competitive environment for the WSPs. In such a competitive heterogeneous wireless access market, different wireless access technologies used by different WSPs have different bandwidth capacities with various costs. In this paper, we set up a noncooperative game model to study how the cost asymmetry and capacity asymmetry among WSPs affect the competition in this market. We first model such a competitive heterogeneous wireless access market as an oligopolistic price competition, in which multiple WSPs compete for a group of price- and delay-sensitive users through their prices, under cost and capacity asymmetries, to maximize their own profits. Then, we develop an analytical framework to investigate whether or not a Nash equilibrium can be achieved among the WSPs in the presence of the cost and capacity asymmetries, how the asymmetries of cost and capacity affect their equilibrium prices and what impact a new WSP with a cost and capacity advantage entering the market has on the equilibrium achieved among existing WSPs.
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- Authors: Zhu, Hailing , Nel, Andre
- Date: 2012
- Subjects: Heterogeneous access network , Pricing , Game theory , Oligopolistic competition
- Type: Article
- Identifier: uj:6034 , http://hdl.handle.net/10210/10421
- Description: With the rapid development of broadband wireless access technologies, multiple wireless service provider (WSPs) operating on various wireless access technologies may coexist in one service area to compete for users, leading to a highly competitive environment for the WSPs. In such a competitive heterogeneous wireless access market, different wireless access technologies used by different WSPs have different bandwidth capacities with various costs. In this paper, we set up a noncooperative game model to study how the cost asymmetry and capacity asymmetry among WSPs affect the competition in this market. We first model such a competitive heterogeneous wireless access market as an oligopolistic price competition, in which multiple WSPs compete for a group of price- and delay-sensitive users through their prices, under cost and capacity asymmetries, to maximize their own profits. Then, we develop an analytical framework to investigate whether or not a Nash equilibrium can be achieved among the WSPs in the presence of the cost and capacity asymmetries, how the asymmetries of cost and capacity affect their equilibrium prices and what impact a new WSP with a cost and capacity advantage entering the market has on the equilibrium achieved among existing WSPs.
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Optimal price subsidy for universal internet service provision
- Zhu, Hailing, Ouahada, Khmaies, Nel, Andre
- Authors: Zhu, Hailing , Ouahada, Khmaies , Nel, Andre
- Date: 2018
- Subjects: Universal service , Subsidy , Social welfare
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/282314 , uj:30410 , Citation: Zhu, H., Ouahada, K. & Nel, A. 2018. Optimal price subsidy for universal internet service provision. Sustainability 2018, 10, 1576; doi:10.3390/su10051576
- Description: Abstract: Abstract: Universal service has been adopted by many countries to bridge the digital divide between Information and communication technologies (ICTs) “haves” and “have-nots”. The key goal of universal service is to provide telecommunications services to “needy persons” at “reasonable” rate. It is, therefore, critical for policymakers to make decisions on what is a “reasonable” price or subsidy for “needy persons” so that the targeted users do utilize ICTs and benefit from them. This paper analyzes universal service subsidies in providing subsidized Internet access from a pricing point of view through a hypothetical scenario where the subsidized users being subsidized through a price subsidyandnon-subsidizeduserssharethesamenetworkoperatedbyaserviceprovider. Wepropose a service differentiation system based on priority queuing to accommodate both groups of users, and model such a system as a Stackelberg game from both a revenue-maximizing service provider perspective and a social welfare maximizing planner’s perspective. We then analyze the optimal prices that maximize the service provider’s revenue and social welfare respectively, investigate how the revenue maximizing price and social welfare maximizing price are effected by users’ willingness to pay and the subsidy ratio, and evaluate the revenue maximizing solution on welfare grounds using the social-maximizing solution as a benchmark. Interestingly, the optimal revenue maximizing solution corresponds to the socially optimal solution in terms of social welfare under the optimum subsidy ratio that maximizes the social welfare. This suggests that the subsidy ratio can be used as a tool to induce the revenue maximizing service provider to set a price that leads to social optimality.
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- Authors: Zhu, Hailing , Ouahada, Khmaies , Nel, Andre
- Date: 2018
- Subjects: Universal service , Subsidy , Social welfare
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/282314 , uj:30410 , Citation: Zhu, H., Ouahada, K. & Nel, A. 2018. Optimal price subsidy for universal internet service provision. Sustainability 2018, 10, 1576; doi:10.3390/su10051576
- Description: Abstract: Abstract: Universal service has been adopted by many countries to bridge the digital divide between Information and communication technologies (ICTs) “haves” and “have-nots”. The key goal of universal service is to provide telecommunications services to “needy persons” at “reasonable” rate. It is, therefore, critical for policymakers to make decisions on what is a “reasonable” price or subsidy for “needy persons” so that the targeted users do utilize ICTs and benefit from them. This paper analyzes universal service subsidies in providing subsidized Internet access from a pricing point of view through a hypothetical scenario where the subsidized users being subsidized through a price subsidyandnon-subsidizeduserssharethesamenetworkoperatedbyaserviceprovider. Wepropose a service differentiation system based on priority queuing to accommodate both groups of users, and model such a system as a Stackelberg game from both a revenue-maximizing service provider perspective and a social welfare maximizing planner’s perspective. We then analyze the optimal prices that maximize the service provider’s revenue and social welfare respectively, investigate how the revenue maximizing price and social welfare maximizing price are effected by users’ willingness to pay and the subsidy ratio, and evaluate the revenue maximizing solution on welfare grounds using the social-maximizing solution as a benchmark. Interestingly, the optimal revenue maximizing solution corresponds to the socially optimal solution in terms of social welfare under the optimum subsidy ratio that maximizes the social welfare. This suggests that the subsidy ratio can be used as a tool to induce the revenue maximizing service provider to set a price that leads to social optimality.
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Resale pricing models for IP-based services over wireless MESH networks
- Authors: Zhu, Hailing
- Date: 2012-06-04
- Subjects: Wireless communication systems , Internet service providers , Internet industry - Prices , Internet rates
- Type: Thesis
- Identifier: uj:2337 , http://hdl.handle.net/10210/4794
- Description: M.Ing. , The development of Wireless Local Area Network (WLAN) technologies offers a novel platform for IP-based service resale via Wireless Mesh Networks (WMNs) that provide high network coverage and lower infrastructure cost. In this IP-based service resale business, the Access Point (AP) providers sets their pricing policies as IP-based service resellers to maximize their profits, while the resale-users (end users of the WMNs) who are price- and quality-of-service (QoS)- sensitive, respond to AP providers’ pricing policies by controlling their usage. This research exploits the efficiency of dynamic pricing by integrating pricing into best effort based WMNs as an economic control tool to optimize the profit of the AP providers and improve the utilization of their limited uplink bandwidth by taking into consideration the resale-users’ price- and QoS- sensitivity. Two cases are presented in this thesis: a monopoly, where a single AP provider aims to maximize its profit while guaranteeing its resale-users with a minimum allocated bandwidth; and a duopoly, where two AP providers compete to maximize their individual profits based on the resale-users’ price- and delay- sensitivity. For both cases, the limited uplink bandwidth of the AP providers is considered as a bottleneck of the WMN. We propose two dynamic pricing models for these two cases respectively and investigate how pricing depends on the assumptions that we make about the market. Indeed, the pricing model proposed for the monopoly is a preliminary study for the duopoly pricing model. In formulating and analyzing these two pricing models, we see how prices are driven by the profit-maximizing aim of one AP provider and the competition between two AP providers.
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- Authors: Zhu, Hailing
- Date: 2012-06-04
- Subjects: Wireless communication systems , Internet service providers , Internet industry - Prices , Internet rates
- Type: Thesis
- Identifier: uj:2337 , http://hdl.handle.net/10210/4794
- Description: M.Ing. , The development of Wireless Local Area Network (WLAN) technologies offers a novel platform for IP-based service resale via Wireless Mesh Networks (WMNs) that provide high network coverage and lower infrastructure cost. In this IP-based service resale business, the Access Point (AP) providers sets their pricing policies as IP-based service resellers to maximize their profits, while the resale-users (end users of the WMNs) who are price- and quality-of-service (QoS)- sensitive, respond to AP providers’ pricing policies by controlling their usage. This research exploits the efficiency of dynamic pricing by integrating pricing into best effort based WMNs as an economic control tool to optimize the profit of the AP providers and improve the utilization of their limited uplink bandwidth by taking into consideration the resale-users’ price- and QoS- sensitivity. Two cases are presented in this thesis: a monopoly, where a single AP provider aims to maximize its profit while guaranteeing its resale-users with a minimum allocated bandwidth; and a duopoly, where two AP providers compete to maximize their individual profits based on the resale-users’ price- and delay- sensitivity. For both cases, the limited uplink bandwidth of the AP providers is considered as a bottleneck of the WMN. We propose two dynamic pricing models for these two cases respectively and investigate how pricing depends on the assumptions that we make about the market. Indeed, the pricing model proposed for the monopoly is a preliminary study for the duopoly pricing model. In formulating and analyzing these two pricing models, we see how prices are driven by the profit-maximizing aim of one AP provider and the competition between two AP providers.
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