With the rapid development of mobile wireless Internet and high-precision localization devices,location-based services(LBS)bring more convenience for people over recent years.In LBS,if the original location data are d...With the rapid development of mobile wireless Internet and high-precision localization devices,location-based services(LBS)bring more convenience for people over recent years.In LBS,if the original location data are directly provided,serious privacy problems raise.As a response to these problems,a large number of location-privacy protection mechanisms(LPPMs)(including formal LPPMs,FLPPMs,etc.)and their evaluation metrics have been proposed to prevent personal location information from being leakage and quantify privacy leakage.However,existing schemes independently consider FLPPMs and evaluation metrics,without synergizing them into a unifying framework.In this paper,a unified model is proposed to synergize FLPPMs and evaluation metrics.In detail,the probabilistic process calculus(calledδ-calculus)is proposed to characterize obfuscation schemes(which is a LPPM)and integrateα-entropy toδ-calculus to evaluate its privacy leakage.Further,we use two calculus moving and probabilistic choice to model nodes’mobility and compute its probability distribution of nodes’locations,and a renaming function to model privacy leakage.By formally defining the attacker’s ability and extending relative entropy,an evaluation algorithm is proposed to quantify the leakage of location privacy.Finally,a series of examples are designed to demonstrate the efficiency of our proposed approach.展开更多
Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resili...Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resilience of IDIMGs can be achieved by maxim-izing the system loadability and/or mitigating the expected disturbances such as line switching operations.This paper proposes a two-stage framework based on the deployment of mobile energy storage(MES)to enhance the resilience of IDIMGs.In the first stage,the network configuration and deployment of MES are optimized to maximize the system loadability.The proposed formulation for this stage is a stochastic multi-period mixed-integer nonlinear program(MINLP)that maximizes a weighted sum of minimax loadabilities.In the second stage,transitional locations of MES,line-exchange execution sequence,and droop control of dispatchable sources are jointly optimized to mitigate line-switching disturbances that occur when transitioning to the new network configuration obtained in the first stage.The second stage model is a multi-objective MINLP.The proposed models are solved within the gen-eral algebraic modeling system(GAMS),utilizing a mod-ified IEEE 33-bus system.Simulations are conducted to assess the significance of each proposed model,and the results reveal remarkable improvements in system loadability with the utilization of the first-stage model and significant reductions in the total switched power with the adoption of the second-stage model.展开更多
基金This research is supported in part by the National Key Research and Development Program of China(Grant No.2017YFB0803001)in part by the Key research and Development Program for Guangdong Province under grant(Grant No.2019B010136001)+1 种基金in part by the National Natural Science Foundation of China(Grant No.61872100)Guangxi Natural Science Foundation(No.2017GXNSFAA198372).
文摘With the rapid development of mobile wireless Internet and high-precision localization devices,location-based services(LBS)bring more convenience for people over recent years.In LBS,if the original location data are directly provided,serious privacy problems raise.As a response to these problems,a large number of location-privacy protection mechanisms(LPPMs)(including formal LPPMs,FLPPMs,etc.)and their evaluation metrics have been proposed to prevent personal location information from being leakage and quantify privacy leakage.However,existing schemes independently consider FLPPMs and evaluation metrics,without synergizing them into a unifying framework.In this paper,a unified model is proposed to synergize FLPPMs and evaluation metrics.In detail,the probabilistic process calculus(calledδ-calculus)is proposed to characterize obfuscation schemes(which is a LPPM)and integrateα-entropy toδ-calculus to evaluate its privacy leakage.Further,we use two calculus moving and probabilistic choice to model nodes’mobility and compute its probability distribution of nodes’locations,and a renaming function to model privacy leakage.By formally defining the attacker’s ability and extending relative entropy,an evaluation algorithm is proposed to quantify the leakage of location privacy.Finally,a series of examples are designed to demonstrate the efficiency of our proposed approach.
文摘Inverter-dominated isolated/islanded microgrids(IDIMGs)lack infinite buses and have low inertia,resulting in higher sensitivity to disturbances and reduced stability compared to grid-tied systems.Enhanc-ing the resilience of IDIMGs can be achieved by maxim-izing the system loadability and/or mitigating the expected disturbances such as line switching operations.This paper proposes a two-stage framework based on the deployment of mobile energy storage(MES)to enhance the resilience of IDIMGs.In the first stage,the network configuration and deployment of MES are optimized to maximize the system loadability.The proposed formulation for this stage is a stochastic multi-period mixed-integer nonlinear program(MINLP)that maximizes a weighted sum of minimax loadabilities.In the second stage,transitional locations of MES,line-exchange execution sequence,and droop control of dispatchable sources are jointly optimized to mitigate line-switching disturbances that occur when transitioning to the new network configuration obtained in the first stage.The second stage model is a multi-objective MINLP.The proposed models are solved within the gen-eral algebraic modeling system(GAMS),utilizing a mod-ified IEEE 33-bus system.Simulations are conducted to assess the significance of each proposed model,and the results reveal remarkable improvements in system loadability with the utilization of the first-stage model and significant reductions in the total switched power with the adoption of the second-stage model.
