Weighted average consensus problem in networks of agents with diverse time-delays

This paper studies the weighted average consensus problem for networks of agents with fixed directed asymmetric unbalance information exchange topology. We suppose that the classical distributed consensus protocol is destroyed by diverse time-delays which include communication time-delay and self time-delay. Based on the generalized Nyquist stability criterion and the Gerschgorin disk theorem, some sufficient conditions for the consensus of multi-agent systems are obtained. And we give the expression of the weighted average consensus value for our consensus protocol. Finally, numerical examples are presented to illustrate the theoretical results.

Improved HVSR site classification method for free-field strong motion stations validated with Wenchuan aftershock recordings

Local site conditions play an important role in the effective application of strong motion recordings.In the China National Strong Motion Observation Network System（NSMONS）,some of the stations do not provide borehole information,and correspondingly,do not assign the site classes yet.In this paper,site classification methodologies for free-field strong motion stations are reviewed and the limitations and uncertainties of the horizontal-to-vertical spectral ratio（HVSR） methods are discussed.Then,a new method for site classification based on the entropy weight theory is proposed.The proposed method avoids the head or tail joggle phenomenon by providing the objective and subjective weights.The method was applied to aftershock recordings from the 2008 Wenchuan earthquake,and 54 free-field NSMONS stations were selected for site classification and the mean HVSRs were calculated.The results show that the improved HVSR method proposed in this paper has a higher success rate and could be adopted in NSMONS.

SCC-UEFAS, an urban-ecological-feature based assessment system for sponge city construction

An effective sponge city construction evaluation system plays a crucial role in evaluating sponge city construction schemes.The construction of a sponge city evaluation system still faces challenges related to incomplete index selection and unscientific weight division.Limited studies have focused on the comprehensive assessment of sponge city construction in the early stages.This study constructed a scientific assessment indicator system and a quantitative indicator weight at all levels by literature review and statistical analysis methods from an objective perspective.To demonstrate how to utilize our evaluation methods,three construction schemes randomly generated by MATLAB were evaluated under evaluation states of constant weight and variable weight,respectively.Scheme 3 had the highest score of 0.638 under the constant weight assessment,but it cannot practically be the final construction scheme due to the imbalance between indicators.Compared to the constant weight assessment,a variable weight assessment can effectively balance the states of the evaluation index with changes in the decision variable.Among the three schemes,Scheme 2 is the best choice with a value of 0.0355 under variable weight evaluation due to punishment and incentives in the variable weight method.The concept of“punishing”a disadvantageous indicator and“motivating”an advantageous indicator increases the relative advantages of the indices,ultimately affecting the assessment results of schemes and leading to a more balanced state.This study provides reasonable analysis and decision-making mechanisms to support decision-making and guide the scientific selection of a construction scheme.

Detection Method for Cascading Failure of Power Systems Based on Epidemic Model

The early detection of cascading failure plays an important role in the safe and stable operation of the power system with high penetration of renewable energy.This paper proposes a fault propagation dynamic model based on the epidemic model,and further puts forward a method to detect the development of cascading failures.Through the simulation of the IEEE 39-bus and 118-bus systems,this model is proven to be valid and capable of providing practical technical support for the prevention of cascading failures in power systems with high penetration of renewable energy.This paper also provides an analysis method for the choice of different protection and control measures at each stage of cascading failure,which has critical significance and follow-up value.