Research On Invulnerability And Reliability-oriented Routing Algorithm For Highway Freight Network Under Time-sequenced Failure

Event-led failure risks have led to costly spikes in the supply chain,particularly in the highway freight segment,an issue that has led to extensive discussion and reflection on resilience research in highway freight systems.While many studies have been conducted to discuss the resilience of highway freight systems to cope with risk,research based on real-world data targeting the potential resilience and route reliability enhancement of multiple highway class coupled highway freight network(Highway Freight Network,HFN)under the risk of event-led failures is still limited.Therefore,the main research of this thesis is to define eventled failures with a temporal dimension,represented by city lockdown,as time-sequenced failure,to construct a framework for HFN time-sequenced failure analysis according to the scientific problem research idea,and to conduct invulnerability modelling and reliable route algorithm design based on the construction of the HFN and its extended super-network(Highway Freight Super-Network,HFSN),which will provide a systematic evaluation and solution framework for HFN under time-sequenced failure.Specific studies include:(1)From the technical path,a node invulnerability-based cascading failure invulnerability evaluation model is constructed,and a reliability-oriented route generation algorithm is designed.In this thesis,a cascading failure simulation model is constructed considering the invulnerability parameters of the failed nodes,and an integrated metric of network distance,network efficiency and network cargo flow strength is proposed to evaluate the network invulnerability,and the impact of timing faults on the HFN invulnerability is investigated.Following this,a heuristic algorithm to cope with the disturbance of the time-sequenced failure is designed based on HFSN: the reliability-oriented route generation algorithm(ReliabilityOriented Routing Algorithm,RORA).A bidirectional rollback search with the improved k-shell(Improved K-Shell,IKS)value of the node and the rollback value metric as reliability constraints can better exploit the role of the transport influence of the network elements.A system of algorithm assessment metrics is also proposed: efficiency,accuracy(average impedance ratio)and route reliability(alternative route multiplicity and generalized transport cost increment).(2)From the experimental analysis,HFN invulnerability analysis(failure attack mechanism,failure propagation mechanism and failure node heterogeneity perspective)with RORA for route generation experiments and route reliability sensitivity analysis.The simulation results of the failure attack mechanism show that the convergence time of cascading failures under the time-sequenced failure attack mechanism is only 5% of that under full failure and does not collapse,which implies that the HFN has greater invulnerability to destruction under the time-sequenced failure attack mechanism.The analysis of the fault propagation mechanism also shows that the HFN is more resistant to destruction after the peak of the timesequenced failure compared to the previous period.Moreover,large prefectures with high importance and high transport capacity(79%)are resistant to time-sequenced failure,the failure of such nodes can still have a significant impact on the overall invulnerability of the HFN.Furthermore,compared to the shortest-circuit algorithm,RORA results in a 16% increase in the network’s threshold value for withstanding failures and an approximate 60.58% reduction in the incremental generalized transport cost of the solution,meaning that RORA yields a more reliable route solution.The route reliability analysis also shows that the IKS value of the node is positively correlated with route reliability.Different highway classes may have different route reliability(highest for highways,uneven for national highways and lowest for provincial highways).In overview,this thesis validates the feasibility and superiority of the HFN time-sequenced failure analysis framework,which is dominated by destructive modelling and reliable route algorithms,for application to general problems.Analysis results also provide insights on perspectives focusing on failure types,spatial and temporal variability of failures,and locations and categories of key elements of the network.These findings can provide decision support to transport decision makers on strategies for freight system invulnerability enhancement and reliable route performance improvement under time-sequenced failures.