Validating the Runoff from the PRECIS Model Using a Large-Scale Routing Model

The streamflow over the Yellow River basin is simulated using the PRECIS （Providing REgional Climates for Impacts Studies） regional climate model driven by 15-year （1979-1993） ECMWF reanalysis data as the initial and lateral boundary conditions and an off-line large-scale routing model （LRM）. The LRM uses physical catchment and river channel information and allows streamflow to be predicted for large continental rivers with a 1°×1° spatial resolution. The results show that the PRECIS model can reproduce the general southeast to northwest gradient distribution of the precipitation over the Yellow River basin, The PRECIS- LRM model combination has the capability to simulate the seasonal and annual streamflow over the Yellow River basin. The simulated streamflow is generally coincident with the naturalized streamflow both in timing and in magnitude.

Research on Data Routing Model Based on Ant Colony Algorithms

Improved traditional ant colony algorithms,a data routing model used to the data remote exchange on WAN was presented.In the model,random heuristic factors were introduced to realize multi-path search.The updating model of pheromone could adjust the pheromone concentration on the optimal path according to path load dynamically to make the system keep load balance.The simulation results show that the improved model has a higher performance on convergence and load balance.

Application of Muskingum routing method with variable parameters in ungauged basin

This paper describes a flood routing method applied in an ungauged basin, utilizing the Muskingum model with variable parameters of wave travel time K and weight coefficient of discharge x based on the physical characteristics of the river reach and flood, including the reach slope, length, width, and flood discharge. Three formulas for estimating parameters of wide rectangular, triangular, and parabolic cross sections are proposed. The influence of the flood on channel flow routing parameters is taken into account. The HEC-HMS hydrological model and the geospatial hydrologic analysis module HEC-GeoHMS were used to extract channel or watershed characteristics and to divide sub-basins. In addition, the initial and constant-rate method, user synthetic unit hydrograph method, and exponential recession method were used to estimate runoff volumes, the direct runoff hydrograph, and the baseflow hydrograph, respectively. The Muskingum model with variable parameters was then applied in the Louzigou Basin in Henan Province of China, and of the results, the percentages of flood events with a relative error of peak discharge less than 20% and runoff volume less than 10% are both 100%. They also show that the percentages of flood events with coefficients of determination greater than 0.8 are 83.33%, 91.67%, and 87.5%, respectively, for rectangular, triangular, and parabolic cross sections in 24 flood events. Therefore, this method is applicable to ungauged basins.

A framework of numerical simulation on moraine-dammed glacial lake outburst floods

Glacial outburst floods（GLOFs） in alpine regions tend to be relatively complicated, multi-stage catastrophes, capable of causing significant geomorphologic changes in channel surroundings and posing severe threats to infrastructure and the safety and livelihoods of human communities. GLOF disasters have been observed and potential hazards can be foreseen due to the newly formed glacial lakes or the expansion of existing ones in the Poiqu River Basin in Tibet, China. Here we presented a synthesis of GLOF-related studies including triggering mechanism（s）, dam breach modeling, and flood routing simulation that have been employed to reconstruct or forecast GLOF hydrographs. We provided a framework for probability-based GLOFs simulation and hazard mapping in the Poiqu River Basin according to available knowledge. We also discussed the uncertainties and challenges in the model chains, which may form the basis for further research.

Shape Co-Existence in the Transitional Nuclide ^(157)yb

High-spin states in 157Yb have been populated in the 144Sm（160, 3n）157yb fusion- evaporation reaction at a beam energy of 85 MeV, and two rotational bands have been established for the first time. Within the framework of the triaxial particle-rotor model, the energy spectra and single-particle configurations of 157Yb are investigated. The calculated energy spectra agree well with the experimental data. The newly observed vf7/2 band, and the previously known vi13/2 band in 157Yb, are also discussed by means of Total-Routhian-Surface methods. The structural characters observed in 157Yb provide evidence for the shape coexistence of three distinct shapes： prolate, triaxial and oblate. At higher spins, both the vf7/2 band and the vi13/2 band in 157Yb undergo a shape evolution with sizable alignments occurring.

MULTIOBJECTIVE ROUTING IN MULTISERVICE MPLS NETWORKS WITH TRAFFIC SPLITTING-A NETWORK FLOW APPROACH

A multiobjective routing model for Multiprotocol Label Switching networks with multiple service types and traffic splitting is presented in this paper. The routing problem is formulated as a multiobjective mixed-integer program, where the considered objectives are the minimization of the bandwidth routing cost and the minimization of the load cost in the network links with a constraint on the maximal splitting of traffic trunks. Two different exact methods are developed for solving the formulated problem, one based on the classical constraint method and another based on a modified constraint method. A very extensive experimental study, with results on network performance measures in various reference test networks and in randomly generated networks, is also presented and its results are discussed.

Operational Risk-averse Routing Optimization for Cyber-physical Power Systems

The extensive application of modern information and communication technology in the power system through the in-depth integration of the information system and the power system has led to the gradual development of the cyberphysical power system(CPPS).While advanced information technology increases the safety and reliability of power system operations,it also increases the risks of fault propagation.To improve the reliability of CPPS from the perspective of power communication routing,it is proposed that the CPPS model and vulnerability assessment of power node reflect the correlation between information and energy flows with the service impact on power grid operation,which is an important index for evaluating communication services.According to the distribution of services at the different important levels on the links,the importance of the cross-layer link is established as the vulnerability evaluation index of the communication network.Then,the routing optimization model is proposed in combination with the service transmission risk under cyber-attack and the operating characteristics of the information system,which is solved through an improved fast-convergent genetic algorithm.The simulation results show that the proposed method allocates the alternate route to the low-risk link without significantly increasing the delay of the main route,which effectively improves the power supply reliability of CPPS in extreme cyber-attack scenarios.

Analysing taxi customer-search behaviour using Copula-based joint model

The drivers of vacant taxis tend to cruise the road network searching new passengers,which leads to additional traffic congestion,air pollution and other problems.This study introduces a Copula-based joint model to analyse destination selection and route choice behaviour in the customer-search process.A multinomial logit model is used to analyse the destination selection behaviour,and a path size logit model is used to explore the routes choice behaviour.Accordingly,the joint model applied Copula function is then established to analyse the correlation between these two behaviours.The destination customer generation rate,destination distance,route customer generation rate,path travel time,cumulative intersection delay,path size and route length are selected as explanatory variables.The taxis trajectory data were collected by global positioning system in Xidan District of Beijing City from September 2014 to February 2015.Using the log-likelihood,Bayesian information criterion as evaluation indexes to measure the fitting result,the joint model applied Copula function has the highest goodness-of-fit.The effect of explanatory variables on customer search behaviour is discussed based on the parameter estimation results.The results of this study are helpful to understand the customer-search behaviour of taxi drivers to reduce operating costs and improve the efficiency of the taxi operation system.

An integrated approach for dynamic traffic routing and ramp metering using sliding mode control

The problem of designing integrated traffic control strategies for highway networks with the use of route guidance, ramp metering is considered. The highway network is simulated using a first order macroscopic model called LWR model which is a mathematical traffic flow model that formulates the relationships among traffic flow characteristics in terms of density, flow, and mean speed of the traffic stream. An integrated control algorithm is designed to solve the proposed problem, based on the inverse control technique and variable structure control（super twisting sliding mode）. Three case studies have been tested in the presence of an on-ramp at each alternate route and where there is a capacity constraint in the network. In the first case study, there is no capacity constraint at either upstream or downstream of the alternate routes and the function of the proposed algorithm is only to balance the traffic flow on the alternate routes. In the second case study, there is capacity constraint at downstream of alternate routes. The proposed algorithm aims to avoid congestion on the main road and balance the traffic flow on the alternate routes. In the last case study, there is capacity constraint at upstream of alternate routes. The objective of proposed algorithm is to avoid congestion on the main road and to balance the traffic flow on the alternate routes. The obtained results show that the proposed algorithms can establish user equilibrium between two alternate routes even when the on-ramps, located at alternate routes, have different traffic demands.