This paper studies how to obtain a reasonable traveling route among given attractions. Toward this purpose, we propose an objective optimization model of routes choosing, which is based on the improved Ant Colony Algo...This paper studies how to obtain a reasonable traveling route among given attractions. Toward this purpose, we propose an objective optimization model of routes choosing, which is based on the improved Ant Colony Algorithm. Furthermore, we make some adjustment in parameters in order to improve the precision of this algorithm. For example, the inspired factor has been changed to get better results. Also, the ways of searching have been adjusted so that the traveling routes will be well designed to achieve optimal effects. At last, we select a series of attractions in Beijing as data to do an experimental analysis, which comes out with an optimum route arrangement for the travelers;that is to say, the models we propose and the algorithm we improved are reasonable and effective.展开更多
This paper develops a new class of multivariate models for large-dimensional time-varying covariance matrices,called Cholesky generalized autoregressive score(GAS)models,which are based on the Cholesky decomposition o...This paper develops a new class of multivariate models for large-dimensional time-varying covariance matrices,called Cholesky generalized autoregressive score(GAS)models,which are based on the Cholesky decomposition of the covariance matrix and assume that the parameters are score-driven.Specifically,two types of score-driven updates are considered:one is closer to the GARCH family,and the other is inspired by the stochastic volatility model.We demonstrate that the models can be estimated equation-wise and are computationally feasible for high-dimensional cases.Moreover,we design an equationwise dynamic model averaging or selection algorithm which simultaneously extracts model and parameter uncertainties,equipped with dynamically estimated model parameters.The simulation results illustrate the superiority of the proposed models.Finally,using a sizeable daily return dataset that includes 124 sectors in the Chinese stock market,two empirical studies with a small sample and a full sample are conducted to verify the advantages of our models.The full sample analysis by a dynamic correlation network documents significant structural changes in the Chinese stock market before and after COVID-19.展开更多
文摘This paper studies how to obtain a reasonable traveling route among given attractions. Toward this purpose, we propose an objective optimization model of routes choosing, which is based on the improved Ant Colony Algorithm. Furthermore, we make some adjustment in parameters in order to improve the precision of this algorithm. For example, the inspired factor has been changed to get better results. Also, the ways of searching have been adjusted so that the traveling routes will be well designed to achieve optimal effects. At last, we select a series of attractions in Beijing as data to do an experimental analysis, which comes out with an optimum route arrangement for the travelers;that is to say, the models we propose and the algorithm we improved are reasonable and effective.
基金The authors would like to acknowledge that this work is supported by the Basic Scientific Center of National Science Foundation of China(Project 71988101)the Humanities and Social Science Fund of Ministry of Education of the People's Republic of China under Grant No.22JJD790050+4 种基金the National Natural Science Foundation of China,General Program under Grant No.71973110 and No.72373125the National Natural Science Foundation of China,Key Program under Grant No.72033008the Fundamental Research Funds for the Central Universities under Grant No.20720191072the Statistical Science Research Program of China under Grant No.2022LZ37 and No.2022LZ06the Cultivation Program of Financial Security Collaborative Innovation Center,Southwestern University of Finance and Economics under Grant No.JRXTP202202.
文摘This paper develops a new class of multivariate models for large-dimensional time-varying covariance matrices,called Cholesky generalized autoregressive score(GAS)models,which are based on the Cholesky decomposition of the covariance matrix and assume that the parameters are score-driven.Specifically,two types of score-driven updates are considered:one is closer to the GARCH family,and the other is inspired by the stochastic volatility model.We demonstrate that the models can be estimated equation-wise and are computationally feasible for high-dimensional cases.Moreover,we design an equationwise dynamic model averaging or selection algorithm which simultaneously extracts model and parameter uncertainties,equipped with dynamically estimated model parameters.The simulation results illustrate the superiority of the proposed models.Finally,using a sizeable daily return dataset that includes 124 sectors in the Chinese stock market,two empirical studies with a small sample and a full sample are conducted to verify the advantages of our models.The full sample analysis by a dynamic correlation network documents significant structural changes in the Chinese stock market before and after COVID-19.
