Grey relation projection model for the assessment of permafrost environment in coal mining areas

Due to the intense effect of coal mining activity on permafrost,the permafrost environment in coal mining areas is very frail.It is very important to assess the permafrost environment in coal mining areas.The permafrost environment is a grey system.A grey relation projection model for permafrost environment assessment in coal mining areas is established based on the grey system theory and vector projection principle.In the model,evaluated samples and classified standards are treated as vectors,w...