An Alias Resolution Method Based on Delay Sequence Analysis

Alias resolution,mapping IP addresses to routers,is a critical step in obtaining a network topology.The latest work on alias resolution is based on special fields in the packet,such as IP ID,port number,etc.However,for security reasons,most network devices block packets for setting options,and some related fields exist only in IPv4,so these methods cannot be used for alias resolution of IPv6.In order to solve the above problems,we propose an alias analysis method based on delay sequence analysis.In this article,we present a new model to describe the distribution of Internet delays and give a mathematical proof.After experimental measurements using the Macroscopic Internet Topology Data Kit(ITDK)and Ark IPv6 Topology Dataset,it was found that the statistical differences in most alias delay models were very small.The statistical differences in the non-alias delay models are spread over a wide range.Using the wavelet decomposition in delay sequence,it was found that the approximate components and the detail components of the delay sequence of aliases were the same after filtering out the noise,which provided a theoretical explanation for the experimental results.This technology is applicable to both IPv4 and IPv6.

Sources,characteristics,toxicity,and control of ultrafine particles:An overview

Air pollution by particulate matter(PM)is one of the main threats to human health,particularly in large cities where pollution levels are continually exceeded.According to their source of emission,geography,and local meteorology,the pollutant particles vary in size and composition.These particles are conditioned to the aerodynamic diameter and thus classified as coarse(2.5–10μm),fine(0.1–2.5μm),and ultrafine(<0.1μm),where the degree of toxicity becomes greater for smaller particles.These particles can get into the lungs and translocate into vital organs due to their size,causing significant human health consequences.Besides,PM pollutants have been linked to respiratory conditions,genotoxic,mutagenic,and carcinogenic activity in human beings.This paper presents an overview of emission sources,physicochemical characteristics,collection and measurement methodologies,toxicity,and existing control mechanisms for ultrafine particles(UFPs)in the last fifteen years.