This paper aims at presenting a detailed analysis of the impact of multiple natural disasters on local populations using mobile phone data. The analysis performed demonstrates that accurate measurements of population displacements could be available in almost real-time. Moreover, data-driven information can be extracted to compare the recovery process in different areas. The coverage and precision of mobile phone data is typically better than what is available from social media, and also provides information about infrastructure damage when cell towers go offline. This paper aims at paving the way to make aggregate measurements of population movements available to officials responsible for evacuation orders and first responders, in order to improve disaster management and recovery processes.

BCH codes are an interesting type of cyclic codes and have wide applications in communication and storage systems. Generally, it is very hard to determine the minimum distances of BCH codes. In this paper, we determine the weight distributions of two classes of primitive BCH codes C(q,m,δ(2))and C(q,m,δ(3))and their extended codes, which solve two problems proposed by Ding et al. It is shown that the extended codes C̅(q,m,δ(2))have four nonzero weights. We also employ the Hartmann-Tzeng bound to present the minimum distance of the dual code C⊥(q,m,δ(2))for q ≥ 5. Inspired by the idea, we then determine the dimensions of a class of cyclic codes and give lower bounds on their minimum distances, which is greatly improved comparing with the BCH bound. Some optimal codes are obtained.

This paper aims at presenting a detailed analysis of the impact of Hurricane Harvey on residents in South Texas using mobile phone data. The analysis performed demonstrates that accurate measurements of population displacements could be available in almost real-time. Moreover, data-driven information can be extracted to compare the recovery process in different areas. The coverage and precision of mobile phone data is typically better than what is available from social media, and also provides information about infrastructure damage when cell towers go offline. This paper aims at paving the way to make aggregate measurements of population movements available to officials responsible for evacuation orders and first responders, in order to improve disaster management and recovery processes.

Several new results on the nonexistence of generalized bent functions are proved by using properties of the decomposition law of primes and the class group of imaginary Abelian number fields.