Parabolic reaction-diffusion systems with nonlocal coupled diffusivity terms

In this work we study a system of parabolic reaction-diffusion equations which are coupled not only through the reaction terms but also by way of nonlocal diffusivity functions. For the associated initial problem, endowed with homogeneous Dirichlet or Neumann boundary conditions, we prove the existence of global solutions. We also prove the existence of local solutions but with less assumptions on the boundedness of the nonlocal terms. The uniqueness result is established next and then we find the conditions under which the existence of strong solutions is assured. We establish several bow-up results for the strong solutions to our problem and we give a criterium for the convergence of these solutions towards a homogeneous state.CAPES [BEX 2478-12-8]; MEC/MCTI/CAPES/CNPq/FAPs, Brazil [71/2013, 88881.030388/2013-01]; Fundacao para a Ciencia e a Tecnologia, Portugal [UID/MAT/04561/2013-2015]info:eu-repo/semantics/publishedVersio

On the Use of Suffix Arrays for Memory-Efficient Lempel-Ziv Data Compression

Much research has been devoted to optimizing algorithms of the Lempel-Ziv (LZ) 77 family, both in terms of speed and memory requirements. Binary search trees and suffix trees (ST) are data structures that have been often used for this purpose, as they allow fast searches at the expense of memory usage. In recent years, there has been interest on suffix arrays (SA), due to their simplicity and low memory requirements. One key issue is that an SA can solve the sub-string problem almost as efficiently as an ST, using less memory. This paper proposes two new SA-based algorithms for LZ encoding, which require no modifications on the decoder side. Experimental results on standard benchmarks show that our algorithms, though not faster, use 3 to 5 times less memory than the ST counterparts. Another important feature of our SA-based algorithms is that the amount of memory is independent of the text to search, thus the memory that has to be allocated can be defined a priori. These features of low and predictable memory requirements are of the utmost importance in several scenarios, such as embedded systems, where memory is at a premium and speed is not critical. Finally, we point out that the new algorithms are general, in the sense that they are adequate for applications other than LZ compression, such as text retrieval and forward/backward sub-string search.Comment: 10 pages, submited to IEEE - Data Compression Conference 200

Business Model Generation: A handbook for visionaries, game changers and challengers

The book entitled “Business Model Generation: A Handbook for visionaries, game changers and challengers” though written by Osterwalder and Pigneur (2010) was also co-created by 470 practitioners from 45 countries. The book is thus a good example of how a global creative collaboration effort can contribute positively to the business and management literature and subsequently to the advancement of society. The book "Business Model Generation" has both narrative and visual detail. Before proceeding to do an in-depth review of “Business Model Generation” we first looked at other publications by the authors which led up to the book

Producing innovation: Comments on Lee and Yu (2010)

The purpose of the article being reviewed (Lee and Yu, 2010), a survey by questionnaire with 182 valid responses, is to analyze “how different relationship styles of employees in the hi-tech industry influence innovation performance” and indeed its conclusions are that “the relationship style of an organization has a significant positive effect on innovation performance”. We see Lee and Yu (2010) as being similar to another highly cited article by Morgan and Hunt in so far as both articles are about relationships, cooperation and trust

Hans Kelsen and the tradition of natural law: why Kelsen’s objections to the natural-law doctrine does not apply against Aquinas’s theory of natural law

In his works, Hans Kelsen elaborates several objections to the so-called “doctrine of natural law”, especially in his essay The Natural-Law Doctrine Before the Tribunal of Science. Kelsen argues that natural law theorists, searching for an absolute criterion for justice, try to deduce from nature the rules of human behavior. Robert P. George, in the essay Kelsen and Aquinas on the ‘Natural Law Doctrine’ examines his criticism and concludes that what Kelsen understands as the Natural-law doctrine does not include the natural law theory elaborated by Thomas Aquinas. In this paper, we will try to corroborate George’s theses and try to show how Aquinas’ natural law theory can be vindicated against Kelsens criticisms