Heterogeneous Strong Computation Migration

The continuous increase in performance requirements, for both scientific computation and industry, motivates the need of a powerful computing infrastructure. The Grid appeared as a solution for inexpensive execution of heavy applications in a parallel and distributed manner. It allows combining resources independently of their physical location and architecture to form a global resource pool available to all grid users. However, grid environments are highly unstable and unpredictable. Adaptability is a crucial issue in this context, in order to guarantee an appropriate quality of service to users. Migration is a technique frequently used for achieving adaptation. The objective of this report is to survey the problem of strong migration in heterogeneous environments like the grids', the related implementation issues and the current solutions.Comment: This is the pre-peer reviewed version of the following article: Milan\'es, A., Rodriguez, N. and Schulze, B. (2008), State of the art in heterogeneous strong migration of computations. Concurrency and Computation: Practice and Experience, 20: 1485-1508, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/cpe.1287/abstrac

On the interplay of speciation and dispersal: An evolutionary food web model in space

We introduce an evolutionary metacommunity of multitrophic food webs on several habitats coupled by migration. In contrast to previous studies that focus either on evolutionary or on spatial aspects, we include both and investigate the interplay between them. Locally, the species emerge, interact and go extinct according to the rules of the well-known evolutionary food web model proposed by Loeuille and Loreau in 2005. Additionally, species are able to migrate between the habitats. With random migration, we are able to reproduce common trends in diversity-dispersal relationships: Regional diversity decreases with increasing migration rates, whereas local diversity can increase in case of a low level of dispersal. Moreover, we find that the total biomasses in the different patches become similar even when species composition remains different. With adaptive migration, we observe species compositions that differ considerably between patches and contain species that are descendant from ancestors on both patches. This result indicates that the combination of spatial aspects and evolutionary processes affects the structure of food webs in different ways than each of them alone.Comment: under review at JT

Prototyping the recursive internet architecture: the IRATI project approach

In recent years, many new Internet architectures are being proposed to solve shortcomings in the current Internet. A lot of these new architectures merely extend the current TCP/IP architecture and hence do not solve the fundamental cause of these problems. The Recursive Internet Architecture (RINA) is a true new network architecture, developed from scratch, building on lessons learned in the past. RINA prototyping efforts have been ongoing since 2010, but a prototype on which a commercial RINA implementation can be built has not been developed yet. The goal of the IRATI research project is to develop and evaluate such a prototype in Linux/OS. This article focuses on the software design required to implement a network stack in Linux/OS. We motivate the placement of, and communication between, the different software components in either the kernel or user space. The first open source prototype of the IRATI implementation of RINA will be available in June 2014 for researchers, developers, and early adopters

Immigration and innovation in European regions

The pooling of people with diverse backgrounds in particular areas may boost the creation of new ideas, knowledge spillovers, entrepreneurship and economic growth. In this paper we measure the impact of the size, skills and diversity of immigration on innovativeness of host regions. For this purpose we construct a panel of data on 170 regions in Europe (NUTS 2 level) for the period 1991-2001. Innovation outcomes are measured by means of the number and types of patent applications. Given the geographical concentration and subsequent diffusion of innovation activity, and the spatial selectivity of immigrant settlement patterns, we take account of spatial dependence and of endogeneity of immigrant settlement in the econometric modelling. We find that an increase in patent applications in a region is associated with (i) net immigration; (ii) the share of foreigners in the population of the region; (iii) the average skill level of the immigrants; and (iv) the cultural diversity of the immigrants. The magnitude of these effects varies between types of patents

Chicano and african-american autobiographies : identities on the border

La comunidad chicana y la afro-americana muestran una identidad claramente heterogénea debido a su tradición migratoria. En el caso de los chicanos, su situación geográfica les proporciona una metáfora muy adecuada para su condición: se encuentran en una "frontera cultural". Así, muchas autobiografías de autores chicanos muestran, por una parte, un afán por definir la propia identidad, no ya como algo rígido sino como una realidad dinámica. Por otra, se aprecia la creación de un lenguaje particular mediante la incorporación al discurso dominante de formas de expresión propias. Por su parte, la comunidad afro-americana presenta algunos intentos de naturaleza similar. Esto indica que sus escritores avanzan en la dirección adecuada hacia una "escritura de frontera"

Chicano and african-american autobiographies : identities on the border

La comunidad chicana y la afro-americana muestran una identidad claramente heterogénea debido a su tradición migratoria. En el caso de los chicanos, su situación geográfica les proporciona una metáfora muy adecuada para su condición: se encuentran en una "frontera cultural". Así, muchas autobiografías de autores chicanos muestran, por una parte, un afán por definir la propia identidad, no ya como algo rígido sino como una realidad dinámica. Por otra, se aprecia la creación de un lenguaje particular mediante la incorporación al discurso dominante de formas de expresión propias. Por su parte, la comunidad afro-americana presenta algunos intentos de naturaleza similar. Esto indica que sus escritores avanzan en la dirección adecuada hacia una "escritura de frontera"

The Economic Impact of Immigrant-Related Local Ordinances

Compares business environments of cities with restrictive policies such as requiring verification of employees' and tenants' immigration status or giving local officials immigration enforcement powers and those of cities with non-restrictive policies

Mobile computing in a clouded environment

textCloud Computing has started to become a viable option for computing centers and mobile consumers seeking to reduce cost overhead, power consumption, and increase software services available within their platform. For instance distributed memory constrained mobile devices can expand their ability to share real time data by utilizing virtual memory located within the cloud. Cloud memory services can be configured to restrict read and write access to the shared memory pool on a partner by partner basis. Utilization of such resources in turn reduces hardware requirements on mobile devices while lessening power consumption for each physical resource. Within the Cloud Computing paradigm, computing resources are provisioned to consumers on demand and guaranteed through service level agreements. Although the idea of a computing utility is not new, its realization has come to pass as researchers and corporate companies embark on a journey of implementing highly scalable cloud environments. As new solutions and architectures are proposed, additional use cases and consumer concerns have been revealed. These issues range from consumer security, adequate service level agreements and vendor interoperability, to cloud technology standardizations. Further, the current state of the art does not adequately address these needs for mobile consumers, where services need to be guaranteed even as consumers dynamically change locations. Due to the rapid adoption of virtualization stacks and the dramatic increase of mobile computing devices, cloud providers must be able to handle logical and physical mobility of consumers. As consumers move throughout geographical regions, there exists the probability that a consumer’s new locale may hinder a producer’s ability to uphold service level agreements. This inability is due to the fact that a producer may not have physical resources located relatively close to a mobile consumer’s new locale. As a consequence, producers must either continue to provide degraded resource consumption or migrate workloads to third party producers in order to ensure service level agreements are maintained. The goal of this report is to research existing architectures that provide the ability to adequately uphold service level agreements as mobile consumers move from locale to locale. Further we propose an architecture that can be implemented along with existing solutions in order to ensure consumers receive adequate service levels regardless of locality. We believe this architecture will lead to increased cloud interoperability and decreased consumer to producer platform coupling.Electrical and Computer Engineerin