Conformally covariant quantization of Maxwell field in de Sitter space

In this article, we quantize the Maxwell ("massless spin one") de Sitter field in a conformally invariant gauge. This quantization is invariant under the SO$_0(2,4)$ group and consequently under the de Sitter group. We obtain a new de Sitter invariant two-points function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in \setR^6 and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.Comment: v2 is is the definitive (improved compare to v1) versio

La construcción de la memoria escrita en los archivos eclesiásticos de Ribagorza (ss. XI-XIII)

During the eleventh century, the main ecclesiastical institutions in Ribagorza and surrounding areas underwent a deep transformation and growth, through the intervention of monarchs and bishops. Starting then and up to 1150, the earlier archival materials were selected, compiled and modified; indeed, few documents survived that had not been made part of the resulting documentary products which will be analysed in this article. Within that context, there was a constant dialogue between the churchmen’s present and their immediate and distant past, which led to the construction of a coherent narrative of their history, intended to legitimize their present and secure their own interests.Durante el siglo XI las grandes instituciones eclesiásticas de Ribagorza y las comarcas colindantes atravesaron una profunda transformación y crecimiento debidos a la intervención monárquica y episcopal. Entre ese momento y 1150 se seleccionaron, compilaron y transformaron los materiales archivísticos anteriores, de modo que casi no sobrevivieron más escrituras altomedievales que las que se integraron en alguno de los productos documentales que se describen en este artículo. En ese contexto, se produjo un constante diálogo entre el presente de los religiosos, el pasado inmediato y el pasado remoto, que causó la construcción de una narración coherente de su historia, que tenía como objetivo justificar el presente y proteger sus intereses

Norm-based and commitment-driven agentification of the Internet of Things

There are no doubts that the Internet-of-Things (IoT) has conquered the ICT industry to the extent that many governments and organizations are already rolling out many anywhere,anytime online services that IoT sustains. However, like any emerging and disruptive technology, multiple obstacles are slowing down IoT practical adoption including the passive nature and privacy invasion of things. This paper examines how to empower things with necessary capabilities that would make them proactive and responsive. This means things can, for instance reach out to collaborative peers, (un)form dynamic communities when necessary, avoid malicious peers, and be “questioned” for their actions. To achieve such empowerment, this paper presents an approach for agentifying things using norms along with commitments that operationalize these norms. Both norms and commitments are specialized into social (i.e., application independent) and business (i.e., application dependent), respectively. Being proactive, things could violate commitments at run-time, which needs to be detected through monitoring. In this paper, thing agentification is illustrated with a case study about missing children and demonstrated with a testbed that uses different IoT-related technologies such as Eclipse Mosquitto broker and Message Queuing Telemetry Transport protocol. Some experiments conducted upon this testbed are also discussed

Cognitive computing meets the internet of things

Abstract: This paper discusses the blend of cognitive computing with the Internet-of-Things that should result into developing cognitive things. Today’s things are confined into a data-supplier role, which deprives them from being the technology of choice for smart applications development. Cognitive computing is about reasoning, learning, explaining, acting, etc. In this paper, cognitive things’ features include functional and non-functional restrictions along with a 3 stage operation cycle that takes into account these restrictions during reasoning, adaptation, and learning. Some implementation details about cognitive things are included in this paper based on a water pipe case-study

Which social networks should web services sign-up in?

This paper deals with the sign up issue in social networks populated with Web services. These social networks can be used for example, to ease the discovery of Web services. Based on Web services\u27 functionalities three social networks are built: competition, substitution, and collaboration. In competition and substitution social networks, Web services offer homogeneous functionalities. In the collaboration social network, Web services that offer heterogeneous functionalities. In this latter type, Web services can be put together to develop composite services. Prior to joining a social network, a Web service through a third-party, named social Web service, should evaluate the pros and cons of being member in this network. A set of quality criteria for assessing these pros and cons are proposed. These criteria are, but not limited to, privacy, trust, fairness, and traceability. Policies for managing the sign up are, also, provided in this paper. The adoption and efficiency of these policies are monitored and assessed with respect to me values that these criteria take. In response to this sign up\u27s outcomes, these policies are fine-tuned. Copyright © 2012, Association for the Advancement of Artificial Intelligence. All rights reserved