Rich-club vs rich-multipolarization phenomena in weighted networks

Large scale hierarchies characterize complex networks in different domains. Elements at their top, usually the most central or influential, may show multipolarization or tend to club forming tightly interconnected communities. The rich-club phenomenon quantified this tendency based on unweighted network representations. Here, we define this metric for weighted networks and discuss the appropriate normalization which preserves nodes' strengths and discounts structural strength-strength correlations if present. We find that in some real networks the results given by the weighted rich-club coefficient can be in sharp contrast to the ones in the unweighted approach. We also discuss that the scanning of the weighted subgraphs formed by the high-strength hubs is able to unveil features contrary to the average: the formation of local alliances in rich-multipolarized environments, or a lack of cohesion even in the presence of rich-club ordering. Beyond structure, this analysis matters for understanding correctly functionalities and dynamical processes relying on hub interconnectedness.Comment: 12 pages, 2 figure

Weighted Configuration Model

The configuration model is one of the most successful models for generating uncorrelated random networks. We analyze its behavior when the expected degree sequence follows a power law with exponent smaller than two. In this situation, the resulting network can be viewed as a weighted network with non trivial correlations between strength and degree. Our results are tested against large scale numerical simulations, finding excellent agreement.Comment: Proceedings CNET200

Training senior employees for ICT skills enhancement through “refocus”: The EUROPEAN project

Declining fertility rates and the ageing of the European population represents a major challenge to many governments within the European Union (EU) and its neighbouring realms, in the present and for the forthcoming decades. The increasing ageing workforce within several United Kingdom (UK) and the EU private and public organisations is an evident manisfestation. The workforce comprised of senior employees are often seen by employers as less mobile and flexible with low performance and thus, less able to deal with the rapid changes occurring in their organisations; as rapid developments require flexible and responsive workforce. The mobility of the senior employees is therefore a topical theme in the workforce market. The necessary knowledge and skills required for the senior employees can be taught through various Information and Communication Technologies (ICT) related training systems within an organisation. However, it appears that the development of training systems required for senior employees need careful investigation into the requirements of the problem situation. The reason is that the design of senior employees training systems should be more carefully planned, as literature indicates that it is significantly time consuming and is harder to train senior employees on ICT applications. This paper presents a European project – REFOCUS (oldeR Employees training on inFOrmation and CommUnication technologieS), an initaitive undertaken by the EU for enhancing the ICT skills of the ageing workforce. This project also aims at designing a new electronic learning (e-Learning) method that focuses on the needs of senior employees of 40 years of age and over – who can become a strategic resource for the European economy

Modelling the integration of BP and IT using business process simulation

Information Technology (IT) and Business Process (BP) communities argues that the use of IT to support business processes can bring a number of benefits to the organisation. Most of these benefits, however, can only be seen after the implementation of such technology. Moreover, there are many cases where the benefits brought by the implementation of IT do not fulfil the organisation’s expectations. One reason of this may happen is because research in BP and IS domains show little indication of which modelling methods, techniques or tools can help organisations to foresee the benefits of the integration of IT with BP. This paper describes the insights gained during a UK funded research project, namely ASSESS-IT, which used simulation techniques to address this problem. Considering IT as a two layered system, namely Information Systems (IS) and Computer Networks (CN), ASSESS-IT aimed to depict the benefits that new IT may bring to the BP. This paper uses the outcomes derived from ASSESS-IT to suggest that, in some cases; the relationship between BP and IT could be better understood by looking at the relationship between BP and IS alone. It then proposes an alternative simulation framework, namely ISBPS, that provides the means to develop simulation models that portray quantifiable metrics of the integration of BP and IS, offering in this way an alternative mechanism that can help BP and IS analyst to foresee the benefits that the insertion of a given IS design may bring to the organisational processes

Statistical properties and economic implications of Jump-Diffusion Processes with Shot-Noise effects

This paper analyzes the Shot-Noise Jump-Diffusion model of Altmann, Schmidt and Stute (2008), which introduces a new situation where the effects of the arrival of rare, shocking information to the financial markets may fade away in the long run. We analyze several economic implications of the model, providing an analytical expression for the process distribution. We also prove that certain specifications of this model can provide negative serial persistence. Additionally, we find that the degree of serial autocorrelation is related to the arrival and magnitude of abnormal information. Finally, a GMM framework is proposed to estimate the model parameters

A distributional checklist of the leaf-cutting bees (Hymenoptera: Megachilidae) of Florida

The leaf-cutting bees are a diverse group which is commonly encountered all across the country. With over 600 North American species, most of which are in the genera Anthidium, Dianthidium, Stelis, Heriades, Hoplitis, Osmia, Megachile and Coelioxys, there are numerous “non-Apis” pollinators. Being an important taxon, there is a definite need for an awareness of their distribution across the United States and, perhaps in time, everywhere. This may allow us to follow the establishment of exotic species such as Megachile [Callomegachile] torrida Smith, M. [Pseudomegachile] lanata Fabricius, and an unidentified exotic which is listed below in the subgenus Callomegachile