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Publications

Publications by HumanISE

2020

Next generation of microservices for the 5G Service-Based Architecture

Authors
Moreira, JB; Mamede, H; Pereira, V; Sousa, B;

Publication
INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT

Abstract
The architecture for 5G core includes a Service-Based Architecture for the diverse network functions (NFs), which relies on HTTP/2 for the SBI and TCP as the underlying transport protocol. The specifications of the HTTP family is moving towards more efficient and secure protocols, which are based on UDP to assure enhanced transport but using TLS to secure the communication channel. The next generation of microservices needs to be more secure, performant and easily manageable, where HTTP/3 and containers orchestration platforms (like Kubernetes) can provide significative contributions towards such goals. Different deployment approaches can be followed for services implemented in compliance to the 5G SBA. This paper contributes with the assessment of deployment models for services in 5G networks, where NFs are implemented following traditional architectures (all the functions in a VM) or as serverless architectures (with functions distributed in containers). The performance of microservices in Kubernetes is also evaluated. The evaluation conducted also considers the employment of different versions of HTTPs to empower the service-based interfaces of 5G services. Results demonstrate performance benefits of employing HTTP/3, based on QUIC protocol, in scenarios with networks characterised by losses or delay conditions. Despite such gain, deployment in 5G networks needs to carefully consider aspects related with connection tracking mechanisms to support high volumes of requests.

2020

Managing millennials as outsourced information technology professionals: A systematic review

Authors
França, TJF; Mamede, HS; Dos Santos, VD;

Publication
Proceedings of the 13th IADIS International Conference ICT, Society and Human Beings 2020, ICT 2020 and Proceedings of the 6th IADIS International Conference Connected Smart Cities 2020, CSC 2020 and Proceedings of the 17th IADIS International Conference Web Based Communities and Social Media 2020, WBC 2020 - Part of the 14th Multi Conference on Computer Science and Information Systems, MCCSIS 2020

Abstract
The Information Technology Outsourcing (ITO) model has been a trend in recent decades, becoming the dominant trend in contemporary outsourcing scenario. Millennials will soon, globally, be the majority of the workforce, having a particular way of relating to organizations and to work itself as no previous generation did. Information technologies continue to employ more and more human resources, having an increasing demand and a shortage of competent resources. It is therefore important to rethink current Human Resources Management (HRM) models and design a new strategic and appropriate model to accommodate and anticipate the needs of managers and monitor the development of this generation as Information Technology (IT) professionals. The intersection and analysis of the Information and Communications Technologies (ICT), millennials, Human Resource Management, outsourcing and organizations is the objective of this study, to identify the most relevant articles regarding millennials as outsourced IT professionals.

2020

Simplified methodology for the practice of business architecture in smes [Metodologia Simplificada para a Prática de Arquitetura Empresarial em PME]

Authors
Mamede, HS; Correia, J;

Publication
Atas da Conferencia da Associacao Portuguesa de Sistemas de Informacao

Abstract
The current context of organizations has meant that their business models have been continually evolving, creating opportunities for technological innovations. Business strategies become a significant challenge, mainly if organizations are small or medium-sized, with all the constraints typically associated with them. The most used digital transformation frameworks are centered on large organizations and those that until now have been proposed for application in smaller organizations present some questions. In this article, a new methodology proposal, SimpliSMEEA, is presented and its application to a specific company is described and evaluated. © Atas da Conferencia da Associacao Portuguesa de Sistemas de Informacao 2020.

2020

The Structure of Climate Variability Across Scales

Authors
Franzke, CLE; Barbosa, S; Blender, R; Fredriksen, HB; Laepple, T; Lambert, F; Nilsen, T; Rypdal, K; Rypdal, M; Scotto, MG; Vannitsem, S; Watkins, NW; Yang, LC; Yuan, NM;

Publication
REVIEWS OF GEOPHYSICS

Abstract
One of the most intriguing facets of the climate system is that it exhibits variability across all temporal and spatial scales; pronounced examples are temperature and precipitation. The structure of this variability, however, is not arbitrary. Over certain spatial and temporal ranges, it can be described by scaling relationships in the form of power laws in probability density distributions and autocorrelation functions. These scaling relationships can be quantified by scaling exponents which measure how the variability changes across scales and how the intensity changes with frequency of occurrence. Scaling determines the relative magnitudes and persistence of natural climate fluctuations. Here, we review various scaling mechanisms and their relevance for the climate system. We show observational evidence of scaling and discuss the application of scaling properties and methods in trend detection, climate sensitivity analyses, and climate prediction.

2020

Ambient radioactivity and atmospheric electric field: A joint study in an urban environment

Authors
Barbosa, S;

Publication
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY

Abstract
Ambient radioactivity and atmospheric electricity are inextricably linked phenomena. In order to assess the role of ambient radioactivity in the local variability of the atmospheric electric field at an urban site, simultaneous measurements of radon concentration, gamma radiation, and atmospheric electric field are carried out in the city of Porto, Portugal. Both radon and gamma radiation display an average daily cycle peaking before sunrise, but with considerable variability from day to day, particularly in amplitude. The atmospheric electric field displays a daily cycle with a minimum at dawn and maximum in the early afternoon, as well as a secondary peak in the early morning. The temporal variation of the daily patterns is analysed by means of an empirical orthogonal function analysis, and related to local meteorological parameters. The variability of the local atmospheric electric field is mainly determined by aerosol transport and accumulation close to the surface associated with local meteorological conditions and atmospheric stability rather than by conductivity variations associated with ambient radioactivity.

2020

Morphological controls and statistical modelling of boulder transport by extreme storms

Authors
Oliveira, MA; Scotto, MG; Barbosa, S; de Andrade, CF; Freitas, MD;

Publication
MARINE GEOLOGY

Abstract
The study of coastal boulder accumulations generated by extreme marine events, and of the energy and frequency involved in boulder transport, is of paramount importance in understanding the risk associated with extreme marine inundations. One of the frequently asked questions is whether the deposits are storm or tsunami-related, both events being characterized by different return periods. Boulder transport by storms was monitored on the west coast of Portugal. Significant changes were detected in boulders' position as a result of extreme inundation by the 2013/2014 winter storms. Results presented in this work indicate that the wave power associated with the "Christina" and "Nadja" storms occur once every three years. However, this interval is not supported by field observations of boulder displacement, which suggests that wave power over-predicts boulder movement in the study area. Furthermore, wave parameters from the "Christina" and "Nadja" storms were very similar, but have generated different impacts in the boulder accumulation described herein. Differences include the magnitude and direction of boulder movement, and are most likely associated with distinct tidal levels during the events. Higher tide levels generated an increase in the sea surface level and thus in the reach of waves, which generated displacement of larger boulders and consequent cross-shore contribution in boulder transport. Regardless, the combination of monitoring campaigns, wave data, and statistical modelling of extreme values indicate that boulder transport by storms is more frequent than initially expected. Based on recorded boulder movements, we present a conceptual model for boulder ridge formation and development and identify significant control of incoming flow by local geomorphological/topographical features. Storm events, not less frequent tsunamis, are identified as the events responsible for modulating this rocky coastline. These results question a direct attribution of coastal boulder deposits to tsunamis in coastal regions with a high risk of tsunami inundation.

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