4,543 research outputs found
Logic of agreement: Foundations, semantic system and proof theory
AbstractIn this paper a multi-valued propositional logic — logic of agreement — in terms of its model theory and inference system is presented. This formal system is the natural consequence of a new way to approach concepts as commonsense knowledge, uncertainty and approximate reasoning — the point of view of agreement. Particularly, it is discussed a possible extension of the Classical Theory of Sets based on the idea that, instead of trying to conceptualize sets as “fuzzy” or “vague” entities, it is more adequate to define membership as the result of a partial agreement among a group of individual agents. Furthermore, it is shown that the concept of agreement provides a framework for the development of a formal and sound explanation for concepts (e.g. fuzzy sets) which lack formal semantics. According to the definition of agreement, an individual agent agrees or not with the fact that an object possesses a certain property. A clear distinction is then established, between an individual agent — to whom deciding whether an element belongs to a set is just a yes or no matter — and a commonsensical agent — the one who interprets the knowledge shared by a certain group of people. Finally, the logic of agreement is presented and discussed. As it is assumed the existence of several individual agents, the semantic system is based on the perspective that each individual agent defines her/his own conceptualization of reality. So the semantics of the logic of agreement can be seen as being similar to a semantics of possible worlds, one for each individual agent. The proof theory is an extension of a natural deduction system, using supported formulas and incorporating only inference rules. Moreover, the soundness and completeness of the logic of agreement are also presented
An IT value management capability model for portuguese universities: a Delphi study
One of the most common dilemmas faced today by organizations and their leaders is how to guarantee value from high level IT investments, i.e. how organizations ensure expected benefits from growth in IT investments. Knowledgeable about this reality, organizations seek solutions to solve this problem, either through the adoption of frameworks developed and proposed by the professional community (COBIT5; VAL IT 2.0; IT-CMF), or alternatively, by designing and implementing their own models. The aforementioned, for organizations in general, is not different in the context of Higher Education Institutions (HEIs). This paper adopts a Resource-Based View theory (RBV) to identify a set of competences and resources, which contribute to develop and conceptualize an IT Value Management Capability Model. The identified items were submitted to a panel of experts through a Delphi study in order to validate and propose a baseline to assist academic and practitioners understand essential requirements to implement an IT Value Management Capability Model (ITVMCM) in Portuguese public universities.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013
Online data reliability for monitoring tourism activities in cities
Studying the spatial structure of destinations has long been considered an important topic on tourism research. Researchers focus their attention on the analysis of tourism consumption and production. Recent studies found that non-traditional data, either from social media or peer-to-peer digital platforms, is useful for managing and monitoring tourism activities on dynamic destinations such as cities. However, more research is needed to address data reliability since it is important to understand the strengths and limitations of this novel data. This paper compares visitor counts to Lisbon city identified by their digital footprints on social media (i.e., visitors’ geotagged photos from Flickr) with official hotel occupancy rates, as well as the accommodation supply from Airbnb listings with local accommodation official statistics. Findings demonstrated that the number of visitors identified by their digital footprints matches relatively well the visitation pattern reproduced by hotel occupancy rates. Datasets representing the accommodation supply uncovered the spatial concentration of local lodgings, not exclusively in the well-known tourist areas. Despite the strong correlation between datasets, there are some areas where the lodging counts deviate significantly, as we move from the periphery to tourism cores. Results showed the value of data from social media and peer-to-peer digital platforms as proxy for monitoring city tourism activities.info:eu-repo/semantics/publishedVersio
At the foot of a tree: the study of African cosmoperceptions in Mia Couto
The text intends to analyze the trees as a symbolic element linked to African cosmoperceptions of the sacred, traditions, ancestry and time, present in the work “A Varanda do Frangipani”, by Mia Couto. The approach in African literature reveals that the physical representations of nature bring us closer to the cosmological universe of the past and present. In the first part, we present the vital force of trees and the power of African-Mozambican cultures. In the second, we analyze African cosmoperceptions and what “the trees” teach us in Coutiana's work. We dare to say that, when crossing walls and worlds through the word and imagination, with whole bodies and souls, we are Africanized!: O texto pretende analisar as árvores como elemento simbólico ligado às cosmopercepções africanas do sagrado:tradições, ancestralidade e tempo, presentes na obra “A Varanda do Frangipani”, de Mia Couto. A abordagem na literatura africana, revela que as representações físicas da natureza nos aproximam do universo cosmológico do passado e do presente. Na primeira parte, apresentamos a força vital das árvores e o poder das culturas africano-moçambicanas. Na segunda, analisamos as cosmopercepções africanas e o que nos ensinam “as árvores” na obra coutiana. Arriscamos dizer que, ao atravessarmos muros e mundos pela palavra e imaginação, com corpos e almas inteiros, nos africanizamos!
Simulação dinâmica de estratégias para conforto térmico usando materiais de mudança de fase
Mestrado em Engenharia CivilNowadays, as global warming becomes one of the most urgent problems in the world, there is a need to find better ways to utilize energy: not only in the field of energy production, transmission, distribution, and consumption, but also in the area of energy storage. With energy storage technologies, it is possible to overcome the contradiction between the energy production and consumption, alleviate the tense production load of power plants at peak hours, and reduce consumers’ electricity costs by avoiding higher peak hour tariffs.
Thermal energy storage, or heat and cold storage, allows the storage of heat or cold to be used later. This method needs to be reversible so it allows for multiple cycles. The technology that was studied for this effect was Phase Change Materials or PCMs.
With that in mind, and with the help of dynamic building simulation software, EnergyPlus, several scenarios of an existing build that has PCM incorporated were studied in order to ascertain the real effect the technology is having on the case study, including thermal comfort.Hoje em dia, com o aquecimento global a tornar-se um dos problemas mais urgentes da Terra, há necessidade de encontrar melhores maneiras de utilizar energia: não apenas no campo da produção de energia, transmissão, distribuição e consumo, mas também na área de armazenamento de energia. Com tecnologias de armazenamento de energia, é possível de ultrapassar a contradição entre a produção e consumo, aliviar a tensão que existe na produção nas estações de energia nas horas de pico e reduzir o custo de electricidade aos utentes ao evitar as tarifas nas horas de pico.
A armazenagem de energia calorífica, do calor e frio, permite o armazenamento de calor ou frio para ser usado mais tarde. Este método precisa de ser reversível para permitir vários ciclos deste processo. A tecnologia estudada para este efeito foi os materiais que mudam de fase, ou PCMs (Phase Change Materials).
Com isto em mente, e com a ajuda de software de simulação dinâmica, EnergyPlus, vários cenários de um edifício existente que tem PCM incorporado foram estudados em ordem de poder concluir o verdadeiro efeito que a tecnologia está a ter no caso estudo, incluindo o conforto térmico
A Distributed Sensor Data Search Platform for Internet of Things Environments
Recently, the number of devices has grown increasingly and it is hoped that,
between 2015 and 2016, 20 billion devices will be connected to the Internet and
this market will move around 91.5 billion dollars. The Internet of Things (IoT)
is composed of small sensors and actuators embedded in objects with Internet
access and will play a key role in solving many challenges faced in today's
society. However, the real capacity of IoT concepts is constrained as the
current sensor networks usually do not exchange information with other sources.
In this paper, we propose the Visual Search for Internet of Things (ViSIoT)
platform to help technical and non-technical users to discover and use sensors
as a service for different application purposes. As a proof of concept, a real
case study is used to generate weather condition reports to support rheumatism
patients. This case study was executed in a working prototype and a performance
evaluation is presented.Comment: International Journal of Services Computing (ISSN 2330-4472) Vol. 4,
No.1, January - March, 201
Contribution to Local Landscape Units definition in OTALEX II
OTALEX II is the Territorial and Environmental Observatory of Alentejo (Portugal) and Extremadura (Spain),
co-financed by POCTEP, developed with the cross-border collaboration of several Portuguese and Spanish bodies. It is
composed of a Spatial Data Infrastructure (SDI) created in 2007, SDI-OTALEX (www.ideotalex.eu), which is an
exchange platform for geographic information and Webmapping services among project partners. The integration of environmental
indicators such as landscape indicators, for the characterization and monitoring of the Alentejo Extremadura
area is one of the most relevant components of the project. This paper reports the achievements in defining Local Landscape
Units (LLU) for a pilot area of Central Alentejo – the Pardiela river basin. The methodological approach applied
Geographic Information System tools to integrate soils, geomorphology and land cover. The land cover map applies the
CORINE Land Cover Legend Level 5 to Central Alentejo at a scale of 1 : 10,000. This map contains variables related to
vegetation, hydrology (streams and water bodies) and human settlements (buildings, equipment, roads). The validation
of the results obtained for LLU with previously defined Landscape Units and potential vegetation mapping confirm the
reliability and replicability of the present methodology for similar territories
Identifying tourist places of interest based on digital imprints: towards a sustainable smart city
As cities become increasingly complex, Information and Communication Technologies
(ICTs) bring smartness into organisations and communities, contributing to a more competitive
tourism destination, i.e., smart tourism destinations. Enhanced information access coupled with a
new kind of tourists avid for online content and predisposed to share information on social media,
allows for a better understanding of tourist behaviour regarding their spatial distribution in urban
destinations. Thus, smart tourism portrays individuals as information makers, refining the available
alternatives for tracking their location. Big data analytics is a technology with the potential to develop
Smart City services. From the analysis of the spatial distribution of tourists in the city of Lisbon based
on data collected from the ‘Panoramio’ social network, we identify the most popular places in the
city in a context of tourist visits. This new data largely contributes to understanding the consumption
of space within urban tourist destinations and therefore enables us to differentiate the overcrowded
places from the ones with potential to grow. This allows decision-makers to imagine new ways of
planning and managing towards a sustainable ‘smart’ future.info:eu-repo/semantics/publishedVersio
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