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Publicações

2015

Distribution System Reconfiguration with Variable Demands Using the Clonal Selection Algorithm

Autores
Frutuoso de Souza, SSF; Romero, R; Correia Pereira, JMC; Tome Saraiva, JPT;

Publicação
2015 18TH INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEM APPLICATION TO POWER SYSTEMS (ISAP)

Abstract
This paper describes the application of the clonal selection algorithm to the reconfiguration problem of distribution networks considering non-uniform demand levels. The Clonal Algorithm, CLONALG, is a combinatorial optimization technique inspired in the immunologic bio system and it aims at reproducing the main properties and functions of this system. The reconfiguration problem of distribution networks with non-uniform demand levels is a complex problem that aims at identifying the most adequate radial topology of the network that complies with all technical constraints in every demand level while minimizing the cost of active losses along an extended operation period. This work includes results of the application of the Clonal algorithm to distribution systems with 33, 84 and 136 buses. These results demonstrate the robustness and efficiency of the proposed approach.

2015

The trust-commitment challenge in service quality-loyalty relationships

Autores
Moreira, AC; Silva, PM;

Publicação
INTERNATIONAL JOURNAL OF HEALTH CARE QUALITY ASSURANCE

Abstract
Purpose - The purpose of this paper is to develop and empirically test a model to examine service quality, satisfaction, trust and commitment as loyalty antecedents in a private healthcare service. Design/methodology/approach - The approach was tested using structural equation modelling, involving 175 patients from a private Portuguese healthcare unit, using a revised Service Quality Assessment Scale (SQAS) scale for service quality evaluation. Findings - The scale used to evaluate service quality is valid and meaningful. Service quality proved to be a multidimensional construct and relevant to build satisfaction. The path satisfaction -> trust -> loyalty was validated, whereas the path satisfaction -> commitment -> loyalty was not statistically supported. Research limitations/implications - The revised SQAS scale showed good internal consistency in healthcare context. Further trust-commitment antecedents must be examined in a private healthcare landscape to generalise the findings. Practical implications - Healthcare quality managers must explore the service quality dimensions to generate satisfaction among their patients. Developing trust generates positive patient attitudes and loyalty. Originality/value - This study explores using the SQAS scale in a private healthcare context. The authors provide further evidence that service quality is an antecedent and different from satisfaction. All the measures used proved to be valid and reliable. Trust and commitment play different roles in their relationship with loyalty.

2015

On the anodic aluminium oxide refractive index of nanoporous templates

Autores
Hierro Rodriguez, A; Rocha Rodrigues, P; Valdes Bango, F; Alameda, JM; Jorge, PAS; Santos, JL; Araujo, JP; Teixeira, JM; Guerreiro, A;

Publicação
JOURNAL OF PHYSICS D-APPLIED PHYSICS

Abstract
In the present study, we have determined the intrinsic refractive index of anodic aluminium oxide, which is originated by the formation of nanoporous alumina templates. Different templates have been fabricated by the conventional two-step anodization procedure in oxalic acid. Their porosities were modified by chemical wet etching allowing the tuning of their effective refractive indexes (air-filled nanopores + anodic aluminium oxide). By standard spectroscopic light transmission measurements, the effective refractive index for each different template was extracted in the VIS-NIR region. The determination of the intrinsic anodic aluminium oxide refractive index was performed by using the Maxwell-Garnett homogenization theory. The results are coincident for all the fabricated samples. The obtained refractive index (similar to 1.55) is quite lower (similar to 22%) than the commonly used Al2O3 handbook value (similar to 1.75), showing that the amorphous nature of the anodic oxide structure strongly conditions its optical properties. This difference is critical for the correct design and modeling of optical plasmonic metamaterials based on anodic aluminium oxide nanoporous templates.

2015

Multimodal inverse perspective mapping

Autores
Oliveira M.; Santos V.; Sappa A.D.;

Publicação
Information Fusion

Abstract
Over the past years, inverse perspective mapping has been successfully applied to several problems in the field of Intelligent Transportation Systems. In brief, the method consists of mapping images to a new coordinate system where perspective effects are removed. The removal of perspective associated effects facilitates road and obstacle detection and also assists in free space estimation. There is, however, a significant limitation in the inverse perspective mapping: the presence of obstacles on the road disrupts the effectiveness of the mapping. The current paper proposes a robust solution based on the use of multimodal sensor fusion. Data from a laser range finder is fused with images from the cameras, so that the mapping is not computed in the regions where obstacles are present. As shown in the results, this considerably improves the effectiveness of the algorithm and reduces computation time when compared with the classical inverse perspective mapping. Furthermore, the proposed approach is also able to cope with several cameras with different lenses or image resolutions, as well as dynamic viewpoints.

2015

Survey of Temporal Information Retrieval and Related Applications

Autores
Campos, R; Dias, G; Jorge, AM; Jatowt, A;

Publicação
ACM COMPUTING SURVEYS

Abstract
Temporal information retrieval has been a topic of great interest in recent years. Its purpose is to improve the effectiveness of information retrieval methods by exploiting temporal information in documents and queries. In this article, we present a survey of the existing literature on temporal information retrieval. In addition to giving an overview of the field, we categorize the relevant research, describe the main contributions, and compare different approaches. We organize existing research to provide a coherent view, discuss several open issues, and point out some possible future research directions in this area. Despite significant advances, the area lacks a systematic arrangement of prior efforts and an overview of state-of-the-art approaches. Moreover, an effective end-to-end temporal retrieval system that exploits temporal information to improve the quality of the presented results remains undeveloped.

2015

The assessment of cities' livability integrating human wellbeing and environmental impact

Autores
Zanella, A; Camanho, AS; Dias, TG;

Publicação
ANNALS OF OPERATIONS RESEARCH

Abstract
This study develops a tool to assess livability in European cities covering two components of livability: human wellbeing and environmental impact. First, we propose a conceptual model to assess cities' livability, that extends the concept of urban livability to include a component related to environmental sustainability. Second, we address the measurement of cities' livability. For this purpose, a new composite indicator was constructed based on a data envelopment analysis model specified using a directional distance function. In addition to assigning a summary measure of performance for each city, the composite indicator can be used to guide improvements concerning different livability objectives. One of the innovative features of the model proposed is to enable, by the specification of different directional vectors, focusing separately on each component of livability (e.g., human wellbeing and environmental impact) or alternatively considering cities' potential for improvement in all indicators simultaneously. In addition, it is possible to incorporate a new type of weight restrictions, specified as assurance regions type I, that reflect the relative importance of both desirable and undesirable outputs in percentage terms. Finally, this paper approached the assessment of the evolution of cities' performance over time using the Luenberger productivity indicator.

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