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Publications

2018

Assessing the importance of transportation activity data for urban emission inventories

Authors
Dias, D; Amorim, JH; Sa, E; Borrego, C; Fontes, T; Fernandes, P; Pereira, SR; Bandeira, J; Coelho, MC; Tchepel, O;

Publication
TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT

Abstract
The aim of this research is the implementation of a GPS-based modelling approach for improving the characterization of vehicle speed spatial variation within urban areas, and a comparison of the resulting emissions with a widely used approach to emission inventory compiling. The ultimate goal of this study is to evaluate and understand the importance of activity data for improving the road transport emission inventory in urban areas. For this purpose, three numerical tools, namely, (i) the microsimulation traffic model (VISSIM); (ii) the mesoscopic emissions model (TREM); and (iii) the air quality model (URBAIR), were linked and applied to a mediumsized European city (Aveiro, Portugal). As an alternative, traffic emissions based on a widely used approach are calculated by assuming a vehicle speed value according to driving mode. The detailed GPS-based modelling approach results in lower total road traffic emissions for the urban area (7.9, 5.4, 4.6 and 3.2% of the total PM10, NOx, CO and VOC daily emissions, respectively). Moreover, an important variation of emissions was observed for all pollutants when analysing the magnitude of the 5th and 95th percentile emission values for the entire urban area, ranging from -15 to 49% for CO, -14 to 31% for VOC, -19 to 46% for NOx and -22 to 52% for PM10. The proposed GPS-based approach reveals the benefits of addressing the spatial and temporal variability of the vehicle speed within urban areas in comparison with vehicle speed data aggregated by a driving mode, demonstrating its usefulness in quantifying and reducing the uncertainty of road transport inventories.

2018

Impact of the Stochastic Behaviour of Distributed Energy Resources on MV/LV Network Reliability

Authors
Ndawula M.B.; Hernando-Gil I.; Djokic S.;

Publication
Proceedings - 2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe, EEEIC/I and CPS Europe 2018

Abstract
This paper presents an integrated approach for assessing the impact that distributed energy resources (DERs), mostly intermittent in nature, might have on the reliability performance of distribution networks. A test distribution system based on a typical MV/LV urban distribution network in the UK is fully modelled and controlled to investigate the potential benefits that local renewables and energy storage can offer to the quality of power supply to customers. In this analysis, the conventional Monte Carlo method is further developed to include the time-variation of electricity demand profiles and failure rates of network components. Additionally, a theoretical interruption model is employed to assess more accurately the moment in time when interruptions to electricity customers are likely to occur. Accordingly, the impact of the spatio-temporal variation of DERs, with photovoltaic (PV) systems as key enablers, is quantified in terms of the effect of network outages. A range of smart grid functionalities is analysed and their benefits are assessed through standard reliability indices, with special attention to energy not supplied to customers, as well as frequency and duration of supply interruptions.

2018

A mathematical model for collecting and distributing perishable products by considering costs minimisation and CO<inf>2</inf> emissions

Authors
Tordecilla-Madera R.; Roa A.P.; Escobar J.W.; Buriticá N.C.;

Publication
International Journal of Services and Operations Management

Abstract
This paper considers the problem of allocating vehicles to collect and distribute fruit to producer associations in Colombia. In particular, the problem seeks to determine the optimal allocation of vehicles for fruit collection minimising both total transportation costs and CO2 emissions. This problem has multiple objectives, and the well-known e-constraint method has been used as solution technique for the proposed mathematical models. The efficiency of the former methodology has been tested by using a case study involving the distribution of blackberry (Rubus glaucus) by an association of producers in Cundinamarca Department, Colombia. In particular, we considered 12 different scenarios related to supply levels, route outsourcing, and collection frequency. The results show the efficiency of the proposed methodology in solving vehicle allocation problems related to collection and distribution. The case study reveals that, in general, collecting fruit three days/week yields lower costs and fewer emissions than performing collections four days/week. Furthermore, increased supply leads to greater differences between costs and emissions.

2018

The relationship between leadership style and the success of Lean management implementation

Authors
da Costa Nogueira, DMD; Sousa, PSA; Moreira, MRA;

Publication
LEADERSHIP & ORGANIZATION DEVELOPMENT JOURNAL

Abstract
Purpose The purpose of this paper is to better understand the role that leadership plays in the success of Lean management (LM) implementation, by trying to identify what is the impact of the transactional, transformational, directive and empowering leadership styles on the success of such an implementation in Portuguese companies, and what are the most important leaders' attributes. Design/methodology/approach An on-line questionnaire was distributed to 65 manufacturing and services Portuguese organizations that have implemented LM. Findings The results suggest that the empowering leadership style has a positive impact on the success of LM implementation. Even though results do not allow concluding about the impact of the other styles, several leader's attributes were identified as having influence: individualized consideration, information sharing, skill development, intellectual stimulation, assigned goals and self-directed decision making. Originality/value Very few studies have addressed the role of leadership in the success of adopting LM and, to the best knowledge, only one paper studied the critical attributes of leaders in LM implementation. Moreover, the present study focuses in Portugal, country where this topic has rarely been investigated.

2018

Fully Automatic Assessment of Mitral Valve Morphology from 3D Transthoracic Echocardiography

Authors
Pedrosa, J; Queiros, S; Vilaca, J; Badano, L; D'hooge, J;

Publication
2018 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS)

Abstract
Quantitative assessment of mitral valve (MV) morphology is important for diagnosing MV pathology and for planning of reparative procedures. Although this is typically done using 3D transesophageal echocardiography (TEE), recent advances in the spatiotemporal resolution of 3D transthoracic echocardiography (TTE) have enabled the use of this more patient friendly modality. However, manual data analysis is time consuming and operator dependent. In this study, a fully automatic method for MV segmentation and tracking in 3D TTE is proposed and validated. The proposed framework takes advantage of a previously proposed left ventricle (LV) segmentation framework to localize the MV and performs segmentation based on the B-spline Explicit Active Surfaces (BEAS) framework. The orientation of the MV is obtained and the MV surface is cropped to the mitral annulus (MA) and divided into posterior and anterior leaflets. The segmented MV at end diastole (ED) is propagated to end systole (ES) using localized anatomical affine optical flow (lAAOF). Because the orientation and leaflet division is known, relevant clinical parameters can then be extracted from the mesh at any time point. The proposed framework shows excellent segmentation results with a mean absolute distance (MAD) and Hausdorff distance (HD) of 1.19 +/- 0.25 mm and 5.79 +/- 1.25 mm at ED and 1.39 +/- 0.32 mm and 6.70 +/- 1.97 mm at ES against manual analysis. In conclusion, an automatic method for MV segmentation is proposed which could provide valuable clinical information in a more patient-friendly manner.

2018

Color Algorithm for Flame Exposure (CAFE)

Authors
Alves, J; Soares, C; Torres, J; Sobral, P; Moreira, RS;

Publication
2018 13TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
Panoramic or aerial images can be acquired with some easiness and cover vast tracts of territory to be used in fire detection. The analysis of these images, in particular based on color and threshold indices, can be very interesting computationally when applied in real time systems and collected, for example, through drones or watchtowers. This paper presents a solution designated Color Algorithm for Flame Exposure (CAFE), which significantly improves an existing method (cf. Forest Fire Detection Index - FFDI) in flame detection, based on daylight images, in mixed Mediterranean landscape, containing vegetation, buildings, burning areas, land, etc. The CAFE approach, presented, adds a parameterizable transformation of the image into the Lab color space. This approach was tested in four distinct scenarios, significantly reducing false positives and maintaining an equivalent level of false negatives when compared to the FFDI approach.

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