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Publicações

2017

Mapping the Impact of Daytime and Overnight Electric Vehicle Charging on Distribution Grids

Autores
Heymann, F; Miranda, V; Neyestani, N; Soares, FJ;

Publicação
2017 IEEE VEHICLE POWER AND PROPULSION CONFERENCE (VPPC)

Abstract
Strong adoption dynamics of private passenger electric vehicles (EV) will require adjustments in the operation and planning of electrical distribution grids. This work proposes a novel approach to assess the impact of electric vehicle charging while considering EV adoption dynamics and commuting patterns. The proposed model uses Geographic Information Systems (GIS) and is applied to a real-world case study. Results suggest that clustering of EV charging will occur and underline the relevance of accurate spatial and temporal charging pattern estimations for distribution grid planning. Overloading of distribution network elements was observed even under light EV penetration rates.

2017

Certified Password Quality

Autores
Ferreira, JF; Johnson, SA; Mendes, A; Brooke, PJ;

Publicação
Lecture Notes in Computer Science - Integrated Formal Methods

Abstract

2017

How the performance of a biological pre-oxidation step can affect a downstream photo-Fenton process on the remediation of mature landfill leachates: Assessment of kinetic parameters and characterization of the bacterial communities

Autores
Silva, TFCV; Vieira, E; Lopes, AR; Nunes, OC; Fonseca, A; Saraiva, I; Boaventura, RAR; Vilar, VJP;

Publicação
SEPARATION AND PURIFICATION TECHNOLOGY

Abstract
The main purpose of this work was to assess the (i) short-term effect of the main nitrification and denitrification variables on the nitrogen's biological removal via nitrite from highstrength leachates, and (ii) the effect of the presence/absence of nitrites/nitrates in a downstream photo-oxidation process. The biological reaction rates were evaluated as a function of several parameters: (i) temperature, dissolved oxygen (DO) concentration and pH, on the nitrification; and (ii) pH, temperature and the addition of phosphate ions, on the denitrification. At the beginning of most nitrification assays, it was verified that the ammonia stripping occurred simultaneously to the nitrification, reaching up to 31% removal of total dissolved nitrogen. The maximum nitrification rate obtained was 37 +/- 2 mg NH4+-N/(h.g VSS) (25 degrees C, 1.02.0 mg O-2/L, pH not controlled), consuming 5.3 +/- 0.4 mg CaCO3/mg NH4+-N. The highest denitrification rate achieved was 27 +/- 1 mg NO2--N/(h.g VSS) (pH between 7.5 and 8.0, 30 degrees C, adding 30 mg PO43-/L), with a C/N consumption ratio of 1.6 +/- 0.1 mg CH3OH/mg. NO2--N and an overall alkalinity production of 3.2 +/- 0.1 mg CaCO3/mg NO2--N. The denitrification process showed to be sensitive to all studied parameters, while the nitrification reaction did not suffered significant change when DO content was changed. The two most abundant bacterial groups in the nitrification and denitrification processes, as indicated by the 454-pyrosequencing analysis of the 16S rRNA gene, were affiliated to Saprospiraceae/Nitrosomonadaceae and Hyphomicrobiaceae/Saprospiraceae, respectively. The abundance of Nitrosomonadaceae and Hyphomicrobiaceae (in particular, Hyphomicrobium) in the nitrification and denitrification process, respectively, is in agreement with the nitrifying and denitrifying activity of these bacterial members. The photo-Fenton reaction rate was assessed considering the presence of nitrites and nitrates and the absence of both in a leachate after biological oxidation and coagulation/sedimentation steps. The results showed that for a pre-treated leachate without nitrogen, the DOC degradation rate decreased 28%, while for a bio-treated leachate containing nitrites, the H2O2 consumption was 2.4 times higher.

2017

VitalLogger: An Adaptable Wearable Physiology and Body-Area Ambiance Data Logger for Mobile Applications

Autores
Dias, D; Ferreira, N; Cunha, JPS;

Publicação
2017 IEEE 14TH INTERNATIONAL CONFERENCE ON WEARABLE AND IMPLANTABLE BODY SENSOR NETWORKS (BSN)

Abstract
Current mobile revolution is leading to an increase of wearable health devices development and consequently a growth in ambulatory monitoring area. These systems can be applied in ambulatory diseases management and diagnosis, personal health monitoring or sports performance enhancement, providing physiological and body-area ambiance data during daily normal activities. Nowadays several devices in the market have this type of technology, being one of them the VitalJacket (R) (VJ (R)), a product from Biodevices, S.A. This device is a medical certified smart t-shirt with textile embedded electronics for ambulatory monitoring of electrocardiogram (ECG), Heart Rate (HR) and Accelerometer (Acc) data that is in the market since 2008. In this work we report the result of a university-company joint R&D effort that aimed to propose a reference extension architecture - called VitalLogger - for VJ (R) wearable health device that enables sensors seamless "plug-in" to the company product. As a proof of concept of this novel adaptable architecture, we jointly implemented a prototype that extends VJ (R) technology to incorporate new sensing modules in a seamless way. Both hardware and firmware were re-designed and extended to create a reference extension architecture, enabling easy integration of different sensing modules according to the user monitoring preference/scenario. Besides the ECG module already incorporated in VJ (R), a module with a Blood Oxygen Saturation (SpO2) sensor and an ambiance temperature and relative humidity sensor was developed and added to the extended prototype VitalLogger. This prototype was successfully built and tested, showing excellent results. The VitalLogger adaptable extension architecture has shown its scalability by enabling seamless "plug-in" sensing modules thus creating the possibility of swift creations of new products with different sensors combinations to adapt to different monitoring scenarios.

2017

Certified Password Quality - A Case Study Using Coq and Linux Pluggable Authentication Modules

Autores
Ferreira, JF; Johnson, SA; Mendes, A; Brooke, PJ;

Publicação
Integrated Formal Methods - 13th International Conference, IFM 2017, Turin, Italy, September 20-22, 2017, Proceedings

Abstract
We propose the use of modern proof assistants to specify, implement, and verify password quality checkers. We use the proof assistant Coq, focusing on Linux PAM, a widely-used implementation of pluggable authentication modules for Linux. We show how password quality policies can be expressed in Coq and how to use Coq’s code extraction features to automatically encode these policies as PAM modules that can readily be used by any Linux system. We implemented the default password quality policy shared by two widely-used PAM modules: pam_cracklib and pam_pwquality. We then compared our implementation with the original modules by running them against a random sample of 100,000 leaked passwords obtained from a publicly available database. In doing this, we demonstrated a potentially serious bug in the original modules. The bug was reported to the maintainers of Linux PAM and is now fixed. © Springer International Publishing AG 2017.

2017

Labeled Homomorphic Encryption: Scalable and Privacy-Preserving Processing of Outsourced Data

Autores
Barbosa, Manuel; Catalano, Dario; Fiore, Dario;

Publicação
IACR Cryptology ePrint Archive

Abstract

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