The purpose driven privacy preservation for accelerometer-based activity recognition

Accelerometer-based activity recognition (AAR) attracted a lot of attentions due to the wide spread of smartphones with energy-efficiency. However, since accelerometer data contains individual characteristics; AAR might raise privacy concerns. Although numerous privacy preservation approaches, such as ”privacy filtering, differential privacy, and inferential privacy”, have been proposed to conceal sensitive information, unfortunately they cannot address the privacy problem associated with AAR. In this paper, we report our efforts to control the use of the AAR while preserving the privacy. To achieve this task, our method leverages a connection to agglomerative information bottleneck, through which the amount of disclosed data can be compressed so that irrelevant private information can be reduced, and a connection to general privacy statistical inference framework, where both of the privacy leakage and utility accuracy are considered as mutual information. Our experimental results have shown that the proposed solution can greatly reduce privacy leakage while maintaining a relative good utility.     

A kernel discriminant analysis for spatially dependent data

Distributed and Parallel Databases - We propose a novel supervised classification algorithm for spatially dependent data, built as an extension of kernel discriminant analysis, that we named...     

Synthesis and Characterization of Bulk Bi-2212 Superconducting Ceramic Using Photopolymerization Reaction-Based Method

Journal of Superconductivity and Novel Magnetism - This study highlights the synthesis of Bi2Sr2CaCu2O8 (Bi-2212) superconducting ceramic using the photopolymerization reaction (PPR) and...     

Magnetic and electrical behaviour of La0.67Ba0.33Mn1 − xFexO3 perovskites

(La_0.67Ba_0.33)Mn_1 ? xFe_xO₃ manganites compounds have been prepared by doping up to 20% of Fe at the Mn site. As previously reported in the literature paramagnetic (PM) to ferromagnetic (FM) phase transition has been observed in materials with low Fe doping (≤ 10%). In our x = 0 and x = 0.05 compounds the Curie temperature (T_C) is close to room temperature. Above 10% Fe amount, specimens exhibit a glass magnetic behaviour with a spin- or cluster-like freezing process that can be related to a loss of ferromagnetic double exchange interaction. Below 10% of Fe³⁺ doping electrical-resistivity measurement shows metal – semiconductor transition with a maximum peak of resistivity (ρ_max) at a temperature T_P close to T_C. Above 10% of Fe³⁺ doping amount the materials exhibit only semiconductor behaviour. Both T_C and T_P decrease with doping rates with an increasing difference in temperature (T_P being lower than T_C). Results are consistent with a reduction of the number of available hopping sites for the Mn e_g(↑) electron due to substitution of Mn³⁺ by Fe³⁺ that suppress the double exchange (DE) interactions.     

Performances and Deactivation of Supported Precious Metal Catalysts in the Oxidation of an Engine Oil Vapour

In this paper, a homemade apparatus was built in order to study the formation of carbonaceous deposits on stainless steel, in order to model the fouling by oil vapours of gas/water heat exchanger used in energy production systems fed with natural gas. Oil vapours were shown to form, at the surface of stainless steel, a varnish layer very difficult to remove, as shown by TPD. One solution to this fouling was shown to be the oxidation of oil vapours by a catalytic system. Pt/alumina and to a lower extend Pd/ceria-alumina catalysts exhibited interesting performances, but we demonstrated that they can be deactivated by the oil vapours, which form a carbonaceous deposit (coke) at their surface. Nevertheless, Pt/alumina can be regenerated by increasing the oxygen amount up to 20 vol% or so during a limited duration and at moderate temperature (450 °C). In order to take benefit of such a regenerative process, it was vital to use non degraded oils, because vapours originating from an aged oil (treated at 300 °C in air) were not likely to be much oxidised to CO₂ and H₂O and therefore coke formed at catalyst’s surface under these conditions cannot be removed by the regenerative treatment under oxygen excess.     

Electrochemical and spectroscopic characterizations of patinas formed on an archaeological bronze coin

A bronze coin datable of the post-Roman empire and discovered in Morocco was studied. The in-depth structure and the composition of both patina and substrate alloy were determined by SEM observations, EDS (elemental dispersion analysis using X-ray) cartographies and Raman spectroscopy on a cross-section. The composition of the patina and that of the substrate alloy were found to be highly heterogeneous. Some patina particles were also scraped off from coin surface. Their electrochemical properties were characterized by cyclic voltammetry and electrochemical impedance spectroscopy with a cavity microelectrode. Cyclic voltammetry revealed the presence of three cathodic current peaks. In situ Raman microspectroscopy on the microelectrode allowed the attribution of two of them to Cu(0)|Cu(I) and Cu(I)|Cu(II). The third one was ascribed to the presence of lead oxide. Moreover, it was observed that tin dioxide initially present in the patina gradually disappeared independently of the potential cycling. This phenomenon was explained by the dissolution of this species through a chemical process. The impedance spectra collected with the cavity microelectrode were simulated suitably with an oxidation-reduction reaction coupled with a hemispherical diffusion model of dissolved oxygen.     

Prediction of micro-explosion delay of emulsified fuel droplets

Burning a water-in-oil emulsion enables reduction in solid and gaseous pollutants in comparison with neat oil. In the emulsion, Heavy Fuel-Oil and water lie in distinct phases, having a high difference in boiling point (up to 200 K). In an emulsion droplet injected and subsequently heated inside a flame, the internal water droplets are enclosed inside the emulsion and do not systematically vaporise at boiling point. They are known to reach a metastable state, breaking up at a temperature below the spinodal limit of water. From this moment, the surrounding Fuel-Oil is fragmented into numerous faster and smaller droplets by the suddenly expanding steam. This physical phenomenon is called “micro-explosion”. This work demonstrates a numerical modelisation of unsteady heat and mass transfer at the surface and inside of the emulsion droplet, and provides a prediction of its micro-explosion delay, using homogeneous nucleation hypothesis. This assumption of homogeneous nucleation for internal water droplets matches the use of a “drop tower” experimental facility. Finally, comparisons between predicted ranges for micro-explosion delays and experimental delays from literature are discussed, along with combustion parameters (ambient temperature, relative velocity) and combustible emulsion parameters. As a result, the experimental and numerical micro-explosion delays decrease with liquid or ambient temperature and relative velocity, and increase with water content and radius of emulsion droplet. Their low average deviation reveals the accuracy of the assumption of homogeneous nucleation in the considered situations.     

Secure and optimal operation of a power generation and transmissionsystem-application to the Moroccan system

This article presents a new method for solving the “optimal power flow” problem in electric power systems. The method is fast and accurate. It has been implemented through two separate optimization models: MODINOP-the initial optimization model-which finds quickly a near optimal solution; and MODFINOP-the final optimization model-which leads to the optimal solution from the initial solution. The initial optimization model uses the principal component of the branch power flows as control variables. The network losses are computed at each optimization step and attached to the branch extremity buses as additional loads. The final optimization model improves the accuracy. It uses the state variable changes as control variables and incorporates the losses in the objective function. The resulting optimization models are solved using linear programming which is easy to implement and provides a fast solution. The utilization of these models with actual data of the Moroccan transmission network operation yield quickly, in a few seconds on a VAX 11/780, accurate results consistent with the real time data and compatible with the results provided by other models     

Intraarticular tolerability and kinetics of gadolinium tetra-azacyclododecane tetraacetic acid

RATIONALE AND OBJECTIVES: We assessed the tolerability and the intraarticular kinetics of gadolinium tetra-azacyclododecane tetraacetic acid (Gd-DOTA) using magnetic resonance (MR) imaging. METHODS: Twelve of 18 dogs received an intraarticular injection of Gd-DOTA solution. Pathologic examination of all joints was performed with assessment of Gd-DOTA bone absorption. Effects of Gd-DOTA on chondrocyte viability and proliferation in vitro were determined using cultures of rabbit chondrocytes. Four dogs underwent MR imaging of the stifle joint before and after intraarticular injection of 0.8 ml Gd-DOTA at a concentration of 2 mmol/l (300 mOsm/l). Intraarticular kinetics of Gd-DOTA were determined from quantitative measurements using repeated sagittal spin-echo T1-weighted images. RESULTS: No microscopic changes of the joints or Gd-DOTA bone absorption were detected. No cytotoxicity for chondrocytes was observed at a concentration of 5 mmol/l, but a decreased cell count was observed at a high concentration (50 mmol/l). The intraarticular Gd-DOTA concentration decreased with time according to a logarithmic curve with an intraarticular half-life of 103-152 min (M = 127 min). CONCLUSION: Gd-DOTA is a safe intraarticular contrast agent with a long half-life in the joint cavity.     

Development of value-added polyethylene grades with extended service lifetime: Weathering resistant flame retarded materials for outdoor applications

The current article deals with the development of different novel, tailor-made polyolefin formulations exhibiting both low flammability and high weathering resistance, so as to provide value-added polyethylene grades with extended service lifetime. Two low-density (LDPE) and one linear low-density (LLDPE) polyethylene grades were modified via melt compounding with an additive system comprising: (a) a nitrogen-phosphorous intumescent system for flame retardance and (b) a hindered amine light stabilizer and a benzophenone-type UV absorber for UV/heat stabilization, at a total loading of 30–35 wt%. The target was to reach V0 classification in UL94V flammability tests, while to a large extent maintaining the mechanical properties, such as, tensile and impact strength of the investigated polymers, thus ensuring that the additives do not interfere significantly with the material quality. Subsequently, the compounds were subjected to separate artificial UV and heat aging at 100°C for 1500 h; the formulations showed good flame retardance, even after prolonged artificial weathering, but there was an observable, although acceptable, decrease in the mechanical properties. Nevertheless, all the results show that the developed polyethylene compounds are very promising for outdoor applications, such as, irrigation piping and profiles, where long-term weathering stability is important, and where flame retardance is important for safety during storage.