Infrastructure dependent wireless multicast - the effect of spatial diversity and error correction

The use of multiple Access Points (APs) with one AP placed at the middle of a coverage area and the remaining placed at the edge may reduce the Packet Error Rate (PER) experienced by a group of multicast receivers. This paper shows that Spatial Diversity can augment the channel quality experienced especially by those nodes which are located farther from the Master AP, i.e. the AP at the middle, however this study also demonstrates the need for error correction scheme. The aim of this analysis is to propose a means of enhancing the infrastructure end of an IEEE 802.11n Wireless Local Area Network (WLAN), such that multicast data can be delivered reliably in order to guarantee that the received video has an adequate Peak Signal to Noise Ratio (PSNR), but with the constraint that the Medium Access Control (MAC) and the Physical (PHY) layer of the receivers are not modified, hence a legacy IEEE 802.11n node may join the multicast group and experience good Quality of Service.peer-reviewe

Managing engine thermal state to reduce friction losses during warm-up

The thermal behaviour of a 2.4 l direct injection diesel engine has been investigated to identify how the fuel consumption penalty associated with operation during warm–up can be minimised. A version of PROMETS (Programme for Modelling Engine Thermal Systems) was developed to support the investigations. The developments improved the representation of thermal-friction conditions in the oil circuit, extended the piston heat transfer sub-model to account for the effects of piston cooling jets and introduced a main bearing thermal-friction model to predict friction and oil film temperatures. Computational studies were complemented by an experimental investigation of the effectiveness of pre-heating the oil feed to the bearings. Results show that heat transfer from the oil film to the bearings shells and crankshaft journal reduces the benefit in friction savings. Other measures considered were exhaust gas heat recovery, repositioning of the oil main gallery within the block, thermal energy storage, reductions in engine thermal capacity and a novel split-EGR cooler able to cool the EGR gases and heat either the coolant or oil streams. All of the above measures were investigated in isolation, but where appropriate different measures were adopted in conjunction to achieve even greater fuel savings. During warm-up the energy available to raise fluid temperatures is small. As a result, over the New European Drive Cycle, thermal energy storage showed the greatest benefits. Given an available source of thermal energy which can be transferred to the oil over a chosen time, simulations indicate that a higher power input over a shorter period is most beneficial. This reflects the increased sensitivity of oil viscosity to temperature changes at colder temperatures which in turn means that the potential to reduce friction is highest in the first minutes after engine start up but drops rapidly hereafter. Results also show how the balance of energy transfers out of the oil changes as the engine warms up and point to the importance of oil interaction with components in the lower parts of the engine which have a large thermal capacity, such as elements supporting the main bearings, the crankshaft and the lower liner which limit the rate of temperature rise of the oil. A combination of supplementary heat introduction into the oil circuit from a thermal store and an elimination of heat losses from the oil to the lower parts of the engine resulted in a fuel consumption saving close to that achieved by starting the engine fully warm, which equates to around 6% improvement

Managing engine thermal state to reduce friction losses during warm-up

The thermal behaviour of a 2.4 l direct injection diesel engine has been investigated to identify how the fuel consumption penalty associated with operation during warm–up can be minimised. A version of PROMETS (Programme for Modelling Engine Thermal Systems) was developed to support the investigations. The developments improved the representation of thermal-friction conditions in the oil circuit, extended the piston heat transfer sub-model to account for the effects of piston cooling jets and introduced a main bearing thermal-friction model to predict friction and oil film temperatures. Computational studies were complemented by an experimental investigation of the effectiveness of pre-heating the oil feed to the bearings. Results show that heat transfer from the oil film to the bearings shells and crankshaft journal reduces the benefit in friction savings. Other measures considered were exhaust gas heat recovery, repositioning of the oil main gallery within the block, thermal energy storage, reductions in engine thermal capacity and a novel split-EGR cooler able to cool the EGR gases and heat either the coolant or oil streams. All of the above measures were investigated in isolation, but where appropriate different measures were adopted in conjunction to achieve even greater fuel savings. During warm-up the energy available to raise fluid temperatures is small. As a result, over the New European Drive Cycle, thermal energy storage showed the greatest benefits. Given an available source of thermal energy which can be transferred to the oil over a chosen time, simulations indicate that a higher power input over a shorter period is most beneficial. This reflects the increased sensitivity of oil viscosity to temperature changes at colder temperatures which in turn means that the potential to reduce friction is highest in the first minutes after engine start up but drops rapidly hereafter. Results also show how the balance of energy transfers out of the oil changes as the engine warms up and point to the importance of oil interaction with components in the lower parts of the engine which have a large thermal capacity, such as elements supporting the main bearings, the crankshaft and the lower liner which limit the rate of temperature rise of the oil. A combination of supplementary heat introduction into the oil circuit from a thermal store and an elimination of heat losses from the oil to the lower parts of the engine resulted in a fuel consumption saving close to that achieved by starting the engine fully warm, which equates to around 6% improvement

Robust wireless video multicast using distributed antennas-based IEEE 802.11n infrastructure

Wireless Video Multicast is prone to suffer from frequent packet losses, resulting from the fact that the IEEE 802.11 standard does not use any mechanisms such as Acknowledgements and retransmissions, to combat the errors that are common in the dynamic wireless medium. However this paper shows that the infrastructure can be adapted to reduce the wireless errors, by using spatial diversity and spatial expansion to combat the wireless medium's random nature. This is obtained by adding a number of antennas placed equidistantly at the edge of the coverage area, using the same total transmit power that would be used with one transmit antenna. Moreover, this paper shows that since the IEEE 802.11n, the standard which facilitates the use of multiple antennas, states that the maximum number of antennas at any transceiver is four, two Access Points can be used to transmit the same data packet in orthogonal time slots to transmit good quality H.264 video resulting in all nodes experiencing an average Peak Signal to Noise Ratio greater than 36dB for MCS-5 and MCS-6 for a coverage area having radius of 60m. Since only two time slots are used, these results are obtained with a ½ code rate which is an improvement to the code rate used in current cooperative schemes.peer-reviewe

The first identification of the uniqueness and authentication of Maltese extra virgin olive oil using 3D-fluorescence spectroscopy coupled with multi-way data analysis

The potential application of multivariate three-way data analysis techniques, namely parallel factor analysis (PARAFAC) and discriminant multi-way partial least squares regression (DN-PLSR), on three-dimensional excitation emission matrix (3D-EEM) fluorescent data were used to identify the uniqueness and authenticity of Maltese extra virgin olive oil (EVOO). A non-negativity constrained PARAFAC model revealed that a four-component model provided the most appropriate solution. Examination of the extracted components in mode 2 and 3 showed that these belonged to different fluorophores present in extra virgin olive oil. Application of linear discriminate analysis (LDA) and binary logistic regression analysis on the concentration of the four extracted fluorophores, showed that it is possible to discriminate Maltese EVOOs from non-Maltese EVOOs. The application of DN-PLSR provided superior means for discrimination of Maltese EVOOs. Further inspection of the extracted latent variables and their variable importance plots (VIPs) provided strong proof of the existence of four types of fluorophores present in EVOOs and their potential application for the discrimination of Maltese EVOOs.peer-reviewe

Association of autistic traits with depression from childhood to age 18 years

Importance Population-based studies following trajectories of depression in autism spectrum disorders (ASD) from childhood into early adulthood are rare. The role of genetic confounding and of potential environmental intermediaries, such as bullying, in any associations is unclear. Objectives To compare trajectories of depressive symptoms from ages 10 to 18 years for children with or without ASD and autistic traits, to assess associations between ASD and autistic traits and an International Statistical Classification of Diseases, 10th Revision (ICD-10) depression diagnosis at age 18 years, and to explore the importance of genetic confounding and bullying. Design, Setting, and Participants Longitudinal study of participants in the Avon Longitudinal Study of Parents and Children birth cohort in Bristol, United Kingdom, followed up through age 18 years. Data analysis was conducted from January to November 2017. Main Outcomes and Measures Depressive symptoms were assessed using the Short Mood and Feelings Questionnaire (SMFQ) at 6 time points between ages 10 and 18 years. An ICD-10 depression diagnosis at 18 years was established using the Clinical Interview Schedule–Revised. Exposures were ASD diagnosis and 4 dichotomized autistic traits (social communication, coherence, repetitive behavior, and sociability). An autism polygenic risk score was derived using the Psychiatric Genomics Consortium autism discovery genome-wide association study summary data. Bullying was assessed at ages 8, 10, and 13 years. Results The maximum sample with complete data was 6091 for the trajectory analysis (48.8% male) and 3168 for analysis of depression diagnosis at age 18 years (44.4% male). Children with ASD and autistic traits had higher average SMFQ depressive symptom scores than the general population at age 10 years (eg, for social communication 5.55 [95% CI, 5.16-5.95] vs 3.73 [95% CI, 3.61-3.85], for ASD 7.31 [95% CI, 6.22-8.40] vs 3.94 [95% CI, 3.83-4.05], remaining elevated in an upward trajectory until age 18 years (eg, for social communication 7.65 [95% CI, 6.92-8.37] vs 6.50 [95% CI, 6.29-6.71], for ASD 7.66 [95% CI, 5.96-9.35] vs 6.62 [95% CI, 6.43-6.81]). Social communication impairments were associated with depression at age 18 years (adjusted relative risk, 1.68; 95% CI, 1.05-2.70), and bullying explained a substantial proportion of this risk. There was no evidence of confounding by the autism polygenic risk score. Analysis in larger samples using multiple imputation led to similar but more precise results. Conclusions and Relevance Children with ASD and ASD traits have higher depressive symptom scores than the general population by age 10 years, which persist to age 18 years, particularly in the context of bullying. Social communication impairments are an important autistic trait in relation to depression. Bullying, as an environmental intermediary, could be a target for interventions

Totarol content and cytotoxicity varies significantly in different types of propolis

Propolis is a complex honeybee product deposited in the beehives, where it protects the hive and its occupants from microbial infection. Propolis has several reported medical applications in view of its numerous bioactive properties. The water insoluble fraction of crude Maltese honeybee propolis was extracted in methanol. Analysis by gas chromatography – mass spectrometry (GC-MS) showed the diterpenoid totarol to be the predominant constituent in all samples. The evaporated methanol residue was dissolved in dimethyl sulphoxide (DMSO) and used for cytotoxicity testing on human cancer cell lines using standard 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assays. Results obtained show that the propolis collected from Malta has cytotoxic activity in cancer cells in vitro. However, propolis collected from different sites, only a few miles apart and at different times of the year, showed marked variations in the cytotoxicity, which correlated clearly with totarol content. This reflects the differences in the species of plants, on which the bees had foraged and indicates the importance of collection site and season of collection on the bioactivity of propolis products.peer-reviewe

Centre d’anthropologie

Josiane Bru, ingénieur d’étudesPatricia Heiniger-Casteret, maître de conférences à l’Université de PauPhilippe Sahuc, maître de conférences à l’ENFA de Toulouse-Auzeville Thèmes et pratiques de la littérature orale La majorité des séances du séminaire de cette année a été consacrée à la légende, abordée sous différents aspects avant de revenir, en fin d’année, sur le conte et le travail du conteur. À partir d’une monographie des fêtes d’hiver de deux villages du Pays Basque, Thierry Truffaut ..

Centre d’anthropologie

Jean-Pierre Albert, directeur d’études avec Dominique Blanc, ingénieur d’études Approches anthropologiques du travail social Le séminaire a été construit, en alternance, autour, d’une part, d’apports théoriques et de débats concernant la pertinence d’un regard anthropologique et d’une recherche de type ethnographique dans l’analyse des « questions sociales » et des « interventions sur le social » et, d’autre part, de l’exposé de recherches en cours, telles que, cette année : les processus soc..