Haute école d'ingénierie et de gestion du canton de Vaud, HES-SO Haute Ecole Spécialisée de Suisse Occidentale

International audience

Seasonal and inter-annual climate variability have become important issues for farmers, and climate change has been shown to increase them. Simultaneously farmers and agricultural organizations are increasingly collecting observational data about in situ crop performance. Agriculture thus needs new tools to cope with changing environmental conditions and to take advantage of these data. Data mining techniques make it possible to extract embedded knowledge associated with farmer experiences from these large observational datasets in order to identify best practices for adapting to climate variability. We introduce new approaches through a case study on irrigated and rainfed rice in Colombia. Preexisting observational datasets of commercial harvest records were combined with in situ daily weather series. Using Conditional Inference Forest and clustering techniques, we assessed the relationships between climatic factors and crop yield variability at the local scale for specific cultivars and growth stages. The analysis showed clear relationships in the various location-cultivar combinations, with climatic factors explaining 6 to 46% of spatiotemporal variability in yield, and with crop responses to weather being non-linear and cultivar-specific. Climatic factors affected cultivars differently during each stage of development. For instance, one cultivar was affected by high nighttime temperatures in the reproductive stage but responded positively to accumulated solar radiation during the ripening stage. Another was affected by high nighttime temperatures during both the vegetative and reproductive stages. Clustering of the weather patterns corresponding to individual cropping events revealed different groups of weather patterns for irrigated and rainfed systems with contrasting yield levels. Best-suited cultivars were identified for some weather patterns, making weather-site-specific recommendations possible. This study illustrates the potential of data mining for adding value to existing observational data in agriculture by allowing embedded knowledge to be quickly leveraged. It generates site-specific information on cultivar response to climatic factors and supports on-farm management decisions for adaptation to climate variability.

Un certain nombre de travaux ont montré l’intérêt des espaces de discussion dans la prévention des risques psychosociaux. Cependant, il n’existe pas à ce jour de validation empirique quantitative de leurs effets et de leurs antécédents. Cet article propose tout d’abord un outil de mesure de la présence des EDD et de leur qualité. Il montre les effets des EDD sur la limitation de l’épuisement professionnel et met l’accent sur les conditions managériales permettant l’émergence et le bon fonctionnement des EDD dans une organisation. L’analyse empirique s’appuie sur une enquête quantitative auprès de 1 373 agents, menée en 2015 dans une collectivité territoriale.

Osteoporosis is a metabolic bone disorder characterized by low bone mass, degradation of bone microarchitecture, and susceptibility to fracture. It is a growing major health concern across the world, especially in the elderly population. Osteoporosis can cause hip or spinal fractures that may lead to high morbidity and socio-economic burden. Therefore, there is a need for early diagnosis of osteoporosis and prediction of fragility fracture risk. In this review, state of the art and recent advances in imaging techniques for diagnosis of osteoporosis and fracture risk assessment have been explored. Segmentation methods used to segment the regions of interest and texture analysis methods used for classification of healthy and osteoporotic subjects are also presented. Furthermore, challenges posed by the current diagnostic tools have been studied and feasible solutions to circumvent the limitations are discussed. Early diagnosis of osteoporosis and prediction of fracture risk require the development of highly precise and accurate low-cost diagnostic techniques that would help the elderly population in low economies.

While recent efforts to catalogue Earth’s microbial diversity have focused upon surface and marine habitats, 12–20 % of Earth’s biomass is suggested to exist in the terrestrial deep subsurface, compared to ~1.8 % in the deep subseafloor. Metagenomic studies of the terrestrial deep subsurface have yielded a trove of divergent and functionally important microbiomes from a range of localities. However, a wider perspective of microbial diversity and its relationship to environmental conditions within the terrestrial deep subsurface is still required. Our meta-analysis reveals that terrestrial deep subsurface microbiota are dominated by Betaproteobacteria, Gammaproteobacteria and Firmicutes , probably as a function of the diverse metabolic strategies of these taxa. Evidence was also found for a common small consortium of prevalent Betaproteobacteria and Gammaproteobacteria operational taxonomic units across the localities. This implies a core terrestrial deep subsurface community, irrespective of aquifer lithology, depth and other variables, that may play an important role in colonizing and sustaining microbial habitats in the deep terrestrial subsurface. An in silico contamination-aware approach to analysing this dataset underscores the importance of downstream methods for assuring that robust conclusions can be reached from deep subsurface-derived sequencing data. Understanding the global panorama of microbial diversity and ecological dynamics in the deep terrestrial subsurface provides a first step towards understanding the role of microbes in global subsurface element and nutrient cycling.

A platform to study ultrasound as a source for wireless energy transfer and communication for implanted medical devices is described. A tank is used as a container for a pair of electroacoustic transducers, where a control unit is fixed to one wall of the tank and a transponder can be manually moved in three axes and rotate using a mechanical system. The tank is filled with water to allow acoustic energy and data transfer, and the system is optimized to avoid parasitic effects due to cables, reflection paths and cross talk problems. A printed circuit board is developed to test energy scavenging such that enough acoustic intensity is generated by the control unit to recharge a battery loaded to the transponder. In the same manner, a second printed circuit board is fabricated to study transmission of information through acoustic waves.

Herbivorous arthropods, such as spider mites, are one of the major causes of annual crop losses. They are usually hard to spot before a severe infestation takes place. When feeding, these insects cause external perturbation that triggers changes in the underlying physiological process of a plant, which are expressed by a generation of distinct variations of electrical potential. Therefore, plant electrophysiology data portray information of the plant state. Analyses involving machine learning techniques applied to plant electrical response triggered by spider mite infestation have not been previously reported. This study investigates plant electrophysiological signals recorded from 12 commercial tomatoes plants contaminated with spider mites and proposes a workflow based on Gradient Boosted Tree algorithm for an automated differentiation of the plant’s normal state from the stressed state caused by infestation. The classification model built using the signal samples recorded during daylight and employing a reduced feature subset performs with an accuracy of 80% in identifying the plant’s stressed state. Furthermore, the Hjorth complexity encloses the most relevant information for discrimination of the plant status. The obtained findings open novel access towards automated detection of insect infestation in greenhouse crops and, consequently, more optimal prevention and treatment approaches.

Abstract Covid-19 mitigation commonly involves social distancing. Due to its high economic toll and its impact on personal freedom, we need to ease social distancing and deploy alternative measures, while preventing a second wave of infections. Bluetooth app-based contact tracing has been proposed, focusing on symptomatic cases and isolating their contacts. However, this approach would miss many transmissions by asymptomatic cases. To improve effectiveness of app-based mitigation, we propose to complement contact tracing with Smart Testing relying on Contact Counting (STeCC). STeCC focuses virus RNA testing to people with exceptionally high numbers of contacts. These people are at particularly high risk to become infected (with or without symptoms) and transmit the virus. Mathematical modeling shows that a mitigation strategy combining STeCC and contact tracing in one app will be more efficient than contact tracing and works when ≈50% (instead of ≥60%) of the total population participate. Similarly, it requires 50-100 fold less tests than randomized virus testing alone. These gains in efficiency may be critical for success. STeCC could be integrated in the current Bluetooth tracing apps. Thus, STeCC is technically feasible and can reduce the pandemic’s reproduction number by 2.4-fold (e.g. from R 0 =2.4 to R eff =1) with realistic test numbers (≈166 per 100’000 people per day), when a realistic fraction of the population would use the app (i.e. ≈50% in total population). Thereby, STeCC efficiently complements the portfolio of mitigation strategies, which allow easing social distancing without compromising public health.

Les organisations publiques contemporaines subissent aujourd’hui de nombreuses transformations, parfois lourdes de conséquences pour les agents publics. Le contrat psychologique (modélisation de la relation d’emploi) qui lie l’agent à son organisation en est bousculé. Cet article se propose d’examiner les processus en jeu afin de comprendre ces changements tout en préservant la santé des agents. Il ambitionne d’apporter des éléments de compréhension du lien existant entre rupture, violation du contrat psychologique et mal-être au travail dans le contexte des organisations publiques. Cette recherche-intervention examine ainsi les processus par lesquels la rupture du contrat psychologique débouche sur du mal-être, en lien avec des atteintes aux ressources. Cette analyse est réalisée dans le contexte d’un service public en direction des personnes âgées et des personnes handicapées ayant fait l’objet d’une recherche-intervention d’une durée d’une année complète. Ce contexte (les métiers du social) nous permet d’interroger à la fois un contrat psychologique tourné vers le service au public et des contraintes classiques comme l’augmentation de la charge de travail ou la raréfaction des moyens. Nos résultats montrent l’importance du collectif dans le processus de reconstruction des ressources mais également que la violation du contrat psychologique correspond à une atteinte à des ressources fondamentales qui constituent le cœur de ce contrat. La démarche de cette recherche révèle la pertinence de la méthodologie de recherche-intervention dans le développement de connaissances dans le domaine de la santé au travail.

The improvement of thermal energy use in batch and semi-continuous processes utilizing established techniques such as Pinch Analysis faces challenges as direct heat recovery is restricted and schedule dependent, limiting broad industrial application. In overcoming this limitation, sensible heat storage integration has proven to be effective in achieving significant and less schedule-sensitive heat recovery but designing solutions is problematic given the complex trade-offs that occur. The presented graphical design method relies on the Indirect Sources Sinks Profiles (ISSPs) which extends the scope of time-average models and brings a systematic foundation to the design procedure. Graphical assignment zones are introduced to represent on the ISSPs constraints and degrees of freedom that apply when designing the Heat Exchanger and Storage Network (HESN) that can achieve the target heat recovery, given by ISSP overlap. A general procedure for their determination is presented, alongside resulting HESN designs for a case study process which achieve utility reductions of 35.0% up to 76.0%. Designs are automatically balanced making them functional concepts without manual adjustment, and although not cost-optimized, are inherently reduced in complexity by the method and suitable for further stepwise improvement.

A novel concept of Oxygen Saturation (SpO2) sensor embedded in a finger ring is presented in this paper. Due to the mechanical conception of the probe, the sensor fits any finger topology and assures a constant force applied to the phalanx. Ambient light artifacts are rejected at the analog electronics level. Finally, an innovative distribution of light sources and detectors and a dedicated signal processing procedure resolve the anatomical heterogeneity of different phalanx topologies, compensate low perfusion indexes due to the phalanx anatomy and estimates equivalent pulse oximetry SpO2 indexes. First in-vivo validation results of the novel sensor are discussed at the end of the paper.

The adoption of technology in urban participatory planning with tools such as Virtual Geographic Environments (VGE) promises a broader engagement of urban dwellers, which should ultimately lead to the creation of better cities. However, the authorities and urban experts show hesitancy in endorsing these tools in their practices. Indeed, several parameters must be wisely considered in the design of VGE; if misjudged, their impact could be damaging for the participatory approach and the related urban project. The objective of this study is to engage participants (N = 107) with common tasks conducted in participatory sessions, in order to evaluate the users’ performance when manipulating a VGE. We aimed at assessing three crucial parameters: (1) the VGE representation, (2) the participants’ idiosyncrasies, and (3) the nature of the VGE format. The results demonstrate that the parameters did not affect the same aspect of users’ performance in terms of time, inputs, and correctness. The VGE representation impacts only the time needed to fulfill a task. The participants’ idiosyncrasies, namely age, gender and frequency of 3D use also induce an alteration in time, but spatial abilities seem to impact all characteristics of users’ performance, including correctness. Lastly, the nature of the VGE format significantly alters the time and correctness of users interactions. The results of this study highlight concerns about the inadequacies of the current VGE practices in participatory sessions. Moreover, we suggest guidelines to improve the design of VGE, which could enhance urban participatory planning processes, in order to create better cities.

This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors' survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures.

More than 60 years ago, Prof. S. Rusck introduced a coupling model to take into account the interaction of lightning-generated electromagnetic fields with overhead power transmission and distribution lines. The model which assumes that the ground is perfectly conducting has served the power system research community for many decades. Recently, it was found that this model is not complete because some of the forcing terms in the relevant transmission line equations, which are based purely on the scalar and vector potentials, were missing. In the present paper, the correct transmission line equations pertinent to the interaction of external electromagnetic fields with overhead lines, described in terms of scalar and vector potentials, are derived by incorporating the effects of a finitely conducting ground. The model presented in this paper can be considered as a correction and an extension of the Rusck model to account for a finitely conducting ground.

In this article, we present a machine learning-based method to locate lightning flashes using calculations of lightning-induced voltages on a transmission line. The proposed approach takes advantage of the preinstalled voltage measurement systems on power transmission lines to get the data. Hence, it does not require the installation of additional sensors such as extremely low frequency, very low frequency, or very high frequency. The proposed model is shown to yield reasonable accuracy in estimating two-dimensional geolocations for lightning strike points for different grid sizes up to 100 × 100 km <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The algorithm is shown to be robust against the distance between the voltage sensors, lightning peak current, lightning current rise time, and signal to noise ratio of the input signals.

Abstract Research into the use of BELF, notably through the analysis of authentic data from business contexts, has shown that BELF communication is intrinsically intercultural, with BELF being used in a wide range of settings and with diverse constellations of interlocutors. Yet, whilst business English teaching materials take a range of approaches to culture, they often fail to address the complexity of intercultural communication or integrate it sufficiently in the overall curriculum. In this paper, findings from BELF research on oral interaction in the workplace are considered from the point of view of pragmatics and in relation to the interface between culture and language. It is proposed that by adopting a research-based approach to curriculum design, syllabus and course development, which addresses not only intercultural communication within the overall concept of communicative competence, but also learning theory and teaching methodology, awareness of intercultural aspects of communication can both be raised in a more systematic manner and also applied in the classroom. This should help those entering the jobs' market to better meet the needs of today's employers and globalised markets. Finally, practical suggestions are given for possible approaches to the teaching of intercultural communication within the context of business English training and, above all, in the light of BELF research findings. The need for change in teacher education is also considered.

Biomass for energy production has been extensively studied in the recent years. To overcome some constraints imposed by the chemical–physical properties of the biomass, several pretreatments have been proposed. Torrefaction is one of the most interesting pretreatments because torrefied biomass holds a wide range of advantages over raw biomass. The devolatilization of water and some oxygenated compounds influences the increase in the calorific value on both a mass and volumetric basis. The increase in the density reduces the transportation costs. Moreover, the decreased moisture content increases the resistance of biomass to biological degradation, thus facilitating its storage for long periods. Under torrefaction conditions, approximately 10–40 wt % of the initial biomass is converted into volatile matter, including liquid and non-condensable combustible gases. The energy efficiency of the process could greatly benefit the exploitation of the energy content of these products. Recent studies and technological solutions have demonstrated the possibility to realize polygeneration systems that integrate torrefaction/pyrolysis to a combustion process with the aim of obtaining torrefied material/biochar and/or energy from biomass. Some examples include Pyreg, Pyreg-Aactor GT, TorPlant, and Top Process. The identification of the main volatiles produced under the torrefaction regime is useful for the optimization of the operating conditions of the integrated system. The integrated process raises some concerns when biomass from phytoremediation and wood from demolition and construction activities are used as feedstock because they could contain potential toxic elements (PTEs). During the torrefaction treatment, the fate of PTEs should be controlled to avoid their release in the gas phase and to evaluate the extent of their concentration in the torrefied biomass. The present work aims at studying torrefaction as an eco-sustainable process for the combined production of a solid biofuel with improved characteristics with respect to the starting material and a combustible vapor phase, embedded in the gas carrier flow, to be directly burned for energy recovery. Herein, torrefaction tests on Populus nigra L. branches from phytoremediation and demolition wood were conducted at three temperatures, 250, 270, and 300 °C, at a holding time of 15 min. The energetic content of torrefied materials was determined. At the same time, the fate of the heavy metals (Cd, Pb, and Zn) in the raw biomass at different torrefaction temperatures was studied, and their mobility in the torrefied biomass was investigated and compared to the mobility in the raw biomass.

The paper proposes an analytical homogenization procedure to predict the overall elastic properties of shot-earth, a sustainable composite material made of excavated soil, aggregates and, if needed, a binder for stabilization. A multi-step methodology based on the Mori-Tanaka approach is used to account for the stabilized soil inclusions. This approach is proposed in order to shorten the mix-design procedures and readily provide to the structural engineers a set of mechanical properties of the shot-earth components to be used in the early design phases, when the construction field is not open yet and excavation of the site has not begun. The analytical results were successfully validated through an experimental campaign.

The article provides analytical expressions for the electromagnetic fields generated by a lightning return stroke characterized by a channel-base current with arbitrary time waveform, in presence of either a perfectly conducting or a lossy ground, assuming the transmission line model for the current along the channel. In this second case, a time-domain analytical expression for the Cooray-Rubinstein formula is presented. The main idea that leads to the derivation of analytical formulas consists of dividing the channel into intervals in which the distance between the field source point and the observation point can be approximated with a linear function of the time, and of the spatial coordinates of both points. In the companion aticle, a detailed comparison is proposed with the classical (numerical) approach highlighting an excellent agreement both at close and far distances, considering all the values of practical interest for the ground conductivity. Moreover, the method guarantees a meaningful improvement in computational performance.

In the domain of electric traction, the demand for medium voltage supply systems of high power, compact size and reduced weight is growing. Thanks to the new semiconductors (HV-IGBT, IGCT) with high voltage capability, the multilevel topologies with medium frequency transformer become very attractive. Several solutions based on this principle were proposed these last years. A 10 kVA, four stages multilevel converter is presented. This solution seems particularly well adapted to the different requirements (volume, weight, EMC, loss) of the electric traction domain