86 research outputs found

    First Steps in the Cross-Comparison of Solar Resource Spatial Products in Europe

    No full text
    International audienceYearly sum of global irradiation is compared from six spatial (map) databases: ESRA, PVGIS, Meteonorm, Satel-Light, HelioClim-2, and NASA SSE. This study does not identify the best database, but in a relative cross-comparison it points out to the areas of higher variability of outputs. Two maps are calculated to show an average of the yearly irradiation for horizontal surface together with the standard deviation that illustrates the combined effect of differences between the databases at the regional level. Differences at the local level are analysed on a set of 37 randomly selected points: global irradiation is calculated from subset of databases for southwards inclined (at 34°) and 2-axis tracking surfaces. Differences at the regional level indicate that within 90% of the study area the uncertainty of yearly global irradiation estimates (expressed by standard deviation) does not exceed 7% for horizontal surface, 8.3% for surface inclined at 34°, and 10% for 2-axis tracking surface. Higher differences in the outputs from the studied databases are found in complex climate conditions of mountains, along some coastal zones and in areas where solar radiation modelling cannot rely on sufficient density and quality of input dat

    Dynamics of Non-visual Responses in Humans: As Fast as Lightning?

    Get PDF
    The eye drives non-visual (NV) responses to light, including circadian resetting, pupillary reflex and alerting effects. Initially thought to depend on melanopsin-expressing retinal ganglion cells (ipRGCs), classical photopigments play a modulatory role in some of these responses. As most studies have investigated only a limited number of NV functions, generally under conditions of relatively high light levels and long duration of exposure, whether NV functions share similar irradiance sensitivities and response dynamics during light exposure is unknown. We addressed this issue using light exposure paradigms spectrally and spatially tuned to target mainly cones or ipRGCs, and by measuring longitudinally (50 min) several NV responses in 28 men. We demonstrate that the response dynamics of NV functions are faster than previously thought. We find that the brain, the heart, and thermoregulation are activated within 1 to 5 min of light exposure. Further, we show that NV functions do not share the same response sensitivities. While the half-maximum response is only ∼48 s for the tonic pupil diameter, it is ∼12 min for EEG gamma activity. Most NV responses seem to be saturated by low light levels, as low as 90 melanopic lux. Our results also reveal that it is possible to maintain optimal visual performance while modulating NV responses. Our findings have real-life implications. On one hand, light therapy paradigms should be re-evaluated with lower intensities and shorter durations, with the potential of improving patients’ compliance. On the other hand, the significant impact of low intensity and short duration light exposures on NV physiology should make us reconsider the potential health consequences of light exposure before bedtime, in particular on sleep and circadian physiology

    Experimental validation of daylighting simulation methods for complex fenestration systems

    Get PDF
    The objective of this paper is to assess the capability of existing lighting simulation methods to predict the performance of complex fenestration systems, which are becoming a commonly used component in buildings construction domain. A specific experimental protocol was conducted to collect reliable reference data based on illuminance measurements inside a black box with (and without) one complex glazing sample facing a measured external luminance distribution. Two types of simulation methods were tested and compared: The first is based on modeling the glazing sample in a ray-tracing simulation program and the second is based on use of the samples' BTDF data. The BTDF data sets were combined with the external luminance distribution to predict the flux distribution inside the room and the resulting illuminance values at the reference points. The comparison between the experimental reference data and the simulation results showed that the influence of the CFS could be predicted with good accuracy

    The project ENDORSE: exploiting EO data to develop pre-market services in renewable energy

    No full text
    International audienceThe ENDORSE project is co-funded by the FP7 programme of the European Commission, from 2011 to 2013. It exploits the atmosphere service MACC of the European GMES programme (Global Monitoring for Environment and Security) together with other Earth Observation (EO) data and modelling. It aims at providing public authorities and private investors with accurate evaluation and forecasts of renewable resources. The focus is on the devel-opment of downstream services that create added-value information. We present here the achievements of the first period. A very accurate though fast algorithm describing the position of the sun in the sky has been developed. A series of recommendations for quality control of meteorological data have been issued. All algorithms are available as code sources and are being implemented as Web processing services (WPS). Support vector machine techniques prove successful to map the air temperature at 2-m height from satellite images and a few measurements at ground level. The next development of ENDORSE is a portfolio of pre-market downstream services, serving as precursors and examples of best practices for similar services. The resulting services will be described using the INSPIRE metadata and declared in an existing Catalog Service for the Web (CSW) dedicated to energy. Finally, we discuss the mutual benefits between GEOSS (Global Earth Observation System of Systems) and ENDORSE

    Exploitation of distributed solar radiation databases through a smart network: the project SoDa

    No full text
    The project SoDa answers the needs of industry and research for information on solar radiation parameters with a satisfactory quality. The methodology is user-driven with a large involvement of users in the project, who will gauge the progresses and achievements. A prototype service will be developed, using Internet technology, that will integrate and efficiently exploit diverse networked information sources to supply value-added information. A multi-disciplinary consortium has been assembled, which gathers companies and researchers with the necessary expertise in solar radiation and information and communication technologies. Customers and potential users are also represented as partners in the consortium via the involvement of commercial private vendors of solar radiation databases and of representatives of large research and development programs. A call is launched to recruit customers to assess the prototype. The project SoDa builds on the expertise gained in previous projects, such as the digital atlases MeteoNorm and European Solar Radiation Atlas, the Web servers Satel-Light and Helioserve, and the Guide of the Chartered Institute of Building Services Engineers of United Kingdom. Access to data and applications will be improved; efforts will be made on interpolation methods and satellite data processing to achieve better quality; emphasis will be put on applications to supply information actually needed by customers, instead of raw data

    Comfort-Oriented Metamorphic House (COMETAE)

    Get PDF
    Publications Internes de l'IRISA ISSN : 2102-6327This proposal aims at challenging the existing design paradigm of residential building architecture with insights from pervasive computing, robotics, human-computer interaction and cognitive ergonomics. ICT and architecture will be holistically integrated in order to realize a radical advancement leading to metamorphic houses. Supported by ICT, domestic environments will self-adapt to the ongoing activities of inhabitants, to increase the comfort of living and optimize the use of space and energy. The same physical space will be transformed for diff erent uses, giving inhabitants the illusion of living in a bigger, more adapted and more comfortable place. The traditional tradeoff between comfort and energy conservation will also be revisited, thanks to an optimal exploitation of natural light, heat and ventilation. The realization of the targeted breakthrough will be achieved through cross-fertilization between involved disciplines and by the support of a panel of final users, architects and building engineers in the design, development and evaluation phases. COMETAE will introduce a novel approach to smart spaces research, where the space is itself an actuator of the system. Indoor environment, space and energy use will be optimized with respect to environmental factors, occupants' activities and life cycle, by orchestrating adaptive robotic building components, while ensuring occupants' safety. New coupling between inhabitants and their environment will be enabled by combining human-computer interaction and space recon guration, considering beauty of interaction and multi-user scenarios. This proposal opens the way towards a radically new use of ICT, needed to address future limitations of space and energy in the domestic environment, imposed by the ongoing and future evolutions of technology, environmental questions and socio-demographic factors

    MESoR - Management and exploitation of solar resource knowledge

    No full text
    CD-ROMKnowledge of the solar resource is essential for the planning and operation of solar energy systems. A number of data bases giving information on solar resources have been developed over the past years. The result is a fragmentation of services each having each own mechanism of access and all are giving different results due to different methods, input data and base years. The project MESoR, co-funded by the European Commission, reduces the associated uncertainty by setting up standard benchmarking rules and measures for comparing the data bases, user guidance to the application of resource data and unifying access to various data bases

    SoDa: a Web service on solar radiation

    No full text
    ISBN 3-9809656-4-3International audienceA Web service has been developed for answering the needs of industry and research for information on solar radiation parameters with a satisfactory quality. It intends to solve the three major problems identified by customers: i) improving access to information, ii) improving knowledge on space and time structure and iii) improving matching of delivered information to actual needs of customers. This service (http://www.soda-is.com) is also innovative with respect to the Internet technologies: it is performing a smart networking of information sources of different natures: databases (radiation, meteorology, elevation, geography...) and algorithms (computation of radiation on slopes, sizing of systems...). These sources were available separately and are geographically dispersed. The service SoDa makes them cooperating and combines them in order to answer to requests, ranging from a series of irradiation values to the sizing of a system

    Abdominal Surgery in Patients With Idiopathic Noncirrhotic Portal Hypertension: A Multicenter Retrospective Study

    Get PDF
    In patients with idiopathic noncirrhotic portal hypertension (INCPH), data on morbidity and mortality of abdominal surgery are scarce. We retrospectively analyzed the charts of patients with INCPH undergoing abdominal surgery within the Vascular Liver Disease Interest Group network. Forty‐four patients with biopsy‐proven INCPH were included. Twenty‐five (57%) patients had one or more extrahepatic conditions related to INCPH, and 16 (36%) had a history of ascites. Forty‐five procedures were performed, including 30 that were minor and 15 major. Nine (20%) patients had one or more Dindo‐Clavien grade ≥ 3 complication within 1 month after surgery. Sixteen (33%) patients had one or more portal hypertension–related complication within 3 months after surgery. Extrahepatic conditions related to INCPH (P = 0.03) and history of ascites (P = 0.02) were associated with portal hypertension–related complications within 3 months after surgery. Splenectomy was associated with development of portal vein thrombosis after surgery (P = 0.01). Four (9%) patients died within 6 months after surgery. Six‐month cumulative risk of death was higher in patients with serum creatinine ≥ 100 μmol/L at surgery (33% versus 0%, P < 0.001). An unfavorable outcome (i.e., either liver or surgical complication or death) occurred in 22 (50%) patients and was associated with the presence of extrahepatic conditions related to INCPH, history of ascites, and serum creatinine ≥ 100 μmol/L: 5% of the patients with none of these features had an unfavorable outcome versus 32% and 64% when one or two or more features were present, respectively. Portal decompression procedures prior to surgery (n = 10) were not associated with postoperative outcome. Conclusion: Patients with INCPH are at high risk of major surgical and portal hypertension–related complications when they harbor extrahepatic conditions related to INCPH, history of ascites, or increased serum creatinine

    Early liver transplantation for severe alcohol-related hepatitis not responding to medical treatment: a prospective controlled study

    Full text link
    peer reviewedBackground: Early liver transplantation for severe alcohol-related hepatitis is an emerging treatment option. We aimed to assess the risk of alcohol relapse 2 years after early liver transplantation for alcohol-related hepatitis compared with liver transplantation for alcohol-related cirrhosis after at least 6 months of abstinence. Methods: We conducted a multicentre, non-randomised, non-inferiority, controlled study in 19 French and Belgian hospitals. All participants were aged 18 years or older. There were three groups of patients recruited prospectively: patients with severe alcohol-related hepatitis who did not respond to medical treatment and were eligible for early liver transplantation according to a new selection scoring system based on social and addiction items that can be quantified in points (early transplantation group); patients with alcohol-related cirrhosis listed for liver transplantation after at least 6 months of abstinence (standard transplantation group); patients with severe alcohol-related hepatitis not responding to medical treatment not eligible for early liver transplantation according to the selection score (not eligible for early transplantation group), this group did not enter any further liver transplantation processes. We also defined a historical control group of patients with severe alcohol-related hepatitis unresponsive to medical therapy and non-transplanted. The primary outcome was the non-inferiority of 2-year rate of alcohol relapse after transplantation in the early transplantation group compared with the standard transplantation group using the alcohol timeline follow back (TLFB) method and a prespecified non-inferiority margin of 10%. Secondary outcomes were the pattern of alcohol relapse, 2-year survival rate post-transplant in the early transplantation group compared with the standard transplantation group, and 2-year overall survival in the early transplantation group compared with patients in the not eligible for early transplantation group and historical controls. This trial is registered with ClinicalTrials.gov, NCT01756794. Findings: Between Dec 5, 2012, and June 30, 2016, we included 149 patients with severe alcohol-related hepatitis: 102 in the early transplantation group and 47 in the not eligible for early transplantation group. 129 patients were included in the standard transplantation group. 68 patients in the early transplantation group and 93 patients in the standard transplantation group received a liver transplant. 23 (34%) patients relapsed in the early transplantation group, and 23 (25%) patients relapsed in the standard transplantation group; therefore, the non-inferiority of early transplantation versus standard transplantation was not demonstrated (absolute difference 9·1% [95% CI –∞ to 21·1]; p=0·45). The 2-year rate of high alcohol intake was greater in the early transplantation group than the standard transplantation group (absolute difference 16·7% [95% CI 5·8–27·6]) The time spent drinking alcohol was not different between the two groups (standardised difference 0·24 [95% CI −0·07 to 0·55]), but the time spent drinking a large quantity of alcohol was higher in the early transplantation group than the standard transplantation group (standardised difference 0·50 [95% CI 0·17–0·82]). 2-year post-transplant survival was similar between the early transplantation group and the standard transplantation group (hazard ratio [HR] 0·87 [95% CI 0·33–2·26]); 2-year overall survival was higher in the early transplantation group than the not eligible for early transplantation group and historical controls (HR 0·27 [95% CI 0·16–0·47] and 0·21 [0·13–0·32]). Interpretation: We cannot conclude non-inferiority in terms of rate of alcohol relapse post-transplant between early liver transplantation and standard transplantation. High alcohol intake is more frequent after early liver transplantation. This prospective controlled study confirms the important survival benefit related to early liver transplantation for severe alcohol-related hepatitis; and this study provides objective data on survival and alcohol relapse to tailor the management of patients with severe alcohol-related hepatitis. Funding: The present study has been granted by the French Ministry of Health—Programme Hospitalier de Recherche Clinique 2010
    corecore