An Examination of High School Intra-District Funding in Two Virginia School Divisions

Most states allocate education funds by grant or category at the district level, and most districts distribute funds at the school level. 1 Differences between allocations from the states to the districts and distribution methods from the districts to the schools can lead to unintended consequences in funding equity. This may undermine the purpose of the funding policies developed by state legislatures. Most states use a formula that provides a foundation funding amount to the district for each student. In addition, most states typically provide supplementary categorical funding to the district based on demographic characteristics of students (such as free and reduced lunch eligibility, English language learner, etc.), which, theoretically, increases the level of services needed and, therefore, the cost of educating those students.2 The distribution of these categorical funds and tracking of money occur only at the district level, so no evidence exists to show that money is reaching the schools or students who need it most. This analysis explores intra-district spending and resource distribution within two school divisions in Virginia to determine what, if any, inequities exist. The researcher adapted Berne and Stiefel\u27s (1984) inter-district framework in which three equity concepts were examined: horizontal equity, vertical equity, and equal opportunity. Once the researcher obtained the financial and descriptive information about the two divisions and the high schools within those divisions, the researcher further examined the schools with the highest and the lowest percentage of students living in poverty (indexed by participation in the federal free and reduced-price lunch program). The study found that while average class size varies to some extent among the schools, there are important differences in teacher quality, curriculum, equipment, and supplies. Even though this study was limited in its sample size, the implications, and the opportunities are far reaching. If low-SES children have the proper support and understanding, financial status does not have to be the ultimate determinant of academic achievement

Experimental phase-space-based optical amplification of scar modes

Waves billiard which are chaotic in the geometrical limit are known to support non-generic spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in micro-cavity lasers and vertically-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in their wave analogous phase space representation, we report experimental results of scar modes selection by gain in a doped D-shaped optical fiber

Validation of three satellite-derived databases of surface solar radiation using measurements performed at 42 stations in Brazil

International audienceThe SoDa website (www.soda-pro.com) is populated with numerous solar-related Web services. Among them, three satellite-derived irradiation databases can be manually or automatically accessed to retrieve radiation values within the geographical coverage of the Meteosat Second Generation (MSG) satellite: the two most advanced versions of the HelioClim-3 database (versions 4 and 5, respectively HC3v4 and HC3v5), and the CAMS radiation service. So far, these databases have been validated against measurements of several stations in Europe and North Africa only. As the quality of such databases depends on the geographical regions and the climates, this paper extends this validation campaign and proposes an extensive comparison on Brazil and global irradiation received on a horizontal surface. Eleven stations from the Brazilian Institute of Space Research (INPE) network offer 1 min observations, and thirty-one stations from the Instituto Nacional de Meteorologia (INMET) network offer hourly observations. The satellite-derived estimates have been compared to the corresponding observations on hourly, daily and monthly basis. The bias relative to the mean of the measurements for HC3v5 is mostly comprised between 1 and 3 %, and that for HC3v4 between 2 and 5 %. These are very satisfactory results and they demonstrate that HC3v5, and to a lesser extent HC3v4, may be used in studies of long-term changes in SSI in Brazil. The situation is not so good with CAMS radiation service for which the relative bias is mostly comprised between 5 and 10 %. For hourly irradiation, the relative RMSE ranges from 15 to 33 %. The correlation coefficient is very large for all stations and the three databases, with an average of 0.96. The three databases reproduce well the hour from hour changes in SSI. The errors show a tendency to increase with the viewing angle of the MSG satellite. They are greater in tropical areas where the relative humidity in the atmosphere is important. It is concluded that except for the overestimation by CAMS radiation service, the three databases are suitable for studies of the solar resources in Brazil

The Solar Forecast Similarity Method: a new method to compute solar radiation forecasts for the next day

International audienceThe need for PV plant owners to plan what they are injecting in the electricity grid is more and more stringent to avoid endangering the whole supply in electricity. A new solar forecast algorithm, named Solar Forecast Similarity Method, has been developed to predict irradiance for the next day based on a statistical study of the long term HelioClim-3 irradiation database. This algorithm searches in the past for the most similar days compared to the day of interest and uses their following days to produce a forecast. The model has been optimized against the database itself to compute the most adequate set of parameters over France and for the month of January 2014. With this configuration, the results are a null bias and a root mean square error of 48%. The algorithm outperforms the persistence by 20% and the error is similar to existing methods. An objective validation has then been carried out to compare the irradiance forecasts to high quality measurements from several Baseline Surface Radiation Network (BSRN) ground stations. The method is very promising since the comparison results are in line or lower than the one obtained with the first validation analysis performed on the HelioClim-3 database. For high frequencies, however, predictions have a high error for rapidly varying weather. This demonstrates that the method provides information for the averaged production the following day but requires another input to reliably predict high frequency irradiance

Validation of HelioClim-3 version 4, HelioClim-3 version 5 and MACC-RAD using 14 BSRN stations

International audienceThis communication presents the results of a comparison of three satellite-derived databases covering Africa, Europe, Middle East and part of South America, against corresponding 15 min irradiations of very high quality measured by fourteen Baseline Surface Radiation Network (BSRN) stations. The three databases are accessible via the SoDa Service website, and are the two latest versions of HelioClim-3: versions 4 (HC3v4) and 5 (HC3v5), and the MACC-RAD database. The comparison was performed for durations of 15 min, 1 h, 1 day and 1 month for both the global irradiation received on a horizontal surface (GHI) and the direct irradiation received on a plane normal to sun rays (DNI). It is found that the three satellite-derived radiation databases exhibit satisfactory performances. For most of the fourteen locations, HC3v5 surpasses HC3v4 and MACC-RAD, with a bias ranging from-4 to 5% for the GHI and for all tested duration. The correlation coefficient is large for all databases and most often greater than 0.92 for 15 min and 0.98 for daily irradiation for GHI. The RMSE is fairly constant for all locations for 15 min and is approximately 20 kWh m-2 –slightly greater for MACC-RAD.-For daily irradiation, it ranges between 300 and 400 kWh m-2 for HC3v5, 300 and 500 kWh m-2 for HC3v4, and 400 and 550 kWh m-2 for MACC-RAD. Bias for the DNI is larger in absolute values than for GHI for all databases:-12 to 10% for HC3v5. The correlation coefficient is most often greater than 0.68 for 15 min and 0.84 for daily irradiation. The RMSE for 15 min ranges between 46 and 60 kWh m-2 for HC3v5, 46 and 63 kWh m-2 for HC3v4, and 48 and 66 kWh m-2 for MACC-RAD. For daily irradiation, it ranges between 1100 and 1600 kWh m-2 for HC3v5, between 1300 and 1700 kWh m-2 for HC3v4, and between 1000 and 1850 kWh m-2 for MACC-RAD. The MACC-RAD resource show promises provided the model for cloud properties is improved

Preliminary assessment of a new SoDa service for real-time estimates and short-term forecasts of the solar radiation

International audienceMeteosat images are routinely processed at Transvalor / MINES ParisTech for assessing the solar radiation at ground by the means of the Heliosat-2 method. So far, Heliosat-2 was launched every night to update the HelioClim-3 (HC3) database with the images collected during the day. HC3 data were thus available so far at d-1. Several requirements were made by customers of HC3 for a real-time and forecast capability for horizons up to 2 h. It would help in managing the PV plants or intelligent buildings, and eventually increasing the financial gains. The major challenges to develop such a capability were pertaining to the scientific domain in order to find an accurate method, and to operational constraints. The constraints are on both sides: provider and customer. The method should be fast enough to enable the processing of large areas such as Europe, and its outputs should be such as they can be directly ingested in the own processes of the customers. The selected model is based on a local persistence and has been validated against in situ measurements. A prototype has been set up and tested for several weeks by 15 customers. The customers used the outputs of this prototype as inputs to their own processes and made their own validation by comparing the results against measurements of, e.g. PV yield. The feedback gathered from testers was overall positive and a new operational service was set up based on the prototype (http://www.soda-pro.com/soda-products/real-time-and-forecast). Further validation campaigns are planned during the second semester of 2015, either by comparing to ground measurements or performed by users with their own criteria

High spatial resolution solar atlas in Provence-Alpes-Cote d'Azur

International audienceConsidering the spatial resolution of satellite-based databases of surface solar irradiation such as HelioClim-3, the geographic scale of solar mapping that can be derived is approx. 1 / 5 000 000. This geographic scale is suitable for continent or country solar mapping. Nevertheless, customers' feedback notably states that there is a need of spatial resolution improvement. In this context of spatial resolution improvement of solar resource estimation, the project solar atlas in Provence-Alpes-Côte d'Azur (PACA), finalized in December 2010, aims at increasing spatial resolution of HelioClim-3 to derive 250 m resolution solar maps. The solar atlas accounts for the global, direct and diffuse on inclined plane or in normal incidence irradiations and their temporal variations intra and inter-annual, on a monthly basis, since February 2004. The Digital Elevation Model SRTM-V4 is used to get topographic data with a spatial resolution of approximately 100 m and a localization accuracy of typically 10 m. This topographic data is used to estimate high resolution terrain effects on HelioClim-3 derived solar radiation fields, taking into account orographic effects: * Effects of optical path length variations due to terrain elevation; * Shadow effects on direct and circumsolar diffuse radiation computed from local horizon estimation; * Horizon effects on isotropic diffuse radiation with the sky view factor estimation. These orographic phenomena are indeed the source of significant local spatial variations in solar radiation values and potentially discriminating in choosing the location, the calculation of profitability or the sizing of photovoltaic or thermodynamic solar power systems. Solar mapping with a geographic scale of 1 / 3 000 000 or more does not represent properly these local phenomena. In order to establish an accurate mapping at 250 m with associated uncertainty using HelioClim-3 data, procedures of calibration has been established with meteorological ground stations. The global horizontal irradiation is calibrated thanks to the Météo France meteorological network comprising, in PACA, about 30 automatic ground stations delivering at least daily global irradiation on horizontal plane. A strict data quality control has been applied to these ground data to guarantee their quality as reference ground-based daily irradiation data. The diffuse and direct irradiations are calibrated thanks to three specific ground stations dedicated expressly to the project, delivering one year of simultaneous 10-min global and diffuse irradiations on the horizontal plan and direct irradiation on normal incidence. Statistical analysis of direct and cross-validation estimation errors after calibration with the pyranometric ground stations has been made to establish the uncertainties associated with the solar atlas. The root mean square error of monthly irradiation estimation is about 5% (c. 5 kWh / m2) for global, direct and diffuse components on horizontal plane, without significant bias error. The accuracy of monthly direct normal irradiation is about 10% (c. 15 kWh/m2). Data from the solar atlas in PACA is available for free at www.atlas-solaire.fr. In particular, a Web Map Service (WMS), based on the Open Geographical Consortium standards, has been set up to deliver maps from the solar atlas in an interoperable and standard way

A fusion method for creating sub-hourly DNI-based TMY from long-term satellite-based and short-term ground-based irradiation data

International audienceIn order to correctly perform Concentrated Solar Power (CSP) plant electric energy output estimation, a standard approach is to consider Typical Meteorological Year (TMY) as a reference input data in CSP simulation software such as System Advisor Model or Greenius. These TMYs may be built from satellite derived irradiation databases. In order to correctly estimate the CSP electricity production, it is highly recommended to use sub-hourly DNI information. Due to limitation in spatial and temporal resolution of geostationary satellite images, satellite-based irradiation data lack good representativity in term of any sub-hourly temporal variability. To overcome this limitation, we propose an innovative fusion method to combine a one year short time series of ground-based sub-hourly irradiation data and the long-term satellite-based one to create calibrated, sub-hourly and long-term based TMY irradiation data. This method has been successfully applied in the planning of the CSP plant project in Morocco: one year and a half of high quality 10-minute irradiation data from pyranometric ground stations belonging to the Moroccan Agency for Solar Energy (MASEN) has been used with long-term hourly satellite-based irradiation data to create calibrated 10-minute DNI based TMY. The ground-based irradiation data have passed the standard quality check procedure recommended by the Baseline Solar Radiation Network for the World Climate Research Program. The satellite hourly irradiation data has been calibrated on a one year learning period of ground station data and this calibration has been verified on a subsequent half year ground station data. This calibration has been applied to the hourly long-term satellite irradiation time series from which a TMY was computed. The final and innovative step consists in introducing the site specific sub-hourly variability into the whole set of hourly daily profiles of irradiation of the TMY time series, as needed to obtain a better estimation of the CSP producible. The method uses the whole 10-minute measured irradiation data as a store of available days, normalized in terms of time between sunrise and sunset

Thulium environment in a silica doped optical fibre

Thulium-doped optical fibre amplifiers (TDFA) are developed to extend the optical telecommunication wavelength division multiplexing (WDM) bandwidth in the so-called S-band (1460-1530 nm). The radiative transition at 1.47 lm (3H4 -> 3F4) competes with a non-radiative multi-phonon de-excitation (3H4 -> 3H5). The quantum efficiency of the transition of interest is then highly affected by the phonon energy (Ep) of the material. For reliability reasons, oxide glasses are preferred but suffer from high phonon energy. In the case of silica glass, Ep is around 1100 cm-1 and quantum efficiency is as low as 2%. To improve it, phonon energy in the thulium environment must be lowered. For that reason, aluminium is added and we explore three different core compositions: pure silica, and silica slightly modified with germanium or phosphorus. The role of aluminium is studied through fluorescence decay curves, fitted according to the continuous function decay analysis. From this analysis, modification of the thulium local environment due to aluminium is evidenced

HelioClim-3: a near-real time and long-term surface solar irradiance database

International audienceHelioClim-3 is a database containing surface solar irradiance assessed every 15 min from images taken by the Meteosat series of satellites since 2004. It covers Europe, Africa and Atlantic Ocean. In average, comparison with hourly measurements made in meteorological stations yields a correlation coefficient greater than 0.9, a relative root mean square error (rRMSE) around 20% of the mean measured irradiance and a relative mean bias error (rMBE) below 2%. HelioClim-3 can be accessed via the SoDa Service (www.soda- is.org). The availability and quality of HelioClim-3 data should help in performing steps towards a better knowledge of the surface solar irradiance and its variations over recent years