Neural networks for nonlinear discriminant analysis in continuous speech recognition

In this paper neural networks for Nonlinear Discriminant Analysis in continuous speech recognition are presented. Multilayer Perceptrons are used to estimate a-posteriori probabilities for Hidden-Markov Model states, which are the optimal discriminant features for the separation of the HMM states. The a-posteriori probabilities are transformed by a principal component analysis to calculate the new features for semicontinuous HMMs, which are trained by the known Maximum-Likelihood training. The nonlinear discriminant transformation is used in speaker-independent phoneme recognition experiments and compared to the standard Linear Discriminant Analysis technique

Autonomous measurement system for photovoltaic and radiometer soiling losses

Soiling can greatly reduce both the efficiency of photovoltaic (PV) installations and the signals of radiometers. The knowledge of the current soiling losses of a PV installation can be used to optimize the cleaning schedule and to avoid false alarms related to other issues that might cause underperformance. Underperformance can be detected by comparing measured to modeled PV production derived using pyranometer or reference cell measurements. Soiled pyranometers or reference cells lead to too low modeled PV production so that PV soiling or other errors might not be detected. So far, soiling sensors either require frequent cleaning or they use indirect measurements to derive the soiling loss (e.g., analysis of backscattering signal or imaging of dust on a glass surface). Currently, the soiling loss of pyranometers or outdoor reference cells uses the comparison to another frequently cleaned device of the same model. To avoid time-consuming maintenance of the sensors and to avoid additional sensors as much as possible, we developed a new method for measuring PV and radiometer soiling losses. The method makes use of a characterized lamp that is protected from soiling by a collimator and that illuminates the pyranometer or reference cell each night for some time. Comparing the signals of one night to the signal obtained at a night shortly after the last cleaning of the sensor, its soiling loss can be derived. To validate the measurements of soiling losses for the pyranometer and the reference cell, the soiling losses of the devices are also derived by comparing their signals to those of a clean sensor of the same type. These reference instruments are calibrated relative to the test devices so that deviations indicate the soiling loss of the test sensors. The first outdoor tests with 4 months of data show a good agreement with the reference measurements of the soiling losses. The accuracy of the method is estimated to be similar to that of the reference method, which involves the daily cleaning of the reference devices

Deep Sequencing of MYC DNA-Binding Sites in Burkitt Lymphoma

BACKGROUND: MYC is a key transcription factor involved in central cellular processes such as regulation of the cell cycle, histone acetylation and ribosomal biogenesis. It is overexpressed in the majority of human tumors including aggressive B-cell lymphoma. Especially Burkitt lymphoma (BL) is a highlight example for MYC overexpression due to a chromosomal translocation involving the c-MYC gene. However, no genome-wide analysis of MYC-binding sites by chromatin immunoprecipitation (ChIP) followed by next generation sequencing (ChIP-Seq) has been conducted in BL so far. METHODOLOGY/PRINCIPAL FINDINGS: ChIP-Seq was performed on 5 BL cell lines with a MYC-specific antibody giving rise to 7,054 MYC-binding sites after bioinformatics analysis of a total of approx. 19 million sequence reads. In line with previous findings, binding sites accumulate in gene sets known to be involved in the cell cycle, ribosomal biogenesis, histone acetyltransferase and methyltransferase complexes demonstrating a regulatory role of MYC in these processes. Unexpectedly, MYC-binding sites also accumulate in many B-cell relevant genes. To assess the functional consequences of MYC binding, the ChIP-Seq data were supplemented with siRNA- mediated knock-downs of MYC in BL cell lines followed by gene expression profiling. Interestingly, amongst others, genes involved in the B-cell function were up-regulated in response to MYC silencing. CONCLUSION/SIGNIFICANCE: The 7,054 MYC-binding sites identified by our ChIP-Seq approach greatly extend the knowledge regarding MYC binding in BL and shed further light on the enormous complexity of the MYC regulatory network. Especially our observations that (i) many B-cell relevant genes are targeted by MYC and (ii) that MYC down-regulation leads to an up-regulation of B-cell genes highlight an interesting aspect of BL biology

Progress in heliostat development

Abstract not availableAndreas Pfahl, Joe Coventry, Marc Röger, Fabian Wolfertstetter, Juan Felipe Vásquez-Arango, Fabian Gross, Maziar Arjomandi, Peter Schwarzbözl, Mark Geiger, Phillip Liedk

Techno-Economic Assessment of Soiling Losses and Mitigation Strategies for Solar Power Generation

The light-collecting surfaces of solar power systems cover areas of more than 3,000 km2 worldwide, with PV modules accounting for the majority. An often-neglected problem is the contamination of these surfaces, so-called “soiling,” which leads to significantly reduced energy yields, especially in high-insolation arid and semi-arid climates. Indeed, an inadequate soiling mitigation strategy in high solar-potential and soiling-prone locations such as China, India, or the Middle East can cancel out in few weeks the impressive progress in solar cell and CSP efficiency made in recent decades. Currently, there is no one-solution-fits-all to the problem of soiling due to its site-specific and seasonal variability, differences in local energy costs, and the availability and costs of resources required for cleaning, such as water or labor. Indeed, frequent cleaning can increase the energy generation costs and water consumption dramatically, leading to a need for water-less and inexpensive soiling mitigation technologies. Our analysis indicates that in addition to optimized cleaning plans, automated cleaning machines, anti-soiling coatings, tracking system modifications, PV module design, improved soiling monitoring, and site adaption can be economically feasible and effective solutions to reduce the negative impact of soiling. Other technologies like electrodynamic screens or dew mitigation need further research and development to improve functionality and become economically relevant for large-scale application

The enerMENA Meteorological Network - Solar Radiation Measurements in the MENA Region

Solar irradiance and ancillary meteorological data are needed for solar resource assessment. Accurate measurements are required for comparison and adjustment of long‐term satellite data. Furthermore, reliable irradiance measurements are needed to validate Direct Normal Irradiance (DNI) forecasting methods. Starting in 2010, ten meteorological stations have been installed in the Middle East and Northern Africa (MENA) within the enerMENA projec