Design and Characterization of the CLIMPAQ,Chamber for Laboratory Investigations of Materials,Pollution and Air Quality*

A test chamber has been developed in order to provide a small and simple emission testing facility capable of testing construction products in a climate where the important climatic parameters such as temperature, ventilation rate and air velocity can be varied independently around typical indoor values. The test chamber CLIMPAQ is made of panes of window glass. Other main surface materials are stainless steel and eloxated aluminium. The chamber has a volume of 50.9 litres and is designed to meet the requirements for quantifying air pollution. In this investigation human subjects acted as air pollution judges, and chemical characterization of the air pollution was carried out. Carpet, linoleum, wall paint and seal- ant were tested simultaneously in the CLIMPAQ and in four other chambers ranging from a full-scale chamber of 28 m³ to a field and laboratory emission cell of 3.5· 10^?5m³. Product ranking is the same in all chambers for the sensory measurements. Emission rates based on sensory measurements differ for all products less than 100 % except for tests in a 3-litre chamber where emission rates were higher. Chemical measurements differ up to approximately 10 times for the same product in different chambers. Deviations appear to be the result of different environmental parameters in the various chambers. Low air concentrations or high specific ventilation rates seem to increase emissions, while differences in air velocities and sink properties may also be the cause of differences in emission rates.     

The fundamentals of average local variance--Part I: Detecting regular patterns.

The method of average local variance (ALV) computes the mean of the standard deviation values derived for a 3 x 3 moving window on a successively coarsened image to produce a function of ALV versus spatial resolution. In developing ALV, the authors used approximately a doubling of the pixel size at each coarsening of the image. They hypothesized that ALV is low when the pixel size is smaller than the size of scene objects because the pixels on the object will have similar response values. When the pixel and objects are of similar size, they will tend to vary in response and the ALV values will increase. As the size of pixels increase further, more objects will be contained in a single pixel and ALV will decrease. The authors showed that various cover types produced single peak ALV functions that inexplicitly peaked when the pixel size was 1/2 to 3/4 of the object size. This paper reports on work done to explore the characteristics of the various forms of the ALV function and to understand the location of the peaks that occur in this function. The work was conducted using synthetically generated image data. The investigation showed that the hypothesis originally proposed in is not adequate. A new hypothesis is proposed that the ALV function has peak locations that are related to the geometric size of pattern structures in the scene. These structures are not always the same as scene objects. Only in cases where the size of and separation between scene objects are equal does the ALV function detect the size of the objects. In situations where the distance between scene objects are larger than their size, the ALV function has a peak at the object separation, not at the object size. This work has also shown that multiple object structures of different sizes and distances in the image provide multiple peaks in the ALV function and that some of these structures are not implicitly recognized as such from our perspective. However, the magnitude of these peaks depends on the response mix in the structures, complicating their interpretation and analysis. The analysis of the ALV Function is, thus, more complex than that generally reported in the literature.     

RF4CE有何要求

消费电子射频(RF4CE)联盟是针对消费类电子产品遥控器的一种协议标准.松下、飞利浦、三星电子和索尼公司组成的企业联盟正在推动这一标准化进程.它们的目标是,通过运用于遥控器的双向RE通信实现高可靠性和众多新颖功能,从而向消费者提供更多价值.     

Selecting informative data for developing peptide-MHC binding predictors using a query by committee approach

Strategies for selecting informative data points for training prediction algorithms are important, particularly when data points are difficult and costly to obtain. A Query by Committee (QBC) training strategy for selecting new data points uses the disagreement between a committee of different algorithms to suggest new data points, which most rationally complement existing data, that is, they are the most informative data points. In order to evaluate this QBC approach on a real-world problem, we compared strategies for selecting new data points. We trained neural network algorithms to obtain methods to predict the binding affinity of peptides binding to the MHC class I molecule, HLA-A2. We show that the QBC strategy leads to a higher performance than a baseline strategy where new data points are selected at random from a pool of available data. Most peptides bind HLA-A2 with a low affinity, and as expected using a strategy of selecting peptides that are predicted to have high binding affinities also lead to more accurate predictors than the base line strategy. The QBC value is shown to correlate with the measured binding affinity. This demonstrates that the different predictors can easily learn if a peptide will fail to bind, but often conflict in predicting if a peptide binds. Using a carefully constructed computational setup, we demonstrate that selecting peptides with a high QBC performs better than low QBC peptides independently from binding affinity. When predictors are trained on a very limited set of data they cannot be expected to disagree in a meaningful way and we find a data limit below which the QBC strategy fails. Finally, it should be noted that data selection strategies similar to those used here might be of use in other settings in which generation of more data is a costly process.     

Classification of slice-based VBR video traffic and estimation of link loss by exceedance

Classification of a video stream is an essential preliminary step to estimate the bit loss when the video stream is transmitted over a communication network. In this paper, we classify the video frames by the average frame size and estimate the bit loss for each class when the bitrate exceeds the capacity of the bottleneck link. The video stream under study is encoded using the explicit slice-based H.264/AVC encoding scheme. This scheme reduces the burstiness of regular H.264/AVC encoded video by removing the traditional GOP structure. Instead, a repetitive combination of intracoded and predicted slices is employed, thereby introducing a specific dependence structure in the video data. We consider a bufferless model of the communication system and evaluate the channel capacity required to give a maximum allowed loss rate for each class.Due to the high variability, non-stationarity and non-homogeneity of the underlying video data, the obtained classes are checked regarding the dependence and distribution structure of the data. The high quantiles of the losses are estimated for each class.     

Hydroprocessing of Bio-Oils and Oxygenates to Hydrocarbons. Understanding the Reaction Routes

To produce diesel fuel from renewable organic material such as vegetable oils, it has for a number of years been known that triglycerides can be hydrogenated into linear alkanes in a refinery hydrotreating unit over conventional sulfided hydrodesulfurization catalysts. A number of new reactions occur in the hydrotreater, when a biological component is introduced, and experiments were conducted to obtain a more detailed understanding of these mechanisms. The reaction pathways were studied both in model compound tests and in real feed tests with mixtures of straight-run gas oil and rapeseed oil. In both sets of experiments, the hydrogenation of the oxygen containing compounds was observed to proceed either via a hydrodeoxygenation (HDO) route or via a decarboxylation route. The detailed pathway of the HDO route was further illuminated by studying the hydroprocessing of methyl laurate into n-dodecane. The observed reaction intermediates did not support a simple stepwise hydrogenation of the aldehyde formed after hydrogenation of the connecting oxygen in the ester. Instead, it is proposed that the aldehyde formed is enolized before further hydrogenation. The existence of an enol intermediate was further corroborated by the observation that a ketone lacking α-hydrogen (that cannot be directly enolized) had a much lower reactivity than a corresponding ketone with α-hydrogen. In real feed tests, the complete conversion of rapeseed oil into linear alkanes at mild hydrotreating conditions was demonstrated. From the gas and liquid yields, the relative rates of HDO and decarboxylation were calculated in good agreement with the observed distribution of the n-C₁₇/n-C₁₈ and n-C₂₁/n-C₂₂ formed. The hydrogen consumption associated with each route is deduced, and it was shown that hydrogen consumed in the water-gas-shift and methanization reactions may add significant hydrogen consumption to the decarboxylation route. The products formed exhibited high cetane values and low densities. The challenges of introducing triglycerides in conventional hydrotreating units are discussed. It is concluded that hydrotreating offers a robust and flexible process for converting a wide variety of alternative feedstocks into a green diesel fuel that is directly compatible with existing fuel infrastructure and engine technology.     

Comparison Of Volatile Organic Compounds From Processed Paper And Toners From Office Copiers And Printers: Methods,Emission Rates,And Modeled Concentrations

The emission of volatile organic compounds (VOC) from nine toner powders and eleven types of processed paper from photocopying machines (6), laser (3) and matrix printers (21, and one carbonless copy fm has been measured. A total of 61 VOC from toner powders were identified by heating (185 °C) the powder for three minutes for thermal desorption and by gas chromatography followed by the use of low and high resolution EI and CI mass spectrometry. VOC from processed paper were analyzed by headspace sampling on Tenax TA from nylon bags. Thirty-one VOC with a wide range of volatility and persistency were identified from processed paper. The total VOC emission from the various types of paper differed substantially. Using the field and laboratory emission cell (FLEC), the calculated initial emission rate of styrene was 5 μg m^?2h^?1 from a freshly processed paper The VOC emission from machines and the processed paper can be reduced by proper choice of o m e equipment. However, an evaluation should consider all potential pollutants.     

Online short-term solar power forecasting

This paper describes a new approach to online forecasting of power production from PV systems. The method is suited to online forecasting in many applications and in this paper it is used to predict hourly values of solar power for horizons of up to 36 h. The data used is 15-min observations of solar power from 21 PV systems located on rooftops in a small village in Denmark. The suggested method is a two-stage method where first a statistical normalization of the solar power is obtained using a clear sky model. The clear sky model is found using statistical smoothing techniques. Then forecasts of the normalized solar power are calculated using adaptive linear time series models. Both autoregressive (AR) and AR with exogenous input (ARX) models are evaluated, where the latter takes numerical weather predictions (NWPs) as input. The results indicate that for forecasts up to 2 h ahead the most important input is the available observations of solar power, while for longer horizons NWPs are the most important input. A root mean square error improvement of around 35% is achieved by the ARX model compared to a proposed reference model.