Exploiting quantization and spatial correlation in virtual-noise modeling for distributed video coding

Aiming for low-complexity encoding, video coders based on Wyner–Ziv theory are still unsuccessfully trying to match the performance of predictive video coders. One of the most important factors concerning the coding performance of distributed coders is modeling and estimating the correlation between the original video signal and its temporal prediction generated at the decoder.One of the problems of the state-of-the-art correlation estimators is that their performance is not consistent across a wide range of video content and different coding settings. To address this problem we have developed a correlation model able to adapt to changes in the content and the coding parameters by exploiting the spatial correlation of the video signal and the quantization distortion.In this paper we describe our model and present experiments showing that our model provides average bit rate gains of up to 12% and average PSNR gains of up to 0.5 dB when compared to the state-of-the-art models. The experiments suggest that the performance of distributed coders can be significantly improved by taking video content and coding parameters into account.     

A Highly Conductive Titanium Oxynitride Electron-Selective Contact for Efficient Photovoltaic Devices

High-quality carrier-selective contacts with suitable electronic properties are a prerequisite for photovoltaic devices with high power conversion efficiency (PCE). In this work, an efficient electron-selective contact, titanium oxynitride (TiO_xN_y), is developed for crystalline silicon (c-Si) and organic photovoltaic devices. Atomic-layer-deposited TiO_xN_y is demonstrated to be highly conductive with a proper work function (4.3 eV) and a wide bandgap (3.4 eV). Thin TiO_xN_y films simultaneously provide a moderate surface passivation and enable a low contact resistivity on c-Si surfaces. By implementation of an optimal TiO_xN_y-based contact, a state-of-the-art PCE of 22.3% is achieved for a c-Si solar cell featuring a full-area dopant-free electron-selective contact. Simultaneously, conductive TiO_xN_y is proven to be an efficient electron-transport layer for organic photovoltaic (OPV) devices. A remarkably high PCE of 17.02% is achieved for an OPV device with an electron-transport TiO_xN_y layer, which is superior to conventional ZnO-based devices with a PCE of 16.10%. Atomic-layer-deposited TiO_xN_y ETL on a large area with a high uniformity may help accelerate the commercialization of emerging solar technologies.     

Faithful Fabrication of Biocompatible Multicompartmental Memomicrospheres for Digitally Color‐Tunable Barcoding

Barcodes have attracted widespread attention, especially for the multiplexed bioassays and anti‐counterfeiting used toward medical and biomedical applications. An enabling gas‐shearing approach is presented for generating 10‐faced microspherical barcodes with precise control over the properties of each compartment. As such, the color of each compartment could be programmatically adjusted in the 10‐faced memomicrospheres by using pregel solutions containing different combinations of fluorescent nanoparticles. During the process, three primary colors (red, green, and blue) are adopted to obtain up to seven merged fluorescent colors for constituting a large amount of coding as well as a magnetic compartment, capable of effective and robust high‐throughput information‐storage. More importantly, by using the biocompatible sodium alginate to construct the multicolor microspherical barcodes, the proposed technology is likely to advance the fields of food and pharmaceutics anti‐counterfeiting. These remarkable properties point to the potential value of gas‐shearing in engineering microspherical barcodes for biomedical applications in the future.     

Identification of Individual Exosome‐Like Vesicles by Surface Enhanced Raman Spectroscopy

Exosome‐like vesicles (ELVs) are a novel class of biomarkers that are receiving a lot of attention for the detection of cancer at an early stage. In this study the feasibility of using a surface enhanced Raman spectroscopy (SERS) based method to distinguish between ELVs derived from different cellular origins is evaluated. A gold nanoparticle based shell is deposited on the surface of ELVs derived from cancerous and healthy cells, which enhances the Raman signal while maintaining a colloidal suspension of individual vesicles. This nanocoating allows the recording of SERS spectra from single vesicles. By using partial least squares discriminant analysis on the obtained spectra, vesicles from different origin can be distinguished, even when present in the same mixture. This proof‐of‐concept study paves the way for noninvasive (cancer) diagnostic tools based on exosomal SERS fingerprinting in combination with multivariate statistical analysis.     

Preliminary experience with a new double-echo half-Fourier single-shot turbo spin echo acquisition in the characterization of liver lesions

A new double-echo half-Fourier single-shot turbo spin echo technique has been implemented in which two images are obtained per excitation pulse, one with an echo time (TE) of 60 ms and another with a TE of 438 ms. The acquisition window per image is 380 ms and is determined by the echo spacing of 4.3 ms and the echo train length of 88 for images with resolution of 160×256. No breath holding was performed. The aim of the study was to test whether the additional information of the late TE image improves the characterization of liver lesions. Twenty-eight patients with 39 focal liver lesions (9 cysts, 11 hemangiomas, and 19 solid lesions) were imaged with the new technique, and signal intensity (SI) ratios of lesion and liver were obtained. At-test analysis showed that in the TE 60 ms image, SI ratios of cysts and hemangiomas were not significantly different, whereas in the TE 438 ms images the two types of lesions can be classified. Signal intensity ratios of solid lesions were in both images clearly lower than those of cysts and hemangiomas. The technique, therefore, seems a promising and straightforward new tool for the characterization of liver lesions.     

Monolithic Perovskite/Silicon Tandems with >28% Efficiency: Role of Silicon-Surface Texture on Perovskite Properties

Textured silicon wafers used in silicon solar cell manufacturing offer superior light trapping, which is a critical enabler for high-performance photovoltaics. A similar optical benefit can be obtained in monolithic perovskite/silicon tandem solar cells, enhancing the current output of the silicon bottom cell. Yet, such complex silicon surfaces may affect the structural and optoelectronic properties of the overlying perovskite films. Here, through extensive characterization based on optical and microstructural spectroscopy, it is found that the main effect of such substrate morphology lies in an altering of the photoluminescence response of the perovskite, which is associated with thickness variations of the perovskite, rather than lattice strain or compositional changes. With this understanding, the design of high-performance perovskite/silicon tandems is rationalized, yielding certified power conversion efficiencies of >28%.     

Decoder-driven mode decision in a block-based distributed video codec

Distributed Video Coding (DVC) is a video coding paradigm in which the computational complexity is shifted from the encoder to the decoder. DVC is based on information theoretic results suggesting that, under ideal conditions, the same rate-distortion performance can be achieved as for traditional video codecs. In practice however, there is still a significant performance gap between the two coding architectures. One of the main reasons for this gap is the lack of multiple coding modes in current DVC solutions. In this paper, we propose a block-based distributed video codec that supports three coding modes: Wyner–Ziv, skip, and intra. The mode decision process is entirely decoder-driven. Skip blocks are selected based on the estimated accuracy of the side information. The choice between intra and Wyner–Ziv coding modes is made on a rate-distortion basis, by selecting the coding mode with the lowest rate while assuring equal distortion for both modes. Experimental results illustrate that the proposed block-based architecture has some advantages over classical bitplane-based approaches. Introducing skip and intra coded blocks yields average bitrate gains of up to 33.7% over our basic configuration supporting Wyner–Ziv mode only, and up to 29.7% over the reference bitplane-based DISCOVER codec.     

Effect of pan-frying in different culinary fats on the fatty acid profile of pork

This study was set up to determine how pan-frying either without culinary fat or with different culinary fats (polyunsaturated fatty acids (PUFA)-enriched culinary fat, olive oil and margarine) affects the fatty acid (FA) composition of pork. The meat samples (longissimus thoracis (LT)) originated from pigs fed different dietary fat sources (animal fat, soybean oil or linseed oil) and thus had different FA compositions before frying. Pan-frying resulted in considerable increases in the meat total-FA content, although this was not always significant and highly variable, despite standardisation of the frying process. The FA composition of the pan-fried meat tended to become similar to that of the culinary fat used, and the extent of changes in the content of a particular FA was relative to the FA gradient from the culinary fat to the meat. However, this was also dependent on the culinary fat used, since frying in olive oil appeared to affect the FA composition of the meat more than did frying in the other culinary fats. Differences in FA composition of meat resulting from different animal feeding treatments remained unchanged after pan-frying without fat, they became smaller after frying in margarine and PUFA-enriched culinary fat, whereas frying in olive oil largely masked the initial FA profile differences. Long chain PUFA (LCPUFA) in the meat were not significantly lost by the frying process, but their proportion was influenced by the uptake of the culinary fat.     

Nitrogen balances and nitrogen use efficiency of intensive vegetable rotations in South East Asian tropical Andisols

Nitrogen fertilizer application rates in intensive vegetable production in (South) East Asia have increased exponentially over the past decades, including in the low income countries. While there have been reports of excessive N inputs from e.g. Vietnam, Thailand and Indonesia, very little quantitative knowledge exists on the real extent of the problem. We calculated N balances and agronomic N use efficiencies (ANUE) for a number of typical intensive vegetable rotations in the highlands of Central Java, Indonesia, on fertile Andisols, both for individual cropping cycles (short term) as for 6 consecutive cropping cycles (long term). This was done for farmers practice (FP) treatments, and improved practice (IP) treatments, where N fertilization was significantly reduced. Yields were in general similar in FP and IP, but tended to be slightly higher in IP, with some significant differences. Both the short and long term N balances were always positive and usually very high. Short term N balances ranged from 9 to 559 kg N ha⁻¹ and 219 to 885 kg N ha⁻¹ in IP and FP, respectively, while short term ANUE ranged from 8 to 67 and 4 to 39% in IP and FP, respectively. Long term N balances ranged from 627 to 1,885 kg N ha⁻¹ and 962 to 3,808 kg N ha⁻¹ in IP and FP, respectively, indicating a massive excess of N supply especially in FP. N balances can thus be drastically reduced with no negative impacts on yield, on the contrary. Soil mineral N in the 0–25 cm layer was in general not very high (6.5–38.8 mg N kg⁻¹ soil) and not systematically different between IP and FP, probably as a result of excessive NO₃ ⁻ leaching. Therefore, topsoil mineral N seems to have only limited indicator value under these conditions. Because denitrification losses in these soils are not very high, most N in excess of the crop requirements will be lost by leaching. Quantitative data on N balances as obtained here may be used to sensitize policy makers and farmers about the threat of current farming practices to the environment, and to improve economic performance.