Multiuser Detection for Out-of-Cell Cochannel Interference Mitigation in the IS–95 Downlink

This paper considers the application of multiuser detection techniques to improve the quality of downlink reception in a multi-cell IS–95 digital cellular communication system. In order to understand the relative performance of suboptimum multiuser detectors including the matched filter detector, optimum multiuser detection in the context of the IS–95 downlink is first considered. A reduced complexity optimum detector that takes advantage of the structural properties of the IS–95 downlink and exhibits exponentially lower complexity than the brute-force optimum detector is developed. The Group Parallel Interference Cancellation (GPIC) detector, a suboptimum, low-complexity multiuser detector that also exploits the structure of the IS–95 downlink is then developed. Simulation evidence is presented that suggests that the performance of the GPIC detector may be near-optimum in several cases. The GPIC detector is also tested on a snapshot of on-air data measured with an omnidirectional antenna in an active IS–95 system and is shown to be effective for extracting weak downlink transmissions from strong out-of-cell cochannel interference. The results of this paper suggest that the GPIC detector offers the most performance gain in scenarios where weak downlink signals are corrupted by strong out-of-cell cochannel interference.     

RTD/CMOS nanoelectronic circuits: thin-film InP-based resonanttunneling diodes integrated with CMOS circuits

The combination of resonant tunneling diodes (RTDs) and complementary metal-oxide-semiconductor (CMOS) silicon circuitry can offer substantial improvement in speed, power dissipation, and circuit complexity over CMOS-only circuits. We demonstrate the first integrated resonant tunneling CMOS circuit, a clocked 1-bit comparator with a device count of six, compared with 21 in a comparable all-CMOS design. A hybrid integration process is developed for InP-based RTDs which are transferred and bonded to CMOS chips. The prototype comparator shows sensitivity in excess of 10⁶ VIA, and achieves error-free performance in functionality testing. An optimized integration process, under development, can yield high-speed, low power circuits by lowering the high parasitic capacitance associated with the prototype circuit     

Unicast-based inference of network link delay distributions with finite mixture models

Providers of high quality-of-service over telecommunication networks require accurate methods for remote measurement of link-level performance. Recent research in network tomography has demonstrated that it is possible to estimate internal link characteristics, e.g., link delays and packet losses, using unicast probing schemes in which probes are exchanged between several pairs of sites in the network. We present a new method for estimation of internal link delay distributions using the end-to-end packet pair delay statistics gathered by back-to-back packet-pair unicast probes. Our method is based on a variant of the penalized maximum likelihood expectation-maximization (PML-EM) algorithm applied to an additive finite mixture model for the link delay probability density functions. The mixture model incorporates a combination of discrete and continuous components, and we use a minimum message length (MML) penalty for selection of model order. We present results of Matlab and ns-2 simulations to illustrate the promise of our network tomography algorithm for light cross-traffic scenarios.     

High-rate vector quantization for detection

We investigate high-rate quantization for various detection and reconstruction loss criteria. A new distortion measure is introduced which accounts for global loss in best attainable binary hypothesis testing performance. The distortion criterion is related to the area under the receiver-operating-characteristic (ROC) curve. Specifically, motivated by Sanov's theorem, we define a performance curve as the trajectory of the pair of optimal asymptotic Type I and Type II error rates of the most powerful Neyman-Pearson test of the hypotheses. The distortion measure is then defined as the difference between the area-under-the-curve (AUC) of the optimal pre-encoded hypothesis test and the AUC of the optimal post-encoded hypothesis test. As compared to many previously introduced distortion measures for decision making, this distortion measure has the advantage of being independent of any detection thresholds or priors on the hypotheses, which are generally difficult to specify in the code design process. A high-resolution Zador-Gersho type of analysis is applied to characterize the point density and the inertial profile associated with the optimal high-rate vector quantizer. The analysis applies to a restricted class of high-rate quantizers that have bounded cells with vanishing volumes. The optimal point density is used to specify a Lloyd-type algorithm which allocates its finest resolution to regions where the gradient of the pre-encoded likelihood ratio has greatest magnitude.     

Plastic material parameters and plastic anisotropy of tungsten single crystal: a spherical micro-indentation study

Enhancement of toughness is currently a critical engineering issue in tungsten metallurgy. The inherent toughness of tungsten single crystals is closely related to the capacity for local plastic slip. In this study we have investigated the plastic behavior of tungsten single crystals by means of micro-indentation experiments performed on specimens exposing (100), (110), and (111) surfaces. In parallel, FEM simulations were carried out with the Peirce–Asaro–Needleman crystal plasticity model considering both {110} 〈111〉 and {112} 〈111〉 slip systems. Plastic material parameters were identified by comparing the measured and predicted load–displacement curves as well as pile-up profiles. It is found that both measured and simulated plastic pile-up patterns on the indented surfaces exhibit significant anisotropy and orientation dependence, although the measured and simulated load–displacement curves manifest no such orientation dependence. The height and extension of pile-ups differ strongly as a function of surface orientation. The FEM simulations are able to reproduce the observed features of spherical indentation both qualitatively and quantitatively.     

Stability of limonin glucoside in beverage matrices

BACKGROUND: We completed a study over a 200‐day period examining the stability of limonin glucoside formulated into three beverage matrices. RESULTS: Beverages containing limonin glucoside were found to contain limonin (0.13–20.10 mg L^?1) during their initial testing; however, these concentrations were directly attributable to the presence of contaminating limonin in the particular lot of limonin glucoside used to prepare the beverage and did not increase over the test period. Likewise, limonin glucoside concentrations did not vary significantly, with the exception of the beverage matrix that included vitamin B₂. Exposure of the vitamin B₂‐containing beverages to light resulted in a rapid reduction in the limonin glucoside content. Liquid chromatographic–mass spectrometric and nuclear magnetic resonance results from the analyses of pre‐ and post‐light exposed beverages suggest photooxidation of the furan moiety as the likely degradation pathway. CONCLUSION: Results from this study indicate that limonin glucoside is resistant to degradation into limonin, the stability of limonin glucoside formulated into beverages exceeds six months and that limonin glucoside should not be formulated into beverages containing vitamin B₂ unless the beverages are protected from light. Published in 2008 by John Wiley & Sons, Ltd.     

Satisfying America's Fruit Gap: Summary of an Expert Roundtable on the Role of 100% Fruit Juice

The 2015 to 2020 Dietary Guidelines for Americans (DGAs) recognize the role of 100% fruit juice in health and in helping people meet daily fruit recommendations and state that 100% fruit juice is a nutrient‐dense beverage that should be a primary choice, along with water and low‐fat/fat‐free milk. The DGAs note that children are consuming 100% fruit juice within recommendations (that is, 120 to 180 mL/d for children aged 1 to 6 y and 236 to 355 mL/d for children aged 7 to 18 y). Evidence shows that compared to nonconsumers, those who consume 100% fruit juice come closer to meeting daily fruit needs and have better diet quality. In children, 100% fruit juice is associated with increased intakes of nutrients such as vitamin C, folate, and potassium. When consumed within the DGA recommendations, 100% fruit juice is not associated with overweight/obesity or childhood dental caries and does not compromise fiber intake. Preliminary data suggest that polyphenols in some 100% fruit juices may inhibit absorption of naturally occurring sugars. Given its role in promoting health and in helping people meet fruit needs, experts participating in a roundtable discussion agreed that there is no science‐based reason to restrict access to 100% fruit juice in public health nutrition policy and programs such as the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Reducing or eliminating 100% fruit juice could lead to unintended consequences such as reduced daily fruit intake and increased consumption of less nutritious beverages (for example, sugar‐sweetened beverages).     

Monitoring Phenolic Composition of Maturing Maize Stover by High Performance Liquid Chromatography and Pyrolysis/Gas Chromatography/Mass Spectrometry*

Maize stovers collected every 14 days over an 84-day growth period were subjected to high-performance liquid chromatography with electrochemical detector (HPLC-ED) and pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) in order to monitor changes in the phenolic composition. Prior to HPLC-ED analyses, ground samples were sequentially extracted with (i) methanol, (ii) 0·1M sodium hydroxide and (iii) 2M sodium hydroxide in the presence of nitrobenzene to separate, respectively, free phenolic monomers, alkali-labile phenolic monomers and alkali-resistant lignin. In turn, solution (ii) was treated with alkaline nitrobenzene to obtain (iv) alkali-labile lignin. Pyrolysis was carried out on ground native samples by using a platinum heated filament pyrolyser. Increases in the absolute phenolic concentrations in the residues of 0·1M sodium hydroxide extraction and in the ratio of alkali-resistant lignin vs total lignin were observed by HPLC-ED during the first 28–42 days of maturation, reaching a steady level in the remaining maturation period. A linear increase of syringyl units vs guaiacyl units was for found the alkali-resistant lignin fraction over the entire period of maturation. Similar trends were showed by PY/GC/MS with regard to relative lignin content and syringyl/guaiacyl ratio. Both techniques showed their usefulness to gauge changes in the phenolic composition during the lignification process.     

CONCENTRATION of ORANGE JUICE BY REVERSE OSMOSIS

Orange juice was concentrated by RO up to 50% hydraulic recovery with a polyamide membrane. Permeate fluxes and solute recoveries were determined at transmembrane pressures of 6.21 and 4.14 MPa. Pectinase treatment was required to prevent fouling and to allow Cleaning in Place procedures. Enzymatic treatment did not affect permeate flux or solute recoveries. Overall recovery of sugars, organic acids, and flavor-volatile components was approximately 93%.