Energy Aware Signal Processing for Software Defined Radio Baseband Implementation

The fast pacing diversity and evolution of wireless communications require a wide variety of baseband implementations within a short time-to-market. Besides, the exponentially increased design complexity and design cost of deep sub-micron silicon highly desire the designs to be reused as much as possible. This yields an increasing demand for reconfigurable/ programmable baseband solutions. Implementing all baseband functionalities on programmable architectures, as foreseen in the tier-2 SDR, will become necessary in the future. However, the energy efficiency of SDR baseband platforms is a major concern. This brings a challenging gap that is continuously broadened by the exploding baseband complexity. We advocate a system level approach to bridge the gap. Specifically, we fully leverage the advantages (programmability) of SDR platforms to compensate its disadvantages (energy efficiency). Highly flexible and dynamic baseband signal processing algorithms are designed and implemented to exploit the abundant dynamics in the environment and the user requirement. Instead of always performing the best effort, the baseband can dynamically and autonomously adjust its work load to optimize the average energy consumption. In this paper, we will introduce such baseband signal processing techniques optimized for SDR implementations. The methodology and design steps will be presented together with 3 representative case studies in HSDPA, WiMAX and 3GPP LTE.     

Food Process Engineering: The Last 25 Years and Challenges Ahead

In the first part of this contribution, an overview is given of some of the main developments in food process engineering in the last 25 years of the 20th century. This overview is, of course, colored by the personal experience of the authors, but a sincere effort was made to maintain a general perspective. Topics that will be briefly discussed are: progress in understanding how to control food microstructure formation during processing, separation processes, conversion processes and stabilization processes, progress in flavor technology and understanding of flavor retention during processing and release. In the 2nd part, in our view, the most exiting future developments are briefly discussed. The major items here are: processing requirements for functional foods, integrated process design approaches, application of novel‘fields’in food processes,‘precision’processing, supply chain approaches to food manufacturing, and more.     

Variables influencing food perception reviewed for consumer-oriented product development

Consumer wishes have to be translated into product characteristics to implement consumer-oriented product development. Before this step can be made, insight in food-related behavior and perception of consumers is necessary to make the right, useful, and successful translation. Food choice behavior and consumers' perception are studied in many disciplines. Models of food behavior and preferences therefore were studied from a multidisciplinary perspective. Nearly all models structure the determinants related to the person, the food, and the environment. Consequently, the overview of models was used as a basis to structure the variables influencing food perception into a model for consumer-oriented product development. To this new model, referred to as food perception model, other variables like time and place as part of consumption moment were added. These are important variables influencing consumers' perception, and therefore of increasing importance to consumer-oriented product development nowadays. In further research, the presented food perception model is used as a tool to implement successful consumer-oriented product development.     

Energy Aware Algorithm and Implementation of SDR Oriented HSDPA Chip Level Equalizer

The flexibility and programmability of SDR come at the expense of reduced efficiency and increased energy consumption. This is usually considered as the penalty of SDR. However, the flexibility and programmability have great potentials for improving the system-wide efficiency if they are properly exploited. In this paper, we present a HSDPA chip equalizer that is explicitly designed for SDR implementations. The first SDR-specific feature of our work is the multi-mode operation based on heterogeneous algorithms. The proposed equalizer combines an optimized LMS variant (with subspace-aware extension) and an optimized SRI-RLS algorithm based on QRD. Instead of always applying the powerful SRI-RLS algorithm, the equalizer switches to simple LMS-variant when possible. With negligible BER degradation, the multi-mode operation can reduce 60% of the cycle-count on TI TMS320C6713 for 3GPP case 4 with 16QAM modulation. The proposed equalizer framework also incorporates a generic, robust and efficient scheme for equalization-length adaptation. The length-adaptation scheme can make very fast run-time decision based on an efficient policy-template, which is optimized with large training set at design time. We test 14 representative channel profiles specified in ITU-R M.1225, 3GPP TR 25.943 and 3GPP TS 25.101. Comparing to worst-case based design the length-adaptation achieves more than 10× cycle-count reductions for ten of the cases.     

Speciation of Se in Bertholletia excelsa (Brazil nut): A hard nut to crack?

A separation method based on ion-pairing liquid chromatography was combined with both elemental (inductively coupled plasma mass spectrometry (ICP-MS)) and molecular (electrospray tandem mass spectrometry (ES-MS-MS)) mass spectrometry in order to unravel the identity of the Se-species present in the complex matrix of Brazil nuts rich in Se. Via enzymatic digestion, Se-species were released from the matrix. Subsequently the species were separated and the Se was monitored on-line by ICP-MS. By HPLC–ES-MS-MS, the species were identified based on their molecular mass and their specific product ions. The main compound was identified as Se-Methionine. Another compound was identified as Se-Cystine, partly on the basis of the isotopic pattern of Se. This research was further extended to the analyses of in vitro gastrointestinal digests of the Brazil nuts. These digests were analyzed for their Se-content and screened for the presence of the different Se-species by HPLC–ICP-MS. In both the gastric and the intestinal digests, we were able to identify the Se-species as Se-Methionine and Se-Cystine by HPLC–ES-MS-MS. By coupling HPLC to both elemental and molecular mass spectrometry, the species present in Brazil nuts and supposedly extractable by our body were fully characterized.     

RNRA and neutron threshold analyses of thick lithium coatings deposited by sputter evaporation

Li coatings on various substrates have numerous applications: Boron neutron capture therapy, super conducting tokamak, etc.Unfortunately the main difficulty using Li is its reactivity in air and diffusion into metals. It is the only metal that reacts with nitrogen at room temperature and it tarnishes and oxidizes rapidly in air.In this work, we investigate how to profile thick Li layers (50 μm) deposited on SiO₂ substrates by a method based on plasma sputtering, involving both DC sputtering and evaporation simultaneously.A thick Li layer (≈10 μm) was covered with a thin stainless steel layer to prevent oxidation during transfer of the sample from the sputtering chamber and the accelerator. Li coatings were investigated by RNRA and neutron threshold reaction to obtain interdiffusion profiles of the different components and their concentration. The depth profile using the ⁷Li(p,γ)⁸Be^∗ resonance nuclear reaction occurring at 440 keV allows us to obtain Li concentration versus depth up to 50 μm.Preliminary results indicate that homogeneous Li layers can be obtained and protected against air, even though it diffuses into the encapsulated layers.     

Experimental results from an ECR source using an octupole

The large superconducting ECR source, ECREVIS (Louvain-la-Neuve) has shown better charge state distribution (CSD) than smaller sources like MINIMAFIOS or the Berkeley source. Computer simulation indicates that the reason could be a lower average electron energy in the smaller sources. It has been suggested by Jongen that the size of the magnetic gradients in the source could be the energy limiting factor, and that the average electron energy could be increased by replacing the usual sextupole by an octupole. After an extensive series of tests, the sextupole of the Berkeley source was replaced by an octupole. After modification, the CSD have been substantially improved in the direction of higher charge states, with a substantial reduction of low charge state intensity. The intensity of higher charge states like argon 14+ or krypton 18+ increased by one order of magnitude. The new CSD are now very similar to those of the large ECREVIS source, indicating a probable gain in average electron energy.     

Blistering of the selected materials irradiated by intense 200 keV proton beam

Formation of blisters on the surfaces of metal targets made of the selected materials was studied. The targets were irradiated by 100-200 keV, 1-2 mA proton beam up to the doses above 10²⁴ m⁻². Real-time monitoring of the target surface was performed with a set of in situ optical surface diagnostics that allows detection of the moment of blisters appearance.The overview of experimental setup and the results of testing of different materials are presented. The number and the size of blisters gradually increase during the irradiation. Critical fluence of blistering strongly depends on the target temperature, proton energy and surface machining method. The features of blistering under the proton beam irradiation and the effects of hydrogen diffusion and interaction with the target lattice are discussed.     

Control of morphology and nanostructure of copper and cobalt oxalates: effect of complexing ions, polymeric additives and molecular weight

Precipitated oxalates are often nanostructured and can be used as precursors for nanostructured oxides for different applications. The modification of the particle shape and nanostructures of both copper and cobalt oxalates has been demonstrated using polymeric additives or complexing counter-ions. In the case of cobalt oxalate the characteristic elongated rod particle shape (axial ratio of 10) can be modified by using polymethymethacrylate (PMMA) to produce particles with lower axial ratios of 2, through cubes all the way to platelets (axial ratio 0.2). The PMMA inhibits the growth of the particles along the [101] direction more and more strongly as the concentration of the polymer increases. The crystallite size from XRD line broadening is not modified by the PMMA indicating that the PMMA does not influence the nucleation and growth but modifies the aggregation kinetics. Copper oxalates precipitated in the presence of different cellulose derived polymers with different molecular weights and functional groups (methyl and propyl) showed sensitivity to both molecular weight and functional group. Higher molecular weights did not influence the copper oxalate particle shape, whereas methyl cellulose gave elongated particles and propyl celluloses gave platelet like particles. Copper oxalate precipitated in the presence of acetate counter ions gave platelets with an axial ratio of 0.15 compared to the cushion-like morphology (axial ratio 0.5). The primary crystallites were more elongated along the [001] direction in the presence of acetate, modifying the proportion of the hydrophobic and hydrophilic surfaces and hence influencing the aggregation kinetics and particle shape. The copper and cobalt oxalate particle formation seems to be dominated by the primary particle aggregation with the different additives interacting specifically with different crystallographic faces of the primary particles. By tuning this interaction particles with different shapes and substructures can be formed.     

Does attention capacity moderate the effect of driver distraction in older drivers?

With age, a decline in attention capacity may occur and this may impact driving performance especially while distracted. Although the effect of distraction on driving performance of older drivers has been investigated, the moderating effect of attention capacity on driving performance during distraction has not been investigated yet. Therefore, the aim was to investigate whether attention capacity has a moderating effect on older drivers’ driving performance during visual distraction (experiment 1) and cognitive distraction (experiment 2). In a fixed-based driving simulator, older drivers completed a driving task without and with visual distraction (experiment 1, N = 17, mean age 78 years) or cognitive distraction (experiment 2, N = 35, mean age 76 years). Several specific driving measures of varying complexity (i.e., speed, lane keeping, following distance, braking behavior, and crashes) were investigated. In addition to these objective driving measures, subjective measures of workload and driving performance were also included. In experiment 1, crash occurrence increased with visual distraction and was negatively related to attention capacity. In experiment 2, complete stops at stop signs decreased, initiation of braking at pedestrian crossings was later, and crash occurrence increased with cognitive distraction. Interestingly, for a measure of lane keeping (i.e., standard deviation of lateral lane position (SDLP)), effects of both types of distraction were moderated by attention capacity. Despite the decrease of driving performance with distraction, participants estimated their driving performance during distraction as good. These results imply that attention capacity is important for driving. Driver assessment and training programs might therefore focus on attention capacity. Nonetheless, it is crucial to eliminate driver distraction as much as possible given the deterioration of performance on several driving measures in those with low and high attention capacity.