A Low-Power Multithreaded Processor for Software Defined Radio

Embedded digital signal processors for software defined radio have stringent design constraints including high computational bandwidth, low power consumption, and low interrupt latency. Furthermore, due to rapidly evolving communication standards with increasing code complexity, these processors must be compiler-friendly, so that code for them can quickly be developed in a high-level language. In this paper, we present the design of the Sandblaster Processor, a low-power multithreaded digital signal processor for software defined radio. The processor uses a unique combination of token triggered threading, powerful compound instructions, and SIMD vector operations to provide real-time baseband processing capabilities with very low power consumption. We describe the processor’s architecture and microarchitecture, along with various techniques for achieving high performance and low power dissipation. We also describe the processor’s programming environment and the SB3010 platform, a complete system-on-chip solution for software defined radio. Using a super-computer class vectorizing compiler, the SB3010 achieves real-time performance in software on a variety of communication protocols including 802.11b, GPS, AM/FM radio, Bluetooth, GPRS, and WCDMA. In addition to providing a programmable platform for SDR, the processor also provides efficient support for a wide variety of digital signal processing and multimedia applications. Michael Schulte received a B.S. degree in Electrical Engineering from the University of Wisconsin-Madison in 1991, and M.S. and Ph.D. degrees in Electrical Engineering from the University of Texas at Austin in 1992 and 1996, respectively. From 1996 to 2002, he was an assistant and associate professor at Lehigh University, where he directed the Computer Architecture and Arithmetic Research Laboratory. He is currently an assistant professor at the University of Wisconsin-Madison, where he leads the Madison Embedded Systems and Architectures Group. His research interests include high-performance embedded processors, computer architecture, domain-specific systems, computer arithmetic, and wireless systems. He is a senior member of the IEEE and the IEEE Computer Society, and an associate editor for the IEEE Transactions on Computers and the Journal of VLSI Signal Processing. John Glossner is CTO & Executive Vice President at Sandbridge Technologies. Prior to co-founding Sandbridge, John managed the Advanced DSP Technology group, Broadband Transmission Systems group, and was Access Aggregation Business Development manager at IBM’s T.J. Watson Research Center. Prior to IBM, John managed the software effort in Lucent/Motorola’s Starcore DSP design center. John received a Ph.D. in Computer Architecture from TU Delft in the Netherlands for his work on a Multithreaded Java processor with DSP capability. He also received an M.S. degree in Engineering Management and an M.S.E.E. from NTU. John also holds a B.S.E.E. degree from Penn State. John has more than 60 publications and 12 issued patents. Dr. Sanjay Jinturkar is the Director of Software at Sandbridge and manages the systems software and communications software groups. Previously, he managed the software tools group at StarCore. He has a Ph.D in Computer Science from University of Virginia and holds 20 publications and 4 patents. Mayan Moudgill obtained a Ph.D. in Computer Science from Cornell University in 1994, after which he joined IBM at the Thomas J. Watson Research Center. He worked on a variety of computer architecture and compiler related projects, including the VLIW research compiler, Linux ports for the 40x series embedded processors and simulators for the Power 4. In 2001, he co-founded Sandbridge Technologies, a start-up that is developing digital signal processors targeted at 3G wireless phones. Suman Mamidi is a graduate student in the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison. He received his M.S. degree from the University of Wisconsin-Madison in December, 2003 and is currently working towards his PhD. His research interests include low-power processors, hardware accelerators, multithreaded processors, reconfigurable hardware, and embedded systems. Stamatis Vassiliadis was born in Manolates, Samos, Greece, in 1951. He is currently a Chair Professor in the Electrical Engineering, Mathematics, and Computer Science (EEMCS) department of Delft University of Technology (TU Delft), The Netherlands. He previously served in the Electrical and Computer Engineering faculties of Cornell University, Ithaca, NY and the State University of New York (S.U.N.Y.), Binghamton, NY. For a decade, he worked with IBM, where he was involved in a number of advanced research and development projects. He received numerous awards for his work, including 24 publication awards, 15 invention awards, and an outstanding innovation award for engineering/scientific hardware design. His 73 USA patents rank him as the top all time IBM inventor. Dr. Vassiliadis is an ACM fellow, an IEEE fellow and a member of the Royal Netherlands Academy of Arts and Sciences (KNAW).     

Stable and functional immobilization of histidine-tagged proteins via multivalent chelator headgroups on a molecular poly(ethylene glycol) brush

We present a generic approach for immobilizing oligohistidine-tagged proteins with high stability and homogeneous functionality onto glass-type surfaces. Multivalent chelator heads (MCH) carrying two and three nitrilotriacetic acid (NTA) moieties were coupled with controlled surface concentration to glass surfaces premodified with an ultrathin two-dimensional polymer brush of a bifunctional poly(ethylene glycol). Low roughness and lateral homogeneity of these surfaces were confirmed by AFM and fluorescence microscopy, respectively. Protein immobilization and interactions at these interfaces were studied by label-free and fluorescence detection. Oligohistidine-tagged proteins bound specifically to NTA loaded with nickel(II) ions and could be eluted with imidazole. More than 90% of the immobilized protein preserved its activity. In contrast to mono-NTA, immobilized multivalent chelator heads bound oligohistidine-tagged proteins stoichiometrically and with high stability, even at very low chelator surface concentrations. Thus, an excess of the metal chelator sites was not necessary, and excessive binding sites could be quantitatively blocked with an indifferent protein. As a consequence, increased functional stability of the immobilized protein and a substantial reduction in nonspecific adsorption were achieved. Binding of histidine-tagged proteins to the MCH-modified surface was efficiently blocked by stoichiometric amounts of soluble MCH, and biomolecular interaction unbiased by the interaction of the histidine tag to the surface-bound MCH was observed. These excellent features and the compatibility with many solid-phase analytical techniques make this surface chemistry beneficial for functional protein analysis.     

Heat transfer in an evaporating thin liquid film moving slowly along the walls of an inclined microchannel

A theoretical study has been undertaken to determine the rate of heat transfer in a thin evaporating liquid film flowing along the walls of a microchannel under the combined action of surface tension and gravity. Analytical solutions of conservation equations, in both liquid and vapour phases, have been obtained, in considerations with coupled heat and mass transfer boundary conditions at the interface. It has been recognized that while the local Nusselt number is influenced solely by the liquid film thickness, the average Nusselt number depends both on liquid film thickness and a dimensionless number ρgsinθ, as obtained from the scale of characteristic velocity for both gravity and surface tension.     

Myoglobin and lipid oxidation interactions: Mechanistic bases and control

Lipid oxidation and myoglobin oxidation in meat lead to off-flavor development and discoloration, respectively. These processes often appear to be linked and the oxidation of one of these leads to the formation of chemical species that can exacerbate oxidation of the other. Several investigators have reported preservation of fresh meat color following the inclusion of antioxidant ingredients. An understanding of the complementary oxidation interaction provides a basis for explaining quality deterioration in meat and also for developing strategies to maintain optimal sensory qualities.     

Acrylamide removal from heated foods

The possibility to remove acrylamide from foods by exploiting its chemical physical properties was studied. Commercial biscuits and potato chips were subjected to vacuum treatments at different combinations of pressure, temperature and time. Results showed that acrylamide removal was achieved only in samples previously hydrated at water activity values higher than 0.83, and that, a maximum of acrylamide removal was obtained between 5 and 15 min of vacuum treatment at 6.67 Pa and 60 °C. By applying these process conditions, it was possible to remove 43% and 18% acrylamide from the biscuits and the potato chips, respectively. It was hypothesised that the vacuum treatment could favour acrylamide formation by promoting the decarboxylation of the Schiff base, a key intermediate of acrylamide formation. Although further research is needed to find out for each food category the process conditions that can maximise acrylamide removal while minimising its formation as well as to evaluate the effects on the sensory properties, this technology would represent a promising and alternative strategy to mitigation interventions aimed at reducing acrylamide levels in foods.     

Synthesis,Mechanism, and Gas‐Sensing Application of Surfactant Tailored Tungsten Oxide Nanostructures

Widely applicable nonaqueous solution routes have been employed for the syntheses of crystalline nanostructured tungsten oxide particles from a tungsten hexachloride precursor. Here, a systematic study on the crystallization and assembly behavior of tungsten oxide products made by using the bioligand deferoxamine mesylate (DFOM) (product I ), the two chelating ligands hexadecyltrimethylammoniumbromide (CTAB) ( II ) and poly(alkylene oxide) block copolymer (Pluronic P123) ( III ) is presented. The mechanistic pathways for the material synthesis are also discussed in detail. The tungsten oxide nanomaterials and reaction solutions are characterized by Fourier transform IR, ¹H, and ¹³C NMR spectroscopies, powder X‐ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high‐resolution TEM, and selected‐area electron diffraction. The indexing of the line pattern suggests WO₃ is in its monoclinic structure with a = 0.7297 nm, b = 0.7539 nm, c = 0.7688 nm, and β‐i; = 90.91 °. The nanoparticles formed have various architectures, such as chromosomal shapes (product I ) and slates ( II ), which are quite different from the mesoporous one ( III ) that has internal pores or mesopores ranging from 5 to 15 nm. The nanoparticles obtained from all the synthetic procedures are in the range of 40–60 nm. The investigation of the gas‐sensing properties of these materials indicate that all the sensors have good baseline stability and the sensors fabricated from material III present very different response kinetics and different CO detection properties. The possibility of adjusting the morphology and by that tuning the gas‐sensing properties makes the preparation strategies used interesting candidates for fabricating gas‐sensing materials.     

Remarkable change in the broadband electrical behavior of poly(vinylidene fluoride)–multiwalled carbon nanotube nanocomposites with the use of different processing routes

Poly(vinylidene fluoride) (PVDF) nanocomposites have plenty of applications in the electronic realm. In this study, we produced nanocomposites based on PVDF and multiwalled carbon nanotubes (MWCNTs), with various MWCNT loadings, using three different processing routes: solution mixing, melt mixing, and electrospinning. The broadband electrical behavior of these nanocomposites was studied and compared via impedance spectroscopy. The morphologies of the nanocomposites were characterized by transmission electron microscopy and scanning electron microscopy. The results reveal that the electrical behaviors of the samples were completely different according to the processing route used. Solution mixing was the most suitable method for producing nanocomposites with the highest conductivities, at low MWCNT loadings, whereas electrospinning was the most suitable method for producing nanocomposites with the lowest dielectric permittivity. These differences were attributed to the different arrangements of the MWCNTs caused by the different processes. Although the solution-mixed samples exhibited long and twisted MWCNTs, the melt-mixed samples had shorter MWCNTs, and the electrospun samples had MWCNTs embedded and aligned inside the insulating polymer nanofibers. Thus, these results project a vast horizon for tailoring the structure and thereby the broadband electrical behavior of PVDF–MWCNT nanocomposites for different types of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47409.     

Investigation of thermal performance of SAC variables using fuzzy logic based expert system

The thermal performance of a solar air collector (SAC) is investigated experimentally under the different climatic conditions of north eastern India using fuzzy logic based expert system (FLES). The FLES based on subtractive clustering (SC) with the fuzzy logic method where here, SC is used for extraction of optimal fuzzy IF-THEN rules while a fuzzy logic is used for modeling of SAC variables. This work considered four input variables [like mass flow rate (m), collector tilt angles (θ), solar radiation (Q), temperature (T)] and the four output variables [i.e. efficiency (η), exergetic efficiency (η_II), temperature rise (∆T), and pressure drop (∆P)]. First, 272 trials of experimentation on SAC are performed by varying m from 0.0078 to 0.0118 kg/s and θ from 30 to 60°, whereas the variation of metrological data is obtained in different working days. Then modeling and parametric analysis is carried out for SAC. Experimental results reveal that the value of η increases with the increase in m, Q, T and θ up to 45°. The higher value of m results in a higher value of ∆P and that reduces the value of η_II. Also, FLES model provides comparable and acceptable values for SAC. At last, validation of the FLES model is done via published data to confirm the results.

     

Poly(N-vinylpyrrolidone)-stabilized colloidal graphene-reinforced poly(ethylene-co-methyl acrylate) to mitigate electromagnetic radiation pollution

Polymer Bulletin - Electrically conducting flexible polymeric nanocomposite has been fabricated through wet mixing method where conducting inclusion was acoustically exfoliated pristine graphene...