New access modes of parallel memory subsystem for sub-pixel motion estimation

Accessing pixels in memory is a well-known bottleneck of SIMD (single instruction multiple data) processors in video/imaging. To tackle it, we propose new block and row access modes of parallel on-chip memory subsystem, which enable a higher processing throughput and lower energy consumption than the access modes of the state-of-the-art subsystems. The new access modes significantly reduce the number of on-chip memory accesses, and thereby accelerate one of key video/imaging kernels: sub-pixel block-matching motion estimation. The main idea is to exploit spatial overlaps of blocks/rows accessed for pixel interpolation, which are known at the subsystem design-time, and merge multiple accesses into a single one by accessing somewhat more pixels at a time than with other parallel memories. To avoid the need for a wider, and, therefore, more costly SIMD datapath, we propose new memory read operations that split all pixels accessed at a time into multiple SIMD-wide blocks/rows, in a convenient way for further processing. As a proof of concept, we describe a parametric, scalable, and cost-efficient architecture that supports the new access modes. The architecture is based on a previously proposed set of memory banks with multiple pixels per bank word, and a previously proposed shifted scheme for arranging pixels in the banks. We analytically and experimentally demonstrate advantages of this work on a case study of sub-pixel motion estimation for video frame-rate conversion. The implemented motion estimator processes 2160p video at 60 fps in real time, while clocked at 600 MHz. Compared to the implementations based on the state-of-the-art subsystems, this work enables 40–70 % higher throughput, consumes 17–44 % less energy and has similar silicon area and off-chip memory bandwidth costs. That is 1.8–2.9 times more efficient than the prior art, considering the throughput and all costs, i.e., consumption, area, and off-chip bandwidth. Such a higher efficiency is the result of the new access modes, which reduced the number of on-chip memory accesses by 1.6–2.1 times, and the cost-efficient architecture.     

An Approximation Framework for Solvers and Decision Procedures

We consider the problem of automatically and efficiently computing models of constraints, in the presence of complex background theories such as floating-point arithmetic. Constructing models, or proving that a constraint is unsatisfiable, has various applications, for instance for automatic generation of test inputs. It is well-known that a naïve encoding of constraints into simpler theories (for instance, bit-vectors or propositional logic) often leads to a drastic increase in size, or that it is unsatisfactory in terms of the resulting space and runtime demands. We define a framework for systematic application of approximations in order to improve performance. Our method is more general than previous techniques in the sense that approximations that are neither under- nor over-approximations can be used, and it shows promising performance on practically relevant benchmark problems.     

Thermodynamic modeling of vapor-liquid equilibria and excess properties of the binary systems containing diethers and n-alkanes by cubic equation of state

A comparison of the performances of two different approaches of cubic equations of state models, based on a classical van der Waals and mixing rules incorporating theG ^E equation, was carried out for correlation of Vapor-Liquid Equilibria (VLE), H^E and C _P ^E data alone, and simultaneous correlation of VLE+H^E, VLE+C _P ^E , H^E +C _P ^E and VLE+H^E +C _P ^E data for the diethers (1,4-dioxane or 1,3-dioxolane) with n-alkane systems. For all calculations the Peng-Robinson-Stryjek-Vera cubic equation of state (PRSV CEOS) was used. A family of mixing rules for the PRSV CEOS based on the Modified van der Waals one-fluid mixing rule (MvdW1) and two well-known CEOS/G^E mixing rules (MHV1 and MHV2), was considered. The NRTL equation, as the G^E model with linear or reciprocal temperature dependent parameters, was incorporated in the CEOS/G^E models. The results obtained by the CEOS/G^E models exhibit significant improvement in comparison to the MvdW1 models.     

A new method in designing compatibility and adhesion of EVA/PMMA blend by using EVA-<Emphasis Type="Italic">g</Emphasis>-PMMA with controlled graft chain length

Atom transfer free radical polymerization (ATRP) was employed in a synthesis of graft polymer EVA-g-PMMA with controlled length of side PMMA chains. Three steps of synthesis: partial hydrolysis of EVA, esterification with chloroacetyl chloride and ATRP grafting were performed to produce EVAOH, macroinitiator EVACl and grafted polymers G8020 (EVA/PMMA?=?80/20 wt%) and G6040 (EVA/PMMA?=?60/40 wt%). FTIR, Raman and NMR spectroscopy were used in the determination of the chemical structure and modification of EVA. Transmitted light and dark field microscopy showed higher affinity for coil formation of EVA-g-PMMA with longer PMMA side chains, i.e. G6040 compatibilizer. Morphological, thermal and adhesive properties of optical fiber adhesives of graft polymers and polymer blends poly(ethylene-co-vinyl acetate)-blend-poly(methyl methacrylate) (EVA/PMMA) compatibilized with 1 wt% of EVA-g-PMMA, were studied. Image analysis of SEM micrographs showed effective compatibilization with short grafted chains (G8020) that was indicated by lower porosity characteristics. TG/DTG analysis enabled determination of degree of hydrolysis and amount of chloro-functionalized groups. DSC analysis showed higher thermal stability of G8020 polymer. Single lap joint of adhesives/optical fibers were subjected to adhesive testing and obtained results for maximal force applied and adhesive failure suggested the visible influence of the length of graft chains on adhesion.     

Microstructural and Tribological Properties of A356 Al–Si Alloy Reinforced with Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Particles

In the present study, the effect of the Al₂O₃ particles (average size of 12 μm, 3 and 10 wt.%) reinforcement on the microstructure and tribological properties of Al–Si alloy (A356) was investigated. Composites were produced by applying compocasting process. Tribological properties of unreinforced alloy and composites were studied, using pin-on-disc tribometer, under dry sliding conditions at different specific loads and sliding speed of 1 m/s. Microhardness measurements, optical microscope and scanning electron microscope were used for microstructural characterization and investigation of worn surfaces and wear debris. During compocasting of A356 alloy, a transformation from a typical dendritic primary α phase to a non-dendritic rosette-like structure occurred. Composites exhibited better wear resistance compared with unreinforced alloy. Presence of 3 wt.% Al₂O₃ particles in the composite material affected the wear resistance only at specific loads up to 1 MPa. The wear rate of composite with 10 wt.% Al₂O₃ particles was nearly two order of the magnitude lower than the wear rate of the matrix alloy. Dominant wear mechanism for all materials was adhesion, with others mechanisms: oxidation, abrasion and delamination as minor ones.     

Marginal adaptation of composite resins under two adhesive techniques

In the present research, different adhesive techniques were used to set up fillings with composite resins. After the application of etch and rinse or self etch adhesive technique, marginal adaptation of composite fillings was estimated by the length of margins without gaps, and by the microretention of resin in enamel and dentin. The study material consisted of 40 extracted teeth. Twenty Class V cavities were treated with 35% phosphorous acid and restored after rinsing by Adper Single Bond 2 and Filtek Ultimate‐ASB/FU 3M ESPE composite system. The remaining 20 cavities were restored by Adper Easy One‐AEO/FU 3M ESPE composite system. Marginal adaptation of composite fillings was examined using a scanning electron microscope (SEM). The etch and rinse adhesive technique showed a significantly higher percentage of margin length without gaps (in enamel: 92.5%, in dentin: 57.3%), compared with the self‐etch technique with lower percentage of margin length without gaps, in enamel 70.4% (p < .001), and in dentin‐22.6% (p < .05). In the first technique, microretention was composed of adhesive and hybrid layers as well as resin tugs in interprismatic spaces of enamel, while the dentin microretention was composed of adhesive and hybrid layers with resin tugs in dentin canals. In the second technique, resin tugs were rarely seen and a microgap was dominant along the border of restoration margins. The SEM analysis showed a better marginal adaptation of composite resin to enamel and dentin with better microretention when the etch and rinse adhesive procedure was applied.     

Linearisation of asymmetrical Doherty amplifier by the even-order non-linear signals

This paper considers the linearisation of an asymmetrical two-way Doherty amplifier by the method that uses the second harmonics and fourth-order non-linear signals for linearisation. These even-order signals for linearisation are extracted at the output of the peaking amplifier, adjusted in amplitude and phase and injected at the input and output of the carrier amplifier transistor in the Doherty configuration. The effect of linearisation has been experimentally confirmed on a fabricated asymmetrical Doherty amplifier with the additional circuit for linearisation. The suppression of the third-order intermodulation products has been carried out for two-tone test, 64QAM and WCDMA digitally modulated signals in a range of signal power.     

Generalized charge simulation method for the calculation of the electric field in high voltage substations

This paper deals with the calculation of the electric field strength in high voltage (HV) substations comprising complex geometrical structures. Generalized charge simulation method is proposed for improving the precision of the calculation of the electric field strength. The objective of this analysis is to examine the influence of towers, HV apparatus and fences on the spatial electric field distribution. For this purpose, a three-dimensional generalized model of HV substation has been developed, including phase conductors, bypass busbars, HV apparatus, fences and towers (denoted as Full model). The obtained results of the calculation of the electric field strength are compared with the Simplified model, which only includes phase conductors connected to HV network. Verification of the proposed Full model performed by comparing the calculated and in-field measured values of the electric field strength within HV substations and in their vicinity gives very promising results.     

Reliability of AlN substrates and their solder joints in IGBT power modules

The reliability of IGBT modules was investigated with respect to the metallized ceramic (substrate) and the solder layer between the substrate and copper baseplate. Thermal cycles were performed between −55°C and +150°C on substrates based on different technologies and from various manufacturers. An incipient delamination of the metallization could be predicted from the mechanical resonance frequency. The warping of the substrates after cycling due to crack propagation and the adhesion of the metallization were determined. Thermal and active-power cycles were performed on 1200 A / 3.3 kV IGBT power modules to investigate the reliability of the solder joint between substrate and baseplate.     

Photo-catalytic properties of silicon and its future in photovoltaic applications

With the possible depletion of fossil fuels in just one generation and the risk of eventual nuclear incidents, the question is whether renewable energy sources have the capacity to replace traditional ones. The availability of solar energy is significantly higher than any other renewable source and silicon is currently the major photo-catalytic material in the solar industry. Conversion efficiency and payback time are noted as key factors, besides atmospheric imperviousness, all of which affect usability of photo-catalytic material. The status and future of Si as a major candidate to take over from traditional sources of energy relies on cost reduction of the high purity Si used as feedstock for solar cell industry, reduced installation costs and network maintenance and development of the next generation of Si solar cells.