9,951 research outputs found
Current-mode piecewise-linear function generators
We present a systematic design technique for current-mode piecewise-linear (PWL) function generators. It uses two building blocks: a high-resolution current rectifier, and a programmable current amplifier. We show how to arrange these blocks to obtain basic non-linearities from which generic characteristics are built through aggregations. Measurements from a 1.0 /spl mu/m CMOS prototype chip show 10 pA resolution in the rectification operation and 0.6% non-linearity errors in the programmable scaling operation for 2 /spl mu/A input current range
A Hardware Generator of Multi-point Distributed Random Numbers for Monte Carlo Simulation
Monte Carlo simulation of weak approximations of stochastic differential equations constitutes an intensive computational task. In applications such as finance, for instance, to achieve "real time" execution, as often required, one needs highly efficient implementations of the multi-point distributed random number generator underlying the simulations. In this paper a fast and flexible dedicated hardware solution on a field programmable gate array is presented. A comparative performance analysis between a software-only and the proposed hardware solution demonstrates that the hardware solution is bottleneck-free, retains the flexibility of the software solution and significantly increases the computational efficiency. Moreover, simulations in applications such as economics, insurance, physics, population dynamics, epidemiology, structural mechanics, chemistry and biotechnology can benefit from the obtained speedup.random number generators; random bit generators; hardware implementation; field programmable gate arrays (FPGAs); Monte Carlo simulation; weak Taylor schemes; multi-point distributed random variables
Optimization of the operation of smart rural grids through a novel rnergy management system
The paper proposes an innovative Energy Management System (EMS) that optimizes the grid operation based on economic and technical criteria. The EMS inputs the demand and renewable generation forecasts, electricity prices and the status of the distributed storages through the network, and solves with an optimal quarter-hourly dispatch for controllable resources. The performance of the EMS is quantified through diverse proposed metrics. The analyses were based on a real rural grid from the European FP7 project Smart Rural Grid. The performance of the EMS has been evaluated through some scenarios varying the penetration of distributed generation. The obtained results demonstrate that the inclusion of the EMS from both a technical point of view and an economic perspective for the adopted grid is justified. At the technical level, the inclusion of the EMS permits us to significantly increase the power quality in weak and radial networks. At the economic level and from a certain threshold value in renewables’ penetration, the EMS reduces the energy costs for the grid participants, minimizing imports from the external grid and compensating the toll to be paid in the form of the losses incurred by including additional equipment in the network (i.e., distributed storage).Postprint (published version
Algebras and universal quantum computations with higher dimensional systems
Here is discussed application of the Weyl pair to construction of universal
set of quantum gates for high-dimensional quantum system. An application of Lie
algebras (Hamiltonians) for construction of universal gates is revisited first.
It is shown next, how for quantum computation with qubits can be used
two-dimensional analog of this Cayley-Weyl matrix algebras, i.e. Clifford
algebras, and discussed well known applications to product operator formalism
in NMR, Jordan-Wigner construction in fermionic quantum computations. It is
introduced universal set of quantum gates for higher dimensional system
(``qudit''), as some generalization of these models. Finally it is briefly
mentioned possible application of such algebraic methods to design of quantum
processors (programmable gates arrays) and discussed generalization to quantum
computation with continuous variables.Comment: 12 pages, LaTeXe, Was prepared for QI2002, Moscow, 1-4.1
PGPG: An Automatic Generator of Pipeline Design for Programmable GRAPE Systems
We have developed PGPG (Pipeline Generator for Programmable GRAPE), a
software which generates the low-level design of the pipeline processor and
communication software for FPGA-based computing engines (FBCEs). An FBCE
typically consists of one or multiple FPGA (Field-Programmable Gate Array)
chips and local memory. Here, the term "Field-Programmable" means that one can
rewrite the logic implemented to the chip after the hardware is completed, and
therefore a single FBCE can be used for calculation of various functions, for
example pipeline processors for gravity, SPH interaction, or image processing.
The main problem with FBCEs is that the user need to develop the detailed
hardware design for the processor to be implemented to FPGA chips. In addition,
she or he has to write the control logic for the processor, communication and
data conversion library on the host processor, and application program which
uses the developed processor. These require detailed knowledge of hardware
design, a hardware description language such as VHDL, the operating system and
the application, and amount of human work is huge. A relatively simple design
would require 1 person-year or more. The PGPG software generates all necessary
design descriptions, except for the application software itself, from a
high-level design description of the pipeline processor in the PGPG language.
The PGPG language is a simple language, specialized to the description of
pipeline processors. Thus, the design of pipeline processor in PGPG language is
much easier than the traditional design. For real applications such as the
pipeline for gravitational interaction, the pipeline processor generated by
PGPG achieved the performance similar to that of hand-written code. In this
paper we present a detailed description of PGPG version 1.0.Comment: 24 pages, 6 figures, accepted PASJ 2005 July 2
Synthesis of anisotropic swirling surface acoustic waves by inverse filter, towards integrated generators of acoustical vortices
From radio-electronics signal analysis to biological samples actuation,
surface acoustic waves (SAW) are involved in a multitude of modern devices.
Despite this versatility, SAW transducers developed up to date only authorize
the synthesis of the most simple standing or progressive waves such as plane
and focused waves. In particular, acoustical integrated sources able to
generate acoustical vortices (the analogue of optical vortices) are missing. In
this work, we propose a flexible tool based on inverse filter technique and
arrays of SAW transducers enabling the synthesis of prescribed complex wave
patterns at the surface of anisotropic media. The potential of this setup is
illustrated by the synthesis of a 2D analog of 3D acoustical vortices, namely
"swirling surface acoustic waves". Similarly to their 3D counterpart, they
appear as concentric structures of bright rings with a phase singularity in
their center resulting in a central dark spot. Swirling SAW can be useful in
fragile sensors whose neighborhood needs vigorous actuation, and may also serve
as integrated transducers for acoustical vortices. Since these waves are
essential to fine acoustical tweezing, swirling SAW may become the cornerstone
of future micrometric devices for contactless manipulation
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