119,384 research outputs found
A Logic Simplification Approach for Very Large Scale Crosstalk Circuit Designs
Crosstalk computing, involving engineered interference between nanoscale
metal lines, offers a fresh perspective to scaling through co-existence with
CMOS. Through capacitive manipulations and innovative circuit style, not only
primitive gates can be implemented, but custom logic cells such as an Adder,
Subtractor can be implemented with huge gains. Our simulations show over 5x
density and 2x power benefits over CMOS custom designs at 16nm [1]. This paper
introduces the Crosstalk circuit style and a key method for large-scale circuit
synthesis utilizing existing EDA tool flow. We propose to manipulate the CMOS
synthesis flow by adding two extra steps: conversion of the gate-level netlist
to Crosstalk implementation friendly netlist through logic simplification and
Crosstalk gate mapping, and the inclusion of custom cell libraries for
automated placement and layout. Our logic simplification approach first
converts Cadence generated structured netlist to Boolean expressions and then
uses the majority synthesis tool to obtain majority functions, which is further
used to simplify functions for Crosstalk friendly implementations. We compare
our approach of logic simplification to that of CMOS and majority logic-based
approaches. Crosstalk circuits share some similarities to majority synthesis
that are typically applied to Quantum Cellular Automata technology. However,
our investigation shows that by closely following Crosstalk's core circuit
styles, most benefits can be achieved. In the best case, our approach shows 36%
density improvements over majority synthesis for MCNC benchmark
A debugging model for functional logic programs
This paper presents a box-oriented debugging model for the functional logic language ALF. Due to the sophisticated operational semantics of ALF which is based on innermost basic narrowing with simplification, the debugger must reflect the application of the different computation rules during program execution. Hence our debugging model includes not only one box type as in Byrd's debugging model for logic programs but several different kinds of boxes corresponding to the various computation rules of the functional logic language (narrowing, simplification etc.). Moreover, additional box types are introduced in order to allow skips over (sometimes) uninteresting program parts like proofs of the condition in a conditional equation. Since ALF is a genuine amalgamation of functional and logic languages, our debugging model subsumes operational aspects of both kinds of languages. As a consequence, it can be also used for pure logic languages, pure functional languages with eager evaluation, or functional logic languages with a less sophisticated operational semantics like SLOG or eager BABEL
Dynamic resource management in SDN-based virtualized networks
Network virtualization allows for an abstraction between user and physical resources by letting a given physical infrastructure to be shared by multiple service providers. However, network virtualization presents some challenges, such as, efficient resource management, fast provisioning and scalability. By separating a network's control logic from the underlying routers and switches, software defined networking (SDN) promises an unprecedented simplification in network programmability, management and innovation by service providers, and hence, its control model presents itself as a candidate solution to the challenges in network virtualization. In this paper, we use the SDN control plane to efficiently manage resources in virtualized networks by dynamically adjusting the virtual network (VN) to substrate network (SN) mappings based on network status. We extend an SDN controller to monitor the resource utilisation of VNs, as well as the average loading of SN links and switches, and use this information to proactively add or remove flow rules from the switches. Simulations show that, compared with three state-of-art approaches, our proposal improves the VN acceptance ratio by about 40% and reduces VN resource costs by over 10%
On Various Negative Translations
Several proof translations of classical mathematics into intuitionistic
mathematics have been proposed in the literature over the past century. These
are normally referred to as negative translations or double-negation
translations. Among those, the most commonly cited are translations due to
Kolmogorov, Godel, Gentzen, Kuroda and Krivine (in chronological order). In
this paper we propose a framework for explaining how these different
translations are related to each other. More precisely, we define a notion of a
(modular) simplification starting from Kolmogorov translation, which leads to a
partial order between different negative translations. In this derived
ordering, Kuroda and Krivine are minimal elements. Two new minimal translations
are introduced, with Godel and Gentzen translations sitting in between
Kolmogorov and one of these new translations.Comment: In Proceedings CL&C 2010, arXiv:1101.520
Automatic Generation of CHR Constraint Solvers
In this paper, we present a framework for automatic generation of CHR solvers
given the logical specification of the constraints. This approach takes
advantage of the power of tabled resolution for constraint logic programming,
in order to check the validity of the rules. Compared to previous works where
different methods for automatic generation of constraint solvers have been
proposed, our approach enables the generation of more expressive rules (even
recursive and splitting rules) that can be used directly as CHR solvers.Comment: to be published in Theory and Practice of Logic Programming, 16
pages, 2 figure
(Co-)Inductive semantics for Constraint Handling Rules
In this paper, we address the problem of defining a fixpoint semantics for
Constraint Handling Rules (CHR) that captures the behavior of both
simplification and propagation rules in a sound and complete way with respect
to their declarative semantics. Firstly, we show that the logical reading of
states with respect to a set of simplification rules can be characterized by a
least fixpoint over the transition system generated by the abstract operational
semantics of CHR. Similarly, we demonstrate that the logical reading of states
with respect to a set of propagation rules can be characterized by a greatest
fixpoint. Then, in order to take advantage of both types of rules without
losing fixpoint characterization, we present an operational semantics with
persistent. We finally establish that this semantics can be characterized by
two nested fixpoints, and we show the resulting language is an elegant
framework to program using coinductive reasoning.Comment: 17 page
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