3,676 research outputs found
Finite State Machines With Input Multiplexing: A Performance Study
Finite state machines with input multiplexing (FSMIMs)
have been proposed in previous works as a technique for efficient
mapping FSMs into ROM memory. In this paper, we propose a new
architecture for implementing FSMIMs, called FSMIM with state-based
input selection, whose goal is to achieve a further reduction in memory
usage. This paper also describes in detail the algorithms for generating
FSMIMs used by the tool FSMIM-Gen, which has been developed
and made available on the Internet for free public use. A comparative
study in terms of speed and area between FSMIM approaches
and other field programmable gate array-based techniques is presented.
The results show that the FSMIM approaches obtain huge
reductions in the look-up table (LUT) usage by using a small number
of embedded memory blocks. In addition, speed improvements
over conventional LUT-based implementations have been obtained in
many cases
An FSM Re-Engineering Approach to Sequential Circuit Synthesis by State Splitting
We propose Finite State Machine (FSM) re-engineering, a
performance enhancement framework for FSM synthesis and
optimization. It starts with the traditional FSM synthesis procedure,
then proceeds to re-construct a functionally equivalent
but topologically different FSM based on the optimization
objective, and concludes with another round of FSM synthesis
on the re-constructed FSM. This approach explores a larger
solution space that consists of a set of FSMs functionally
equivalent to the original one, making it possible to obtain
better solutions than in the original FSM. Guided by the result
from the #2;rst round of synthesis, the solution space exploration
process can be rapid and cost-ef#2;cient.
We apply this framework to FSM state encoding for power
minimization and area minimization. The FSM is #2;rst minimized
and encoded using existing state encoding algorithms.
Then we develop both a heuristic algorithm and a genetic
algorithm to re-construct the FSM. Finally, the FSM is reencoded
by the same encoding algorithms. To demonstrate
the effectiveness of this framework, we conduct experiments
on MCNC91 sequential circuit benchmarks. The circuits are
read in and synthesized in SIS environment. After FSM
re-engineering are performed, we measure the power, area
and delay in the newly synthesized circuits. In the powerdriven
synthesis, we observe an average 5.5% of total power
reduction with 1.3% area increase and 1.3% delay increase.
This results are in general better than other low power state
encoding techniques on comparable cases. In the area-driven
synthesis, we observe an average 2.7% area reduction, 1.8%
delay reduction, and 0.4% power increase. Finally, we use
integer linear programming to obtain the optimal low power
state encoding for benchmarks of small size. We #2;nd that the
optimal solutions in the re- engineered FSMs are 1% to 8%
better than the optimal solutions in the original FSMs in terms
of power minimization
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Oracles for distributed testing
Copyright @ 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.The problem of deciding whether an observed behaviour is acceptable is the oracle problem. When testing from a finite state machine (FSM) it is easy to solve the oracle problem and so it has received relatively little attention for FSMs. However, if the system under test has physically distributed interfaces, called ports, then in distributed testing we observe a local trace at each port and we compare the set of local traces with the set of allowed behaviours (global traces). This paper investigates the oracle problem for deterministic and non-deterministic FSMs and for two alternative definitions of conformance for distributed testing. We show that the oracle problem can be solved in polynomial time for the weaker notion of conformance but is NP-hard for the stronger notion of conformance, even if the FSM is deterministic. However, when testing from a deterministic FSM with controllable input sequences the oracle problem can be solved in polynomial time and similar results hold for nondeterministic FSMs. Thus, in some cases the oracle problem can be efficiently
solved when using stronger notion of conformance and where this is not the case we can use the decision procedure for weaker notion of conformance as a sound approximation
An integrated search-based approach for automatic testing from extended finite state machine (EFSM) models
This is the post-print version of the Article - Copyright @ 2011 ElsevierThe extended finite state machine (EFSM) is a modelling approach that has been used to represent a wide range of systems. When testing from an EFSM, it is normal to use a test criterion such as transition coverage. Such test criteria are often expressed in terms of transition paths (TPs) through an EFSM. Despite the popularity of EFSMs, testing from an EFSM is difficult for two main reasons: path feasibility and path input sequence generation. The path feasibility problem concerns generating paths that are feasible whereas the path input sequence generation problem is to find an input sequence that can traverse a feasible path. While search-based approaches have been used in test automation, there has been relatively little work that uses them when testing from an EFSM. In this paper, we propose an integrated search-based approach to automate testing from an EFSM. The approach has two phases, the aim of the first phase being to produce a feasible TP (FTP) while the second phase searches for an input sequence to trigger this TP. The first phase uses a Genetic Algorithm whose fitness function is a TP feasibility metric based on dataflow dependence. The second phase uses a Genetic Algorithm whose fitness function is based on a combination of a branch distance function and approach level. Experimental results using five EFSMs found the first phase to be effective in generating FTPs with a success rate of approximately 96.6%. Furthermore, the proposed input sequence generator could trigger all the generated feasible TPs (success rate = 100%). The results derived from the experiment demonstrate that the proposed approach is effective in automating testing from an EFSM
Dynamic load balancing for the distributed mining of molecular structures
In molecular biology, it is often desirable to find common properties in large numbers of drug candidates. One family of
methods stems from the data mining community, where algorithms to find frequent graphs have received increasing attention over the
past years. However, the computational complexity of the underlying problem and the large amount of data to be explored essentially
render sequential algorithms useless. In this paper, we present a distributed approach to the frequent subgraph mining problem to
discover interesting patterns in molecular compounds. This problem is characterized by a highly irregular search tree, whereby no
reliable workload prediction is available. We describe the three main aspects of the proposed distributed algorithm, namely, a dynamic
partitioning of the search space, a distribution process based on a peer-to-peer communication framework, and a novel receiverinitiated
load balancing algorithm. The effectiveness of the distributed method has been evaluated on the well-known National Cancer
Institute’s HIV-screening data set, where we were able to show close-to linear speedup in a network of workstations. The proposed
approach also allows for dynamic resource aggregation in a non dedicated computational environment. These features make it suitable
for large-scale, multi-domain, heterogeneous environments, such as computational grids
Enhancing Power Efficient Design Techniques in Deep Submicron Era
Excessive power dissipation has been one of the major bottlenecks for design and
manufacture in the past couple of decades. Power efficient design has become
more and more challenging when technology scales down to the deep submicron era
that features the dominance of leakage, the manufacture variation, the on-chip
temperature variation and higher reliability requirements, among others. Most of the computer aided design (CAD) tools and algorithms currently used in industry
were developed in the pre deep submicron era and did not consider the new features explicitly and adequately.
Recent research advances in deep submicron design, such as the mechanisms of leakage, the source and characterization of manufacture variation, the cause and
models of on-chip temperature variation, provide us the opportunity to incorporate these important issues in power efficient design. We explore this opportunity in this dissertation by demonstrating that significant power reduction can be achieved with only minor modification to the existing CAD tools and algorithms.
First, we consider peak current, which has become critical for circuit's reliability in deep submicron design. Traditional low power design techniques focus on
the reduction of average power. We propose to reduce peak current while keeping the overhead on average power as small as possible. Second, dual Vt technique and gate sizing have been used simultaneously for leakage savings. However, this approach becomes less effective in deep submicron design. We propose to use the newly developed process-induced mechanical stress to enhance its performance.
Finally, in deep submicron design, the impact of on-chip temperature variation on leakage and performance becomes more and more significant. We propose a temperature-aware dual Vt approach to alleviate hot spots and achieve further leakage reduction. We also consider this leakage-temperature dependency in the dynamic voltage scaling approach and discover that a commonly accepted result is incorrect for the current technology.
We conduct extensive experiments with popular design benchmarks, using the latest industry CAD tools and design libraries. The results show that our proposed enhancements are promising in power saving and are practical to solve the low power design challenges in deep submicron era
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