76,960 research outputs found
Timing verification of dynamically reconfigurable logic for Xilinx Virtex FPGA series
This paper reports on a method for extending existing VHDL design and verification software available for the Xilinx Virtex series of FPGAs. It allows the designer to apply standard hardware design and verification tools to the design of dynamically reconfigurable logic (DRL). The technique involves the conversion of a dynamic design into multiple static designs, suitable for input to standard synthesis and APR tools. For timing and functional verification after APR, the sections of the design can then be recombined into a single dynamic system. The technique has been automated by extending an existing DRL design tool named DCSTech, which is part of the Dynamic Circuit Switching (DCS) CAD framework. The principles behind the tools are generic and should be readily extensible to other architectures and CAD toolsets. Implementation of the dynamic system involves the production of partial configuration bitstreams to load sections of circuitry. The process of creating such bitstreams, the final stage of our design flow, is summarized
Runtime Verification Based on Executable Models: On-the-Fly Matching of Timed Traces
Runtime verification is checking whether a system execution satisfies or
violates a given correctness property. A procedure that automatically, and
typically on the fly, verifies conformance of the system's behavior to the
specified property is called a monitor. Nowadays, a variety of formalisms are
used to express properties on observed behavior of computer systems, and a lot
of methods have been proposed to construct monitors. However, it is a frequent
situation when advanced formalisms and methods are not needed, because an
executable model of the system is available. The original purpose and structure
of the model are out of importance; rather what is required is that the system
and its model have similar sets of interfaces. In this case, monitoring is
carried out as follows. Two "black boxes", the system and its reference model,
are executed in parallel and stimulated with the same input sequences; the
monitor dynamically captures their output traces and tries to match them. The
main problem is that a model is usually more abstract than the real system,
both in terms of functionality and timing. Therefore, trace-to-trace matching
is not straightforward and allows the system to produce events in different
order or even miss some of them. The paper studies on-the-fly conformance
relations for timed systems (i.e., systems whose inputs and outputs are
distributed along the time axis). It also suggests a practice-oriented
methodology for creating and configuring monitors for timed systems based on
executable models. The methodology has been successfully applied to a number of
industrial projects of simulation-based hardware verification.Comment: In Proceedings MBT 2013, arXiv:1303.037
RTL2RTL Formal Equivalence: Boosting the Design Confidence
Increasing design complexity driven by feature and performance requirements
and the Time to Market (TTM) constraints force a faster design and validation
closure. This in turn enforces novel ways of identifying and debugging
behavioral inconsistencies early in the design cycle. Addition of incremental
features and timing fixes may alter the legacy design behavior and would
inadvertently result in undesirable bugs. The most common method of verifying
the correctness of the changed design is to run a dynamic regression test suite
before and after the intended changes and compare the results, a method which
is not exhaustive. Modern Formal Verification (FV) techniques involving new
methods of proving Sequential Hardware Equivalence enabled a new set of
solutions for the given problem, with complete coverage guarantee. Formal
Equivalence can be applied for proving functional integrity after design
changes resulting from a wide variety of reasons, ranging from simple pipeline
optimizations to complex logic redistributions. We present here our experience
of successfully applying the RTL to RTL (RTL2RTL) Formal Verification across a
wide spectrum of problems on a Graphics design. The RTL2RTL FV enabled checking
the design sanity in a very short time, thus enabling faster and safer design
churn. The techniques presented in this paper are applicable to any complex
hardware design.Comment: In Proceedings FSFMA 2014, arXiv:1407.195
An analysis of spacecraft data time tagging errors
An indepth examination of the timing and telemetry in just one spacecraft points out the genesis of various types of timing errors and serves as a guide in the design of future timing/telemetry systems. The principal sources of timing errors are examined carefully and are described in detail. Estimates of these errors are also made and presented. It is found that the timing errors within the telemetry system are larger than the total timing errors resulting from all other sources
Informational Barriers to Energy Efficiency – Theory and European Policies
This BEER addresses informational barriers to energy efficiency. It is a widely acknowledged result that an energy efficiency gap exists implying that the level of energy efficiency is at an inefficiently low level. Several barriers to energy efficiency create this gap and the presence of asymmetric information is likely to be one such barrier. In this article a theoretical framework is presented addressing the issues of moral hazard and adverse selection related to energy efficiency. Based on the theoretical framework, European policies on energy efficiency are evaluated. The article is divided into two main parts. The first part presents the theory on information asymmetries and its consequences on energy efficiency focusing on the problems of moral hazard and adverse selection. Having established a theoretical framework to understand the agency barriers to energy efficiency, the second part evaluates the policies of the European Union on energy efficiency. The BEER finds that problems of moral hazard and adverse selection indeed can help explain the seemingly low levels of energy. In both presented models the cost to the principal from implementing high energy efficiency outcome is increased with the informational asymmetries. The theory reveals two implications to policies on energy efficiency. First, the development of measures to enable contractual parties to base remuneration on energy performance must be enhanced, and second, the information on technologies and the education of consumers and installers on energy efficiency must be increased. This could be complemented with certification of installers and energy efficiency advisors to enable consumers to select good agents. Finally, it is found that the preferred EU policy instrument on energy efficiency, so far, seems to be the use of minimum requirements. Less used in EU legislation is the use of measuring and verification as well as the use of certifications. Therefore, it is concluded that the EU should consider an increased use of these instruments, and in particular focus on a further development of standards on measurability and verification as well as an increased focus on education of consumers as well as installers and advisors on energy efficiency.Energy efficiency, Informational barriers, European policies
An Entry Point for Formal Methods: Specification and Analysis of Event Logs
Formal specification languages have long languished, due to the grave
scalability problems faced by complete verification methods. Runtime
verification promises to use formal specifications to automate part of the more
scalable art of testing, but has not been widely applied to real systems, and
often falters due to the cost and complexity of instrumentation for online
monitoring. In this paper we discuss work in progress to apply an event-based
specification system to the logging mechanism of the Mars Science Laboratory
mission at JPL. By focusing on log analysis, we exploit the "instrumentation"
already implemented and required for communicating with the spacecraft. We
argue that this work both shows a practical method for using formal
specifications in testing and opens interesting research avenues, including a
challenging specification learning problem
IMITATOR II: A Tool for Solving the Good Parameters Problem in Timed Automata
We present here Imitator II, a new version of Imitator, a tool implementing
the "inverse method" for parametric timed automata: given a reference valuation
of the parameters, it synthesizes a constraint such that, for any valuation
satisfying this constraint, the system behaves the same as under the reference
valuation in terms of traces, i.e., alternating sequences of locations and
actions. Imitator II also implements the "behavioral cartography algorithm",
allowing us to solve the following good parameters problem: find a set of
valuations within a given bounded parametric domain for which the system
behaves well. We present new features and optimizations of the tool, and give
results of applications to various examples of asynchronous circuits and
communication protocols.Comment: In Proceedings INFINITY 2010, arXiv:1010.611
Side-channel based intrusion detection for industrial control systems
Industrial Control Systems are under increased scrutiny. Their security is
historically sub-par, and although measures are being taken by the
manufacturers to remedy this, the large installed base of legacy systems cannot
easily be updated with state-of-the-art security measures. We propose a system
that uses electromagnetic side-channel measurements to detect behavioural
changes of the software running on industrial control systems. To demonstrate
the feasibility of this method, we show it is possible to profile and
distinguish between even small changes in programs on Siemens S7-317 PLCs,
using methods from cryptographic side-channel analysis.Comment: 12 pages, 7 figures. For associated code, see
https://polvanaubel.com/research/em-ics/code
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