5,631 research outputs found
DPP-PMRF: Rethinking Optimization for a Probabilistic Graphical Model Using Data-Parallel Primitives
We present a new parallel algorithm for probabilistic graphical model
optimization. The algorithm relies on data-parallel primitives (DPPs), which
provide portable performance over hardware architecture. We evaluate results on
CPUs and GPUs for an image segmentation problem. Compared to a serial baseline,
we observe runtime speedups of up to 13X (CPU) and 44X (GPU). We also compare
our performance to a reference, OpenMP-based algorithm, and find speedups of up
to 7X (CPU).Comment: LDAV 2018, October 201
Plugging Side-Channel Leaks with Timing Information Flow Control
The cloud model's dependence on massive parallelism and resource sharing
exacerbates the security challenge of timing side-channels. Timing Information
Flow Control (TIFC) is a novel adaptation of IFC techniques that may offer a
way to reason about, and ultimately control, the flow of sensitive information
through systems via timing channels. With TIFC, objects such as files,
messages, and processes carry not just content labels describing the ownership
of the object's "bits," but also timing labels describing information contained
in timing events affecting the object, such as process creation/termination or
message reception. With two system design tools-deterministic execution and
pacing queues-TIFC enables the construction of "timing-hardened" cloud
infrastructure that permits statistical multiplexing, while aggregating and
rate-limiting timing information leakage between hosted computations.Comment: 5 pages, 3 figure
IAC level "O" program development
The current status of the IAC development activity is summarized. The listed prototype software and documentation was delivered, and details were planned for development of the level 1 operational system. The planned end product IAC is required to support LSST design analysis and performance evaluation, with emphasis on the coupling of required technical disciplines. The long term IAC effectively provides two distinct features: a specific set of analysis modules (thermal, structural, controls, antenna radiation performance and instrument optical performance) that will function together with the IAC supporting software in an integrated and user friendly manner; and a general framework whereby new analysis modules can readily be incorporated into IAC or be allowed to communicate with it
Specifications and programs for computer software validation
Three software products developed during the study are reported and include: (1) FORTRAN Automatic Code Evaluation System, (2) the Specification Language System, and (3) the Array Index Validation System
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
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