42,019 research outputs found
AutoAccel: Automated Accelerator Generation and Optimization with Composable, Parallel and Pipeline Architecture
CPU-FPGA heterogeneous architectures are attracting ever-increasing attention
in an attempt to advance computational capabilities and energy efficiency in
today's datacenters. These architectures provide programmers with the ability
to reprogram the FPGAs for flexible acceleration of many workloads.
Nonetheless, this advantage is often overshadowed by the poor programmability
of FPGAs whose programming is conventionally a RTL design practice. Although
recent advances in high-level synthesis (HLS) significantly improve the FPGA
programmability, it still leaves programmers facing the challenge of
identifying the optimal design configuration in a tremendous design space.
This paper aims to address this challenge and pave the path from software
programs towards high-quality FPGA accelerators. Specifically, we first propose
the composable, parallel and pipeline (CPP) microarchitecture as a template of
accelerator designs. Such a well-defined template is able to support efficient
accelerator designs for a broad class of computation kernels, and more
importantly, drastically reduce the design space. Also, we introduce an
analytical model to capture the performance and resource trade-offs among
different design configurations of the CPP microarchitecture, which lays the
foundation for fast design space exploration. On top of the CPP
microarchitecture and its analytical model, we develop the AutoAccel framework
to make the entire accelerator generation automated. AutoAccel accepts a
software program as an input and performs a series of code transformations
based on the result of the analytical-model-based design space exploration to
construct the desired CPP microarchitecture. Our experiments show that the
AutoAccel-generated accelerators outperform their corresponding software
implementations by an average of 72x for a broad class of computation kernels
A Multi-view Context-aware Approach to Android Malware Detection and Malicious Code Localization
Existing Android malware detection approaches use a variety of features such
as security sensitive APIs, system calls, control-flow structures and
information flows in conjunction with Machine Learning classifiers to achieve
accurate detection. Each of these feature sets provides a unique semantic
perspective (or view) of apps' behaviours with inherent strengths and
limitations. Meaning, some views are more amenable to detect certain attacks
but may not be suitable to characterise several other attacks. Most of the
existing malware detection approaches use only one (or a selected few) of the
aforementioned feature sets which prevent them from detecting a vast majority
of attacks. Addressing this limitation, we propose MKLDroid, a unified
framework that systematically integrates multiple views of apps for performing
comprehensive malware detection and malicious code localisation. The rationale
is that, while a malware app can disguise itself in some views, disguising in
every view while maintaining malicious intent will be much harder.
MKLDroid uses a graph kernel to capture structural and contextual information
from apps' dependency graphs and identify malice code patterns in each view.
Subsequently, it employs Multiple Kernel Learning (MKL) to find a weighted
combination of the views which yields the best detection accuracy. Besides
multi-view learning, MKLDroid's unique and salient trait is its ability to
locate fine-grained malice code portions in dependency graphs (e.g.,
methods/classes). Through our large-scale experiments on several datasets
(incl. wild apps), we demonstrate that MKLDroid outperforms three
state-of-the-art techniques consistently, in terms of accuracy while
maintaining comparable efficiency. In our malicious code localisation
experiments on a dataset of repackaged malware, MKLDroid was able to identify
all the malice classes with 94% average recall
Generalized Rank Pooling for Activity Recognition
Most popular deep models for action recognition split video sequences into
short sub-sequences consisting of a few frames; frame-based features are then
pooled for recognizing the activity. Usually, this pooling step discards the
temporal order of the frames, which could otherwise be used for better
recognition. Towards this end, we propose a novel pooling method, generalized
rank pooling (GRP), that takes as input, features from the intermediate layers
of a CNN that is trained on tiny sub-sequences, and produces as output the
parameters of a subspace which (i) provides a low-rank approximation to the
features and (ii) preserves their temporal order. We propose to use these
parameters as a compact representation for the video sequence, which is then
used in a classification setup. We formulate an objective for computing this
subspace as a Riemannian optimization problem on the Grassmann manifold, and
propose an efficient conjugate gradient scheme for solving it. Experiments on
several activity recognition datasets show that our scheme leads to
state-of-the-art performance.Comment: Accepted at IEEE International Conference on Computer Vision and
Pattern Recognition (CVPR), 201
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