3,251 research outputs found
Achieving Low-Complexity Maximum-Likelihood Detection for the 3D MIMO Code
The 3D MIMO code is a robust and efficient space-time block code (STBC) for
the distributed MIMO broadcasting but suffers from high maximum-likelihood (ML)
decoding complexity. In this paper, we first analyze some properties of the 3D
MIMO code to show that the 3D MIMO code is fast-decodable. It is proved that
the ML decoding performance can be achieved with a complexity of O(M^{4.5})
instead of O(M^8) in quasi static channel with M-ary square QAM modulations.
Consequently, we propose a simplified ML decoder exploiting the unique
properties of 3D MIMO code. Simulation results show that the proposed
simplified ML decoder can achieve much lower processing time latency compared
to the classical sphere decoder with Schnorr-Euchner enumeration
Ternary Syndrome Decoding with Large Weight
The Syndrome Decoding problem is at the core of many code-based
cryptosystems. In this paper, we study ternary Syndrome Decoding in large
weight. This problem has been introduced in the Wave signature scheme but has
never been thoroughly studied. We perform an algorithmic study of this problem
which results in an update of the Wave parameters. On a more fundamental level,
we show that ternary Syndrome Decoding with large weight is a really harder
problem than the binary Syndrome Decoding problem, which could have several
applications for the design of code-based cryptosystems
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Parallel data compression
Data compression schemes remove data redundancy in communicated and stored data and increase the effective capacities of communication and storage devices. Parallel algorithms and implementations for textual data compression are surveyed. Related concepts from parallel computation and information theory are briefly discussed. Static and dynamic methods for codeword construction and transmission on various models of parallel computation are described. Included are parallel methods which boost system speed by coding data concurrently, and approaches which employ multiple compression techniques to improve compression ratios. Theoretical and empirical comparisons are reported and areas for future research are suggested
A hierarchical evaluation methodology in speech recognition
In speech recognition vast hypothesis spaces are generated, so the search methods used and their speedup techniques are both of great importance. One way of getting a speedup gain is to search in multiple steps. In this multipass search technique the first steps use only a rough estimate, while the latter steps apply the results of the previous ones. To construct these raw tests we use simplified phoneme groups which are based on some distance function defined over phonemes. The tests we performed show that this technique could significantly speed up the recognition process
Image Captioning through Image Transformer
Automatic captioning of images is a task that combines the challenges of
image analysis and text generation. One important aspect in captioning is the
notion of attention: How to decide what to describe and in which order.
Inspired by the successes in text analysis and translation, previous work have
proposed the \textit{transformer} architecture for image captioning. However,
the structure between the \textit{semantic units} in images (usually the
detected regions from object detection model) and sentences (each single word)
is different. Limited work has been done to adapt the transformer's internal
architecture to images. In this work, we introduce the \textbf{\textit{image
transformer}}, which consists of a modified encoding transformer and an
implicit decoding transformer, motivated by the relative spatial relationship
between image regions. Our design widen the original transformer layer's inner
architecture to adapt to the structure of images. With only regions feature as
inputs, our model achieves new state-of-the-art performance on both MSCOCO
offline and online testing benchmarks
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