Publications

Weidong (Tom) Cai

M. Jorge Cardoso

Georg Langs

Bjoern Menze

Dimitris N. Metaxas

Albert A. Montillo

William Wells

Shaoting Zhang

Albert C.S. Chung

M. Jenkinson

Annemie Ribbens

2016-01-01

Lecture Notes in Computer Science (publié)

Poisson Group Testing: A Probabilistic Model for Boolean Compressed Sensing

Amin Emad

Olgica Milenkovic

We introduce a novel probabilistic group testing framework, termed Poisson group testing, in which the number of defectives follows a right-… (voir plus)truncated Poisson distribution. The Poisson model has a number of new applications, including dynamic testing with diminishing relative rates of defectives. We consider both nonadaptive and semi-adaptive identification methods. For nonadaptive methods, we derive a lower bound on the number of tests required to identify the defectives with a probability of error that asymptotically converges to zero; in addition, we propose test matrix constructions for which the number of tests closely matches the lower bound. For semiadaptive methods, we describe a lower bound on the expected number of tests required to identify the defectives with zero error probability. In addition, we propose a stage-wise reconstruction algorithm for which the expected number of tests is only a constant factor away from the lower bound. The methods rely only on an estimate of the average number of defectives, rather than on the individual probabilities of subjects being defective.

2015-08-15

IEEE Transactions on Signal Processing (publié)

arxiv.org

Clinical Image-Based Procedures. Translational Research in Medical Imaging

Ian J. Gerard

Marta Kersten-Oertel

Simon Drouin

Jeffery Alan Hall

Kevin Petrecca

Dante De Nigris

D. Collins

2015-01-01

Lecture Notes in Computer Science (publié)

Poisson Group Testing: A Probabilistic Model for Boolean Compressed Sensing

Amin Emad

Olgica Milenkovic

We introduce a novel probabilistic group testing framework, termed Poisson group testing, in which the number of defectives follows a right-… (voir plus)truncated Poisson distribution. The Poisson model has a number of new applications, including dynamic testing with diminishing relative rates of defectives. We consider both nonadaptive and semi-adaptive identification methods. For nonadaptive methods, we derive a lower bound on the number of tests required to identify the defectives with a probability of error that asymptotically converges to zero; in addition, we propose test matrix constructions for which the number of tests closely matches the lower bound. For semiadaptive methods, we describe a lower bound on the expected number of tests required to identify the defectives with zero error probability. In addition, we propose a stage-wise reconstruction algorithm for which the expected number of tests is only a constant factor away from the lower bound. The methods rely only on an estimate of the average number of defectives, rather than on the individual probabilities of subjects being defective.

2014-10-20

ArXiv (prépublication)

arxiv.org

A Scalable Successive-Cancellation Decoder for Polar Codes

Alexandre J. Raymond

Polar codes are the first error-correcting codes to provably achieve channel capacity, asymptotically in code length, with an explicit const… (voir plus)ruction. However, under successive-cancellation decoding, polar codes require very long code lengths to compete with existing modern codes. Nonetheless, the successive cancellation algorithm enables very-low-complexity implementations in hardware, due to the regular structure exhibited by polar codes. In this paper, we present an improved architecture for successive-cancellation decoding of polar codes, making use of a novel semi-parallel, encoder-based partial-sum computation module. We also provide quantization results for realistic code length N=215, and explore various optimization techniques such as a chained processing element and a variable quantization scheme. This design is shown to scale to code lengths of up to N=221, enabled by its low logic use, low register use and simple datapaths, limited almost exclusively by the amount of available SRAM. It also supports an overlapped loading of frames, allowing full-throughput decoding with a single set of input buffers.

2014-10-15

IEEE Transactions on Signal Processing (publié)

arxiv.org

High-Throughput Energy-Efficient LDPC Decoders Using Differential Binary Message Passing

Kevin Cushon

Saied Hemati

Camille Leroux

Shie Mannor

In this paper, we present energy-efficient architectures for decoders of low-density parity check (LDPC) codes using the differential decodi… (voir plus)ng with binary message passing (DD-BMP) algorithm and its modified variant (MDD-BMP). We also propose an improved differential binary (IDB) decoding algorithm. These algorithms offer significant intrinsic advantages in the energy domain: simple computations, low interconnect complexity, and very high throughput, while achieving error correction performance up to within 0.25 dB of the offset min-sum algorithm. We report on fully parallel decoder implementations of (273, 191), (1023, 781), and (4095, 3367) finite geometry-based LDPC codes in 65 nm CMOS. Using the MDD-BMP algorithm, these decoders achieve respective areas of 0.28 mm2, 1.38 mm2, and 15.37 mm2, average throughputs of 37 Gbps, 75 Gbps, and 141 Gbps, and energy efficiencies of 4.9 pJ/bit, 13.2 pJ/bit, and 37.9 pJ/bit with a 1.0 V supply voltage in post-layout simulations. At a reduced supply voltage of 0.8 V, these decoders achieve respective throughputs of 26 Gbps, 54 Gbps, and 94 Gbps, and energy efficiencies of 3.1 pJ/bit, 8.2 pJ/bit, and 23.5 pJ/bit. We also report on a fully parallel implementation of IDB for the (2048, 1723) LDPC code specified in the IEEE 802.3an (10GBASE-T) standard. This decoder achieves an area of 1.44 mm2, average throughput of 172 Gbps, and an energy efficiency of 2.8 pJ/bit with a 1.0 V supply voltage; at 0.8 V, it achieves throughput of 116 Gbps and energy efficiency of 1.7 pJ/bit.

2014-02-01

IEEE Transactions on Signal Processing (publié)

High-Throughput Energy-Efficient LDPC Decoders Using Differential Binary Message Passing

Kevin Cushon

Saied Hemati

Camille Leroux

Shie Mannor

In this paper, we present energy-efficient architectures for decoders of low-density parity check (LDPC) codes using the differential decodi… (voir plus)ng with binary message passing (DD-BMP) algorithm and its modified variant (MDD-BMP). We also propose an improved differential binary (IDB) decoding algorithm. These algorithms offer significant intrinsic advantages in the energy domain: simple computations, low interconnect complexity, and very high throughput, while achieving error correction performance up to within 0.25 dB of the offset min-sum algorithm. We report on fully parallel decoder implementations of (273, 191), (1023, 781), and (4095, 3367) finite geometry-based LDPC codes in 65 nm CMOS. Using the MDD-BMP algorithm, these decoders achieve respective areas of 0.28 mm2, 1.38 mm2, and 15.37 mm2, average throughputs of 37 Gbps, 75 Gbps, and 141 Gbps, and energy efficiencies of 4.9 pJ/bit, 13.2 pJ/bit, and 37.9 pJ/bit with a 1.0 V supply voltage in post-layout simulations. At a reduced supply voltage of 0.8 V, these decoders achieve respective throughputs of 26 Gbps, 54 Gbps, and 94 Gbps, and energy efficiencies of 3.1 pJ/bit, 8.2 pJ/bit, and 23.5 pJ/bit. We also report on a fully parallel implementation of IDB for the (2048, 1723) LDPC code specified in the IEEE 802.3an (10GBASE-T) standard. This decoder achieves an area of 1.44 mm2, average throughput of 172 Gbps, and an energy efficiency of 2.8 pJ/bit with a 1.0 V supply voltage; at 0.8 V, it achieves throughput of 116 Gbps and energy efficiency of 1.7 pJ/bit.

2014-02-01

IEEE Transactions on Signal Processing (publié)

Bayesian and grAphical Models for Biomedical Imaging

M. Cardoso

Ivor J. A. Simpson

Doina Precup

Annemie Ribbens

2014-01-01

Lecture Notes in Computer Science (publié)

Bayesian and grAphical Models for Biomedical Imaging

M. Jorge Cardoso

Ivor J. A. Simpson

Doina Precup

Annemie Ribbens

2014-01-01

Lecture Notes in Computer Science (publié)

Machine Learning and Interpretation in Neuroimaging

Irina Rish

Georg Langs

Leila Wehbe

Guillermo Cecchi

Kai-min Kevin Chang

Brian G Murphy

2014-01-01

Lecture Notes in Computer Science (publié)

Experimental Algorithms

Samuel Rosat

Issmail ElHallaoui

François Soumis

Andrea Lodi

2013-11-01

Lecture Notes in Computer Science (publié)

Adaptive Multiset Stochastic Decoding of Non-Binary LDPC Codes

Alexandru Ciobanu

Saied Hemati

We propose a non-binary stochastic decoding algorithm for low-density parity-check (LDPC) codes over GF(q) with degree two variable nodes, c… (voir plus)alled Adaptive Multiset Stochastic Algorithm (AMSA). The algorithm uses multisets, an extension of sets that allows multiple occurrences of an element, to represent probability mass functions that simplifies the structure of the variable nodes. The run-time complexity of one decoding cycle using AMSA is O(q) for conventional memory architectures, and O(1) if a custom memory architecture is used. Two fully-parallel AMSA decoders are implemented on FPGA for two (192,96) (2,4)-regular codes over GF(64) and GF(256), both achieving a maximum clock frequency of 108 MHz. The GF(64) decoder has a coded throughput of 65 Mb/s at Eb/N0=2.4 dB when using conventional memory, while a decoder using the custom memory version can achieve 698 Mb/s at the same Eb/N0. At a frame error rate (FER) of 2×10-6 the GF(64) version of the algorithm is only 0.04 dB away from the floating-point SPA performance, and for the GF(256) code the difference is 0.2 dB. To the best of our knowledge, this is the first fully parallel non-binary LDPC decoder over GF(256) reported in the literature.

2013-08-15

IEEE Transactions on Signal Processing (publié)