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Publicações

Publicações por João Canas Ferreira

2018

Design and Evaluation of a Low Power CGRA Accelerator for Biomedical Signal Processing

Autores
Avelar, HH; Ferreira, JC;

Publicação
21st Euromicro Conference on Digital System Design, DSD 2018, Prague, Czech Republic, August 29-31, 2018

Abstract
This work presents the design and analysis of a biological signal processing accelerator, including an interface controller and memory subsystem for a low-power CGRA. The controller design supports several operation modes, which can perform several applications when paired with the CGRA reconfiguration capabilities. Physical synthesis shows that the controller introduces only a 6 percent area and power overhead compared to the CGRA core, while allowing independent processing of inner loops at high frequencies and the exploitation of pipelining and parallelism. In-depth power analysis based on layout information was performed, including an evaluation of the use of power gating techniques. A practical case study (ECG signal processing) was also evaluated. © 2018 IEEE.

2017

Towards a type 0 hypervisor for dynamic reconfigurable systems

Autores
Janßen, B; Korkmaz, F; Derya, H; Hübner, M; Ferreira, ML; Ferreira, JC;

Publicação
International Conference on ReConFigurable Computing and FPGAs, ReConFig 2017, Cancun, Mexico, December 4-6, 2017

Abstract

2019

An FPGA-Oriented Baseband Modulator Architecture for 4G/5G Communication Scenarios

Autores
Ferreira, ML; Ferreira, JC;

Publicação
ELECTRONICS

Abstract
The next evolution in cellular communications will not only improve upon the performance of previous generations, but also represent an unparalleled expansion in the number of services and use cases. One of the foundations for this evolution is the design of highly flexible, versatile, and resource-/power-efficient hardware components. This paper proposes and evaluates an FPGA-oriented baseband processing architecture suitable for communication scenarios such as non-contiguous carrier aggregation, centralized Cloud Radio Access Network (C-RAN) processing, and 4G/5G waveform coexistence. Our system is upgradeable, resource-efficient, cost-effective, and provides support for three 5G waveform candidates. Exploring Dynamic Partial Reconfiguration (DPR), the proposed architecture expands the design space exploration beyond the available hardware resources on the Zynq xc7z020 through hardware virtualization. Additionally, Dynamic Frequency Scaling (DFS) allows for run-time adjustment of processing throughput and reduces power consumption up to 88%. The resource overhead for DPR and DFS is residual, and the reconfiguration latency is two orders of magnitude below the control plane latency requirements proposed for 5G communications.

2019

Dynamic Partial Reconfiguration of Customized Single-Row Accelerators

Autores
Paulino, NMC; Ferreira, JC; Cardoso, JMP;

Publicação
IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS

Abstract
The use of specialized accelerator circuits is a feasible solution to address performance and energy issues in embedded systems. This paper extends a previous field-programmable gate array-based approach that automatically generates pipelined customized loop accelerators (CLAs) from runtime instruction traces. Despite efficient acceleration, the approach suffered from high area and resource requirements when offloading a large number of kernels from the target application. This paper addresses this by enhancing the CLA with dynamic partial reconfiguration (DPR) support. Each kernel to accelerate is implemented as a variant of a reconfigurable area of the CLA which hosts all functional units and configuration memory. Evaluation of the proposed system is performed on a Virtex-7 device. We show, for a set of 21 kernels, that when comparing two CLAs capable of accelerating the same subset of kernels, the one which benefits from DPR can be up to 4.3x smaller. Resorting to DPR allows for the implementation of CLAs which support numerous kernels without a significant decrease in operating frequency and does not affect the initiation intervals at which kernels are scheduled. Finally, the area required by a CLA instance can be further reduced by increasing the IIs of the scheduled kernels.

2018

Analysis and evaluation of an energy-efficient routing protocol for WSNs combining source routing and minimum cost forwarding

Autores
Miyandoab, FD; Canas Ferreira, JC; Grade Tavares, VM;

Publicação
Journal of Mobile Multimedia

Abstract
Source routing (SR) minimum cost forwarding (MCF) – SRMCF – is a reactive, energy-efficient routing protocol proposed to improve the existent MCF methods utilized in heterogeneous wireless sensor networks (WSN). This paper presents an analytical analysis with experimental support that demonstrates the effectiveness of the proposed protocol. SRMCF stems from SR concepts and MCF methods exploited in ad hoc WSNs, where all unicast communications (between sensor nodes and the base station, or vice versa) use minimum cost paths. The protocol utilized in the present work was updated and now also handles link and node failures. Theoretical analysis and simulations show that the final protocol exhibits better throughput and energy consumption than MCF. Memory requirements for the routing table in the base station are also analyzed. Experimental results in a real scenario were obtained for implementations of both protocols, MCF and SRMCF, deployed in a small network of TelosB motes. Results show that SRMCF presents a 33% higher throughput and 24% less energy consumption than MCF. Extensive © 2019 River Publishers

2019

Wearable sensor networks for human gait

Autores
Da Silva, JM; Derogarian, F; Ferreira, JC; Tavares, VG;

Publicação
Wearable Technologies and Wireless Body Sensor Networks for Healthcare

Abstract
A new wearable data capture system for gait analysis is being developed. It consists of a pantyhose with embedded conductive yarns interconnecting customized sensing electronic devices that capture inertial and electromyographic signals and send aggregated information to a personal computer through a wireless link. The use of conductive yarns to build the myoelectric electrodes and the interconnections of the wired sensors network as well as the topology and functionality of the sensor modules are presented. © The Institution of Engineering and Technology 2017.

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