Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Publicações

Publicações por CTM

2018

ML datasets as synthetic cognitive experience records

Autores
Castro, H; Andrade, MT;

Publicação
International Journal of Computer Information Systems and Industrial Management Applications

Abstract
Machine Learning (ML), presently the major research area within Artificial Intelligence, aims at developing tools that can learn, approximately on their own, from data. ML tools learn, through a training phase, to perform some association between some input data and some output evaluation of it. When the input data is audio or visual media (i.e. akin to sensory information) and the output corresponds to some interpretation of it, the process may be described as Synthetic Cognition (SC). Presently ML (or SC) research is heterogeneous, comprising a broad set of disconnected initiatives which develop no systematic efforts for cooperation or integration of their achievements, and no standards exist to facilitate that. The training datasets (base sensory data and targeted interpretation), which are very labour intensive to produce, are also built employing ad-hoc structures and (metadata) formats, have very narrow expressive objectives and thus enable no true interoperability or standardisation. Our work contributes to overcome this fragility by putting forward: a specification for a standard ML dataset repository, describing how it internally stores the different components of datasets, and how it interfaces with external services; and a tool for the comprehensive structuring of ML datasets, defining them as Synthetic Cognitive Experience (SCE) records, which interweave the base audio-visual sensory data with multilevel interpretative information. A standardised structure to express the different components of the datasets and their interrelations will promote re-usability, resulting on the availability of a very large pool of datasets for a myriad of application domains. Our work thus contributes to: the universal interpretability and reusability of ML datasets; greatly easing the acquisition and sharing of training and testing datasets within the ML research community; facilitating the comparison of results from different ML tools; accelerating the overall research process. © MIR Labs.

2018

Improving Audiovisual Content Annotation Through a Semi-automated Process Based on Deep Learning

Autores
Vilaça, L; Viana, P; Carvalho, P; Andrade, MT;

Publicação
Proceedings of the Tenth International Conference on Soft Computing and Pattern Recognition, SoCPaR 2018, Porto, Portugal, December 13-15, 2018

Abstract
Over the last years, Deep Learning has become one of the most popular research fields of Artificial Intelligence. Several approaches have been developed to address conventional challenges of AI. In computer vision, these methods provide the means to solve tasks like image classification, object identification and extraction of features. In this paper, some approaches to face detection and recognition are presented and analyzed, in order to identify the one with the best performance. The main objective is to automate the annotation of a large dataset and to avoid the costy and time-consuming process of content annotation. The approach follows the concept of incremental learning and a R-CNN model was implemented. Tests were conducted with the objective of detecting and recognizing one personality within image and video content. Results coming from this initial automatic process are then made available to an auxiliary tool that enables further validation of the annotations prior to uploading them to the archive. Tests show that, even with a small size dataset, the results obtained are satisfactory. © 2020, Springer Nature Switzerland AG.

2018

An FPGA array for cellular genetic algorithms: Application to the minimum energy broadcast problem

Autores
dos Santos, PV; Alves, JC; Ferreira, JC;

Publicação
MICROPROCESSORS AND MICROSYSTEMS

Abstract
The genetic algorithm is a general purpose optimization metaheuristic for solving complex optimization problems. Because the algorithm usually requires a large number of iterations to evolve a population of solutions to good final solutions, it normally exhibits long execution times, especially if running on low-performance conventional processors. In this work, we present a scalable computing array to parallelize and accelerate the execution of cellular GAs (cGAs). This is a variant of genetic algorithms which can conveniently exploit the coarse-grain parallelism afforded by custom parallel processing. The proposed architecture targets Xilinx FPGAs and was implemented as an auxiliary processor of an embedded soft-core CPU (MicroBlaze). To facilitate the customization for different optimization problems, a high-level synthesis design flow is proposed where the problem-dependent operations are specified in C++ and synthesised to custom hardware, thus demanding of the programmer only minimal knowledge of low-level digital design for FPGAs. To demonstrate the efficiency of the array processor architecture and the effectiveness of the design methodology, the development of a hardware solver for the minimum energy broadcast problem in wireless ad hoc networks is employed as a use case. Implementation results for a Virtex-6 FPGA show significant speedups, especially when comparing to embedded processors used in current FPGA devices.

2018

A Parallel-Pipelined OFDM Baseband Modulator with Dynamic Frequency Scaling for 5G Systems

Autores
Ferreira, ML; Ferreira, JC; Hübner, M;

Publicação
Applied Reconfigurable Computing. Architectures, Tools, and Applications - 14th International Symposium, ARC 2018, Santorini, Greece, May 2-4, 2018, Proceedings

Abstract
5G heterogeneity will cover a huge diversity of use cases, ranging from enhanced-broadband to low-throughput and low-power communications. To address such requirements variety, this paper proposes a parallel-pipelined architecture for an OFDM baseband modulator with clock frequency run-time adaptation through dynamic frequency scaling (DFS). It supports a set of OFDM numerologies recently proposed for 5G communication systems. The parallel-pipelined architecture can achieve high throughputs at low clock frequencies (up to 520.3 MSamples/s at 160 MHz) and DFS allows for the adjustment of baseband processing clock frequency according to immediate throughput demands. The application of DFS increases the system’s power efficiency by allowing power savings up to 62.5%; the resource and latency overhead is negligible. © Springer International Publishing AG, part of Springer Nature 2018.

2018

Flexible and Dynamically Reconfigurable FPGA-Based FS-FBMC Baseband Modulator

Autores
Ferreira, ML; Ferreira, JC;

Publicação
2018 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS)

Abstract
Filter-bank Multicarrier Modulation (FBMC) is a 5G waveform candidate with improved spectral efficiency and out-of-band emissions performance compared to OFDM. To address the challenge of designing flexible hardware infrastructures for future wireless communications, this paper presents a dynamically reconfigurable FPGA-based Frequency Spreading FBMC (FS-FBMC) baseband modulator. Based on a detailed modulator datapath analysis, the proposed architecture combines static multi-mode modules with dynamic partial reconfiguration (DPR) to achieve a flexible and evolvable system. Results show that our design is resource-efficient, due to hardware virtualization. Moreover, low-latency reconfiguration of static multimode modules combined with ICAP overclocking results in submillisecond reconfiguration times which are viable in the context of flexible communication systems, such as Cognitive Radios.

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.

  • 122
  • 324