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Publications

Publications by Pedro Diniz

2010

Compiling for Reconfigurable Computing: A Survey

Authors
Cardoso, JMP; Diniz, PC; Weinhardt, M;

Publication
ACM COMPUTING SURVEYS

Abstract
Reconfigurable computing platforms offer the promise of substantially accelerating computations through the concurrent nature of hardware structures and the ability of these architectures for hardware customization. Effectively programming such reconfigurable architectures, however, is an extremely cumbersome and error-prone process, as it requires programmers to assume the role of hardware designers while mastering hardware description languages, thus limiting the acceptance and dissemination of this promising technology. To address this problem, researchers have developed numerous approaches at both the programming languages as well as the compilation levels, to offer high-level programming abstractions that would allow programmers to easily map applications to reconfigurable architectures. This survey describes the major research efforts on compilation techniques for reconfigurable computing architectures. The survey focuses on efforts that map computations written in imperative programming languages to reconfigurable architectures and identifies the main compilation and synthesis techniques used in this mapping.

2008

IJE special issue on reconfigurable hardware systems

Authors
Cardoso, JMP; Diniz, PC;

Publication
INTERNATIONAL JOURNAL OF ELECTRONICS

Abstract
Three articles focusing on interesting architectural features and/or execution techniques which configurable architectures make more accessible are discussed. The Applied Reconfigurable Computing (ARC) workshop series has been devoted to addressing the role of software programmers and hardware designers in implementing configurable and reconfigurable architectures while still recognizing the value of configurable computing basic techniques and application areas. The first article, by Wu, Kanstein, Madsen and Berekovic, describes the application of multithreading to a coarse-grain reconfigurable architecture. The second article by Chikhi, Derrien, Noumsi and Quinton, is devoted to a specific architectural feature, the inclusion of FLASH memory to facilitate the implementation of image-based algorithms, an application that matches very well with FPGA configurable technology. Finally, a third article in this track by Hur, Wong and Vassiliadis, explores the use of point-to-point interconnects in a contemporary FPGA.

2010

Providing user context for mobile and social networking applications

Authors
Santos, AC; Cardoso, JMP; Ferreira, DR; Diniz, PC; Chainho, P;

Publication
PERVASIVE AND MOBILE COMPUTING

Abstract
The processing capabilities of mobile devices coupled with portable and wearable sensors provide the basis for new context-aware services and applications tailored to the user environment and daily activities. In this article, we describe the approach developed within the UPCASE project, which makes use of sensors available in the mobile device as well as sensors externally connected via Bluetooth to provide user contexts. We describe the system architecture from sensor data acquisition to feature extraction, context inference and the publication of context information in web-centered servers that support well-known social networking services. In the current prototype, context inference is based on decision trees to learn and to identify contexts dynamically at run-time, but the middleware allows the integration of different inference engines if necessary. Experimental results in a real-world setting suggest that the proposed solution is a promising approach to provide user context to local mobile applications as well as to network-level applications such as social networking services.

2010

Preprocessing techniques for context recognition from accelerometer data

Authors
Figo, D; Diniz, PC; Ferreira, DR; Cardoso, JMP;

Publication
PERSONAL AND UBIQUITOUS COMPUTING

Abstract
The ubiquity of communication devices such as smartphones has led to the emergence of context-aware services that are able to respond to specific user activities or contexts. These services allow communication providers to develop new, added-value services for a wide range of applications such as social networking, elderly care and near-emergency early warning systems. At the core of these services is the ability to detect specific physical settings or the context a user is in, using either internal or external sensors. For example, using built-in accelerometers, it is possible to determine whether a user is walking or running at a specific time of day. By correlating this knowledge with GPS data, it is possible to provide specific information services to users with similar daily routines. This article presents a survey of the techniques for extracting this activity information from raw accelerometer data. The techniques that can be implemented in mobile devices range from classical signal processing techniques such as FFT to contemporary string-based methods. We present experimental results to compare and evaluate the accuracy of the various techniques using real data sets collected from daily activities.

2011

Code Transformations for Embedded Reconfigurable Computing Architectures

Authors
Diniz, PC; Cardoso, JMP;

Publication
GENERATIVE AND TRANSFORMATIONAL TECHNIQUES IN SOFTWARE ENGINEERING III

Abstract
Embedded Systems permeate all aspects of our daily life, from the ubiquitous mobile devices (e.g., PDAs and smart-phones) to play-stations. set-top boxes, household appliances, and in every electronic system, be it large or small (e.g., in cars. wrist-watches). Most embedded systems are characterized by stringent design constraints such as reduced memory and computing capacity, severe power and energy restrictions, weight and space limitations, most importantly, very short life spans and thus strict design cycles. Reconfiguration has emerged as a key technology for embedded systems as it offers the promise of increased system performance and component number reduction. Reconfigurable components can be customized or specialized (even dynamically) to the task at hand, thereby executing specific tasks more efficiently leading to possible reductions of the weight and power. In this article, we introduce and discuss compilation techniques for reconfigurable embedded systems. We present specific compiler techniques focusing on source-level code transformations highlighting their potential and the applicability of generative programming techniques to this compilation domain.

2009

Mobile Context Provider for Social Networking

Authors
Santos, AC; Cardoso, JMP; Ferreira, DR; Diniz, PC;

Publication
ON THE MOVE TO MEANINGFUL INTERNET SYSTEMS: OTM 2009 WORKSHOPS

Abstract
The ability to infer user context based on a mobile device together with a set of external sensors opens up the way to new context-aware services and applications. In this paper, we describe a mobile context provider that makes use of sensors available in a smartphone as well as sensors externally connected via bluetooth. We describe the system architecture from sensor data acquisition to feature extraction, context inference and the publication of context information to well-known social networking services such as Twitter and Hi5. In the current prototype, context inference is based on decision trees, but the middleware allows the integration of other inference engines. Experimental results suggest that the proposed solution is a promising approach to provide user context to both local and network-level services.

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