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Publicações

2014

In vitro pilot study on bone heating during surgical implant bed preparation

Autores
Fangaia, S; Almeida, M; Carvalho, L; Nicolau, P;

Publicação
BIODENTAL ENGINEERING II

Abstract
Introduction: The atraumatic preparation of the implant bed and the presence of healthy bone factors have been considered essential for osseointegration of an implant. Heat generation during bone drilling has been related with the pressure applied by the operator, characteristics of the drill bit, the drilling depth, the type of irrigation, the rotational speed of the drilling time and the density of the bone tissue. Although bone drilling practice has been performed under irrigation, recent studies in the literature propose the use of a clinical protocol without irrigation. The primary objective of this study was to use an optical fibber Bragg grating sensor to measure thermal variations during implant bed preparation using surgical drills with a new surface coating. Materials and Methods: A literature review was performed and a pilot study designed using a fresh pig's jaw at room temperature, and three drilling groups were performed: Group I - Straumann (R) Drill without irrigation Group II - Straumann (R) Drill coated Titanium Nitride and Aluminum (NiTiAl) without irrigation. Group III (Control) - Straumann (R)) Drill with irrigation. The perforations were made sequentially, using drills of 2.2, 2.8 and 3.5 mm, to a depth of 10 mm, at a speed of 800 rpmand 0.2 mm/s under a constant force of 4N. Changes in temperature were recorded using an optical fibber Bragg grating sensor, placed in an intra-osseous location. Results: Implant bed preparation procedure produced a temperature rise of: 0.39 degrees C to 0.53 degrees C, 1.28 degrees C to 2.70 degrees C, and 1.57 degrees C to 4.39 degrees C in group I, II and III respectively. The drills coated with NiTiAl and without irrigation have a lower temperature increase when compared with the uncoated drills, maintaining the procedure without irrigation. Discussion and Conclusions: The optical fibber Bragg gratings sensors have the ability to register changes in temperature that occur during the preparation of the implant bed. The coating of surgical drills with NiTiAl caused a minor increase of temperature in comparison with drills without coating. Perforations without irrigation performed at a speed of 800 rpm with a force of 4N do not seem to significantly increase the temperature in bone.

2014

A peer-to-peer service architecture for the Smart Grid

Autores
Campos, F; Matos, M; Pereira, J; Rua, D;

Publicação
14-TH IEEE INTERNATIONAL CONFERENCE ON PEER-TO-PEER COMPUTING (P2P)

Abstract
Important challenges in interoperability, reliability, and scalability need to be addressed before the Smart Grid vision can be fulfilled. The sheer scale of the electric grid and the criticality of the communication among its subsystems for proper management, demands a scalable and reliable communication framework able to work in an heterogeneous and dynamic environment. Moreover, the need to provide full interoperability between diverse current and future energy and non-energy systems, along with seamless discovery and configuration of a large variety of networked devices, ranging from the resource constrained sensing devices to servers in data centers, requires an implementation-agnostic Service Oriented Architecture. In this position paper we propose that this challenge can be addressed with a generic framework that reconciles the reliability and scalability of Peer-to-Peer systems, with the industrial standard interoperability of Web Services. We illustrate the flexibility of the proposed framework by showing how it can be used in two specific scenarios.

2014

Trace-Based Reconfigurable Acceleration with Data Cache and External Memory Support

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

Publicação
2014 IEEE INTERNATIONAL SYMPOSIUM ON PARALLEL AND DISTRIBUTED PROCESSING WITH APPLICATIONS (ISPA)

Abstract
This paper presents a binary acceleration approach based on extending a General Purpose Processor (GPP) with a Reconfigurable Processing Unit (RPU), both sharing an external data memory. In this approach repeating sequences of GPP instructions are migrated to the RPU. The RPU resources are selected and organized off-line using execution trace information. The RPU core is composed of Functional Units (FUs) that correspond to single CPU instructions. The FUs are arranged in stages of mutually independent operations. The RPU can enable several stages in tandem, depending on the data dependencies. External data memory accesses are handled by a configurable dual-port cache. A prototype implementation of the architecture on a Spartan-6 FPGA was validated with 12 benchmarks and achieved an overall geometric mean speedup of 1.91x.

2014

An operating theater planning decision support system

Autores
Gomes, C; Sperandio, F; Peles, A; Borges, J; Brito, AC; Almada Lobo, B;

Publicação
Healthcare Administration: Concepts, Methodologies, Tools, and Applications

Abstract
The operating theater is the biggest hospital budget expenditure. The usage of surgery related resources and its intrinsic planning must be carefully devised in order to achieve better operational performance. However, from long to short term planning, the decision processes inherent to the operating theater are often the subject of empiricism. Moreover, the current hospital information systems available in Portuguese public hospitals lack a decision support system component, which could assist in achieving better planning solutions. This work reports the development of a centralized system for the operating theater planning to support decision-making tasks of surgeons, chief specialty managers, and hospital administration. Its main components concern surgery scheduling, operating theater's resource allocation and performance measurement. The enhancement of the planning processes, the increase of policy compliance, and the overall performance of the operating theater compared to the former methodologies are also discussed.

2014

AC drive systems based on six-phase machine with three neutrals

Autores
Sousa, RPR; Jacobina, CB; Melo, VFB; de Freitas, NB;

Publicação
2014 11th IEEE/IAS International Conference on Industry Applications

Abstract

2014

Energy-efficient wireless multimedia sensor networks using FM as a control channel

Autores
Sousa, F; Campos, R; Ricardo, M;

Publicação
ISCC

Abstract
IEEE 802.11-based wireless multimedia sensor networks (WMSN) are a cost-effective and flexible solution for video monitoring scenarios. Yet, they suffer from three major problems: bad performance, throughput unfairness, and energy inefficiency. Several approaches have been considered to tackle these problems but they are too restrictive or complex. In this paper we propose a scheduling approach using FM as a control channel to address the energy inefficiency problem. By taking advantage of the FM radio characteristics - higher coverage and lower energy consumption than Wi-Fi, our proposed approach uses FM as an always-on point-to-multipoint control channel used to turn off the nodes' Wi-Fi radio interfaces when they are not needed to transmit, receive, or relay data. Numerical and simulation analysis shows that our proposed scheduling mechanism significantly reduces energy consumption, while preserving performance and fairness characteristics.

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