A Wireless EEG Acquisition Platform based on Embedded Systems

This paper proposes a wireless EEG acquisition platform based on Open Multimedia Architecture Platform (OMAP) embedded system. A high-impedance active dry electrode was tested for improving the scalp- electrode interface. It was used the sigma-delta ADS1298 analog-to-digital converter, and developed a “kernelspace” character driver to manage the communications between the converter unit and the OMAP’s ARM core. The acquired EEG signal data is processed by a “userspace” application, which accesses the driver’s memory, saves the data to a SD-card and transmits them through a wireless TCP/IP-socket to a PC. The electrodes were tested through the alpha wave replacement phenomenon. The experimental results presented the expected alpha rhythm (8-13 Hz) reactiveness to the eyes opening task. The driver spends about 725 μs to acquire and store the data samples. The application takes about 244 μs to get the data from the driver and 1.4 ms to save it in the SD-card. A WiFi throughput of 12.8Mbps was measured which results in a transmission time of 5 ms for 512 kb of data. The embedded system consumes about 200 mAh when wireless off and 400 mAh when it is on. The system exhibits a reliable performance to record EEG signals and transmit them wirelessly. Besides the microcontroller-based architectures, the proposed platform demonstrates that powerful ARM processors running embedded operating systems can be programmed with real-time constrains at the kernel level in order to control hardware, while maintaining their parallel processing abilities in high level software applications.

Utilização do método Multicritério AHP, na aquisição de um sistema ERP

The selection of an Enterprise Resource Planning (ERP) system is one of the most sensitive and highest impact processes in the area of information systems and technologies, because it supports and integrates the whole business of an organization. Hence the importance of deciding the best solution in order to contribute to the organization's competitiveness in a global and increasingly demanding market. Therefore, it is essential to provide tools to support decision making, turning complex and often intangible decisions into simple and quantifiable scenarios. This study addressed the adoption of the Analytical Hierarchy Process (AHP) multicriteria decision method to support the selection of an ERP system. The literature review was the source used to obtain the set of the most relevant criteria to be considered in this decision, which were subsequently validated through systematic application of various surveys of experts and people related to the field of ERP systems. To support the application of AHP, according to the model obtained in the study, it was developed a web application that will be available to the general public. The responsible for the acquisition of ERP systems can use it to easily apply the AHP method based on validated decision model. On the other hand, the web application can be used as a validation tool, allowing collecting data for future developments of the decision model.