José Carlos Ribeiro

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The new IEEE 802.21 standard specifies link layer intelligence and other related network information to upper layers in order to optimize handovers between networks of different types, such as WiMAX, Wi-Fi, and 3GPP. This paper makes a short description of 802.21 standard, how it is implemented in ns-2, and the signaling used in a handover between WiMAX and(More)
Female patient, 42-years-old, complaining of difficulty in urinating and swelling in the vulvar area for one year. Her gynecological examination showed extensive injury in the vulvar region and the biopsy done was inconclusive. The removal of the lesion was conducted. After the procedure, the patient remains free of recurrence for 15 months. This case(More)
— This paper presents a characterization of spectrum opportunities in GSM900 downlink bands, for fixed and mobile scenarios. A testbed to analyze coexistence between the licensed GSM900 downlink system and an OFDM based secondary system that opportunistically shares the same spectrum is presented. Coexistence analysis is based on metrics such as spectrum(More)
This paper concerns the "H" reflex in eleven patients with spastic spinal cord injury (C5-T10), treated with Baclofen (50 mg/day) or Diazepam (20 mg/day). The "H" reflex was tested in the tibial nerve before and 15 days after the interrupted use of the drugs. Five patients used Baclofen and 6 patients used Diazepam. The latency time was measured. All the(More)
This paper proposes some reflections concerning the process of creation of multiple virtual identities usually verified in several online social platforms of informal interaction based on textual/synchronous modality. With this intention, it discusses characterization, exploratory possibilities (personal and social-communicative) and reasons which lead(More)
— This paper describes a new security framework that will leverage the security in cognitive radio cooperative protocols. The architecture uses the 802.1X access control mechanism and is supported by a Key Distribution Center (KDC) built upon an 802.1X Authentication Server. The KDC is used, together with a new terminal identification policy and modified(More)