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A widely adopted security mechanism is the specification of access control policies by means of the XACML language. In this paper, we propose a framework, called X-CREATE, for the systematic generation of test inputs (XACML requests). Differently from existing tools, XCREATE exploits the XACML Context Schema. In particular, the tool applies a XML-based methodology (XPT) to systematically produce a...
Radio Frequency IDentification (RFID) systems are becoming more and more popular in the field of ubiquitous computing, in particular for objects identification. An RFID system is composed by one or more readers and a number of tags. One of the main issues in an RFID network is the fast and reliable identification of all tags in the reader range. The reader issues some queries, and tags properly answer...
In ad-hoc networks, the video quality of real-time services is greatly decreased when bandwidth reduction and channel access delay occur. In this paper, a dynamic frame rate adjustment of video transmissions is proposed in case of network congestion. Simulation results show that our approach improves the quality of real-time video over IEEE 802.11 based vehicular networks by guaranteeing a better...
In every application domain, achieving interoperability among heterogenous information systems is a crucial challenge and alliances are formed to standardize data-exchange formats. In the healthcare sector, HL7-V3 provides the current international reference models for clinical and administrative documents. Codices, an Italian company, provides the PICASSO platform that uses HL7-V3 as the pivot format...
There is a growing interest for techniques and tools facilitating the testing of mobile systems. The movement of nodes is one of the relevant factors of context change in ubiquitous systems and a key challenge in the validation of context-aware applications. An approach is proposed to generate a testbed for service-oriented systems that takes into account a mobility model of the nodes of the network...
In temporal transcoding, motion vector composition algorithms are used to reduce the computation time of the transcoding process. In this paper, we propose a multi-level motion vector composition scheme for H.264 transcoding, with the bilinear interpolation (BI) function. Simulation results show that the proposed algorithm achieves a video quality comparable with that of the motion estimation process...
This paper addresses the problem of real-time video transmission in vehicular networks. We show that the video quality of real-time services is greatly decreased when there is network congestion in different traffic situations. We propose a solution that applies frame skipping and transcoding together with frame rate reduction techniques over IEEE 802.11 based vehicular networks. Our approach improves...
In this paper, we approach the problem of identifying a set of objects in an RFID network. We propose a modified version of slotted aloha protocol to reduce the number of transmission collisions. All tags select a slot to transmit their ID by generating a random number. If there is a collision in a slot, the reader broadcasts the next identification request only to tags which collided in that slot...
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