549 research outputs found

    Optimization of a compiler from PDDL to Picat (Short Paper)

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    Picat is a new constraint logic programming language that has obtained promising results in international competitions. These re-sults have been achieved thanks to several features. The most effective of them is an efficient handling of a tabling technique applied to search al-gorithms. A compiler from PDDL to Picat, which automatically enables to run PDDL models in Picat, has been recently developed. This paper describes a method which automatically optimizes the output of such a compiler, using a different representation of the states that better takes advantage of Picat's Tabling technique

    Defeasible Reasoning in SROEL: from Rational Entailment to Rational Closure

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    In this work we study a rational extension SROELRTSROEL^R T of the low complexity description logic SROEL, which underlies the OWL EL ontology language. The extension involves a typicality operator T, whose semantics is based on Lehmann and Magidor's ranked models and allows for the definition of defeasible inclusions. We consider both rational entailment and minimal entailment. We show that deciding instance checking under minimal entailment is in general Π2P\Pi^P_2-hard, while, under rational entailment, instance checking can be computed in polynomial time. We develop a Datalog calculus for instance checking under rational entailment and exploit it, with stratified negation, for computing the rational closure of simple KBs in polynomial time.Comment: Accepted for publication on Fundamenta Informatica

    Parameterized verification of publish/subcribe protocols via Infinite-State Model Checking

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    We apply the Infinite-State Model Checking to formally specify and validate protocol skeletons for distributed systems with asynchronous communication and synchronous access to local data structures. More precisely, we validate the Redis Pub/Sub key-value Server. Redis is based on a publish-subscribe architecture used in Cloud Storage and Internet of Things ecosystems. For the considered protocol, we present a formal specification that combines ideas coming from round-based and shared-memory specification languages. The resulting model is validated via the SMT-based Infinite-state Model Checker Cubicle. In this setting we use unbounded arrays to model (1) arbitrary collections of publishers and subscribers, (2) unbounded shared memory used as a communication media between processes. Our model is validated using the symbolic backward reachability algorithm implemented in the tool. The peculiarity of the algorithm is that, upon termination, the resulting correctness proof is guaranteed to hold for every number of process instances

    Reconfigurable Antenna Systems: Platform implementation and low-power matters

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    Antennas are a necessary and often critical component of all wireless systems, of which they share the ever-increasing complexity and the challenges of present and emerging trends. 5G, massive low-orbit satellite architectures (e.g. OneWeb), industry 4.0, Internet of Things (IoT), satcom on-the-move, Advanced Driver Assistance Systems (ADAS) and Autonomous Vehicles, all call for highly flexible systems, and antenna reconfigurability is an enabling part of these advances. The terminal segment is particularly crucial in this sense, encompassing both very compact antennas or low-profile antennas, all with various adaptability/reconfigurability requirements. This thesis work has dealt with hardware implementation issues of Radio Frequency (RF) antenna reconfigurability, and in particular with low-power General Purpose Platforms (GPP); the work has encompassed Software Defined Radio (SDR) implementation, as well as embedded low-power platforms (in particular on STM32 Nucleo family of micro-controller). The hardware-software platform work has been complemented with design and fabrication of reconfigurable antennas in standard technology, and the resulting systems tested. The selected antenna technology was antenna array with continuously steerable beam, controlled by voltage-driven phase shifting circuits. Applications included notably Wireless Sensor Network (WSN) deployed in the Italian scientific mission in Antarctica, in a traffic-monitoring case study (EU H2020 project), and into an innovative Global Navigation Satellite Systems (GNSS) antenna concept (patent application submitted). The SDR implementation focused on a low-cost and low-power Software-defined radio open-source platform with IEEE 802.11 a/g/p wireless communication capability. In a second embodiment, the flexibility of the SDR paradigm has been traded off to avoid the power consumption associated to the relevant operating system. Application field of reconfigurable antenna is, however, not limited to a better management of the energy consumption. The analysis has also been extended to satellites positioning application. A novel beamforming method has presented demonstrating improvements in the quality of signals received from satellites. Regarding those who deal with positioning algorithms, this advancement help improving precision on the estimated position

    Embedding Intelligence. Designerly reflections on AI-infused products

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    Artificial intelligence is more-or-less covertly entering our lives and houses, embedded into products and services that are acquiring novel roles and agency on users. Products such as virtual assistants represent the first wave of materializa- tion of artificial intelligence in the domestic realm and beyond. They are new interlocutors in an emerging redefined relationship between humans and computers. They are agents, with miscommunicated or unclear proper- ties, performing actions to reach human-set goals. They embed capabilities that industrial products never had. They can learn users’ preferences and accordingly adapt their responses, but they are also powerful means to shape people’s behavior and build new practices and habits. Nevertheless, the way these products are used is not fully exploiting their potential, and frequently they entail poor user experiences, relegating their role to gadgets or toys. Furthermore, AI-infused products need vast amounts of personal data to work accurately, and the gathering and processing of this data are often obscure to end-users. As well, how, whether, and when it is preferable to implement AI in products and services is still an open debate. This condition raises critical ethical issues about their usage and may dramatically impact users’ trust and, ultimately, the quality of user experience. The design discipline and the Human-Computer Interaction (HCI) field are just beginning to explore the wicked relationship between Design and AI, looking for a definition of its borders, still blurred and ever-changing. The book approaches this issue from a human-centered standpoint, proposing designerly reflections on AI-infused products. It addresses one main guiding question: what are the design implications of embedding intelligence into everyday objects

    How to access ancient landscapes? Field survey and legacy data integration for research on Greek and Roman settlement patterns in Eastern Sicily

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    The integration of field survey data from Eastern Sicily (the Plain of Catania) with legacy data avai- lable for the region will expand our knowledge on Mediterranean ancient rural landscapes. With an extent of 430 km2, the area is a perfect case study due to its geographical unity and the number of archaeological projects (both excavations and surveys) carried out within it in recent decades. Indeed, combining data from earlier research projects with new archaeological survey data allows us to conduct a settlement pattern analysis of the project’s study area. Heterogenous datasets have been integrated throu- gh their implementation into a geo-database, featuring the management and integration of topographical units and archaeological entities through semantic relations. Through geospatial data analysis based on the complete gazetteer of archaeological sites (whether sherd scatters, ruins, caves dwellings, tombs or tracks), a new image of rural landscapes for this area of Eastern Sicily from the Greek Archaic to the Late Roman Age can be visualized, beyond the traditional Sicilia frumentaria narrative
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