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Cross-view image matches have been widely explored on terrestrial image localization using aerial images from drones or satellites. This study expands the cross-view image match idea and proposes a cross-domain and cross-view localization framework. The method identifies the correlation between color aerial images and underwater acoustic images to improve the localization of underwater vehicles that travel in partially structured environments such as harbors and marinas. The approach is validated on a real dataset acquired by an underwater vehicle in a marina. The results show an improvement in the localization when compared to the dead reckoning of the vehicle., This work has been submitted to the IEEE Robotics and Automation Letters (RA-L) for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible more...

Forward-looking sonars (FLS) are perception sensors that are not affected by underwater turbidity. FLS are used in Remotely Operated Vehicles (ROVs) to help them in the tasks of exploration, navigation and region mapping. Besides the advantages of working with acoustic images rather than optical images, the former presents various challenges inherent to their construction. Classic Computer Vision (CV) algorithms do not achieve the same success with acoustic images. Furthermore, data-driven approaches are dictating the state-of-the-art in several tasks that require feature extraction. For example, Convolutional Neural Networks (CNNs) are already been used in several CV problems such as classification, image matching, image retrieval, place recognition and one-shot learning. CNNs are showing promising results for problems with FLS images as well. Unfortunately, there are as not as many public datasets and methods for FLS problems as we have for optical images. Knowing that CNNs are capable of mapping correctly millions of images into thousands of labels, we are proposing a novel framework of feature learning strategy for FLS images. In order to evaluate how well the methods generalize, we selected three different FLS annotated datasets for our experiments. Two of them are real-world FLS images from a harbour environment from different locations. The third is generated from a custom 3D scene integrated with open-source underwater robot simulators. In our experiments, we compared our method with state-of-theart approaches in an unknown environment achieving superior results. more...

Sonar images pose hindrances when being elucidated for applications such as underwater navigation and localization. On the other hand, satellite images are simpler to be interpreted, but require GPS that is unavailable underwater due to absorption phenomena. Thus, we propose a neural network capable of translating an acoustic image acquired underwater to a textured image. We called the process sonar-to-satellite translation. We adopted a state-of-the-art neural architecture on a dataset comprised of sonar data and their respective satellite images. The experimental results show our method can extract interesting features from acoustic images and generate an informative texture image. more...

Pervasive computing environments are nowadays more and more used as a supporting tool for cooperative workflows, e.g., in emergency management. A typical problem in these scenarios is the synthesis of workflows in presence of sets of services (hosted on mobile devices) with constrained behaviors, just before the collaborating team is dropped off in the operation field. In this paper, we propose a technique able to automatically synthesize distributed orchestrators, each one coordinating a service and synchronizing with the other orchestrators, given a target generic workflow to be carried out and a set of behaviorally-constrained services. more...

The tutorial aims at providing a deep comprehension of the Web service composition problem and automated techniques to tackle it. Web service composition is currently one the most hyped and addressed issue in the service oriented computing. Starting from an analysis of current technologies and standards for Web service composition, the tutorial will lead the attendees to consider formal models at the base of current proposals, and techniques that can be fruitfully considered to address automatic composition synthesis in each of them. More in detail, attendees will consider: (i) basic technologies and standards for Web service invocation and description (SOAP, UDDI, WSDL,...); (ii) advanced technologies and standards for orchestration and inter-organizational process enactment, in particular WS-BPEL and WS-CDL; (iii) models for Web service composition; (iv) formal tools for both data-centric and process-centric synthesis, including query reformulation a'la data integration, transition-systems based formalisms, trace-based formalisms, logics of programs and processes. In particular, we will show how these formal tools can be applied for automatic Web service composition; (v) current state-of-the-art research results in automatic service composition, drawing a comparison and defining a unifying framework more...

Current information systems are required to deal with more complex data with respect to traditional relational data. The database community has already proposed abstractions for these kinds of data, in particular in terms of semistructured data models. A semistructured model conceives a database essentially as a finite directed labeled graph whose nodes represent objects, and whose edges represent relationships between objects. In the same way as conjunctive queries form the core of any query language for the relational model, regular path queries (RPQs) and their variants are considered the basic querying mechanisms for semistructured data.Besides the basic task of query answering, i.e., evaluating a query over a database, databases should support other reasoning services related to querying. One of the most important is query containment, i.e., verifying whether for all databases the answer to a query is a subset of the answer to a second query. Another important reasoning service that has received considerable attention in the recent years is view-based query processing, which amounts to processing queries based on a set of materialized views, rather than on the raw data in the database.The goal of this paper is to describe basic results and techniques concerning query containment and view based query processing for the class of two-way regular-path queries (which extend RPQs with the inverse operator). We will demonstrate that the basic services for reasoning about two way regular path queries are decidable, thus showing that the limited form of recursion expressible by these queries does not endanger the decidability of reasoning. Besides the specific results, our methods show the power of two-way automata in reasoning on complex queries. more...

Source integration is one of the core problems in data warehousing. Two critical factors for the design and maintenance of applications requiring source integration, and in particular data warehouse applications, are conceptual modeling of the domain, and reasoning support over the conceptual representation. We present a novel approach to conceptual modeling for source integration, which allows for suitably modeling the global concepts of the application, the individual information sources, and the constraints among different sources. Our methodological framework relies on the reasoning services associated with the modeling formalism to support an incremental source integration phase within the data warehouse design process. more...

Class-based languages express knowledge in terms of objects and classes, and have inspired a huge number of formalisms in computer science. Description logics forma family of both class-based and logic-based knowledge representation languages which allow for modeling an application domain in terms of objects, classes and relationships between classes, and for reasoning about them. This paper presents an overview of the research carried out in the last years in description logics, with the main goal of illustrating how these logics provide the foundations for class-based knowledge representation formalisms. more...

Query answering using views amounts to computing the answer to a query having information only on the extension of a set of views. This problem is relevant in several fields, such as information integration, data warehousing, query optimization, mobile computing, and maintaining physical data independence. We address query answering using views in a context where queries and views are regular path queries, i.e., regular expressions that denote the pairs of objects in the database connected by a matching path. Regular path queries are the basic query mechanism when the database is conceived as a graph, such as in semistructured data and data on the Web. We study algorithms for answering regular path queries using views under different assumptions, namely, closed and open domain, and sound, complete, and exact information on view extensions. We characterize data, expression, and combined complexity of the problem, showing that the proposed algorithms are essentially optimal. Our results are the first to exhibit decidability in cases where the language for expressing the query and the views allows for recursion. more...

Information integration is one of the core problems in cooperative information systems. The authors argue that two critical factors for the design and maintenance of applications requiring information integration are conceptual modeling of the domain, and reasoning support over the conceptual representation. In particular they present a general architecture for information integration that explicitly includes a conceptual representation of the application. They illustrate how the architecture can express several integration settings and existing systems. They provide various arguments in favor of the conceptual level in the architecture and of automated reasoning over the conceptual representation. Finally, they present a specific proposal of an integration system which realizes the general architecture and is equipped with decidable reasoning procedures. more...

View-based query processing requires answering a query posed to a database only on the basis of the information on a set of views, which are again queries over the same database. This problem is relevant in many aspects of database management, and has been addressed by means of two basic approaches: query rewriting and query answering. In the former approach, one tries to compute a rewriting of the query in terms of the views, whereas in the latter, one aims at directly answering the query based on the view extensions. We study view based query processing for the case of regular-path queries, which are the basic querying mechanisms for the emergent field of semistructured data. Based on recent results, we first show that a rewriting is in general a co-NP function wrt to the size of view extensions. Hence, the problem arises of characterizing which instances of the problem admit a rewriting that is PTIME. A second contribution of the work is to establish a tight connection between view based query answering and constraint satisfaction problems, which allows us to show that the above characterization is going to be difficult. As a third contribution, we present two methods for computing PTIME rewritings of specific forms. The first method, which is based on the established connection with constraint satisfaction problems, gives us rewritings expressed in Datalog with a fixed number of variables. The second method, based on automata-theoretic techniques, gives us rewritings that are formulated as unions of conjunctive regular-path queries with a fixed number of variables. more...

International audience; In this position paper for the Dl'98 workshop, we present a discussion on the notion of structure and on the related reasoning problems. Structures are widely used in artificial intelligence to represent real-world concepts, especially in design, configuration and classification problems. A structure is a composite object --composite objects and structures are strongly related-- which has a number of parts that are interconnected and that can be composite objects themselves (structure = collection of parts + configuration information). more...