New generations of distributed systems are opening novel perspectives for logic programming (LP): on the one hand, service-oriented architectures represent nowadays the standard approach for distributed systems engineering; on the other hand, pervasive systems mandate for situated intelligence. In this paper we introduce the notion of Logic Programming as a Service (LPaaS) as a means to address the needs of pervasive intelligent systems through logic engines exploited as a distributed service. First we define the abstract architectural model by re-interpreting classical LP notions in the new context; then we elaborate on the nature of LP interpreted as a service by describing the basic LPaaS interface. Finally, we show how LPaaS works in practice by discussing its implementation in terms of distributed tuProlog engines, accounting for basic issues such as interoperability and configurability.
The SOA paradigm is widely used in scenarios @cite_24 @cite_48 @cite_47 @cite_52 @cite_16 @cite_50 . Moreover, communication via REST enables the direct integration of SOA-ready devices (i.e. devices hosting native web services).
@cite_48 @cite_52 @cite_24 @cite_50 @cite_47 @cite_16
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We investigate a relay network where the source can potentially utilize an untrusted non-regenerative relay to augment its direct transmission of a confidential message to the destination. Since the relay is untrusted, it is desirable to protect the confidential data from it while simultaneously making use of it to increase the reliability of the transmission. We first examine the secrecy outage probability (SOP) of the network assuming a single antenna relay, and calculate the exact SOP for three different schemes: direct transmission without using the relay, conventional non-regenerative relaying, and cooperative jamming by the destination. Subsequently, we conduct an asymptotic analysis of the SOPs to determine the optimal policies in different operating regimes. We then generalize to the multi-antenna relay case and investigate the impact of the number of relay antennas on the secrecy performance. Finally, we study a scenario where the relay has only a single RF chain which necessitates an antenna selection scheme, and we show that unlike the case where all antennas are used, under certain conditions the cooperative jamming scheme with antenna selection provides a diversity advantage for the receiver. Numerical results are presented to verify the theoretical predictions of the preferred transmission policies. Service-oriented architecture (SOA) is a relatively new approach to software system development. It divides system functionality to independent, loosely coupled, interoperable services. In this paper we propose a new heterogeneous specification approach for SOA systems where a heterogeneous structured specification consists of a number of specifications of individual services written in a "local" logic and where the specification of their interactions is separately described in a "global" logic. A main feature of our global logic is the possibility of describing the dynamic change of service communications over time. Our approach is based on the theory of institutions: we show that both logics form institutions and that these institutions are connected by an institution comorphism. We illustrate our approach by a simple scenario of an e-university management system and show the power of the heterogeneous specification approach by a compositional refinement of the scenario. The increasing usage of smart embedded devices in business blurs the line between the virtual and real worlds. This creates new opportunities to build applications that better integrate real-time state of the physical world, and hence, provides enterprise services that are highly dynamic, more diverse, and efficient. Service-Oriented Architecture (SOA) approaches traditionally used to couple functionality of heavyweight corporate IT systems, are becoming applicable to embedded real-world devices, i.e., objects of the physical world that feature embedded processing and communication. In such infrastructures, composed of large numbers of networked, resource-limited devices, the discovery of services and on-demand provisioning of missing functionality is a significant challenge. We propose a process and a suitable system architecture that enables developers and business process designers to dynamically query, select, and use running instances of real-world services (i.e., services running on physical devices) or even deploy new ones on-demand, all in the context of composite, real-world business applications. With the Internet of Things, more and more devices become remotely manageable. The amount and heterogeneity of managed devices make the task of implementing management functionality challenging. Future Pervasive Computing scenarios require implementing a plethora of services to provide management functionality. With growing demand on services, reducing the emerging complexity becomes increasingly important. A simple-to-use programming model for implementing complex management scenarios is essential to enable developers to create the growing amount of required management software at high quality. The paper presents how data-centric mechanisms, as known from network management, can be utilized to create a service-oriented architecture (SOA) for management services. The resulting shift of complexity from access functionality towards data structures introduces new flexibility and facilitates the programming of management applications significantly. This is evaluated with a user study on the reference implementation.