A Knowledge-Based Service Composition Algorithm with Better QoS in Semantic Overlay

A semantic overlay network (SON) is a visual framework clustered under similar metaknowledge units such as ontologies, algorithms, and rule engines. Knowledge-based service composition (KC) has become a prominent aspect of building new and creative composed service through a combination of semantically similar information at the knowledge level. In this study, a promising approach to construct a standard knowledge model is developed to utilize the progress of KC. To evaluate and optimize the composition, we define the quantity of service (QoS) regarding user requirements in the KC instance, and a KC instance path with better QoS is found in the model using the KC algorithm. Simulation results prove that our approach has a tradeoff between efficiency and equality

A Trustworthy Approach to the Adaptive Composition of GeoServices

AbstractFor the automatic generation of geographical information service chain, this article defines the quality of service (QoS) metrics based on service response time, reliability, and matching degree, among others, and the error propagation model. Based on the semantic matching and trustworthiness assessment of the geographical information services, this article proposes a trustworthy adaptive composition framework and implementation algorithm for geographical information services, ensuring the composition of service chains to better meet various QoS constraints. The effectiveness of this approach is proven in the simulation experiments

Model pathway diagrams for the representation of mathematical models

Mathematical models are the foundation of numerical simulation of optoelectronic devices. We present a concept for a machine-actionable as well as human-understandable representation of the mathematical knowledge they contain and the domain-specific knowledge they are based on. We propose to use theory graphs to formalize mathematical models and model pathway diagrams to visualize them. We illustrate our approach by application to the van Roosbroeck system describing the carrier transport in semiconductors by drift and diffusion. We introduce an approach for the block-based composition of models from simpler components

UniTi: Unified composition and time for multi-domain model-based design

To apply model-based design to embedded systems that interface with the physical world, including simulation and verification, current tools fall short. They must provide mathematical (model) definitions that stay close to the specification of the system. They must allow multiple domains, such as the continuous-time, discrete-time and dataflow domain, in a single model including well-defined interaction. They must support model transformations for refining a model during development. And most importantly, they must accurately include and simulate different notions of time in the model. UniTi is a model-based design flow and modelling and simulation environment that delivers on all these aspects. It is based on components that are signal transformations, and therefore mathematical functions. However, in each domain the representation of a signal differs. As components have the same structure in each domain, we can use unified composition operators to represent multiple domains in a single model. Furthermore, this composition provides a unified perspective on time in the domains, even though we differentiate between different notions of time. Time becomes a local property of the model, allowing us to represent and simulate time transformations such as time delays exactly without losing efficiency. Finally, model transformations are defined for such components, which are used for refining and developing the model and which are guided by the design steps in the design flow. We will formally define the domains, composition operators and transformations of UniTi and verify the approach with a case study on a phased array beamforming system