Solving a real-time allocation problem with constraint programming

In this paper, we present an original approach (CPRTA for “Constraint Programming for solving Real-Time Allocation”) based on constraint programming to solve a static allocation problem of hard real-time tasks. This problem consists in assigning periodic tasks to distributed processors in the context of fixed priority preemptive scheduling. CPRTA is built on dynamic constraint programming together with a learning method to find a feasible processor allocation under constraints. Two efficient new approaches are proposed and validated with experimental results. Moreover, CPRTA exhibits very interesting properties. It is complete (if a problem has no solution, the algorithm is able to prove it); it is non-parametric (it does not require specific tuning) thus allowing a large diversity of models to be easily considered. Finally, thanks to its capacity to explain failures, it offers attractive perspectives for guiding the architectural design process.     

Region-Based Hierarchical Image Matching

This paper presents an approach to region-based hierarchical image matching, where, given two images, the goal is to identify the largest part in image 1 and its match in image 2 having the maximum similarity measure defined in terms of geometric and photometric properties of regions (e.g., area, boundary shape, and color), as well as region topology (e.g., recursive embedding of regions). To this end, each image is represented by a tree of recursively embedded regions, obtained by a multiscale segmentation algorithm. This allows us to pose image matching as the tree matching problem. To overcome imaging noise, one-to-one, many-to-one, and many-to-many node correspondences are allowed. The trees are first augmented with new nodes generated by merging adjacent sibling nodes, which produces directed acyclic graphs (DAGs). Then, transitive closures of the DAGs are constructed, and the tree matching problem reformulated as finding a bijection between the two transitive closures on DAGs, while preserving the connectivity and ancestor-descendant relationships of the original trees. The proposed approach is validated on real images showing similar objects, captured under different types of noise, including differences in lighting conditions, scales, or viewpoints, amidst limited occlusion and clutter.     

Mirror uncertainty and uniqueness conditions for determining shape and motion from orthographic projection

This paper presents new forms of necessary and sufficient conditions for determining shape and motion to within a mirror uncertainty from monocular orthographic projections of any number of point trajectories over any number of views. The new forms of conditions use image data only and can therefore be employed in any practical algorithms for shape and motion estimation. We prove that the mirror uncertainty for the three view problem also exists for a long sequence: if shapeS is a solution, so is its mirror imageS which is symmetric toS about the image plane. The necessary and sufficient conditions for determining the two sets of solutions are associated with the rank of the measurement matrixW.If the rank ofW is 3, then the original 3D scene points cannot be coplanar and the shape and motion can be determined to within a mirror uncertainty from the image data if and only if there are three distinct views. This condition is different from Ullman's theorem (which states thatthree distinct views of four noncoplanar points suffice to determine the shape and motion up to a reflection) in two aspects: (1) it is expressed in terms of image data; (2) it applies to a long image sequence in a homogeneous way.If the rank ofW is 2 and the image points in at least one view are not colinear in the image plane, then there are two possibilities: either the motion is around the optical axis, or the 3-D points all lie on the same plane. In the first case, the motion can be determined uniquely but the shape is not determined. In the second case, a necessary and sufficient condition is to be satisfied and at least 3 point trajectories over at least 3 distinct views are needed to determine the shape in each view to within a mirror uncertainty, and the number of motion solutions is equal to the combinatorial number of the possible positions of the plane in different views. The necessary and sufficient condition is associated with the rank of a matrixC: ifC has a rank of 1, the plane is undetermined; ifC has a rank of 2 (implying there are exactly 3 distinct views), then a necessary and sufficient condition, whose physical meaning is not completely clear, is to be satisfied to determine the plane to within 2 sets; ifC has a rank of 3 (implying there are 4 or more distinct views), then the plane can always be determined to within two sets.If the rank ofW is 2 or 1 and the image points in each view are colinear in the image plane, then the three dimensional motion problem reduces to a two dimensional motion problem. In this case, the uniqueness condition is associated with the rank of the reduced measurement matrix . If has a rank of 2, then the original 3D points cannot be colinear in the space and the shape and motion can be determined to within two sets if and only if three or more views are distinct. If has a rank of 1, there are two possibilities: if the rows of are identical, then either the original 3D points are not colinear and the motion is zero, or the points are colinear and possibly move between two mirror symmetric positions; if the rows of are not identical, then the motion is not determined.All proofs are constructive and thus define an algorithm for determining the uniqueness of solution as well as for estimating shape and motion from point trajectories.     

Characterization and evaluating the mechanical performance of halloysite nanotubes reinforced acrylonitrile butadiene styrene/polycarbonate composites exposed to aggressive environmental conditions

Developing light weight polymer based composites dispersed with novel reinforcements which can function well in the presence of aggressive environments is an active research field in the materials engineering. Hence, in the current work, halloysite nanotubes (1 %, 2 %, 4 %, 6 %, 8 % and 10 % by weight) were reinforced into acrylonitrile butadiene styrene/polycarbonate blend and the role of reinforcing phases on the mechanical performance under aggressive environmental conditions has been evaluated. Hardness was measured as gradually increased in the composites with the increased content of the reinforcements. Impact strength of the composites was observed as increased in the composites up to 4 % reinforcement and further decreased. Increased strength was measured for the composite up to 2 % reinforcement. Ductility of the composites was decreased as reflected form the decreased % of elongation with the higher fraction of reinforcements due to induced brittleness. The composites were exposed to diluted sulfuric acid for 3 h and 6 h at 60 °C and then subjected to tensile loading. With the increased time of exposure, composites with 1 % and 2 % reinforcement exhibited relatively better performance.     

Ontologies for Specifying and Reconciling Contexts of Web Services

This paper presents an ontology-based approach for the specification (using as a definition language) and reconciliation (using as a mediation tool) of contexts of Web services. Web services are independent components that can be triggered and composed for the satisfaction of user needs (e.g., hotel booking). Because Web services originate from different providers, their composition faces the obstacle of the context heterogeneity featuring these Web services. An unawareness of this context heterogeneity during Web services composition and execution results in a lack of the quality and relevancy of information that permits tracking the composition, monitoring the execution, and handling exceptions.     

Notes on ensembles of IoT,network functions and clouds for service-oriented computing and applications

Many advances have been introduced recently for service-oriented computing and applications (SOCA). The Internet of Things (IoT) has been pervasive in various application domains. Fog/Edge computing models have shown techniques that move computational and analytics capabilities from centralized data centers where most enterprise business services have been located to the edge where most customer’s Things and their data and actions reside. Network functions between the edge and the cloud can be dynamically provisioned and managed through service APIs. Microservice architectures are increasingly used to simplify engineering, deployment and management of distributed services in not only cloud-based powerful machines but also in light-weighted devices. Therefore, a key question for the research in SOCA is how do we leverage existing techniques and develop new ones for coping with and supporting the changes of data and computation resources as well as customer interactions arising in the era of IoT and Fog/Edge computing. In this editorial paper, we attempt to address this question by focusing on the concept of ensembles for IoT, network functions and clouds.