SEL: A unified algorithm for salient entity linking

The entity linking task consists in automatically identifying and linking the entities mentioned in a text to their uniform resource identifiers in a given knowledge base. This task is very challenging due to its natural language ambiguity. However, not all the entities mentioned in the document have the same utility in understanding the topics being discussed. Thus, the related problem of identifying the most relevant entities present in the document, also known as salient entities (SE), is attracting increasing interest. In this paper, we propose salient entity linking, a novel supervised 2‐step algorithm comprehensively addressing both entity linking and saliency detection. The first step is aimed at identifying a set of candidate entities that are likely to be mentioned in the document. The second step, besides detecting linked entities, also scores them according to their saliency. Experiments conducted on 2 different data sets show that the proposed algorithm outperforms state‐of‐the‐art competitors and is able to detect SE with high accuracy. Furthermore, we used salient entity linking for extractive text summarization. We found that entity saliency can be incorporated into text summarizers to extract salient sentences from text. The resulting summarizers outperform well‐known summarization systems, proving the importance of using the SE information.     

Vision-based Control of a Delta Parallel Robot via Linear Camera-Space Manipulation

One of the open problems to control a parallel robot in real-time is the larger number of parameters to be incorporated in the control model when compared to serial robots. This paper presents an innovative vision-based method to control a delta-type parallel robot based on Linear Camera-Space Manipulation. The proposed method is a simple and robust technique capable of achieving real-time control of robots without relying on the calibration of either the robot or the environment parameters. To document the robustness of this technique, a sensitivity analysis was performed in simulation where the effect of two sources of error on the end-point positioning are considered. Such sources are the variability of each link’s parameters, and the uncertainty of the visual measurements. Experimental results on a Clavel’s delta parallel robot show that end-point positioning errors obtained with Linear Camera-Space Manipulation are less than 1.5 mm, demonstrating a low sensitivity to parameter uncertainty in qualitative agreement with the simulation results. The results show that the developed approach is advantageous to control parallel robots for industrial applications in real-time and can obviate to a number of open problems common with the control of parallel robots.     

Structural damage accumulation and control for life cycle optimum seismic performance of buildings

Seismic reliability and expected performance functions of structural systems are sensitive to the process of damage accumulation associated with the random sequences of ground motion excitations that those systems may experience. Optimum life cycle-based engineering decisions must examine the influence of concepts related to both the target safety level of the initial system and the eventual repair and maintenance actions that may be undertaken during the life of the system. This study includes an overview of the general framework supporting these decisions as well as some available results about (a) the influence of damage accumulation of the seismic vulnerability functions of building structures, (b) approximate estimates of accumulated damage and (c) optimum damage threshold values for repair of structural frames or replacement of energy dissipating devices. Some comments are presented concerning desirable studies about life cycle optimisation of systems exposed to different types of excitations.     

H∞ optimization with plant uncertainty and semidefinite programming

The fundamental H^∞ problem of control is that of finding the stable frequency response function that best fits worst case frequency domain specifications. This is a non-smooth optimization problem that underlies the frequency domain formulation of the H^∞ problem of control; it is the main optimization problem in qualitative feedback theory for example. It is shown in this article how the fundamental H^∞ optimization problem of control can be naturally treated with modern primal–dual interior point (PDIP) methods. The theory introduced here generalizes and unifies approaches to solving large classes of optimization problems involving matrix-valued functions, a subclass of which are commonly treated with linear matrix inequalities techniques. Also, in this article new optimality conditions for H^∞ optimization problems over matrix-valued functions are proved, and numerical experience on natural (PDIP) algorithms for these problems is reported. In experiments we find the algorithms exhibit (local) quadratic convergence rate in many instances. Finally, H^∞ optimization problems with an uncertainty parameter are considered. It is shown how to apply the theory developed here to obtain optimality conditions and derive algorithms. Numerical tests on simple examples are reported. © 1998 John Wiley & Sons, Ltd.     

Effect of the specimen dimensions and the test speed on the fracture toughness of iPP by the essential work of fracture (EWF) method

The fracture parameters of an isotactic polypropylene are studied by the essential work of fracture method. The influence of the specimen height, width and thickness and the effect of the test speed are investigated. Results show that this method is very useful for studying the plane‐stress fracture of this kind of materials in form of films and sheets. Varying the width (30 to 60 mm) and the test speed (2 to 100 mm/min) has no relevant influence, whereas the results are only length independent in a range from 40 to 100 mm. The influence of the thickness is very high, obtaining an important decrease of the specific essential work as the thickness is increased in a range from 38 to 2500 μm. This result is justified with the fracture surfaces obtained, observed by SEM, in which an evolution of the fracture behavior is seen as a function of thickness (38, 100, 500, 1000, 2500 μm). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 177–187, 1999     

Hamiltonian partial mixed finite element-state space symplectic semi-analytical approach for the piezoelectric smart composites and FGM analysis

A partial mixed finite element (FE)–state space method (SSM) semi-analytical approach is presented for the static analysis of piezoelectric smart laminate composite and functionally graded material (FGM) plates. Hence, using the Hamiltonian formalism, the three-dimensional piezoelectricity equations are first worked so that a partial mixed variational formulation, which retains the translational displacements, electric potential, transverse stresses, and transverse electric displacement as primary variables, is obtained; this allows, in particular, straightforward fulfillment of the electromechanical continuity constraints at the laminate interfaces. After an in-plane FE discretization only, the problem is first reduced, for a single layer, to a Hamiltonian eigenvalue problem that is solved using the symplectic approach; then, the multilayer solution is reached via the SSM propagator matrix. The proposed methodology is finally applied to the static analysis of piezoelectric-cross-ply hybrid laminated composite and FGM plates. In a comparison with open literature, available tabulated results show good agreements, thus validating the proposed approach.