60,699 research outputs found
Optimum buckling design of composite stiffened panels using ant colony algorithm
Optimal design of laminated composite stiffened panels of symmetric and balanced layup with different number of T-shape stiffeners is investigated and presented. The stiffened panels are simply supported and subjected to uniform biaxial compressive load. In the optimization for the maximum buckling load without weight penalty, the panel skin and the stiffened laminate stacking sequence, thickness and the height of the stiffeners are chosen as design variables. The optimization is carried out by applying an ant colony algorithm (ACA) with the ply contiguous constraint taken into account. The finite strip method is employed in the buckling analysis of the stiffened panels. The results shows that the buckling load increases dramatically with the number of stiffeners at first, and then has only a small improvement after the number of stiffeners reaches a certain value. An optimal layup of the skin and stiffener laminate has also been obtained by using the ACA. The methods presented in this paper should be applicable to the design of stiffened composite panels in similar loading conditions
Inferring Missing Entity Type Instances for Knowledge Base Completion: New Dataset and Methods
Most of previous work in knowledge base (KB) completion has focused on the
problem of relation extraction. In this work, we focus on the task of inferring
missing entity type instances in a KB, a fundamental task for KB competition
yet receives little attention. Due to the novelty of this task, we construct a
large-scale dataset and design an automatic evaluation methodology. Our
knowledge base completion method uses information within the existing KB and
external information from Wikipedia. We show that individual methods trained
with a global objective that considers unobserved cells from both the entity
and the type side gives consistently higher quality predictions compared to
baseline methods. We also perform manual evaluation on a small subset of the
data to verify the effectiveness of our knowledge base completion methods and
the correctness of our proposed automatic evaluation method.Comment: North American Chapter of the Association for Computational
Linguistics- Human Language Technologies, 201
Face recognition technologies for evidential evaluation of video traces
Human recognition from video traces is an important task in forensic investigations and evidence evaluations. Compared with other biometric traits, face is one of the most popularly used modalities for human recognition due to the fact that its collection is non-intrusive and requires less cooperation from the subjects. Moreover, face images taken at a long distance can still provide reasonable resolution, while most biometric modalities, such as iris and fingerprint, do not have this merit. In this chapter, we discuss automatic face recognition technologies for evidential evaluations of video traces. We first introduce the general concepts in both forensic and automatic face recognition , then analyse the difficulties in face recognition from videos . We summarise and categorise the approaches for handling different uncontrollable factors in difficult recognition conditions. Finally we discuss some challenges and trends in face recognition research in both forensics and biometrics . Given its merits tested in many deployed systems and great potential in other emerging applications, considerable research and development efforts are expected to be devoted in face recognition in the near future
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