Convex Hulls in Image Processing : A Scoping Review

The demands of image processing related systems are robustness, high recognition rates, capability to handle incomplete digital information, and magnanimous flexibility in capturing shape of an object in an image. It is exactly here that, the role of convex hulls comes to play. The objective of this paper is twofold. First, we summarize the state of the art in computational convex hull development for researchers interested in using convex hull image processing to build their intuition, or generate nontrivial models. Secondly, we present several applications involving convex hulls in image processing related tasks. By this, we have striven to show researchers the rich and varied set of applications they can contribute to. This paper also makes a humble effort to enthuse prospective researchers in this area. We hope that the resulting awareness will result in new advances for specific image recognition applications.

Mellan frihet och kontroll : Om läroplanskonstruktioner i svensk skola

The aim of this thesis is to explore how different competing discourses in the historical context of the Swedish education development have qualified and disqualified different constructions of national curriculum. How and after what kind of principles is the curriculum constructed? What qualify who are going to be recognized as the author and addressee of the curriculum? These key ques-tions of the study are discussed in the first part of the thesis. My point of depar-ture is that the curriculum can be understood as a relation between freedom and control. In an educational system this relationship reflects the problematic ten-sion between the external demands from an authoritative center and the local need to independently reflect over educational issues. How these concepts are defined by the prevailing social discourses affect specific relations and construc-tions of curricula as a steering tool and a producer of specific teacher identities. In this sense, I claim that curriculum is constructed in different ways depending on which of the didactic questions are emphasized and answered and who is judged as the legitimate author. Based on this, three models of curriculum con-struction are formulated; the content based, the result based and the process based. These models are subsequently used as an analytical tool to examine the historical development of Swedish national curricula. The second part of the thesis investigates the Swedish education system and the production of the national curriculum as a product of rival discourses. The historical investigation begins 1842 when the first state curriculum was issued and the inquiry concludes in 2008. The findings indicate that no one single con-struction has been totally dominant and that there has been an on-going discur-sive struggle between different alternative and opinions about what teachers must do and be.

A dislocation based theory for the deformation hardening behavior of DP steels : Impact of martensite content and ferrite grain size

A dislocation model, accurately describing the uniaxial plastic stress-strain behavior of dual phase (DP) steels, is proposed and the impact of martensite content and ferrite grain size in four commercially produced DP steels is analyzed. It is assumed that the plastic deformation process is localized to the ferrite. This is taken into account by introducing a non-homogeneity parameter, f(e), that specifies the volume fraction of ferrite taking active part in the plastic deformation process. It is found that the larger the martensite content the smaller the initial volume fraction of active ferrite which yields a higher initial deformation hardening rate. This explains the high energy absorbing capacity of DP steels with high volume fractions of martensite. Further, the effect of ferrite grain size strengthening in DP steels is important. The flow stress grain size sensitivity for DP steels is observed to be 7 times larger than that for single phase ferrite.