Minkowski compactness measure

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Published in: Computational Intelligence (UKCI), 2013, 13th UK Workshop, Guildford UK. Date of Conference: 9-11 Sept. 2013Many compactness measures are available in the literature. In this paper we present a generalised compactness measure Cq(S) which unifies previously existing definitions of compactness. The new measure is based on Minkowski distances and incorporates a parameter q which modifies the behaviour of the compactness measure. Different shapes are considered to be most compact depending on the value of q: for q = 2, the most compact shape in 2D (3D) is a circle (a sphere); for q → ∞, the most compact shape is a square (a cube); and for q = 1, the most compact shape is a square (a octahedron). For a given shape S, measure Cq(S) can be understood as a function of q and as such it is possible to calculate a spectum of Cq(S) for a range of q. This produces a particular compactness signature for the shape S, which provides additional shape information. The experiments section of this paper provides illustrative examples where measure Cq(S) is applied to various shapes and describes how measure and its spectrum can be used for image processing applications

2D and 3D Shape Descriptors

The field of computer vision studies the computational tools and methods required for computers to be able to process visual information, for example images and video. Shape descriptors are one of the tools commonly used in image processing applications. Shape descriptors are mathematical functions which are applied to an image and produce numerical values which are representative of a particular characteristic of the image. These numerical values can then be processed in order to provide some information about the image. For example, these values can be fed to a classifier in order to assign a class label to the image. There are a number of shape descriptors already existing in the literature for 2D and 3D images. The aim of this thesis is to develop additional shape descriptors which provide an improvement over (or an alternative to) those already existing in the literature. A large majority of the existing 2D shape descriptors use surface information to produce a measure. However, in some applications surface information is not present and only partially extracted contours are available. In such cases, boundary based shape descriptors must be used. A new boundary based shape descriptor called Linearity is introduced. This measure can be applied to open or closed curve segments. In general the availability of 3D images is comparatively smaller than that of 2D images. As a consequence, the number of existing 3D shape descriptors is also relatively smaller. However, there is an increasing interest in the development of 3D descriptors. In this thesis we present two basic 3D measures which afterwards are modified to produce a range of new shape descriptors. All of these descriptors are similar in their behaviour, however they can be combined and applied in different image processing applications such as image retrieval and classification. This simple fact is demonstrated through several examples.Mexican Science Council (Consejo Nacional de Ciencia y Tecnologia, CONACyT

A Tunable Measure of 3D Compactness

The field of shape description can be applied in domains ranging from medicine to engineering. Defining new metrics may allow to better describe shapes. It is therefore an essential process of development of the field. In this work, a new family of compactness metrics is introduced. It is proven that they range over (0, 1] and are translation, rotation and scaling independent. The sphere is the shape that has the smallest volume for a fixed surface, this is a definition of compactness. Therefore, the metrics of this family are called compactness measures since they all reach 1 if and only if the considered shape is a sphere. The different metrics of the family are obtained by the modification of a parameter β involved in the mathematical definition of the metric. They are proven to be different from each other and a thorough study of their behaviour resulted in the formulation of two interesting conjectures concerning the limit cases of β. Finally several experiments investigate how McGill’s database classes of shapes are represented when using the new family

Technology Adoption by Groups: A Valence Perspective

While past research has contributed to an understanding of how organizations or individuals adopt technologies, little is known about how such adoption occurs in groups. Given the widespread acknowledgment that organizations are moving to group-based structures and that groups often utilize technologies for performing their tasks, it is critical that we understand how such collective social entities adopt technologies. Such an understanding can better guide investment and implementation decisions. In this paper, we draw on existing literature about groups, technology characteristics, and valence to conceptualize a model of technology adoption by groups (referred to as the TAG model). We view the TAG phenomenon as a process of communication and negotiation in which analytically distinct factors-such as the individual members\u27 a priori attitudes toward the technology, the majority subgroup\u27s opinion, high-status members\u27 opinions, substantive conflict, and relevant characteristics of the technology play an important role. We develop several theoretical propositions regarding the nature of the contribution of these factors toward an adoption decision and discuss measurement tradeoffs and guidelines

The theme of mediation in the writings of Simone Weil

A study of the theme of mediation necessarily involves a consideration of the two poles between which mediation takes place. This study therefore begins with an investigation of what Simone Weil saw to be man's exile in this world, and his desire for the Good which is God. Since God is unknown and unknowable, this desire cannot be focussed on any particular object, and the soul must experience a void in which there is no compensation for spiritual energy expended. This process is unnatural, however, and painful to man, and he is frequently tempted to focus his desire for the Good on some earthly object; society, by creating the illusion of being greater than the individual, often fulfils this role, and becomes the object of man's idolatry. If man refuses this idolatry and is willing to hold the contradiction posed by his dual nature he will find that all earthly creatures and objects can be mediators between himself and the God whom he desires. In this v/ay exile becomes a fulfilment, and the whole natural realm can speak to man of his supernatural home. All mediation-themes reach their culmination in Christ, whose suffering is seen as a perpetual cosmic process reconciling the universe with its creator. The study is therefore presented in three sections: dualism, idolatry (false mediation), and mediation proper. These are fully illustrated by reference to the whole sphere of Simone Weil's meditations, religious, political and philosophical. Appendices include previously unpublished material, together with relatively inaccessible articles and letters