An orthogonal series density estimation approach to reconstructing positron emission tomography images

Positron emission tomography (PET) is an important medical imaging technique. Statistically, the PET image reconstruction problem comprises estimating the intensity function of a non-homogeneous Poisson process from a set of indirectly observed data (an integral transform is involved). In this paper, we investigate a new reconstruction method consisting in the adaptation of orthogonal series density estimation techniques to use with an idealised form of the PET problem. The method provides reasonable reconstructions quickly; its computational speed is its major advantage. It has further advantages (e.g. no pixellation required) and various disadvantages (e.g. difficulties with object boundaries, non-negativity not guaranteed) which are discussed. Its major disadvantage, however, is the difficulty associated with generalising the approach to cope with more realistic versions of the PET model.     

The Learning Organization: Adult Learning and Organizational Transformation

The concept of the ‘learning organization’, with its roots in self-development and action-learning, has recently caught the imagination of many organizations and researchers. However, emerging definitions are creating ambiguity. There is, therefore, a need to add substance to them, and widen our understanding of what the concept means, by concentrating on what is meant by ‘learning’, and focusing on exactly how adults learn. Understanding and facilitating adult learning in organizations is, by and large, a confused activity that fails to connect with an individual's other experiences and needs, and with what modern psychology and research have to teach us. In particular, learning and skills need to be linked to the questioning of purpose and value in an organization.     

Which Label? An Investigation into the Effects of Terminology on Public Perceptions of and Attitudes towards People with Learning Difficulties

There is much rhetoric around the damaging effect of certain labels applied to people with learning difficulties. This empirical study investigated the effect of three different labels in current usage on public perceptions of the groups so labelled. The labels contrasted were 'mentally subnormal', 'mentally handicapped' and 'people with learning difficulties'. Three independent groups of subjects were presented with an attitude questionnaire. This included a semantic differential scale to ascertain a stereotype of the labelled group, a social distance scale, and a series of questions to tap attitudes regarding people's abilities and rights. Each group was questioned with reference to one of the three labels only. A total of 111 subjects took part. The main findings supported the view that the term 'learning difficulties' is associated with more positive attitudes than either of the other labels which do not significantly differ from each other. However there was also evidence that people labelled as having 'learning difficulties' were thought to be less deserving of special provision. The implications of these findings are discussed in relation to present and future uses of labels.     

Strategic management step by step

This paper summarizes the application of Strategic Decision Making Process in a small company. The project described is an example taken from in-company projects conducted by the CAPITB Management Advisory Unit across the industry sectors and was part of the Strategic Decision Making Process Research and Project Work Programme.It describes the stages and work involved in the development and implementation of the Company's strategy and also identifies some of the benefits and problems which stemmed from the work.     

A MOMENT IDENTITY

A moment identity based on the concept of weighted distributions is presented. The identity has potential applications to problems involving the manipulation of expectations of functions of random variables. Several examples, mainly concerning the evaluation of the risk of shrinkage estimators of several parameters, are given.     

Time-use auditing: An approach to validating social indicators

Following McCal,, ‘quality of life’ is defined as objective social conditions necessary to the general happiness, where ‘happiness’ is understood in the broad sense, as including all forms of intrinsically valuable experience, not just ‘feeling happy’. The argument is then made that in order for this definition to be fully implemented happiness in the broad sense must also be assessed. The latter half of the paper is devoted to describing a set of procedures, collectively called ‘time-use auditing’, for determining the extent to which an individual person is happy, in the broad sense, in a stated interval of time. Intrinsically valuable experience is analyzed into two dimensions: duration and level. The first is determined by time-budgeting and the second (in a general way) by Maslow's hierarchy of needs. Specifically, Maslow's hierarchy is spelled out in concrete terms by means of “time-use rating structures’, each one specific to a particular time-use category; the authors have written rating structures for adolescents of either sex, ages 12 to 17 inclusive. By way of illustration, an audit of three weeks in the life of a 16-year-old girl is presented. The paper concludes with a discussion of what remains to be done, with special stress on writing time-use rating structures for other age groups and modifying structures already in existence to reflect the values of particular social groups.