title: The marginal willingness-to-pay for attributes of a hypothetical HIV vaccine

authors: Cameron, Michael Patrick

subjects: HIV vaccine

abstract: This paper estimates the marginal willingness-to-pay for attributes of a hypothetical HIV vaccine using discrete choice modeling. We use primary data from 326 respondents from Bangkok and Chiang Mai, Thailand, in 2008–2009, selected using purposive, venue-based sampling across two strata. Participants completed a structured questionnaire and full rank discrete choice modeling task administered using computer-assisted personal interviewing. The choice experiment was used to rank eight hypothetical HIV vaccine scenarios, with each scenario comprising seven attributes (including cost) each of which had two levels. The data were analyzed in two alternative specifications: (1) best-worst; and (2) full-rank, using logit likelihood functions estimated with custom routines in Gauss matrix programming language. In the full-rank specification, all vaccine attributes are significant predictors of probability of vaccine choice. The biomedical attributes of the hypothetical HIV vaccine (efficacy, absence of VISP, absence of side effects, and duration of effect) are the most important attributes for HIV vaccine choice. On average respondents are more than twice as likely to accept a vaccine with 99% efficacy, than a vaccine with 50% efficacy. This translates to a willingness to pay US$383 more for a high efficacy vaccine compared with the low efficacy vaccine. Knowledge of the relative importance of determinants of HIV vaccine acceptability is important to ensure the success of future vaccination programs. Future acceptability studies of hypothetical HIV vaccines should use more finely grained biomedical attributes, and could also improve the external validity of results by including more levels of the cost attribute.

text: The marginal willingness-to-pay for attributes of a hypothetical HIV vaccine This paper estimates the marginal willingness-to-pay for attributes of a hypothetical HIV vaccine using discrete choice modeling. We use primary data from 326 respondents from Bangkok and Chiang Mai, Thailand, in 2008–2009, selected using purposive, venue-based sampling across two strata. Participants completed a structured questionnaire and full rank discrete choice modeling task administered using computer-assisted personal interviewing. The choice experiment was used to rank eight hypothetical HIV vaccine scenarios, with each scenario comprising seven attributes (including cost) each of which had two levels. The data were analyzed in two alternative specifications: (1) best-worst; and (2) full-rank, using logit likelihood functions estimated with custom routines in Gauss matrix programming language. In the full-rank specification, all vaccine attributes are significant predictors of probability of vaccine choice. The biomedical attributes of the hypothetical HIV vaccine (efficacy, absence of VISP, absence of side effects, and duration of effect) are the most important attributes for HIV vaccine choice. On average respondents are more than twice as likely to accept a vaccine with 99% efficacy, than a vaccine with 50% efficacy. This translates to a willingness to pay US$383 more for a high efficacy vaccine compared with the low efficacy vaccine. Knowledge of the relative importance of determinants of HIV vaccine acceptability is important to ensure the success of future vaccination programs. Future acceptability studies of hypothetical HIV vaccines should use more finely grained biomedical attributes, and could also improve the external validity of results by including more levels of the cost attribute.

year: 2013

title: Using context to solve the correspondence problem in Simultaneous Localisation and Mapping

authors: Jefferies, Margaret E.

subjects: computer science

abstract: We present a method for solving the correspondence problem in Simultaneous Localisation and Mapping (SLAM) in a topological map. The nodes in the topological map are a representation for each local space the robot visits. The approach is feature based - a neural network algorithm is used to learn a signature from a set of features extracted from each local space representation. Newly encountered local spaces are classified by the neural network as to how well they match the signatures of the nodes in the topological network. Of equal importance as the correspondence problem is its dual, that of perceptual aliasing which occurs when parts of the environment which appear the same are in fact different. It manifests itself as false positive matches from the neural network classification. Our approach to solving this aspect of the problem is to use the context provide by nodes in the neighbourhood of the (mis)matched node. When neural network classification indicates a correspondence then subsequent local spaces the robot visits should also match nodes in the topological map where appropriate.

text: Using context to solve the correspondence problem in Simultaneous Localisation and Mapping We present a method for solving the correspondence problem in Simultaneous Localisation and Mapping (SLAM) in a topological map. The nodes in the topological map are a representation for each local space the robot visits. The approach is feature based - a neural network algorithm is used to learn a signature from a set of features extracted from each local space representation. Newly encountered local spaces are classified by the neural network as to how well they match the signatures of the nodes in the topological network. Of equal importance as the correspondence problem is its dual, that of perceptual aliasing which occurs when parts of the environment which appear the same are in fact different. It manifests itself as false positive matches from the neural network classification. Our approach to solving this aspect of the problem is to use the context provide by nodes in the neighbourhood of the (mis)matched node. When neural network classification indicates a correspondence then subsequent local spaces the robot visits should also match nodes in the topological map where appropriate.

year: 2004

title: Lifting barriers: Leadership, tactical, and strategic issues from, and for, indigenous community development

authors: Murthy, Vikram

subjects: indigenous communities

abstract: This paper uses learnings from a project with indigenous youth to engage with a recurring challenge in indigenous community organisation (ICO) development initiatives: The unwitting detraction from outcome efficacy by charismatic and influential indigenous leadership leading with an out-of-date repertoire. Using material from recent literature in the fields of non-profit management, new leadership, and social enterprise, the paper suggests guides to improved practice for meeting this challenge. It also sets out to effectiveness, will better underwrite sensitivity in entrepreneurial environments with complex cultural and social beliefs and practices. Such a repertoire will energise intraorganisational communal and consensual processes, which would resonate culturally with the ICO's normative behaviours and values, and would thus help the organisation marshall its collective will to frame futures that best capture their stakeholders' hopes and aspirations. Finally, it recommends that future research examine interfaces between these fields and the spiritual frameworks of indigenous world-views.

text: Lifting barriers: Leadership, tactical, and strategic issues from, and for, indigenous community development This paper uses learnings from a project with indigenous youth to engage with a recurring challenge in indigenous community organisation (ICO) development initiatives: The unwitting detraction from outcome efficacy by charismatic and influential indigenous leadership leading with an out-of-date repertoire. Using material from recent literature in the fields of non-profit management, new leadership, and social enterprise, the paper suggests guides to improved practice for meeting this challenge. It also sets out to effectiveness, will better underwrite sensitivity in entrepreneurial environments with complex cultural and social beliefs and practices. Such a repertoire will energise intraorganisational communal and consensual processes, which would resonate culturally with the ICO's normative behaviours and values, and would thus help the organisation marshall its collective will to frame futures that best capture their stakeholders' hopes and aspirations. Finally, it recommends that future research examine interfaces between these fields and the spiritual frameworks of indigenous world-views.

year: 2006