title: Constructing (0,1)-matrices with large minimal defining sets

authors: Cavenagh, Nicholas J.

subjects: Science & Technology

abstract: If D is a partially filled-in (0, 1)-matrix with a unique completion to a (0, 1)-matrix M (with prescribed row and column sums), we say that D is a defining set for M. Let A₂ₘ,ₘbe the set of (0, 1)-matrices of dimensions 2m×2m with uniform row and column sum m. It is shown in (Cavenagh, 2013) that the smallest possible size for a defining set of an element of A₂ₘ,ₘ is precisely m². In this note when m is a power of two we construct an element of A₂ₘ,ₘ  which has no defining set of size less than 2m² − o(m²). Given that it is easy to show any A₂ₘ,ₘ  has a defining set of size at most 2m², this construction is asymptotically optimal. Our construction is based on a array, defined using linear algebra, in which any subarray has asymptotically the same number of 0’s and 1’s.

text: Constructing (0,1)-matrices with large minimal defining sets If D is a partially filled-in (0, 1)-matrix with a unique completion to a (0, 1)-matrix M (with prescribed row and column sums), we say that D is a defining set for M. Let A₂ₘ,ₘbe the set of (0, 1)-matrices of dimensions 2m×2m with uniform row and column sum m. It is shown in (Cavenagh, 2013) that the smallest possible size for a defining set of an element of A₂ₘ,ₘ is precisely m². In this note when m is a power of two we construct an element of A₂ₘ,ₘ  which has no defining set of size less than 2m² − o(m²). Given that it is easy to show any A₂ₘ,ₘ  has a defining set of size at most 2m², this construction is asymptotically optimal. Our construction is based on a array, defined using linear algebra, in which any subarray has asymptotically the same number of 0’s and 1’s.

year: 2018

title: Sparkling wine choice from supermarket shelves: the impact of certification of origin and production practices

authors: Thiene, Mara

subjects: Consumer preferences

abstract: We report the results of a study based on revealed and stated preference data on choice of Prosecco wines in retail stores close to the origin of production in Northern Italy. Emphasis is placed on ability to reconcile the utility structure of stated preference data with that underlying revealed preference data. We extend the analysis to cover nonattendance of key attributes, such as price and certification of origin, while controlling for the large range of brand effects.

text: Sparkling wine choice from supermarket shelves: the impact of certification of origin and production practices We report the results of a study based on revealed and stated preference data on choice of Prosecco wines in retail stores close to the origin of production in Northern Italy. Emphasis is placed on ability to reconcile the utility structure of stated preference data with that underlying revealed preference data. We extend the analysis to cover nonattendance of key attributes, such as price and certification of origin, while controlling for the large range of brand effects.

year: 2013

title: Missing in translation: Maori language and oral tradition in scientific analyses of traditional ecological knowledge (TEK)

authors: Wehi, Priscilla M.

subjects: Maori language

abstract: Recent conceptual shifts in ecology towards integration of humans into ecosystems requires all possible sources of ecological knowledge available (Berkes 2004, 2009 this issue). Māori traditional ecological knowledge of natural systems (TEK) can add valuable ecological data to more conventional scientific studies as the former tends to be diachronic, based on a cumulative system of understanding the environment founded on observations and experience (Gadgil et al. 1993; Berkes 2008), while the latter is frequently synchronic, with experiments that may explore causal effects in ecological patterns (Newman & Moller 2005; Moller et al. 2009a). However accessing TEK can be both difficult and time-consuming, as demonstrated by the 14-year research project Kia Mau Te Tītī Mo Ake Tonu Atu (the ‘Keep the Tītī Forever’ research project; Moller et al. 2009a). We argue that oral traditions offer a wealth of information that is frequently overlooked, in part because of a lack of knowledge of te reo Māori (the Māori language) and, further, a lack of recognition of the inextricable link between biological and cultural diversity (Maffi 2005).

text: Missing in translation: Maori language and oral tradition in scientific analyses of traditional ecological knowledge (TEK) Recent conceptual shifts in ecology towards integration of humans into ecosystems requires all possible sources of ecological knowledge available (Berkes 2004, 2009 this issue). Māori traditional ecological knowledge of natural systems (TEK) can add valuable ecological data to more conventional scientific studies as the former tends to be diachronic, based on a cumulative system of understanding the environment founded on observations and experience (Gadgil et al. 1993; Berkes 2008), while the latter is frequently synchronic, with experiments that may explore causal effects in ecological patterns (Newman & Moller 2005; Moller et al. 2009a). However accessing TEK can be both difficult and time-consuming, as demonstrated by the 14-year research project Kia Mau Te Tītī Mo Ake Tonu Atu (the ‘Keep the Tītī Forever’ research project; Moller et al. 2009a). We argue that oral traditions offer a wealth of information that is frequently overlooked, in part because of a lack of knowledge of te reo Māori (the Māori language) and, further, a lack of recognition of the inextricable link between biological and cultural diversity (Maffi 2005).

year: 2009