title: Adversarial risk analysis for first-price sealed-bid auctions

authors: Ejaz, Muhammad

subjects: Adversarial risk analysis

abstract: First-price sealed-bid (FPSB) auctions have mostly been modelled in auction theory using the decision-theoretic and Bayesian game-theoretic approaches. From a practical point of view, each approach has its limitations. To overcome those limitations, Rios Insua et al. (2009) introduced an approach, called adversarial risk analysis (ARA) that provides an optimal solution for one of the intervening agents, based on a decision making problem in hand and treating the intelligent adversaries' decisions as uncertainties. ARA solutions for FPSB auctions have previously been found but only under strong assumptions which make the model somewhat unrealistic.
In this thesis, we use ARA methodology and model bidders' behaviours in FPSB auctions using more realistic assumptions. First, we model bidders' behaviours by defining a new utility function that considers bidders' wealth which is assumed to be different for each bidder. We consider bidders' wealth since it is a significant determinant of their bidding behaviour in these auctions. Also, we define new risk behaviour parameters that change with the relative change in circumstances of bidders' wealth. In our modelling, we assume that the auctioned item is normal and has a reserve price which is known in advance to each bidder. We find ARA solutions not only for risk-neutral but also for risk-averse as well as risk-seeking bidders. We model these auctions by ARA framework using non-strategic play, level-k thinking, mirror equilibrium (ME) and Bayes Nash equilibrium (BNE) solution concepts. Finding ARA solutions using non-strategic play and level-k thinking, ME and BNE (asymmetric case) solution concepts, we assume two bidders. Whereas, we assume n bidders while finding ARA solutions using BNE symmetric case.
Second, we use ARA methodology and model bidders' behaviours using the utility function that takes into account bidders' winning and losing regret for the auctioned item. We define new winning and losing regret parameters and a modified utility function in order to take into account the effect of bidders' wealth on their bidding behaviours. Using the modified utility function, we find ARA solutions using non-strategic play and level-k thinking solution concepts assuming n bidders participating in these auctions. 
We give numerical examples to illustrate our methodology.

text: Adversarial risk analysis for first-price sealed-bid auctions First-price sealed-bid (FPSB) auctions have mostly been modelled in auction theory using the decision-theoretic and Bayesian game-theoretic approaches. From a practical point of view, each approach has its limitations. To overcome those limitations, Rios Insua et al. (2009) introduced an approach, called adversarial risk analysis (ARA) that provides an optimal solution for one of the intervening agents, based on a decision making problem in hand and treating the intelligent adversaries' decisions as uncertainties. ARA solutions for FPSB auctions have previously been found but only under strong assumptions which make the model somewhat unrealistic.
In this thesis, we use ARA methodology and model bidders' behaviours in FPSB auctions using more realistic assumptions. First, we model bidders' behaviours by defining a new utility function that considers bidders' wealth which is assumed to be different for each bidder. We consider bidders' wealth since it is a significant determinant of their bidding behaviour in these auctions. Also, we define new risk behaviour parameters that change with the relative change in circumstances of bidders' wealth. In our modelling, we assume that the auctioned item is normal and has a reserve price which is known in advance to each bidder. We find ARA solutions not only for risk-neutral but also for risk-averse as well as risk-seeking bidders. We model these auctions by ARA framework using non-strategic play, level-k thinking, mirror equilibrium (ME) and Bayes Nash equilibrium (BNE) solution concepts. Finding ARA solutions using non-strategic play and level-k thinking, ME and BNE (asymmetric case) solution concepts, we assume two bidders. Whereas, we assume n bidders while finding ARA solutions using BNE symmetric case.
Second, we use ARA methodology and model bidders' behaviours using the utility function that takes into account bidders' winning and losing regret for the auctioned item. We define new winning and losing regret parameters and a modified utility function in order to take into account the effect of bidders' wealth on their bidding behaviours. Using the modified utility function, we find ARA solutions using non-strategic play and level-k thinking solution concepts assuming n bidders participating in these auctions. 
We give numerical examples to illustrate our methodology.

year: 2021

title: Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka

authors: Karlstrom, KE

abstract: This paper hypothesizes that the Meteor Crater impact in Arizona, USA, 56,000 years ago triggered landslides in Grand Canyon that dammed the Colorado River and formed Nankoweap paleolake. This is compatible with shock and earthquake physics for the impact that infer a M5.4 seismic event, attenuated to an effective magnitude of M3.5 at Grand Canyon. Results that support the hypothesis include radiocarbon dating of driftwood and luminescence dating of associated slack-water lake sediments that are preserved in caves up to 60 m above the modern Colorado River. Radiocarbon ages from two locations, including Stanton’s Cave, date the driftwood as 55.25 ± 2.44 ka (n = 4). Sediments associated with the driftwood gave a luminescence age of 56.00 ± 6.39 ka (n = 2). These six Grand Canyon dates, and three published ages for the Meteor Crater impact, show statistically indistinguishable results that support the hypothesis for a geologically instantaneous series of events with a mean age of 55.60 ± 1.30 ka. This work highlights the value of radiocarbon dating near the limits of the technique, integration of multiple dating methods, and seismic and landslide hazards associated with meteorite impacts in regions of extreme topography like Grand Canyon.

text: Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka This paper hypothesizes that the Meteor Crater impact in Arizona, USA, 56,000 years ago triggered landslides in Grand Canyon that dammed the Colorado River and formed Nankoweap paleolake. This is compatible with shock and earthquake physics for the impact that infer a M5.4 seismic event, attenuated to an effective magnitude of M3.5 at Grand Canyon. Results that support the hypothesis include radiocarbon dating of driftwood and luminescence dating of associated slack-water lake sediments that are preserved in caves up to 60 m above the modern Colorado River. Radiocarbon ages from two locations, including Stanton’s Cave, date the driftwood as 55.25 ± 2.44 ka (n = 4). Sediments associated with the driftwood gave a luminescence age of 56.00 ± 6.39 ka (n = 2). These six Grand Canyon dates, and three published ages for the Meteor Crater impact, show statistically indistinguishable results that support the hypothesis for a geologically instantaneous series of events with a mean age of 55.60 ± 1.30 ka. This work highlights the value of radiocarbon dating near the limits of the technique, integration of multiple dating methods, and seismic and landslide hazards associated with meteorite impacts in regions of extreme topography like Grand Canyon.

year: 2025

title: Typographic design in Māori-English bilingual picturebooks: some educational implications

authors: Vanderschantz, Nicholas

subjects: Te Reo Māori

abstract: The role of bilingual picturebooks in language learning has been explored recently by a number of authors who show their potential in normalising multilingualism (Naqvi, Thorne, Pfitscher, Nordstokke & McKeough, 2013; Zaidi, 2020), raising metalinguistic awareness and engaging parents (Sneddon, 2009), as well as raising language awareness (Kleker, Short & Daly, 2021). Hadaway and Young (2013) suggest bilingual picturebooks have a particular role to play in supporting the revitalisation of Indigenous languages. In New Zealand, the number of MāoriEnglish bilingual picturebooks is increasing, but there is very little, if any, research concerning their design or their use in educational settings. The design of bilingual picturebooks, as reflected in their linguistic landscape, has an important role to play in their pedagogical use (Daly, 2016; 2017), and in this article, we explore the typographic design of five bilingual Māori-English picturebooks with respect to the elements of typeface, type size, type colour and page layout. We discuss the design and audience implications of these factors for educational settings.

text: Typographic design in Māori-English bilingual picturebooks: some educational implications The role of bilingual picturebooks in language learning has been explored recently by a number of authors who show their potential in normalising multilingualism (Naqvi, Thorne, Pfitscher, Nordstokke & McKeough, 2013; Zaidi, 2020), raising metalinguistic awareness and engaging parents (Sneddon, 2009), as well as raising language awareness (Kleker, Short & Daly, 2021). Hadaway and Young (2013) suggest bilingual picturebooks have a particular role to play in supporting the revitalisation of Indigenous languages. In New Zealand, the number of MāoriEnglish bilingual picturebooks is increasing, but there is very little, if any, research concerning their design or their use in educational settings. The design of bilingual picturebooks, as reflected in their linguistic landscape, has an important role to play in their pedagogical use (Daly, 2016; 2017), and in this article, we explore the typographic design of five bilingual Māori-English picturebooks with respect to the elements of typeface, type size, type colour and page layout. We discuss the design and audience implications of these factors for educational settings.

year: 2022