Comparison of Gaussian process modeling software

Gaussian process fitting, or kriging, is often used to create a model from a set of data. Many available software packages do this, but we show that very different results can be obtained from different packages even when using the same data and model. We describe the parameterization, features, and optimization used by eight different fitting packages that run on four different platforms. We then compare these eight packages using various data functions and data sets, revealing that there are stark differences between the packages. In addition to comparing the prediction accuracy, the predictive variance--which is important for evaluating precision of predictions and is often used in stopping criteria--is also evaluated

The normativity of code as law: towards input legitimacy

In the debate on how the new information and communication technologies impact on democratic politics the role played by the digital architecture seems to be surprisingly underrated. In particular, while a lot of attention has been paid to the possibilities that new technologies open up to democratic theory, few works have attempted to look at how democracy may help in shaping technologies. By adopting as a starting point the approach known as ‘code as law’, the paper aims at two objectives: to re-affirm the importance of discussing normative principles to guide the process of code writing in order to reinvigorate the debate; to claim the importance of input reasons when deciding which principles should be chosen. After having remarked that code is relevant for establishing democratic norms, the paper briefly tackles with the main attempts by European scholars to deal with this issue. Then, a couple of practical examples of how code impacts on democratic rights are sketched out. In the last section of the paper a shift from an output-based approach to the legitimacy of code to an input-based is openly advocated: an inquiry into the legitimacy of code should focus on its production

Causes, consequences, and cures of myopic loss aversion - An experimental investigation

Myopic loss aversion (MLA) has been established as one prominent explanation for the equity premium puzzle. In this paper we address two issues related to the effects of MLA on risky investment decisions. First, we assess the relative impact of feedback frequency and investment flexibility (via the investment horizon) on risky investments. Second, given that we observe higher investments with a longer investment horizon, we examine conditions under which investors might endogenously opt for a longer investment horizon in order to avoid the negative effects of MLA on investments. We find in our experimental study that investment flexibility seems to be at least as relevant as feedback frequency for the effects of myopic loss aversion. When subjects are given the choice to opt for a long or short investment horizon, there is no clear preference for either. Yet, if subjects face a default horizon (either long or short), there is rather little switching from the one to the other horizon, showing that a default might work to attenuate the effects of MLA. However, if subjects switch, they are more often willing to switch from the long to the short horizon than vice versa, suggesting a preference for higher investment flexibility

Two paradigms for religious representation: The physicist and the playground

In an earlier issue, I argue (2014) that psychology and epistemology should distinguish religious credence from factual belief. These are distinct cognitive attitudes. Levy (2017) rejects this distinction, arguing that both religious and factual “beliefs” are subject to “shifting” on the basis of fluency and “intuitiveness.” Levy’s theory, however, (1) is out of keeping with much research in cognitive science of religion and (2) misrepresents the notion of factual belief employed in my theory. So his claims don’t undermine my distinction. I conclude by suggesting some approaches to empirically testing our views

Religious Pluralism and the Buridan's Ass Paradox

The paradox of ’Buridan’s ass’ involves an animal facing two equally adequate and attractive alternatives, such as would happen were a hungry ass to confront two bales of hay that are equal in all respects relevant to the ass’s hunger. Of course, the ass will eat from one rather than the other, because the alternative is to starve. But why does this eating happen? What reason is operative, and what explanation can be given as to why the ass eats from, say, the left bale rather than the right bale? Why doesn’t the ass remain caught between the options, forever indecisive and starving to death? Religious pluralists face a similar dilemma, a dilemma that I will argue is more difficult to address than the paradox just describe

The Impact of Default Dependency and Collateralization on Asset Pricing and Credit Risk Modeling

This article presents a comprehensive framework for valuing financial instruments subject to credit risk and collateralization. In particular, we focus on the impact of default dependence on asset pricing, as correlated default risk is one of the most pervasive threats to financial markets. Some well-known risky valuation models in the markets can be viewed as special cases of this framework. We introduce the concept of comvariance (or comrelation) into the area of credit risk modeling to capture the default relationship among three or more parties. Accounting for default correlations and comrelations becomes important, especially during the credit crisis. Moreover, we find that collateralization works well for financial instruments subject to bilateral credit risk, but fails for ones subject to multilateral credit risk

Bringing Web Time Travel to MediaWiki: An Assessment of the Memento MediaWiki Extension

We have implemented the Memento MediaWiki Extension Version 2.0, which brings the Memento Protocol to MediaWiki, used by Wikipedia and the Wikimedia Foundation. Test results show that the extension has a negligible impact on performance. Two 302 status code datetime negotiation patterns, as defined by Memento, have been examined for the extension: Pattern 1.1, which requires 2 requests, versus Pattern 2.1, which requires 3 requests. Our test results and mathematical review find that, contrary to intuition, Pattern 2.1 performs better than Pattern 1.1 due to idiosyncrasies in MediaWiki. In addition to implementing Memento, Version 2.0 allows administrators to choose the optional 200-style datetime negotiation Pattern 1.2 instead of Pattern 2.1. It also permits administrators the ability to have the Memento MediaWiki Extension return full HTTP 400 and 500 status codes rather than using standard MediaWiki error pages. Finally, version 2.0 permits administrators to turn off recommended Memento headers if desired. Seeing as much of our work focuses on producing the correct revision of a wiki page in response to a user's datetime input, we also examine the problem of finding the correct revisions of the embedded resources, including images, stylesheets, and JavaScript; identifying the issues and discussing whether or not MediaWiki must be changed to support this functionality.Comment: 23 pages, 18 figures, 9 tables, 17 listing

How Strongly Should We Protect and Enforce International Law?, University of Chicago Law School Workshop, March 2006

Observers of international law are obsessed with trying to explain and predict why and when states comply with international law. Doing so, they have consistently overlooked a logically preceding, but no less important, question: To what extent should states perform their international commitments? Put differently, how strongly should we protect and enforce international law? Worrying as much about over-enforcement of international law as under-enforcement of international law, this article offers a theory of relative normativity. This theory is driven by efficiency, effectiveness and legitimacy concerns rather than a hierarchy of values. It makes distinctions between how international law allocates entitlements, how it protects entitlements and how it reacts when rules of protection are broken (back-up enforcement). My central claim is that, much like domestic law, international law is best protected on a sliding scale between strict inalienability and simple liability. From that perspective, both what I call European \u27absolutism\u27 and American \u27voluntarism\u27 must be avoided as extreme and homogeneous normative frameworks

In conversation with Professor Jonathan Rix

Professor ‘Jonty’ Rix holds the chair of Participation and Learning Support at the Open University. Jonty's research interests include policies, practices and language that facilitates inclusion. His work explores diverse perspectives and models that promote thinking about the aim and fundamental purpose of education which is central to his philosophy …. ‘it’s not just about changing systems’ (Rix, 2016). I had the opportunity of spending a couple of very enjoyable hours ‘in conversation’ with Professor Rix. The aim was to discuss his latest book, ‘Must Inclusion be Special?’ but our discussion quickly moved into an interesting exploration of his realistic vision for educational change which I endeavour to capture here along with offering some insights into his book