New Zealand’s Exchange Rate Regime, the Collapse of Bretton Woods,and the Twilight of the Sterling Area

How did developing countries adapt to the collapse of the Bretton Woods system? Using new archival evidence, we argue that New Zealand offers an interesting case study of decision-making in a small economy dependent on primary production with close economic and political links to two larger partners – Britain and Australia – with divergent domestic policies. After some experimentation, New Zealand adopted an innovative intermediate solution for the exchange rate that aimed to generate stability for primary producers during a period when the direction of trade was diversifying and most currencies were floating. This imaginative policy was not accompanied by comparable changes in reserves management, and until 1975 New Zealand continued to hold the bulk of its reserves in sterling. The article explores the different priorities and institutional constraints affecting the choice of anchor currency and reserve currency in this context.

Formal Modelling, Testing and Verification of HSA Memory Models using Event-B

The HSA Foundation has produced the HSA Platform System Architecture Specification that goes a long way towards addressing the need for a clear and consistent method for specifying weakly consistent memory. HSA is specified in a natural language which makes it open to multiple ambiguous interpretations and could render bugs in implementations of it in hardware and software. In this paper we present a formal model of HSA which can be used in the development and verification of both concurrent software applications as well as in the development and verification of the HSA-compliant platform itself. We use the Event-B language to build a provably correct hierarchy of models from the most abstract to a detailed refinement of HSA close to implementation level. Our memory models are general in that they represent an arbitrary number of masters, programs and instruction interleavings. We reason about such general models using refinements. Using Rodin tool we are able to model and verify an entire hierarchy of models using proofs to establish that each refinement is correct. We define an automated validation method that allows us to test baseline compliance of the model against a suite of published HSA litmus tests. Once we complete model validation we develop a coverage driven method to extract a richer set of tests from the Event-B model and a user specified coverage model. These tests are used for extensive regression testing of hardware and software systems. Our method of refinement based formal modelling, baseline compliance testing of the model and coverage driven test extraction using the single language of Event-B is a new way to address a key challenge facing the design and verification of multi-core systems.Comment: 9 pages, 10 figure

Broken promise of mobility, The: higher education's funding impact on poverty and college debt

2021 Spring.Includes bibliographical references.Following findings of increased poverty over time among Coloradans with college experience, I estimate the impact of Higher Education spending on poverty and debt outcomes for groups of individuals who have completed at least their post-secondary bachelor's degree. I hypothesize that the current level of Higher Education funding at the state level has contributed to the growing poverty and student debt. Using regression models with state and year fixed effects for poverty and additional institution-level fixed effects for debt, I find that an increase of $1 in spending on per capita Higher Education would reduce poverty by 0.03$1.18 per student each year. The reduction in debt per student would be both proactive in reducing future debt and contribute to reducing current debt every fiscal cycle. Additionally, the relationship between debt and state spending indicates that growth in GDP and median income would reduce both the poverty rate and personal debt for college graduates. The impact of state supports on debt, in particular, validates the hypothesis that state spending on post-secondary institutions is currently failing to address the shifting cost-benefit value of a degree

Spectral properties of the nonspherically decaying radiation generated by a rotating superluminal source

The focusing of the radiation generated by a polarization current with a superluminally rotating distribution pattern is of a higher order in the plane of rotation than in other directions. Consequently, our previously published asymptotic approximation to the value of this field outside the equatorial plane breaks down as the line of sight approaches a direction normal to the rotation axis, i.e., is nonuniform with respect to the polar angle. Here we employ an alternative asymptotic expansion to show that, though having a rate of decay with frequency (mu) that is by a factor of order mu^(2/3) slower, the equatorial radiation field has the same dependence on distance as the nonspherically decaying component of the generated field in other directions: it, too, diminishes as the inverse square root of the distance from its source. We also briefly discuss the relevance of these results to the giant pulses received from pulsars: the focused, nonspherically decaying pulses that arise from a superluminal polarization current in a highly magnetized plasma have a power-law spectrum (i.e., a flux density proportional to mu^alpha) whose index (alpha) is given by one of the values -2/3, -2, -8/3, or -4

Inferring Concise Specifications of APIs

Modern software relies on libraries and uses them via application programming interfaces (APIs). Correct API usage as well as many software engineering tasks are enabled when APIs have formal specifications. In this work, we analyze the implementation of each method in an API to infer a formal postcondition. Conventional wisdom is that, if one has preconditions, then one can use the strongest postcondition predicate transformer (SP) to infer postconditions. However, SP yields postconditions that are exponentially large, which makes them difficult to use, either by humans or by tools. Our key idea is an algorithm that converts such exponentially large specifications into a form that is more concise and thus more usable. This is done by leveraging the structure of the specifications that result from the use of SP. We applied our technique to infer postconditions for over 2,300 methods in seven popular Java libraries. Our technique was able to infer specifications for 75.7% of these methods, each of which was verified using an Extended Static Checker. We also found that 84.6% of resulting specifications were less than 1/4 page (20 lines) in length. Our technique was able to reduce the length of SMT proofs needed for verifying implementations by 76.7% and reduced prover execution time by 26.7%