k-Step Relative Inductive Generalization

We introduce a new form of SAT-based symbolic model checking. One common idea in SAT-based symbolic model checking is to generate new clauses from states that can lead to property violations. Our previous work suggests applying induction to generalize from such states. While effective on some benchmarks, the main problem with inductive generalization is that not all such states can be inductively generalized at a given time in the analysis, resulting in long searches for generalizable states on some benchmarks. This paper introduces the idea of inductively generalizing states relative to $k$-step over-approximations: a given state is inductively generalized relative to the latest $k$-step over-approximation relative to which the negation of the state is itself inductive. This idea motivates an algorithm that inductively generalizes a given state at the highest level $k$ so far examined, possibly by generating more than one mutually $k$-step relative inductive clause. We present experimental evidence that the algorithm is effective in practice.Comment: 14 page

Third-Party Intervention and the Preservation of Bargaining Relationships

This article uses longitudinal contact data to examine if third-party dispute resolution procedures available in Ontario improve the health of bargaining relationships and contribute to their preservation. It performs this in two manners: (1) using survival analysis to see how the mechanisms correlate with the likelihood of relationship dissolution and (2) using dynamic panel models to observe their state dependence. The latter is undertaken to see if third-party intervention pushes the parties to settle subsequent agreements earlier in the process – a finding that would reveal another aspect of relationship preservation if those earlier interventions are shown to correlate with lower likelihoods of dissolution. While the survival analysis does show that the earlier procedures in the dispute resolution process associate with lower likelihoods of dissolution than later ones, the dynamic panel model estimates do not indicate that third-party intervention induces voluntary or even earlier settlements in subsequent rounds of bargaining

Fluid passage-time calculation in large Markov models

Recent developments in the analysis of large Markov models facilitate the fast approximation of transient characteristics of the underlying stochastic process. So-called fluid analysis makes it possible to consider previously intractable models whose underlying discrete state space grows exponentially as model components are added. In this work, we show how fluid approximation techniques may be used to extract passage-time measures from performance models. We focus on two types of passage measure: passage-times involving individual components; as well as passage-times which capture the time taken for a population of components to evolve. Specifically, we show that for models of sufficient scale, passage-time distributions can be well approximated by a deterministic fluid-derived passage-time measure. Where models are not of sufficient scale, we are able to generate approximate bounds for the entire cumulative distribution function of these passage-time random variables, using moment-based techniques. Finally, we show that for some passage-time measures involving individual components the cumulative distribution function can be directly approximated by fluid techniques

The Last Full Measure of Devotion : The Battle of Gettysburg and the New Museum in Schmucker Hall

Schmucker Hall offers an unprecedented opportunity to interpret the role of religion in the Civil War and the American expenment in democracy. In particular it can give palpable expression to major themes in Abraham Lincoln\u27s Gettysburg Address concerning the battle itself, the conflict as a time of testing, the sacrifices of those who fought here, and the hope these sacrifices bring to the young nation for a new birth of freedom. Built in 1832 and named for an abolitionist and founder of Gettysburg Seminary, Samuel Simon Schmucker, it is the original structure on the oldest continuously-operating Lutheran seminary in the United States, and many say it IS the most significant Civil War building in America still in private hands. Thus, Gettysburg Seminary has a place and it has a man to interpret significant aspects of the Civil War in ways that no other museum, including a government agency such as the National Park Service (NPS), can do. [excerpt

Treaty Exit in the United States: Insights from the United Kingdom or South Africa?

This essay, a contribution to an AJIL Unbound symposium on “Treaty Exit at the Interface of Domestic and International Law,” compares treaty exit in the United States, the United Kingdom, and South Africa. After examining the longstanding practice of unilateral presidential withdrawals from treaties in the United States and the refusal to date of U.S. courts to review the constitutionality of that practice, the essay summarizes recent judicial decisions in the United Kingdom and South Africa holding that parliamentary approval was required before these nations could withdraw from treaties committing them, respectively, to the European Union and the International Criminal Court. We conclude that these decisions—while important and interesting in their own right—offer limited insights for debates in the United States over whether the President has unilateral treaty withdrawal authority and how such withdrawals might affect statutes implementing international agreements

Development of a novel metastable composite material

The development of a new family of mouldable metastable composite materials has been demonstrated. Their special quality is derived from the ability to maintain the matrix as a supercooled liquid or gel whose solidification can be triggered mechanically, as desired, by a user. This article describes some aspects of the development work. In particular, the following are explained: the choice of matrix material; the use of additives to enhance the properties of the matrix; and the selection of reinforcement fibre. As part of the work, some mechanical testing was performed on several variations of a matrix-fibre pair and, to demonstrate the potential of such materials, some comparisons were made with a possible competitor material, a glass-reinforced urethane. It was shown that the metastable material could be formulated to provide mechanical properties that would make it suitable for applications such as orthopaedic casting, splinting and body armour, and in items of sports equipment, these being areas where its mouldability could be particularly desirable