Tight Bounds for Connectivity and Set Agreement in Byzantine Synchronous Systems

In this paper, we show that the protocol complex of a Byzantine synchronous system can remain $(k - 1)$-connected for up to $\lceil t/k \rceil$ rounds, where $t$ is the maximum number of Byzantine processes, and $t \ge k \ge 1$. This topological property implies that $\lceil t/k \rceil + 1$ rounds are necessary to solve $k$-set agreement in Byzantine synchronous systems, compared to $\lfloor t/k \rfloor + 1$ rounds in synchronous crash-failure systems. We also show that our connectivity bound is tight as we indicate solutions to Byzantine $k$-set agreement in exactly $\lceil t/k \rceil + 1$ synchronous rounds, at least when $n$ is suitably large compared to $t$. In conclusion, we see how Byzantine failures can potentially require one extra round to solve $k$-set agreement, and, for $n$ suitably large compared to $t$, at most that

Taxes, Inequality and the Size of the Informal Sector

In this note we develop a simple heterogeneous-agent model with incomplete markets to explain the prevalence of a large, low-productivity, informal sector in developing countries. In our models, taxes levied on formal sector agents are used to finance the provision of a productive public infrastructure, which creates a productivity premium from formalization. Our model offers endogenous differentiation of rich and poor countries. Complete formalization is an equilibrium only in countries with the appropriate initial conditions. We discuss existence of this equilibrium and highlight the ambiguous effect of taxes.Informal sector, Technology adoption, Infrastructure, Inequality, Taxation, Development

A novel qualitative prospective methodology to assess human error during accident sequences

Numerous theoretical models and techniques to assess human error were developed since the 60's. Most of these models were developed for the nuclear, military, and aviation sectors. These methods have the following weaknesses that limit their use in industry: the lack of analysis of underlying causal cognitive mechanisms, need of retrospective data for implementation, strong dependence on expert judgment, focus on a particular type of error, and/or analysis of operator behaviour and decision-making without considering the role of the system in such decisions. The purpose of the present research is to develop a qualitative prospective methodology that does not depend exclusively on retrospective information, that does not require expert judgment for implementation and that allows predicting potential sequences of accidents before they occur. It has been proposed for new (or existent) small and medium- scale facilities, whose processes are simple. To the best of our knowledge, a methodology that meets these requirements has not been reported in literature thus far. The methodology proposed in this study was applied to the methanol storage area of a biodiesel facility. It could predict potential sequences of accidents, through the analysis of information provided by different system devices and the study of the possible deviations of operators in decision-making. It also enabled the identification of the shortcomings in the human-machine interface and proposed an optimization of the current configuration.Fil: Calvo Olivares, Romina Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; ArgentinaFil: Rivera, Selva Soledad. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; ArgentinaFil: Núñez Mc Leod, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingenieria. Instituto de Capacitación Especial y Desarrollo de Ingeniería Asistida por Computadora; Argentin

Attitudes on Medical Ethics of Criminal Neurointerventional Treatment

As contemporary scientific advancements offer the opportunity to manipulate processes of the human body at a higher degree of invasiveness than ever before, a number of bioethical concerns are raised. One significant concern is how to discern the acceptable integration of advancements in neurologically-based interventions into the criminal justice system. Past literature supports the idea that there are several variables that interact to form a global conversation on the ethics of compromising a criminal’s freedom of mind for the purposes of sentencing or rehabilitation. Attitudes toward the current criminal justice system and the current uses of neurointerventions are significantly influential, and the public attitudes of such topics have been well-recorded through the literature. An experienced physician was interviewed in order to gain the perspective of a professional who regularly implements neurologically-based treatments. The results of the interview suggested that professionals have a moderate level of confidence that the current relationship between the criminal justice system and neurointerventional methods has generally remained within ethical boundaries. The results also suggested that medical practitioners are tasked with balancing the dignity and the safety patients, which can cause frequent ethical dilemmas. The varying responsibilities of medical professionals keep them equipped to implement expert-level care while simultaneously considering the ethical ramifications of their decisions

Failure and Strategic Projects: Australias Asia-Pacific Vision

This paper uses Australia’s 1980s shift to a new accumulation strategy of ‘international competitiveness’ to examine the role of failure in shaping state strategic projects. The paper argues that the Australian strategy’s gradual shift from an interventionist to a market-led orientation played out in competing representations of failure. Whether particular policies were perceived as failures depended not only on their material effects, but also on the ways in which failure was defined and on the values underpinning those definitions. As representations of failure establish the boundaries between the incremental adaptations that stabilise an accumulation strategy and the more radical failures characteristic of crisis, they illuminate how processes of discursive selectivity ‘fix’ state projects’ temporal, scalar and spatial dimension

Long-Term Preservation of Digital Records, Part I: A Theoretical Basis

The Information Revolution is making preservation of digital records an urgent issue. Archivists have grappled with the question of how to achieve this for about 15 years. We focus on limitations to preservation, identifying precisely what can be preserved and what cannot. Our answer comes from the philosophical theory of knowledge, especially its discussion about the limits of what can be communicated. Philosophers have taught that answers to critical questions have been obscured by "failure to understand the logic of our language". We can clarify difficulties by paying extremely close attention to the meaning of words such as 'knowledge', 'information', 'the original', and 'dynamic'. What is valuable in transmitted and stored messages, and what should be preserved, is an abstraction, the pattern inherent in each transmitted and stored digital record. This answer has, in fact, been lurking just below the surface of archival literature. To make progress, archivists must collaborate with software engineers. Understanding perspectives across disciplinary boundaries will be needed.

Institutions and Policies Shaping Industrial Development: An Introductory Note

In this work, meant as an introduction to the contributions of the task force on Industrial Policies and Development, Initiative for Policy Dialogue, Columbia University, New York, we discuss the role of institutions and policies in the process of development. We begin by arguing how misleading the "market failure" language can be in order to assess the necessity of public policies in that it evaluates it against a yardstick that is hardly met by any observed market set-up. Much nearer to the empirical evidence we argue that even when one encounters a prevailing market form of governance of economic interactions, the latter are embedded in a rich thread of non-market institutions. This applies in general and is particularly so with respect to the production and use of information and technological knowledge. In this work we build on the fundamental institutional embeddedness of such processes of technological learning in both developed and catching-up countries and we try to identify some quite robust policy ingredients which have historically accompanied the co-evolution between technological capabilities, forms of corporate organisations and incentive structures. All experiences of successful catching-up and sometimes overtaking the incumbent economic leaders – starting with the USA vis-à-vis Britain – have involved “institution building” and policy measures affecting technological imitation, the organisations of industries, trade patterns and intellectual property rights. This is likely to apply today, too, – we argue – also in the context of a “globalised” world economy.Institutions, development, industrial policies, technological catching-up, trade specialisations.