Affine Sessions

Session types describe the structure of communications implemented by channels. In particular, they prescribe the sequence of communications, whether they are input or output actions, and the type of value exchanged. Crucial to any language with session types is the notion of linearity, which is essential to ensure that channels exhibit the behaviour prescribed by their type without interference in the presence of concurrency. In this work we relax the condition of linearity to that of affinity, by which channels exhibit at most the behaviour prescribed by their types. This more liberal setting allows us to incorporate an elegant error handling mechanism which simplifies and improves related works on exceptions. Moreover, our treatment does not affect the progress properties of the language: sessions never get stuck

Experimental Economics: A Revolution in Understanding Behaviour

What is the best compensation package to offer employees? How should choice among investments in pension plans be structured? Should a government use auctions to sell natural resources? Is it possible to design a market to reduce non-point source pollution in Quebec’s watersheds? What holds people back from trying technologies that are completely new to them? Over the last two decades a revolution has occurred in the advancement of our ability to answer questions such as these. This revolution is called experimental economics. Experimental economics is the use of a controlled laboratory environment to understand decisions people make. In an economics experiment, people make decisions in a laboratory. They are paid according to the outcome of their decisions, and their decisions are analyzed to determine the effect of an institutional or environmental change that is being tested. Through the analysis of behaviour in controlled economics experiments, much has been learned about behaviour when outcomes are uncertain: for example, new notions about preferences toward risk and consumption over time have been developed. Much has also been learned about how people behave in strategic environments: for example, bidding behaviour in auctions is better understood, and the strategies people use as they learn how to trust each other have been observed. The purpose of this report is to describe the methodology of experimental economics and to detail its major uses. We will focus on the ability to measure behaviours in a wide variety of situations important to organizations. We will show, with examples from our own work, how feedback between the laboratory and the field can result in new understanding of decisions in an effort to affect the cycle of poverty in a developing country in fundamentally new ways. What is the best compensation package to offer employees? How should choice among investments in pension plans be structured? Should a government use auctions to sell natural resources? Is it possible to design a market to reduce non-point source pollution in Quebec’s watersheds? What holds people back from trying technologies that are completely new to them? Over the last two decades a revolution has occurred in the advancement of our ability to answer questions such as these. This revolution is called experimental economics. Experimental economics is the use of a controlled laboratory environment to understand decisions people make. In an economics experiment, people make decisions in a laboratory. They are paid according to the outcome of their decisions, and their decisions are analyzed to determine the effect of an institutional or environmental change that is being tested. Through the analysis of behaviour in controlled economics experiments, much has been learned about behaviour when outcomes are uncertain: for example, new notions about preferences toward risk and consumption over time have been developed. Much has also been learned about how people behave in strategic environments: for example, bidding behaviour in auctions is better understood, and the strategies people use as they learn how to trust each other have been observed. The purpose of this report is to describe the methodology of experimental economics and to detail its major uses. We will focus on the ability to measure behaviours in a wide variety of situations important to organizations. We will show, with examples from our own work, how feedback between the laboratory and the field can result in new understanding of decisions in an effort to affect the cycle of poverty in a developing country in fundamentally new ways.

Trust, Communication and Contracts: An Experiment

In the one-shot trust or investment game without opportunities for reputation formation or contracting, economic theory predicts no trusting because there is no incentive for trustworthiness. Under these conditions, theory predicts (a) no effect of pre-play communication, and (b) universal preference for moderate cost binding contracts over interacting without contracts. We introduce the opportunities to engage in pre-play communication and to enter binding or non-binding contracts, and find (a) communication increases trusting and trustworthiness, (b) contracts are largely unnecessary for trusting and trustworthy behaviors and are eschewed by many players, and (c) more trusting leads to higher earnings, and (d) both trustors and trustees favor “fair and efficient” proposals over the more unequal proposals predicted by theory.trust game, trust, trustworthiness, reciprocity, commitment, communication. Comparative analysis of agency problems, Production of public goods

CaSPiS: A Calculus of Sessions, Pipelines and Services

Service-oriented computing is calling for novel computational models and languages with well disciplined primitives for client-server interaction, structured orchestration and unexpected events handling. We present CaSPiS, a process calculus where the conceptual abstractions of sessioning and pipelining play a central role for modelling service-oriented systems. CaSPiS sessions are two-sided, uniquely named and can be nested. CaSPiS pipelines permit orchestrating the flow of data produced by different sessions. The calculus is also equipped with operators for handling (unexpected) termination of the partner’s side of a session. Several examples are presented to provide evidence of the flexibility of the chosen set of primitives. One key contribution is a fully abstract encoding of Misra et al.’s orchestration language Orc. Another main result shows that in CaSPiS it is possible to program a “graceful termination” of nested sessions, which guarantees that no session is forced to hang forever after the loss of its partner

The History of Macroeconomics from Keynes’s General Theory to the Present

This paper is a contribution to the forthcoming Edward Elgar Handbook of the History of Economic Analysis volume edited by Gilbert Faccarello and Heinz Kurz. Its aim is to introduce the reader to the main episodes that have marked the course of modern macroeconomics: its emergence after the publication of Keynes’s General Theory, the heydays of Keynesian macroeconomics based on the IS-LM model, disequilibrium and non-Walrasian equilibrium modelling, the invention of the natural rate of unemployment notion, the new classical attack against Keynesian macroeconomics, the first wave of new Keynesian models, real business cycle modelling and, finally, the second wage of new Keynesian models, i.e. DSGE models. A main thrust of the paper is the contrast we draw between Keynesian macroeconomics and stochastic dynamic general equilibrium macroeconomics. We hope that our paper will be useful for teachers of macroeconomics wishing to complement their technical material with a historical addendum.Keynes, Lucas, IS-LM model, DSGE models

DISEQUILIBRIUM MACROECONOMICS: AN EPISODE IN THE TRANSFORMATION OF MODERN MACROECONOMICS

The paper investigates the rise and fall of the disequilibrium approach in macroeconomics between the mid 1960s and the late 1970s. During that period macroeconomists became attracted to the interpretation of unemployment phenomena based on the notion that markets are not in equilibrium. It was believed that such an approach could result in supply and demand functions distinct from those of conventional theory. However, by the late 1980s disequilibrium macroeconomics had largely disappeared from view, while approaches influenced by New Classical Macroeconomics and New Keynesian Economics became dominant. The present paper examines the contributions of the main authors - Patinkin, Clower, Leijonhufvud, Barro, Grossman, Solow, Stiglitz and Malinvaud - in order to offer a new pwerspective on the reasons for its sudden disappearance.

A Calculus for Orchestration of Web Services

Service-oriented computing, an emerging paradigm for distributed computing based on the use of services, is calling for the development of tools and techniques to build safe and trustworthy systems, and to analyse their behaviour. Therefore, many researchers have proposed to use process calculi, a cornerstone of current foundational research on specification and analysis of concurrent, reactive, and distributed systems. In this paper, we follow this approach and introduce CWS, a process calculus expressly designed for specifying and combining service-oriented applications, while modelling their dynamic behaviour. We show that CWS can model all the phases of the life cycle of service-oriented applications, such as publication, discovery, negotiation, orchestration, deployment, reconfiguration and execution. We illustrate the specification style that CWS supports by means of a large case study from the automotive domain and a number of more specific examples drawn from it

Report of the Intergovernmental Committee of Experts on Sustainable Development Financing

In order to achieve the Millennium Development Goals (MDGs), substantial additional external funding needs to be mobilized. Estimates differ, but a 'ballpark' figure is an annual increase of US$50 billion. This could be achieved by a doubling of official development assistance (ODA). Welcome steps have been made in that direction, but this takes time, and time is of the essence. For this reason alone, it is necessary to consider new sources.In this policy brief, we consider seven new sources:* Global environmental taxes (carbon-use tax)* Tax on currency flows (the 'Tobin tax')* Creation of new Special Drawing Rights (SDRs)* International Finance Facility (IFF)* Increased private donations for development* Global lottery and global premium bond * Increased remittances from emigrants

Macroeconomics - Which Way Now? Old versus New Styles

This paper contrasts the new style of doing macroeconomics, where the emphasis is on propositions rigorously derived from neoclassical micro foundations, with the old style associated with the work of Keynes in particular. The paper argues that the latter type of model, which is based on more realistic albeit informal behavioural micro foundations, is better suited to the concerns of policy makers. However, emphasis on the new style has led to an abandonment of research on adapting the old paradigms to new concerns, with a consequent loss for practical policy making especially with respect to macro stabilization. A perspective on how the new style can and cannot be helpful is provided.macroeconomic policy, neoclassical micro foundations, behavioural psychology