13,415 research outputs found
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
Distributed Kernel Regression: An Algorithm for Training Collaboratively
This paper addresses the problem of distributed learning under communication
constraints, motivated by distributed signal processing in wireless sensor
networks and data mining with distributed databases. After formalizing a
general model for distributed learning, an algorithm for collaboratively
training regularized kernel least-squares regression estimators is derived.
Noting that the algorithm can be viewed as an application of successive
orthogonal projection algorithms, its convergence properties are investigated
and the statistical behavior of the estimator is discussed in a simplified
theoretical setting.Comment: To be presented at the 2006 IEEE Information Theory Workshop, Punta
del Este, Uruguay, March 13-17, 200
Verifying the Interplay of Authorization Policies and Workflow in Service-Oriented Architectures (Full version)
A widespread design approach in distributed applications based on the
service-oriented paradigm, such as web-services, consists of clearly separating
the enforcement of authorization policies and the workflow of the applications,
so that the interplay between the policy level and the workflow level is
abstracted away. While such an approach is attractive because it is quite
simple and permits one to reason about crucial properties of the policies under
consideration, it does not provide the right level of abstraction to specify
and reason about the way the workflow may interfere with the policies, and vice
versa. For example, the creation of a certificate as a side effect of a
workflow operation may enable a policy rule to fire and grant access to a
certain resource; without executing the operation, the policy rule should
remain inactive. Similarly, policy queries may be used as guards for workflow
transitions.
In this paper, we present a two-level formal verification framework to
overcome these problems and formally reason about the interplay of
authorization policies and workflow in service-oriented architectures. This
allows us to define and investigate some verification problems for SO
applications and give sufficient conditions for their decidability.Comment: 16 pages, 4 figures, full version of paper at Symposium on Secure
Computing (SecureCom09
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An Ontological formalization of the planning task
In this paper we propose a generic task ontology, which formalizes the space of planning problems. Although planning is one of the oldest researched areas in Artificial Intelligence and attempts have been made in the past at developing task ontologies for planning, these formalizations suffer from serious limitations: they do not exhibit the required level of formalization and precision and they usually fail to include some of the key concepts required for specifying planning problems. In con-trast with earlier proposals, our task ontology formalizes the nature of the planning task independently of any planning paradigm, specific domains, or applications and provides a fine-grained, precise and comprehensive characterization of the space of planning problems. Finally, in addition to producing a formal specification we have also operationalized the ontology into a set of executable definitions, which provide a concrete reusable resource for knowledge acquisition and system development in planning applications
An Introduction to Mechanized Reasoning
Mechanized reasoning uses computers to verify proofs and to help discover new
theorems. Computer scientists have applied mechanized reasoning to economic
problems but -- to date -- this work has not yet been properly presented in
economics journals. We introduce mechanized reasoning to economists in three
ways. First, we introduce mechanized reasoning in general, describing both the
techniques and their successful applications. Second, we explain how mechanized
reasoning has been applied to economic problems, concentrating on the two
domains that have attracted the most attention: social choice theory and
auction theory. Finally, we present a detailed example of mechanized reasoning
in practice by means of a proof of Vickrey's familiar theorem on second-price
auctions
Towards a Conceptualization of Sociomaterial Entanglement
In knowledge representation, socio-technical systems can be modeled
as multiagent systems in which the local knowledge of each individual agent can
be seen as a context. In this paper we propose formal ontologies as a means to
describe the assumptions driving the construction of contexts as local theories and
to enable interoperability among them. In particular, we present two alternative
conceptualizations of the notion of sociomateriality (and entanglement), which
is central in the recent debates on socio-technical systems in the social sciences,
namely critical and agential realism.
We thus start by providing a model of entanglement according to the critical realist
view, representing it as a property of objects that are essentially dependent on
different modules of an already given ontology. We refine then our treatment by
proposing a taxonomy of sociomaterial entanglements that distinguishes between
ontological and epistemological entanglement. In the final section, we discuss the
second perspective, which is more challenging form the point of view of knowledge
representation, and we show that the very distinction of information into
modules can be at least in principle built out of the assumption of an entangled
reality
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