305,424 research outputs found
Optimal Investment with Stochastic Interest Rates and Ambiguity
This paper studies dynamic asset allocation with interest rate risk and
several sources of ambiguity. The market consists of a risk-free asset, a
zero-coupon bond (both determined by a Vasicek model), and a stock. There is
ambiguity about the risk premia, the volatilities, and the correlation. The
investor's preferences display both risk aversion and ambiguity aversion. The
optimal investment problem can be solved in closed-form under typical market
conditions. The solution shows that the investor does not hedge ambiguity but
only risk, while the ambiguity only affects the speculative motives of the
investor. An implementation of the optimal investment strategy shows the impact
of the different sources of ambiguity. Ambiguity aversion helps to tame the
highly leveraged portfolios neglecting ambiguity and leads to strategies that
are more in line with popular investment advice. The solution method for the
optimal investment problem is based on an extension of the martingale
optimality principle
Efficient Implementation with Interdependent Valuations and Maxmin Agents
We consider a single object allocation problem with multidimensional signals and interdependent valuations. When agents signals are statistically independent, Jehiel and Moldovanu show that efficient and Bayesian incentive compatible mechanisms generally do not exist. In this paper, we extend the standard model to accommodate maxmin agents and obtain necessary as well as sufficient conditions under which efficient allocations can be implemented. In particular, we derive a condition that quantifies the amount of ambiguity necessary for efficient implementation. We further show that under some natural assumptions on the preferences, this necessary amount of ambiguity becomes sufficient. Finally, we provide a definition of informational size such that given any nontrivial amount of ambiguity, efficient allocations can be implemented if agents are sufficiently informationally small
CHR Grammars
A grammar formalism based upon CHR is proposed analogously to the way
Definite Clause Grammars are defined and implemented on top of Prolog. These
grammars execute as robust bottom-up parsers with an inherent treatment of
ambiguity and a high flexibility to model various linguistic phenomena. The
formalism extends previous logic programming based grammars with a form of
context-sensitive rules and the possibility to include extra-grammatical
hypotheses in both head and body of grammar rules. Among the applications are
straightforward implementations of Assumption Grammars and abduction under
integrity constraints for language analysis. CHR grammars appear as a powerful
tool for specification and implementation of language processors and may be
proposed as a new standard for bottom-up grammars in logic programming.
To appear in Theory and Practice of Logic Programming (TPLP), 2005Comment: 36 pp. To appear in TPLP, 200
Identity ambiguity and the promises and practices of hybrid e-HRM project teams
The role of IS project team identity work in the enactment of day-to-day relationships with their internal clients is under-researched. We address this gap by examining the identity work undertaken by an electronic human resource management (e-HRM) 'hybrid' project team engaged in an enterprise-wide IS implementation for their multi-national organisation. Utilising social identity theory, we identify three distinctive, interrelated dimensions of project team identity work (project team management, team 'value propositions' (promises) and the team's 'knowledge practice'). We reveal how dissonance between two perspectives of e-HRM project identity work (clients' expected norms of project team's service and project team's expected norms of themselves) results in identity ambiguity. Our research contributions are to identity studies in the IS project management, HR and hybrid literatures and to managerial practice by challenging the assumption that hybrid experts are the panacea for problems associated with IS projects
Uniqueness of the Fock quantization of scalar fields in spatially flat cosmological spacetimes
We study the Fock quantization of scalar fields in (generically) time
dependent scenarios, focusing on the case in which the field propagation occurs
in --either a background or effective-- spacetime with spatial sections of flat
compact topology. The discussion finds important applications in cosmology,
like e.g. in the description of test Klein-Gordon fields and scalar
perturbations in Friedmann-Robertson-Walker spacetime in the observationally
favored flat case. Two types of ambiguities in the quantization are analyzed.
First, the infinite ambiguity existing in the choice of a Fock representation
for the canonical commutation relations, understandable as the freedom in the
choice of inequivalent vacua for a given field. Besides, in cosmological
situations, it is customary to scale the fields by time dependent functions,
which absorb part of the evolution arising from the spacetime, which is treated
classically. This leads to an additional ambiguity, this time in the choice of
a canonical pair of field variables. We show that both types of ambiguities are
removed by the requirements of (a) invariance of the vacuum under the
symmetries of the three-torus, and (b) unitary implementation of the dynamics
in the quantum theory. In this way, one arrives at a unique class of unitarily
equivalent Fock quantizations for the system. This result provides considerable
robustness to the quantum predictions and renders meaningful the confrontation
with observation.Comment: 15 pages, version accepted for publication in JCA
Policies that Succeed and Programs that Fail? Ambiguity, Conflict, and Crisis in Greek Higher Education
Why do some policies adopted by a wide margin fail to be implemented? Highlighting the role of policy entrepreneurial strategies within the Multiple Streams Approach (MSA), we examine the implementation of Greek higher education reform in 2011 to argue that when policies adversely affect the status quo, successful entrepreneurial strategies of issue-linkage and framing, side payments, and institutional rule manipulation are more likely to lead to implementation failure under conditions of crisis, centralized monopoly, and inconsistent political communication. The findings clarify MSA by specifying the conditions that increase the coupling strategies’ chances of success or failure and illuminate the role ambiguity and conflict play in policy reform and implementation
SECURITIES/ADMINISTRATIVE LAW—INTERNAL REPORTERS WHO BLOW THE WHISTLE: ARE THEY PROTECTED UNDER THE DODD-FRANK ACT’S ANTI-RETALIATION PROVISION?
In 2010, Congress enacted the Dodd-Frank Wall Street and Consumer Protection Act (the “Dodd-Frank Act”), which was a sweeping piece of legislation that required the implementation of new rules and regulations throughout the financial industry. Interpretative ambiguity exists within the Dodd-Frank Act’s whistleblower program, which provides a definition of who qualifies as a whistleblower, and an anti-retaliation provision, which is intended to protect whistleblowers from retaliation. The ambiguity arises because a whistleblower is defined as an individual who makes a report to the Securities and Exchange Commission (the “SEC”). However, the anti-retaliation provision describes three categories of protected whistleblowing activities, one of which can be construed as an exception to the whistleblower definition since it does not require disclosure to the SEC. The SEC sought to clarify this ambiguity by issuing a rule (the “SEC’s Rule”) explaining that retaliation protection under the Dodd-Frank Act extends to an individual who only reports possible securities law violations through his employer’s internal whistleblowing procedures
SECURITIES/ADMINISTRATIVE LAW—INTERNAL REPORTERS WHO BLOW THE WHISTLE: ARE THEY PROTECTED UNDER THE DODD-FRANK ACT’S ANTI-RETALIATION PROVISION?
In 2010, Congress enacted the Dodd-Frank Wall Street and Consumer Protection Act (the “Dodd-Frank Act”), which was a sweeping piece of legislation that required the implementation of new rules and regulations throughout the financial industry. Interpretative ambiguity exists within the Dodd-Frank Act’s whistleblower program, which provides a definition of who qualifies as a whistleblower, and an anti-retaliation provision, which is intended to protect whistleblowers from retaliation. The ambiguity arises because a whistleblower is defined as an individual who makes a report to the Securities and Exchange Commission (the “SEC”). However, the anti-retaliation provision describes three categories of protected whistleblowing activities, one of which can be construed as an exception to the whistleblower definition since it does not require disclosure to the SEC. The SEC sought to clarify this ambiguity by issuing a rule (the “SEC’s Rule”) explaining that retaliation protection under the Dodd-Frank Act extends to an individual who only reports possible securities law violations through his employer’s internal whistleblowing procedures
EU Facilitated Dialogue: Another exercise in constructive ambiguity. CEPS Commentary, 28 August 2015
Under the auspices of the EU, Belgrade and Pristina have signed new agreements on how to further normalise their relations. Yet these agreements, including on the creation of an Association/Community of Serb majority municipalities in Kosovo, are the continuation of an exercise in constructive ambiguity, argues Dusan Reljic in this CEPS Commentary. He makes the point that the proper implementation of these much heralded agreements will be something of a challenge
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