2,816 research outputs found
Uninsured Risks, Loan Contracts and the Declining Equity Premium
Using a two period model with moral hazard and uninsured risk, we argue that the decline in equity premium from its historically high level is due to a gradual elimination of barriers to universal banking. The loan contracts set up by financial intermediaries became more complete in nature with the advent of universal banking in the 90s following the Gramm-Leach-Billy Act. Hence, it is the nature of the loan contracts, not just the borrowing constraint and uninsured risks that is more fundamental in explaining the size of the equity premium.
Towards a Queueing-Based Framework for In-Network Function Computation
We seek to develop network algorithms for function computation in sensor
networks. Specifically, we want dynamic joint aggregation, routing, and
scheduling algorithms that have analytically provable performance benefits due
to in-network computation as compared to simple data forwarding. To this end,
we define a class of functions, the Fully-Multiplexible functions, which
includes several functions such as parity, MAX, and k th -order statistics. For
such functions we exactly characterize the maximum achievable refresh rate of
the network in terms of an underlying graph primitive, the min-mincut. In
acyclic wireline networks, we show that the maximum refresh rate is achievable
by a simple algorithm that is dynamic, distributed, and only dependent on local
information. In the case of wireless networks, we provide a MaxWeight-like
algorithm with dynamic flow splitting, which is shown to be throughput-optimal
Epidemic Thresholds with External Agents
We study the effect of external infection sources on phase transitions in
epidemic processes. In particular, we consider an epidemic spreading on a
network via the SIS/SIR dynamics, which in addition is aided by external agents
- sources unconstrained by the graph, but possessing a limited infection rate
or virulence. Such a model captures many existing models of externally aided
epidemics, and finds use in many settings - epidemiology, marketing and
advertising, network robustness, etc. We provide a detailed characterization of
the impact of external agents on epidemic thresholds. In particular, for the
SIS model, we show that any external infection strategy with constant virulence
either fails to significantly affect the lifetime of an epidemic, or at best,
sustains the epidemic for a lifetime which is polynomial in the number of
nodes. On the other hand, a random external-infection strategy, with rate
increasing linearly in the number of infected nodes, succeeds under some
conditions to sustain an exponential epidemic lifetime. We obtain similar sharp
thresholds for the SIR model, and discuss the relevance of our results in a
variety of settings.Comment: 12 pages, 2 figures (to appear in INFOCOM 2014
The Behavior of Epidemics under Bounded Susceptibility
We investigate the sensitivity of epidemic behavior to a bounded
susceptibility constraint -- susceptible nodes are infected by their neighbors
via the regular SI/SIS dynamics, but subject to a cap on the infection rate.
Such a constraint is motivated by modern social networks, wherein messages are
broadcast to all neighbors, but attention spans are limited. Bounded
susceptibility also arises in distributed computing applications with download
bandwidth constraints, and in human epidemics under quarantine policies.
Network epidemics have been extensively studied in literature; prior work
characterizes the graph structures required to ensure fast spreading under the
SI dynamics, and long lifetime under the SIS dynamics. In particular, these
conditions turn out to be meaningful for two classes of networks of practical
relevance -- dense, uniform (i.e., clique-like) graphs, and sparse, structured
(i.e., star-like) graphs. We show that bounded susceptibility has a surprising
impact on epidemic behavior in these graph families. For the SI dynamics,
bounded susceptibility has no effect on star-like networks, but dramatically
alters the spreading time in clique-like networks. In contrast, for the SIS
dynamics, clique-like networks are unaffected, but star-like networks exhibit a
sharp change in extinction times under bounded susceptibility.
Our findings are useful for the design of disease-resistant networks and
infrastructure networks. More generally, they show that results for existing
epidemic models are sensitive to modeling assumptions in non-intuitive ways,
and suggest caution in directly using these as guidelines for real systems
Relationship Banking, State Co-Ordination and Long-Term Debt: Reinterpreting the Big Push
We develop a lending game in which relationship-specific investments by firms benefit banks and vice versa. We show that even if all firms and banks prefer high-tech relationship loans under the first-best, asymmetric information and investment non-contractibility make them choose low-tech transaction loans. However, governments with intermediate risk ratings can use Groves subsidies for a concerted switch to long-term relationship loans. To avoid premature liquidation, they finance the scheme with long-term foreign debt. Thus, we try to explain the positive correlation between subsidies and long-term domestic and foreign debt, which was a salient feature of the East Asian development experience.Relationship Banking; Groves Subsidies; Intermediate Rating; Long-term Debt
Mass-Transport Models with Fragmentation and Aggregation
We present a review of nonequilibrium phase transitions in mass-transport
models with kinetic processes like fragmentation, diffusion, aggregation, etc.
These models have been used extensively to study a wide range of physical
problems. We provide a detailed discussion of the analytical and numerical
techniques used to study mass-transport phenomena.Comment: 29 pages, 4 figure
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