The optimistic consistency scheme has been established with respect to data consistency and availability in distributed systems. Wireless networks are becoming popular in data communication and suitable for data sharing among users using multicast capability, but have hidden node problems. This paper proposes a simple data coherency protocol for mobile devices that is less data traffic in data ...

To improve the performance of geographically distributed cosimulation, we propose a concept called hierarchically grouped message. The concept improves cosimulation performance, preserving the cosimulation accuracy, by hierarchically grouping messages transferred between simulators in a short period of simulated time into a single physical message, thereby reducing the number of physical messag...

Abstract Data Envelopment Analysis (DEA) can be regarded as a useful management tool to the assessment evaluation of decision making units (DMUs) using multiple inputs to produce multiple outputs. In some cases, to evaluate the efficiency having imprecise inputs and outputs such as fuzzy or interval data the efficiency of DMUs won’t be exact as well. Most researches have been conducted were bas...

In this study, both optimistic and pessimistic approaches of data envelopment analysis are applied to propose an equitable ranking method in fuzzy environments. To this end, we suppose that the sum of efficiency scores of all decision making units (DMUs) equals to unity. Using the worst-best and best-worst approaches, the minimum and maximum possible efficiency scores of each DMU are estimated ...

We study the stability of voluntary cooperation in response to varying group growth rates. Using a laboratory public-good game, we construct a situation where increasing group size yields potential efficiency gains, but only with sustained cooperation. We then study the effect of exogenously varying growth rates on cooperation. Slow growth yields higher cooperation rates and welfare than fast g...

Security services become crucial to many applications such as e-commerce payment protocols, electronic contract signing, and certified e-mail delivery, with the phenomenal growth of the Internet and open networks. For these applications fair exchange must be assured. A fair protocol allows two parties to exchange digital signatures over the Internet in a fair way, so that either each party gets...

We recently applied a multistage reweighting scheme to demonstrate the sampling of equilibrium configurational distributions of peptides from nonequilibrium, simulated annealing trajectories [E. Lyman and D. M. Zuckerman, J. Chem. Phys. 127, 065101 (2007)]. Here we demonstrate that a statistical variance reduction technique, resampling, improves the efficiency of the protocol by about a factor ...

The replica exchange approach, also called parallel tempering, is gaining popularity for biomolecular simulation. We ask whether the approach is likely to be efficient compared to standard simulation methods for fixed-temperature equilibrium sampling. To examine the issue, we make a number of straightforward observations on how "fast" high-temperature molecular simulations can be expected to ru...