In this paper, we study the performance of an access concurrency control algorithm for transaction time relations. This algorithm is based on the optimistic approach and detects conflicts as soon as possible. By using EOT marker technique, it has the merit to reduce to the maximum the period during which resources are locked in the validation phase [3]. We have, in previous works, made a formal...

Much of the literature on message logging and checkpointing in the past decade has been based on a so-called optimistic approach 1] that places more emphasis on failure-free overhead than recovery ee-ciency. Our experience has shown that most telecommunications systems use a pessimistic approach because the main purpose of using message logging and checkpointing is to achieve fast and localized...

data envelopment analysis (dea) is a method to measure relative efficiency of a set of decision-making units (dmus) which uses multiple inputs and produces multiple outputs. in the conventional dea, crisp inputs and outputs are fundamentally necessary. but the observed values of inputs and outputs in real-world problems are sometimes imprecise. thus, performance measurement often needs to be do...

OBJECTIVES Previous projections of mortality from mesothelioma among French men have used the age-generation method, based on the Poisson regression model. In this study an alternative method to model mortality from mesothelioma was used to predict its future trend: this method was based on the risk function that links this mortality to past exposure to asbestos, combined with population exposu...

Optimistic replication is a fundamental technique for supporting collaborative work practices in mobile environments. However, eventual consistency, in contrast to immediate strong consistency in pessimistic replication, is much harder to evaluate. This paper analyzes different metrics for measuring the effectiveness of eventually consistent systems. Using results from a simulated environment o...

Optimistic methods of concurrency control are gaining popularity. This is especially true with the resurgence of mobile and distributed databases during the last decade, which inherently rely on optimistic techniques to improve availability and performance of the distributed database systems. A key problem with optimistic techniques is that they do not perform well in highly conflict prone envi...

Climate negotiation outcomes are difficult to evaluate objectively because there are no clear reference scenarios. Subjective assessments from those directly involved in the negotiations are particularly important, as this may influence strategy and future negotiation participation. Here we analyze the perceived success of the climate negotiations in a sample of more than 600 experts involved i...

Humans hold unrealistically optimistic predictions of what their future holds. These predictions are generated and maintained as people update their beliefs more readily when receiving information that calls for adjustment in an optimistic direction relative to information that calls for adjustment in a pessimistic direction. Thus far this update bias has been shown when people make estimations...