We consider the extension of non-monotonic preference logic with the distinction between controllable (or endogenous) and uncontrollable (or exogenous) variables, which can be used for example in agent decision making and deliberation. We assume that the agent is optimistic about its own controllables and pessimistic about its uncontrollables, and we study ways to merge these two distinct dimen...

Optimistic concurrency control relies on end-of-transaction validation rather than lock acquisition prior to data accesses. Optimistic concurrency control is popular and various systems employ it based on a conviction that it increases concurrency, performance, and scalability. In contrast, we have concluded that optimistic concurrency control permits more concurrency than pessimistic concurren...

Message logging protocols are an integral part of a technique for implementing processes that can recover from crash failures. All message logging protocols require that, when recovery is complete, there be no orphan processes, which are surviving processes whose states are inconsistent with the recovered state of a crashed process. We give a precise speciication of the consistency property \no...

Message-logging protocols are an integral part of a popular technique for implementing processes that can recover from crash failures. All message-logging protocols require that, when recovery is complete, there be no orphan processes , which are surviving processes whose states are inconsistent with the recovered state of a crashed process. We give a precise speci cation of the consistency pro...

There are two types of critical values for birandom variable: the optimistic and pessimistic values. In this paper, some theoretical aspects of optimistic and pessimistic values of birandom variable are investigated. Based on the results, some properties of birandom chance-constrained programming models can be further discussed.

This study examined the relationship between depressive symptoms and bias in the prediction of future life events. Responding to internet announcements, 153 participants varying widely in self-reported depression symptom severity estimated the probability of 40 events occurring over the succeeding 30 days. After the 30-day period, participants reported which events occurred. Optimistic/pessimis...

In this paper we consider real-time concurrency control for the nested transaction model. We analyze problems that have pure optimistic and pessimistic approaches. As the solution we propose a hybrid concurrency control algorithm which acts as an optimistic for transactions from different transaction trees and as pessimistic inside a single transaction tree.