Generalized Spot-Checking for Reliable Volunteer Computing

Abstract

SUMMARYWhile volunteer computing (VC) systems reach the most powerful computing platforms, they still have the problem of guaranteeing computational correctness, due to the inherent unreliability of volunteer participants. Spot-checking technique, which checks each participant by allocating spotter jobs, is a promising approach to the validation of computation results. The current spot-checking is based on the implicit assumption that participants never distinguish spotter jobs from normal ones; however generating such spotter jobs is still an open problem. Hence, in the real VC environment where the implicit assumption does not always hold, spot-checking-based methods such as well-known credibility-based voting become almost impossible to guarantee the computational correctness. In this paper, we generalize spot-checking by introducing the idea of imperfect checking. This generalization allows to guarantee the computational correctness under the situation that spot-checking is not fully-reliable and participants may distinguish spotter jobs. Moreover, we develop a generalized formula of the credibility, which enables credibility-based voting to utilize check-by-voting technique. Simulation results show that check-byvoting improves the performance of credibility-based voting, while guaranteeing the same level of computational correctness.

Dynamic Job Scheduling Method Based on Expected Probability of Completion of Voting in Volunteer Computing

“…Each credibility is defined as follows [19]. The credibility of a worker w i , denoted by C W (w i ), is given by Eqs.…”

“…Following the common assumption [19], [21], [22], workers are assumed to return their result in one time step. The length of a time step depends on the VC applications (i.e.…”

Performance Evaluation of Check-By-Voting for Colluding Attack in Volunteer Computing Systems

“…Check-by-voting [8,9] is the upgraded version of M-first voting, which introduces the idea of a weighted voting. In check-by-voting, the master gives a credibility value to each worker which represents how the worker is reliable.…”

“…For these problems, the authors have developed the following technique and formula [8]. As a feature, the credibility in the developed formula is given as a conditional probability so that the expected value of the error rate e is less than an arbitrary value e acc for any cases of s and f. This condition e B e acc is called reliability condition.…”

“…Because s and f are unknown to the master, the credibility should be given by the upper bound for s and f. The parameter f max is the assumed ratio of saboteurs and given by the master so that the condition f B f max is satisfied. Using C W (w), the credibility of other VC elements such as result group and job are also defined (see [8] for details).…”