Chryssis Georgiou

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In this paper, we study the complexity of gossip in an asynchronous, message-passing fault-prone distributed system. In short, we show that an adaptive adversary can significantly hamper the spreading of a rumor, while an oblivious adversary cannot. This latter fact implies that there exist message-efficient asynchronous (randomized) consensus protocols, in(More)
The ability to cooperate on common tasks in a distributed setting is key to solving a broad range of computation problems ranging from distributed search such as SETI to distributed simulation and multi-agent collaboration. Do-All, an abstraction of such cooperative activity, is the problem of performing N tasks in a distributed system of P failure-prone(More)
Distributed Computing Theory continues to be one of the most active research fields in Theoretical Computer Science today. Besides its foundational topics (such as consensus and synchronization), it is currently being enriched with many new topics inspired from modern technological advances (e.g., the Internet). In this note, we present eight open problems(More)
In this work we consider a distributed system formed by a master processor and a collection of n processors (workers) that can execute tasks; worker processors are untrusted and might act maliciously. The master assigns tasks to workers to be executed. Each task returns a binary value, and we want the master to accept only correct values with high(More)
This paper presents an efficient deterministic gossip algorithm for p synchronous, crash-prone, message-passing processors. The algorithm has time complexity T = O(log2p) and message complexity M = O(p1+ ), for any > 0. This substantially improves the message complexity of the previous best algorithm that has M = O(p1.77), while maintaining the same time(More)
This paper investigates time-efficient implementations of atomic read-write registers in message-passing systems where the number of readers can be unbounded. In particular we study the case of a single writer, multiple readers, and <i>S</i> servers, such that the writer, any subset of the readers, and up to <i>t</i> servers may crash. A recent result of(More)
Shareable data services providing consistency guarantees, such as atomicity (linearizability), make building distributed systems easier. However, combining linearizability with efficiency in practical algorithms is difficult. A reconfigurable linearizable data service, called Rambo, was developed by Lynch and Shvartsman. This service guarantees consistency(More)
This work considers the problem of performing a set of N tasks on a set of P message-passing processors P N . The processors use a group communication service (GCS) to coordinate their activity in the setting with dynamic network changes. We investigate work-efficient and message-efficient algorithms for fragmentations and merges of processor groups. We(More)
We study the problem of selfish routing in the presence of incomplete network information. Our model consists of a number of users who wish to route their traffic on a network of m parallel links with the objective of minimizing their latency. However, in doing so, they face the challenge of lack of precise information on the capacity of the network links.(More)