2,889 research outputs found
A Flexible Network Approach to Privacy of Blockchain Transactions
For preserving privacy, blockchains can be equipped with dedicated mechanisms
to anonymize participants. However, these mechanism often take only the
abstraction layer of blockchains into account whereas observations of the
underlying network traffic can reveal the originator of a transaction request.
Previous solutions either provide topological privacy that can be broken by
attackers controlling a large number of nodes, or offer strong and
cryptographic privacy but are inefficient up to practical unusability. Further,
there is no flexible way to trade privacy against efficiency to adjust to
practical needs. We propose a novel approach that combines existing mechanisms
to have quantifiable and adjustable cryptographic privacy which is further
improved by augmented statistical measures that prevent frequent attacks with
lower resources. This approach achieves flexibility for privacy and efficency
requirements of different blockchain use cases.Comment: 6 pages, 2018 IEEE 38th International Conference on Distributed
Computing Systems (ICDCS
Non-blocking Patricia Tries with Replace Operations
This paper presents a non-blocking Patricia trie implementation for an
asynchronous shared-memory system using Compare&Swap. The trie implements a
linearizable set and supports three update operations: insert adds an element,
delete removes an element and replace replaces one element by another. The
replace operation is interesting because it changes two different locations of
tree atomically. If all update operations modify different parts of the trie,
they run completely concurrently. The implementation also supports a wait-free
find operation, which only reads shared memory and never changes the data
structure. Empirically, we compare our algorithms to some existing set
implementations.Comment: To appear in the 33rd IEEE International Conference on Distributed
Computing Systems (ICDCS 2013
On Consistency of Graph-based Semi-supervised Learning
Graph-based semi-supervised learning is one of the most popular methods in
machine learning. Some of its theoretical properties such as bounds for the
generalization error and the convergence of the graph Laplacian regularizer
have been studied in computer science and statistics literatures. However, a
fundamental statistical property, the consistency of the estimator from this
method has not been proved. In this article, we study the consistency problem
under a non-parametric framework. We prove the consistency of graph-based
learning in the case that the estimated scores are enforced to be equal to the
observed responses for the labeled data. The sample sizes of both labeled and
unlabeled data are allowed to grow in this result. When the estimated scores
are not required to be equal to the observed responses, a tuning parameter is
used to balance the loss function and the graph Laplacian regularizer. We give
a counterexample demonstrating that the estimator for this case can be
inconsistent. The theoretical findings are supported by numerical studies.Comment: This paper is accepted by 2019 IEEE 39th International Conference on
Distributed Computing Systems (ICDCS
On the Minimal Knowledge Required for Solving Stellar Consensus
Byzantine Consensus is fundamental for building consistent and fault-tolerant
distributed systems. In traditional quorum-based consensus protocols, quorums
are defined using globally known assumptions shared among all participants.
Motivated by decentralized applications on open networks, the Stellar
blockchain relaxes these global assumptions by allowing each participant to
define its quorums using local information. A similar model called Consensus
with Unknown Participants (CUP) studies the minimal knowledge required to solve
consensus in ad-hoc networks where each participant knows only a subset of
other participants of the system. We prove that Stellar cannot solve consensus
using the initial knowledge provided to participants in the CUP model, even
though CUP can. We propose an oracle called sink detector that augments this
knowledge, enabling Stellar participants to solve consensus.Comment: Preprint of a paper to appear at the 43rd IEEE International
Conference on Distributed Computing Systems (ICDCS 2023
Joint Optimization of Energy Consumption and Completion Time in Federated Learning
Federated Learning (FL) is an intriguing distributed machine learning
approach due to its privacy-preserving characteristics. To balance the
trade-off between energy and execution latency, and thus accommodate different
demands and application scenarios, we formulate an optimization problem to
minimize a weighted sum of total energy consumption and completion time through
two weight parameters. The optimization variables include bandwidth,
transmission power and CPU frequency of each device in the FL system, where all
devices are linked to a base station and train a global model collaboratively.
Through decomposing the non-convex optimization problem into two subproblems,
we devise a resource allocation algorithm to determine the bandwidth
allocation, transmission power, and CPU frequency for each participating
device. We further present the convergence analysis and computational
complexity of the proposed algorithm. Numerical results show that our proposed
algorithm not only has better performance at different weight parameters (i.e.,
different demands) but also outperforms the state of the art.Comment: This paper appears in the Proceedings of IEEE International
Conference on Distributed Computing Systems (ICDCS) 2022. Please feel free to
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