19 research outputs found
Delay Impact on Stubborn Mining Attack Severity in Imperfect Bitcoin Network
Stubborn mining attack greatly downgrades Bitcoin throughput and also
benefits malicious miners (attackers). This paper aims to quantify the impact
of block receiving delay on stubborn mining attack severity in imperfect
Bitcoin networks. We develop an analytic model and derive formulas of both
relative revenue and system throughput, which are applied to study attack
severity. Experiment results validate our analysis method and show that
imperfect networks favor attackers. The quantitative analysis offers useful
insight into stubborn mining attack and then helps the development of
countermeasures.Comment: arXiv admin note: text overlap with arXiv:2302.0021
CRS-FL: Conditional Random Sampling for Communication-Efficient and Privacy-Preserving Federated Learning
Federated Learning (FL), a privacy-oriented distributed ML paradigm, is being
gaining great interest in Internet of Things because of its capability to
protect participants data privacy. Studies have been conducted to address
challenges existing in standard FL, including communication efficiency and
privacy-preserving. But they cannot achieve the goal of making a tradeoff
between communication efficiency and model accuracy while guaranteeing privacy.
This paper proposes a Conditional Random Sampling (CRS) method and implements
it into the standard FL settings (CRS-FL) to tackle the above-mentioned
challenges. CRS explores a stochastic coefficient based on Poisson sampling to
achieve a higher probability of obtaining zero-gradient unbiasedly, and then
decreases the communication overhead effectively without model accuracy
degradation. Moreover, we dig out the relaxation Local Differential Privacy
(LDP) guarantee conditions of CRS theoretically. Extensive experiment results
indicate that (1) in communication efficiency, CRS-FL performs better than the
existing methods in metric accuracy per transmission byte without model
accuracy reduction in more than 7% sampling ratio (# sampling size / # model
size); (2) in privacy-preserving, CRS-FL achieves no accuracy reduction
compared with LDP baselines while holding the efficiency, even exceeding them
in model accuracy under more sampling ratio conditions
PA-iMFL: Communication-Efficient Privacy Amplification Method against Data Reconstruction Attack in Improved Multi-Layer Federated Learning
Recently, big data has seen explosive growth in the Internet of Things (IoT).
Multi-layer FL (MFL) based on cloud-edge-end architecture can promote model
training efficiency and model accuracy while preserving IoT data privacy. This
paper considers an improved MFL, where edge layer devices own private data and
can join the training process. iMFL can improve edge resource utilization and
also alleviate the strict requirement of end devices, but suffers from the
issues of Data Reconstruction Attack (DRA) and unacceptable communication
overhead. This paper aims to address these issues with iMFL. We propose a
Privacy Amplification scheme on iMFL (PA-iMFL). Differing from standard MFL, we
design privacy operations in end and edge devices after local training,
including three sequential components, local differential privacy with Laplace
mechanism, privacy amplification subsample, and gradient sign reset.
Benefitting from privacy operations, PA-iMFL reduces communication overhead and
achieves privacy-preserving. Extensive results demonstrate that against
State-Of-The-Art (SOTA) DRAs, PA-iMFL can effectively mitigate private data
leakage and reach the same level of protection capability as the SOTA defense
model. Moreover, due to adopting privacy operations in edge devices, PA-iMFL
promotes up to 2.8 times communication efficiency than the SOTA compression
method without compromising model accuracy.Comment: 12 pages, 11 figure
Improving Sensing Accuracy in Cognitive PANs through Modulation of Sensing Probability
Cognitive radio technology necessitates accurate and timely sensing of primary users' activity on the chosen set of channels. The simplest selection procedure is a simple random choice of channels to be sensed, but the impact of sensing errors with respect to primary user activity or inactivity differs considerably. In order to improve sensing accuracy and increase the likelihood of finding channels which are free from primary user activity, the selection procedure is modified by assigning different sensing probabilities to active and inactive channels. The paper presents a probabilistic analysis of this policy and investigates the range of values in which the modulation of sensing probability is capable of maintaining an accurate view of the status of the working channel set. We also present a modification of the probability modulation algorithm that allows for even greater reduction of sensing error in a limited range of the duty cycle of primary users' activity. Finally, we give some guidelines as to the optimum application ranges for the original and modified algorithm, respectively
Improving sensing accuracy in cognitive PANs through modulation of sensing probability 1
Abstract. Cognitive radio technology necessitates accurate and timely sensing of primary users' activity on the chosen set of channels. The simplest selection procedure is a simple random choice of channels to be sensed, but the impact of sensing errors with respect to primary user activity or inactivity differs considerably. In order to improve sensing accuracy and increase the likelihood of finding channels which are free from primary user activity, the selection procedure is modified by assigning different sensing probabilities to active and inactive channels. The paper presents a probabilistic analysis of this policy and investigates the range of values in which the modulation of sensing probability is capable of maintaining an accurate view of the status of the working channel set. We also present a modification of the probability modulation algorithm that allows for even greater reduction of sensing error in a limited range of the duty cycle of primary users' activity. Finally, we give some guidelines as to the optimum application ranges for the original and modified algorithm, respectively
Priority-Based Machine-To-Machine Overlay Network over LTE for a Smart City
Long-Term Evolution (LTE) and its improvement, Long-Term Evolution-Advanced (LTE-A), are attractive choices for Machine-to-Machine (M2M) communication due to their ubiquitous coverage and high bandwidth. However, the focus of LTE design was high performance connection-based communications between human-operated devices (also known as human-to-human, or H2H traffic), which was initially established over the Physical Random Access Channel (PRACH). On the other hand, M2M traffic is mostly based on contention-based transmission of short messages and does not need connection establishment. As a result, M2M traffic transmitted over LTE PRACH has to use the inefficient four-way handshake and compete for resources with H2H traffic. When a large number of M2M devices attempts to access the PRACH, an outage condition may occur; furthermore, traffic prioritization is regulated only through age-based power ramping, which drives the network even faster towards the outage condition. In this article, we describe an overlay network that allows a massive number of M2M devices to coexist with H2H traffic and access the network without going through the full LTE handshake. The overlay network is patterned after IEEE 802.15.6 to support multiple priority classes of M2M traffic. We analyse the performance of the joint M2M and H2H system and investigate the trade-offs needed to keep satisfactory performance and reliability for M2M traffic in the presence of H2H traffic of known intensity. Our results confirm the validity of this approach for applications in crowd sensing, monitoring and others utilized in smart city development
Modeling a beacon enabled 802.15.4 cluster with bidirectional traffic
Abstract. We analyze the performance of an IEEE 802.15.4 compliant network cluster operating in the beacon enabled mode with both downlink and uplink traffic. We investigate the non-saturation regime and outline the conditions under which the network abruptly goes to saturation. The operation of the WPAN is modeled through discrete time Markov chains and the theory of M/G/1 queues. The model considers acknowledged transmissions and includes the impact of different network and traffic parameters such as the packet arrival rate, packet size, inactive period between the beacons, and the number of stations. We analyze the stability of the network queues and show that the stability of the downlink queue at the coordinator is the most critical for network operation
Analyzing the Cost and Benefit of Pair Programming Revisited
Pair programming has received a lot of attention from both industry and academia, but most paper focus on its technical aspects, while its business value has received much less attention.Ā In this paper, we focus on the business aspects of pair programming, by using a number of software development related met rics, such as pair speed advantage, module breakdown structureĀ of the software and project value discount rate, and augmenting them by taking into account the cost of change after the initial product release and inherent non-linearity of the discount rate curves. The proposed model allows for a more realistic estimation of the final project value, and the results of System Dynamics simulations demonstrate some useful insights for software development management