Brian Cloteaux | National Institute of Standards and Technology (original) (raw)

Papers by Brian Cloteaux

DCFS, 2006

We investigate the relative computational power of three classes of pointer algorithms by compari... more We investigate the relative computational power of three classes of pointer algorithms by comparing time and space usage. These classes include two from Tarjan's original paper and another class which we introduce which is related to another long standing problem.

Winter Simulation Conference, Dec 13, 2009

Simulation of many dynamic real world systems such as the Internet and social networks requires d... more Simulation of many dynamic real world systems such as the Internet and social networks requires developing dynamic models for the underlying networks in these systems. Currently, there is a large body of work devoted towards determining the underlying mechanisms that create these networks, but the resulting models have not realistically captured many of the important structural characteristics when compared with real world examples. Towards creating more realistic dynamic models, we propose a method of structurally constructing models of an evolving network. We then conduct a series of computational experiments in modeling the evolution of the autonomous system (AS) topology of the Internet to test the effectiveness of our approach.

Winter Simulation Conference, Dec 11, 2011

Relationships between entities in many complex systems, such as the Internet and social networks,... more Relationships between entities in many complex systems, such as the Internet and social networks, have a natural hierarchical organization. Understanding these inherent hierarchies is essential for creating models of these systems. Thus, there is a recent body of research concerning the extraction of hierarchies from networks. We propose a new method for modeling hierarchies through extracting the affiliations of the network. From these affiliations, we construct a lattice of the relationships between nodes. A principal advantage of our approach is that any overlapping community structures of the nodes within the network have a natural representation within the lattice. We then show an example of our method using a real data set.

FCS, Jul 13, 2009

We study the complexity of accessing bits on a Pure Pointer Machine (PPM) or a pointer machine wi... more We study the complexity of accessing bits on a Pure Pointer Machine (PPM) or a pointer machine without arithmetic capabilities. In particular, we show that lower bounds in access time for information retrieval on a PPM arise from two independent factors: the complexity of information being stored and the amount of antisymmetry in the information. This result contrasts with earlier work by Ben-Amram and Galil that showed that for pointer machines with arithmetic capabilities look-up time depends only on the complexity of the information stored. We then demonstrate the use of these bounds to show optimal look-up times for comparing elements in partial and total orders on a PPM.

The economic and convenience benefits of interconnectivity drive the current explosive growth in ... more The economic and convenience benefits of interconnectivity drive the current explosive growth in networked systems. However, as recent catastrophic contagious failures in numerous large-scale networked infrastructures have demonstrated, interconnectivity is also inherently associated with various risks, including the risk of undesirable contagions. This paper reports on a work-in-progress on network formation subject to Susceptible-Infected-Susceptible (SIS) contagion risk mitigation. As opposed to existing research, we concentrate on network growth. Using a generalized form * Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States. of preferential attachment, we consider evolving networks where each incoming node to the network combines a preference for connecting to high degree nodes with an aversion for contagion risk. Our initial simulation results indicate that contagion risk aversion significantly alters the topology and contagion propagation for an emerging network. We also discuss the computational aspects of our simulation and our future plans to extend this model.

Journal of Research of the National Institute of Standards and Technology, Nov 19, 2019

For a degree sequence, we define the set of edges that appear in every labeled realization of tha... more For a degree sequence, we define the set of edges that appear in every labeled realization of that sequence as forced, while the edges that appear in none are define as forbidden. We examine the structure of graphs in which the degree sequences contain either forced or forbidden edges. The results include the determination of the structure of the forced or forbidden edge sets, the relationship between the sizes of forced and forbidden sets for a sequence, and the structural consequences to their realizations. This includes showing that the diameter of every realization of a degree sequence containing forced or forbidden edges is no greater than 3, and that these graphs are maximally edge-connected.

2022 IEEE 19th Annual Consumer Communications & Networking Conference (CCNC), Jan 8, 2022

A commonly used methodology to estimate the proximity of two individuals in an automatic exposure... more A commonly used methodology to estimate the proximity of two individuals in an automatic exposure notification system uses the signal strength of the Bluetooth signal from their mobile phones. However, there is an underlying error in Bluetooth-based proximity detection that can result in wrong exposure decisions. A wrong decision in the exposure determination leads to two types of errors: false negatives and false positives. A false negative occurs when an exposed individual is incorrectly identified as not exposed. Similarly, a false positive occurs when a non-exposed individual is mistakenly identified as exposed. Both errors have costly implications and can ultimately determine the effectiveness of Bluetooth-based automatic exposure notification in containment of pandemics such as COVID-19. In this paper, we present a platform that allows for the analysis of the system performance under various parameters. This platform enables us to gain a better understanding on how the underlying technology error propagates through the contact tracing system. Preliminary results show the considerable impact of the Bluetooth-based proximity estimation error on false exposure determination. Alternatively, using this platform, analysis can be performed to determine the acceptable accuracy level of a proximity detection mechanism in order to have a more effective contact tracing solution.

The reliability polynomial gives the probability that a graph remains connected given that each e... more The reliability polynomial gives the probability that a graph remains connected given that each edge in it can fail independently with an identical probability. While in general determining the coefficients of this polynomial is #P-complete, we give a randomized algorithm for approximating its coefficients. When compared to the known approximation method of Colbourn, Debroni and Myrvold, our method empirically shows a much faster rate of convergence.

arXiv (Cornell University), Sep 15, 2020

For an integer sequence (with even sum), the closer that the sequence is to being regular, the mo... more For an integer sequence (with even sum), the closer that the sequence is to being regular, the more likely that the sequence is graphic. But how regular must a sequence be before it must always be graphic? We show that for many sequences if all values are within n−2 4 of the mean degree value, then the sequence is graphic. We also see how this result extends to show when a maximum difference between sequence values implies that a sequence is graphic.

2023 IEEE International Conference on Communications Workshops (ICC Workshops)

arXiv (Cornell University), Dec 14, 2017

A variety of network modeling problems begin by generating a degree sequence drawn from a given p... more A variety of network modeling problems begin by generating a degree sequence drawn from a given probability distribution. If the randomly generated sequence is not graphic, we give a new approach for generating a graphic approximation of the sequence. This approximation scheme is fast, requiring only one pass through the sequence, and produces small probability distribution distances for large sequences.

Winter Simulation Conference, Dec 7, 2008

Recent research has shown that while many complex networks follow a power-law distribution for th... more Recent research has shown that while many complex networks follow a power-law distribution for their node degrees, it is not sufficient to model these networks based only on their degree distribution. In order to better distinguish between these networks, the metric s was introduced to measure how interconnected the hub nodes are in a network. We examine the effectiveness of creating network models based on this metric. Through a series of computational experiments, we compare how well a set of common structural network metrics are preserved between instances of the autonomous system Internet topology and a series of random models with identical degree sequences and similar s values. We demonstrate that creating models based on the s metric can produce moderate improvement in structural characteristics over strictly using degree distribution. Our results also indicate that some interesting relationships exist between the s metric and the various structural metrics.

Internet Mathematics, Mar 24, 2016

We examine the problem of creating random realizations of very large degree sequences. Although f... more We examine the problem of creating random realizations of very large degree sequences. Although fast in practice, the Markov chain Monte Carlo (MCMC) method for selecting a realization has limited usefulness for creating large graphs because of memory constraints. Instead, we focus on sequential importance sampling (SIS) schemes for random graph creation. A difficulty with SIS schemes is assuring that they terminate in a reasonable amount of time. We introduce a new sampling method by which we guarantee termination while achieving speed comparable to the MCMC method.

arXiv (Cornell University), 2018

We give a sufficient condition for a nonnegative integer list to be graphic based on its largest ... more We give a sufficient condition for a nonnegative integer list to be graphic based on its largest and smallest elements, length, and sum. This bound generalizes a result of Zverovich and Zverovich.

International Journal of Intelligent Systems, Sep 1, 1998

One of the most important parts of designing an expert system is elicitation of the expert's know... more One of the most important parts of designing an expert system is elicitation of the expert's knowledge. This knowledge usually consists of facts and rules. Eliciting these rules and facts is relatively easy, the more complicated task is assigning weights (numerical or interval-valued degrees of belief) to di erent statements from the knowledge base. Expert

Because of their importance to infrastructure, a number of studies have examined the structural p... more Because of their importance to infrastructure, a number of studies have examined the structural properties of power grids and have proposed random topological models of them. We examine the ability to create generalized models of power grid structure by comparing real data sets to see where inherent modeling limitations occur. We then propose a possible mechanism for why these networks differ in their structure, and the implications these differences have in creating power grid models. Finally, we introduce a new model for power grids with a radial-style architecture.

Proceedings of the 2010 Winter Simulation Conference, Dec 1, 2010

One way to help understand the structure of certain networks is to examine what common group memb... more One way to help understand the structure of certain networks is to examine what common group memberships the actors in the network share. Linking actors to their common affiliations gives an alternative type of network commonly called an affiliation network. Recently, there have been several studies examining the problem of modeling the dynamics of a network through the changes in the affiliations of its actors. We examine the closely related problem of modeling the affiliations for a given network. We especially focus on the case of trying to mine these affiliations when the original network is potentially missing links.