This paper is one of two companion papers which survey price elasticities of transport demand. In addition to reviewing empirical elasticity estimates for both freight and passenger demand, this paper also deals with theoretical and empirical issues in estimating transport demand elasticities. The second survey, by Dr. Philip Goodwin, is primarily concerned with empirical estimates of demand elasticities of public traansit system and automobile usage. The origins of motivations of these two papers were different. As was the coverage and sources used. The two papers complemented each other and are therefore published together with a pooled bibliography.

Concepts of price elasticities of transport demand and recent empirical estimates: an interpretative survey. in: urban transport

We study the network dismantling problem, which consists of determining a minimal set of vertices in which removal leaves the network broken into connected components of subextensive size. For a large class of random graphs, this problem is tightly connected to the decycling problem (the removal of vertices, leaving the graph acyclic). Exploiting this connection and recent works on epidemic spreading, we present precise predictions for the minimal size of a dismantling set in a large random graph with a prescribed (light-tailed) degree distribution. Building on the statistical mechanics perspective, we propose a three-stage Min-Sum algorithm for efficiently dismantling networks, including heavy-tailed ones for which the dismantling and decycling problems are not equivalent. We also provide additional insights into the dismantling problem, concluding that it is an intrinsically collective problem and that optimal dismantling sets cannot be viewed as a collection of individually well-performing nodes.

https://www.pnas.org/content/pnas/113/44/12368.full.pdf

Network dismantling

Preface. Economic Topics. Computable general equilibrium modelling for policy analysis and forecasting (P.B. Dixon, B.R. Parmenter). Computation of equilibria in finite games (R.D. McKelvey, A. McLennan). Computational methods for macroeconomic models (R.C. Fair). Mechanics of forming and estimating dynamic linear economies (E.W. Andersen et al.). Nonlinear pricing and mechanism design (R. Wilson). Sectoral economics (D.A. Kendrick). Computer Science Parallel computation (A. Nagurney). Artificial intelligence in economics and finance: A state of the art - 1994 (L.F. Pau, P.-Y. Tan). Neural networks for encoding and adapting in dynamic economies (I.-K. Cho, T.J. Sargent). Modelling languages in computational economics: GAMS (S.A. Zenios). Numerical Methods. Mathematica for economists (H. Varian). Approximation, perturbation, and projection methods in economic analysis (K.L. Judd). Numerical methods for linear-quadratic models (H.M. Amman). Numerical dynamic programming in economics (J. Rust). Monte Carlo simulation and numerical integration (J. Geweke).

/pdf/handbook-of-computational-economics-531sv06e9a.pdf

Handbook of Computational Economics

In r-neighbour bootstrap percolation on a graph G, a (typically random) set A of initially 'infected' vertices spreads by infecting (at each time step) vertices with at least r already-infected neighbours. This process may be viewed as a monotone version of the Glauber dynamics of the Ising model, and has been extensively studied on the d-dimensional grid $[n]^d$. The elements of the set A are usually chosen independently, with some density p, and the main question is to determine $p_c([n]^d,r)$, the density at which percolation (infection of the entire vertex set) becomes likely. In this paper we prove, for every pair $d ge r ge 2$, that there is a constant L(d,r) such that $p_c([n]^d,r) = [(L(d,r) + o(1)) / log_(r-1) (n)]^{d-r+1}$ as $n o infty$, where $log_r$ denotes an r-times iterated logarithm. We thus prove the existence of a sharp threshold for percolation in any (fixed) number of dimensions. Moreover, we determine L(d,r) for every pair (d,r).

/pdf/the-sharp-threshold-for-bootstrap-percolation-in-all-20zlugcfe8.pdf

The sharp threshold for bootstrap percolation in all dimensions

A Roman dominating function of a graph $G$ is a labeling $f\colon\,V(G)\to\{0,1,2\}$ such that every vertex with label 0 has a neighbor with label 2. The Roman domination number $\gamma_R(G)$ of $G$ is the minimum of $\sum_{v\in V(G)}f(v)$ over such functions. Let $G$ be a connected $n$-vertex graph. We prove that $\gamma_R(G)\leq4n/5$, and we characterize the graphs achieving equality. We obtain sharp upper and lower bounds for $\gamma_R(G)+\gamma_R(\overline{G})$ and $\gamma_R(G)\gamma_R(\overline{G})$, improving known results for domination number. We prove that $\gamma_R(G)\leq8n/11$ when $\delta(G)\geq2$ and $n\geq9$, and this is sharp.

/pdf/extremal-problems-for-roman-domination-3jfuzvibqh.pdf

Extremal Problems for Roman Domination

Roman domination in graphs

Irreversible k-threshold processes: Graph-theoretical threshold models of the spread of disease and of opinion

This paper discusses how to protect commercial aircraft and airlines from man-portable air defense systems (MANPADS). MANPADS are shoulder fired missiles that are available worldwide, are relatively inexpensive, and offer terrorists the option of bringing down aircraft at any airport. The following topics are covered in the paper: (1) the severity and nature of the threat that terrorist groups might have MANPADS and the possible economic impacts of missile attacks on commercial aircraft in the United States; (2) how the MANPADS threat fits into the broader context of the war on terrorism; (3) tactical and operational aspects of the threat, including options for limiting the access that terrorists have to potential targets and weapons, and potential operating areas in and around major airports; (4) the limitations and characteristics of technical alternatives for aborting missiles after they have been launched; (5) the possible cost of the development, installation and maintenance of selected countermeasure systems and who should pay for them; and (6) recommendations of where to go from here.

/pdf/protecting-commercial-aviation-against-the-shoulder-fired-owq0ejff4z.pdf

Protecting Commercial Aviation Against the Shoulder-Fired Missile Threat

Space is now a congested, contested, and competitive environment. Space systems must become more resilient to potential adversary actions and system failures, but changes to space systems are costly. To reduce costs, the Air Force asked RAND to identify non-materiel means — doctrine, organization, training, leadership and education, personnel, facilities, and policy — to enhance space resilience over the near and far terms.

/pdf/enhancing-space-resilience-through-non-materiel-means-4q116wpiw2.pdf

Enhancing Space Resilience Through Non-Materiel Means

: We begin by giving some background on the problem we are addressing, including a summary of our prior work in this area and what we recommended to the government in March 2002. We then describe our findings from this work, connecting it to the prior work and pointing toward a new set of recommendations. We lead the reader through the steps of the analysis, starting with how we calculated the various baggage-scanning delays, how those delays were translated into passengers choosing to arrive at the airports earlier than otherwise necessary, and how that behavior is ultimately reflected in additional cost to the nation's economy. This briefing is relatively long because a number of important sensitivities need to be addressed.

/pdf/how-much-is-enough-sizing-the-deployment-of-baggage-31tdgs3xrw.pdf

Paul Dreyer

Papers

Roman domination in graphs

Irreversible k-threshold processes: Graph-theoretical threshold models of the spread of disease and of opinion

Protecting Commercial Aviation Against the Shoulder-Fired Missile Threat

Enhancing Space Resilience Through Non-Materiel Means

How Much Is Enough?: Sizing the Deployment of Baggage Screening Equipment by Considering the Economic Cost of Passenger Delays