164,783 research outputs found

    A multi-objective interpretation of optimal transport

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    Physiology-Aware Rural Ambulance Routing

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    In emergency patient transport from rural medical facility to center tertiary hospital, real-time monitoring of the patient in the ambulance by a physician expert at the tertiary center is crucial. While telemetry healthcare services using mobile networks may enable remote real-time monitoring of transported patients, physiologic measures and tracking are at least as important and requires the existence of high-fidelity communication coverage. However, the wireless networks along the roads especially in rural areas can range from 4G to low-speed 2G, some parts with communication breakage. From a patient care perspective, transport during critical illness can make route selection patient state dependent. Prompt decisions with the relative advantage of a longer more secure bandwidth route versus a shorter, more rapid transport route but with less secure bandwidth must be made. The trade-off between route selection and the quality of wireless communication is an important optimization problem which unfortunately has remained unaddressed by prior work. In this paper, we propose a novel physiology-aware route scheduling approach for emergency ambulance transport of rural patients with acute, high risk diseases in need of continuous remote monitoring. We mathematically model the problem into an NP-hard graph theory problem, and approximate a solution based on a trade-off between communication coverage and shortest path. We profile communication along two major routes in a large rural hospital settings in Illinois, and use the traces to manifest the concept. Further, we design our algorithms and run preliminary experiments for scalability analysis. We believe that our scheduling techniques can become a compelling aid that enables an always-connected remote monitoring system in emergency patient transfer scenarios aimed to prevent morbidity and mortality with early diagnosis treatment.Comment: 6 pages, The Fifth IEEE International Conference on Healthcare Informatics (ICHI 2017), Park City, Utah, 201

    Strong Duality for a Multiple-Good Monopolist

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    We characterize optimal mechanisms for the multiple-good monopoly problem and provide a framework to find them. We show that a mechanism is optimal if and only if a measure μ\mu derived from the buyer's type distribution satisfies certain stochastic dominance conditions. This measure expresses the marginal change in the seller's revenue under marginal changes in the rent paid to subsets of buyer types. As a corollary, we characterize the optimality of grand-bundling mechanisms, strengthening several results in the literature, where only sufficient optimality conditions have been derived. As an application, we show that the optimal mechanism for nn independent uniform items each supported on [c,c+1][c,c+1] is a grand-bundling mechanism, as long as cc is sufficiently large, extending Pavlov's result for 22 items [Pavlov'11]. At the same time, our characterization also implies that, for all cc and for all sufficiently large nn, the optimal mechanism for nn independent uniform items supported on [c,c+1][c,c+1] is not a grand bundling mechanism

    A numerical algorithm for L2L_2 semi-discrete optimal transport in 3D

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    This paper introduces a numerical algorithm to compute the L2L_2 optimal transport map between two measures μ\mu and ν\nu, where μ\mu derives from a density ρ\rho defined as a piecewise linear function (supported by a tetrahedral mesh), and where ν\nu is a sum of Dirac masses. I first give an elementary presentation of some known results on optimal transport and then observe a relation with another problem (optimal sampling). This relation gives simple arguments to study the objective functions that characterize both problems. I then propose a practical algorithm to compute the optimal transport map between a piecewise linear density and a sum of Dirac masses in 3D. In this semi-discrete setting, Aurenhammer et.al [\emph{8th Symposium on Computational Geometry conf. proc.}, ACM (1992)] showed that the optimal transport map is determined by the weights of a power diagram. The optimal weights are computed by minimizing a convex objective function with a quasi-Newton method. To evaluate the value and gradient of this objective function, I propose an efficient and robust algorithm, that computes at each iteration the intersection between a power diagram and the tetrahedral mesh that defines the measure μ\mu. The numerical algorithm is experimented and evaluated on several datasets, with up to hundred thousands tetrahedra and one million Dirac masses.Comment: 23 pages, 14 figure

    An economic theory of church strictness

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    This paper makes several contributions to the growing literature on the economics of religion. First, we explicitly introduce spatial- location models into the economics of religion. Second, we offer a new explanation for the observed tendency of state (monopoly) churches to locate toward the "low-tension" end of the "strictness continuum" (in a one-dimensional product space): This result is obtained through the conjunction of "benevolent preferences" (denominations care about the aggregate utility of members) and asymmetric costs of going to a more or less strict church than one prefers. We also derive implications regarding the relationship between religious strictness and membership. The driving forces of our analysis, religious market interactions and asymmetric costs of membership, high-light new explanations for some well-established stylized facts. The analysis opens the way to new empirical tests, aimed at confronting the implications of our model against more traditional explanations.Location theory, economics of religion

    Unsupervised two-class and multi-class support vector machines for abnormal traffic characterization

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    Although measurement-based real-time traffic classification has received considerable research attention, the timing constraints imposed by the high accuracy requirements and the learning phase of the algorithms employed still remain a challenge. In this paper we propose a measurement-based classification framework that exploits unsupervised learning to accurately categorise network anomalies to specific classes. We introduce the combinatorial use of two-class and multi-class unsupervised Support Vector Machines (SVM)s to first distinguish normal from anomalous traffic and to further classify the latter category to individual groups depending on the nature of the anomaly
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