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Park H.J.,5Water Street | Roess R.P.,Metrotech Center
Procedia Computer Science | Year: 2015

On-ramp junctions on freeways are subject to vehicle merging interactions between main travel lanes and ramp flows. The turbulence created by these interactions often causes congestion, and can lead to breakdown when the combined volume from the ramp and the mainline exceed the capacity of the downstream freeway segment. This study discusses a potential application for freeway control policy at the ramp junction-The Lane Operation Restriction (LOR) policy. This policy would provide particular attention to traffic operation improvements at on-ramp junctions with relatively high flow rates from the ramp. Principles of LOR policy would be based on empirical data and analysis findings. The empirical data are analyzed upstream and downstream of on-ramp junctions on six-lane freeways using a database for the National Cooperative Highway Research Program (NCHRP) 3-37. It was observed that lanes 2 (middle lane) and 3 (median side lane) show a higher density-speed relationship than the shoulder lane upstream of the junctions. In addition, the breakdown condition and congestion spread across all freeway travel lanes when the flow of lane 1 (shoulder side lane) is suddenly increased to near capacity at the ramp influence areas. A simulation analysis employing the LOR policy is introduced evaluating the ramp junction influence areas, its downstream and upstream areas. It concludes that traffic operations in the vicinity of on-ramp junctions can be significantly improved when upstream vehicles are guided to shift from lane 1 to lanes 2 and 3 before arriving at on-ramp junctions and restraint lane changes at the ramp influence area. © 2015 The Authors. Published by Elsevier B.V. Source

Panciroli R.,University Niccolo Cusano | Porfiri M.,Metrotech Center
Procedia Engineering | Year: 2014

In this work, a non-intrusive pressure reconstruction method based on particle image velocimetry (PIV) is utilized to investigate hydroelastic phenomena associated with the water entry of flexible structures. Experiments are conducted on flexible cantilevered wedges entering the water in free fall. PIV is leveraged to evaluate the effect of the mutual interaction between the fluid flow and structural deformation on the distributed hydrodynamic loading. The wedge compliance is found to strongly influence the hydrodynamic loading, resulting into marked oscillations in the distribution and evolution of the pressure on the wetted surface of the impacting body. © 2014 The Authors. Published by Elsevier Ltd. Source

Dottori S.,University of Rome Tor Vergata | Flamini V.,Metrotech Center | Vairo G.,University of Rome Tor Vergata
International Journal of Computational Methods in Engineering Science and Mechanics | Year: 2016

ABSTRACT: In this paper stents employed to treat peripheral artery disease are analyzed through a three-dimensional finite-element approach, based on a large-strain and large-displacement formulation. Aiming to evaluate the influence of some stent design parameters on stent mechanics and on the biomechanical interaction between stent and arterial wall, quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercially and noncommercially available versions of both braided self-expandable stents and balloon-expandable stents. Addressing isolated device models, opening mechanisms and flexibility of both opened and closed stent configurations are numerically experienced. Moreover, stent deployment into a stenotic peripheral artery and possible postdilatation angioplasty (the latter for the self-expandable device only) are simulated by considering different idealized vessel geometries and accounting for the presence of a stenotic plaque. Proposed results highlight important differences in the mechanical response of the two types of stents, as well as a significant influence of the vessel shape on the stress distributions arising upon the artery-plaque system. Finally, computational results are used to assess both the stent mechanical performance and the effectiveness of the stenting treatment, allowing also to identify possible critical conditions affecting the risk of stent fracture, tissue damage, and/or pathological tissue response. © 2016 Taylor & Francis Group, LLC. Source

Brizan D.G.,The Graduate Center, CUNY | Gallagher K.,Metrotech Center | Jahangir A.,CUNY - Hunter College | Brown T.,The Graduate Center, CUNY
Scientometrics | Year: 2016

Definitions for influence in bibliometrics are surveyed and expanded upon in this work. On data composed of the union of DBLP and CiteSeerx, approximately 6 million publications, a relatively small number of features are developed to describe the set, including loyalty and community longevity, two novel features. These features are successfully used to predict the influential set of papers in a series of machine learning experiments. The most predictive features are highlighted and discussed. © 2016 Akadémiai Kiadó, Budapest, Hungary Source

Freese J.P.,Metrotech Center | Jorgenson D.B.,Philips | Liu P.-Y.,Fred Hutchinson Cancer Research Center | Innes J.,London Ambulance Service | And 7 more authors.
Circulation | Year: 2013

BACKGROUND - Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. METHODS AND RESULTS - In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P=0.70; sustained ROSC, 32.4% versus 33.4%, P=0.79; survival to admission, 34.1% versus 36.4%, P=0.46; survival to hospital discharge, 15.6% versus 17.2%, P=0.55, respectively). CONCLUSIONS - Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF. © 2013 American Heart Association, Inc. Source

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