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Medal H.R.,Industrial and Systems Engineering | Pohl E.A.,University of Arkansas | Rossetti M.D.,University of Arkansas
IIE Transactions (Institute of Industrial Engineers) | Year: 2016

We study a new facility protection problem in which one must allocate scarce protection resources to a set of facilities given that allocating resources to a facility only has a probabilistic effect on the facilitys post-disruption capacity. This study seeks to test three common assumptions made in the literature on modeling infrastructure systems subject to disruptions: 1) perfect protection, e.g., protecting an element makes it fail-proof, 2) binary protection, i.e., an element is either fully protected or unprotected, and 3) binary state, i.e., disrupted elements are fully operational or non-operational. We model this facility protection problem as a two-stage stochastic program with endogenous uncertainty. Because this stochastic program is non-convex we present a greedy algorithm and show that it has a worst-case performance of 0.63. However, empirical results indicate that the average performance is much better. In addition, experimental results indicate that the mean-value version of this model, in which parameters are set to their mean values, performs close to optimal. Results also indicate that the perfect and binary protection assumptions together significantly affect the performance of a model. On the other hand, the binary state assumption was found to have a smaller effect. © 2015 "IIE". Source


News Article
Site: http://phys.org/technology-news/

That's according to a new University at Buffalo study that explores security vulnerabilities of 3-D printing, also called additive manufacturing, which analysts say will become a multibillion-dollar industry employed to build everything from rocket engines to heart valves. "Many companies are betting on 3-D printing to revolutionize their businesses, but there are still security unknowns associated with these machines that leave intellectual property vulnerable," said Wenyao Xu, PhD, assistant professor in UB's Department of Computer Science and Engineering, and the study's lead author. Xu and collaborators will present the research, "My Smartphone Knows What You Print: Exploring Smartphone-based Side-channel Attacks Against 3D Printers," at the Association for Computing Machinery's 23rd annual Conference on Computer and Communications Security in October in Austria. Unlike most security hacks, the researchers did not simulate a cyberattack. Many 3-D printers have features, such as encryption and watermarks, designed to foil such incursions. Instead, the researchers programmed a common smartphone's built-in sensors to measure electromagnetic energy and acoustic waves that emanate from 3-D printers. These sensors can infer the location of the print nozzle as it moves to create the three-dimensional object being printed. The smartphone, at 20 centimeters away from the printer, gathered enough data to enable the researchers to replicate printing a simple object, such as a door stop, with a 94 percent accuracy rate. For complex objects, such as an automotive part or medical device, the accuracy rate was lower but still above 90 percent. "The tests show that smartphones are quite capable of retrieving enough data to put sensitive information at risk," says Kui Ren, PhD, professor in UB's Department of Computer Science and Engineering, a co-author of the study. The richest source of information came from electromagnetic waves, which accounted for about 80 percent of the useful data. The remaining data came from acoustic waves. Ultimately, the results are eye-opening because they show how anyone with a smartphone—from a disgruntled employee to an industrial spy—might steal intellectual property from an unsuspecting business, especially "mission critical" industries where one breakdown of a system can have a serious impact on the entire organization. "Smartphones are so common that industries may let their guard down, thus creating a situation where intellectual property is ripe for theft," says Chi Zhou, PhD, assistant professor in UB's Department of Industrial and Systems Engineering, another study co-author. The researchers suggests several ways to make 3-D printing more secure. Perhaps the simplest deterrent from such an attack is distance. The ability to obtain accurate data for simple objects diminished to 87 percent at 30 centimeters, and 66 percent at 40 centimeters, according to the study. Another option is to increase the print speed. The researchers said that emerging materials may allow 3-D printers to work faster, thus making it more difficult for smartphone sensors to determine the print nozzle's movement. Other ideas include software-based solutions, such as programming the printer to operate at different speeds, and hardware-based ideas, such as acoustic and electromagnetic shields. Explore further: HP injecting Internet technology into new printers


Navarro E.N.,Industrial and Systems Engineering | Bourguet R.E.,Industrial and Systems Engineering | Aceves N.,Industrial and Systems Engineering | Garza J.,Cemex
61st Annual IIE Conference and Expo Proceedings | Year: 2011

This paper shows the design and development of a knowledge transfer tool. Specifically, to transfer design concepts on how to build simulation-based decision support systems for operational planning in a concrete order fulfillment process. The tool is based on self-directed learning methodology, interactive design principles, and supported by the computational package iThink. Design concepts to be transferred correspond to logical-discrete structures of a simulation model of more than 4000 variables. The simulator represents logistics knowledge at the execution level, and thus it supports minute-hourly basis decisions. The tool responds to a demand for disseminating best practices in a global organization. It is a result of a joined university-industry research effort to reinforce knowledge management capabilities in both entities. Foundations, design criteria, and detail of main results on the design and development process for the knowledge transfer tool are described. Finally, conclusions and future works are included. Source


Cogswell J.T.,Industrial and Systems Engineering | Li P.,Industrial and Systems Engineering | Faghri M.,Industrial and Systems Engineering
2010 14th International Heat Transfer Conference, IHTC 14 | Year: 2010

Rapid mixing of two fluids in microchannels has posed an important challenge to the development of many integrated lab-on-a-chip systems. In this paper, we present a planar labyrinth micromixer (PLM) to achieve rapid and passive mixing by taking advantage of a synergistic combination of the Dean vortices in curved channels, a series of perturbation to the fluids from the sharp turns, and an expansion and contraction of the flow field via a circular chamber. The PLM is constructed in a single soft lithography step and the labyrinth has a footprint of 7.32 mm x 7.32 mm. Experiments using fluorescein isothiocyanate solutions and deionized water demonstrate that the design achieves fast and uniform mixing within 9.8 s to 32 ms for Reynolds numbers between 2.5 and 30. Compared to the mixing in the prevalent serpentine design, our design results in 38% and 79% improvements on the mixing efficiency at Re=5 and Re=30 respectively. An inverse relationship between mixing length and mass transfer Péclet number (Pe) is observed, which is superior to the logarithmic dependence of mixing length on Pe in chaotic mixers. Having a simple planar structure, the PLM can be easily integrated into lab-on-a-chip devices where passive mixing is needed. © 2010 by ASME. Source


Lockhart T.E.,Industrial and Systems Engineering | Lockhart T.E.,Wake forest University | Soangra R.,Industrial and Systems Engineering | Soangra R.,Wake forest University | And 2 more authors.
50th Annual Rocky Mountain Bioengineering Symposium and 50th International ISA Biomedical Sciences Instrumentation Symposium 2013 | Year: 2013

Mobility characteristics associated with activity of daily living such as sitting down, lying down, rising up, and walking are considered to be important in maintaining functional independence and healthy life style especially for the growing elderly population. Characteristics of postural transitions such as sit-to-stand are widely used by clinicians as a physical indicator of health, and walking is used as an important mobility assessment tool. Many tools have been developed to assist in the assessment of functional levels and to detect a person's activities during daily life. These include questionnaires, observation, diaries, kinetic and kinematic systems, and validated functional tests. These measures are costly and time consuming, rely on subjective patient recall and may not accurately reflect functional ability in the patient's home. In order to provide a low-cost, objective assessment of functional ability, inertial measurement unit (IMU) using MEMS technology has been employed to ascertain ADLs. These measures facilitate long-term monitoring of activity of daily living using wearable sensors. IMU system are desirable in monitoring human postures since they respond to both frequency and the intensity of movements and measure both dc (gravitational acceleration vector) and ac (acceleration due to body movement) components at a low cost. This has enabled the development of a small, lightweight, portable system that can be worn by a free-living subject without motion impediment - TEMPO (Technology Enabled Medical Precision Observation). Using this IMU system, we acquired indirect measures of biomechanical variables that can be used as an assessment of individual mobility characteristics with accuracy and recognition rates that are comparable to the modern motion capture systems. In this study, five subjects performed various ADLs and mobility measures such as posture transitions and gait characteristics were obtained. We developed postural event detection and classification algorithm using denoised signals from single wireless IMU placed at sternum. The algorithm was further validated and verified with motion capture system in laboratory environment. Wavelet denoising highlighted postural events and transition durations that further provided clinical information on postural control and motor coordination. The presented method can be applied in real life ambulatory monitoring approaches for assessing condition of elderly. © 2013 by ISA - instrumentation Systems & Automation Society. Source

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