Penn Engineering

The School of Engineering and Applied Science, established in 1852, is composed of six academic departments and numerous interdisciplinary centers, institutes, and laboratories. At Penn Engineering, we are preparing the next generation of innovative engineers, entrepreneurs and leaders. Our unique culture of cooperation and teamwork, emphasis on research, and dedicated faculty advisors who teach as well as mentor, provide the ideal environment for the intellectual growth and development of well-rounded global citizens.

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Now showing 1 - 10 of 43
  • Publication
    Light Rail Transit Systems: A Definition and Evaluation
    (1972-10-01) Vuchic, Vukan R
    Rail transit represents a family of modes ranging from light rail to regional rapid transit systems and it can be utilized in a number of different cities and types of applications. Many European cities of medium size employ very successfully light rail mode for gradual upgrading of transit service into partially or fully separated high speed, reliable transit systems. Analysis of these cities show that with population densities and auto ownership very similar to those in the United States cities, their transit systems offer a superior service and have much better usage than our cities. Many modern features of light rail technology are not known in this country. Wider use of different rail systems, greatly increased transit financing, introduction of more qualified personnel into transit industry and improved transit planning and implementation procedures are recommended to close the gap in urban transportation between some more progressive European cities and their counterparts in this country.
  • Publication
    Use of High Strength Steel for Hydrogen Containment
    (2007-03-09) Liu, X. Y.; Kameda, Jun A; McMahon, C. J.
    The research involves experiments on model lab heats of an ultra-high-strength steel (high C, low Ni ) and a high-toughness, high-strength steel (high Ni, low C) to determine the limits of toughness as a function of yield strength, grain-boundary purity, and hydrogen fugacity. In addition, the existence and mechanism of brittle intergranular cracking in ideally pure steels is being investigated.
  • Publication
    Light Rail Transit Surface Options
    (1981-12-01) Diamant, E S.; Dondanville, L. A; Hall, J. F; Korve, W. H; Sauve, R. T; Shunk, G. S; Stone, T. J; Vuchic, Vukan R
    Current interest in Light Rail Transit (LRT) is anchored in its functional and economic capabilities which derive from operations at surface street level. European cities have shown that light rail can be successfully co-located with growing automobile traffic. There are no unique forms and approaches to LRT surface operations. European experts have come up with a range of design concepts of varying cost and differing impacts on adjoining vehicular and pedestrian movements. This report reviews and illustrates the applications of many of the more successfully used design and operational concepts. Topics include design concepts using man-made or vegetation barriers to separate traffic and means to delineate and separate movements with contrasting pavement textures and curbs. Considerable coverage is given to use of modern signalized traffic control and traffic management techniques. This report also deals with an essential element of LRT surface operations, self-service or barrier-free fare collection.
  • Publication
    Path Clearance
    (2009-06-01) Likhachev, Maxim; Stentz, Anthony
    In military scenarios, agents (i.e., troops of soldiers, convoys, and unmanned vehicles) may often have to traverse environments with only a limited intelligence about the locations of adversaries. We study a particular instance of this problem that we refer to as path clearance problem.This article presents a survey of our work on scalable and suitable for real-time use approaches to solving the path clearance problem. In particular, in the first part of the article, we show that the path clearance problem exhibits clear preferences on uncertainty. It turns out that these clear preferences can be used to develop an efficient algorithm called probabilistic planning with clear preferences (PPCP). The algorithm is anytime usable, converges to an optimal solution under certain conditions, and scales well to large-scale problems. We briefly describe the PPCP algorithm and show how it can be used to solve the path clearance problem when no scouts are present. In the second part of the article, we show several strategies for how to use the PPCP algorithm in case multiple scouting unmanned aerial vehicles (UAVs) are available. The experimental analysis shows that planning with PPCP results in a substantially smaller execution cost than when ignoring uncertainty, and employing scouts can decrease this execution cost even further.
  • Publication
    Nano Transformations: A Future of Our Making
    (2003-12-08) Bordogna, Joseph
    "Nano" denotes the very small in scale, but there is nothing diminutive about the expectations generated by nanotech--the application of fundamental research at the nanoscale.
  • Publication
    Fabrication of Photonic Crystals with high refractive index
    (2007-03-09) Xu, Yongan; Moon, Jun Hyuk; Yang, Shu; Dan, Yaping; Johnson, Alan T; Perry, Joseph W; Adibi, Ali; Hotchkiss, Peter; Marder, Seth
    • Complete photonic bandgap • High contrast of refractive index (RI) • Polymer material with a low RI • Inorganic material with a higher RI, such as silicon, titania. • Fabrication of diamond-like PCs by MBIL, • Fabrication of high RI inorganic PCs via double templating, • Core-shell morphology of replica • Pinch-off problem • Development of combined level-surface to address pinch-off problem • Electrodeposition of titania 3D structure • Electrophoretic deposition of surface charged nanoparticles
  • Publication
    The Penn Hand-Clapping Motion Dataset
    (2016-11-27) Fitter, Naomi T; Kuchenbecker, Katherine J
    The Penn Hand-Clapping Motion Dataset is composed of inertial measurement unit (IMU) recordings from the hand motions of 15 naïve people. Each of these individuals participated in an experiment during which they were asked to pantomime various sequences of 10 different motions: back five, clap, double, down five, front five, lap pat, left five, right five, right snap, and up five. The examined motions comprise most typical actions from hand-clapping games like “Pat-a-cake” and “Slide.” This project was published in our IROS 2016 paper entitled “Using IMU Data to Demonstrate Hand-Clapping Games to a Robot.” After hearing of interest from other researchers, we are releasing the corresponding motion dataset, which was originally collected to help us investigate whether we could train highly accurate and rapid classifiers to label hand-clapping game motions performed by everyday people. This dataset, explained further in the included ReadMe file, may interest researchers who investigate human motion.
  • Publication
    The Penn Baxter Face Database
    (2017-03-23) Fitter, Naomi T.; Kuchenbecker, Katherine J.
    The Penn Baxter Face Database is composed of Baxter robot face images designed in a variety of expressions and colors. Each of these images was photographed on the physical Baxter robot and assessed by internet raters (N = 568) in an Amazon Mechanical Turk survey. Raters assessed the pleasantness and energeticness of each robot face and also shared how safe and pleased each face made them feel. This project was published in our ICSR 2016 paper entitled “Designing and Assessing Expressive Open-Source Faces for the Baxter Robot.” After hearing of interest from other researchers, we previously released our Baxter face database on GitHub at This dataset, now additionally available on Scholarly Commons, includes the developed Baxter faces, photographs used in the Mechanical Turk survey, editable source files for the studied faces, and bonus faces developed in our subsequent design work with Baxter. These contents may benefit any Baxter users who publish images to the robot's face. The organization of the database is explained in the included ReadMe file.
  • Publication
    Production of Acetaldehyde from Acetic Acid
    (2002-04-09) daRosa, Calvin; Ghatak, Aurindam; Pinto, Claire
    Our group has designed a process to manufacture 101,520,000 lb/yr of acetaldehyde by hydrogenation of acetic acid over a 20% wt. palladium on iron oxide catalyst. The reaction conditions used are the optimum according to a patent filed by Eastman Chemical (Tustin,, U.S. Patent No. 6,121,498): temperature is range is from 557-599 °F at a pressure of 254 psi. The conversion of acetic acid in the reactor is 46 %, with selectivity of 86% to acetaldehyde. Major by-products are ethanol, acetone, carbon dioxide, and the light hydrocarbons methane, ethane, and ethylene. Acetaldehyde is purified in a series of steps: it is first absorbed with an acetic-acid rich solvent, then distilled to separate acetaldehyde from heavier components. A refrigerated condenser is then used to recover additional acetaldehyde from the vapor distillate of the main separation. Acetic acid is purified and recycled to the reactor to limit the amount of feedstock required. Ethyl acetate is produced as a by-product in the acetaldehyde distillation column and is purified and sold. The economics of the process is strongly dependent on the price of acetic acid, and we examined scenarios under which acetic acid was available at either $0.16/lb or $0.12/lb. The total capital investment in either situation is approximately $47,000,000. If acetic acid is available at $0. 16/1b, we estimate an IRR of 11.3 %, but if acetic acid can be purchased for $0.12/Ib the IRR is 18.5% after 20 years. It is our recommendation to pursue more research into projecting both the cost of acetic acid and the market for acetaldehyde. If acetic acid will be available at the lower price, the company should pursue production of acetaldehyde.
  • Publication
    Unifying Confidentiality and Integrity in Downgrading Policies
    (2005-05-13) Zdancewic, Stephan A; Li, Peng
    Confidentiality and integrity are often treated as dual properties in formal models of information-flow control, access control and many other areas in computer security. However, in contrast to confidentiality policies, integrity policies are less formally studied in the information-flow control literature. One important reason is that traditional noninterference-based information-flow control approaches give very weak integrity guarantees for untrusted code. Integrity and confidentiality policies are also different with respect to implicit information channels. This paper studies integrity downgrading policies in information-flow control and compares them with their confidentiality counterparts. We examine the drawbacks of integrity policies based on noninterference formalizations and study the integrity policies in the framework of downgrading policies and program equivalences. We give semantic interpretations for traditional security levels for integrity, namely, tainted and untainted, and explain the interesting relations between confidentiality and integrity in this framework.