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 35
  • Publication
    Authoring Multi-Actor Behaviors in Crowds With Diverse Personalities
    (2013-01-01) Kapadia, Mubbasir; Shoulson, Alexander; Durupinar, Funda; Badler, Norman I
    Multi-actor simulation is critical to cinematic content creation, disaster and security simulation, and interactive entertainment. A key challenge is providing an appropriate interface for authoring high-fidelity virtual actors with featurerich control mechanisms capable of complex interactions with the environment and other actors. In this chapter, we present work that addresses the problem of behavior authoring at three levels: Individual and group interactions are conducted in an event-centric manner using parameterized behavior trees, social crowd dynamics are captured using the OCEAN personality model, and a centralized automated planner is used to enforce global narrative constraints on the scale of the entire simulation. We demonstrate the benefits and limitations of each of these approaches and propose the need for a single unifying construct capable of authoring functional, purposeful, autonomous actors which conform to a global narrative in an interactive simulation.
  • Publication
    The Role of Reflexes Versus Central Pattern Generators
    (2002-01-01) Klavins, Eric; Komsuoglu, Haldun; Full, Robert J; Koditschek, Daniel E
    Animals execute locomotor behaviors and more with ease. They have evolved these breath-taking abilities over millions of years. Cheetahs can run, dolphins can swim and flies can fly like no artificial technology can. It is often argued that if human technology could mimic nature, then biological-like performance would follow. Unfortunately, the blind copying or mimicking of a part of nature [Ritzmann et al., 2000] does not often lead to the best design for a variety of reasons [Vogel, 1998]. Evolution works on the "just good enough" principle. Optimal designs are not the necessary end product of evolution. Multiple satisfactory solutions can result in similar performances. Animals do bring to our attention amazing designs, but these designs carry with them the baggage of their history. Moreover, natural design is constrained by factors that may have no relationship to human engineered designs. Animals must be able to grow over time, but still function along the way. Finally, animals are complex and their parts serve multiple functions, not simply the one we happen to examine. In short, in their daunting complexity and integrated function, understanding animal behaviors remains as intractable as their capabilities are tantalizing.
  • Publication
    Transportation for Liveable Cities: Problems, Obstacles, and Successful Solutions
    (2010-01-01) Vuchic, Vukan R
    This chapter focuses on urban transportation. It is written by the moderator of the session on Land Transportation. He asked the five speakers to report on positive achievements and challenges in their cities or countries. The chapter starts with the moderator's review of developments and trends in urban transportation and a summary of the five reports by participants presented in the session. It is followed by a brief review of the conditions in urban transportation and its impact on cities. Following a review of problems most cities face and mistakes in transportation planning many cities continue to make, this chapter places emphasis on progressive policies and successful solutions which feasibility has been demonstrated by a number of leading cities.
  • Publication
    Lower Bounds for Quantile Estimation in Random-Order and Multi-Pass Streaming
    (2007-08-26) Guha, Sudipto; McGregor, Andrew
    We present lower bounds on the space required to estimate the quantiles of a stream of numerical values. Quantile estimation is perhaps the most studied problem in the data stream model and it is relatively well understood in the basic single-pass data stream model in which the values are ordered adversarially. Natural extensions of this basic model include the random-order model in which the values are ordered randomly (e.g. [21,5,13,11,12]) and the multi-pass model in which an algorithm is permitted a limited number of passes over the stream (e.g. [6,7,1,19,2,6,7,19,2]). We present lower bounds that complement existing upper bounds [21,11] in both models. One consequence is an exponential separation between the random-order and adversarial-order models: using Ω(polylog n) space, exact selection requires Ω(log n) passes in the adversarial-order model while O(loglog n) passes are sufficient in the random-order model.
  • Publication
    Process-Algebraic Analysis of Timing and Schedulability Properties
    (2006-09-19) Philippou, Anna; Sokolsky, Oleg
    In this chapter, we present an overview of how timing information can be embedded in process-algebraic frameworks. We concentrate on the case of discrete-time modeling. We begin by discussing design approaches that have been adopted in different formalisms to model time and time passage, and how the resulting mechanisms interact with one another and with standard untimed process-algebraic operators. We proceed to give an overview of ACSR, a timed process algebra developed for modeling and reasoning about timed, resource-constrained systems. In doing this, ACSR adopts the notion of a resource as a first-class entity, and it replaces maximal progress, employed by other timed process algebras, by the notion of resource-constrained progress. ACSR associates resource-usage with time passage, and implements appropriate semantic rules to ensure that progress in the system is enforced as far as possible while simultaneous usage of a resource by distinct processes is excluded. In addition, ACSR employs the notion of priorities to arbitrate access to resources by competing processes. Finally, we illustrate the use of ACSR for the schedulability analysis of a realistic real-time system problem.
  • Publication
    Runtime verification of parametric properties using SMEDL
    (2019-09-01) Zhang, Teng; Kaur, Ramneet; Lee, Insup; Sokolsky, Oleg
    Parametric properties are typical properties to be checked in runtime verification (RV). As a common technique for parametric monitoring, trace slicing divides an execution trace into a set of sub traces which are checked against non-parametric base properties. An efficient trace slicing algorithm is implemented in MOP. Another RV technique, QEA further allows for nested use of universal and existential quantification over parameters. In this paper, we present a methodology for parametric monitoring using the RV framework SMEDL. Trace slicing algorithm in MOP can be expressed by execution of a set of SMEDL monitors. Moreover, the semantics of nested quantifiers is encoded by a hierarchy of monitors for aggregating verdicts of sub traces. Through case studies, we demonstrate that SMEDL provides a natural way to monitor parametric properties with more potentials for flexible deployment and optimizations.
  • Publication
    Affordances in AI
    (2012-01-01) Nye, Benjamin D.; Silverman, Barry G
    Affordances in AI refer to a design methodology for creating artificial intelligence systems that are designed to perceive their environment in terms of its affordances (Sahin et al. 2007). Affordances in AI are adapted from affordances introduced in The Ecological Approach to Visual Perception by James J. Gibson (1979). Design methodologies in the applied sciences use affordances to represent potential actions that exist as a relationship between an agent and its environment. This approach to artificial intelligence is designed for autonomous agents, making it suitable for robotics and simulation.
  • Publication
    Javni Gradski Promet: Sistemi i Tehnologija
    (1982-03-01) Vuchic, Vukan R
  • Publication
    Visual Attention and Eye Gaze During Multiparty Conversations with Distractions
    (2006-08-10) Gu, Erdan; Badler, Norman I
    Our objective is to develop a computational model to predict visual attention behavior for an embodied conversational agent. During interpersonal interaction, gaze provides signal feedback and directs conversation flow. Simultaneously, in a dynamic environment, gaze also directs attention to peripheral movements. An embodied conversational agent should therefore employ social gaze not only for interpersonal interaction but also to possess human attention attributes so that its eyes and facial expression portray and convey appropriate distraction and engagement behaviors.
  • Publication
    Planning for Animation
    (1996-08-01) Badler, Norman I; Webber, Bonnie L; Becket, Welton; Geib, Christopher W; Moore, Michael B; Pelachaud, Catherine; Reich, Barry D; Stone, Matthew