135 research outputs found

    SELF-STUDY REPORT Appendix 15: Libraries Faculty Vitae

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    294 page

    Data Structures and Algorithms for Scalable NDN Forwarding

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    Named Data Networking (NDN) is a recently proposed general-purpose network architecture that aims to address the limitations of the Internet Protocol (IP), while maintaining its strengths. NDN takes an information-centric approach, focusing on named data rather than computer addresses. In NDN, the content is identified by its name, and each NDN packet has a name that specifies the content it is fetching or delivering. Since there are no source and destination addresses in an NDN packet, it is forwarded based on a lookup of its name in the forwarding plane, which consists of the Forwarding Information Base (FIB), Pending Interest Table (PIT), and Content Store (CS). In addition, as an in-network caching element, a scalable Repository (Repo) design is needed to provide large-scale long-term content storage in NDN networks. Scalable NDN forwarding is a challenge. Compared to the well-understood approaches to IP forwarding, NDN forwarding performs lookups on packet names, which have variable and unbounded lengths, increasing the lookup complexity. The lookup tables are larger than in IP, requiring more memory space. Moreover, NDN forwarding has a read-write data plane, requiring per-packet updates at line rates. Designing and evaluating a scalable NDN forwarding node architecture is a major effort within the overall NDN research agenda. The goal of this dissertation is to demonstrate that scalable NDN forwarding is feasible with the proposed data structures and algorithms. First, we propose a FIB lookup design based on the binary search of hash tables that provides a reliable longest name prefix lookup performance baseline for future NDN research. We have demonstrated 10 Gbps forwarding throughput with 256-byte packets and one billion synthetic forwarding rules, each containing up to seven name components. Second, we explore data structures and algorithms to optimize the FIB design based on the specific characteristics of real-world forwarding datasets. Third, we propose a fingerprint-only PIT design that reduces the memory requirements in the core routers. Lastly, we discuss the Content Store design issues and demonstrate that the NDN Repo implementation can leverage many of the existing databases and storage systems to improve performance

    2007-2011

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    Trustworthiness in Mobile Cyber Physical Systems

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    Computing and communication capabilities are increasingly embedded in diverse objects and structures in the physical environment. They will link the ‘cyberworld’ of computing and communications with the physical world. These applications are called cyber physical systems (CPS). Obviously, the increased involvement of real-world entities leads to a greater demand for trustworthy systems. Hence, we use "system trustworthiness" here, which can guarantee continuous service in the presence of internal errors or external attacks. Mobile CPS (MCPS) is a prominent subcategory of CPS in which the physical component has no permanent location. Mobile Internet devices already provide ubiquitous platforms for building novel MCPS applications. The objective of this Special Issue is to contribute to research in modern/future trustworthy MCPS, including design, modeling, simulation, dependability, and so on. It is imperative to address the issues which are critical to their mobility, report significant advances in the underlying science, and discuss the challenges of development and implementation in various applications of MCPS

    Characterizing and Mitigating Virtual Machine Interference in Public Clouds.

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    This dissertation studies the mitigation of the performance and security interference between guest virtual machines (VMs) in public clouds. The goals are to characterize the impact of VM interference, uncover the root cause of the negative impact, and design novel techniques to mitigate such impact. The central premise of this dissertation is that by identifying the shared resources that cause the VM interference and by exploiting the properties of the workloads that share these resources with adapted scheduling policies, public cloud services can reduce conflicts of resource usage between guests and hence mitigate their interference. Current techniques for conflict reduction and interference mitigation overlook the virtualization semantic gap between the cloud host infrastructure and guest virtual ma- chines and the unique challenges posed by the multi-tenancy service model necessary to support public cloud services. This dissertation deals with both performance and security interference problems. It characterizes the impact of VM interference on inter-VM network latency using live measurements in a real public cloud and studies the root cause of the negative impact with controlled experiments on a local testbed. Two methods of improving the inter-VM net- work latency are explored. The first approach is a guest-centric solution that exploits the properties of application workloads to avoid interference without any support from the underlying host infrastructure. The second approach is a host-centric solution that adapts the scheduling policies for the contented resources that cause the interference without guest cooperation. Similarly, the characteristics of cache-based cross-VM attacks are studied in detail using both live cloud measurements and testbed experiments. To mitigate this security interference, a partition-based VM scheduling system is designed to reduce the effectiveness of these cache-based attacks.PhDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/107111/1/yunjing_1.pd

    The Trinity Reporter, Fall-Winter 2008

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    https://digitalrepository.trincoll.edu/reporter/2137/thumbnail.jp

    Zylstra v. State Clerk\u27s Record Dckt. 41421

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    https://digitalcommons.law.uidaho.edu/idaho_supreme_court_record_briefs/5777/thumbnail.jp

    Innovator - Summer 2011

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    02 - LIVING IN YOUR GENES Through its nationally ranked physician assistant studies program — led by insightful faculty and an award-winning champion of genetic literacy education — PhilaU is transforming a generation to “think genetically.” 06 - PRESIDENT SPINELLI COMMENTARYNew College structure maximizes students’ experiences 08 - QUIET ON THE SETEmmy-nominated alumna Kim Wannop ’99 dresses six or more sets each week for Fox’s hit TV show Bones. 12 - MEET RON KANDER, PH.D.The executive dean of the College of Design, Engineering and Commerce leads a revolutionary, transdisciplinary curriculum. 18 - NEWS 22 - PROFILES 24 - Q&A WITH BETH FRENCH ’08 Alumna researches cause of autism at Johns Hopkins Hospital 26 - AROUND THE WORLDFaculty and students’ global impact 31 - HONORS AND AWARDS 32 - COLLEGE DEGREES ARE OUTDATEDGuest commentary by Stanford professor and serial entrepreneur Steve Blank touts PhilaU’s groundbreaking approach. 36 - FACULTY ACCOMPLISHMENTS 42 - IN THE NEWS 44 - TOPPING 600 Women’s basketball coach Tom Shirley reached a career mile marker during the 2010-11 season. 46 - ATHLETIC NEWS 54 - ALUMNI EVENTS 59 - CLASS NOTE

    Online learning on the programmable dataplane

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    This thesis makes the case for managing computer networks with datadriven methods automated statistical inference and control based on measurement data and runtime observations—and argues for their tight integration with programmable dataplane hardware to make management decisions faster and from more precise data. Optimisation, defence, and measurement of networked infrastructure are each challenging tasks in their own right, which are currently dominated by the use of hand-crafted heuristic methods. These become harder to reason about and deploy as networks scale in rates and number of forwarding elements, but their design requires expert knowledge and care around unexpected protocol interactions. This makes tailored, per-deployment or -workload solutions infeasible to develop. Recent advances in machine learning offer capable function approximation and closed-loop control which suit many of these tasks. New, programmable dataplane hardware enables more agility in the network— runtime reprogrammability, precise traffic measurement, and low latency on-path processing. The synthesis of these two developments allows complex decisions to be made on previously unusable state, and made quicker by offloading inference to the network. To justify this argument, I advance the state of the art in data-driven defence of networks, novel dataplane-friendly online reinforcement learning algorithms, and in-network data reduction to allow classification of switchscale data. Each requires co-design aware of the network, and of the failure modes of systems and carried traffic. To make online learning possible in the dataplane, I use fixed-point arithmetic and modify classical (non-neural) approaches to take advantage of the SmartNIC compute model and make use of rich device local state. I show that data-driven solutions still require great care to correctly design, but with the right domain expertise they can improve on pathological cases in DDoS defence, such as protecting legitimate UDP traffic. In-network aggregation to histograms is shown to enable accurate classification from fine temporal effects, and allows hosts to scale such classification to far larger flow counts and traffic volume. Moving reinforcement learning to the dataplane is shown to offer substantial benefits to stateaction latency and online learning throughput versus host machines; allowing policies to react faster to fine-grained network events. The dataplane environment is key in making reactive online learning feasible—to port further algorithms and learnt functions, I collate and analyse the strengths of current and future hardware designs, as well as individual algorithms
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