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Articles 32611 - 32640 of 40977

Full-Text Articles in Engineering

Design And Evaluation Of Packet Classification Systems, Doctoral Dissertation, December 2006, Haoyu Song Jan 2006

Design And Evaluation Of Packet Classification Systems, Doctoral Dissertation, December 2006, Haoyu Song

All Computer Science and Engineering Research

Although many algorithms and architectures have been proposed, the design of efficient packet classification systems remains a challenging problem. The diversity of filter specifications, the scale of filter sets, and the throughput requirements of high speed networks all contribute to the difficulty. We need to review the algorithms from a high-level point-of-view in order to advance the study. This level of understanding can lead to significant performance improvements. In this dissertation, we evaluate several existing algorithms and present several new algorithms as well. The previous evaluation results for existing algorithms are not convincing because they have not been done in …

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Manifold Learning For Natural Image Sets, Doctoral Dissertation August 2006, Richard Souvenir Jan 2006

Manifold Learning For Natural Image Sets, Doctoral Dissertation August 2006, Richard Souvenir

All Computer Science and Engineering Research

The field of manifold learning provides powerful tools for parameterizing high-dimensional data points with a small number of parameters when this data lies on or near some manifold. Images can be thought of as points in some high-dimensional image space where each coordinate represents the intensity value of a single pixel. These manifold learning techniques have been successfully applied to simple image sets, such as handwriting data and a statue in a tightly controlled environment. However, they fail in the case of natural image sets, even those that only vary due to a single degree of freedom, such as a …

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A Thesis On Sketch-Based Techniques For Mesh Deformation And Editing, Raquel Bujans Jan 2006

A Thesis On Sketch-Based Techniques For Mesh Deformation And Editing, Raquel Bujans

All Computer Science and Engineering Research

The goal of this research is to develop new and more intuitive ways for editing a mesh from a static camera angle. I present two ways to edit a mesh via a simple sketching system. The first method is a gray-scale editor which allows the user to specify a fall off function for the region being deformed. The second method is a profile editor in which the user can re-sketch a mesh’s profile. Lastly, the types of edits possible will be discussed and our results will be presented.

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Unified Power Management In Wireless Sensor Networks, Doctoral Dissertation, August 2006, Guoliang Xing Jan 2006

Unified Power Management In Wireless Sensor Networks, Doctoral Dissertation, August 2006, Guoliang Xing

All Computer Science and Engineering Research

Radio power management is of paramount concern in wireless sensor networks (WSNs) that must achieve long lifetimes on scarce amount of energy. Previous work has treated communication and sensing separately, which is insufficient for a common class of sensor networks that must satisfy both sensing and communication requirements. Furthermore, previous approaches focused on reducing energy consumption in individual radio states resulting in suboptimal solutions. Finally, existing power management protocols often assume simplistic models that cannot accurately reflect the sensing and communication properties of real-world WSNs. We develop a unified power management approach to address these issues. We first analyze the …

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A Unified Architecture For Flexible Radio Power Management In Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu Jan 2006

A Unified Architecture For Flexible Radio Power Management In Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu

All Computer Science and Engineering Research

A challenge for many wireless sensor networks is to remain operational for long periods of time on a very limited power supply. While many power management protocols have been proposed, a solution does not yet exist that allows them to be seamlessly integrated into the existing systems. In this paper we study the architectural support required to resolve this issue. We propose a framework that separates sleep scheduling from the basic MAC layer functionality and provide a set of unified interfaces between them. This framework enables different sleep scheduling policies to be easily implemented on top of multiple MAC layers. …

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Use Of Gene Expression Profiling And Machine Learning To Understand And Predict Primary Graft Dysfunction, Monika Ray, Sekhar Dharmarajan, Johannes Freudenberg, Weixiong Zhang, Alexander G. Patterson Jan 2006

Use Of Gene Expression Profiling And Machine Learning To Understand And Predict Primary Graft Dysfunction, Monika Ray, Sekhar Dharmarajan, Johannes Freudenberg, Weixiong Zhang, Alexander G. Patterson

All Computer Science and Engineering Research

No abstract provided.

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Extending Byzantine Fault Tolerance To Replicated Clients, Ian Wehrman, Sajeeva L. Pallemulle, Kenneth J. Goldman Jan 2006

Extending Byzantine Fault Tolerance To Replicated Clients, Ian Wehrman, Sajeeva L. Pallemulle, Kenneth J. Goldman

All Computer Science and Engineering Research

Byzantine agreement protocols for replicated deterministic state machines guarantee that externally requested operations continue to execute correctly even if a bounded number of replicas fail in arbitrary ways. The state machines are passive, with clients responsible for any active ongoing application behavior. However, the clients are unreplicated and outside the fault-tolerance boundary. Consequently, agreement protocols for replicated state machines do not guarantee continued correct execution of long-running client applications. Building on the Castro and Liskov Byzantine Fault Tolerance protocol for unreplicated clients (CLBFT), we present a practical algorithm for Byzantine fault-tolerant execution of long-running distributed applications in which replicated deterministic …

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Limit Crossing For Decision Problems, Sharlee Climer, Weixiong Zhang Jan 2006

Limit Crossing For Decision Problems, Sharlee Climer, Weixiong Zhang

All Computer Science and Engineering Research

Limit crossing is a methodology in which modified versions of a problem are solved and compared, yielding useful information about the original problem. Pruning rules that are used to exclude portions of search trees are excellent examples of the limit-crossing technique. In our previous work, we examined limit crossing for optimization problems. In this paper, we extend this methodology to decision problems. We demonstrate the use of limit crossing in our design of a tool for identifying K-SAT backbones. This tool is guaranteed to identify all of the backbone variables by solving at most n+1 formulae, where n is the …

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Automatic Application-Specific Customization Of Softcore Processor Microarchitecture, Masters Thesis, May 2006, Shobana Padmanabhan Jan 2006

Automatic Application-Specific Customization Of Softcore Processor Microarchitecture, Masters Thesis, May 2006, Shobana Padmanabhan

All Computer Science and Engineering Research

Applications for constrained embedded systems are subject to strict runtime and resource utilization bounds. With soft core processors, application developers can customize the processor for their application, constrained by available hardware resources but aimed at high application performance. The more reconfigurable the processor is, the more options the application developers will have for customization and hence increased potential for improving application performance. However, such customization entails developing in-depth familiarity with all the parameters, in order to configure them effectively. This is typically infeasible, given the tight time-to-market pressure on the developers. Alternatively, developers could explore all possible configurations, but being …

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Virtualizing Network Processors, Ben Wun, Jonathan Turner, Patrick Crowley Jan 2006

Virtualizing Network Processors, Ben Wun, Jonathan Turner, Patrick Crowley

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This paper considers the problem of virtualizing the resources of a network processor (NP) in order to allow multiple third-parties to execute their own virtual router software on a single physical router at the same time. Our broad interest is in designing such a router capable of supporting virtual networking. We discuss the issues and challenges involved in this virtualization, and then describe specific techniques for virtualizing both the control and data-plane processors on NPs. For Intel IXP NPs in particular, we present a dynamic, macro-based technique for virtualization that allows multiple virtual routers to run on multiple data plane …

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A Proposed Architecture For The Geni Backbone Platform, Jonathan Turner Jan 2006

A Proposed Architecture For The Geni Backbone Platform, Jonathan Turner

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The GENI Project (Global Environment for Network Innovation) is a major NSF-sponsored initiative that seeks to create a national research facility to enable experimental deployment of innovative new network architectures on a sufficient scale to enable realistic evaluation. One key component of the GENI system will be the GENI Backbone Platform (GBP) that provides the resources needed to allow multiple experimental networks to co-exist within the shared GENI infrastructure. This report reviews the objectives for the GBP, reviews the key issues that affect its design and develops a detailed reference architecture in order to provide a concrete example for how …

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Agilla: A Mobile Agent Middleware For Sensor Networks, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu Jan 2006

Agilla: A Mobile Agent Middleware For Sensor Networks, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu

All Computer Science and Engineering Research

Agilla is a mobile agent middleware for sensor networks. Mobile agents are special processes that can migrate across sensors. They increase network flexibility by enabling active in-network reprogramming. Neighbor lists and tuple spaces are used for agent coordination. Agilla was originally implemented on Mica2 motes, but has been ported to other platforms. Its Mica2 implementation consumes 41.6KB of code and 3.59KB of data memory. Agents can move five hops in less than 1.1s with over 92% success. Agilla was used to develop multiple applications related to fire detection and tracking, cargo container monitoring, and robot navigation.

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Acceleration Of Profile-Hmm Search For Protein Sequences In Reconfigurable Hardware - Master's Thesis, May 2006 , Rahul Pratap Maddimsetty Jan 2006

Acceleration Of Profile-Hmm Search For Protein Sequences In Reconfigurable Hardware - Master's Thesis, May 2006 , Rahul Pratap Maddimsetty

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Profile Hidden Markov models are highly expressive representations of functional units, or motifs, conserved across protein sequences. Profile-HMM search is a powerful computational technique that is used to annotate new sequences by identifying occurrences of known motifs in them. With the exponential growth of protein databases, there is an increasing demand for acceleration of such techniques. We describe an accelerator for the Viterbi algorithm using a two-stage pipelined design in which the first stage is implemented in parallel reconfigurable hardware for greater speedup. To this end, we identify algorithmic modifications that expose a high level of parallelism and characterize their …

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Fair Efficiency, Or Low Average Delay Without Starvation, Christoph Jechlitschek, Sergey Gorinksky Jan 2006

Fair Efficiency, Or Low Average Delay Without Starvation, Christoph Jechlitschek, Sergey Gorinksky

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Elastic applications are primarily interested in minimal delay achievable for their messages under current network load. In this paper, we investigate how to transmit such messages over a bottleneck link efficiently and fairly.

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The Meta-Theory Of Q_0 In The Calculus Of Inductive Constructions, Master's Thesis, May 2006, Li-Yang Tan Jan 2006

The Meta-Theory Of Q_0 In The Calculus Of Inductive Constructions, Master's Thesis, May 2006, Li-Yang Tan

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The notion of a proof is central to all of mathematics. In the language of formal logic, a proof is a finite sequence of inferences from a set of axioms, and any statement one yields from such a finitistic procedure is called a theorem. For better or for worse, this is far from the form a traditional mathematical proof takes. Mathematicians write proofs that omit routine logical steps, and details deemed tangential to the central result are often elided. These proofs are fuzzy and human-centric, and a great amount of context is assumed on the part of the reader. While …

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Control Of Decoherence In Open Quantum Systems, Narayan Ganesan Jan 2006

Control Of Decoherence In Open Quantum Systems, Narayan Ganesan

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No abstract provided.

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Dynamic Conflict-Free Query Scheduling For Wireless Sensor Networks, Octav Chipara, Chenyang Lu, John Stankovic Jan 2006

Dynamic Conflict-Free Query Scheduling For Wireless Sensor Networks, Octav Chipara, Chenyang Lu, John Stankovic

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With the emergence of high data rate sensor network applications, there is an increasing demand for high-performance query services in such networks. To meet this challenge, we present Dynamic Conflict-free Query Scheduling (DCQS), a novel scheduling technique for queries in wireless sensor networks. In contrast to earlier TDMA protocols designed for general-purpose networks and workloads, DCQS is specifically designed for query services supporting in-network data aggregation. DCQS has several important features. First, it optimizes the query performance and energy efficiency by exploiting the temporal properties and precedence constraints introduced by data aggregation. Second, it can efficiently adapt to dynamic workloads …

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Reusable Models For Timing And Liveness Analysis Of Middleware For Distributed Real-Time And Embedded Systems, Venkita Subramonian, Christopher Gill, Cesar Sanchez, Henny Sipma Jan 2006

Reusable Models For Timing And Liveness Analysis Of Middleware For Distributed Real-Time And Embedded Systems, Venkita Subramonian, Christopher Gill, Cesar Sanchez, Henny Sipma

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Distributed real-time and embedded (DRE) systems have stringent constraints on timeliness and other properties whose assurance is crucial to correct system behavior. Formal tools and techniques play a key role in verifying and validating system properties. However, many DRE systems are built using middleware frameworks that have grown increasingly complex to address the diverse requirements of a wide range of applications. How to apply formal tools and techniques effectively to these systems, given the range of middleware configuration options available, is therefore an important research problem. This paper makes three contributions to research on formal verification and validation of middleware-based …

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Distributed Utilization Control For Real-Time Clusters With Load Balancing, Yong Fu, Hongan Wang, Chenyang Lu, Ramu S. Chandra Jan 2006

Distributed Utilization Control For Real-Time Clusters With Load Balancing, Yong Fu, Hongan Wang, Chenyang Lu, Ramu S. Chandra

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Recent years have seen rapid growth of online services that rely on large-scale server clusters to handle high volume of requests. Such clusters must adaptively control the CPU utilizations of many processors in order to maintain desired soft real-time performance and prevent system overload in face of unpredictable workloads. This paper presents DUC-LB, a novel distributed utilization control algorithm for cluster-based soft real-time applications. Compared to earlier works on utilization control, a distinguishing feature of DUC-LB is its capability to handle system dynamics caused by load balancing, which is a common and essential component of most clusters today. Simulation results …

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Real-Time Memory Management: Life And Times, Andrew Borg, Andy Wellings, Christopher Gill, Ron K. Cytron Jan 2006

Real-Time Memory Management: Life And Times, Andrew Borg, Andy Wellings, Christopher Gill, Ron K. Cytron

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As high integrity real-time systems become increasingly large and complex, forcing a static model of memory usage becomes untenable. The challenge is to provide a dynamic memory model that guarantees tight and bounded time and space requirements without overburdening the developer with memory concerns. This paper provides an analysis of memory management approaches in order to characterise the tradeoffs across three semantic domains: space, time and a characterisation of memory usage information such as the lifetime of objects. A unified approach to distinguishing the merits of each memory model highlights the relationship across these three domains, thereby identifying the class …

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Cian: A Language And Middleware For Collaboration In Ad Hoc Networks, Rohan Sen, Gruia-Catalin Roman, Andrew Frank Jan 2006

Cian: A Language And Middleware For Collaboration In Ad Hoc Networks, Rohan Sen, Gruia-Catalin Roman, Andrew Frank

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Designing software that supports collaboration among multiple users in mobile ad hoc networks is challenging due to the dynamic network topology and inherent unpredictability of the environment. However, as we increasingly migrate to using mobile computing platforms, there is a pertinent need for software that can support a wide range of collaborative activities anywhere and at any time without relying on any external infrastructure. In this paper, we adopt the workflow model to represent the structure of an activity that involves multiple tasks being performed in a structured, collaborative fashion by multiple users. Using the workflow model as a base, …

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Towards A Unified Radio Power Management Architecture For Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu Jan 2006

Towards A Unified Radio Power Management Architecture For Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu

All Computer Science and Engineering Research

In many wireless sensor networks, energy is an extremely limited resource. While many different power management strategies have been proposed to help reduce the amount of energy wasted, application developers still face two fundamental challenges when developing systems with stringent power constraints. First, existing power management strategies are usually tightly coupled with network protocols and other system functionality. This monolithic approach has led to standalone solutions that cannot easily be reused or extended to other applications or platforms. Second, different power management strategies make different and sometimes even conflicting assumptions about the rest of the system with which they need …

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Link Layer Support For Unified Radio Power Management In Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu Jan 2006

Link Layer Support For Unified Radio Power Management In Wireless Sensor Networks, Kevin Klues, Guoliang Xing, Chenyang Lu

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Radio power management is of paramount concern in wireless sensor networks that must achieve long lifetimes on scarce amounts of energy. While a multitude of power management protocols have been proposed in the past, the lack of system support for flexibly integrating them with a diverse set of applications and network platforms has made them difficult to use. Instead of proposing yet another power management protocol, this paper focuses on providing link layer support towards realizing a Unified Power Management Architecture (UPMA) for flexible radio power management in wireless sensor networks. In contrast to the monolithic approaches adopted by existing …

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Design Of Routers For Diversified Networks, Jonathan Turner Jan 2006

Design Of Routers For Diversified Networks, Jonathan Turner

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No abstract provided.

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Ceg 490/690-01: Technology-Based Ventures, Forouzan Golshani, S. Narayanan Jan 2006

Ceg 490/690-01: Technology-Based Ventures, Forouzan Golshani, S. Narayanan

Computer Science & Engineering Syllabi

No abstract provided.

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Cs 205-04,05,06: Computer Literacy And Office Automation, Terri Bauer Jan 2006

Cs 205-04,05,06: Computer Literacy And Office Automation, Terri Bauer

Computer Science & Engineering Syllabi

No abstract provided.

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Development And Implementation Of Optimized Energy-Delay Sub-Network Routing Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda Jan 2006

Development And Implementation Of Optimized Energy-Delay Sub-Network Routing Protocol For Wireless Sensor Networks, Maciej Jan Zawodniok, Jagannathan Sarangapani, Steve Eugene Watkins, James W. Fonda

Electrical and Computer Engineering Faculty Research & Creative Works

The development and implementation of the optimized energy-delay sub-network routing (OEDSR) protocol for wireless sensor networks (WSN) is presented. This ondemand routing protocol minimizes a novel link cost factor which is defined using available energy, end-to-end (E2E) delay and distance from a node to the base station (BS), along with clustering, to effectively route information to the BS. Initially, the nodes are either in idle or sleep mode, but once an event is detected, the nodes near the event become active and start forming sub-networks. Formation of the inactive network into a sub-network saves energy because only a portion of …

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Distributed Power Control For Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani Jan 2006

Distributed Power Control For Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel distributed power control (DPC) scheme for cellular network in the presence of radio channel uncertainties such as path loss, shadowing, and Rayleigh fading is presented. Since these uncertainties can attenuate the received signal strength and can cause variations in the received Signal-to-Interference ratio (SIR), a new DPC scheme, which can estimate the slowly varying channel uncertainty, is proposed so that a target SIR at the receiver can be maintained. Further, the standard assumption of a constant interference during a link's power update used in other works in the literature is relaxed. A CDMA-based cellular network …

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Test 1877: Challenger Mt 655b Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1877: Challenger Mt 655b Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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Test 1891: Kubota L5030 Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1891: Kubota L5030 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

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