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Full-Text Articles in Engineering

Architecture And Execution Model For A Survivable Workflow Transaction Infrastructure, Haraldur D. Thorvaldsson, Kenneth J. Goldman Dec 2005

Architecture And Execution Model For A Survivable Workflow Transaction Infrastructure, Haraldur D. Thorvaldsson, Kenneth J. Goldman

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We present a novel architecture and execution model for an infrastructure supporting fault-tolerant, long-running distributed applications spanning multiple administrative domains. Components for both transaction processing and persistent state are replicated across multiple servers, en-suring that applications continue to function correctly de-spite arbitrary (Byzantine) failure of a bounded number of servers. We give a formal model of application execution, based on atomic execution steps, linearizability and a sep-aration between data objects and transactions that act on them. The architecture is designed for robust interoperability across domains, in an open and shared Internet computing infrastructure. A notable feature supporting cross-domain applications is …


Roadmap Query For Sensor Network Assisted Navigation In Dynamic Environments, Sangeeta Bhattacharya, Nuzhet Atay, Gazihan Alankus, Chenyang Lu, O. Burchan Bayazit, Gruia-Catalin Roman Nov 2005

Roadmap Query For Sensor Network Assisted Navigation In Dynamic Environments, Sangeeta Bhattacharya, Nuzhet Atay, Gazihan Alankus, Chenyang Lu, O. Burchan Bayazit, Gruia-Catalin Roman

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Autonomous mobile entity navigation through dynamic and unknown environments is an essential part of many mission critical applications like search and rescue and fire fighting. The dynamism of the environment necessitates the mobile entity to constantly maintain a high degree of awareness of the changing environment. This criteria makes it difficult to achieve good navigation performance by using just on-board sensors and existing navigation methods and motivates the use of wireless sensor networks (WSNs) to aid navigation. In this paper, we present a novel approach that integrates a roadmap based navigation algorithm with a novel network query protocol called Roadmap …


Group Scheduling In Selinux To Mitigate Cpu-Focused Denial Of Service Attacks, Armando Migliaccio, Terry Tidwell, Christopher Gill, Tejasvi Aswathanarayana, Douglas Niehaus Nov 2005

Group Scheduling In Selinux To Mitigate Cpu-Focused Denial Of Service Attacks, Armando Migliaccio, Terry Tidwell, Christopher Gill, Tejasvi Aswathanarayana, Douglas Niehaus

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Popular security techniques such as public-private key encryption, firewalls, and role-based access control offer significant protec-tion of system data, but offer only limited protection of the computations using that data from significant interference due to accident or adversarial attack. However, in an increasing number of modern systems, ensuring the reliable execution of system activities is every bit as important as ensuring data security. This paper makes three contributions to the state of the art in protection of the execution of system activities from accidental or adversarial interference. First, we consider the motivating problem of CPU-focused denial of service attacks, and …


Minimum Power Configuration For Wireless Communication In Sensor Networks, Guoliang Xing, Chenyang Lu, Ying Zhang, Qingfeng Huang, Robert Pless Nov 2005

Minimum Power Configuration For Wireless Communication In Sensor Networks, Guoliang Xing, Chenyang Lu, Ying Zhang, Qingfeng Huang, Robert Pless

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This paper proposes the Minimum Power Configuration (MPC) approach to power management in wireless sensor networks. In contrast to earlier research that treats different radio states (transmission/reception/idle) in isolation, MPC integrates them in a joint optimization problem that depends on both the set of active nodes and the transmission power. We propose four approximation algorithms with provable performance bounds and two practical routing protocols. Simulations based on realistic radio models show that the MPC approach can conserve more energy than existing minimum power routing and topology control protocols. Furthermore, it can flexibly adapt to network workload and radio platforms.


End-To-End Scheduling Strategies For Aperiodic Tasks In Middleware, Yuanfang Zhang, Chenyang Lu, Christopher Gill, Patrick Lardieri, Gautum Thaker Nov 2005

End-To-End Scheduling Strategies For Aperiodic Tasks In Middleware, Yuanfang Zhang, Chenyang Lu, Christopher Gill, Patrick Lardieri, Gautum Thaker

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Many mission-critical distributed real-time applicationsmust handle aperiodic tasks with hard end-to-end dead-lines. Existing middleware such as RT-CORBA lacksschedulability analysis and run-time scheduling mecha-nisms that can provide real-time guarantees to aperiodictasks. This paper makes the following contributions to thestate of the art for end-to-end aperiodic scheduling in mid-dleware. First, we compare two approaches to aperiodicscheduling, the deferrable server and the aperiodic utiliza-tion bound, using representative workloads. Numerical re-sults show that the deferrable server analysis is less pes-simistic than the aperiodic utilization bounds when appliedoffline. Second, we propose a practical approach to tuningdeferrable servers for end-to-end tasks. Third, we describedeferrable server mechanisms …


Context Aware Service Oriented Computing In Mobile Ad Hoc Networks, Radu Handorean, Gruia-Catalin Roman, Christopher Gill Nov 2005

Context Aware Service Oriented Computing In Mobile Ad Hoc Networks, Radu Handorean, Gruia-Catalin Roman, Christopher Gill

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These days we witness a major shift towards small, mobile devices, capable of wireless communication. Their communication capabilities enable them to form mobile ad hoc networks and share resources and capabilities. Service Oriented Computing (SOC) is a new emerging paradigm for distributed computing that has evolved from object-oriented and component-oriented computing to enable applications distributed within and across organizational boundaries. Services are autonomous computational elements that can be described, published, discovered, and orchestrated for the purpose of developing applications. The application of the SOC model to mobile devices provides a loosely coupled model for distributed processing in a resource-poor and …


Mobiquery: A Spatiotemporal Query Service For Mobile Users In Sensor Networks, Guoliang Xing, Sangeeta Bhattacharya, Chenyang Lu, Octav Chipara, Chien-Liang Fok, Gruia-Catalin Roman Oct 2005

Mobiquery: A Spatiotemporal Query Service For Mobile Users In Sensor Networks, Guoliang Xing, Sangeeta Bhattacharya, Chenyang Lu, Octav Chipara, Chien-Liang Fok, Gruia-Catalin Roman

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This paper presents MobiQuery, a spatiotemporal query service that allows mobile users to periodically collect sensor data from the physical environment through wireless sensor networks. A salient feature of \MQ is that it can meet stringent spatiotemporal performance constraints, including query latency, data freshness, and changing areas of interest due to user mobility. We present three just-in-time prefetching protocols that enable MobiQuery to achieve desired spatiotemporal performance despite low node duty cycles, while significantly reducing communication overhead. We validate our approach through both theoretical analysis and extensive simulations under realistic settings including varying user movement patterns and location errors.


A Motion Planning Processor On Reconfigurable Hardware, Nuzhet Atay, Burchan Bayazit Sep 2005

A Motion Planning Processor On Reconfigurable Hardware, Nuzhet Atay, Burchan Bayazit

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Motion planning algorithms enable us to find feasible paths for moving objects. These algorithms utilize feasibility checks to differentiate valid paths from invalid ones. Unfortunately, the computationally expensive nature of such checks reduces the effectiveness of motion planning algorithms. However, by using hardware acceleration to speed up the feasibility checks, we can greatly enhance the performance of the motion planning algorithms. Of course, such acceleration is not limited to feasibility checks; other components of motion planning algorithms can also be accelerated using specially designed hardware. A Field Programmable Gate Array (FPGA) is a great platform to support such an acceleration. …


The Open Network Laboratory (A Resource For High Performance Networking Research), John Dehart, Fred Kuhns, Jyoti Parwatikar, Jonathan Turner, Ken Wong Sep 2005

The Open Network Laboratory (A Resource For High Performance Networking Research), John Dehart, Fred Kuhns, Jyoti Parwatikar, Jonathan Turner, Ken Wong

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The Open Network Laboratory (ONL) is a remotely accessible network testbed designed to enable network researchers to conduct experiments using high performance routers and applications. ONL™s Remote Laboratory Interface (RLI) allows users to easily configure a network topology, initialize and modify the routers™ routing tables, packet classification tables and queuing parameters. It also enables users to add software plugins to the embedded processors available at each of the routers™ ports, enabling the introduction of new functionality. The routers provide a large number of built-in counters to track various aspects of system usage, and the RLI software makes these available through …


Cut-And-Solve: A Linear Search Strategy For Combinatorial Optimization Problems, Sharlee Climer, Weixiong Zhang Aug 2005

Cut-And-Solve: A Linear Search Strategy For Combinatorial Optimization Problems, Sharlee Climer, Weixiong Zhang

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Branch-and-bound and branch-and-cut use search trees to identify optimal solutions. In this paper, we introduce a linear search strategy which we refer to as cut-and-solve and prove optimality and completeness for this method. This search is different from traditional tree searching as there is no branching. At each node in the search path, a relaxed problem and a sparse problem are solved and a constraint is added to the relaxed problem. The sparse problems provide incumbent solutions. When the constraining of the relaxed problem becomes tight enough, its solution value becomes no better than the incumbent solution value. At this …


Efficient And Effective Schemes For Streaming Media Delivery, Cheng Huang Aug 2005

Efficient And Effective Schemes For Streaming Media Delivery, Cheng Huang

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The rapid expansion of the Internet and the increasingly wide deployment of wireless networks provide opportunities to deliver streaming media content to users at anywhere, anytime. To ensure good user experience, it is important to battle adversary effects, such as delay, loss and jitter. In this thesis, we first study efficient loss recovery schemes, which require pure XOR operations. In particular, we propose a novel scheme capable of recovering up to 3 packet losses, and it has the lowest complexity among all known schemes. We also propose an efficient algorithm for array codes decoding, which achieves significant throughput gain and …


Spawn: Service Provision In Ad-Hoc Wireless Networks, Radu Handorean, Gruia-Catalin Roman, Rohan Sen, Gregory Hackmann, Christopher Gill Aug 2005

Spawn: Service Provision In Ad-Hoc Wireless Networks, Radu Handorean, Gruia-Catalin Roman, Rohan Sen, Gregory Hackmann, Christopher Gill

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The increasing ubiquity of wireless mobile computing platforms has opened up the potential for unprecedented levels of communication, coordination and collaboration among mobile computing devices, most of which will occur in an ad hoc, on-demand manner. This paper describes SPAWN, a middleware supporting service provision in ad-hoc wireless networks. The aim of SPAWN is to provide the software resources on mobile devices that facilitate electronic collaboration. This is achieved by applying the principles of service oriented computing (SOC), an emerging paradigm that has seen success in wired settings. SPAWN is an adaptation and extension of the Jini model of SOC …


A Collision Detection Chip On Reconfigurable Hardware, Nuzhet Atay, John W. Lockwood, Burchan Bayazit Jul 2005

A Collision Detection Chip On Reconfigurable Hardware, Nuzhet Atay, John W. Lockwood, Burchan Bayazit

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Collision detection algorithms check the intersection between two given surfaces or volumes. They are computationally-intensive and the capabilities of conventional processors limit their performance. Hardware acceleration of these algorithms can greatly benefit the systems that need collision detection to be performed in real-time. A Field Programmable Gate Array (FPGA) is a great platform to achieve such acceleration. An FPGA is a collection of digital gates which can be reprogrammed at run time, i.e., it can be used as a CPU that reconfigures itself for a given task. In this paper, we present an FPGA based collision detection chip. The chip …


Real-Time Power Aware Routing In Wireless Sensor Networks, Octav Chipara, Zhimin He, Guoliang Xing, Qin Chen, Xiaorui Wang, Chenyang Lu, John Stankovic, Tarek Abdelzaher Jul 2005

Real-Time Power Aware Routing In Wireless Sensor Networks, Octav Chipara, Zhimin He, Guoliang Xing, Qin Chen, Xiaorui Wang, Chenyang Lu, John Stankovic, Tarek Abdelzaher

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Many mission-critical wireless sensor network applications must resolve the inherent conflict between the tight resource constraints on each sensor node, particularly in terms of energy, with the need to achieve desired quality of service such as end-to-end real-time performance. To address this challenge we propose the Real-time Power-Aware Routing (RPAR) protocol. RPAR achieves required communication delays at minimum energy cost by dynamically adapting the transmission power and routing decisions based on packet deadlines. RPAR integrates a geographic forwarding policy cognizant of deadlines, power, and link quality with new algorithms for on-demand power adaptation and efficient neighborhood discovery. Simulations based on …


Auto-Pipe: A Pipeline Design And Evaluation System, Mark A. Franklin, John Maschmeyer, Eric Tyson, James Buckley, Patrick Crowley Jun 2005

Auto-Pipe: A Pipeline Design And Evaluation System, Mark A. Franklin, John Maschmeyer, Eric Tyson, James Buckley, Patrick Crowley

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Auto-Pipe is a tool that aids in the design, evaluation, and implementation of pipelined applications that are distributed across a set of heterogeneous devices including multiple processors and FPGAs. It has been developed to meet the needs arising in the domains of communications, computation on large datasets, and real time streaming data applications. In this paper, the Auto-Pipe design flow is introduced and two sample applications, developed for compatibility with the Auto-Pipe system, are presented. The sample applications are the Triple-DES encryption standard and a subset of the signal-processing pipeline for VERITAS, a high-energy gamma-ray astrophysics experiment. These applications are …


Architectures For Rule Processing Intrusion Detection And Prevention Systems, Michael E. Attig May 2005

Architectures For Rule Processing Intrusion Detection And Prevention Systems, Michael E. Attig

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High-performance intrusion detection and prevention systems are needed by network administrators in order to protect Internet systems from attack. Researchers have been working to implement components of intrusion detection and prevention systems for the highly popular Snort system in reconfigurable hardware. While considerable progress has been made in the areas of string matching and header processing, complete systems have not yet been demonstrated that effectively combine all of the functionality necessary to perform intrusion detection and prevention for real network systems. In this thesis, three architectures to perform rule processing, the heart of intrusion detection and prevention, are presented. The …


Improving The Performance Of Internet Data Transport, Anshul Kantawala, Jonathan S. Turner May 2005

Improving The Performance Of Internet Data Transport, Anshul Kantawala, Jonathan S. Turner

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With the explosion of the World Wide Web, the Internet infrastructure faces new challenges in providing high performance for data traffic. First, it must be able to pro-vide a fair-share of congested link bandwidth to every flow. Second, since web traffic is inherently interactive, it must minimize the delay for data transfer. Recent studies have shown that queue management algorithms such as Tail Drop, RED and Blue are deficient in providing high throughput, low delay paths for a data flow. Two major shortcomings of the current algorithms are: they allow TCP flows to get synchronized and thus require large buffers …


Static Determination Of Allocation Rates To Support Real-Time Garbage Collection, Tobias Mann Apr 2005

Static Determination Of Allocation Rates To Support Real-Time Garbage Collection, Tobias Mann

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While it is generally accepted that garbage-collected languages offer advantages over languages in which objects must be explicitly deallocated, real-time developers are leery of the adverse effects a garbage collector might have on real-time performance. Semiautomatic approaches based on regions have been proposed, but incorrect usage could cause unbounded storage leaks or program failure. Moreover, correct usage cannot be guaranteed at compile-time. Recently, real-time garbage collectors have been developed that provide a guaranteed fraction of the CPU to the application, and the correct operation of those collectors has been proven, subject only to the specification of certain statistics related to …


Composable Timed Automata Models For Real-Time Embedded Systems Middleware, Venkita Subramonian, Christopher Gill, Cesar Sanchez, Henny Sipma Apr 2005

Composable Timed Automata Models For Real-Time Embedded Systems Middleware, Venkita Subramonian, Christopher Gill, Cesar Sanchez, Henny Sipma

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Middleware for distributed real-time embedded (DRE) systems has grown more and more complex in recent years, to address functional and temporal requirements of complex real-time applications. While current approaches for modeling middleware have eased the task of assembling, deploying and configuring middleware and applications, a more formal, fundamental and lower-level set of models is needed to be able to uncover subtle safety and timing errors introduced by interference between computations, particularly in the face of alternative concurrency strategies in the middleware layer. In this paper, we examine how formal models of lower-level middleware building blocks provide an appropriate level of …


What A Mesh: Dependent Data Types For Correct Mesh Manipulation Algorithms, Joel R. Brandt Apr 2005

What A Mesh: Dependent Data Types For Correct Mesh Manipulation Algorithms, Joel R. Brandt

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The Edinburgh Logical Framework (LF) has been proposed as a system for expressing inductively defined sets. I will present an inductive definition of the set of manifold meshes in LF. This definition takes into account the topological characteri-zation of meshes, namely their Euler Characteristic. I will then present a set of dependent data types based on this inductive def-inition. These data types are defined in a programming language based on LF. The language’s type checking guarantees that any typeable expression represents a correct manifold mesh. Furthermore, any mesh can be represented using these data types. Hence, the encoding is sound …


Smartacking: Improving Tcp Performance From The Receiving End, Daniel K. Blandford, Sally A. Goldman, Sergey Gorinsky, Yan Zhou, Daniel R. Dooly Jan 2005

Smartacking: Improving Tcp Performance From The Receiving End, Daniel K. Blandford, Sally A. Goldman, Sergey Gorinsky, Yan Zhou, Daniel R. Dooly

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We present smartacking, a technique that improves performance of Transmission Control Protocol (TCP) via adaptive generation of acknowledgments (ACKs) at the receiver. When the bottleneck link is underutilized, the receiver transmits an ACK for each delivered data segment and thereby allows the connection to acquire the available capacity promptly. When the bottleneck link is at its capacity, the smartacking receiver sends ACKs with a lower frequency reducing the control traffic overhead and slowing down the congestion window growth to utilize the network capacity more effectively. To promote quick deployment of the technique, our primary implementation of smartacking modifies only the …