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2010

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Articles 1 - 30 of 667

Full-Text Articles in Computer Engineering

Energy Scavenging System For Indoor Wireless Sensor Network, David Andrew Crea Dec 2010

Energy Scavenging System For Indoor Wireless Sensor Network, David Andrew Crea

Theses

As wireless communication evolves wireless sensors have begun to be integrated into society more and more. As these sensors are used to a greater extent newer and better ways to keep them working optimally have begun to surface. One such method aims to further the sensors energy independence on humans. This technique is known as energy scavenging. The logic behind energy scavenging is to allow the device to have its own reliable source of energy that does not require upkeep, has a long life expectancy, and does not completely rely on an internal power source. The aim of this thesis ...


Modeling Next Generation Air Traffic Control System With Petri Net, Hang Wu Dec 2010

Modeling Next Generation Air Traffic Control System With Petri Net, Hang Wu

Theses

The Federal Aviation Administration (FAA) is one of the largest Air Navigation Service Providers, managing air traffic for more than 15% of the world's airspace. Today's Air Traffic Control (ATC) system cannot meet the growth of the air traffic activities, which brings with more unprecedented delays. At the same time, Air Traffic Controllers are facing higher workload than ever before. The FAA has declared that the existing ATC system will transition to a new system known as “Free Flight”. “Free Flight” will change today's ATC system by giving pilots increased flexibility to choose and modify their routes ...


Weaving A Computing Fabric, Michael N. Huhns, Larry M. Stevens, John W. Keele, Jim E. Wray, Warren M. Snelling, Greg P. Harhay, Randy R. Bradley Dec 2010

Weaving A Computing Fabric, Michael N. Huhns, Larry M. Stevens, John W. Keele, Jim E. Wray, Warren M. Snelling, Greg P. Harhay, Randy R. Bradley

Michael N. Huhns

As sources of information relevant to a particular domain proliferate, we need a methodology for locating, aggregating, relating, fusing, reconciling, and presenting information to users. Interoperability thus must occur not only among the information, but also among the different software applications that process it. Given the large number of potential sources and applications, interoperability becomes an extremely large problem for which manual solutions are impractical. A combination of software agents and ontologies can supply the necessary methodology for interoperability.


Mechanisms For Unbounded, Conflict-Robust Hardware Transactional Memory, Colin Blundell Dec 2010

Mechanisms For Unbounded, Conflict-Robust Hardware Transactional Memory, Colin Blundell

Publicly Accessible Penn Dissertations

Conventional lock implementations serialize access to critical sections guarded by the same lock, presenting programmers with a difficult tradeoff between granularity of synchronization and amount of parallelism realized. Recently, researchers have been investigating an emerging synchronization mechanism called transactional memory as an alternative to such conventional lock-based synchronization. Memory transactions have the semantics of executing in isolation from one another while in reality executing speculatively in parallel, aborting when necessary to maintain the appearance of isolation. This combination of coarse-grained isolation and optimistic parallelism has the potential to ease the tradeoff presented by lock-based programming.

This dissertation studies the hardware ...


Regulatory Conformance Checking: Logic And Logical Form, Nikhil Dinesh Dec 2010

Regulatory Conformance Checking: Logic And Logical Form, Nikhil Dinesh

Publicly Accessible Penn Dissertations

We consider the problem of checking whether an organization conforms to a body of regulation. Conformance is studied in a runtime verification setting. The regulation is translated to a logic, from which we synthesize monitors. The monitors are evaluated as the state of an organization evolves over time, raising an alarm if a violation is detected. An important challenge to this approach comes from the fact that regulations are commonly expressed in natural language. The translation to logic is difficult. Our goal is to assist in this translation by: (a) the design of logics that let us formalize regulation one ...


Integrated Freestanding Single-Crystal Silicon Nanowires: Conductivity And Surface Treatment, Chung-Hoon Lee, Clark Ritz, Minghuang Huang, Michael Ziwisky, Robert Blise, Max Lagally Dec 2010

Integrated Freestanding Single-Crystal Silicon Nanowires: Conductivity And Surface Treatment, Chung-Hoon Lee, Clark Ritz, Minghuang Huang, Michael Ziwisky, Robert Blise, Max Lagally

Electrical and Computer Engineering Faculty Research and Publications

Integrated freestanding single-crystal silicon nanowires with typical dimension of 100 nm × 100 nm × 5 µm are fabricated by conventional 1:1 optical lithography and wet chemical silicon etching. The fabrication procedure can lead to wafer-scale integration of silicon nanowires in arrays. The measured electrical transport characteristics of the silicon nanowires covered with/without SiO2 support a model of Fermi level pinning near the conduction band. The I–V curves of the nanowires reveal a current carrier polarity reversal depending on Si–SiO2 and Si–H bonds on the nanowire surfaces


Anonymous Query Processing In Road Networks, Kyriakos Mouratidis, Man Lung Yiu Dec 2010

Anonymous Query Processing In Road Networks, Kyriakos Mouratidis, Man Lung Yiu

Kyriakos MOURATIDIS

The increasing availability of location-aware mobile devices has given rise to a flurry of location-based services (LBSs). Due to the nature of spatial queries, an LBS needs the user position in order to process her requests. On the other hand, revealing exact user locations to a (potentially untrusted) LBS may pinpoint their identities and breach their privacy. To address this issue, spatial anonymity techniques obfuscate user locations, forwarding to the LBS a sufficiently large region instead. Existing methods explicitly target processing in the euclidean space and do not apply when proximity to the users is defined according to network distance ...


On-Line Discovery Of Hot Motion Paths, Dimitris Sacharidis, Kostas Patroumpas, Manolis Terrovitis, Verena Kantere, Michalis Potamias, Kyriakos Mouratidis, Timos Sellis Dec 2010

On-Line Discovery Of Hot Motion Paths, Dimitris Sacharidis, Kostas Patroumpas, Manolis Terrovitis, Verena Kantere, Michalis Potamias, Kyriakos Mouratidis, Timos Sellis

Kyriakos MOURATIDIS

We consider an environment of numerous moving objects, equipped with location-sensing devices and capable of communicating with a central coordinator. In this setting, we investigate the problem of maintaining hot motion paths, i.e., routes frequently followed by multiple objects over the recent past. Motion paths approximate portions of objects' movement within a tolerance margin that depends on the uncertainty inherent in positional measurements. Discovery of hot motion paths is important to applications requiring classification/profiling based on monitored movement patterns, such as targeted advertising, resource allocation, etc. To achieve this goal, we delegate part of the path extraction process ...


Continuous Monitoring Of Spatial Queries In Wireless Broadcast Environments, Kyriakos Mouratidis, Spiridon Bakiras, Dimitris Papadias Dec 2010

Continuous Monitoring Of Spatial Queries In Wireless Broadcast Environments, Kyriakos Mouratidis, Spiridon Bakiras, Dimitris Papadias

Kyriakos MOURATIDIS

Wireless data broadcast is a promising technique for information dissemination that leverages the computational capabilities of the mobile devices in order to enhance the scalability of the system. Under this environment, the data are continuously broadcast by the server, interleaved with some indexing information for query processing. Clients may then tune in the broadcast channel and process their queries locally without contacting the server. Previous work on spatial query processing for wireless broadcast systems has only considered snapshot queries over static data. In this paper, we propose an air indexing framework that 1) outperforms the existing (i.e., snapshot) techniques ...


Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis Dec 2010

Optimal Matching Between Spatial Datasets Under Capacity Constraints, Hou U Leong, Kyriakos Mouratidis, Man Lung Yiu, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of customers (e.g., WiFi receivers) and a set of service providers (e.g., wireless access points), where each provider has a capacity and the quality of service offered to its customers is anti-proportional to their distance. The capacity constrained assignment (CCA) is a matching between the two sets such that (i) each customer is assigned to at most one provider, (ii) every provider serves no more customers than its capacity, (iii) the maximum possible number of customers are served, and (iv) the sum of Euclidean distances within the assigned provider-customer pairs is minimized. Although max-flow algorithms ...


Continuous Spatial Assignment Of Moving Users, Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis Dec 2010

Continuous Spatial Assignment Of Moving Users, Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis

Kyriakos MOURATIDIS

Consider a set of servers and a set of users, where each server has a coverage region (i.e., an area of service) and a capacity (i.e., a maximum number of users it can serve). Our task is to assign every user to one server subject to the coverage and capacity constraints. To offer the highest quality of service, we wish to minimize the average distance between users and their assigned server. This is an instance of a well-studied problem in operations research, termed optimal assignment. Even though there exist several solutions for the static case (where user locations ...


Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis Dec 2010

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis

Kyriakos MOURATIDIS

Shortest path computation is one of the most common queries in location-based services that involve transportation net- works. Motivated by scalability challenges faced in the mo- bile network industry, we propose adopting the wireless broad- cast model for such location-dependent applications. In this model the data are continuously transmitted on the air, while clients listen to the broadcast and process their queries locally. Although spatial problems have been considered in this environment, there exists no study on shortest path queries in road networks. We develop the rst framework to compute shortest paths on the air, and demonstrate the practicality and ...


Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu Dec 2010

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Kyriakos MOURATIDIS

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate ...


The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam Dec 2010

The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. Traditional networked control schemes are designed with one of the nodes in the network acting as a dedicated controller, while the other nodes simply route information to and from the controller and the plant. We introduce the concept of a Wireless Control Network (WCN) where the entire network itself acts as the controller. Specifically, at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire ...


The Wireless Control Network: Monitoring For Malicious Behavior, Shreyas Sundaram, Miroslav Pajic, Christoforos N. Hadjicostis, Rahul Mangharam, George J. Pappas Dec 2010

The Wireless Control Network: Monitoring For Malicious Behavior, Shreyas Sundaram, Miroslav Pajic, Christoforos N. Hadjicostis, Rahul Mangharam, George J. Pappas

Real-Time and Embedded Systems Lab (mLAB)

We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. In a companion paper, we developed a protocol where each node repeatedly transmits a linear combination of the values in its neighborhood. For certain topologies, we showed that these linear combinations can be designed so that the closed loop system is stable (i.e., the wireless network itself acts as a controller for the plant). In this paper, we design a Intrusion Detection System (IDS) for this control scheme, which observes the transmissions of certain nodes in the network and uses that information to ...


Testing Embedded System Applications, Tingting Yu Dec 2010

Testing Embedded System Applications, Tingting Yu

Computer Science and Engineering: Theses, Dissertations, and Student Research

Embedded systems are becoming increasingly ubiquitous, controlling a wide variety of popular and safety-critical devices. Testing is the most commonly used method for validating software systems, and effective testing techniques could be helpful for improving the dependability of these systems. However, there are challenges involved in developing such techniques. Embedded systems consist of layers of software – application layers utilize services provided by underlying system service and hardware support layers. A typical embedded application consists of multiple user tasks. Interactions between application layers and lower layers, and interactions between the various user tasks that are initiated by the application layer, can ...


Learning With Scope, With Application To Information Extraction And Classification, David M. Blei, J. Andrew Bagnell, Andrew K. Mccallum Dec 2010

Learning With Scope, With Application To Information Extraction And Classification, David M. Blei, J. Andrew Bagnell, Andrew K. Mccallum

Andrew McCallum

In probabilistic approaches to classification and information extraction, one typically builds a statistical model of words under the assumption that future data will exhibit the same regularities as the training data. In many data sets, however, there are scope- limited features whose predictive power is only applicable to a certain subset of the data. For example, in information extraction from web pages, word formatting may be indicative of extraction category in different ways on different web pages. The difficulty with using such features is capturing and exploiting the new regularities encountered in previously unseen data. In this paper, we propose ...


Pre-Eruption Pressure, Temperature And Volatile Content Of Rhyolite Magma From The 1650 Ad Eruption Of Kolumbo Submarine Volcano, Greece, K. Cantner, S. Carey, H. Sigurdsson, G. Vougioukalakis, P. Nomikou, C. Roman, K. Bell, M. Alexandri Dec 2010

Pre-Eruption Pressure, Temperature And Volatile Content Of Rhyolite Magma From The 1650 Ad Eruption Of Kolumbo Submarine Volcano, Greece, K. Cantner, S. Carey, H. Sigurdsson, G. Vougioukalakis, P. Nomikou, C. Roman, K. Bell, M. Alexandri

Christopher N. Roman

Biotite-bearing, crystal-poor rhyolite magma was the predominant magma type discharged during the 1650 AD explosive eruption of Kolumbo submarine volcano, Greece. The eruption produced thick sequences of pumice deposits (~100 m) in the upper crater walls of the volcano, but also led to the formation of extensive pumice rafts that were dispersed throughout the southern Aegean Sea, and subaerial tephra fallout as far east as Turkey. Preliminary estimates of pre-eruption volatile contents have been determined using the volatile-by-difference method on plagioclase-hosted melt inclusions and yield an average value of 6.0 wt.%. This corresponds to a pre-eruption storage pressure of ...


Adaptive Checkpointing For Master-Worker Style Parallelism (Extended Abstract), Gene D. Cooperman, Jason Ansel, Xiaoqin Ma Dec 2010

Adaptive Checkpointing For Master-Worker Style Parallelism (Extended Abstract), Gene D. Cooperman, Jason Ansel, Xiaoqin Ma

Gene D. Cooperman

No abstract provided.


Dmtcp: Transparent Checkpointing For Cluster Computations And The Desktop, Jason Ansel, Kapil Arya, Gene D. Cooperman Dec 2010

Dmtcp: Transparent Checkpointing For Cluster Computations And The Desktop, Jason Ansel, Kapil Arya, Gene D. Cooperman

Gene D. Cooperman

DMTCP (Distributed MultiThreaded CheckPointing) is a transparent user-level checkpointing package for distributed applications. Checkpointing and restart is demonstrated for a wide range of over 20 well known applications, including MATLAB, Python, TightVNC, MPICH2, OpenMPI, and runCMS. RunCMS runs as a 680 MB image in memory that includes 540 dynamic libraries, and is used for the CMS experiment of the Large Hadron Collider at CERN. DMTCP transparently checkpoints general cluster computations consisting of many nodes, processes, and threads; as well as typical desktop applications. On 128 distributed cores (32 nodes), checkpoint and restart times are typically 2 seconds, with negligible run-time ...


Network Security Toolkit Including Heuristic Solutions For Trust System Placement And Network Obfuscation, Gabriel H. Greve Dec 2010

Network Security Toolkit Including Heuristic Solutions For Trust System Placement And Network Obfuscation, Gabriel H. Greve

Theses and Dissertations

For Part I, a supervisory control and data acquisition (SCADA) network consists of a group stations and substations in a portion of the power grid. The use of Internet technology in SCADA communications as well as other factors has caused vulnerabilities. One idea to help mitigate this risk is to strategically place trust nodes to compartmentalize and secure the SCADA systems without disturbing its finely honed processes. The trust nodes combine firewall and intrusion detection technology to provide more secure communication. An optimal solution to this problem has already been developed using a mixed-integer linear programming model. Because the problem ...


Cloud Computing: Strategies For Cloud Computing Adoption, Faith J. Shimba Dec 2010

Cloud Computing: Strategies For Cloud Computing Adoption, Faith J. Shimba

Faith Joel Shimba

The advent of cloud computing in recent years has sparked an interest from different IT stakeholders. This is a result of the new economic model for the IT department that cloud computing promises. The model promises to remove the need for heavy investment for limited IT resources towards renting IT resources and paying based on usage. Although, the adoption of cloud computing promises various benefits to organizations, a successful adoption requires an understanding of different dynamics and expertise in diverse domains. Currently there are inadequate guidelines for adoption and this book proposes a roadmap for cloud computing adoption called ROCCA ...


A Comprehensive Analysis Of Lte Physical Layer, Fahimeh Rezaei Dec 2010

A Comprehensive Analysis Of Lte Physical Layer, Fahimeh Rezaei

Theses, Dissertations, & Student Research in Computer Electronics & Engineering

The 3rd Generation Partnership Project (3GPP) introduced Long Term Evolution (LTE) as the 3rd generation of mobile communication standards. LTE Release 8 describes a mobile communication standard which supports up to 300 Mbps of data transmission in downlink using the OFDM scheme as well as up to 75 Mbps throughput for uplink using the SC-FDMA modulation. In this thesis, an in-depth study of LTE performance based on Release 8 is conducted for uplink and downlink under different scenarios. The main objective of this study is to investigate a comprehensive analysis of physical layer throughput of LTE Release8 based on standard ...


Cross-Layer Optimized Wireless Multimedia Networking, Dalei Wu Dec 2010

Cross-Layer Optimized Wireless Multimedia Networking, Dalei Wu

Theses, Dissertations, & Student Research in Computer Electronics & Engineering

Multimedia communications, especially real-time video communications, is expected to be the major application of the next-generation wireless networks. However, bringing delay-sensitive and loss-tolerant multimedia services based on the current wireless Internet is a very challenging task. In this dissertation, we address cross-layer optimized wireless multimedia networking from both theoretical and practical perspectives. In the first part of the dissertation, we propose cross-layer optimization frameworks for real-time video communications over wireless networks, where the expected received video quality is adopted as the objective function. With the user-centric objective function, we first study content-aware video communications in single-hop wireless networks by exploring ...


The Changing Patterns Of Internet Usage, Christopher S. Yoo Dec 2010

The Changing Patterns Of Internet Usage, Christopher S. Yoo

Federal Communications Law Journal

Symposium: Essays from Time Warner Cable's Research Program on Digital Communications.


The Challenge Of Increasing Broadband Capacity, Dale N. Hatfield Dec 2010

The Challenge Of Increasing Broadband Capacity, Dale N. Hatfield

Federal Communications Law Journal

Symposium: Essays from Time Warner Cable's Research Program on Digital Communications.


How To Bargain: An Interval Approach, Vladik Kreinovich, Hung T. Nguyen, Songsak Sriboonchitta Dec 2010

From Program Synthesis To Optimal Program Synthesis, Joaquin Reyna Dec 2010

Fundamental Physical Equations Can Be Derived By Applying Fuzzy Methodology To Informal Physical Ideas, Eric Gutierrez, Vladik Kreinovich Dec 2010

How To Tell When A Product Of Two Partially Ordered Spaces Has A Certain Property: General Results With Application To Fuzzy Logic, Francisco Zapata, Olga Kosheleva, Karen Villaverde Dec 2010