Computer Engineering Commons^™

Identification Of Influential Social Networkers, Magdalini Eirinaki, S. P. Singh Monga, S. Sundaram

Faculty Publications

Online social networking is deeply interleaved in today's lifestyle. People come together and build communities to share thoughts, offer suggestions, exchange information, ideas, and opinions. Moreover, social networks often serve as platforms for information dissemination and product placement or promotion through viral marketing. The success rate in this type of marketing could be increased by targeting specific individuals, called 'influential users', having the largest possible reach within an online community. In this paper, we present a method aiming at identifying the influential users within an online social networking application. We introduce ProfileRank, a metric that uses popularity and activity characteristics …

A Relaxed Fusion Of Information From Real And Synthetic Images To Predict Complex Behavior, Damian M. Lyons, D. Paul Benjamin

Faculty Publications

An important component of cognitive robotics is the ability to mentally simulate physical processes and to compare the expected results with the information reported by a robot's sensors. In previous work, we have proposed an approach that integrates a 3D game-engine simulation into the robot control architecture. A key part of that architecture is the Match-Mediated Difference (MMD) operation, an approach to fusing sensory data and synthetic predictions at the image level. The MMD operation insists that simulated and predicted scenes are similar in terms of the appearance of the objects in the scene. This is an overly restrictive constraint …

Worse-Than-Rayleigh Fading: Experimental Results And Theoretical Models, David W. Matolak, Jeff Frolik

Faculty Publications

This article is motivated by the recent recognition that channel fading for new wireless applications is not always well described by traditional models used for mobile communication systems. In particular, fading data collected for vehicleto- vehicle and wireless sensor network applications has motivated new models for conditions in which channel fading statistics can be worse than Rayleigh. We review the use of statistical channel models, describe our example applications, and provide both measured and modeling results for these severe fading conditions.

An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader, Barry E. Mullins, Gilbert L. Peterson, Robert F. Mills

Faculty Publications

This paper presents a Field Programmable Gate Array (FPGA)-based tool designed to process file transfers using the BitTorrent Peer-to-Peer (P2P) protocol and VoIP phone calls made using the Session Initiation Protocol (SIP). The tool searches selected control messages in real time and compares the unique identifier of the shared file or phone number against a list of known contraband files or phone numbers. Results show the FPGA tool processes P2P packets of interest 92% faster than a software-only configuration and is 97.6% accurate at capturing and processing messages at a traffic load of 89.6 Mbps.

Selection And Recognition Of Landmarks Using Terrain Spatiograms, Damian M. Lyons

Faculty Publications

A team of robots working to explore and map an area may need to share information about landmarks so as to register their local maps and to plan effective exploration strategies. In previous papers we have introduced a combined image and spatial representation for landmarks: terrain spatiograms. We have shown that for manually selected views, terrain spatiograms provide an effective, shared representation that allows for occlusion filtering and a combination of multiple views.

In this paper, we present a landmark saliency architecture (LSA) for automatically selecting candidate landmarks. Using a dataset of 21 outdoor stereo images generated by LSA, we …

Sql Querie Recommendations: A Query Fragment-Based Approach, Jayad Akbarnejad, Magdalini Eirinaki, Suju Koshy, Duc On, Neoklis Polyzotis

Faculty Publications

Relational database systems are becoming increasingly popular in the scientific community to support the interactive exploration of large volumes of data. In this scenario, users employ a query interface (typically, a web-based client) to issue a series of SQL queries that aim to analyze the data and mine it for interesting information. First-time users, however, may not have the necessary knowledge to know where to start their exploration. Other times, users may simply overlook queries that retrieve important information. In this work we describe a framework to assist non-expert users by providing personalized query recommendations. The querying behavior of the …

Personal Vs. Social, Magdalini Eirinaki

Faculty Publications

The last few years we witnessed an impressive growth in social networks and in applications that add value to their amassed information. At the same time, the continuing expansion of mobile platforms and applications (e.g. iPhone), combined with the overwhelming supply of information and services, makes effective personalization and context-awareness much required features. One may consider "personal" and "social" data management as comprising two distinct directions with conflicting characteristics. However, it can be argued that they complement each other and that in future applications they will ultimately converge. This "personal vs. social" predicament presents a number of interesting topics that …

5 Ghz Band Vehicle-To-Vehicle Channels: Models For Multiple Values Of Channel Bandwidth, Qiong Wu, David W. Matolak, Indranil Sen

Faculty Publications

In Sen and Matolak's earlier paper, 5-GHz-band vehicle-to-vehicle (V2V) channel models were presented for channel bandwidths of 5 and 10 MHz. In this paper, we provide additional tapped delay line models for bandwidths of 1, 20, 33.33, and 50 MHz based upon the data used in Sen and Matolak's paper. We provide tables of channel parameters for five types of V2V channel classes and also include example tap correlation coefficients. Root-mean-square delay spread values are summarized, as are values of bandwidth for which the channel frequency correlation takes values of 0.7 and 0.5. As with the results from Sen and …

Detection And Filtering Of Landmark Occlusions Using Terrain Spatiograms, Damian M. Lyons

Faculty Publications

A team of robots cooperating to quickly produce a map needs to share landmark information between members so that the local maps can be accurately merged. However, the appearance of landmarks as seen by members of the team can change dramatically due to the phenomenon of occlusion.

We have previously presented an approach to landmark representation using Terrain Spatiograms – an extension to image spatiograms in which the spatial information relates to the scene rather than the image. Because this representation preserves depth structure, it is possible to identify and filter potential occlusions.

We present an approach to identifying and …

A Visual Imagination Approach To Cognitive Robotics, Damian M. Lyons, Sirhan Chaudhry, D. Paul Benjamin

Faculty Publications

No abstract provided.

Integrating Perception And Problem Solving To Predict Complex Object Behaviors, Damian M. Lyons, Sirhan Chaudhry, Marius Agica, John Vincent Monaco

Faculty Publications

One of the objectives of Cognitive Robotics is to construct robot systems that can be directed to achieve realworld goals by high-level directions rather than complex, low-level robot programming. Such a system must have the ability to represent, problem-solve and learn about its environment as well as communicate with other agents. In previous work, we have proposed ADAPT, a Cognitive Architecture that views perception as top-down and goaloriented and part of the problem solving process.

Our approach is linked to a SOAR-based problem-solving and learning framework. In this paper, we present an architecture for the perceptive and world modelling components …

Fpga Acceleration Of The Phylogenetic Likelihood Function For Bayesian Mcmc Inference Methods, Stephanie Zierke, Jason D. Bakos

Faculty Publications

Background
Likelihood (ML)-based phylogenetic inference has become a popular method for estimating the evolutionary relationships among species based on genomic sequence data. This method is used in applications such as RAxML, GARLI, MrBayes, PAML, and PAUP. The Phylogenetic Likelihood Function (PLF) is an important kernel computation for this method. The PLF consists of a loop with no conditional behavior or dependencies between iterations. As such it contains a high potential for exploiting parallelism using micro-architectural techniques. In this paper, we describe a technique for mapping the PLF and supporting logic onto a Field Programmable Gate Array (FPGA)-based co-processor. By leveraging …

Reverberation-Chamber Test Environment For Outdoor Urban Wireless Propagation Studies, Helge Fielitz, Kate A. Remley, Christopher L. Holloway, Qian Zhang, Qiong Wu, David W. Matolak

Faculty Publications

We introduce a test environment to replicate the well-known clustering of reflections in power delay profiles arising from late-time delays and reflections. Urban wireless propagation environments are known to exhibit such clustering. The test setup combines discrete reflections generated by a fading simulator with the continuous distribution of reflections created in a reverberation chamber. We describe measurements made in an urban environment in Denver, CO, that illustrate these multiple distributions of reflections. Our comparison of measurements made in the urban environment to those made in the new test environment shows good agreement.

Synchronizing Real And Predicted Synthetic Video Imagery For Localization Of A Robot To A 3d Environment, Damian M. Lyons, Sirhan Chaudhry, D. Paul Benjamin

Faculty Publications

A mobile robot moving in an environment in which there are other moving objects and active agents, some of which may represent threats and some of which may represent collaborators, needs to be able to reason about the potential future behaviors of those objects and agents. In previous work, we presented an approach to tracking targets with complex behavior, leveraging a 3D simulation engine to generate predicted imagery and comparing that against real imagery. We introduced an approach to compare real and simulated imagery using an affine image transformation that maps the real scene to the synthetic scene in a …

Mining Frequent Generalized Patterns For Web Personalization In The Presence Of Taxonomies, P. Giannikopoulos, I. Varlamis, Magdalini Eirinaki

Faculty Publications

The Web is a continuously evolving environment, since its content is updated on a regular basis. As a result, the traditional usage-based approach to generate recommendations that takes as input the navigation paths recorded on the Web page level, is not as effective. Moreover, most of the content available online is either explicitly or implicitly characterized by a set of categories organized in a taxonomy, allowing the page-level navigation patterns to be generalized to a higher, aggregate level. In this direction, the authors present the Frequent Generalized Pattern (FGP) algorithm. FGP takes as input the transaction data and a hierarchy …

Using Jackknife To Assess The Quality Of Gene Order Phylogenies, Jian Shi, Yiwei Zhang, Haiwei Luo, Jijun Tang

Faculty Publications

Background
In recent years, gene order data has attracted increasing attention from both biologists and computer scientists as a new type of data for phylogenetic analysis. If gene orders are viewed as one character with a large number of states, traditional bootstrap procedures cannot be applied. Researchers began to use a jackknife resampling method to assess the quality of gene order phylogenies.

Results
In this paper, we design and conduct a set of experiments to validate the performance of this jackknife procedure and provide discussions on how to conduct it properly. Our results show that jackknife is very useful to …

High-Performance Heterogeneous Computing With The Convey Hc-1, Jason D. Bakos

Faculty Publications

Unlike other socket-based reconfigurable coprocessors, the Convey HC-1 contains nearly 40 field-programmable gate arrays, scatter-gather memory modules, a high-capacity crossbar switch, and a fully coherent memory system.

Integrated Circuit Implementation For A Gan Hfet Driver Circuit, Bo Wang, Jason D. Bakos, Antonello Monti

Faculty Publications

This paper presents the design and implementation of a new integrated circuit (IC) that is suitable for driving the new generation of high-frequency GaN HFETs. The circuit, based upon a resonant switching transition technique, is first briefly described and then discussed in detail, focusing on the design process practical considerations. A new level-shifter topology, used to generate the zero and negative gate-source voltages required to switch the GaN HFET, is introduced and analyzed. The experimental measurements included in this paper report the results of tests carried out on an IC designed and fabricated as part of the multiproject die in …

Genome3d: A Viewer-Model Framework For Integrating And Visualizing Multi-Scale Epigenomic Information Within A Three-Dimensional Genome, Thomas M. Asbury, Matt Mitman, Jijun Tang, W. Jim Zheng

Faculty Publications

Background
New technologies are enabling the measurement of many types of genomic and epigenomic information at scales ranging from the atomic to nuclear. Much of this new data is increasingly structural in nature, and is often difficult to coordinate with other data sets. There is a legitimate need for integrating and visualizing these disparate data sets to reveal structural relationships not apparent when looking at these data in isolation.

Results
We have applied object-oriented technology to develop a downloadable visualization tool, Genome3D, for integrating and displaying epigenomic data within a prescribed three-dimensional physical model of the human genome. In order …

Incentive Mechanisms In P2p Media Streaming Systems, Xiao Su, Suchreet Dhaliwal

Faculty Publications

This paper highlights the need to curb free-riding in P2P media streaming systems and discusses the mechanisms by which this could be accomplished. Free riding, whereby a peer utilizes network resources, but does not contribute services could have a huge impact on the efficacy of blue streaming systems, leading to scalability issues and service degradation. We discuss why BitTorrent-like tit-for-tat mechanisms cannot be simply tailored and used in streaming. Even though the problem of free riding is more severe in P2P media streaming than in file sharing, the deployed systems still lack incentive schemes. In this paper, we categorize, analyze, …

Structured P2p Technologies For Distributed Command And Control, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

The utility of Peer-to-Peer (P2P) systems extends far beyond traditional file sharing. This paper provides an overview of how P2P systems are capable of providing robust command and control for Distributed Multi-Agent Systems (DMASs). Specifically, this article presents the evolution of P2P architectures to date by discussing supporting technologies and applicability of each generation of P2P systems. It provides a detailed survey of fundamental design approaches found in modern large-scale P2P systems highlighting design considerations for building and deploying scalable P2P applications. The survey includes unstructured P2P systems, content retrieval systems, communications structured P2P systems, flat structured P2P systems and …

Sharing Landmark Information Using Mixture Of Gaussian Terrain Spatiograms, Damian M. Lyons

Faculty Publications

In this paper we evaluate the use of a novel spatial histogram called the terrain spatiogram as a common representation for exchanging landmark information between robots working as a team to map an area. Individual robots use range sensors to provide the spatial dimension of the spatiogram and video for the image dimension. We have previously shown that terrain spatiograms can be shared between robots in a heterogeneous team to recognize landmarks and to fuse observations from multiple sensors or multiple platforms. A terrain spatiogram using a mixture of Gaussians (MOG) model is introduced and a corresponding normalized spatiogram similarity …

Combining Multiple Scoring Systems For Target Tracking Using Rank-Score Characteristics, Damian M. Lyons, D. Frank Hsu

Faculty Publications

Video target tracking is the process of estimating the current state, and predicting the future state of a target from a sequence of video sensor measurements. Multitarget video tracking is complicated by the fact that targets can occlude one another, affecting video feature measurements in a highly non-linear and difficult to model fashion. In this paper, we apply a multisensory fusion approach to the problem of multitarget video tracking with occlusion. The approach is based on a data-driven method (CFA) to selecting the features and fusion operations that improve a performance criterion. Each sensory cue is treated as a scoring …

Phage-Induced Alignment Of Membrane Proteins Enables The Measurement And Structural Analysis Of Residual Dipolar Couplings With Dipolar Waves And Lambda-Maps, Sang Ho Park, Woo Sung Son, Rishi Mukhopadhyay, Homayoun Valafar, Stanley J. Opella

Faculty Publications

At pH > 6 added filamentous bacteriophage fd is compatible with many of the detergents used to solubilize membrane proteins for solution NMR studies of membrane proteins and, therefore, serves as an alignment media. In combination with strained polyacrylamide gel alignment, Dipolar Waves can be used to directly assess the secondary structure and a λ-map extracts the order tensors for de novo structure calculation of membrane proteins without distance restraints.

Gene Order Phylogeny And The Evolution Of Methanogens, Haiwei Luo, Zhiyi Sun, William Arndt, Jian Shi, Robert Friedman, Jijun Tang

Faculty Publications

Methanogens are a phylogenetically diverse group belonging to Euryarchaeota. Previously, phylogenetic approaches using large datasets revealed that methanogens can be grouped into two classes, “Class I” and “Class II”. However, some deep relationships were not resolved. For instance, the monophyly of “Class I” methanogens, which consist of Methanopyrales, Methanobacteriales and Methanococcales, is disputable due to weak statistical support. In this study, we use MSOAR to identify common orthologous genes from eight methanogen species and a Thermococcale species (outgroup), and apply GRAPPA and FastME to compute distance-based gene order phylogeny. The gene order phylogeny supports two classes of methanogens, but it …

Exploiting Matrix Symmetry To Improve Fpgaaccelerated Conjugate Gradient, Jason D. Bakos, Krishna K. Nagar

Faculty Publications

In this paper we describe a new approach for accelerating the Conjugate Gradient (CG) method using an FPGA co-processor. As in previous approaches, our co-processor performs a double-precision sparse matrix-vector multiplication. However, our implementation doubles the amount of computation per unit of input data by exploiting the symmetry of the input matrix and computing the upper and lower triangle of the input matrix in parallel. Using a Virtex-2 Pro 100 FPGA, we have achieved an observed computational throughput of 1155 MFLOPS.

Sharing And Fusing Landmark Information In A Team Of Autonomous Robots, Damian M. Lyons

Faculty Publications

A team of robots working to explore and map a space may need to share information about landmarks so as register local maps and to plan effective exploration strategies. In this paper we investigate the use of spatial histograms (spatiograms) as a common representation for exchanging landmark information between robots. Each robot can use sonar, stereo, laser and image information to identify potential landmarks. The sonar, laser and stereo information provide the spatial dimension of the spatiogram in a landmark-centered coordinate frame while video provides the image information. We call the result a terrain spatiogram. This representation can be shared …

Mobility Handling In Mac For Wireless Ad Hoc Networks, Anjali Raja, Xiao Su

Faculty Publications

Wireless Sensor Networks (WSNs) are becoming popular in a wide variety of applications. In a WSN, sensor nodes can be static or mobile, depending on applications. Handling mobility in a sensor network can pose interesting challenges in sensor protocol design, and special algorithms are needed to adapt to mobility in the network. In this paper, we survey the current state of art in handling mobility in sensor networks. We first study how mobility affects the design of different layers in the sensor network architecture, and then take a closer look at mobility handling in the MAC layer. We also describe …

Locating And Tracking Objects By Efficient Comparison Of Real And Predicted Synthetic Video Imagery, Damian M. Lyons, D. Paul Benjamin

Faculty Publications

A mobile robot moving in an environment in which there are other moving objects and active agents, some of which may represent threats and some of which may represent collaborators, needs to be able to reason about the potential future behaviors of those objects and agents. In this paper we present an approach to tracking targets with complex behavior, leveraging a 3D simulation engine to generate predicted imagery and comparing that against real imagery. We introduce an approach to compare real and simulated imagery and present results using this approach to locate and track objects with complex behaviors. In this …

Query Recommendations For Interactive Database Exploration, Gloria Chatzopoulou, Magdalini Eirinaki, Neoklis Polyzotis

Faculty Publications

Relational database systems are becoming increasingly popular in the scientific community to support the interactive exploration of large volumes of data. In this scenario, users employ a query interface (typically, a web-based client) to issue a series of SQL queries that aim to analyze the data and mine it for interesting information. First-time users, however, may not have the necessary knowledge to know where to start their exploration. Other times, users may simply overlook queries that retrieve important information. To assist users in this context, we draw inspiration from Web recommender systems and propose the use of personalized query recommendations. …