%0 Conference Paper
%B Computer Vision, 2005. ICCV 2005. Tenth IEEE International Conference on
%D 2005
%T An algebraic approach to surface reconstruction from gradient fields
%A Agrawal,A.
%A Chellapa, Rama
%A Raskar, R.
%K algebra;
%K algebraic
%K approach;
%K Computer
%K confinement;
%K discrete
%K domain
%K error
%K field;
%K from
%K gradient
%K graph
%K image
%K integrability;
%K linear
%K local
%K methods;
%K photometric
%K reconstruction;
%K shading;
%K SHAPE
%K stereo;
%K surface
%K system;
%K theory;
%K vision;
%X Several important problems in computer vision such as shape from shading (SFS) and photometric stereo (PS) require reconstructing a surface from an estimated gradient field, which is usually non-integrable, i.e. have non-zero curl. We propose a purely algebraic approach to enforce integrability in discrete domain. We first show that enforcing integrability can be formulated as solving a single linear system Ax =b over the image. In general, this system is under-determined. We show conditions under which the system can be solved and a method to get to those conditions based on graph theory. The proposed approach is non-iterative, has the important property of local error confinement and can be applied to several problems. Results on SFS and PS demonstrate the applicability of our method.
%B Computer Vision, 2005. ICCV 2005. Tenth IEEE International Conference on
%V 1
%P 174 - 181 Vol. 1 - 174 - 181 Vol. 1
%8 2005/10//
%G eng
%R 10.1109/ICCV.2005.31
%0 Conference Paper
%B Multi-Agent Security and Survivability, 2005 IEEE 2nd Symposium on
%D 2005
%T Approximation results for probabilistic survivability
%A Zhang,Y.
%A Manister,E.
%A Kraus,S.
%A V.S. Subrahmanian
%K application;
%K computing;
%K failure;
%K fault
%K heuristic
%K heuristics
%K industrial
%K model;
%K multi-agent
%K multiagent
%K node
%K probabilistic
%K probability;
%K programming;
%K survivability;
%K system;
%K systems;
%K testing;
%K tolerant
%X As multiagent systems (MASs) are increasingly used in industrial applications, the need to make them more robust and resilient against disruption increases dramatically. The author has developed a probabilistic model (assuming complete ignorance of dependencies between node failures) of survivability based on deploying each agent in a MAS on one or more nodes. Finding a deployment that maximizes survivability is highly intractable for two reasons: firstly, computing the survivability of any deployment is intractable, and secondly, going through an exponential number of deployments to find the best one adds another layer of intractability. In this paper, we study what happens when node failures are independent. We show that computing survivability in this environment is still intractable. We propose various heuristics to compute the survivability of a given deployment. We have implemented and tested all these heuristics. We report on the advantages and disadvantages of different heuristics in different environmental settings.
%B Multi-Agent Security and Survivability, 2005 IEEE 2nd Symposium on
%P 1 - 10
%8 2005/08//
%G eng
%R 10.1109/MASSUR.2005.1507042
%0 Conference Paper
%B Computer Vision and Pattern Recognition, 2005. CVPR 2005. IEEE Computer Society Conference on
%D 2005
%T Kernel-based Bayesian filtering for object tracking
%A Han,Bohyung
%A Zhu,Ying
%A Comaniciu, D.
%A Davis, Larry S.
%K approach;
%K approximation;
%K Bayes
%K Bayesian
%K Carlo
%K density
%K detection;
%K filtering;
%K functions;
%K Gaussian
%K interpolation;
%K kernel-based
%K methods;
%K mixtures;
%K Monte
%K nonGaussian
%K nonlinear
%K object
%K particle
%K probability
%K probability;
%K processes;
%K recognition;
%K sampling
%K sampling;
%K sequences;
%K system;
%K tracking;
%K video
%X Particle filtering provides a general framework for propagating probability density functions in nonlinear and non-Gaussian systems. However, the algorithm is based on a Monte Carlo approach and sampling is a problematic issue, especially for high dimensional problems. This paper presents a new kernel-based Bayesian filtering framework, which adopts an analytic approach to better approximate and propagate density functions. In this framework, the techniques of density interpolation and density approximation are introduced to represent the likelihood and the posterior densities by Gaussian mixtures, where all parameters such as the number of mixands, their weight, mean, and covariance are automatically determined. The proposed analytic approach is shown to perform sampling more efficiently in high dimensional space. We apply our algorithm to real-time tracking problems, and demonstrate its performance on real video sequences as well as synthetic examples.
%B Computer Vision and Pattern Recognition, 2005. CVPR 2005. IEEE Computer Society Conference on
%V 1
%P 227 - 234 vol. 1 - 227 - 234 vol. 1
%8 2005/06//
%G eng
%R 10.1109/CVPR.2005.199
%0 Conference Paper
%B Information Fusion, 2005 8th International Conference on
%D 2005
%T A new approach to image fusion based on cokriging
%A Memarsadeghi,N.
%A Le Moigne,J.
%A Mount, Dave
%A Morisette,J.
%K ALI;
%K analysis;
%K based
%K cokriging;
%K component
%K data;
%K forecasting
%K fusion
%K fusion;
%K geophysical
%K geostatistical
%K Hyperion
%K image
%K Interpolation
%K interpolation;
%K invasive
%K ISFS
%K method;
%K metrics;
%K PCA;
%K principal
%K processing;
%K project;
%K QUALITY
%K quantitative
%K remote
%K remotely
%K sensed
%K sensing;
%K sensor
%K sensors;
%K signal
%K species
%K system;
%K techniques;
%K transforms;
%K wavelet
%K wavelet-based
%X We consider the image fusion problem involving remotely sensed data. We introduce cokriging as a method to perform fusion. We investigate the advantages of fusing Hyperion with ALI. This evaluation is performed by comparing the classification of the fused data with that of input images and by calculating well-chosen quantitative fusion quality metrics. We consider the invasive species forecasting system (ISFS) project as our fusion application. The fusion of ALI with Hyperion data is studied using PCA and wavelet-based fusion. We then propose utilizing a geostatistical based interpolation method called cokriging as a new approach for image fusion.
%B Information Fusion, 2005 8th International Conference on
%V 1
%P 8 pp. - 8 pp.
%8 2005/07//
%G eng
%R 10.1109/ICIF.2005.1591912
%0 Conference Paper
%B Image Processing, 2005. ICIP 2005. IEEE International Conference on
%D 2005
%T Pedestrian classification from moving platforms using cyclic motion pattern
%A Yang Ran
%A Qinfen Zheng
%A Weiss, I.
%A Davis, Larry S.
%A Abd-Almageed, Wael
%A Liang Zhao
%K analysis;
%K angle;
%K body
%K classification;
%K compact
%K cyclic
%K DETECTION
%K detection;
%K digital
%K Feedback
%K Gait
%K human
%K image
%K information;
%K locked
%K loop
%K loop;
%K loops;
%K module;
%K MOTION
%K object
%K oscillations;
%K pattern;
%K pedestrian
%K phase
%K Pixel
%K principle
%K representation;
%K sequence;
%K sequences;
%K SHAPE
%K system;
%X This paper describes an efficient pedestrian detection system for videos acquired from moving platforms. Given a detected and tracked object as a sequence of images within a bounding box, we describe the periodic signature of its motion pattern using a twin-pendulum model. Then a principle gait angle is extracted in every frame providing gait phase information. By estimating the periodicity from the phase data using a digital phase locked loop (dPLL), we quantify the cyclic pattern of the object, which helps us to continuously classify it as a pedestrian. Past approaches have used shape detectors applied to a single image or classifiers based on human body pixel oscillations, but ours is the first to integrate a global cyclic motion model and periodicity analysis. Novel contributions of this paper include: i) development of a compact shape representation of cyclic motion as a signature for a pedestrian, ii) estimation of gait period via a feedback loop module, and iii) implementation of a fast online pedestrian classification system which operates on videos acquired from moving platforms.
%B Image Processing, 2005. ICIP 2005. IEEE International Conference on
%V 2
%P II - 854-7 - II - 854-7
%8 2005/09//
%G eng
%R 10.1109/ICIP.2005.1530190
%0 Conference Paper
%B Advanced Video and Signal Based Surveillance, 2005. AVSS 2005. IEEE Conference on
%D 2005
%T VidMAP: video monitoring of activity with Prolog
%A Shet,V. D
%A Harwood,D.
%A Davis, Larry S.
%K activities
%K algorithms;
%K based
%K Computer
%K computerised
%K engine;
%K higher
%K image
%K level
%K Logic
%K monitoring;
%K multicamera
%K processing;
%K programming;
%K Prolog
%K PROLOG;
%K reasoning
%K recognition;
%K scenario;
%K signal
%K streaming;
%K streams;
%K Surveillance
%K surveillance;
%K system;
%K video
%K VISION
%K vision;
%K visual
%X This paper describes the architecture of a visual surveillance system that combines real time computer vision algorithms with logic programming to represent and recognize activities involving interactions amongst people, packages and the environments through which they move. The low level computer vision algorithms log primitive events of interest as observed facts, while the higher level Prolog based reasoning engine uses these facts in conjunction with predefined rules to recognize various activities in the input video streams. The system is illustrated in action on a multi-camera surveillance scenario that includes both security and safety violations.
%B Advanced Video and Signal Based Surveillance, 2005. AVSS 2005. IEEE Conference on
%P 224 - 229
%8 2005/09//
%G eng
%R 10.1109/AVSS.2005.1577271
%0 Conference Paper
%B Distributed Computing Systems, 2004. Proceedings. 24th International Conference on
%D 2004
%T Adaptive replication in peer-to-peer systems
%A Gopalakrishnan,V.
%A Silaghi,B.
%A Bhattacharjee, Bobby
%A Keleher,P.
%K adaptive
%K allocation;
%K data
%K databases;
%K decentralized
%K delivery
%K distributed
%K LAR
%K low-latency
%K peer-to-peer
%K processing;
%K protocol;
%K replicated
%K replication
%K resource
%K strategies;
%K structured
%K system-neutral
%K system;
%K systems;
%X Peer-to-peer systems can be used to form a low-latency decentralized data delivery system. Structured peer-to-peer systems provide both low latency and excellent load balance with uniform query and data distributions. Under the more common skewed access distributions, however, individual nodes are easily overloaded, resulting in poor global performance and lost messages. This paper describes a lightweight, adaptive, and system-neutral replication protocol, called LAR, that maintains low access latencies and good load balance even under highly skewed demand. We apply LAR to Chord and show that it has lower overhead and better performance than existing replication strategies.
%B Distributed Computing Systems, 2004. Proceedings. 24th International Conference on
%P 360 - 369
%8 2004///
%G eng
%R 10.1109/ICDCS.2004.1281601
%0 Conference Paper
%B Image Processing, 2004. ICIP '04. 2004 International Conference on
%D 2004
%T Facial similarity across age, disguise, illumination and pose
%A Ramanathan,N.
%A Chellapa, Rama
%A Roy Chowdhury, A.K.
%K Aging
%K database
%K databases;
%K disguise;
%K effect;
%K Expression
%K Face
%K half-face;
%K illumination;
%K image
%K lighting;
%K pose
%K recognition
%K recognition;
%K retrieval;
%K system;
%K variation;
%K visual
%X Illumination, pose variations, disguises, aging effects and expression variations are some of the key factors that affect the performance of face recognition systems. Face recognition systems have always been studied from a recognition perspective. Our emphasis is on deriving a measure of similarity between faces. The similarity measure provides insights into the role each of the above mentioned variations play in affecting the performance of face recognition systems. In the process of computing the similarity measure between faces, we suggest a framework to compensate for pose variations and introduce the notion of 'half-faces' to circumvent the problem of non-uniform illumination. We used the similarity measure to retrieve similar faces from a database containing multiple images of individuals. Moreover, we devised experiments to study the effect age plays in affecting facial similarity. In conclusion, the similarity measure helps in studying the significance facial features play in affecting the performance of face recognition systems.
%B Image Processing, 2004. ICIP '04. 2004 International Conference on
%V 3
%P 1999 - 2002 Vol. 3 - 1999 - 2002 Vol. 3
%8 2004/10//
%G eng
%R 10.1109/ICIP.2004.1421474
%0 Journal Article
%J Magnetics, IEEE Transactions on
%D 2004
%T Finite-element computation of nonlinear magnetic diffusion and its effects when coupled to electrical, mechanical, and hydraulic systems
%A Brauer,J.R.
%A Mayergoyz, Issak D
%K actuator;
%K actuators;
%K analysis;
%K axisymmetric
%K B-H
%K coupled
%K currents;
%K curves;
%K cylinders;
%K diffusion
%K diffusion;
%K eddy
%K electrical
%K electrohydraulic
%K electrohydraulics;
%K electromagnetic
%K element
%K equivalent
%K finite
%K finite-element
%K flux;
%K hydraulic
%K magnetic
%K mechanical
%K methods;
%K nonlinear
%K resistor;
%K responses;
%K steel
%K system;
%K systems;
%K times;
%K transducers;
%X Finite elements are used to compute eddy currents and magnetic diffusion times in steel cylinders with nonlinear B–H curves. Computations are made of diffusion times versus current in a typical axisymmetric magnetic actuator, showing good agreement with recently published approximate analytical formulas. The computed nonlinear diffusion times are then used to derive an equivalent resistor that is used in a model of an electrohydraulic system. The diffusion time causes delays in the coupled mechanical and hydraulic responses.
%B Magnetics, IEEE Transactions on
%V 40
%P 537 - 540
%8 2004/03//
%@ 0018-9464
%G eng
%N 2
%R 10.1109/TMAG.2004.824591
%0 Conference Paper
%B Mixed and Augmented Reality, 2004. ISMAR 2004. Third IEEE and ACM International Symposium on
%D 2004
%T Recording and reproducing high order surround auditory scenes for mixed and augmented reality
%A Zhiyun Li
%A Duraiswami, Ramani
%A Davis, Larry S.
%K array;
%K audio
%K auditory
%K augmented
%K Computer
%K graphics;
%K high
%K loudspeaker
%K microphone
%K mixed
%K order
%K processing;
%K reality
%K reality;
%K scene;
%K signal
%K surround
%K system;
%K technology;
%K virtual
%K VISION
%K vision;
%X Virtual reality systems are largely based on computer graphics and vision technologies. However, sound also plays an important role in human's interaction with the surrounding environment, especially for the visually impaired people. In this paper, we develop the theory of recording and reproducing real-world surround auditory scenes in high orders using specially designed microphone and loudspeaker arrays. It is complementary to vision-based technologies in creating mixed and augmented realities. Design examples and simulations are presented.
%B Mixed and Augmented Reality, 2004. ISMAR 2004. Third IEEE and ACM International Symposium on
%P 240 - 249
%8 2004/11//
%G eng
%R 10.1109/ISMAR.2004.51
%0 Conference Paper
%B Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on
%D 2004
%T Role of shape and kinematics in human movement analysis
%A Veeraraghavan,A.
%A Chowdhury, A.R.
%A Chellapa, Rama
%K activity
%K algorithm;
%K algorithms;
%K analysis;
%K autoregressive
%K average
%K based
%K classification;
%K community;
%K Computer
%K definition;
%K dynamical
%K extraction;
%K feature
%K Gait
%K hidden
%K human
%K identification
%K image
%K Kendall
%K linear
%K manifold;
%K Markov
%K modeling;
%K models;
%K MOTION
%K Movement
%K moving
%K processes;
%K recognition
%K sequences;
%K SHAPE
%K spherical
%K system;
%K VISION
%K vision;
%X Human gait and activity analysis from video is presently attracting a lot of attention in the computer vision community. In this paper we analyze the role of two of the most important cues in human motion-shape and kinematics. We present an experimental framework whereby it is possible to evaluate the relative importance of these two cues in computer vision based recognition algorithms. In the process, we propose a new gait recognition algorithm by computing the distance between two sequences of shapes that lie on a spherical manifold. In our experiments, shape is represented using Kendall's definition of shape. Kinematics is represented using a Linear Dynamical system We place particular emphasis on human gait. Our conclusions show that shape plays a role which is more significant than kinematics in current automated gait based human identification algorithms. As a natural extension we study the role of shape and kinematics in activity recognition. Our experiments indicate that we require models that contain both shape and kinematics in order to perform accurate activity classification. These conclusions also allow us to explain the relative performance of many existing methods in computer-based human activity modeling.
%B Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on
%V 1
%P I-730 - I-737 Vol.1 - I-730 - I-737 Vol.1
%8 2004/07/02/june
%G eng
%R 10.1109/CVPR.2004.1315104
%0 Conference Paper
%B Image Processing, 2004. ICIP '04. 2004 International Conference on
%D 2004
%T Security evaluation for communication-friendly encryption of multimedia
%A Mao,Yinian
%A M. Wu
%K access
%K approximation
%K atomic
%K attacks;
%K bitrate
%K coding;
%K communication-friendly
%K communication;
%K control;
%K cryptography;
%K data
%K encryption
%K encryption;
%K generic
%K joint
%K method;
%K metrics;
%K multimedia
%K multimedia-specific
%K overhead;
%K primitives;
%K processing/cryptographic
%K Security
%K security;
%K signal
%K system;
%K Telecommunication
%K video
%X This paper addresses the access control issues unique to multimedia, by using a joint signal processing and cryptographic approach to multimedia encryption. Based on three atomic encryption primitives, we present a systematic study on how to strategically integrate different atomic operations to build a video encryption system. We also propose a set of multimedia-specific security metrics to quantify the security against approximation attacks and to complement the existing notion of generic data security. The resulting system can provide superior performance to both generic encryption and its simple adaptation to video in terms of a joint consideration of security, bitrate overhead, and communication friendliness.
%B Image Processing, 2004. ICIP '04. 2004 International Conference on
%V 1
%P 569 - 572 Vol. 1 - 569 - 572 Vol. 1
%8 2004/10//
%G eng
%R 10.1109/ICIP.2004.1418818
%0 Conference Paper
%B Intelligent Transportation Systems, 2004. Proceedings. The 7th International IEEE Conference on
%D 2004
%T A spherical microphone array system for traffic scene analysis
%A Zhiyun Li
%A Duraiswami, Ramani
%A Grassi,E.
%A Davis, Larry S.
%K -6
%K 3D
%K analysis;
%K array
%K arrays;
%K audio;
%K auditory
%K beamformer;
%K capture;
%K dB;
%K environment;
%K gain;
%K microphone
%K NOISE
%K noise;
%K processing;
%K real
%K robust
%K scene
%K signal
%K spherical
%K system;
%K traffic
%K traffic;
%K virtual
%K white
%K World
%X This paper describes a practical spherical microphone array system for traffic auditory scene capture and analysis. Our system uses 60 microphones positioned on the rigid surface of a sphere. We then propose an optimal design of a robust spherical beamformer with minimum white noise gain (WNG) of -6 dB. We test this system in a real-world traffic environment. Some preliminary simulation and experimental results are presented to demonstrate its performance. This system may also find applications in broader areas such as 3D audio, virtual environment, etc.
%B Intelligent Transportation Systems, 2004. Proceedings. The 7th International IEEE Conference on
%P 338 - 342
%8 2004/10//
%G eng
%R 10.1109/ITSC.2004.1398921
%0 Conference Paper
%B Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on
%D 2004
%T A system identification approach for video-based face recognition
%A Aggarwal,G.
%A Chowdhury, A.K.R.
%A Chellapa, Rama
%K and
%K autoregressive
%K average
%K dynamical
%K Face
%K gallery
%K identification;
%K image
%K linear
%K model;
%K moving
%K processes;
%K processing;
%K recognition;
%K sequences;
%K signal
%K system
%K system;
%K video
%K video-based
%X The paper poses video-to-video face recognition as a dynamical system identification and classification problem. We model a moving face as a linear dynamical system whose appearance changes with pose. An autoregressive and moving average (ARMA) model is used to represent such a system. The choice of ARMA model is based on its ability to take care of the change in appearance while modeling the dynamics of pose, expression etc. Recognition is performed using the concept of sub space angles to compute distances between probe and gallery video sequences. The results obtained are very promising given the extent of pose, expression and illumination variation in the video data used for experiments.
%B Pattern Recognition, 2004. ICPR 2004. Proceedings of the 17th International Conference on
%V 4
%P 175 - 178 Vol.4 - 175 - 178 Vol.4
%8 2004/08//
%G eng
%R 10.1109/ICPR.2004.1333732
%0 Conference Paper
%B Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on
%D 2004
%T View independent human body pose estimation from a single perspective image
%A Parameswaran, V.
%A Chellapa, Rama
%K 3D
%K analysis;
%K biomechanics;
%K body
%K body-centric
%K camera;
%K capture
%K coordinate
%K coordinates;
%K detection;
%K epipolar
%K equation
%K estimation;
%K geometry;
%K human
%K image
%K image;
%K images;
%K model-based
%K models;
%K MOTION
%K object
%K optical
%K perspective
%K physiological
%K polynomial
%K polynomials;
%K pose
%K real
%K single
%K synthetic
%K system;
%K systems;
%K torso
%K tracking;
%K twist;
%K uncalibrated
%X Recovering the 3D coordinates of various joints of the human body from an image is a critical first step for several model-based human tracking and optical motion capture systems. Unlike previous approaches that have used a restrictive camera model or assumed a calibrated camera, our work deals with the general case of a perspective uncalibrated camera and is thus well suited for archived video. The input to the system is an image of the human body and correspondences of several body landmarks, while the output is the set of 3D coordinates of the landmarks in a body-centric coordinate system. Using ideas from 3D model based invariants, we set up a polynomial system of equations in the unknown head pitch, yaw and roll angles. If we are able to make the often-valid assumption that the torso twist is small, there are finite numbers of solutions to the head-orientation that can be computed readily. Once the head orientation is computed, the epipolar geometry of the camera is recovered, leading to solutions to the 3D joint positions. Results are presented on synthetic and real images.
%B Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings of the 2004 IEEE Computer Society Conference on
%V 2
%P II-16 - II-22 Vol.2 - II-16 - II-22 Vol.2
%8 2004/07/02/june
%G eng
%R 10.1109/CVPR.2004.1315139
%0 Conference Paper
%B INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications. IEEE Societies
%D 2003
%T Cooperative peer groups in NICE
%A Lee,S.
%A Sherwood,R.
%A Bhattacharjee, Bobby
%K algorithm;
%K cooperative
%K decentralized
%K distributed
%K identification;
%K individual
%K inference
%K inference;
%K information
%K Internet;
%K malicious
%K manner;
%K mechanisms;
%K networks;
%K NICE
%K node;
%K noncooperative
%K peer-to-peer
%K platform;
%K reputation
%K retrieval;
%K storage;
%K system;
%K trust
%K users
%K users;
%X A distributed scheme for trust inference in peer-to-peer networks is presented. Our work is in context of the NICE system, which is a platform for implementing cooperative applications over the Internet. We describe a technique for efficiently storing user reputation information in a completely decentralized manner, and show how this information can be used to efficiently identify noncooperative users in NICE. We present a simulation based study of our algorithms, in which we show our scheme scales to thousands of users using modest amounts of storage, processing, and bandwidth at any individual node. Lastly, we show that our scheme is robust and can form cooperative groups in systems where the vast majority of users are malicious.
%B INFOCOM 2003. Twenty-Second Annual Joint Conference of the IEEE Computer and Communications. IEEE Societies
%V 2
%P 1272 - 1282 vol.2 - 1272 - 1282 vol.2
%8 2003///
%G eng
%R 10.1109/INFCOM.2003.1208963
%0 Journal Article
%J Computers, IEEE Transactions on
%D 2003
%T Deno: a decentralized, peer-to-peer object-replication system for weakly connected environments
%A Cetintemel,U.
%A Keleher,P. J
%A Bhattacharjee, Bobby
%A Franklin,M.J.
%K actions;
%K connected
%K consistency
%K data
%K data;
%K databases;
%K decentralized
%K Deno;
%K distributed
%K environments;
%K epidemic
%K group
%K levels;
%K Linux;
%K malicious
%K management;
%K membership;
%K network
%K object
%K object-replication
%K of
%K operating
%K peer-to-peer
%K protocols;
%K replicated
%K replication;
%K Security
%K security;
%K synchronisation;
%K system;
%K systems;
%K topology;
%K Unix;
%K voting;
%K weakly
%K weighted
%K Win32;
%X This paper presents the design, implementation, and evaluation of the replication framework of Deno, a decentralized, peer-to-peer object-replication system targeted for weakly connected environments. Deno uses weighted voting for availability and pair-wise, epidemic information flow for flexibility. This combination allows the protocols to operate with less than full connectivity, to easily adapt to changes in group membership, and to make few assumptions about the underlying network topology. We present two versions of Deno's protocol that differ in the consistency levels they support. We also propose security extensions to handle a class of malicious actions that involve misrepresentation of protocol information. Deno has been implemented and runs on top of Linux and Win32 platforms. We use the Deno prototype to characterize the performance of the Deno protocols and extensions. Our study reveals several interesting results that provide fundamental insight into the benefits of decentralization and the mechanics of epidemic protocols.
%B Computers, IEEE Transactions on
%V 52
%P 943 - 959
%8 2003/07//
%@ 0018-9340
%G eng
%N 7
%R 10.1109/TC.2003.1214342
%0 Journal Article
%J Magnetics, IEEE Transactions on
%D 2003
%T Geometrical analysis of precessional switching and relaxation in uniformly magnetized bodies
%A Bertotti,G.
%A Mayergoyz, Issak D
%A Serpico,C.
%A d'Aquino,M.
%K analysis;
%K attraction;
%K basins
%K bodies;
%K dynamical
%K dynamics;
%K entanglement;
%K equation;
%K film;
%K films;
%K geometrical
%K integrals
%K Landau-Lifshitz-Gilbert
%K magnetic
%K magnetisation
%K magnetization
%K magnetized
%K motion;
%K of
%K particle;
%K particles;
%K phase
%K portrait;
%K precessional
%K relaxation;
%K reversal;
%K riddled
%K separatrices;
%K single-domain
%K spin
%K switching;
%K system;
%K thin
%K uniformly
%X Precessional switching and relaxation in a single-domain particle or film is studied by using the Landau-Lifshitz-Gilbert equation. The analysis of the switching process is based on the explicit knowledge of two integrals of motion for the magnetization dynamics in the conservative case. The knowledge of these integrals of motions enables one to carry out the geometrical analysis of the system and give the complete phase portrait. The relaxation process which occurs after the magnetization is reversed is analyzed by using geometrical methods and it is showed that the dynamical system exhibits entanglement of separatrices and riddled basins of attraction.
%B Magnetics, IEEE Transactions on
%V 39
%P 2501 - 2503
%8 2003/09//
%@ 0018-9464
%G eng
%N 5
%R 10.1109/TMAG.2003.816453
%0 Conference Paper
%B Proceedings. IEEE Conference on Advanced Video and Signal Based Surveillance, 2003.
%D 2003
%T Scalable image-based multi-camera visual surveillance system
%A Lim,Ser-Nam
%A Davis, Larry S.
%A Elgammal,A.
%K ACQUISITION
%K algorithm;
%K camera;
%K constraints;
%K feature
%K hidden
%K image-based
%K MATCHING
%K maximum
%K multi-camera
%K occlusion
%K pan-tilt-zoom
%K PLAN
%K prediction;
%K processing;
%K removal;
%K scalable
%K scheduling;
%K signal
%K Surveillance
%K surveillance;
%K system;
%K task
%K video
%K view;
%K visibility
%K visual
%K weight
%X We describe the design of a scalable and wide coverage visual surveillance system. Scalability (the ability to add and remove cameras easily during system operation with minimal overhead and system degradation) is achieved by utilizing only image-based information for camera control. We show that when a pan-tilt-zoom camera pans and tilts, a given image point moves in a circular and a linear trajectory, respectively. We create a scene model using a plan view of the scene. The scene model makes it easy for us to handle occlusion prediction and schedule video acquisition tasks subject to visibility constraints. We describe a maximum weight matching algorithm to assign cameras to tasks that meet the visibility constraints. The system is illustrated both through simulations and real video from a 6-camera configuration.
%B Proceedings. IEEE Conference on Advanced Video and Signal Based Surveillance, 2003.
%P 205 - 212
%8 2003/07//
%G eng
%R 10.1109/AVSS.2003.1217923
%0 Journal Article
%J Software Engineering, IEEE Transactions on
%D 2003
%T User interface evaluation and empirically-based evolution of a prototype experience management tool
%A Seaman,C.B
%A Mendonca,M.G.
%A Basili, Victor R.
%A Kim,Y. M
%K data
%K development;
%K empirical
%K EMS;
%K engineering;
%K evaluation;
%K experience
%K experience;
%K Factory;
%K interface
%K interfaces;
%K knowledge
%K management
%K management;
%K model;
%K models;
%K organization
%K performance
%K prototype
%K Q-Labs
%K re-engineering;
%K reusability;
%K reuse;
%K software
%K system;
%K systems
%K tool;
%K user
%X Experience management refers to the capture, structuring, analysis, synthesis, and reuse of an organization's experience in the form of documents, plans, templates, processes, data, etc. The problem of managing experience effectively is not unique to software development, but the field of software engineering has had a high-level approach to this problem for some time. The Experience Factory is an organizational infrastructure whose goal is to produce, store, and reuse experiences gained in a software development organization. This paper describes The Q-Labs Experience Management System (Q-Labs EMS), which is based on the Experience Factory concept and was developed for use in a multinational software engineering consultancy. A critical aspect of the Q-Labs EMS project is its emphasis on empirical evaluation as a major driver of its development and evolution. The initial prototype requirements were grounded in the organizational needs and vision of Q-Labs, as were the goals and evaluation criteria later used to evaluate the prototype. However, the Q-Labs EMS architecture, data model, and user interface were designed to evolve, based on evolving user needs. This paper describes this approach, including the evaluation that was conducted of the initial prototype and its implications for the further development of systems to support software experience management.
%B Software Engineering, IEEE Transactions on
%V 29
%P 838 - 850
%8 2003/09//
%@ 0098-5589
%G eng
%N 9
%R 10.1109/TSE.2003.1232288
%0 Conference Paper
%B Motion and Video Computing, 2002. Proceedings. Workshop on
%D 2002
%T A hierarchical approach for obtaining structure from two-frame optical flow
%A Liu,Haiying
%A Chellapa, Rama
%A Rosenfeld, A.
%K algorithm;
%K aliasing;
%K analysis;
%K computer-rendered
%K depth
%K depth;
%K error
%K estimation;
%K extraction;
%K Face
%K feature
%K flow;
%K gesture
%K hierarchical
%K image
%K images;
%K inverse
%K iterative
%K methods;
%K MOTION
%K nonlinear
%K optical
%K parameter
%K processing;
%K real
%K recognition;
%K sequences;
%K signal
%K structure-from-motion;
%K system;
%K systems;
%K TIME
%K two-frame
%K variation;
%K video
%X A hierarchical iterative algorithm is proposed for extracting structure from two-frame optical flow. The algorithm exploits two facts: one is that in many applications, such as face and gesture recognition, the depth variation of the visible surface of an object in a scene is small compared to the distance between the optical center and the object; the other is that the time aliasing problem is alleviated at the coarse level for any two-frame optical flow estimate so that the estimate tends to be more accurate. A hierarchical representation for the relationship between the optical flow, depth, and the motion parameters is derived, and the resulting non-linear system is iteratively solved through two linear subsystems. At the coarsest level, the surface of the object tends to be flat, so that the inverse depth tends to be a constant, which is used as the initial depth map. Inverse depth and motion parameters are estimated by the two linear subsystems at each level and the results are propagated to finer levels. Error analysis and experiments using both computer-rendered images and real images demonstrate the correctness and effectiveness of our algorithm.
%B Motion and Video Computing, 2002. Proceedings. Workshop on
%P 214 - 219
%8 2002/12//
%G eng
%R 10.1109/MOTION.2002.1182239
%0 Conference Paper
%B Pattern Recognition, 2002. Proceedings. 16th International Conference on
%D 2002
%T Performance evaluation of object detection algorithms
%A Mariano,V.Y.
%A Min,Junghye
%A Park,Jin-Hyeong
%A Kasturi,R.
%A Mihalcik,D.
%A Huiping Li
%A David Doermann
%A Drayer,T.
%K algorithms;
%K common
%K data
%K DETECTION
%K detection;
%K Evaluation
%K evaluation;
%K image
%K object
%K performance
%K recognition;
%K resource
%K set;
%K system;
%K text-detection
%K video
%X The continuous development of object detection algorithms is ushering in the need for evaluation tools to quantify algorithm performance. In this paper a set of seven metrics are proposed for quantifying different aspects of a detection algorithm's performance. The strengths and weaknesses of these metrics are described. They are implemented in the Video Performance Evaluation Resource (ViPER) system and will be used to evaluate algorithms for detecting text, faces, moving people and vehicles. Results for running two previous text-detection algorithms on a common data set are presented.
%B Pattern Recognition, 2002. Proceedings. 16th International Conference on
%V 3
%P 965 - 969 vol.3 - 965 - 969 vol.3
%8 2002///
%G eng
%R 10.1109/ICPR.2002.1048198
%0 Journal Article
%J Magnetics, IEEE Transactions on
%D 2002
%T Perturbation technique for LLG dynamics in uniformly magnetized bodies subject to RF fields
%A Bertotti,G.
%A Mayergoyz, Issak D
%A Serpico,C.
%K analytical
%K anisotropy
%K anisotropy;
%K applied
%K bodies;
%K circularly
%K component;
%K constant-in-time
%K constant;
%K damping
%K demagnetisation;
%K demagnetizing
%K differential
%K dynamics;
%K effective
%K elliptically
%K equation;
%K equations;
%K exactly
%K factors;
%K field;
%K film;
%K films;
%K Frequency
%K gyromagnetic
%K harmonic;
%K higher
%K Landau-Lifshitz-Gilbert
%K large
%K linear
%K magnetic
%K magnetisation;
%K magnetization
%K magnetization;
%K magnetized
%K modes;
%K MOTION
%K order
%K partial
%K particle;
%K particles;
%K perturbation
%K polarized
%K radio
%K ratio;
%K RF
%K saturation
%K solution;
%K solvable
%K system;
%K technique;
%K techniques;
%K thin
%K time-harmonic
%K uniaxial
%K uniformly
%X The problem of magnetization dynamics of a uniformly magnetized uniaxial particle or film, under elliptically polarized applied field, is considered. In the special case of circularly polarized applied field and particles (films) with a symmetry axis, pure time-harmonic magnetization modes exist that can be computed analytically. Deviations from these highly symmetric conditions are treated as perturbation of the symmetric case. The perturbation technique leads to the exactly solvable system of linear differential equations for the perturbations which enables one to compute higher order magnetization harmonic. The analytical solutions are obtained and then compared with numerical results.
%B Magnetics, IEEE Transactions on
%V 38
%P 2403 - 2405
%8 2002/09//
%@ 0018-9464
%G eng
%N 5
%R 10.1109/TMAG.2002.803596
%0 Conference Paper
%B Image Processing. 2002. Proceedings. 2002 International Conference on
%D 2002
%T A recognition algorithm for Chinese characters in diverse fonts
%A Wu,Xianli
%A M. Wu
%K algorithm;
%K central
%K character
%K Chinese
%K contributions;
%K direction
%K discriminator;
%K diverse
%K fonts;
%K image
%K interfaces;
%K LANGUAGE
%K MATCHING
%K matching;
%K multi-dictionary
%K natural
%K OCR
%K optical
%K peripheral
%K recognition
%K recognition;
%K sets;
%K software
%K system;
%X The paper proposes an algorithm for recognizing Chinese characters in many diverse fonts including Song, Fang, Kai, Hei, Yuan, Lishu, Weibei and Xingkai. The algorithm is based on features derived from peripheral direction contributions and utilizes a set of dictionaries. A 3-level matching is first performed with respect to each dictionary. The distance measures associated with these matches are then fed into a central discriminator to output the final recognition result. We propose a new multi-dictionary matching algorithm for use in the central discriminator that utilizes estimated information of neighborhood fonts. Experiments have been performed on a practical OCR software system whose recognition kernel is based on the proposed algorithm. Fast and accurate recognition has been accomplished both in title recognition, involving all of the 8 fonts, and in main-body recognition, that usually involves only the first 4 most commonly used fonts.
%B Image Processing. 2002. Proceedings. 2002 International Conference on
%V 3
%P 981 - 984 vol.3 - 981 - 984 vol.3
%8 2002/06//
%G eng
%R 10.1109/ICIP.2002.1039139