ppxscal/embedding_network huggingface dataset:
Combination of Edge Element and Optical Flow Estimates for 3D-Model-Based Vehicle Tracking in Traffic Image Sequences
Authors: Michael Haag, Hans-Hellmut Nagel
Venue: International Journal of Computer Vision (1999)

A model-based vehicle tracking system for the evaluation of inner-city traffic video sequences has been systematically tested on about 15 minutes of real world video data. Methodological improvements during preparatory test phases affected&mdash;among other changes&mdash;the combination of edge element and optical flow estimates in the measurement process and a more consequent exploitation of background knowledge. The explication of this knowledge in the form of models facilitates the evaluation of video data for different scenes by exchanging the scene-dependent models. An extensive series of experiments with a large test sample demonstrates that the current version of our system appears to have reached a relative optimum: further interactive tuning of tracking parameters does no longer promise to improve the overall system performance significantly. Even the incorporation of further knowledge regarding vehicle and scene geometry or illumination has to cope with an increasing level of interaction between different knowledge sources and system parameters. Our results indicate that model-based tracking of rigid objects in monocular image sequences may have to be reappraised more thoroughly than anticipated during the recent past.
The OASIS multidatabase prototype
Authors: Mark Roantree, John Murphy, Wilhelm Hasselbring
Venue: ACM SIGMOD Record (1999)

The OASIS Prototype is under development at Dublin City University in Ireland. We describe a multi-database architecture which uses the ODMG model as a canonical model and describe an extention for construction of virtual schemas within the multidatabase system. The OMG model is used to provide a standard distribution layer for data from local databases. This takes the form of CORBA objects representing export schemas from separate data sources.
Predictive analysis of a wavefront application using LogGP
Authors: David Sundaram-Stukel, Mary K. Vernon
Venue: ACM SIGPLAN Notices (1999)

This paper develops a highly accurate LogGP model of a complex wavefront application that uses MPI communication on the IBM SP/2. Key features of the model include: (1) elucidation of the principal wavefront synchronization structure, and (2) explicit high-fidelity models of the MPI-send and MPI-receive primitives. The MPI-send/receive models are used to derive L, o, and G from simple two-node micro-benchmarks. Other model parameters are obtained by measuring small application problem sizes on four SP nodes. Results show that the LogGP model predicts, in seconds and with a high degree of accuracy, measured application execution time for large problems running on 128 nodes. Detailed performance projections are provided for very large future processor configurations that are expected to be available to the application developers. These results indicate that scaling beyond one or two thousand nodes yields greatly diminished improvements in execution time, and that synchronization delays are a principal factor limiting the scalability of the application.
Approximate Solution of Markov Renewal Programs with Finite Time Horizon
Authors: Karl Hinderer, Karl-Heinz Waldmann
Venue: SIAM Journal on Control and Optimization (1999)

The present paper investigates the error committed by using an infinite time horizon Markov renewal program as an approximation of the (often more realistic) Markov renewal program with a finite time horizon t0. Under weak assumptions the error is shown to converge to zero exponentially fast when $t_0 \to \infty$. The convergence is based on explicit error bounds. Improved error bounds hold when the (transformed) transition law has a nontrivial stochastic lower bound. Some bounds use the discounted renewal function. For the latter, monotone upper and lower bounds are obtained by an iterative method combined with an extrapolation. Several examples demonstrate the applicability of the results.
The Change-of-Variables Formula Using Matrix Volume
Authors: Adi Ben-Israel
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

The matrix volume is a generalization, to rectangular matrices, of the absolute value of the determinant. In particular, the matrix volume can be used in change-of-variables formulae, instead of the determinant (if the Jacobi matrix of the underlying transformation is rectangular). This result is applicable to integration on surfaces, illustrated here by several examples.
Collaborative Networks Among Female Middle Managers in aHierarchical Organization
Authors: Kristina Westerberg
Venue: Computer Supported Cooperative Work (1999)

I present empirical findings from an observational study of female municipal middle managers who are home help assistants in elder care. The observations showed that the home help assistants&lsquo; sphere of activity was influenced by two distinct patterns: the official line organization and the invisible horizontal social network. I first give a brief description to the immediate background of the present study. Then I describe the line organization and give two empirical examples of information exchange where the practical implication of the line organization at different levels is visible. However, the study also revealed another pattern opposed to the line organization, called the horizontal network. I will give an empirical example of an incident that illustrates how the home help assistants use a social network to solve problems and to make judgments. The study showed that these networks are not persistent &ndash; they are rebuilt depending upon context. Members of the network can be people both within and outside the municipal organization. Decisions and problem solving are thus conducted in a process of interaction and negotiations with other people. The social networks are not visible in the official organizational description. Still they form the foundation for the home help assistants&lsquo; work and influence their ideas of how the work should be conducted. Finally I discuss some implications of the line organization and the social network and the possible consequences when introducing new technology, i.e., computers in work. In this case the computers were planned to support the line organization but not the work practice of social networks.
Low Voltage Micropower Log-Domain Filters
Authors: Ezz I. El-Masry, Jie Wu
Venue: Analog Integrated Circuits and Signal Processing (2000)

A design technique for low-voltage, micropower continuous-time filters implementing CMOS devices operating in weak inversion is presented. The basic building block is the CMOS log-domain integrator. The effects of the MOS device nonidealities on the integrator are investigated and verified by HSPICE simulations. A 5th-order Chebyshev lowpass ladder filter was designed and simulated. The filter operates with low supply voltage of 1.5 V to achieve a cutoff frequency tunable range of 100 Hz&ndash;100 kHz, and it has a power dissipation of 254 nW/pole at the cutoff frequency of 100 kHz. The filter was laid out using the 0.35-&mu;m mixed-mode polycide CMOS technology and occupies a die area of 0.04 mm^2 without the i/o pads
A Posteriori Error Estimation for Stabilized Mixed Approximations of the Stokes Equations
Authors: David Kay, David Silvester
Venue: SIAM Journal on Scientific Computing (1999)

The practical implementation of the lowest-order Pl - P0 (linear velocity, constant pressure) finite element method for the steady-state incompressible (Navier--)Stokes equations is addressed in this work. Three different types of a posteriori error indicator are introduced and each is shown to be equivalent to the discretization error. Our numerical results show that these indicators can be used to drive an adaptive refinement process which is specially tailored to create grids which conform to the requirements of the local stabilization. It is also shown that the indicators provide an effective method for detecting local singularities in the flow solution.
A Multichannel Approach to Fingerprint Classification
Authors: Anil K. Jain, Salil Prabhakar, Lin Hong
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1999)

Fingerprint classification provides an important indexing mechanism in a fingerprint database. An accurate and consistent classification can greatly reduce fingerprint matching time for a large database. We present a fingerprint classification algorithm which is able to achieve an accuracy better than previously reported in the literature. We classify fingerprints into five categories: whorl, right loop, left loop, arch, and tented arch. The algorithm uses a novel representation (FingerCode) and is based on a two-stage classifier to make a classification. It has been tested on 4,000 images in the NIST-4 database. For the five-class problem, a classification accuracy of 90 percent is achieved (with a 1.8 percent rejection during the feature extraction phase). For the four-class problem (arch and tented arch combined into one class), we are able to achieve a classification accuracy of 94.8 percent (with 1.8 percent rejection). By incorporating a reject option at the classifier, the classification accuracy can be increased to 96 percent for the five-class classification task, and to 97.8 percent for the four-class classification task after a total of 32.5 percent of the images are rejected.
On the Finite Volume Element Method for General Self-Adjoint Elliptic Problems
Authors: Huang Jianguo, Xi Shitong
Venue: SIAM Journal on Numerical Analysis (1998)

The finite volume element method (FVE) is a discretization technique for partial differential equations. This paper develops discretization energy error estimates for general self-adjoint elliptic boundary value problems with FVE based on triangulations, on which there exist linear finite element spaces, and a very general type of control volumes (covolumes).The energy error estimates of this paper are also optimal but the restriction conditions for the covolumes given in [R. E. Bank and D. J. Rose, SIAM J. Numer. Anal., 24 (1987), pp. 777--787], [Z. Q. Cai, Numer. Math., 58 (1991), pp. 713--735] are removed. The authors finally provide a counterexample to show that an expected L2-error estimate does not exist in the usual sense. It is conjectured that the optimal order of $\|u-u_h\|_{0,\Omega}$ should be O(h) for the general case.
Infinite parallel job allocation (extended abstract)
Authors: Petra Berenbrink, Artur Czumaj, Tom Friedetzky, Nikita D. Vvedenskaya
Venue: Proceedings of the twelfth annual ACM symposium on Parallel algorithms and architectures (2000)

In recent years, the task of allocating jobs to servers has been studied with the &ldquo;balls and bins&rdquo; abstraction. Results in this area exploit the large decrease in maximum load that can be achieved by allowing each job (ball) a little freedom in choosing its destination server (bin).In this paper we examine an infinite and parallel allocation process (see [ABS98]) which is related to the &ldquo;balls and bins&rdquo; abstraction. The simple process can be used to model many problems arising in applications like load balancing, data accesses for parallel data servers, hashing, and PRAM simulations.Unfortunately, the parallel allocation process behaves in a highly non-uniform manner which makes its analysis challenging. Even the typically simple question of for which arrival rates the process is stable, is highly non-trivial. In order to cope with this non-uniform behavior we introduce a new sequential process and show (via simulations) that the sequential process models the behavior of the parallel one very accurately. We develop a system of ordinary differential equations in order to describe the behavior of our sequential process and present a thorough analysis of the performance this process. For example, we show that the queue length distribution decreases double-exponentially. Finally, we present simulation results indicating that the solutions to the differential equations very well predict the queue length distribution of our sequential process and the largest injection rate for which it is stable. Summarizing, we can conclude that in all the performance characteristics we have measured experimentally, the parallel and the sequential process are closely related. This indicates that the obtained solution of the differential equations and the results presented above are applicable to the parallel process, too.
A Comparison of Measures for Detecting Natural Shapes in Cluttered Backgrounds
Authors: Lance R. Williams, Karvel K. Thornber
Venue: International Journal of Computer Vision (1999)

We propose a new measure of perceptual saliency and quantitatively compare its ability to detect natural shapes in cluttered backgrounds to five previously proposed measures. As defined in the new measure, the saliency of an edge is the fraction of closed random walks which contain that edge. The transition-probability matrix defining the random walk between edges is based on a distribution of natural shapes modeled by a stochastic motion. Each of the saliency measures in our comparison is a function of a set of affinity values assigned to pairs of edges. Although the authors of each measure define the affinity between a pair of edges somewhat differently, all incorporate the Gestalt principles of good-continuation and proximity in some form. In order to make the comparison meaningful, we use a single definition of affinity and focus instead on the performance of the different functions for combining affinity values. The primary performance criterion is accuracy. We compute false-positive rates in classifying edges as signal or noise for a large set of test figures. In almost every case, the new measure significantly outperforms previous measures.
Fast, Reliable Head Tracking under Varying Illumination: An Approach Based on Registration of Texture-Mapped 3D Models
Authors: Marco La Cascia, Stan Sclaroff, Vassilis Athitsos
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

An improved technique for 3D head tracking under varying illumination conditions is proposed. The head is modeled as a texture mapped cylinder. Tracking is formulated as an image registration problem in the cylinder's texture map image. The resulting dynamic texture map provides a stabilized view of the face that can be used as input to many existing 2D techniques for face recognition, facial expressions analysis, lip reading, and eye tracking. To solve the registration problem in the presence of lighting variation and head motion, the residual error of registration is modeled as a linear combination of texture warping templates and orthogonal illumination templates. Fast and stable on-line tracking is achieved via regularized, weighted least-squares minimization of the registration error. The regularization term tends to limit potential ambiguities that arise in the warping and illumination templates. It enables stable tracking over extended sequences. Tracking does not require a precise initial fit of the model; the system is initialized automatically using a simple 2D face detector. The only assumption is that the target is facing the camera in the first frame of the sequence. The formulation is tailored to take advantage of texture mapping hardware available in many workstations, PCs, and game consoles. The nonoptimized implementation runs at about 15 frames per second on a SGI O2 graphic workstation. Extensive experiments evaluating the effectiveness of the formulation are reported. The sensitivity of the technique to illumination, regularization parameters, errors in the initial positioning, and internal camera parameters are analyzed. Examples and applications of tracking are reported.
Robust Stability of Multivariate Polynomials. Part 1: SmallCoefficient Perturbations
Authors: V. L. Kharitonov, J. A. Torres Muñoz
Venue: Multidimensional Systems and Signal Processing (1999)

This paper presents a detailed analysis of some classes of stable multivariate polynomials. The main aim of the analysis is to give conditions under which polynomials preserve stability when they are subjected to small coefficient variations. The maximal class of such polynomials is introduced. Some basic properties of polynomials from this class are obtained.
A New Network Topology with Multiple Meshes
Authors: Debasish Das, Mallika De, Bhabani P. Sinha
Venue: IEEE Transactions on Computers (1999)

This paper introduces a new network topology, called Multi-Mesh (MM), which uses multiple meshes as the basic building blocks interconnected in a suitable manner. The proposed network consists of $n^4$ processors and is 4-regular with a diameter of $2n$. The network also contains a Hamiltonian cycle. Simple routing algorithms for point-to-point communication, one-to-all broadcast, and multicast have been described for this network. It is shown that a simple $n^2\times n^2$ mesh can also be emulated on this network in O(1) time. Several application examples have been discussed for which this network is found to be more efficient with regard to computational time than the corresponding mesh with the same number of processors. As examples, O$(n)$ time algorithms for finding the sum, average, minimum, and maximum of $n^4$ data values, located at $n^4$ different processors have been discussed. Time-efficient implementations of algorithms for solving nontrivial problems, e.g., Lagrange's interpolation, matrix transposition, matrix multiplication, and Discrete Fourier Transform (DFT) computation have also been discussed. The time complexity of Lagrange's interpolation on this network is O$(n)$ for $n^2$ data points compared to O($n^2$) time on mesh of the same size. Matrix transpose requires O$(n^{0.5}$) time for an $n \timesn$ matrix. The time for multiplying two $n\times n$ matrices is O$(n^{0.6})$ with an AT-cost of O$(n^3)$. DFT of $n$ sample points can be computed in O$(n^{0.6})$ time on this network. Papers [6], [7] show that $n^4$ data elements can be sorted on this network in $O(n)$ time.
A stakeholder win&ndash;win approach to software engineering education
Authors: Barry Boehm, Alexander Egyed, Dan Port, Archita Shah, Julie Kwan, Ray Madachy
Venue: Annals of Software Engineering (1999)

We have been applying the stakeholder win&ndash;win approach to software engineering education. The key stakeholders we are trying to simultaneously satisfy are the students&semi; the industry recipients of our graduates&semi; the software engineering community as parties interested in improved practices&semi; and ourselves as instructors and teaching assistants. In order to satisfy the objectives or win conditions of these stakeholders, we have formed a strategic alliance with the USC Libraries to have software engineering student teams work with Library clients to define, develop, and transition USC digital library applications into operational use. This adds another set of key stakeholders: the Library clients of our class projects. This paper summarizes our experience in developing, conducting, and iterating the course. It concludes by evaluating the degree to which we have been able to meet the stakeholder&dash;determined course objectives.
Is computer technology taught upside down?
Authors: S. P. Maj, D. Veal, P. Charlesworth
Venue: ACM SIGCSE Bulletin (2000)

There has been a continuing fragmentation of traditional computer science into other disciplines such as Multimedia, e-commerce, software engineering etc. In this context the standard computer technology curriculum designed for computer science students is in danger of becoming perceived as increasingly irrelevant --- both by students and employers. The authors review expectations of both students and employers, as determined by market analysis, and present the results of implementing one possible solution to providing an introductory computer technology curriculum suitable not only for students from other disciplines but also as a basis for Computer Science majors.
On the Contour of Random Trees
Authors: Bernhard Gittenberger
Venue: SIAM Journal on Discrete Mathematics (1999)

Two stochastic processes describing the contour of simply generated random trees are studied: the contour process as defined by Gutjahr and Pflug [W. Gutjahr and G. Ch. Pflug, Stochastic Process. Appl., 41 (1992), pp. 69--89] and the traverse process constructed of the node heights during pre-order traversal of the tree. Using multivariate generating functions and singularity analysis the weak convergence of the contour process to Brownian excursion is shown and a new proof of the analogous result for the traverse process is obtained.
MagPIe: MPI's collective communication operations for clustered wide area systems
Authors: Thilo Kielmann, Rutger F. H. Hofman, Henri E. Bal, Aske Plaat, Raoul A. F. Bhoedjang
Venue: ACM SIGPLAN Notices (1999)

Writing parallel applications for computational grids is a challenging task. To achieve good performance, algorithms designed for local area networks must be adapted to the differences in link speeds. An important class of algorithms are collective operations, such as broadcast and reduce. We have developed MAGPIE, a library of collective communication operations optimized for wide area systems. MAGPIE's algorithms send the minimal amount of data over the slow wide area links, and only incur a single wide area latency. Using our system, existing MPI applications can be run unmodified on geographically distributed systems. On moderate cluster sizes, using a wide area latency of 10 milliseconds and a bandwidth of 1 MByte/s, MAGPIE executes operations up to 10 times faster than MPICH, a widely used MPI implementation; application kernels improve by up to a factor of 4. Due to the structure of our algorithms, MAGPIE's advantage increases for higher wide area latencies.
Adapting programming languages technologies for finite-state verification
Authors: Matthew B. Dwyer, John Hatcliff
Venue: ACM SIGSOFT Software Engineering Notes (2000)

Program verification and program transformation are two research areas that have different goals. Program verification aims to increase confidence in software through the use of formal methods and systematic testing. Program transformation rearranges the structure of programs to increase their efficiency or to make them more amenable to some other form of processing. Despite being funded under different NSF awards from the Software Engineering and Languages program on the two different areas above the authors are collaborating to apply results from both awards to develop a set of tools, called Bandera, for transforming Java programs into a form that is amenable to verification using existing model checking tools.
How computer architecture trends may affect future distributed systems: from infiniBand clusters to inter-processor speculation (abstract)
Authors: Mark D. Hill
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

The design of distributed systems is and will be altered by the computer architecture innovations enabled by Moore's Law. I will survey some of these issues and how they might affect the design of distributed systems. Topics will include ideas for merging of clusters and large shared-memory multiprocessors, the emerging InfiniBand system area network standard, the effect of simultaneous multithreading, and the potential for softening the memory wall through inter-processor speculation.