ppxscal/embedding_network huggingface dataset:
A Korovkin-Based Approximation of Multilevel Toeplitz Matrices (With Rectangular Unstructured Blocks) via Multilevel Trigonometric Matrix Spaces
Authors: Stefano Serra Capizzano
Venue: SIAM Journal on Numerical Analysis (1999)

In this paper we are concerned with the approximation of multilevel Toeplitz matrices generated by multivariate rectangular matrix-valued continuous (also L2) functions $f: I^p\rightarrow {\cal C}^{s\times t}$, with $I=[-\pi,\pi]$. We first define a class ${\cal A}_T$ of multilevel trigonometric matrix spaces with unstructured $s\times t$ blocks. Second, we introduce a (multi) sequence of linear approximation operators ${\cal P}_n(X)$, $n=(n_1,n_2,\ldots,n_p)$ acting on complex matrices of dimensions $(n_1\cdots n_p s)\times (n_1\cdots n_p t)$, $n_j\in {\cal N}_+$ and giving the minimizer of the distance of X from a fixed representative of ${\cal A}_T$ with regard to the Frobenius norm. Then, by stating and proving new versions of the Korovkin theorem for $f$ ranging in the Banach space $({\bf C}(I^p,{\cal C}^{s\times t}), \|\cdot\|_\infty)$ and by linking these theorems to the operators ${\cal P}_n$, we prove the ``goodness'' of the proposed approximation in terms of the strong and weak equidistribution of the eigenvalues/singular values of $\{A_n(f)\}$ and $\{{\cal P}_n(A_n(f))\}$. The discussed results provide a very uniform tool for treating the preconditioning problem with applications to a wide variety of structures as analyzed in the twin paper [S. Serra Capizzano, { Calcolo, in press].
APPN&mdash;a continuous evolution336764
Authors: Jesper Nilausen
Venue: International Journal of Network Management (1999)

In the previous five articles in this series on managing APPN &lpar;Advanced Peer to Peer Networking&rpar; we have gone through a lot of basics on APPN architecture, its functions and how it all works and can be managed. In this sixth and final article we will take a look at the major developments in APPN now and in the future. Copyright &copy; 1999 John Wiley Sons, Ltd.
Comparative study of page-based and segment-based software DSM through compiler optimization
Authors: Junpei Niwa, Takashi Matsumoto, Kei Hiraki
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

The experimental results clearly show that the performance of ADSM scheme is limited by the communication of unnecessary data, while that of the UDSM scheme is limited by the instrumentation overhead. The UDSM scheme reduces transmission of unnecessary data and automatically prevents the severe false sharing at fetch-on-write, which is the problem in the page-based scheme.
Edge Detection and Ridge Detection with Automatic Scale Selection
Authors: Tony Lindeberg
Venue: International Journal of Computer Vision (1998)

When computing descriptors of image data, the type of information that can be extracted may be strongly dependent on the scales at which the image operators are applied. This article presents a systematic methodology for addressing this problem. A mechanism is presented for automatic selection of scale levels when detecting one-dimensional image features, such as edges and ridges.A novel concept of a scale-space edge is introduced, defined as a connected set of points in scale-space at which: (i) the gradient magnitude assumes a local maximum in the gradient direction, and (ii) a normalized measure of the strength of the edge response is locally maximal over scales. An important consequence of this definition is that it allows the scale levels to vary along the edge. Two specific measures of edge strength are analyzed in detail, the gradient magnitude and a differential expression derived from the third-order derivative in the gradient direction. For a certain way of normalizing these differential descriptors, by expressing them in terms of so-called &gamma;-normalized derivatives, an immediate consequence of this definition is that the edge detector will adapt its scale levels to the local image structure. Specifically, sharp edges will be detected at fine scales so as to reduce the shape distortions due to scale-space smoothing, whereas sufficiently coarse scales will be selected at diffuse edges, such that an edge model is a valid abstraction of the intensity profile across the edge.Since the scale-space edge is defined from the intersection of two zero-crossing surfaces in scale-space, the edges will by definition form closed curves. This simplifies selection of salient edges, and a novel significance measure is proposed, by integrating the edge strength along the edge. Moreover, the scale information associated with each edge provides useful clues to the physical nature of the edge.With just slight modifications, similar ideas can be used for formulating ridge detectors with automatic selection, having the characteristic property that the selected scales on a scale-space ridge instead reflect the width of the ridge.It is shown how the methodology can be implemented in terms of straightforward visual front-end operations, and the validity of the approach is supported by theoretical analysis as well as experiments on real-world and synthetic data.
DLFM: a transactional resource manager
Authors: Hui-I Hsiao, Inderpal Narang
Venue: ACM SIGMOD Record (2000)

The DataLinks technology developed at IBM Almaden Research Center and now available in DB2 UDB 5.2 introduces a new data type called DATALINK for a database to reference and manage files stored external to the database. An external file is put under a database control by &ldquo;linking&rdquo; the file to the database. Control to a file can also be removed by &ldquo;unlinking&rdquo; it. The technology provides transactional semantics with respect to linking or unlinking the file when DATALINK value is stored or updated. Further more, it provides the following set of properties: (1) managing access control to linked files, (2) enforcing referential integrity, such as referenced file cannot be deleted or renamed as long as it is referenced from the RDBMS, and (3) providing coordinated backup and recovery of RDBMS data with the file data. DataLinks File Manager (DLFM) is a key component of the DataLinks technology. DLFM is a sophisticated SQL application with a set of daemon processes residing at a file server node that work cooperatively with the host database server(s) to manage external files. To reduce the number of messages between database server and DLFM, DLFM maintains a set of meta data on the file system and the files that are under database control. One of the major decisions we made was to build DLFM on top of an existing database manager, such as DB2, instead of implementing a proprietary persistent data store. We have mixed feelings about using the RDBMS to build such a resource manager. One of the major challenges is to support transactional semantics for DLFM operations. To do this, we implemented the two-phase commit protocol in DLFM and designed an innovative scheme to enable rolling back transaction update after local database commit. Also a major gotchas is that the RDBMS' cost based optimizer generates the access plan, which does not take into account the locking costs of a concurrent workload. Using the RDBMS as a black box can cause &ldquo;havoc&rdquo; in terms of causing the lock timeouts and deadlocks and reducing the throughput of a concurrent workload. To solve the problem, we came up with a simple but effective way of influencing the optimizer to generate access plans matching the needs of DLFM implementation. Also several precautions had to be taken to ensure that lock escalation did not take place; next key locking was disabled to avoid deadlocks on heavily used indexes and SQL tables; and timeout mechanism was applied to break global deadlocks. We were able to run 100-client workload for 24 hours without much deadlock/timeout problem in system test. This paper describes the motivation for building the DLFM and the lessons that we have learned from this experience.
Near-Optimal Broadcast in All-Port Wormhole-Routed Hypercubes Using Error-Correcting Codes
Authors: Hyosun Ko, Shahram Latifi, Pradip K. Srimani
Venue: IEEE Transactions on Parallel and Distributed Systems (2000)

A new broadcasting method is presented for hypercubes with wormhole routing mechanism. The communication model assumed allows an $n$-dimensional hypercube to have at most $n$ concurrent I/O communications along its ports. It further assumes a distance insensitivity of $(n+1)$ with no intermediate reception capability for the nodes along the communication path. The approach is based on determination of the set of nodes (called stations) in the hypercube such that for any node in the network there is a station at distance of at most 1. Once stations are identified, parallel disjoint paths are formed from the source to all stations. The broadcasting is accomplished first by sending the message to all stations which will in turn inform the rest of the nodes of the message. To establish node-disjoint paths between the source node and all stations, we introduce a new routing strategy. We prove that multicasting can be done in one routing step as long as the number of destination nodes are at most $n$ in an $n$-dimensional hypercube. The number of broadcasting steps using our routing is equal to or smaller than that obtained in an earlier work; this number is optimal for all hypercube dimensions $n \leq 12$, except for $n=10$.
Robust Design of LV/LP Low-Distortion CMOS Rail-to-Rail Input Stages
Authors: Chi-Hung Lin, Mohammed Ismail, Tales Pimenta
Venue: Analog Integrated Circuits and Signal Processing (1999)

Two robust CMOS rail-to-rail OpAmp input stages are presented for low voltage (&le; 3 V) applications. The robust input stages are implemented using two recently reported universal approaches to achieve constant transconductance. Transconductance control circuit is also introduced to compensate for K_{p}, K_{n} mismatch of PMOS and NMOS differential pairs in the input stage. The input stages are designed for operation in the strong inversion and have a rail-to-rail common mode input voltage range. Compared with an OpAmp with simple complementary input pairs, a two stage rail-to-rail OpAmp design example exhibits lower total harmonic distortion (THD) levels over the entire common mode input voltage range.
Mutation-tolerant protein identification by mass-spectrometry
Authors: Pavel A. Pevzner, Vlado Dančík, Chris L. Tang
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

Database search in tandem mass spectrometry is a powerful tool for protein identification. High-throughput spectral acquisition raises the problem of dealing with genetic variation and peptide modifications within a population of related proteins. A method that cross-correlates and clusters related spectra in large collections of uncharacterized spectra (i.e from normal and diseased individuals) would be extremely valuable in functional proteomics. This problem is far from being simple since very similar peptides may have very different spectra. We introduce a new notion of spectral similarity that allows one to identify related spectra even if the corresponding peptides have multiple modifications/mutations. Based on this notion we developed a new algorithm for mutation-tolerant database search as well as a method for cross-correlating related uncharacterized spectra. The paper describes this new approach and its applications in functional proteomics.
A Compression Algorithm for Probability Transition Matrices
Authors: William M. Spears
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

This paper describes a compression algorithm for probability transition matrices. The compressed matrix is itself a probability transition matrix. In general the compression is not error free, but the error appears to be small even for high levels of compression.
TETRA radio performance evaluated via the software package TETRASIM
Authors: Armando Annunziato, Davide Sorbara
Venue: Mobile Networks and Applications (2000)

TETRA (TErrestrial Trunked RAdio) is a digital mobile radio standard for voice and data transmission. It aims at satisfying the growing request of applications and facilities coming from professional users and emergency services. The system has been standardized by ETSI (European Telecommunications Standards Institute) and is provided with an European harmonized frequency band. The first TETRA networks appeared on the market in 1997. This paper reports TETRA radio performance evaluated via a simulation software package, named TETRASIM, entirely developed at CSELT according to TETRA specifications. The simulation results have been obtained for some of the traffic and control channels specified by the standard, in terms of BER (Bit Error Rate) and MER (Message Erasure Rate). As far as the simulated receiver scheme is concerned, the characteristics of the equivalent low-pass filters and the adopted synchronization technique are reported. The simulated demodulator uses a differential detection scheme with soft decision outputs in the case of coded channels. Performance analyses and results comparison are provided by taking into account the effects of signal-to-noise ratio, co-channel interference, adjacent channel interference, propagation models defined in the standard and mobile unit speed. The simulation results reported in this work have been included in the ETR (ETSI Technical Report) &ldquo;TETRA Designers&rdquo; Guide Part 2: Radio and Traffic Performance&rdquo;.
Distribution of Entries in a Substochastic Matrix Having Eigenvalues Near 1
Authors: D. J. Hartfiel
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

This paper gives a quantitative result that if A is a substochastic matrix and has r eigenvalues which are sufficiently close to 1, then A has r disjoint principal submatrices which are nearly stochastic.
Improving and managing multimedia performance over TCP&ndash;IP nets
Authors: Nathan J. Muller
Venue: International Journal of Network Management (1998)

The TCP&ndash;IP-based Internet and, consequently corporate Intranets, were not designed for multimedia traffic. This article discusses the several ways of improving multimedia performance, finding that data compression techniques are no longer the most important factor. &copy; 1998 John Wiley Sons, Ltd.
Nonlinear Filtering and Control of a Switching Diffusion with Small Observation Noise
Authors: Q. Zhang
Venue: SIAM Journal on Control and Optimization (1998)

This paper is concerned with nonlinear filtering and control of a switching diffusion coupled by an unknown Markov chain. Two statistical estimation methods are used to track the unknown Markov chain. Computable approximate filters are obtained based on these methods. The filters are then used to construct controls for the partially observed system. These controls are shown to be asymptotically optimal as the observation noise tends to zero. Finally an example is considered and numerical experiments are reported.
Scaling Simulation of the Fusing-Restricted Reconfigurable Mesh
Authors: José Alberto Fernández-Zepeda, Ramachandran Vaidyanathan, Jerry L. Trahan
Venue: IEEE Transactions on Parallel and Distributed Systems (1998)

This paper deals with the ability of a model to adapt algorithm instances of different sizes to run on a given model size without significant loss of efficiency. The overhead in simulating a step of a large instance of the model on a smaller instance can quantify this ability. A reconfigurable mesh (R-Mesh) can use its bus structure as a computational resource, presenting an obstacle to efficiently scaling down algorithms to run on a smaller R-Mesh. We construct a scaling simulation of a Fusing-Restricted Reconfigurable Mesh (FR-Mesh), a version of the R-Mesh. The overhead of this simulation depends only on the simulating machine size and not on the simulated machine size. Previously, the R-Mesh was not known to admit such a simulation overhead without significantly reducing its computational power. The small overhead holds importance for flexibility in algorithm design and for running algorithms with various input sizes on an available model of given size. The results of this paper extend to a variety of concurrent write rules and also translate to an improved scaling simulation of an unrestricted R-Mesh.
Implications for a gesture design tool
Authors: Allan Christian Long,  Jr., James A. Landay, Lawrence A. Rowe
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Interest in pen-based user interfaces is growing rapidly. One potentially useful feature of pen-based user interfaces is gestures, that is, a mark or stroke that causes a command to execute. Unfortunately, it is difficult to design gestures that are easy 1) for computers to recognize and 2) for humans to learn and remember. To investigate these problems, we built a prototype tool typical fo those used for designing gesture sets. An experiment was then performed to gain insight into the gesture design process and to evaluate this style of tool. The experiment confirmed that gesture design is very difficult and suggested several ways in which current tools can be improved. The most important improvement is to make the tools more active and provide more guidance for designers. This paper describes the gesture design tool, the experiment, and its results.
A Successive Linear Programming Approach for Initialization and Reinitialization after Discontinuities of Differential-Algebraic Equations
Authors: Vipin Gopal, Lorenz T. Biegler
Venue: SIAM Journal on Scientific Computing (1998)

Determination of consistent initial conditions is an important aspect of the solution of differential-algebraic equations (DAEs). Specification of inconsistent initial conditions, even if they are only slightly inconsistent, often leads to a failure in the initialization problem. In this paper, we present a successive linear programming (SLP) approach for the solution of the DAE derivative array equations for the initialization problem. The SLP formulation handles roundoff errors and inconsistent user specifications, among other things, and allows for reliable convergence strategies that incorporate variable bounds and trust region concepts. A new consistent set of initial conditions is obtained by minimizing the deviation of the variable values from the specified ones. For problems with discontinuities caused by a step change in the input functions, a new criterion is presented for identifying the subset of variables which are continuous across the discontinuity. The SLP formulation is then applied to determine a consistent set of initial conditions for further solution of the problem in the domain after the discontinuity. Numerous example problems are solved to illustrate these concepts.
Attractor-repeller approach for global placement
Authors: Hussein Etawil, Shawki Areibi, Anthony Vannelli
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

Traditionally, analytic placement used linear or quadratic wirelength objective functions. Minimizing either formulation attracts cells sharing common signals (nets) together. The result is a placement with a great deal of overlap among the cells. To reduce cell overlap, the methodology iterates between global optimization and repartitioning of the placement area. In this work, we added new attractive and repulsive forces to the traditional formulation so that overlap among cells is diminished without repartitioning the placement area. The superiority of our approach stems from the fact that our new formulations are convex and no hard constraints are required. A preliminary version of the new placement method is tested using a set of MCNC benchmarks1 and, on average, the new method achieved 3.96% and 7.6% reduction in wirelength and CPU time compared to TimberWolf v7.0 in hierarchical mode [10].
Fast Calculation of Multiple Line Integrals
Authors: A. Brandt, J. Dym
Venue: SIAM Journal on Scientific Computing (1999)

A line integral is defined as the integral of two-dimensional data along a (one-dimensional, straight) line of given length and orientation. Line integrals are used in various forms of edge and line detectors in images and in the computation of the Radon transform. We present a recursive algorithm which enables approximation of discretized line integrals at all lengths, orientations, and locations to within a prescribed error bound in at most O(n, log n, log log n) operations, where $n$ is the number of data points. Furthermore, for most applications (in particular, where even small amounts of noise are present in the data) all of these integrals can be computed to the desired accuracy in about 24n log n operations.
Data communications vs. distributed computing (abstract)
Authors: Craig Partridge
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

From my perspective, one of the more distressing aspects of the past fifteen years is the evolution of data communications and distributed computing into distinct and somewhat disconnected disciplines. It is getting to the point where researchers in each discipline often don't really understand what is going on in the other discipline, even though the two disciplines are logically tightly linked to one another. In this talk I'll explore why I think the disconnection occurred (I'll argue it was due to Fear, Uncertainty and Doubt), why I think it matters (we are each consumers of each other's work), and what (if anything) we can do to increase communications (no pun intended!) between the two disciplines. While this may sound like the typical old fuddy-duddy talk, I'm going to give it a very technical spin. I will focus on key technical breakthroughs in data communications and distributed computing and examine how they have either not been communicated or have insufficiently communicated to the other field. My hope is that you'll feel you learned something by listening to me, even if you disagree with the thesis of my talk.
Selective-set-invalidation (SSI) for soft-error-resilient cache architecture
Authors: Seung H. Hwang, Gwan S. Choi
Venue: ACM SIGARCH Computer Architecture News (1999)

This paper proposes a novel cache-memory design for soft-error silence, and verifies the design through a simulation that uses realistic system and software model. The SSI design is a combination of an n-bit error detector and a fast circuit that allows real-time-forced invalidation of corrupted data sets. The current design supports the write through caching policy and will be extended for the write back policy. To verify the effectiveness of the proposed design approach, mixed-mode simulations are conducted that insert soft-errors(bit-flips) into the cache-memory model. The simulation commences while running different class of programs (ALU-intensive and branch-intensive programs) designed to stress several key functions of the target system. System-level failure modes triggered by the soft errors are observed and all inserted errors are recovered by SSI scheme. The performance and layout-area overheads are also quantified. The worst-case performance/time overhead of the SSI scheme is approximately 9% while the lay-out-area overhead is less than 0.5%