ppxscal/embedding_network huggingface dataset:
Rule Discovery in Telecommunication AlarmData
Authors: Mika Klemettinen, Heikki Mannila, Hannu Toivonen
Venue: Journal of Network and Systems Management (1999)

Fault management is an important but difficult area of telecommunication network management: networks produce large amounts of alarm information which must be analyzed and interpreted before faults can be located. So called alarm correlation is a central technique in fault identification. While the use of alarm correlation systems is quite popular and methods for expressing the correlations are maturing, acquiring all the knowledge necessary for constructing an alarm correlation system for a network and its elements is difficult. We describe a novel partial solution to the task of knowledge acquisition for correlation systems. We present a method and a tool for the discovery of recurrent patterns of alarms in databases; these patterns, episode rules, can be used in the construction of real-time alarm correlation systems. We also present tools with which network management experts can browse the large amounts of rules produced. The construction of correlation systems becomes easier with these tools, as the episode rules provide a wealth of statistical information about recurrent phenomena in the alarm stream. This methodology has been implemented in a research system called TASA, which is used by several telecommunication operators. We briefly discuss experiences in the use of TASA.
On Approximately Counting Colorings of Small Degree Graphs
Authors: Russ Bubley, Martin Dyer, Catherine Greenhill, Mark Jerrum
Venue: SIAM Journal on Computing (1999)

We consider approximate counting of colorings of an n-vertex graph using rapidly mixing Markov chains. It has been shown by Jerrum and by Salas and Sokal that a simple random walk on graph colorings would mix rapidly, provided the number of colors k exceeded the maximum degree $\Delta$ of the graph by a factor of at least 2. We prove that this is not a necessary condition for rapid mixing by considering the simplest case of 5-coloring graphs of maximum degree 3. Our proof involves a computer-assisted proof technique to establish rapid mixing of a new "heat bath" Markov chain on colorings using the method of path coupling. We outline an extension to 7-colorings of triangle-free 4-regular graphs. Since rapid mixing implies approximate counting in polynomial time, we show in contrast that exact counting is unlikely to be possible (in polynomial time). We give a general proof that the problem of exactly counting the number of proper k-colorings of graphs with maximum degree $\Delta$ is $\# P$-complete whenever $k\geq 3$ and $\Delta \geq 3$.
An approach for improving the levels of compaction achieved by vector omission
Authors: Irith Pomeranz, Sudhakar M. Reddy
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

We describe a method referred to as sequence counting to improve on the levels of compaction achievable by vector omission based static compaction procedures. Such procedures are used to reduce the lengths of test sequences for synchronous sequential circuits without reducing the fault coverage. The unique feature of the proposed approach is that test vectors omitted from the test sequence can be reintroduced at a later time. Reintroducing of vectors helps reduce the compacted test sequence length beyond the length that can be achieved if vectors are omitted permanently. Experimental results are presented to demonstrate the levels of compaction achieved by the sequence counting approach.
Parallel Performance Analysis of the Improved Quasi-Minimal Residual Method on Bulk Synchronous Parallel Architectures
Authors: Tianruo Yang, Hai-Xiang Linh
Venue: The Journal of Supercomputing (1999)

For the solutions of unsymmetric linear systems of equations, we have proposed an improved version of the quasi-minimal residual (IQMR) method &lsqb;21&rsqb; by using the Lanczos process as a major component combining elements of numerical stability and parallel algorithm design. For Lanczos process, stability is obtained by a couple two-term procedure that generates Lanczos vectors scaled to unit length. The algorithm is derived such that all inner products and matrix-vector multiplications of a single iteration step are independent and communication time required for inner product can be overlapped efficiently with computation time. In this paper, we use the Bulk Synchronous Parallel (BSP) model to design a fully efficient, scalable and portable parallel IQMR algorithm and to provide accurate performance prediction of the algorithm for a wide range of architectures including the Cray T3D, the Parsytec GC/PowerPlus, and a cluster of workstations connected by an Ethernet. This performance model provides us useful insight in the time complexity of the IQMR method using only a few system dependent parameters based on a simple and accurate cost modeling. The theoretical performance prediction are compared with measured timing results of a numerical application from ocean flow simulation.
A prescriptive semantics of Fortran 95
Authors: N. Reid, J. P. Wray
Venue: ACM SIGPLAN Fortran Forum (1999)

This paper outlines current research into a prescriptive semantics of Fortran 95, as a means of investigating the language's strengths and shortcomings. Additionally, it is intended that this research will provide a foundation for the application of rigor to Fortran programming.
Variance and Covariance Computations for 2-D ARMA Processes
Authors: Jyh-Haur Hwang, Sun-Yuan Tsay, Chyi Hwang
Venue: Multidimensional Systems and Signal Processing (1999)

An algorithm is presented to compute the variance of the output of a two-dimensional (2-D) stable auto-regressive moving-average (ARMA) process driven by a white noise bi-sequence with unity variance. Actually, the algorithm is dedicated to the evaluation of a complex integral of the form I= \frac{1}{(2 \pi i)^2} \oint_{|z_1| =1} \oint_{|z_2| =1} G(z_1, z_2)\linebreak[4] G(z^{-1}_1, z_2^{-1}) \frac{dz_2 dz_1}{z_2 z_1}, where i = \sqrt{-1} and G(z_1, z_2) = B(z_1, z_2) / A(z_1, z_2) is stable (z_1,z_2)-transfer function. Like other existing methods, the proposed algorithm is based on the partial-fraction decomposition G(z_1,z_2) G(z_1^{-1}, z_2^{-1}) \linebreak[4] = X(z_1, z_1) / A(z_1,z_2) + X(z^{-1}_1 , z^{-1}_2) / A(z^{-1}_1, z^{-1}_2). However, the general and systematic partial-fraction decomposition scheme of Gorecki and Popek [1] is extended to determine X(z_1,z_2). The key to the extension is that of bilinearly transforming the discrete (z_1, z_2)-transfer function G(z_1,z_2) into a mixed continuous-discrete (s_1, z_2)-transfer function \hat{G} (s_1, z_2). As a result, the partial-fraction decomposition involves only efficient DFT computations for the inversion of a matrix polynomial, and the value of I is finally determined by the residue method with finding the roots of a 1-D polynomial. The algorithm is very easy to implement and it can be extended to the covariance computation for two 2-D ARMA processes.
Information Systems that Really Support Decision-Making
Authors: Gio Wiederhold
Venue: Journal of Intelligent Information Systems (2000)

Decision makers are expected to make decisions which have a positive effect on the future of their enterprises. We expect that intelligent information systems support their activities. Today, databases and web-based resources, accessed through effective communications, make information about the past rapidly available. To project the future the decision makers either have to use intuition or employ tool for prediction, and initialize such tools with information obtained from an information system to such tools. An effective information system should integrate forecasting the future, and because there choices have been made, such a system must also support the comparative assessment of the effects of alternate decisions. The complexity of an information system handling the past, and multiple futures will be great, and must be modularized with effective interfaces. We recommend the use of an SQL-like interface language to access existing tools to assess the future, as spreadsheets and simulations. Making results of simulations accessible as another contribution to integrated information systems has the potential of greatly augmenting their effectiveness and really support decision-making.
Scale and Translation Invariant Methods for Enhanced Time-FrequencyPattern Recognition
Authors: William J. Williams, Eugene J. Zalubas, Robert M. Nickel, Alfred O. Hero,  III
Venue: Multidimensional Systems and Signal Processing (1998)

Time-frequency (t-f) analysis has clearly reached a certain maturity. One can now often provide striking visual representations of the joint time-frequency energy representation of signals. However, it has been difficult to take advantage of this rich source of information concerning the signal, especially for multidimensional signals. Properly constructed time-frequency distributions enjoy many desirable properties. Attempts to incorporate t-f analysis results into pattern recognition schemes have not been notably successful to date. Aided by Cohen&lsquo;s scale transform one may construct representations from the t-f results which are highly useful in pattern classification. Such methods can produce two dimensional representations which are invariant to time-shift, frequency-shift and scale changes. In addition, two dimensional objects such as images can be represented in a like manner in a four dimensional form. Even so, remaining extraneous variations often defeat the pattern classification approach. This paper presents a method based on noise subspace concepts. The noise subspace enhancement allows one to separate the desired invariant forms from extraneous variations, yielding much improved classification results. Examples from sound classification are discussed.
Spatial join selectivity using power laws
Authors: Christos Faloutsos, Bernhard Seeger, Agma Traina
Venue: ACM SIGMOD Record (2000)

We discovered a surprising law governing the spatial join selectivity across two sets of points. An example of such a spatial join is &ldquo;find the libraries that are within 10 miles of schools&rdquo;. Our law dictates that the number of such qualifying pairs follows a power law, whose exponent we call &ldquo;pair-count exponent&rdquo; (PC). We show that this law also holds for self-spatial-joins (&ldquo;find schools within 5 miles of other schools&rdquo;) in addition to the general case that the two point-sets are distinct. Our law holds for many real datasets, including diverse environments (geographic datasets, feature vectors from biology data, galaxy data from astronomy). In addition, we introduce the concept of the Box-Occupancy-Product-Sum (BOPS) plot, and we show that it can compute the pair-count exponent in a timely manner, reducing the run time by orders of magnitude, from quadratic to linear. Due to the pair-count exponent and our analysis (Law 1), we can achieve accurate selectivity estimates in constant time (O(1)) without the need for sampling or other expensive operations. The relative error in selectivity is about 30% with our fast BOPS method, and even better (about 10%), if we use the slower, quadratic method.
A Numerical Method for the Inverse Stochastic Spectrum Problem
Authors: Moody T. Chu, Quanlin Guo
Venue: SIAM Journal on Matrix Analysis and Applications (1998)

The inverse stochastic spectrum problem involves the construction of a stochastic matrix with a prescribed spectrum. The problem could be solved by first constructing a nonnegative matrix with the same prescribed spectrum. A differential equation aimed to bring forth the steepest descent flow in reducing the distance between isospectral matrices and nonnegative matrices, represented in terms of some general coordinates, is described. The flow is further characterized by an analytic singular value decomposition to maintain the numerical stability and to monitor the proximity to singularity. This flow approach can be used to design Markov chains with specified structure. Applications are demonstrated by numerical examples.
From Potential Theory to Matrix Iterations in Six Steps
Authors: Tobin A. Driscoll, Kim-Chuan Toh, Lloyd N. Trefethen
Venue: SIAM Review (1998)

The theory of the convergence of Krylov subspace iterations for linear systems of equations (conjugate gradients, biconjugate gradients, GMRES, QMR, Bi-CGSTAB, and so on) is reviewed. For a computation of this kind, an estimated asymptotic convergence factor $\rho \le 1$ can be derived by solving a problem of potential theory or conformal mapping. Six approximations are involved in relating the actual computation to this scalar estimate. These six approximations are discussed in a systematic way and illustrated by a sequence of examples computed with tools of numerical conformal mapping and semidefinite programming.
Testing the simplified decision model of telework: a quasi-experimental study
Authors: Stanley D. Clark,  II, Lorne Olfman
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

Virtual organizations that serve customers via the Internet or online service networks have been growing at an incredible rate. These organizations do not require customers to come to the organization's physical location in order to do business. However, many more traditional organizations, even those that support virtual clientele, seem resistant to the use of virtual work arrangements. For organizations to become truly &ldquo;virtual&rdquo; they need to move to alternative work arrangements including to telework. This study explores the resistance to remote work in relation to the decision of employees to telework. Earlier studies by the authors [4-6] have shown that four factors significantly influence the intent of employees to engage in telework. These factors, which together make up the Simplified Decision Model (SDM) are Perceived Legitimacy, Perceived Behavioral Control, Work Social Structure and Commute Distance. This study attempted to confirm the SDM by surveying 407 subjects who were employed in a wide range of organizations in the greater New York City area. Four treatment groups were used to compare how each of the four factors affected Behavioral Intent to telework. Strong confirmation for the relationship described by SDM was found, but the manipulation of factors in the model proved unsuccessful. Methods to better manipulate precursors to Behavioral Intent are discussed.
Interfacing the body's own sensing receptors into neural prosthesis devices
Authors: Morten Haugland, Thomas Sinkjær
Venue: Technology and Health Care (1999)

Functional Electric Stimulation (FES) is today available as a tool in muscle activation used in picking up objects, in standing and walking, in controlling bladder emptying, and for breathing. Despite substantial progress over nearly three decades of development, many challenges remain to provide a more efficient functionality of FES systems. The most important of these is an improved control of the activated muscles. Instead of artificial sensors for feedback, new developments in electrodes to do long-term and reliable recordings from peripheral nerves emphasize the use of the bodys own sensors. These are already installed and optimised through millions of years of natural evolution. This paper presents recent results on a system using electrical stimulation of motor nerves to produce movement and using the natural sensors as feedback signals to control the stimulation that can replicate some of the functions of the spinal cord and its communication with the brain. We have used the nerve signal recorded from cutaneous nerves in two different human applications colon; (1) to replace the external heel switch of a system for correction of spastic drop foot by peroneal stimulation, and (2) to provide an FES system for restoration of hand grasp with sensory feedback from the fingertip. For the bladder function, the sacral root stimulator is a useful control tool in emptying the bladder. To decide when to stimulate, we are at present carrying out experiments on pigs and cats using cuff electrodes on the pelvic nerve and sacral roots to record the neural information from bladder afferents. This information can potentially be used to inhibit unwanted bladder contractions and to trigger the FES system and thereby bladder emptying. Future research will show whether cuffs and other types of electrodes can be used to reliably extract signals from the large number of other receptors in the body to improve and expand on the use of natural sensors in clinical FES systems.
Pricing Patterns of Cellular Phones and Phonecalls: a Segment-Level Analysis
Authors: Dipak C. Jain, Eitan Muller, Naufel J. Vilcassim
Venue: Management Science (1999)

One expectation of the U.S. Federal Communications Commission (FCC) in the early stages of the cellular communications industry was that the presence of two licensees in each market would ensure competition, and thereby result in declining prices over time for both cellular phones (handsets) and phonecalls. However, industry observers have noted recently that although the price of handsets has declined over time, the price of the phonecalls has not. We investigate this interesting pricing issue by modeling the market interaction between the providers of cellular services and also their interaction with customers using a game theoretic framework. A critical assumption in the development of our model is that there exist segments of customers with different valuations, usage levels, and price sensitivities for cellular service. Empirically, we provide support for the existence of two customer segments (viz., Business/Professional and Personal) from both secondary data on industry usage and revenue, and primary data collected from a conjoint analysis study of cellular service customers. From the latter source, we also establish that the Business/Professional customers are more sensitive to prices of phonecalls than the Personal segment. From our analytical model, we characterize the conditions under which penetration and skimming pricing strategies for the handsets are profit-maximizing from the sellers' standpoint, and derive the corresponding price of phonecalls. One of our main analytical results is that a competitive structure can result in lower prices over time for the handset, but higher prices for the phonecalls, depending on production costs of the handset. We are thus able to provide a theoretical explanation for the observed price patterns for the handset and phonecalls.
Update propagation protocols for replicated databates
Authors: Yuri Breitbart, Raghavan Komondoor, Rajeev Rastogi, S. Seshadri, Avi Silberschatz
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

Replication is often used in many distributed systems to provide a higher level of performance, reliability and availability. Lazy replica update protocols, which propagate updates to replicas through independent transactions after the original transaction commits, have become popular with database vendors due to their superior performance characteristics. However, if lazy protocols are used indiscriminately, they can result in non-serializable executions. In this paper, we propose two new lazy update protocols that guarantee serializability but impose a much weaker requirement on data placement than earlier protocols. Further, many naturally occurring distributed systems, like distributed data warehouses, satisfy this requirement. We also extend our lazy update protocols to eliminate all requirements on data placement. The extension is a hybrid protocol that propagates as many updates as possible in a lazy fashion. We implemented our protocols on the Datablitz database system product developed at Bell Labs. We also conducted an extensive performance study which shows that our protocols outperform existing protocols over a wide range of workloads.
Exploiting Sparsity in the Direct Transcription Method for OptimalControl
Authors: John T. Betts, William P. Huffman
Venue: Computational Optimization and Applications (1999)

In the direct transcription method an approximation to an optimal control problem is constructed by discretization of the state and control variables. The control problem is thus transcribed into a large scale constrained optimization problem with a finite number of variables. It is necessary to solve the nonlinear programming (NLP) problem produced by the discretization as efficiently as possible, and research has focused on methods for solving the underlying NLP when the relevant Jacobian and Hessian matrices are sparse. However little attention has been given to computing the Jacobian and Hessian, particularly for applications that require finite difference techniques. Typically it is assumed that these matrices have a block structure, and when standard finite difference estimates are used this operation is a major computational expense. This paper describes how to actually construct the Jacobian and Hessian matrices efficiently, and exploit sparsity inherent in the problem. This new technique can significantly reduce the computational costs when the original optimal control problem has many state and control variables.
Whitney Homology of Semipure Shellable Posets
Authors: Michelle L. Wachs
Venue: Journal of Algebraic Combinatorics: An International Journal (1999)

We generalize results of Calderbank, Hanlon and Robinson on the representation of the symmetric group on the homology of posets of partitions with restricted block size. Calderbank, Hanlon and Robinson consider the cases of block sizes that are congruent to 0 mod d and 1 mod d for fixed d. We derive a general formula for the representation of the symmetric group on the homology of posets of partitions whose block sizes are congruent to k mod d for any k and d. This formula reduces to the Calderbank-Hanlon-Robinson formulas when k &equals; 0, 1 and to formulas of Sundaram for the virtual representation on the alternating sum of homology. Our results apply to restricted block size partition posets even more general than the k mod d partition posets. These posets include the lattice of partitions whose block sizes are bounded from below by some fixed k. Our main tools involve the new theory of nonpure shellability developed by Bj&ouml;rner and Wachs and a generalization of a technique of Sundaram which uses Whitney homology to compute homology representations of Cohen-Macaulay posets. An application to subspace arrangements is also discussed.
Concurrent logic restructuring and placement for timing closure
Authors: Jinan Lou, Wei Chen, Massoud Pedram
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

In this paper, an algorithm for simultaneous logic restructuring and placement is presented. This algorithm first constructs a set of super-cells along the critical paths and then generates the set of non-inferior re-mapping solutions for each supercell. The best mapping and placement solutions for all super-cells are obtained by solving a generalized geometric programming (GGP) problem. The process of identifying and optimizing the critical paths is iterated until timing closure is achieved. Experimental results on a set of MCNC benchmarks demonstrate the effectiveness of our algorithm.