ppxscal/embedding_network huggingface dataset:
A Sequential Regularization Method for Time-Dependent Incompressible Navier--Stokes Equations
Authors: Ping Lin
Venue: SIAM Journal on Numerical Analysis (1997)

The objective of the paper is to present a method, called the sequential regularization method (SRM), for the nonstationary incompressible Navier--Stokes equations from the viewpoint of regularization of differential-algebraic equations (DAEs), and to provide a way to apply a DAE method to partial differential-algebraic equations (PDAEs). The SRM is a functional iterative procedure. It is proved that its convergence rate is $O(\epsilon^m)$, where $m$ is the number of the SRM iterations and $\epsilon$ is the regularization parameter. The discretization and implementation issues of the method are considered. In particular, a simple explicit-difference scheme is analyzed and its stability is proved under the usual step-size condition of explicit schemes. It appears that the SRM formulation is new in the Navier--Stokes context. Unlike other regularizations or pseudocompressibility methods in the Navier--Stokes context, the regularization parameter $\epsilon$ in the SRM need not be very small and the regularized problem in the sequence may be essentially nonstiff in time direction for any $\epsilon$. Hence the stability condition is independent of $\epsilon$ even for explicit time discretization. Numerical experiments are given to verify our theoretical results.
A Novel Class AB CMOS Power Amplifier
Authors: Henrik Sjöland, Sven Mattisson
Venue: Analog Integrated Circuits and Signal Processing (1997)

A novel class AB design is described. To achieve a large output voltage swing and to avoid the offset problems associated with a class AB input stage, the non-linearity is placed between the input and the output stage. Before the output stage the signal is separated in one positive and one negative half, which are then amplified separately.For the first time this topology is used in an integrated CMOS power amplifier. It operates with &plus;/ &minus;2.5 V supplies and can drive more than 4 {\rm V_{pp}} into an 8 &omega; load.
RASSP Methodology Evaluation and Lessons Learned Developing IRST Signal Processor
Authors: Larry Scanlan, Wing Lee, Mike Vahey, Mike McCollough
Venue: Journal of VLSI Signal Processing Systems (1997)

The development of a real-time infrared search and track (IRST) processing system served as a real-world test of progress toward the fourfold reduction in cycle time expected at the end of the four-year Rapid Prototyping of Application Specific Signal Processors (RASSP) program. This signal processor development tested the effectiveness of the RASSP methodology and processes and provided critical metrics to evaluate the 4X roadmap. Virtual Prototyping, a VHDL technique for validating hardware and software design before building hardware, makes the RASSP top-down methodology unique. This paper describes the 4X roadmap for cycle time improvement, our experiences with virtual prototyping and important lessons learned for improving the methodology.
Higher-order statistics: a robust vehicle for diagnostic assessment and characterisation of lung sounds
Authors: Leontios J. Hadijileontiadis, Stavros M. Panas
Venue: Technology and Health Care (1997)

The use of higher-order statistics for diagnostic assessment and characterisation of lung sounds is presented in this article. The parametric approach of bispectrum estimation, which is a third-order spectrum, based on a non-Gaussian white noise driven autoregressive (AR) model, reveals information about lung sounds that is not contained in the ordinary power spectrum, such as the degree of nonlinearity and deviations from normality. Characterisation of source and transmission of lung sounds is achieved using an AR model based on third-order statistics. Furthermore, harmonic analysis of lung sounds is combined with the bicoherence index in order to obtain information regarding possible quadratic phase coupling among harmonic components of musical lung sounds. Experiments have shown that higher-order statistics can offer reliable evaluation of lung sounds characteristics, since their general properties and robustness in noiseless or noisy environments (lung sounds contaminated with additive symmetrical noise, e.g., Gaussian) proved to have superior advantages in objective analysis of pulmonary dysfunction.
Boundary Exact Controllability of Interface Problems with Singularities II: Addition of Internal Controls
Authors: Serge Nicaise
Venue: SIAM Journal on Control and Optimization (1997)

We prove the exact controllability by boundary action of hyperbolic interface problems with singularities. The two proposed methods consist of acting by a classical boundary control whose support does not contain a neighborhood of the singular points and adding internal controls located near these singular points. (See [M.-T. Niane and O. Seck, C. R. Acad. Sci. Paris Sér. I, 318 (1994), pp. 945--948; A. Heibig and M. Moussaoui, Disc. Cont. Dynam. Syst., 2 (1996), pp. 367--386; M.-T. Niane and O. Seck, C. R. Acad. Sci. Paris Sér. I, 316 (1993), pp. 695--700], where such a method was introduced.)
Efficiently supporting ad hoc queries in large datasets of time sequences
Authors: Flip Korn, H. V. Jagadish, Christos Faloutsos
Venue: Proceedings of the 1997 ACM SIGMOD international conference on Management of data (1997)

Ad hoc querying is difficult on very large datasets, since it is usually not possible to have the entire dataset on disk. While compression can be used to decrease the size of the dataset, compressed data is notoriously difficult to index or access. In this paper we consider a very large dataset comprising multiple distinct time sequences. Each point in the sequence is a numerical value. We show how to compress such a dataset into a format that supports ad hoc querying, provided that a small error can be tolerated when the data is uncompressed. Experiments on large, real world datasets (AT T customer calling patterns) show that the proposed method achieves an average of less than 5% error in any data value after compressing to a mere 2.5% of the original space (i.e., a 40:1 compression ratio), with these numbers not very sensitive to dataset size. Experiments on aggregate queries achieved a 0.5% reconstruction error with a space requirement under 2%.
AFS and the Web: competitors or collaborators?
Authors: M. Satyanarayanan, Mirjana Spasojevic
Venue: ACM SIGOPS Operating Systems Review (1997)

Over the last few years, the World-Wide Web [2] has risen to dominance as a mechanism for wide-area information access. Each day brings new reports of the growth of the Web, and this trend shows no signs of abating any time soon. To many people, the Web and the Internet are synonymous. Unfortunately, success has exposed many limitations of the Web such as its tendency to overload the network and servers, its limited ability to control access to sensitive data, its lack of mechanisms for data consistency, and its susceptibility to network and server failures. It is now widely recognized that these problems must be solved for the continued growth of the Web.With much less fanfare, another world-wide information system, AFS, has also been operational on the Internet. AFS was originally designed to support the file sharing needs of a campus-sized community of five to seven thousand workstations [11, 15]. In current parlance, AFS was conceived as an information sharing mechanism for the Intranet of an organization. Since then, AFS has been evolved to function effectively over the Internet [17, 21]. Many organizations have been part of a single distributed Unix file name space supported by AFS. As of 1994, this system spanned well over 100 organizations world-wide, with each organization typically containing many tens or hundreds of clients. Measurements reported in a recent paper [20] confirm that AFS does indeed function effectively at this scale.The goal of this paper is to critically compare these two mechanisms for world-wide information access. We begin by asking the following questions: bull; What are the relative strengths and weaknesses of the two mechanisms? bull; Which of these differences are superficial, and which are deep? bull; Why is the Web so much more visible and popular?In performing this comparison, it is important to keep in mind that the two mechanisms are not addressing precisely the same problem. While AFS has the relatively narrow and well-defined goal of provided distributed Unix file access, the goal of the Web is broader and less explicit. Further, AFS is now stable and mature while many aspects of the Web are still evolving. In spite of these caveats, we believe that a comparison of the two mechanisms will provide useful insights.Our comparison shows that the Web and AFS are not really competing technologies. Rather, they represent complementary technologies that may be used together for mutual advantage. We present real-life examples to confirm that this potential can indeed be realized in practice.
An interpretation of index term weighting schemes based on document components
Authors: K. L. Kwok
Venue: Proceedings of the 9th annual international ACM SIGIR conference on Research and development in information retrieval (1986)

A theory of indexing is presented and is based on viewing a document as constituted of components. A component may be chosen as any run of text unit that can be: (a) judged as to its relevancy property; and (b) considered as independent within the document. By looking at the constituent components of a document in relation to the universe of all components from the collection, we have been able to apply Bayes' decision theory to derive the index term representation for the document, as well as attaching an initial probabilistic weight for each term based on a Principle of Document Self-Recovery. It turns out that different choices of document components, such as a word or a whole abstract, can lead to different term weighting schemes that have been introduced before and are based on probability considerations; specifically, Edmundson and Wyllys' term significance formula, Sparck Jones' inverse document frequency, and later modified by Croft and Harper into the 'combination match' formula. Thus, a unified interpretation of various probabilistic term weighting schemes appears possible.
Detection and Recognition of Periodic, Nonrigid Motion
Authors: Ramprasad Polana, Randal C. Nelson
Venue: International Journal of Computer Vision (1997)

The recognition of nonrigid motion, particularly that arising from human movement (and by extension from the locomotory activity of animals) has typically made use of high-level parametric models representing the various body parts (legs, arms, trunk, head etc.) and their connections to each other. Such model-based recognition has been successful in some cases; however, the methods are often difficult to apply to real-world scenes, and are severely limited in their generalizability. The first problem arises from the difficulty of acquiring and tracking the requisite model parts, usually specific joints such as knees, elbows or ankles. This generally requires some prior high-level understanding and segmentation of the scene, or initialization by a human operator. The second problem, with generalization, is due to the fact that the human model is not much good for dogs or birds, and for each new type of motion, a new model must be hand-crafted. In this paper, we show that the recognition of human or animal locomotion, and, in fact, any repetitive activity can be done using low-level, non-parametric representations. Such an approach has the advantage that the same underlying representation is used for all examples, and no individual tailoring of models or prior scene understanding is required. We show in particular, that repetitive motion is such a strong cue, that the moving actor can be segmented, normalized spatially and temporally, and recognized by matching against a spatio-temporal template of motion features. We have implemented a real-time system that can recognize and classify repetitive motion activities in normal gray-scale image sequences. Results on a number of real-world sequences are described.
Determining end-to-end delay bounds in heterogeneous networks
Authors: Pawan Goyal, Simon S. Lam, Harrick M. Vin
Venue: Multimedia Systems (1997)

We define a class of Guaranteed Rate (GR) scheduling algorithms. The GR class includes Virtual Clock, Packet-by-Packet Generalized Processor Sharing and Self-Clocked Fair Queuing. For networks that employ scheduling algorithms belonging to GR, we present a method for determining an upper bound on end-to-end delay. The method facilitates determination of end-to-end delay bounds for a Variety of sources. We illustrate the method by determining end-to-end delay bounds for sources conforming to Leaky Bucket and exponentially bounded burstiness.
The Case for Chaotic Adaptive Routing
Authors: Kevin Bolding, Melanie Fulgham, Lawrence Snyder
Venue: IEEE Transactions on Computers (1997)

Chaotic routers are randomizing, nonminimal adaptive packet routers designed for use in the communication networks of parallel computers. Chaotic routers combine the flexibility found in adaptive routing with a design simple enough to be competitive with the most streamlined oblivious routers. We review chaotic routing and compare it with other contemporary network routing approaches, including state-of-the-art oblivious and adaptive routers. A detailed head-to-head comparison between oblivious, minimal adaptive, and chaotic routing is then presented, exploring the performance of comparable VLSI implementations through analysis and simulation. The results indicate that chaotic routers provide very effective and efficient high-performance message routing.
Compatible genericity with run-time types for the Java programming language
Authors: Robert Cartwright, Guy L. Steele,  Jr.
Venue: ACM SIGPLAN Notices (1998)

The most serious impediment to writing substantial programs in the Java trade; programming language is the lack of a gentricity mechanism for abstracting classes and methods with respect to type. During the past two years, several research groups have developed Java extensions that support various forms of genericity, but none has succeeded in accommodating general type parameterization (akin to Java arrays) while retaining compatibility with the existing. Java Virtual Machine. In this paper, we explain how to support general type parameterization---including both non-variant and covariant subtyping---on top of the existing Java Virtual Machine at the cost of a larger code footprint and the forwarding of some method calls involving parameterized classes and methods. Our language extension is forward and backward compatible with the Java 1.2 language and run-time environment: programs in the extended language will run on existing Java 1.2 virtual machines (relying only on the unparameterized Java core libraries) and all existing Java 1.2 programs have the same binary representation and semantics (behavior) in the extended language.
Interference-Minimizing Colorings of Regular Graphs
Authors: P. C. Fishburn, J. H. Kim, J. C. Lagarias, P. E. Wright
Venue: SIAM Journal on Discrete Mathematics (1998)

Communications problems that involve frequency interference, such as the channel assignment problem in the design of cellular telephone networks, can be cast as graph coloring problems in which the frequencies (colors) assigned to an edge's vertices interfere if they are too similar. The paper considers situations modeled by vertex-coloring d-regular graphs with n vertices using a color set 1, 2,..., n, where colors i and j are said to interfere if their circular distance $\min \{ | i-j | , n- | i-j | \}$ does not exceed a given threshold value $\alpha$. Given a d-regular graph G and threshold $\alpha$, an interference-minimizing coloring is a coloring of vertices that minimizes the number of edges that interfere. Let $I_\alpha (G)$ denote the minimum number of interfering edges in such a coloring of $G$. For most triples $(n, \alpha ,d),$ we determine the minimum value of $I_\alpha (G)$ over all d-regular graphs and find graphs that attain it. In determining when this minimum value is 0, we prove that for $r \geq 3$ there exists a d-regular graph G on n vertices that is r-colorable whenever $d \leq (1- \frac{1}{r}) n-1$ and nd is even. We also study the maximum value of $I_\alpha (G)$ over all d-regular graphs and find graphs that attain this maximum in many cases.
Algorithms for Finding Repeated Game Equilibria
Authors: Mark B. Cronshaw
Venue: Computational Economics (1997)

This paper describes computational techniques for finding all equilibria in infinitely repeated games with discounting and perfect monitoring. It illustrates these techniques with a three player Cournot game. This is the first infinitely repeated three player game ever solved. The paper also presents the solution for the set of equilibria in a two country tariff war. In both games the set of equilibria is large even when the players are not patient.
TRW/TED Accelerometer Wafer Process Production Facility: manufacturing simulation
Authors: Lawrence S. Farey
Venue: Proceedings of the 28th conference on Winter simulation (1996)

Simulation is a cost affective way to analyze and make improvements to dynamic complex manufacturing systems, such as senii conductor processing. The TRW/TED Accelerometer Wafer Process Production Facility is a semi conductor processing facility which makes automotive air bag sensors. A manufacturing simulation of the facility was developed to determine what changes could be made to the facility and/or personnel to maximize production of the sensor chips. A simulation model of the existing facility was developed and validated. Eight experiment models were built. The models included adding: lot starts, a second shift, personnel to the first shift, equipment, personnel and equipment, personnel and a second shift, changing process times, and eliminating process steps. Throughput was chosen as the performance criteria to determine the alternatives effectiveness. The model for the existing conditions indicated a production throughput of 825,552 chips per year. Experiment model which added personnel and a second shift produced the greatest increase in throughput, 2,555,280 chips per year. This is an increase of 210% over the existing conditions. The conclusion is to add personnel to the first shift and add a second shift. The conclusion was based on operational, technical and physical data, it did not take into consideration financial objectives. Using cost information in the analysis will give a more accurate solution.
Large-Scale Simulation Studies in Image Pattern Recognition
Authors: Tin Kam Ho, Henry S. Baird
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

Many obstacles to progress in image pattern recognition result from the fact that per-class distributions are often too irregular to be well-approximated by simple analytical functions. Simulation studies offer one way to circumvent these obstacles. We present three closely related studies of machine-printed character recognition that rely on synthetic data generated pseudorandomly in accordance with an explicit stochastic model of document image degradations. The unusually large scale of experiments¿involving several million samples¿that this methodology makes possible has allowed us to compute sharp estimates of the intrinsic difficulty (Bayes risk) of concrete image recognition problems, as well as the asymptotic accuracy and domain of competency of classifiers.
Optimization of a hierarchical file organization for spelling correction
Authors: Tetsuro Ito, Clement T. Yu
Venue: Proceedings of the 8th annual international ACM SIGIR conference on Research and development in information retrieval (1985)

A spelling program using a hierarchically organized file seems to be promising, since it can correct more than common typing mistakes. However, its speed of detecting spelling errors in the inputs is rather slow. Here some techniques of modifying the program to improve the speed are presented.
Exception-based information flow control in object-oriented systems
Authors: Elisa Bertino, Sabrina De Capitani Di Vimercati, Elena Ferrari, Pierangela Samarati
Venue: ACM Transactions on Information and System Security (TISSEC) (1998)

We present an approach to control information flow in object-oriented systems. The decision of whether an information flow is permitted or denied depends on both the authorizations specified on the objects and the process by which information is obtained and transmitted. Depending on the specific computations, a process accessing sensitive information could still be allowed to release information to users who are not allowed to directly access it. Exceptions to the permissions and restrictions stated by the authorizations are specified by means of exceptions associated with methods. Two kinds of exceptions are considered: invoke exceptions, applicable during a mehtod execution and reply exceptions applicable to the information returned by a method. Information flowing from one object into another or returned to the user is subject to the different exceptions specified for the methods enforcing the transmission. We formally characterize information transmission and flow in a transaction and define the conditions for safe information flow. We define security specifications and characterize safe information flows. We propose an approach to control unsafe flows and present an algorithm to enforce it. We also illustrate an efficient implementation of our controls and present some experimental results evaluating its performance.
Extracting Reusable Functions by Flow Graph-Based Program Slicing
Authors: Filippo Lanubile, Giuseppe Visaggio
Venue: IEEE Transactions on Software Engineering (1997)

An alternative approach to developing reusable components from scratch is to recover them from existing systems. In this paper, we apply program slicing, a program decomposition method, to the problem of extracting reusable functions from ill-structured programs. As with conventional slicing first described by Weiser, a slice is obtained by iteratively solving data flow equations based on a program flow graph. We extend the definition of program slice to a transform slice, one that includes statements which contribute directly or indirectly to transform a set of input variables into a set of output variables. Unlike conventional program slicing, these statements do not include either the statements necessary to get input data or the statements which test the binding conditions of the function. Transform slicing presupposes the knowledge that a function is performed in the code and its partial specification, only in terms of input and output data. Using domain knowledge we discuss how to formulate expectations of the functions implemented in the code. In addition to the input/output parameters of the function, the slicing criterion depends on an initial statement, which is difficult to obtain for large programs. Using the notions of decomposition slice and concept validation we show how to produce a set of candidate functions, which are independent of line numbers but must be evaluated with respect to the expected behavior. Although human interaction is required, the limited size of candidate functions makes this task easier than looking for the last function instruction in the original source code.
A course on multimedia technology for computer science and computer engineering students
Authors: Douglas S. Reeves
Venue: ACM SIGCSE Bulletin (1997)

We have developed a new course on Multimedia Technology, intended for upper-level undergraduates and graduate students majoring in either Computer Science or Computer Engineering. In this paper we describe the topics covered, the method of instruction, the work done by the students, and the facilities needed to teach such a course. The paper concludes with some feedback provided by students, and possible ways in which the course could be improved or extended.