ppxscal/embedding_network huggingface dataset:
Experimental analysis of heart rate variability of long-recording electrocardiograms in normal subjects and patients with coronary artery disease and normal left ventricular function
Authors: S. Nikolopoulos, A. Alexandridi, S. Nikolakeas, G. Manis
Venue: Journal of Biomedical Informatics (2003)

The heart rate signal contains valuable information about cardiac health, which cannot be extracted without the use of appropriate computerized methods. This paper presents an analysis of various electrocardiograms, the aim of which is to categorize them into two distinct groups. Group A represents young male subjects with no prior occurrence of coronary disease events and Group B represents middle-aged male subjects who have symptomatic coronary artery disease without myocardial infarction and whose 12-lead ECGs do not contain any abnormalities, thus wrongly indicating a normal subject. Electrocardiographic recordings are approximately 2 h in length and acquired under conditions that favor the stationarity of collected data. Linear and nonlinear characteristics are studied by applying several techniques including Fourier analysis, Correlation Dimension Estimation, Approximate Entropy, and the Discrete Wavelet Transform. The small variations of the diagnostic information given by each one of the methods as well as the slightly different conclusions among similar studies indicate the necessity of further investigation, combined use, and complementary application of different approaches.
How do IT students stay up to date with employers' skill requirements?
Authors: Tanya McGill, Michael Dixon
Venue: Current issues in IT education (2003)

The information technology industry is subject to rapid change. There have been concerns expressed in the literature about the ability of information technology professionals to keep up to date with developments, and it is likely that it is even more difficult for students to do so. New graduates require marketable skills in order to gain good employment, but the skills most in demand change regularly. This chapter reports on a project that investigated the channels of information that undergraduate and postgraduate telecommunications management and electronic commerce students use to keep up to date with employers' needs. The role of instructors in this process is also discussed.
Enabling Dual-Core Mode in BlueGene/L: Challenges and Solutions
Authors: George Almási, Leonardo R. Bachega, Siddhartha Chatterjee, Manish Gupta, Derek Lieber, Xavier Martorell, José E. Moreira
Venue: Proceedings of the 15th Symposium on Computer Architecture and High Performance Computing (2003)

BlueGene/L is a massively parallel computer system with 65,536 dual-processor compute nodes. The peak performance of BlueGene/L is in excess of 360 TFLOP/s if both processor cores in a node are used for computation. The main challenge of deploying this dual-core mode of operation is that the L1 caches in each core are not hardware coherent. This forces a software-based approach to cache coherence and guides our design of a programming model for dual-core mode. In this paper, we describe the design, implementation, and performance evaluation of system software for enabling the use of dual-core mode on Blue-Gene/L. Our preliminary performance results show that our approach to dual-core mode is effective for key numerical kernels.
Memory leaks in derived types revisited
Authors: G. W. Stewart
Venue: ACM SIGPLAN Fortran Forum (2003)

In a note in the Fortran Forum, Markus describes a technique for avoiding memory leaks with derived types. In this note, we show by a simple example that this technique does not work when the object in question is a parameter in nested subprogram invocations. A fix is proposed and illustrated with code from MATRAN, a Fortran 95 package for performing matrix manipulations.
Evolution of mobile location-based services
Authors: Bharat Rao, Louis Minakakis
Venue: Communications of the ACM (2003)

Utilizing user location as a key determinant of information requirement needs.
Compact suffix array: a space-efficient full-text index
Authors: Veli Mäkinen
Venue: Fundamenta Informaticae (2002)

Suffix array is a widely used full-text index that allows fast searches on the text. It is constructed by sorting all suffixes of the text in the lexicographic order and storing pointers to the suffixes in this order. Binary search is used for fast searches on the suffix array. Compact suffix array is a compressed form of the suffix array that still allows binary searches, but the search times are also dependent on the compression. In this paper, we give efficient methods for constructing and querying compact suffix arrays. We also study practical issues, such as the trade off between compression and search times, and show how to reduce the space requirement of the construction. Experimental results are provided in comparison with other search methods. With a large text corpora, the index took 1.6 times the size of the text, while the searches were only two times slower than from a suffix array.
Effects of frequency offset compensation error on channel estimation for OFDM system under mobile radio channels
Authors: Seung Young Park, Bo Seok Seo, Chung Gu Kang
Venue: Signal Processing (2003)

In this paper, we analyze the effects of frequency offset compensation on the pilot-assisted channel estimation for the orthogonal frequency division multiplexing system under a time-variant multipath fading channel. The analysis focuses on the pilot arrangement of a pilot-assisted channel estimation scheme, in which the minimum mean-square error channel estimation is employed to exploit both time- and frequency-domain correlation characteristics of the frequency response of time-variant multipath fading channels. We also investigate the effect of the length of the training signal used for frequency offset estimation on the channel estimation and subsequently, on the bit error rate performance, subject to varying signal-to-noise power ratio under mobile radio channel. Numerical results show that the maximum allowable pilot carrier spacing in time-domain is critically affected by the frequency offset error. In addition, a proper length of the training signal must be configured to suppress the noise influence while reducing a systematic error due to the time-variant behavior of the channel.
Functional design and implementation of graphical user interfaces for theorem provers
Authors: C. Lüth, B. Wolff
Venue: Journal of Functional Programming (1999)

The design of theorem provers, especially in the LCF-prover family, has strongly profited from functional programming. This paper attempts to develop a metaphor suited to visualize the LCF-style prover design, and a methodology for the implementation of graphical user interfaces for these provers and encapsulations of formal methods. In this problem domain, particular attention has to be paid to the need to construct a variety of objects, keep track of their interdependencies and provide support for their reconstruction as a consequence of changes. We present a prototypical implementation of a generic and open interface system architecture, and show how it can be instantiated to an interface for Isabelle, called IsaWin, as well as to a tailored tool for transformational program development, called TAS.
SysRel: an interactive application for training
Authors: Rodica BACIU
Venue: ACM SIGCSE Bulletin (2003)

The proposal work describes a simulation developed to demonstrate different methods of computing the reliability of systems.
Program optimization: enforcement of local access and array access via pointers
Authors: Timothy J. Rolfe
Venue: ACM SIGCSE Bulletin (2003)

Matrix multiplication in linear algebra provides a useful problem through which one can investigate optimizations based on local access to memory rather than scattered access, and on the use of pointers in places of array subscripting. Benchmarking results favor a pointer-based implementation with a reordering of the three loops in the definition.
A Digital and Wide Power Bandwidth H-Field Generator for Automatic Test Equipment
Authors: Fengming Zhang, Y. J. Lee, T. Kane, L. Schiano, M. Momenzadeh, Y.-B. Kim, F. J. Meyer, F. Lombardi, S. Max, Phil Perkinson
Venue: Proceedings of the 18th IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems (2003)

Recent research on modeling timing jitter has raised a requirement for a predictable, high magnitude, uniform, and wide bandwidth H-field. In this paper, a novel H-field generator design methodology is proposed. It consists of a single layer air core solenoid and a digital power switch driver that takes advantage of low power, wide bandwidth, and big current-driven capability. With input overdrive voltage, the digital switch can drive rail-to-rail voltage with output current up to 16A and power bandwidth more than 3 MHz.This paper demonstrates a novel solenoid driver circuit to generate an accurate H-field by comparing digital and analog approaches and comparing the experimental data with the theoretical data.
Oxygen vacancy defects in tantalum pentoxide: a density functional study
Authors: R. Ramprasad, Michael Sadd, Doug Roberts, Tom Remmel, Mark Raymond, Eric Luckowski, Sriram Kalpat, Carole Barron, Mel Miller
Venue: Microelectronic Engineering (2003)

First principles total energy calculations were performed in order to characterize O vacancy defects in Ta2O5. A simplified version of the crystalline orthorhombic phase of Ta2O5 was used in this study. Results indicate that O vacancies in Ta2O5 can be broadly classified based on their location in the lattice. One type of vacancy (occupying the 'in-plane' sites) displays deep or mid gap occupied states, and shallow unoccupied states, while a second type (occupying 'cap' sites) results in shallow occupied states. For a wide range of local Fermi level or chemical potential, the neutral and +2 charged states of the in-plane type vacancy and the +2 charge state of the cap type vacancy are found to be most stable.
Best-Effort Low-Delay Service
Authors: Jörg Diederich, Mark Doll, Martina Zitterbart
Venue: Proceedings of the 28th Annual IEEE International Conference on Local Computer Networks (2003)

The Differentiated Services (DiffServ) approach is intendedto provide Quality of Service (QoS) in IP-based networks.This is a very important issue not only in wirelinefixed networks but also in IP-based wireless mobile networks.Currently, services within the DiffServ approach includingPremium Service, Assured Service and Best-EffortService are intended for fixed networks. We have proposedthe Mobile Differentiated Services QoS model [5] to enhancethe above services so they are better suited for wirelessmobile networks. One part of this QoS model is the so-calledBest-Effort Low-Delay (BELD) Service which has thesame low-delay and low-jitter characteristic as PremiumService, but a certain probability for packet loss. This serviceis especially suited for delay-sensitive and loss-tolerantapplications and can take favor of unused Premium Serviceresources to increase the network utilization. This paperpresents details on the BELD Service including initial simulationresults showing the feasibility of BELD service.
Definability and compression
Authors: Foto Afrati, Hans Leiß, Michel de Rougemont
Venue: Fundamenta Informaticae (2002)

A compression algorithm takes a finite structure of a class K as input and produces a finite structure of a different class K' as output. Given a property P on the class K defined in a logic L, we study the definability of property P on the class K'. We consider two compression schemes on unary ordered structures (strings), compression by run-length encoding and the classical Lempel-Ziv-78 scheme.First-order properties of strings are first-order on run-length compressed strings, but this fails for images, i.e. 2-dimensional strings. We present simple first-order properties of strings which are not first-order definable on strings compressed with the Lempel-Ziv-78 compression scheme.We show that all properties of strings that are first-order definable on strings are definable on Lempel-Ziv compressed strings in FO(TC), the extension of first-order logic with the transitive closure operator. We define a subclass F of the first-order properties of strings such that if P is a property in F, it is also first-order definable on the Lempel-Ziv compressed strings. Monadic second-order properties of strings, i.e. regular languages, are dyadic second-order definable on Lempel-Ziv compressed strings.
Visualization of Rule's Similarity using Multidimensional Scaling
Authors: Shusaku Tsumoto, Shoji Hirano
Venue: Proceedings of the Third IEEE International Conference on Data Mining (2003)

One of the most important problems with rule inductionmethods is that it is very difficult for domain experts to checkmillions of rules generated from large datasets. The discoveryfrom these rules requires deep interpretation from domainknowledge. Although several solutions have been proposedin the studies on data mining and knowledge discovery,these studies are not focused on similarities betweenrules obtained. When one rule r1 has reasonable featuresand the other rule r2 with high similarity to r1 includes unexpectedfactors, the relations between these rules will becomea trigger to the discovery of knowledge. In this paper,we propose a visualization approach to show the similarrelations between rules based on multidimensional scaling,which assign a two-dimensional cartesian coordinateto each data point from the information about similiariesbetween this data and others data. We evaluated this methodon two medical data sets, whose experimental results showthat knowledge useful for domain experts could be found.
Local adaptation luminance via segmentation and assimilation
Authors: Yangli Hector Yee, Sumanta Pattanaik
Venue: ACM SIGGRAPH 2003 Sketches Applications (2003)

We present a novel method for computing local adaptation luminance that can be used with several different visual adaptation based tone-reproduction operators for displaying high dynamic range images.
Learning Rules for Anomaly Detection of Hostile Network Traffic
Authors: Matthew V. Mahoney, Philip K. Chan
Venue: Proceedings of the Third IEEE International Conference on Data Mining (2003)

We introduce an algorithm called LERAD that learnsrules for finding rare events in nominal time-series datawith long range dependencies. We use LERAD to findanomalies in network packets and TCP sessions to detectnovel intrusions. We evaluated LERAD on the 1999DARPA/Lincoln Laboratory intrusion detection evaluationdata set and on traffic collected in a universitydepartmental server environment.
Design of random noise generator using SW algorithm
Authors: Jinkeun Hong, Sunchun Park, Janghong Yoon, Jaeyoung Koh, Daeho Kim
Venue: Proceedings of the 1st international symposium on Information and communication technologies (2003)

A random noise generator uses a non-deterministic source to produce randomness. Most operate by measuring unpredictable natural processes, such as thermal noise, atmospheric noise, or nuclear decay. Critical cryptography applications require the production of an unpredictable and unbiased stream of binary data derived from a fundamental noise mechanism. In this paper, we proposed a random noise generator with Gaussian noise using filtering algorithm. The proposed scheme is designed to reduce the statistical property of the biased bit stream in the output of a random noise generator.
Binary Partitioning, Perceptual Grouping, and Restoration with Semidefinite Programming
Authors: Jens Keuchel, Christoph Schnörr, Christian Schellewald, Daniel Cremers
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

We introduce a novel optimization method based on semidefinite programming relaxations to the field of computer vision and apply it to the combinatorial problem of minimizing quadratic functionals in binary decision variables subject to linear constraints. The approach is (tuning) parameter-free and computes high-quality combinatorial solutions using interior-point methods (convex programming) and a randomized hyperplane technique. Apart from a symmetry condition, no assumptions (such as metric pairwise interactions) are made with respect to the objective criterion. As a consequence, the approach can be applied to a wide range of problems. Applications to unsupervised partitioning, figure-ground discrimination, and binary restoration are presented along with extensive ground-truth experiments. From the viewpoint of relaxation of the underlying combinatorial problem, we show the superiority of our approach to relaxations based on spectral graph theory and prove performance bounds.
Energy-based models for sparse overcomplete representations
Authors: Yee Whye Teh, Max Welling, Simon Osindero, Geoffrey E. Hinton
Venue: The Journal of Machine Learning Research (2003)

We present a new way of extending independent components analysis (ICA) to overcomplete representations. In contrast to the causal generative extensions of ICA which maintain marginal independence of sources, we define features as deterministic (linear) functions of the inputs. This assumption results in marginal dependencies among the features, but conditional independence of the features given the inputs. By assigning energies to the features a probability distribution over the input states is defined through the Boltzmann distribution. Free parameters of this model are trained using the contrastive divergence objective (Hinton, 2002). When the number of features is equal to the number of input dimensions this energy-based model reduces to noiseless ICA and we show experimentally that the proposed learning algorithm is able to perform blind source separation on speech data. In additional experiments we train overcomplete energy-based models to extract features from various standard data-sets containing speech, natural images, hand-written digits and faces.
Fundamentals of system simulation
Authors: G. I. Papadimitriou, B. Sadoun, C. Papazoglou
Venue: Applied system simulation: methodologies and applications (2003)

Simulation is a powerful tool that can be used to mimic the behavior of almost any system. This chapter provides an overview of the basics of applied system simulation. In order for the simulation results to be useful for decision making, the model must be verified and validated. An understanding of random number generation and random variate generation is essential before embarking on any simulation project. The programming language or software package that will be used to translate the model into a computerized form must be chosen carefully based on the objectives and requirements of the simulation study. Furthermore, simulation experiments must be conducted in order to understand the behavior of the system under study.
Virtual teams: a review of current literature and directions for future research
Authors: Anne Powell, Gabriele Piccoli, Blake Ives
Venue: ACM SIGMIS Database (2004)

Information technology is providing the infrastructure necessary to support the development of new organizational forms. Virtual teams represent one such organizational form, one that could revolutionize the workplace and provide organizations with unprecedented levels of flexibility and responsiveness. As the technological infrastructure necessary to support virtual teams is now readily available, further research on the range of issues surrounding virtual teams is required if we are to learn how to manage them effectively. While the findings of team research in the traditional environment may provide useful pointers, the idiosyncratic structural and contextual issues surrounding virtual teams call for specific research attention.This article provides a review of previously published work and reports on the findings from early virtual team research in an effort to take stock of the current state of the art. The review is organized around the input - process - output model and categorizes the literature into issues pertaining to inputs, socio-emotional processes, task processes, and outputs. Building on this review we critically evaluate virtual team research and develop research questions that can guide future inquiry in this fertile are of inquiry.
A Subquadratic Sequence Alignment Algorithm for Unrestricted Scoring Matrices
Authors: Maxime Crochemore, Gad M. Landau, Michal Ziv-Ukelson
Venue: SIAM Journal on Computing (2003)

Given two strings of size $n$ over a constant alphabet, the classical algorithm for computing the similarity between two sequences [D. Sankoff and J. B. Kruskal, eds., {Time Warps, String Edits, and Macromolecules}; Addison--Wesley, Reading, MA, 1983; T. F. Smith and M. S. Waterman, { J.\ Molec.\ Biol., 147 (1981), pp. 195--197] uses a dynamic programming matrix and compares the two strings in O(n2) time. We address the challenge of computing the similarity of two strings in subquadratic time for metrics which use a scoring matrix of unrestricted weights. Our algorithm applies to both {local} and {global} similarity computations. The speed-up is achieved by dividing the dynamic programming matrix into variable sized blocks, as induced by Lempel--Ziv parsing of both strings, and utilizing the inherent periodic nature of both strings. This leads to an $O(n^2 / \log n)$, algorithm for an input of constant alphabet size. For most texts, the time complexity is actually $O(h n^2 / \log n)$, where $h \le 1$ is the entropy of the text. We also present an algorithm for comparing two {run-length} encoded strings of length m and n, compressed into m' and n' runs, respectively, in O(m'n + n'm) complexity. This result extends to all distance or similarity scoring schemes that use an additive gap penalty.
Markov's property and generalized Pad&#x00E9;-type approximants
Authors: Nicholas J. Daras
Venue: Proceedings of the international conference on Computational methods in sciences and engineering (2003)

Padé approximants are rational functions whose expansion in ascending powers of the variable coincides with the Taylor power series expansion of analytic functions into a disk as far as possible, that is up to the sum of the degree of the numerator and denominator. The numerator and denominator of a Padé approximant are completely determined by this condition and no freedom is left. On the contrary, Padé-type approximants are rational functions with an arbitrary denominator, whose numerator is determined by the condition that the expansion of the Padé-type approximant matches the Taylor expansion of analytic functions up to the degree of the numerator. The great advantage of Padé-type approximants over Padé approximants lies in the free choice of the poles which may lead to a better approximation ([2-6]).
Evaluation of web usage mining approaches for user's next request prediction
Authors: Mathias Géry, Hatem Haddad
Venue: Proceedings of the 5th ACM international workshop on Web information and data management (2003)

Analysis of Web server logs is one of the important challenge to provide Web intelligent services.In this paper, we describe a framework for a recommender system that predicts the user's next requests based on their behaviour discovered from Web Logs data. We compare results from three usage mining approaches: association rules, sequential rules and generalised sequential rules. We use two selection rules criteria: highest confidence and last-subsequence. Experiments are performed on three collections of real usage data: one from an Intranet Web site and two from an Internet Web site.