ppxscal/embedding_network huggingface dataset:
Approximation algorithms for clustering streams and large data sets
Authors: Rajeev Motwani
Venue:  (2003)

As data collection and storage become easier and cheaper, corporate and research data warehouses have proliferated and grown. In exploring the ways in which these vast resources can be used, datamining algorithm designers face new problems that arise due to the size and nature of many data sets. The amount of data that can be stored on a set of disks has far outstripped the quantity that can be processed in the main memory of a computer, and in many cases it is desirable to process information as it is generated, and then discard all but a short synopsis. New data models that reflect the importance of processing a large amount of data using a small amount of space and time have been developed which allow the designers of new algorithms to evaluate the relative benefits of various approaches. We will discuss three such models, each with different algorithmic requirements: the Very Large Data Set model, which applies to static data sets stored on distributed systems but larger than main memory; the Data Stream model, which applies to static data sets larger than main memory that are stored on slow, linearly accessible devices; and the Sliding Window model, which assumes a data set that may be in the process of being generated, without any foreseen end, of which, at any moment, only a recent segment (which is much larger than main memory) is of interest. Clustering, or grouping data into representative subsets, is a tool commonly used in data analysis, and can often make the manipulation of large data sets simpler. For example, a search engine could cluster the pages returned by a query, and then return a summary of the categories of pages found, enabling a user to narrow or change the search without reading through a long list of results. We will present algorithms for variants of the clustering problems known as k-Median and k-Center, both NP-Hard problems that admit good approximation algorithms. For each of the above-mentioned data models, we will present constant-factor approximation algorithms for various versions of k-Median and k-Center.
On a Square Packing Problem
Authors: S. Boucheron, W. Fernandez De LaVega
Venue: Combinatorics, Probability and Computing (2002)

An instance of the square packing problem consists of n squares with independently, uniformly distributed side-lengths and independently, uniformly distributed locations on the unit d-dimensional torus. A packing is a maximum family of pairwise disjoint squares. The one-dimensional version of the problem is the classical random interval packing problem. This paper deals with the asymptotic behaviour of packings as n tends to infinity while d = 2. Coffman, Lueker, Spencer and Winkler recently proved that the average size of packing is &Theta;(nd&#x002F;(d+1)). Using partitioning techniques, sub-additivity and concentration of measure arguments, we show first that, after normalization by n2&#x002F;3, the size of two-dimensional square packings tends in probability toward a genuine limit &gamma;. Straightforward concentration arguments show that large fluctuations of order n2&#x002F;3 should have probability vanishing exponentially fast with n2&#x002F;3. Even though &gamma; remains unknown, using a change of measure argument we show that this upper bound on tail probabilities is qualitatively correct.
A Hypersphere Oriented Key Exchange Scheme for Multiparty
Authors: Chin-Chen Chang, Chao-Wen Chan
Venue: Proceedings of the 2003 International Conference on Computer Networks and Mobile Computing (2003)

The paper proposes a new key exchange scheme that is based on hyperspherical equation. Each participant fairly contributes a piece of final radius of a hypersphere. Thus, the proposed scheme can be modified to support the dynamic behavior of communication patterns of the peer-to-peer dynamic group.
Enumeration of Optimal Ternary Constant-Composition Codes
Authors: G. T. Bogdanova, S. N. Kapralov
Venue: Problems of Information Transmission (2003)

The problem of classification of optimal ternary constant-composition codes is considered. Using a combinatorial-computer method, the number of inequivalent codes is determined for 3 &le; d &le; n &le; 10.
Boolean Functions with Five Controllable Cryptographic Properties
Authors: Pantelimon Stănică, Soo Hak Sung
Venue: Designs, Codes and Cryptography (2004)

The strict avalanche criterion (SAC) was introduced by Webster and Tavares [10] in a study of cryptographic design criteria. This is an indicator for local property. In order to improve the global analysis of cryptographically strong functions, Zhang and Zheng [11] introduced the global avalanche characteristics (GAC). The sum-of-squares indicator related to the GAC is defined as &sigma;f&equals;&sum;v&Delta;f2(v), where &Delta;f(v)&equals;&sum;x (&minus;1)f(x)&oplus;f(x}&oplus; v). In this paper, we give a few methods to construct Boolean functions controlling five good cryptographic properties, namely balancedness, good local and GAC, high nonlinearity and high algebraic degree. We improve upon the results of Stanica [8] and Zhang and Zheng [11].
Learning in ERP Contracting: A Principal-Agent Analysis
Authors: D. J. Wu, Min Ding, Lorin M. Hitt
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 8 - Volume 8 (2004)

We examine IT contracting in one particular segment of the IT outsourcing market - the market for large scale packaged software implementations such as Enterprise Resource Planning (ERP) systems. Using a small sample of actual outsourcing contracts in several industries and a review of the relevant outsourcing literature, we determined the common provisions and structural characteristics of these contracts. We then used this description to develop an analytical model of IT outsourcing, using principal agent techniques. Our model captures key characteristics of these IT contracts including a multi-stage project structure, vendor learning, probabilistic binary outcomes (success/failure), use of incentive contracting, and implementation risks. In addition to deriving the optimal IT contract; we specifically focus on how vendor learning affects the optimal structure of the contract. In particular, we find that with rapid vendor learning at the early stage of the contract, it is often more efficient to use a multistage contracting procedure, even if it is not technically required, as this enables strongerincentives to be given to the vendor and creates greater profit and surplus.
A General Model for Finite-Sample Effects in Training and Testing of Competing Classifiers
Authors: Sergey V. Beiden, Marcus A. Maloof, Robert F. Wagner
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

Abstract--The conventional wisdom in the field of statistical pattern recognition (SPR) is that the size of the finite test sample dominates the variance in the assessment of the performance of a classical or neural classifier. The present work shows that this result has only narrow applicability. In particular, when competing algorithms are compared, the finite training sample more commonly dominates this uncertainty. This general problem in SPR is analyzed using a formal structure recently developed for multivariate random-effects receiver operating characteristic (ROC) analysis. Monte Carlo trials within the general model are used to explore the detailed statistical structure of several representative problems in the subfield of computer-aided diagnosis in medicine. The scaling laws between variance of accuracy measures and number of training samples and number of test samples are investigated and found to be comparable to those discussed in the classic text of Fukunaga, but important interaction terms have been neglected by previous authors. Finally, the importance of the contribution of finite trainers to the uncertainties argues for some form of bootstrap analysis to sample that uncertainty. The leading contemporary candidate is an extension of the 0.632 bootstrap and associated error analysis, as opposed to the more commonly used cross-validation.
Non-word identification or spell checking without a dictionary
Authors: Donald C. Comeau, W. John Wilbur
Venue: Journal of the American Society for Information Science and Technology (2004)

MEDLINE® is a collection of more than 12 million references and abstracts covering recent life science literature. With its continued growth and cutting-edge terminology, spell-checking with a traditional lexicon based approach requires significant additional manual followup. In this work, an internal corpus based context quality rating α, frequency, and simple misspelling transformations are used to rank words from most likely to be misspellings to least likely. Eleven-point average precisions of 0.891 have been achieved within a class of 42,340 all alphabetic words having an α score less than 10. Our models predict that 16,274 or 38% of these words are misspellings. Based on test data, this result has a recall of 79% and a precision of 86%. In other words, spell checking can be done by statistics instead of with a dictionary. As an application we examine the time history of low α words in MEDLINE® titles and abstracts.
Extending Gal-Chen and Somerville terrain-following coordinate transformation on time-dependent curvilinear boundaries
Authors: Nils P. Wedi, Piotr K. Smolarkiewicz
Venue: Journal of Computational Physics (2004)

The classical terrain-following coordinate transformation of Gal-Chen and Somerville has been extended to a broad class of time-dependent vertical domains. We provide explicit formulae for the associated transformation coefficients which are readily applicable to numerical implementations. The proposed extension facilitates modeling of undulating boundaries in various areas of computational fluid dynamics. The implementation is discussed in the context of a nonhydrostatic anelastic model for simulations of atmospheric and oceanic flows. The theoretical development is illustrated with numerical simulations of idealized flows. We also discuss an example of a practical application which incorporates a long-wave-approximation for a finite-amplitude free-surface upper boundary, directly relevant to ocean models.
A volumetric approach for interactive 3D modeling
Authors: Dragan Tubic, Patrick Hébert, Denis Laurendeau
Venue: Computer Vision and Image Understanding (2003)

Range image registration and surface reconstruction have been traditionally considered as two independent processes where the latter relies on the results of the former. This paper presents a new approach to surface recovery from range images where the two processes are unified and performed in a common volumetric representation. While the reconstructed surface is described in its implicit form as a signed distance field within a volume, registration information for matching partial surfaces is encoded in the same volume as the gradient of the distance field. This allows coupling of both reconstruction and registration and leads to an algorithm whose complexity is linear with respect to the number of images and the number of measured 3D points. The close integration and performance gain improve interactivity in the process of modeling from range image acquisition to surface reconstruction. The distances computed in the direction of filtered normals improve robustness while preserving the sharp details of the initial range images. It is shown that the integrated algorithm is tolerant to initial registration errors as well as to measurement errors. The paper describes the representation and formalizes the approach. Experimental results demonstrate performance advantages and tolerance to aforementioned types of errors.
Comparison of DSP, RISC and transputer based systems for real time digital control implementation
Authors: D. N. Ramos-Hernandez, M. O. Tokhi
Venue: Systems Analysis Modelling Simulation (2003)

An investigation into the performance evaluation of sequential and parallel computing has been carried out. Performance metrics, on the basis of maximum efficiency, have been proposed for parallel architectures. These apply to both homogeneous and heterogeneous architectures and are consistent with those of traditional architectures. These have been verified through implementation of several algorithms on uni- and multi-processor architectures. Based on the proposed concept of speedup a task allocation strategy for heterogeneous architectures has been developed. It has been demonstrated that, with such a strategy, the efficiency achieved with a heterogeneous architecture is near to its maximum value.Moreover, it has been shown that to achieve maximum efficiency a large proportion of tasks must be allocated to the faster processor of the architecture. However, due to the disparity in capabilities of the processors, communication overhead becomes a dominant factor in the implementation. Thus, to obtain a better task allocation and minimum communication overhead, high performance processors must be selected carefully.Compiler efficiency and code optimisation have been investigated showing that these affect the performance of the processors in real-time applications. The code optimisation experiments have also shown that the regularity or irregularity of the algorithm, as well as the code itself affect the performance of the processor.It has accordingly been demonstrated that different processor capabilities, communication overhead and an inappropriate task allocation can affect dramatically the performance of the application. On the other hand, a poor performance of the processor can result due to the regularity or irregularity of the application, compiler and optimisation levels of the compiler. The applications considered have varying computing requirements due to their different characteristics and different sizes. The heterogeneity present in these architectures helps to satisfy the different computing requirements of the applications.
Concerns and solutions on electronic voting systems adoption
Authors: Yurong Yao, Edward Watson
Venue: Managing IT in government business & communities (2003)

Electronic voting has become a viable form of e-government due to the rapid advances in technologies and communication networks. The United States and most European and Asian Countries, like Japan, have taken the first step towards electronic elections. The unique features of electronic voting systems bring advantages to the public as well as resulting in concerns about electronic voting system (EVS) implementation. In this chapter, we examine those advantages of EVS and the principal obstacles in its implementation: privacy, security and accessibility. By investigating the current technology and government efforts to overcome these problems, some recommendations are proposed to gain voters' trust on EVS and further increase their participation by using EVS.
Measuring Knowledge Management Effectiveness in Communities of Practice
Authors: Martin Smits, Aldo de Moor
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 8 - Volume 8 (2004)

This paper outlines an approach to determine key performance indicators and metrics for knowledge management (KM) in communities of practice. The approach is based on analysis of the KM literature on (i) types of knowledge, (ii) processes of knowledge development and social learning, and (iii) metrics for KM, such as from the Intellectual Capital Method. To embed communities of practice and KM processes in an organizational context, we introduce our Knowledge Governance Framework, which combines knowledge resources, KM, and organizational objectives. Our first hypothesis is that successful KM in organizations requires the linking of knowledge resources to organizational objectives. Our second hypothesis is that a precondition for successful KM is that explicit, quantitative indicators are used. We tested the framework in a small organization in the financial industry. According to our first case experience, the model can be applied in a business setting and our first hypothesis is supported: successful KM links knowledge resources to company objectives . Our second hypothesis is not supported: KM in the case is not based on explicit and quantitative indicators.
Directory requirements for a multidatabase service
Authors: P. Martin, M. Bauer, N. Coburn, P. Larson, G. Neufeld, J. Pach, J. Slonim
Venue: Proceedings of the 1992 conference of the Centre for Advanced Studies on Collaborative research - Volume 2 (1992)

The Directory Service and the Multidatabase Service are two important components of the execution environment for distributed applications being developed within CORDS. We believe that a strong relationship should exist between these two services and discuss a possible architecture in which the catalog for the multidatabase service (the MDBS Catalog) is kept within the directory service. We describe the requirements of the MDBS Catalog: expected contents, expected types and frequencies of access, security, and performance. We discuss how these requirements can be met by the directory service.
Cascaded ATN grammars
Authors: William A. Woods
Venue: Computational Linguistics (1980)

A generalization of the notion of ATN grammar, called a cascaded ATN (CATN), is presented. CATN's permit a decomposition of complex language understanding behavior into a sequence of cooperating ATN's with separate domains of responsibility, where each stage (called an ATN transducer) takes its input from the output of the previous stage. The paper includes an extensive discussion of the principle of factoring -- conceptual factoring reduces the number of places that a given fact needs to be represented in a grammar, and hypothesis factoring reduces the number of distinct hypotheses that have to be considered during parsing.
Illumination-robust face recognition
Authors: Aziz Umit Batur
Venue:  (2003)

The performance of a face recognition system is closely related to the amount of variation observed in face images. Illumination is a major source of such variations; therefore, compensating for illumination changes is a major requirement for face recognition algorithms. In this thesis, we approach the problem of face recognition by putting illumination compensation to the center of our framework. We describe an illumination-robust face recognition system that can recognize near-frontal human faces with changing facial expressions. We start developing our approach by first considering the problem of face recognition under varying illuminations with neutral facial expressions and frontal head poses. We develop a Segmented Linear Subspace algorithm that applies a collection of linear subspaces to a segmented image to achieve reliable recognition under varying illumination. We later relax the constraint on the facial expressions by carrying the Segmented Linear Subspace algorithm into the framework of the shape and texture representation. This representation is based on separating the face image into separate shape and texture vectors. We use the Segmented Linear Subspaces to model the texture component of this representation, which provides us robustness to varying facial expressions since the textures are normalized for shape changes. Computation of the shape and texture representation requires locating a number of facial features on the face image automatically, which is in general a difficult task. It is particularly challenging in our case because of the large illumination changes. To address this problem, we propose an Adaptive Active Appearance Model algorithm, which provides a fast and accurate way of locating landmark points on face images. We combine the Segmented Linear Subspace model and the Adaptive Active Appearance Model algorithm into a single system where we compensate for illumination and facial expression changes in a combined framework.
Teaching Java: using an object-oriented database and the BlueJ IDE
Authors: James H. Paterson, John Haddow
Venue: Proceedings of the 8th annual conference on Innovation and technology in computer science education (2003)

In this Tip we describe the use of a simple Object Oriented database system to implement object persistence in Java programming projects.
Detection or Isolation of Defects? An Experimental Comparison of Unit Testing and Code Inspection
Authors: Per Runeson, Anneliese Andrews
Venue: Proceedings of the 14th International Symposium on Software Reliability Engineering (2003)

Code inspections and white-box testing have both beenused for unit testing. One is a static analysis technique, theother a dynamic one, since it is based on executing testcases. Naturally, the question arises whether one is superiorto the other, or, whether either technique is bettersuited to detect or isolate certain types of defects. We investigatedthis question with an experiment with a focus ondetection of the defects (failures) and isolation of theunderlying sources of the defects (faults). The results indicatethat there exist significant differences for some of theeffects of using code inspection versus testing. White-boxtesting is more effective, i.e. detects significantly moredefects while inspection isolates the underlying source of alarger share of the defects detected. Testers spend significantlymore time, hence the difference in efficiency issmaller, and is not statistically significant. The two techniquesare also shown to detect and identify differentdefects, hence motivating the use of a combination of methods.
Revisiting the &#x00B5;-basis of a rational ruled surface
Authors: Falai Chen, Wenping Wang
Venue: Journal of Symbolic Computation (2003)

The µ-basis of a rational ruled surface P(s,t) = P0(s) + tP1(s) is defined in Chen et al. (Comput. Aided Geom. Design 18 (2001) 61) to consist of two polynomials p(x, y, z, s) and q(x, y, z, s) that are linear in x, y, z. It is shown there that the resultant of p and q with respect to s gives the implicit equation of the rational ruled surface; however, the parametric equation P(s, t) of the rational ruled surface cannot be recovered from p and q. Furthermore, the µ-basis thus defined for a rational ruled surface does not possess many nice properties that hold for the µ-basis of a rational planar curve (Comput. Aided Geom. Design 18 (1998) 803). In this paper, we introduce another polynomial r(x, y, z, s, t) that is linear in x, y, z and t such that p, q, r can be used to recover the parametric equation P(s, t) of the rational ruled surface; hence, we redefine the µ-basis to consist of the three polynomials p, q, r. We present an efficient algorithm for computing the newly-defined µ-basis, and derive some of its properties. In particular, we show that the new µ-basis serves as a basis for both the moving plane module and the moving plane ideal corresponding to the rational ruled surface.
Paper augmented digital documents
Authors: François Guimbretière
Venue: Proceedings of the 16th annual ACM symposium on User interface software and technology (2003)

Paper Augmented Digital Documents (PADDs) are digital documents that can be manipulated either on a computer screen or on paper. PADDs, and the infrastructure supporting them, can be seen as a bridge between the digital and the paper worlds. As digital documents, PADDs are easy to edit, distribute and archive; as paper documents, PADDs are easy to navigate, annotate and well accepted in social settings. The chimeric nature of PADDs make them well suited for many tasks such as proofreading, editing, and annotation of large format document like blueprints.We are presenting an architecture which supports the seamless manipulation of PADDs using today's technologies and reports on the lessons we learned while implementing the first PADD system.