ppxscal/embedding_network huggingface dataset:
Learning functions represented as multiplicity automata
Authors: Amos Beimel, Francesco Bergadano, Nader H. Bshouty, Eyal Kushilevitz, Stefano Varricchio
Venue: Journal of the ACM (JACM) (2000)

We study the learnability of multiplicity automata in Angluin's exact learning model, and we investigate its applications. Our starting point is a known theorem from automata theory relating the number of states in a minimal multiplicity automaton for a function to the rank of its Hankel matrix. With this theorem in hand, we present a new simple algorithm for learning multiplicity automata with improved time and query complexity, and we prove the learnability of various concept classes. These include (among others): -The class of disjoint DNF, and more generally satisfy-O(1) DNF. -The class of polynomials over finite fields. -The class of bounded-degree polynomials over infinite fields. -The class of XOR of terms. -Certain classes of boxes in high dimensions. In addition, we obtain the best query complexity for several classes known to be learnable by other methods such as decision trees and polynomials over GF(2). While multiplicity automata are shown to be useful to prove the learnability of some subclasses of DNF formulae and various other classes, we study the limitations of this method. We prove that this method cannot be used to resolve the learnability of some other open problems such as the learnability of general DNF formulas or even k-term DNF for k = &ohgr;(log n) or satisfy-s DNF formulas for s = &ohgr;(1). These results are proven by exhibiting functions in the above classes that require multiplicity automata with super-polynomial number of states.
Modeling industrial embedded systems with UML
Authors: João M. Fernandes, Ricardo J. Machado, Henrique D. Santos
Venue: Proceedings of the eighth international workshop on Hardware/software codesign (2000)

The main purpose of this paper is to present how the Unified Modeling Language (UML) can be used for modeling industrial embedded systems. By using a car radios production line as a running example, the paper demonstrates the modeling process that can be followed during the analysis phase of complex control applications. In order to guarantee the continuity mapping of the models, the authors propose some guidelines to transform the use case diagrams into a single object diagram, which is one of the main diagrams for the next development phases.
The Incomplete Factorization Multigraph Algorithm
Authors: Randolph E. Bank, R. Kent Smith
Venue: SIAM Journal on Scientific Computing (1999)

We present a new family of multigraph algorithms, ILU-MG, based upon an incomplete sparse matrix factorization using a particular ordering and allowing a limited amount of fill-in. While much of the motivation for multigraph comes from multigrid ideas, ILU-MG is distinctly different from algebraic multilevel methods. The graph of the sparse matrix A is recursively coarsened by eliminating vertices using a graph model similar to Gaussian elimination. Incomplete factorizations are obtained by allowing only the fill-in generated by the vertex parents associated with each vertex. Multigraph is numerically compared with algebraic multigrid on some examples arising from discretizations of partial differential equations on unstructured grids.
Assessing object-oriented technology skills using an Internet-based system
Authors: Ahmed Seffah, Moncef Bari, Michel Desmarais
Venue: ACM SIGCSE Bulletin (1999)

In this paper, we describe a Web-based system that defines training needs for object-oriented developers by identifying the strong and the weak areas of their knowledge and skills. The system is based on the use of two tools, GAA [8] and UKAT [3], developed at the Computer Research Institute of Montreal (CRIM). UKAT (User Knowledge Assessment Tool) uses a state-of-the-art knowledge assessment method to create a user profile of the proficiency in a subject domain. GAA (Intelligent Guide) is a Web-based training system that uses the UKAT to personalize a training course and facilitate self-learning.
On the Characteristics of Growing Cell Structures (GCS) Neural Network
Authors: Jung-Hua Wang, Wei-Der Sun
Venue: Neural Processing Letters (1999)

In this paper, a self-developing neural network model, namely the Growing Cell Structures (GCS) is characterized. In GCS each node (or cell) is associated with a local resource counter &tau; (t). We show that GCS has the conservation property by which the summation of all resource counters always equalss(1 - &alpha;)/&alpha; , thereby s is the increment added to &tau; (t) of the wining node after each input presentation and &alpha; (0 < &alpha; < 1.0) is the forgetting (i.e., decay) factor applied to &tau; (t) of non-wining nodes. The conservation property provides an insight into how GCS can maximize information entropy. The property is also employed to unveil the chain-reaction effect and race-condition which can greatly influence the performance of GCS. We show that GCS can perform better in terms of equi-probable criterion if the resource counters are decayed by a smaller &alpha;.
Cashing in on Caching: An Architecture for Time-BoundedKnowledge-Based Problem Solving
Authors: Niladri Chatterjee, J. A. Campbell
Venue: Real-Time Systems (1998)

Knowledge-based computing, in general, suffers from an inherent open-endedness that precludes its application in time-bounded domains where an answer must be computed within a stipulated time limit. We examine a two-way improvement of the shortcomings: a knowledge representation scheme that provides easy access to relevant knowledge and thereby reduces search time, and a reasoning scheme that is algorithmic in nature and thus makes computational requirements meaningfully estimable. In this work, we offer a cache-based architecture that is capable of both storing knowledge in different formats (e.g. rules, cases), and invoking an appropriate reasoning scheme to fit the available computing time. The cache helps in retrieving the most relevant pieces of knowledge (not only exact matches) required for solving a given problem. This cache relies on a reasoning tactic, knowledge interpolation, that can generate a solution from two near-matches in an algorithmic way, to generate time-bounded solutions. We illustrate the design of such a cache for solving resource allocation problems in the domain of shortwave radio transmission and evaluate its performance in observing imposed temporal bounds.
CGW founder shares his experiences
Authors: Randall Stickrod Carl Machover
Venue: ACM SIGGRAPH Computer Graphics (1998)

One of the intentions of this column is to let you share the experiences of some of the computer graphics Pioneers. This month, we are most fortunate to present the following column from a friend --- and one of our industry's "movers and shakers" --- Randy Stickrod, whom many of you will recognize from his days at Computer Graphics World magazine (CGW). Enjoy!
Speculative Memory Cloaking and Bypassing
Authors: Andreas Moshovos, Gurindar S. Sohi
Venue: International Journal of Parallel Programming (1999)

We revisit memory hierarchy design viewing memory as an inter-operation communication mechanism. We show how dynamically collected information about inter-operation memory communication can be used to improve memory latency. We propose two techniques: (1) Speculative Memory Cloaking, and (2) Speculative Memory Bypassing. In the first technique, we use memory dependence prediction to speculatively identify dependent loads and stores early in the pipeline. These instructions may then communicate prior to address calculation and disambiguation via a fast communication mechanism. In the second technique, we use memory dependence prediction to speculatively transform DEF-store-load-USE dependence chains within the instruction window into DEF-USE ones. As a result, dependent stores and loads are taken off the communication path resulting in further reduction in communication latency. Experimental analysis shows that our methods, on the average, correctly handle 40% (integer) and 19% (floating point) of all memory loads. Moreover, our techniques result in performance improvements of 4.28% (integer) and 3.20% (floating point) over a highly aggressive, dynamically scheduled processor implementing naive memory dependence speculation. We also study the value and address locality characteristics of the values our methods correctly handle. We demonstrate that our methods are orthogonal to both address and value prediction.
A comparative study of computer conferencing and face-to-face communications in systems design
Authors: Mary Sumner, Dennis Hostetler
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

The purpose of this study was to investigate the use of computer conferencing and face-to-face communications to support the work of student teams in a systems analysis project. The study compares the differences in decision quality associated with the projects accomplished by these teams, such team's confidence in the group decision, and each team's satisfaction with the overall decision process. The research questions were: (1) Will the computer conferencing groups produce solutions of higher decision quality, as measured by group scores for decision quality, analytical strength, technical strength, research base for drawing conclusions, and the effectiveness of the group presentation; and (2) Will the face-to-face groups feel greater confidence in the group decision and greater satisfaction with the group decision process, because of the personal relationships that have been developed, as measured by confidence in the group decision, satisfaction with the group decision process, and peer evaluations of participation of their teammates and effectiveness of their teammates. Based upon the findings, computer conferencing afforded opportunities for handling evaluative tasks more effectively than face-to-face meetings. Computer conferencing offers the benefits of producing better decisions because of broader participation, expression of a wider range of opinions, and greater analysis. Computer conferencing can lower time pressures and create the psychological distance among participants needed to engage in more open, candid exchanges of opinions. Its shortcomings are the time it takes to exchange messages, the increased difficulty of coordinating and clarifying ideas, and the increased time it takes to develop a consensus and to arrive at a decision.
XMill: an efficient compressor for XML data
Authors: Hartmut Liefke, Dan Suciu
Venue: ACM SIGMOD Record (2000)

We describe a tool for compressing XML data, with applications in data exchange and archiving, which usually achieves about twice the compression ratio of gzip at roughly the same speed. The compressor, called XMill, incorporates and combines existing compressors in order to apply them to heterogeneous XML data: it uses zlib, the library function for gzip, a collection of datatype specific compressors for simple data types, and, possibly, user defined compressors for application specific data types.
Geometric Constructions in the Digital Plane
Authors: Peter Veelaert
Venue: Journal of Mathematical Imaging and Vision (1999)

We adapt several important properties from affine geometry so that they become applicable in the digital plane. Each affine property is first reformulated as a property about line transversals. Known results about transversals are then used to derive Helly type theorems for the digital plane. The main characteristic of a Helly type theorem is that it expresses a relation holding for a collection of geometric objects in terms of simpler relations holding for some of the subcollections. For example, we show that in the digital plane a collection of digital lines is parallel if and only if each of its 2-membered subcollections consists of two parallel digital lines. The derived Helly type theorems lead to many applications in digital image processing. For example, they provide an appropriate setting for verifying whether lines detected in a digital image satisfy the constraints imposed by a perspective projection. The results can be extended to higher dimensions or to other geometric systems, such as projective geometry.
On a Class of Preconditioning Methods for Dense Linear Systems from Boundary Elements
Authors: Ke Chen
Venue: SIAM Journal on Scientific Computing (1998)

In this paper we discuss several sparse-matrix-based preconditioners suitable for preconditioning dense linear systems of boundary element equations. All preconditioners involve only O(n) nonzeros. We provide a framework for constructing operator-splitting-based preconditioners and use it to analyze a class of sparse preconditioners. For singular integral equations, a more efficient preconditioner is proposed that has a band-2 structure.
Sequential Regularization Methods for Simulating Mechanical Systems with Many Closed Loops
Authors: Uri Ascher, Ping Lin
Venue: SIAM Journal on Scientific Computing (1999)

The numerical simulation problem of large multibody systems has often been treated in two separate stages: (i) the forward dynamics problem for computing system accelerations from given force functions and constraints and (ii) the numerical integration problem for advancing the state in time. For the forward dynamics problem, algorithms have been given with optimal, linear complexity in the number of bodies, in case the system topology does not contain many closed loops.But the interaction between these two stages can be important. Using explicit time integration schemes, we propose a sequential regularization method (SRM) that has a linear complexity in the number of bodies per time step, even in the presence of many closed loops. The method also handles certain types of constraint singularity.
Reconstructing a three-dimensional model with arbitrary errors
Authors: Bonnie Berger, Jon Kleinberg, Tom Leighton
Venue: Journal of the ACM (JACM) (1999)

A number of current technologies allow for the determination of interatomic distance information in structures such as proteins and RNA. Thus, the reconstruction of a three-dimensional set of points using information about its interpoint distances has become a task of basic importance in determining molecular structure. The distance measurements one obtains from techniques such as NMR are typically sparse and error-prone, greatly complicating the reconstruction task. Many of these errors result in distance measurements that can be safely assumed to lie within certain fixed tolerances. But a number of sources of systematic error in these experiments lead to inaccuracies in the data that are very hard to quantify; in effect, one must treat certain entries of the measured distance matrix as being arbitrarily &ldquo;corrupted.&rdquo;The existence of arbitrary errors leads to an interesting sort of error-correction problem&mdash;how many corrupted entries in a distance matrix can be efficiently corrected to produce a consistent three-dimensional structure? For the case of an n &times; n matrix in which every entry is specified, we provide a randomized algorithm running in time O(n log n) that enumerates all structures consistent with at most (1/2-&egr;)n errors per row, with high probability. In the case of randomly located errors, we can correct errors of the same density in a sparse matrix-one in which only a &bgr; fraction of the entries in each row are given, for any constant &bgr;gt;0.
To Ada or not to Ada: Adaing vs. Javaing in real-time systems
Authors: Luís Miguel Pinho, Francisco Vasques
Venue: ACM SIGAda Ada Letters (1999)

Ada is really an unfortunate Lady. After years fighting against C/C++ villains, her major lift-up (Ada 95) had brought up a promise of fortune. However, a new strong villain (Java) has appeared trying to end her struggle for survival.Ada has now to fight with her own weapons. She will only prosper by her own merits. But two questions emerge. Do they exist? Are they better than Java's? Our opinion is that they do exist, and are not matched by any other programming language.
Calibrating a Structured Light Stripe System: A Novel Approach
Authors: D. Q. Huynh, R. A. Owens, P. E. Hartmann
Venue: International Journal of Computer Vision (1999)

The problem associated with calibrating a structured light stripe system is that known world points on the calibration target do not normally fall onto every light stripe plane illuminated from the projector. We present in this paper a novel calibration method that employs the invariance of the cross ratio to overcome this problem. Using 4 known non-coplanar sets of 3 collinear world points and with no prior knowledge of the perspective projection matrix of the camera, we show that world points lying on each light stripe plane can be computed. Furthermore, by incorporating the homography between the light stripe and image planes, the 4 &times; 3 image-to-world transformation matrix for each stripe plane can also be recovered. The experiments conducted suggest that this novel calibration method is robust, economical, and is applicable to many dense shape reconstruction tasks.
A decision-theoretic approach to database selection in networked IR
Authors: Norbert Fuhr
Venue: ACM Transactions on Information Systems (TOIS) (1999)

In networked IR, a client submits a query to a broker, which is in contact with a large number of databases. In order to yield a maximum number of documents at minimum cost, the broker has to make estimates about the retrieval cost of each database, and then decide for each database whether or not to use it for the current query, and if, how many documents to retrieve from it. For this purpose, we develop a general decision-theoretic model and discuss different cost structures. Besides cost for retrieving relevant versus nonrelevant documents, we consider the following parameters for each database: expected retrieval quality, expected number of relevant documents in the database and cost factors for query processing and document delivery. For computing the overall optimum, a divide-and-conquer algorithm is given. If there are several brokers knowing different databases, a preselection of brokers can only be performed heuristically, but the computation of the optimum can be done similarily to the single-broker case. In addition, we derive a formula which estimates the number of relevant documents in a database based on dictionary information.
Approximating Minimum Subset Feedback Sets in Undirected Graphs with Applications
Authors: Guy Even
Venue: SIAM Journal on Discrete Mathematics (2000)

Let G=(V,E) be a weighted undirected graph where all weights are at least one. We consider the following generalization of feedback set problems. Let $S \subset V$ be a subset of the vertices. A cycle is called interesting if it intersects the set S. A subset feedback edge (vertex) set is a subset of the edges (vertices) that intersects all interesting cycles. In minimum subset feedback problems the goal is to find such sets of minimum weight. This problem has a variety of applications, among them genetic linkage analysis and circuit testing. The case in which S consists of a single vertex is equivalent to the multiway cut problem, in which the goal is to separate a given set of terminals. Hence, the subset feedback problem is NP-complete and also generalizes the multiway cut problem. We provide a polynomial time algorithm for approximating the subset feedback edge set problem that achieves an approximation factor of two. This implies a $\Delta$-approximation algorithm for the subset feedback vertex set problem, where $\Delta$ is the maximum degree in G. We also consider the multicut problem and show how to achieve an $O(\log \tau^*)$ approximation factor for this problem, where $\tau^*$ is the value of the optimal fractional solution. To achieve the $O(\log \tau^*)$ factor we employ a bootstrapping technique.
Social, individual and technological issues for groupware calendar systems
Authors: Leysia Palen
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Designing and deploying groupware is difficult. Groupware evaluation and design are often approached from a single perspective, with a technologically-, individually-, or socially-centered focus. A study of Groupware Calendar Systems (GCSs) highlights the need for a synthesis of these multiple perspectives to fully understand the adoption challenges these systems face. First, GCSs often replace existing calendar artifacts, which can impact users calendaring habits and in turn influence technology adoption decisions. Second, electronic calendars have the potential to easily share contextualized information publicly over the computer network, creating opportunities for peer judgment about time allocation and raising concerns about privacy regulation. However, this situation may also support coordination by allowing others to make useful inferences about ones schedule. Third, the technology and the social environment are in a reciprocal, co-evolutionary relationship: the use context is affected by the constraints and affordances of the technology, and the technology also co-adapts to the environment in important ways. Finally, GCSs, despite being below the horizon of everyday notice, can affect the nature of temporal coordination beyond the expected meeting scheduling practice.
Structured Backward Error and Condition of Generalized Eigenvalue Problems
Authors: Desmond J. Higham, Nicholas J. Higham
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

Backward errors and condition numbers are defined and evaluated for eigenvalues and eigenvectors of generalized eigenvalue problems. Both normwise and componentwise measures are used. Unstructured problems are considered first, and then the basic definitions are extended so that linear structure in the coefficient matrices (for example, Hermitian, Toeplitz, Hamiltonian, or band structure) is preserved by the perturbations.
On the Analysis of Finite Volume Methods for Evolutionary Problems
Authors: K. W. Morton
Venue: SIAM Journal on Numerical Analysis (1998)

Finite volume or finite element methods now dominate the modeling of steady flows because of their natural handling of complex configurations. They should have a similar advantage for unsteady flows; however, their error analysis on nonuniform meshes has met a number of difficulties. In this paper a new approach is adopted which makes greater use of a Godunov formulation. It opens the way for a fuller comparison of characteristic-based methods with semidiscrete methods.
Incremental Gradient Algorithms with Stepsizes Bounded Away from Zero
Authors: M. V. Solodov
Venue: Computational Optimization and Applications (1998)

We consider the class of incremental gradient methods for minimizing a sum of continuously differentiable functions. An important novel feature of our analysis is that the stepsizes are kept bounded away from zero. We derive the first convergence results of any kind for this computationally important case. In particular, we show that a certain &epsiv;-approximate solution can be obtained and establish the linear dependence of &epsiv; on the stepsize limit. Incremental gradient methods are particularly well-suited for large neural network training problems where obtaining an approximate solution is typically sufficient and is often preferable to computing an exact solution. Thus, in the context of neural networks, the approach presented here is related to the principle of tolerant training. Our results justify numerous stepsize rules that were derived on the basis of extensive numerical experimentation but for which no theoretical analysis was previously available. In addition, convergence to (exact) stationary points is established when the gradient satisfies a certain growth property.