ppxscal/embedding_network huggingface dataset:
Dynamic Programming for Detecting, Tracking, and Matching Deformable Contours
Authors: Davi Geiger, Alok Gupta, Luiz A. Costa, John Vlontzos
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1995)

The problem of segmenting an image into separate regions and tracking them over time is one of the most significant problems in vision. Terzopoulos et al have proposed an approach to detect the contour regions of complex shapes, assuming a user selected initial contour not very far from the desired solution.We propose to further explore the information provided by the user¿s selected points and apply an optimal method to detect contours which allows a segmentation of the image. The method is based on dynamic programming (DP), and applies to a wide variety of shapes. It is exact and not iterative. We also consider a multiscale approach capable of speeding up the algorithm by a factor of 20, although at the expense of losing the guaranteed optimality characteristic.The problem of tracking and matching these contours is addressed. For tracking, the final contour obtained at one frame is sampled and used as initial points for the next frame. Then, the same DP process is applied. For matching, a novel strategy is proposed where the solution is a smooth displacement field in which unmatched regions are allowed while cross vectors are not. The algorithm is again based on DP and the optimal solution is guaranteed.We have demonstrated the algorithms on natural objects in a large spectrum of applications, including interactive segmentation and automatic tracking of the regions of interest in medical images.
State Transition Analysis: A Rule-Based Intrusion Detection Approach
Authors: Koral Ilgun, R. A. Kemmerer, Phillip A. Porras
Venue: IEEE Transactions on Software Engineering (1995)

This paper presents a new approach to representing and detecting computer penetrations in real-time. The approach, called state transition analysis, models penetrations as a series of state changes that lead from an initial secure state to a target compromised state. State transition diagrams, the graphical representation of penetrations, identify precisely the requirements for and the compromise of a penetration and present only the critical events that must occur for the successful completion of the penetration. State transition diagrams are written to correspond to the states of an actual computer system, and these diagrams form the basis of a rule-based expert system for detecting penetrations, called the state transition analysis tool (STAT). The design and implementation of a UNIX-specific prototype of this expert system, called USTAT, is also presented. This prototype provides a further illustration of the overall design and functionality of this intrusion detection approach. Lastly, STAT is compared to the functionality of comparable intrusion detection tools.
Reorganizing split objects
Authors: Hernán Astudillo R.
Venue: ACM SIGPLAN Notices (1996)

Object-based (i.e. classless) models are very effective for elucidating requirements from users, and they support exploratory programming and rapid prototyping, providing a direct manipulation approach. On the other hand, class-based models have powerful mechanisms to control redundancy, exploit sharing, express extension, and propagate changes to instances.The price object-based approaches pay is loss of control over change propagation, and potential redundancy. Two mechanisms to overcome this are sharing among objects and definition of objects as extension of others. We examine these mechanisms, and consider the effect that interacting policies for objects sharing and definition-by-extension have on change propagation and replication control. An implication is that, in absence of meta-objects or extra-language support, monolithic shared parts cannot coexist with prototypes represented as split objects.
WWW interactive learning environments for computer science education
Authors: David Carlson, Mark Guzdial, Colleen Kehoe, Viren Shah, John Stasko
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

The wide accessibility of the World Wide Web makes it a perfect base for developing computer science courseware modules. Since learning involves more than just receiving transmitted information, courseware must be interactive and encourage student engagement, which is a challenge on the Web architecture. This article describes an ongoing effort to develop World Wide Web-based computer science courseware modules that will use interactive components as integral parts of the material, in order to promote student involvement. It also discusses the proposed usage of new technology such as HotJava in this framework.
Model and verification of a data manager based on ARIES
Authors: Dean Kuo
Venue: ACM Transactions on Database Systems (TODS) (1996)

In this article, we model and verify a data manager whose algorithm is based on ARIES. The work uses the I/O automata method as the formal model and the definition of correctness is defined on the interface between the scheduler and the data manager.
On batch means in the simulation and statistics communities
Authors: Michael Sherman
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Batching is a well known technique for estimating the variance of point estimators computed from simulation experiments. The batch statistic variance estimator is simply the (appropriately scaled) sample variance of the estimator computed on subsets of data. The simulation and statistics communities seem to be largely unaware of each other's results in this area. Some empirical and theoretical results from the simulation and statistics literature will be discussed and compared. In particular, we discuss the important issue of selecting batch size and present a new data based method for determining it. The basic idea is to empirically estimate the optimal batch size for a smaller simulation length, and then extrapolate using knowledge of the optimal order of magnitude of batch length for the original simulation length. We provide a small simulation showing the effectiveness of the proposed method.
Matching-based incremental evaluators for hierarchical attribute grammar dialects
Authors: Alan Carle, Lori Pollock
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1995)

Although attribute grammars have been very effective for defining individual modules of language translators, they have been rather ineffective for specifying large program-transformational systems. Recently, several new attribute grammar &ldquo;dialects&rdquo; have been developed that support the modular specification of these systems by allowing modules, each described by an attribute grammar, to be composed to form a complete system. Acceptance of these new hierarchical attribute grammar dialects requires the availability of efficient batch and incremental evaluators for hierarchical specifications. This paper addresses the problem of developing efficient incremental evaluators for hierarchical specifications. A matching-based approach is taken in order to exploit existing optimal change propagation algorithms for nonhierarchical attribute grammars. A sequence of four new matching algorithms is presented, each increasing the number of previously computed attribute values that are made available for reuse during the incremental update.
On the existence of equilibria in noncooperative optimal flow control
Authors: Yannis A. Korilis, Aurel A. Lazar
Venue: Journal of the ACM (JACM) (1995)

The existence of Nash equilibria in noncooperative flow control in a general product-form network shared by K users is investigated. The performance objective of each user is to maximize its average throughput subject to an upper bound on its average time-delay. Previous attempts to study existence of equilibria for this flow control model were not successful, partly because the time-delay constraints couple the strategy spaces of the individual users in a way that does not allow the application of standard equilibrium existence theorems from the game theory literature. To overcome this difficulty, a more general approach to study the existence of Nash equilibria for decentralized control schemes is introduced. This approach is based on directly proving the existence of a fixed point of the best reply correspondence of the underlying game. For the investigated flow control model, the best reply correspondence is shown to be a function, implicitly defined by means of K interdependent linear programs. Employing an appropriate definition for continuity of the set of optimal solutions of parameterized linear programs, it is shown that, under appropriate conditions, the best reply function is continuous. Brouwer's theorem implies, then, that the best reply function has a fixed point.
Compensatory mechanisms in an attractor neural network model of schizophrenia
Authors: D. Horn, E. Ruppin
Venue: Neural Computation (1995)

We investigate the effect of synaptic compensation on the dynamic behavior of an attractor neural network receiving its input stimuli as external fields projecting on the network. It is shown how, in the face of weakened inputs, memory performance may be preserved by strengthening internal synaptic connections and increasing the noise level. Yet, these compensatory changes necessarily have adverse side effects, leading to spontaneous, stimulus-independent retrieval of stored patterns. These results can support Stevens' recent hypothesis that the onset of schizophrenia is associated with frontal synaptic regeneration, occurring subsequent to the degeneration of temporal neurons projecting on these areas.
Collaboratively teaching a multidisciplinary course
Authors: Suzanne Gladfelter
Venue: 3C ON-LINE (1996)

In spring 1996 two colleagues and I collaboratively taught an experimental multidisciplinary introductory-level honors speech communications course. The semester-long 4.5 credit course covered public speaking, presentation software, and philosophical soundness. The course demonstrated to students and faculty how technology can serve the humanities.
The utility of planning
Authors: Shlomo Zilberstein
Venue: ACM SIGART Bulletin (1995)

Evaluation and comparison of existing planning systems is hard because they disagree on the fundamental role of planning, on evaluation metrics, and on the notion of success and failure. This paper suggests a decision-theoretic approach to evaluate planning systems that generalizes the role of planning in intelligent systems. The planner is viewed as a source of information that is used by an execution architecture in order to select actions. A planner is only as good as the effect it has on the performance of an operational system. Our approach calls for a clear separation between the planning component and the execution architecture and for evaluation of planning systems within the context of a well-defined command, planning and execution environment. The evaluation is based on the expected utility of the domain histories that are induced by the planning component.
On a Generalization of a Normal Map and Equation
Authors: Jong-Shi Pang, Jen-Chih Yao
Venue: SIAM Journal on Control and Optimization (1995)

The class of normal maps was recently investigated by Robinson and Ralph in connection with the study of a variational inequality defined on a polyhedral set. In this paper a generalization of such a map is considered, and the associated generalized normal equation is studied. The latter provides a unified formulation of several generalized variational inequality and complementarity problems. Using degree theory, some sufficient conditions for the existence of a zero of a generalized normal map are established and the stability of a generalized normal equation at a solution is analyzed. Specializations of the results to various applications are discussed.
Lower bounds on the VC dimension of smoothly parameterized function classes
Authors: Wee Sun Lee, Peter L. Bartlett, Robert C. Williamson
Venue: Neural Computation (1995)

We examine the relationship between the VC dimension and the number of parameters of a threshold smoothly parameterized function class. We show that the VC dimension of such a function class is at least k if there exists a k-dimensional differentiable manifold in the parameter space such that each member of the manifold corresponds to a different decision boundary. Using this result, we are able to obtain lower bounds on the VC dimension proportional to the number of parameters for several thresholded function classes including two-layer neural networks with certain smooth activation functions and radial basis functions with a gaussian basis. These lower bounds hold even if the magnitudes of the parameters are restricted to be arbitrarily small. In Valiant's probably approximately correct learning framework, this implies that the number of examples necessary for learning these function classes is at least linear in the number of parameters.
Extending SQL-92 for OODB access: design and implementation experience
Authors: Jerry Kiernan, Michael J. Carey
Venue: ACM SIGPLAN Notices (1995)

This paper describes the design and implementation of a query engine that provides extended SQL-based access to the data managed by an object-oriented database system. This query engine allows extended SQL queries to be embedded in C++ programs or issued interactively as from a command line interface. The language supported by the engine is the complete SQL-92 select statement plus object extensions for navigating along paths and embedded structures, querying nested sets, and invoking member functions. In addition, an object-oriented SQL view facility is provided. Using this view facility, one can define object-oriented views; one can also define views that flatten complex OODB schemas, allowing direct access by existing tools designed to provide remote access to relational databases. The view facility also supports the definition of views that include reference and set-valued columns based on other views, thus allowing entire "view schemas" to be created. This paper describes the SQL-92 query and view extensions and discusses a number of issues that arose on the way to the implementation that is currently running on top of the ObjectStore OODB system.
Regularized neural networks: some convergence rate results
Authors: Valentina Corradi, Halbert White
Venue: Neural Computation (1995)

In a recent paper, Poggio and Girosi (1990) proposed a class of neural networks obtained from the theory of regularization. Regularized networks are capable of approximating arbitrarily well any continuous function on a compactum. In this paper we consider in detail the learning problem for the one-dimensional case. We show that in the case of output data observed with noise, regularized networks are capable of learning and approximating (on compacta) elements of certain classes of Sobolev spaces, known as reproducing kernel Hilbert spaces (RKHS), at a nonparametric rate that optimally exploits the smoothness properties of the unknown mapping. In particular we show that the total squared error, given by the sum of the squared bias and the variance, will approach zero at a rate of n(-2m)/(2m+1), where m denotes the order of differentiability of the true unknown function. On the other hand, if the unknown mapping is a continuous function but does not belong to an RKHS, then there still exists a unique regularized solution, but this is no longer guaranteed to converge in mean square to a well-defined limit. Further, even if such a solution converges, the total squared error is bounded away from zero for all n sufficiently large.
An object-oriented simulation of Air Force support equipment usage
Authors: Eric A. Zahn, Nicholas J. Stute, Patrick K. Clark
Venue: Proceedings of the 27th conference on Winter simulation (1995)

The paper summarizes a joint study by the U.S. Air Force and TASC, Inc. that models aerospace support equipment usage during a deployment of fighter aircraft. The model explains the present role of the equipment, and introduces a possible alternative. The main objective of the study, to replace the current support equipment system while maintaining efficiency, is illustrated. The implementation of the model in IMDE, an object-oriented discrete-event simulation package, is then described. The two options are compared; results are displayed showing the number of sorties aborted with each equipment arrangement.
HTGL: a program modelling language
Authors: Carl J. Beckmann
Venue: ACM SIGARCH Computer Architecture News (1995)

This paper describes an abstract language called HTGL used to model the parallel structure and behavior of programs. These abstract models can be used as input to simulators and analysis tools for more accurate simulation than analytic or queueing models, without the unnecessary burden of compiling actual programs. It can also be used as a rapid software prototyping tool, for easily measuring the inherent parallelism in a parallel algorithm prior to actual coding, or for implementing certain compiler optimizations on the simplified data structures of the abstract language. Source code is publicly available and includes a reusable software library.
Randomness-Optimal Unique Element Isolation withApplications to Perfect Matching and Related Problems
Authors: Suresh Chari, Pankaj Rohatgi, Aravind Srinivasan
Venue: SIAM Journal on Computing (1995)

In this paper, we precisely characterize the randomness complexity of the unique element isolation problem, a crucial step in the $RNC$ algorithm for perfect matching due to Mulmuley, Vazirani, and Vazirani [Combinatorica, 7 (1987), pp. 105--113] and in several other applications. Given a set $S$ and an unknown family ${\cal F} \subseteq 2^S$ with $|{\cal F}| \leq Z$, we present a scheme to assign polynomially bounded weights to the elements of $S$, using only $O(\log Z + \log |S|)$ random bits, such that the minimum weight set in $\cal F$ is unique with high probability. This generalizes the solution of Mulmuley, Vazirani, and Vazirani who use $O(S\log S)$ bits, independent of $Z$. We also provide a matching lower bound for the randomness complexity of this problem. The new weight assignment scheme yields a randomness-efficient $RNC^2$ algorithm for perfect matching which uses $O(\log Z + \log n)$ random bits where $Z$ is any given upper bound on the number of perfect matchings in the input graph. This generalizes the result of Grigoriev and Karpinski [Proc. IEEE Symposium on Foundations of Computer Science, 1987, pp. 166--172], who present an $NC^3$ algorithm when $Z$ is polynomial and also improves the running time in this case. The worst-case randomness complexity of our algorithm is $O(n \log(m/n))$ random bits improving on the previous bound of $O(m \log n)$. Our scheme also gives randomness-efficient solutions for several problems where unique element isolation is used, such as $RNC$ algorithms for variants of matching and basic problems on linear matroids. We obtain a randomness-efficient random reduction from $SAT$ to $USAT$, the language of uniquely satisfiable formulas which can be derandomized in the case of languages in $FewP$ to yield new proofs of the results $FewP\subseteq \oplus P$ and $FewP\subseteq C_{\!\!=}P$.
LISA: a tool for automatic language implementation
Authors: Marjan Mernik, Nikolaj Korbar, Viljem Žumer
Venue: ACM SIGPLAN Notices (1995)

In the paper a tool for automatic language implementation is described. From formal language definition LISA1 produces efficient interpreters or compilers in C++. For lexical and syntax analysis well known formal methods: regular expressions and BNF are used. Semantics of the defined language is described with attribute grammars. LISA is a part of the ongoing effort to build an environment that supports experimentation in automatic language implementation for educational and industrial purposes.
Knowledge-based document retrieval in office environments: the Kabiria system
Authors: Augusto Celentano, Maria Grazia Fugini, Silvano Pozzi
Venue: ACM Transactions on Information Systems (TOIS) (1995)

In the office environment, the retrieval of documents is performed using the concepts contained in the documents, information about the procedural context where the documents are used, and information about the regulations and laws that discipline the life of documents within a given application domain. To fulfill the requirements of such a sophisticated retrieval, we propose a document retrieval model and system based on the representation of knowledge describing the semantic contents of documents, the way in which the documents are managed by procedures and by people in the office, and the application domain where the office operates. The article describes the knowledge representation issues needed for the document retrieval system and presents a document retrieval model that captures these issues. The effectiveness of the approach is illustrated by describing a system, named Kabiria, built on top of such model. The article describes the querying and browsing environments, and the architecture of the system.
Fast Parallel Computation of the Polynomial Remainder Sequence Via Bezout and Hankel Matrices
Authors: Dario Bini, Luca Gemignani
Venue: SIAM Journal on Computing (1995)

If $u(x)$ and $v(x)$ are polynomials of degree $n$ and $m$, respectively, $m
An unlevel playing field: women in the introductory computer science courses
Authors: Marian Gunsher Sackrowitz, Ann Parker Parelius
Venue: ACM SIGCSE Bulletin (1996)

This study looks at students in introductory computer science courses at two major universities in order to understand some of the reasons behind the recent sharp decline in the number of female computer science majors. The study focuses on gender differences in preparation and skills and the implications of these differences on success in the introductory course.The study showed that despite the proliferation of computers in many areas of daily life, female students still enter introductory computer science classes with weaker programming skills and less involvement with computers than their male counterparts.Prior familiarity with programming concepts emerged as the most useful predictor of success in the course and a high level of success was difficult to achieve without this prior knowledge. The mean grades were comparable for men and women but the women were underrepresented among the highest achievers.This study suggests that the above factors combine to place women at a disadvantage in introductory computer science classes and that some adjustments to the pace and/or structure of this course might be necessary to attract and retain more women in the major.
Parallel algorithms for forward and back substitution in direct solution of sparse linear systems
Authors: Anshul Gupta, Vipin Kumar
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

A few parallel algorithms for solving triangular systems resulting from parallel factorization of sparse linear systems have been proposed and implemented recently. We present a detailed analysis of parallel complexity and scalability of the best of these algorithms and the results of its implementation on up to 256 processors of the Cray T3D parallel computer. It has been a common belief that parallel sparse triangular solvers are quite unscalable due to a high communication to computation ratio. Our analysis and experiments show that, although not as scalable as the best parallel sparse Cholesky factorization algorithms, parallel sparse triangular solvers can yield reasonable speedups in runtime on hundreds of processors. We also show that for a wide class of problems, the sparse triangular solvers described in this paper are optimal and are asymptotically as scalable as a dense triangular solver.
Open issues in parallel query optimization
Authors: Waqar Hasan, Daniela Florescu, Patrick Valduriez
Venue: ACM SIGMOD Record (1996)

We provide an overview of query processing in parallel database systems and discuss several open issues in the optimization of queries for parallel machines.