ppxscal/embedding_network huggingface dataset:
Optimization of distributed, object-oriented systems (poster session)
Authors: William J. Ray
Venue: Addendum to the 2000 proceedings of the conference on Object-oriented programming, systems, languages, and applications (Addendum) (2000)

Object-Oriented (OO) computing is fast becoming the de-facto standard for software development. Currently, many OO systems consist of a single, large object server and multiple client applications. Optimizations can be accomplished if these large monolithic servers are decomposed into numerous smaller object servers and spread across the network. Matching object servers to network assets isn't a trivial task. The more criteria one considers in determining an optimal assignment, the more complex the processing becomes. Complicating matters is the fact that many of these criteria are not fixed. Optimal deployment strategies for object servers can change given deviations in object servers, client applications, operational missions, hardware modifications, and various other changes to the environment. Once distributed object servers become more prevalent, there will be a need to optimize the deployment of object servers to best serve the end user's changing needs. Having the ability to generate object server deployment strategies would allow users to take full advantage of their network of computers. State of the art load balancing techniques consists of scheduling a given number of independent tasks to a set of machines. Object servers do not have independent tasks. All methods in an object are related. Also, the number of times a method is called is usually dependent on the interaction with the end user. Object servers, client applications, user inputs, and network resources can be profiled. A system of non-linear equations can be derived from these profiles. Solving this system of equations can produce more optimal deployment strategies for the object servers.
An analysis of some time-sharing techniques
Authors: Norman R. Nielsen
Venue: Communications of the ACM (1971)

The effectiveness of certain time-sharing techniques such as program relocation, disk rotational delay minimization, and swap volume minimization is investigated. Summary data is presented, and the findings are discussed. The vehicle for this investigation was a SIMULA based simulation model reflecting an early framework for a planned Burroughs B6500 time-sharing system. Inasmuch as the B6500 system is based upon the use of variable sized segments and a dynamic overlay procedure, data is also presented which provides some indication of the effectiveness of this type of organization in a time-sharing environment. The design characteristics and operational capabilities of the simulation model are also described.
Distance learning through distributed collaborative video viewing
Authors: J. J. Cadiz, Anand Balachandran, Elizabeth Sanocki, Anoop Gupta, Jonathan Grudin, Gavin Jancke
Venue: Proceedings of the 2000 ACM conference on Computer supported cooperative work (2000)

Previous research on Tutored Video Instruction (TVI) shows that learning is enhanced when small groups of students watch and discuss lecture videos together. Using specialized, high-end videoconferencing systems, these improved results have been shown to apply even when the students are in different locations (Distributed TVI, or DTVI). In this paper, we explore two issues in making DTVI-like scenarios widely supported at low cost. First, we explore design of a system that allows distributed individuals to collectively watch video using shared VCR controls such as play, pause, seek, stop. We show how such a system can be built on top of existing commercial technologies. Second, we explore the impact of four alternative discussion channels on student learning and interaction behavior. The four channels-text chat, audioconferencing, videoconferencing, and face-to-face-have differing infrastructure requirements and costs. Our lab studies show that while text chat does not work, there is no significant difference in discussion behavior and learning between audioconferencing and videoconferencing. While lab studies have their limitations and long-term field studies need to be done, the preliminary results point to a low-cost way for a DTVI-like model to be deployed widely in the very near future.
Improving the agent-oriented modeling process by roles
Authors: Ralph Depke, Reiko Heckel, Jochen M. Kuster
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

The agent-oriented modeling process is divided in a typical sequence of activities, i.e., \emph{requirements specification}, \emph{analysis}, and \emph{design}. The \emph{requirements} are specified by descriptions of the system's functionality and by exemplary scenarios of essential interactions. In \emph{analysis} the system's structure is captured and mandatory behavior of agents is prescribed. The \emph{design} model describes system behavior by means of local operations. The problem arises how the transition between these different stages of the modeling process can be performed. In this paper, we introduce a concept of roles in order to support the transition in a systematic way and thereby improving the agent-oriented modeling process.
Constant Number Serial Pipeline Multipliers
Authors: K. Z. Pekmestzi, P. Kalivas
Venue: Journal of VLSI Signal Processing Systems (2000)

The pipeline form of the serial/parallel multiplier for constant numbers, which operates without insertion of zero words between successive data, is presented. The constant number is in Canonical Signed Digit (CSD) form and the other factor in two's complement form. The CSD form was chosen because it yields significant hardware reduction. Also, for the above data forms the Lyon's serial pipeline multiplier is examined. For these designs, a special algorithm for the multiplication of two's complement numbers with constant numbers in CSD representation was developed. The proposed serial pipeline multipliers are compared with the existing schemes from the point of hardware complexity.
A practical tool kit for making portable compilers
Authors: Andrew S. Tanenbaum, Hans van Staveren, E. G. Keizer, Johan W. Stevenson
Venue: Communications of the ACM (1983)

The Amsterdam Compiler Kit is an integrated collection of programs designed to simplify the task of producing portable (cross) compilers and interpreters. For each language to be compiled, a program (called a front end) must be written to translate the source program into a common intermediate code. This intermediate code can be optimized and then either directly interpreted or translated to the assembly language of the desired target machine. The paper describes the various pieces of the tool kit in some detail, as well as discussing the overall strategy.
Domain Decomposition Models for Parallel Monte Carlo Transport
Authors: Henry J. Alme, Garry H. Rodrigue, George B. Zimmerman
Venue: The Journal of Supercomputing (2001)

We present a strategy for parallelizing computations that use the transport method. It combines spatial domain decomposition with domain replication to realize the scaling benefits of replication while allowing for problems whose computational mesh will not fit in a single processor's memory. The mesh is decomposed into a small number of spatial domains&mdash;typically fewer domains than there are processors&mdash;and heuristics are used to estimate the computational effort required to generate the solution in each subdomain using Monte Carlo. That work estimate determines the number of times a subdomain is replicated relative to the others. Timing of runs for two problems show that the new method scales better than traditional domain decomposition.
On the Convergence of Temporal-Difference Learning with Linear Function Approximation
Authors: Vladislav Tadić
Venue: Machine Learning (2001)

The asymptotic properties of temporal-difference learning algorithms with linear function approximation are analyzed in this paper. The analysis is carried out in the context of the approximation of a discounted cost-to-go function associated with an uncontrolled Markov chain with an uncountable finite-dimensional state-space. Under mild conditions, the almost sure convergence of temporal-difference learning algorithms with linear function approximation is established and an upper bound for their asymptotic approximation error is determined. The obtained results are a generalization and extension of the existing results related to the asymptotic behavior of temporal-difference learning. Moreover, they cover cases to which the existing results cannot be applied, while the adopted assumptions seem to be the weakest possible under which the almost sure convergence of temporal-difference learning algorithms is still possible to be demonstrated.
Conversation trees and threaded chats
Authors: Marc Smith, J. J. Cadiz, Byron Burkhalter
Venue: Proceedings of the 2000 ACM conference on Computer supported cooperative work (2000)

Chat programs and instant messaging services are increasingly popular among Internet users. However, basic issues with the interfaces and data structures of most forms of chat limit their utility for use in formal interactions (like group meetings) and decision-making tasks. In this paper, we discuss Threaded Text Chat, a program designed to address some of the deficiencies of current chat programs. Standard forms of chat introduce ambiguity into interaction in a number of ways, most profoundly by rupturing connections between turns and replies. Threaded Chat presents a solution to this problem by supporting the basic turn-taking structure of human conversation. While the solution introduces interface design challenges of its own, usability studies show that users' patterns of interaction in Threaded Chat are equally effective, but different (and possibly more efficient) than standard chat programs.
Stable Spectral Methods on Tetrahedral Elements
Authors: J. S. Hesthaven, C. H. Teng
Venue: SIAM Journal on Scientific Computing (1999)

A framework for the construction of stable spectral methods on arbitrary domains with unstructured grids is presented. Although most of the developments are of a general nature, an emphasis is placed on schemes for the solution of partial differential equations defined on the tetrahedron.In the first part the question of well-behaved multivariate polynomial interpolation on the tetrahedron is addressed, and it is shown how to extend the electrostatic analogy of the Jacobi polynomials to problems beyond the line. This allows for the identification of nodal sets suitable for polynomial interpolation within the tetrahedron and, subsequently, for the formulation of stable spectral schemes on such unstructured nodal sets. The second part of this work is devoted to a discussion of weakly imposed boundary conditions, and energy-stable schemes are formulated for a wide class of problems, exemplified by advection problems, advection-diffusion problems, and linear symmetric hyperbolic systems.Finally, in the third part, issues related to computational efficiency and implementation of the schemes are discussed. The spectral accuracy of the approximation is confirmed through an example, and factorization methods for the efficient computation of derivatives on the general nodal sets within the d-simplex are developed, ensuring that the proposed schemes are competitive with tensor-product-based methods. In this last part we also show that the advective operator results in an ${\cal O}(n^{-2})$ restriction on the time-step, similar to that of spectral collocation methods employing a tensor-product-based approximation. The performance of the proposed scheme is illustrated by solving a wave problem on a triangulated domain, confirming the expected accuracy and stability.
The university perspective: awarding credit for advanced placement (AP) in computer science
Authors: Barbara Boucher Owens, Fran Hunt, Stuart Reges, Cary Laxer
Venue: Proceedings of the thirty-second SIGCSE technical symposium on Computer Science Education (2001)

This panel discusses the granting of credit for AP CS by colleges and universities. Particularly with the change of the AP CS exam from Pascal to C++ last year, this panel is aimed both the collegiate and high school communities who are interested in comments from schools who have experience with AP CS students. Topics will include a short review of the AP curriculum, and some examples of what credit is given, how AP CS students are placed, and how the students perform in those and subsequent courses.
Randomization, speculation, and adaptation in batch schedulers
Authors: Dejan Perkovic, Peter J. Keleher
Venue: Proceedings of the 2000 ACM/IEEE conference on Supercomputing (CDROM) (2000)

This paper proposes extensions to the backfilling job-scheduling algorithm that significantly improve its performance. We introduce variations that sort the "backfilling order" in priority-based and randomized fashions. We examine the effectiveness of guarantees present in conservative backfilling and find that initial guarantees have limited practical value, while the performance of a "no-guarantee" algorithm can be significantly better when combined with extensions that we introduce. Our study differs from many similar studies in using traces that contain user estimates. We find that actual overestimates are large and significantly different from simple models. We propose the use of speculative backfilling and speculative test runs to counteract these large over-estimations. Finally, we explore the impact of dynamic, system-directed adaptation of application parallelism. The cumulative improvements of these techniques decrease the bounded slowdown, our primary metric, to less then 15 percent of conservative backfilling.
DATA-DIAL: two-way communication with computers from ordinary dial telphones
Authors: Thomas Marill, Daniel Edwards, Wallace Feurzeig
Venue: Communications of the ACM (1963)

An operating system is described which allows users to call up a remotely located computer from ordinary dial telephones. No special hardware or connections are required at the users' telephones. Input to the computer is through the telephone dial; output from the computer is in spoken form. Results of a test with telephones in the Boston area are reported.
Depth from Defocus vs. Stereo: How Different Really Are They?
Authors: Yoav Y. Schechner, Nahum Kiryati
Venue: International Journal of Computer Vision (2000)

Depth from Focus (DFF) and Depth from Defocus (DFD) methods are theoretically unified with the geometric triangulation principle. Fundamentally, the depth sensitivities of DFF and DFD are not different than those of stereo (or motion) based systems having the same physical dimensions. Contrary to common belief, DFD does not inherently avoid the matching (correspondence) problem. Basically, DFD and DFF do not avoid the occlusion problem any more than triangulation techniques, but they are more stable in the presence of such disruptions. The fundamental advantage of DFF and DFD methods is the two-dimensionality of the aperture, allowing more robust estimation. We analyze the effect of noise in different spatial frequencies, and derive the optimal changes of the focus settings in DFD. These results elucidate the limitations of methods based on depth of field and provide a foundation for fair performance comparison between DFF/DFD and shape from stereo (or motion) algorithms.
Industry perceptions of the knowledge, skills, and abilities needed by computer programmers
Authors: Janet L. Bailey, Greg Stefaniak
Venue: Proceedings of the 2001 ACM SIGCPR conference on Computer personnel research (2001)

In a day and age where computer information systems permeate virtually every facet of society, organizations find it difficult to hire adequate numbers of computer personnel. Judging by the number of `quick-fix' organizations that offer training in &ldquo;weeks rather than years&rdquo; and the number of individuals that each claims to train per year, the shortage would seem to come from a lack of adequate skills rather than a lack of applicants. This paper reports the findings of an study designed to identify the knowledge, skills, and abilities (KSAs) needed by one group of information technology (IT) personnel &mdash; the computer programmer.
A Note on Preconditioning for Indefinite Linear Systems
Authors: Malcolm F. Murphy, Gene H. Golub, Andrew J. Wathen
Venue: SIAM Journal on Scientific Computing (1999)

Preconditioners are often conceived as approximate inverses. For nonsingular indefinite matrices of saddle-point (or KKT) form, we show how preconditioners incorporating an exact Schur complement lead to preconditioned matrices with exactly two or exactly three distinct eigenvalues. Thus approximations of the Schur complement lead to preconditioners which can be very effective even though they are in no sense approximate inverses.
Measurements of segment size
Authors: Alan Batson, Shy-Ming Ju, David C. Wood
Venue: Communications of the ACM (1970)

Distributions of segment sizes measured under routine operating conditions on a computer system which utilizes variable sized segments (the Burroughs B5500) are discussed. The most striking feature of the measurements is the large number of small segments&mdash;about 60 percent of the segments in use contain less than 40 words. Although the results are certainly not installation independent, and although they are particularly influenced by features of the B5500 ALGOL system, they should be relevant to the design of new computer systems, especially with respect to the organization of paging schemes.
Toward a discipline of real-time programming
Authors: Niklaus Wirth
Venue: Communications of the ACM (1977)

Programming is divided into three major categories with increasing complexity of reasoning in program validation: sequential programming, multiprogramming, and real-time programming. By adhering to a strict programming discipline and by using a suitable high-level language molded after this discipline, the complexity of reasoning about concurrency and execution time constraints may be drastically reduced. This may be the only practical way to make real-time systems analytically verifiable and ultimately reliable. A possible discipline is outlined and expressed in terms of the language Modula.
The Multics virtual memory: concepts and design
Authors: A. Bensoussan, C. T. Clingen, R. C. Daley
Venue: Communications of the ACM (1972)

As experience with use of on-line operating systems has grown, the need to share information among system users has become increasingly apparent. Many contemporary systems permit some degree of sharing. Usually, sharing is accomplished by allowing several users to share data via input and output of information stored in files kept in secondary storage. Through the use of segmentation, however, Multics provides direct hardware addressing by user and system programs of all information, independent of its physical storage location. Information is stored in segments each of which is potentially sharable and carries its own independent attributes of size and access privilege. Here, the design and implementation considerations of segmentation and sharing in Multics are first discussed under the assumption that all information resides in a large, segmented main memory. Since the size of main memory on contemporary systems is rather limited, it is then shown how the Multics software achieves the effect of a large segmented main memory through the use of the Honeywell 645 segmentation and paging hardware.
A Case Against Kruppa's Equations for Camera Self-Calibration
Authors: Peter Sturm
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2000)

We consider the self-calibration problem for perspective cameras and especially the classical Kruppa equation approach. It is known that for several common types of camera motion, self-calibration is degenerate, which manifests itself through the existence of ambiguous solutions. In a previous paper, we have studied these critical motion sequences and have revealed their importance for practical applications. Here, we reveal a type of camera motion that is not critical for the generic self-calibration problem, but for which the Kruppa equation approach fails. This is the case if the optical centers of all cameras lie on a sphere and if the optical axes pass through the sphere's center, a very natural situation for 3D object modeling from images. Results of simulated experiments demonstrate the instability of numerical self-calibration algorithms in near-degenerate configurations.
On propagation of equational constraints in CAD-based quantifier elimination
Authors: Scott McCallum
Venue: Proceedings of the 2001 international symposium on Symbolic and algebraic computation (2001)

Collins [4] observed that quantifier elimination problems often have equational constraints, and he asserted that such constraints can be used to reduce the projection sets required for cylindrical algebraic decomposition (cad) based quantifier elimination. This paper follows on from [11], and validates the use of a semi-restricted equational projection scheme throughout the projection phase of cad. The fully restricted projection scheme as originally proposed in [4] is proved valid for four variable problems under certain conditions.
Computing blocking probabilities in multiclass wavelength routing networks
Authors: Sridhar Ramesh, George N. Rouskas, Harry G. Perros
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (2000)

We present an approximate analytical method to evaluate efficiently and accurately the call blocking probabilities in wavelength routing networks with multiple classes of calls. The model is fairly general and allows each source-destination pair to service calls of different classes, with each call occupying one wavelength per link. Our approximate analytical approach involves two steps. The arrival process of calls on some routes is first modified slightly to obtain an approximate multiclass network model. Next, all classes of calls on a particular route are aggregated to give an equivalent single-class model. Thus, path decomposition algorithms for single-class wavelength routing networks may be readily extended to the multiclass case. This article is a first step towards understanding the issues arising in wavelength routing networks that serve multiple classes of customers.
Sensitivity Analysis for Decision Boundaries
Authors: A. P. Engelbrecht
Venue: Neural Processing Letters (1999)

A novel approach is presented to visualize and analyze decision boundaries for feedforward neural networks. First order sensitivity analysis of the neural network output function with respect to input perturbations is used to visualize the position of decision boundaries over input space. Similarly, sensitivity analysis of each hidden unit activation function reveals which boundary is implemented by which hidden unit. The paper shows how these sensitivity analysis models can be used to better understand the data being modelled, and to visually identify irrelevant input and hidden units.
A Trainable System for Object Detection
Authors: Constantine Papageorgiou, Tomaso Poggio
Venue: International Journal of Computer Vision (2000)

This paper presents a general, trainable system for object detection in unconstrained, cluttered scenes. The system derives much of its power from a representation that describes an object class in terms of an overcomplete dictionary of local, oriented, multiscale intensity differences between adjacent regions, efficiently computable as a Haar wavelet transform. This example-based learning approach implicitly derives a model of an object class by training a support vector machine classifier using a large set of positive and negative examples. We present results on face, people, and car detection tasks using the same architecture. In addition, we quantify how the representation affects detection performance by considering several alternate representations including pixels and principal components. We also describe a real-time application of our person detection system as part of a driver assistance system.